@phdthesis{Middelanis2023,
author = {Middelanis, Robin},
title = {Global response to local extremes—a storyline approach on economic loss propagation from weather extremes},
doi = {10.25932/publishup-61112},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-611127},
school = {Universit{\"a}t Potsdam},
pages = {vii, 237},
year = {2023},
abstract = {Due to anthropogenic greenhouse gas emissions, Earth's average surface temperature is steadily increasing. As a consequence, many weather extremes are likely to become more frequent and intense. This poses a threat to natural and human systems, with local impacts capable of destroying exposed assets and infrastructure, and disrupting economic and societal activity. Yet, these effects are not locally confined to the directly affected regions, as they can trigger indirect economic repercussions through loss propagation along supply chains. As a result, local extremes yield a potentially global economic response. To build economic resilience and design effective adaptation measures that mitigate adverse socio-economic impacts of ongoing climate change, it is crucial to gain a comprehensive understanding of indirect impacts and the underlying economic mechanisms. Presenting six articles in this thesis, I contribute towards this understanding. To this end, I expand on local impacts under current and future climate, the resulting global economic response, as well as the methods and tools to analyze this response. Starting with a traditional assessment of weather extremes under climate change, the first article investigates extreme snowfall in the Northern Hemisphere until the end of the century. Analyzing an ensemble of global climate model projections reveals an increase of the most extreme snowfall, while mean snowfall decreases. Assessing repercussions beyond local impacts, I employ numerical simulations to compute indirect economic effects from weather extremes with the numerical agent-based shock propagation model Acclimate. This model is used in conjunction with the recently emerged storyline framework, which involves analyzing the impacts of a particular reference extreme event and comparing them to impacts in plausible counterfactual scenarios under various climate or socio-economic conditions. Using this approach, I introduce three primary storylines that shed light on the complex mechanisms underlying economic loss propagation. In the second and third articles of this thesis, I analyze storylines for the historical Hurricanes Sandy (2012) and Harvey (2017) in the USA. For this, I first estimate local economic output losses and then simulate the resulting global economic response with Acclimate. The storyline for Hurricane Sandy thereby focuses on global consumption price anomalies and the resulting changes in consumption. I find that the local economic disruption leads to a global wave-like economic price ripple, with upstream effects propagating in the supplier direction and downstream effects in the buyer direction. Initially, an upstream demand reduction causes consumption price decreases, followed by a downstream supply shortage and increasing prices, before the anomalies decay in a normalization phase. A dominant upstream or downstream effect leads to net consumption gains or losses of a region, respectively. Moreover, I demonstrate that a longer direct economic shock intensifies the downstream effect for many regions, leading to an overall consumption loss. The third article of my thesis builds upon the developed loss estimation method by incorporating projections to future global warming levels. I use these projections to explore how the global production response to Hurricane Harvey would change under further increased global warming. The results show that, while the USA is able to nationally offset direct losses in the reference configuration, other countries have to compensate for increasing shares of counterfactual future losses. This compensation is mainly achieved by large exporting countries, but gradually shifts towards smaller regions. These findings not only highlight the economy's ability to flexibly mitigate disaster losses to a certain extent, but also reveal the vulnerability and economic disadvantage of regions that are exposed to extreme weather events. The storyline in the fourth article of my thesis investigates the interaction between global economic stress and the propagation of losses from weather extremes. I examine indirect impacts of weather extremes — tropical cyclones, heat stress, and river floods — worldwide under two different economic conditions: an unstressed economy and a globally stressed economy, as seen during the Covid-19 pandemic. I demonstrate that the adverse effects of weather extremes on global consumption are strongly amplified when the economy is under stress. Specifically, consumption losses in the USA and China double and triple, respectively, due to the global economy's decreased capacity for disaster loss compensation. An aggravated scarcity intensifies the price response, causing consumption losses to increase. Advancing on the methods and tools used here, the final two articles in my thesis extend the agent-based model Acclimate and formalize the storyline approach. With the model extension described in the fifth article, regional consumers make rational choices on the goods bought such that their utility is maximized under a constrained budget. In an out-of-equilibrium economy, these rational consumers are shown to temporarily increase consumption of certain goods in spite of rising prices. The sixth article of my thesis proposes a formalization of the storyline framework, drawing on multiple studies including storylines presented in this thesis. The proposed guideline defines eight central elements that can be used to construct a storyline. Overall, this thesis contributes towards a better understanding of economic repercussions of weather extremes. It achieves this by providing assessments of local direct impacts, highlighting mechanisms and impacts of loss propagation, and advancing on methods and tools used.},
language = {en}
}
@inproceedings{HeinischRomeikeKnobelsdorfetal.2013,
author = {Heinisch, Isabelle and Romeike, Ralf and Knobelsdorf, Maria and Kreitz, Christoph and Nyl{\´e}n, Aletta and D{\"o}rge, Christina and G{\"o}ttel, Timo and Holz, Jan and Bergner, Nadine and Schroeder, Ulrik and Metzger, Christiane and Haag, Johann and Abke, J{\"o}rg and Schwirtlich, Vincent and Sedelmaier, Yvonne and M{\"u}ller, Dorothee and Frommer, Andreas and Humbert, Ludger and Berges, Marc and M{\"u}hling, Andreas and Hubwieser, Peter and Steuer, Horst and Engbring, Dieter and Selke, Harald and Drews, Paul and Schirmer, Ingrid and Morisse, Marcel and Sagawe, Arno and Rolf, Arno and Friedemann, Stefan and Gr{\"o}ger, Stefan and Schumann, Matthias and Klinger, Melanie and Polutina, Olena and Bibel, Ariane and G{\"o}tz, Christian and Brinda, Torsten and Apel, Rebecca and Berg, Tobias and Bergner, Nadine and Chatti, Mohamed Amine and Leicht-Scholten, Carmen and Schroeder, Ulrik and Al-Saffar, Loay Talib and Petre, Marian and Schirmer, Ingrid and Rick, Detlef},
title = {HDI 2012 - Informatik f{\"u}r eine nachhaltige Zukunft : 5. Fachtagung Hochschuldidaktik der Informatik ; 06.-07. November 2012, Universit{\"a}t Hamburg},
editor = {Forbrig, Peter and Rick, Detlef and Schmolitzky, Axel},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-220-9},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-62891},
pages = {169},
year = {2013},
abstract = {Die Tagungsreihe zur Hochschuldidaktik der Informatik HDI wird vom Fachbereich Informatik und Ausbildung / Didaktik der Informatik (IAD) in der Gesellschaft f{\"u}r Informatik e. V. (GI) organisiert. Sie dient den Lehrenden der Informatik in Studieng{\"a}ngen an Hochschulen als Forum der Information und des Austauschs {\"u}ber neue didaktische Ans{\"a}tze und bildungspolitische Themen im Bereich der Hochschulausbildung aus der fachlichen Perspektive der Informatik. Diese f{\"u}nfte HDI 2012 wurde an der Universit{\"a}t Hamburg organisiert. F{\"u}r sie wurde das spezielle Motto „Informatik f{\"u}r eine nachhaltige Zukunft" gew{\"a}hlt, um insbesondere Fragen der Bildungsrelevanz informatischer Inhalte, der Kompetenzen f{\"u}r Studierende informatisch gepr{\"a}gter Studieng{\"a}nge und der Rolle der Informatik in der Hochschulentwicklung zu diskutieren.},
language = {de}
}
@inproceedings{FroitzheimBergnerSchroederetal.2015,
author = {Froitzheim, Manuel and Bergner, Nadine and Schroeder, Ulrik and Hurtienne, Dominik and Spannagel, Christian and Roderus, Simon and Wienkop, Uwe and Leonhardt, Thiemo and Kwiecien, Alexandra and Schmetz, Arno and Bellgardt, Martin and Naumann, Uwe and Weßels, Doris and Metzger, Christiane and L{\"a}ngrich, Matthias and Schulze, J{\"o}rg and Jakoblew, Marcel and Keil, Reinhard and Winkelnkemper, Felix and Engbring, Dieter and Klar, Tilman-Mathies and Kujath, Bertold and Sch{\"u}tze, Christopher and Fietkau, Julian and Kindsm{\"u}ller, Martin Christof and G{\"o}ttel, Timo and Bergner, Nadine and Taraschewski, Christian and Vosseberg, Karin and Czernik, Sofie and Erb, Ulrike and Vielhaber, Michael and Schlierkamp, Kathrin and Thurner, Veronika and Br{\"o}ker, Kathrin},
title = {HDI 2014 - Gestalten von {\"U}berg{\"a}ngen},
editor = {Forbrig, Peter and Magenheim, Johannes},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-313-8},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-74920},
pages = {186},
year = {2015},
abstract = {Die Tagung HDI 2014 in Freiburg zur Hochschuldidaktik der Informatik HDI wurde erneut vom Fachbereich Informatik und Ausbildung / Didaktik der Informatik (IAD) in der Gesellschaft f{\"u}r Informatik e. V. (GI) organisiert. Sie dient den Lehrenden der Informatik in Studieng{\"a}ngen an Hochschulen als Forum der Information und des Austauschs {\"u}ber neue didaktische Ans{\"a}tze und bildungspolitische Themen im Bereich der Hochschulausbildung aus der fachlichen Perspektive der Informatik. Die HDI 2014 ist nun bereits die sechste Ausgabe der HDI. F{\"u}r sie wurde das spezielle Motto „Gestalten und Meistern von {\"U}berg{\"a}ngen" gew{\"a}hlt. Damit soll ein besonderes Augenmerk auf die {\"U}berg{\"a}nge von Schule zum Studium, vom Bachelor zum Master, vom Studium zur Promotion oder vom Studium zur Arbeitswelt gelegt werden.},
language = {de}
}
@inproceedings{RolfBergesHubwieseretal.2010,
author = {Rolf, Arno and Berges, Marc and Hubwieser, Peter and Kehrer, Timo and Kelter, Udo and Romeike, Ralf and Frenkel, Marcus and Karsten, Weicker and Reinhardt, Wolfgang and Mascher, Michael and G{\"u}l, Senol and Magenheim, Johannes and Raimer, Stephan and Diethelm, Ira and D{\"u}nnebier, Malte and Gabor, Kiss and Susanne, Boll and Rolf, Meinhardt and Gronewold, Sabine and Krekeler, Larissa and Jahnke, Isa and Haertel, Tobias and Mattick, Volker and Lettow, Karsten and Hafer, J{\"o}rg and Ludwig, Joachim and Schumann, Marlen and Laroque, Christoph and Schulte, Jonas and Urban, Diana},
title = {HDI2010 - Tagungsband der 4. Fachtagung zur "Hochschuldidaktik Informatik"},
editor = {Engbring, Dieter and Keil, Reinhard and Magenheim, Johannes and Selke, Harald},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-100-4},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-49167},
pages = {105},
year = {2010},
abstract = {Mit der 4. Tagung zur Hochschuldidaktik Informatik wird eine Reihe fortgesetzt, die ihren Anfang 1998 in Stuttgart unter der {\"U}berschrift „Informatik und Ausbildung" genommen hat. Seither dienen diese Tagungen den Lehrenden im Bereich der Hochschulinformatik als Forum der Information und des Diskurses {\"u}ber aktuelle didaktische und bildungspolitische Entwicklungen im Bereich der Informatikausbildung. Aktuell z{\"a}hlen dazu insbesondere Fragen der Bildungsrelevanz informatischer Inhalte und der Herausforderung durch eine st{\"a}rkere Kompetenzorientierung in der Informatik. Die eingereichten Beitr{\"a}ge zur HDI 2010 in Paderborn veranschaulichen unterschiedliche Bem{\"u}hungen, sich mit relevanten Problemen der Informatikdidaktik an Hochschulen in Deutschland (und z. T. auch im Ausland) auseinanderzusetzen. Aus der Breite des Spektrums der Einreichungen ergaben sich zugleich Probleme bei der Begutachtung. Letztlich konnten von den zahlreichen Einreichungen nur drei die Gutachter so {\"u}berzeugen, dass sie uneingeschr{\"a}nkt in ihrer Langfassung akzeptiert wurden. Neun weitere Einreichungen waren trotz Kritik {\"u}berwiegend positiv begutachtet worden, so dass wir diese als Kurzfassung bzw. Diskussionspapier in die Tagung aufgenommen haben.},
language = {de}
}
@inproceedings{DennertMoellerGarmannKujathetal.2016,
author = {Dennert-M{\"o}ller, Elisabeth and Garmann, Robert and Kujath, Bertold and Zscheyge, Oliver and Weicker, Karsten and B{\"o}hne, Sebastian and Knobelsdorf, Maria and Kreitz, Christoph and Steen, Alexander and Wisniewski, Max and Benzm{\"u}ller, Christoph and Gebhardt, Kai and Ehlenz, Matthias and Bergner, Nadine and Schroeder, Ulrik},
title = {Hochschuldidaktik der Informatik},
editor = {Schwill, Andreas and Lucke, Ulrike},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-376-3},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-93511},
pages = {102},
year = {2016},
abstract = {Die 7. Fachtagung f{\"u}r Hochschuldidaktik, die 2016 erneut mit der DeLFI E-Learning Fachtagung Informatik stattfand, setzte das erfolgreiche Modell einer Tagung fort, die sich mit hochschuldidaktischen Fragen und der Gestaltung von Studieng{\"a}ngen der Informatik besch{\"a}ftigt. Thema der Tagung waren alle Fragen, die sich der Vermittlung von Informatikgegenst{\"a}nden im Hochschulbereich widmen. Dazu geh{\"o}rten u.a.: • fachdidaktische Konzepte der Vermittlung einzelner Informatikgegenst{\"a}nde • methodische L{\"o}sungen, wie spezielle Lehr- und Lernformen, Durchf{\"u}hrungskonzepte • empirische Ergebnisse und Vergleichsstudien • E-Learning-Ans{\"a}tze, wenn sie ein erkennbares didaktisches Konzept verfolgen • Studienkonzepte und Curricula, organisatorische Fragen, wie Gewinnung von Studierenden, Studieneingangsphase, Abbrecher. Die Fachtagung widmete sich ausgew{\"a}hlten Fragestellungen dieses Themenkomplexes, die durch Vortr{\"a}ge ausgewiesener Experten, durch eingereichte Beitr{\"a}ge und durch Pr{\"a}sentationen und Poster intensiv behandelt wurden. Unser besonderer Dank gilt dem Programmkomitee und den hier nicht genannten Helfern f{\"u}r ihren Einsatz bei der Vorbereitung und Durchf{\"u}hrung der Tagung.},
language = {de}
}
@inproceedings{KeilKoubekMartensetal.2009,
author = {Keil, Reinhard and Koubek, Jochen and Martens, Alke and Schulte, Carsten and Bieniusa, Annette and Degen, Markus and Heidegger, Phillip and Thiemann, Peter and Gasbichler, Martin and Crestani, Marcus and Klaeren, Herbert and Knauel, Eric and Sperber, Michael and Eirund, Helmut and Sethmann, Richard and Weicker, Nicole and Weicker, Karsten and Reinhardt, Wolfgang and Magenheim, Johannes and Bender, Katrin and Steinert, Markus and Schwidrowski, Kirstin and Schmidt, Thilo and Br{\"u}ck, Rainer and Freischlad, Stefan and Schubert, Sigrid and Stechert, Peer and Kujath, Bertold},
title = {Hochschuldidaktik der Informatik : HDI2008 - 3. Workshop des GI-Fachbereichs Ausbildung und Beruf/Didaktik der Informatik ; 04. - 05. Dezember 2008 an der Universit{\"a}t Potsdam},
editor = {Schwill, Andreas},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-940793-75-1},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-28080},
pages = {151},
year = {2009},
abstract = {Thema des Workshops waren alle Fragen, die sich der Vermittlung von Informatikgegenst{\"a}nden im Hochschulbereich widmen. Dazu geh{\"o}ren u.a.: - fachdidaktische Konzepte der Vermittlung einzelner Informatikgegenst{\"a}nde - methodische L{\"o}sungen, wie spezielle Lehr- und Lernformen, Durchf{\"u}hrungskonzepte - Studienkonzepte und Curricula, insbesondere im Zusammenhang mit Bachelor- und Masterstudieng{\"a}ngen - E-Learning-Ans{\"a}tze, wenn sie ein erkennbares didaktisches Konzept verfolgen empirische Ergebnisse und Vergleichsstudien. Die Fachtagung widmete sich ausgew{\"a}hlten Fragestellungen dieses Themenkomplexes, die durch Vortr{\"a}ge ausgewiesener Experten, durch eingereichte Beitr{\"a}ge und durch eine Pr{\"a}sentation intensiv behandelt wurden.},
language = {de}
}
@inproceedings{SeegererRomeikeTillmannetal.2018,
author = {Seegerer, Stefan and Romeike, Ralf and Tillmann, Alexander and Kr{\"o}mker, Detlef and Horn, Florian and Gattinger, Thorsten and Weicker, Karsten and Schmitz, Dennis and Moldt, Daniel and R{\"o}pke, Ren{\´e} and Larisch, Kathrin and Schroeder, Ulrik and Keverp{\"u}tz, Claudia and K{\"u}ppers, Bastian and Striewe, Michael and Kramer, Matthias and Grillenberger, Andreas and Frede, Christiane and Knobelsdorf, Maria and Greven, Christoph},
title = {Hochschuldidaktik der Informatik HDI 2018},
series = {Commentarii informaticae didacticae (CID)},
booktitle = {Commentarii informaticae didacticae (CID)},
number = {12},
editor = {Bergner, Nadine and R{\"o}pke, Ren{\´e} and Schroeder, Ulrik and Kr{\"o}mker, Detlef},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-435-7},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-413542},
pages = {161},
year = {2018},
abstract = {Die 8. Fachtagung f{\"u}r Hochschuldidaktik der Informatik (HDI) fand im September 2018 zusammen mit der Deutschen E-Learning Fachtagung Informatik (DeLFI) unter dem gemeinsamen Motto „Digitalisierungswahnsinn? - Wege der Bildungstransformationen" in Frankfurt statt. Dabei widmet sich die HDI allen Fragen der informatischen Bildung im Hochschulbereich. Schwerpunkte bildeten in diesem Jahr u. a.: - Analyse der Inhalte und anzustrebenden Kompetenzen in Informatikveranstaltungen - Programmieren lernen \& Einstieg in Softwareentwicklung - Spezialthemen: Data Science, Theoretische Informatik und Wissenschaftliches Arbeiten Die Fachtagung widmet sich ausgew{\"a}hlten Fragestellungen dieser Themenkomplexe, die durch Vortr{\"a}ge ausgewiesener Experten und durch eingereichte Beitr{\"a}ge intensiv behandelt werden.},
language = {de}
}
@inproceedings{DeselOpelSiegerisetal.2023,
author = {Desel, J{\"o}rg and Opel, Simone and Siegeris, Juliane and Draude, Claude and Weber, Gerhard and Schell, Timon and Schwill, Andreas and Thorbr{\"u}gge, Carsten and Sch{\"a}fer, Len Ole and Netzer, Cajus Marian and Gerstenberger, Dietrich and Winkelnkemper, Felix and Schulte, Carsten and B{\"o}ttcher, Axel and Thurner, Veronika and H{\"a}fner, Tanja and Ottinger, Sarah and Große-B{\"o}lting, Gregor and Scheppach, Lukas and M{\"u}hling, Andreas and Baberowski, David and Leonhardt, Thiemo and Rentsch, Susanne and Bergner, Nadine and Bonorden, Leif and Stemme, Jonas and Hoppe, Uwe and Weicker, Karsten and Bender, Esther and Barbas, Helena and Hamann, Fabian and Soll, Marcus and Sitzmann, Daniel},
title = {Hochschuldidaktik Informatik HDI 2021},
series = {Commentarii informaticae didacticae},
booktitle = {Commentarii informaticae didacticae},
number = {13},
editor = {Desel, J{\"o}rg and Opel, Simone and Siegeris, Juliane},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-548-4},
issn = {1868-0844},
doi = {10.25932/publishup-56507},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-565070},
pages = {299},
year = {2023},
abstract = {Die Fachtagungen HDI (Hochschuldidaktik Informatik) besch{\"a}ftigen sich mit den unterschiedlichen Aspekten informatischer Bildung im Hochschulbereich. Neben den allgemeinen Themen wie verschiedenen Lehr- und Lernformen, dem Einsatz von Informatiksystemen in der Hochschullehre oder Fragen der Gewinnung von geeigneten Studierenden, deren Kompetenzerwerb oder auch der Betreuung der Studierenden widmet sich die HDI immer auch einem Schwerpunktthema. Im Jahr 2021 war dies die Ber{\"u}cksichtigung von Diversit{\"a}t in der Lehre. Diskutiert wurden beispielsweise die Einbeziehung von besonderen fachlichen und {\"u}berfachlichen Kompetenzen Studierender, der Unterst{\"u}tzung von Durchl{\"a}ssigkeit aus nichtakademischen Berufen, aber auch die Gestaltung inklusiver Lehr- und Lernszenarios, Aspekte des Lebenslangen Lernens oder sich an die Diversit{\"a}t von Studierenden adaptierte oder adaptierende Lehrsysteme. Dieser Band enth{\"a}lt ausgew{\"a}hlte Beitr{\"a}ge der 9. Fachtagung 2021, die in besonderer Weise die Konferenz und die dort diskutierten Themen repr{\"a}sentieren.},
language = {de}
}
@article{MainaAngondiWaga2015,
author = {Maina, Anthony Gioko and Angondi, Enos Kiforo and Waga, Rosemary},
title = {How does the Implementation of a Literacy Learning Tool Kit influence Literacy Skill Acquisition?},
series = {KEYCIT 2014 - Key Competencies in Informatics and ICT},
journal = {KEYCIT 2014 - Key Competencies in Informatics and ICT},
number = {7},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-82856},
pages = {319 -- 326},
year = {2015},
abstract = {This study aimed at following how teachers transfer skills into results while using ABRA literacy software. This was done in the second part of the pilot study whose aim was to provide equity to control group teachers and students by exposing them to the ABRACADABRA treatment after the end of phase 1. This opportunity was used to follow the phase 1 teachers to see how the skills learned were being transformed into results. A standard three-day initial training and planning session on how to use ABRA to teach literacy was held at the beginning of each phase for ABRA teachers (phase 1 experimental and phase 2 delayed ABRA). Teachers were provided with teaching materials including a tentative ABRA curriculum developed to align with the Kenyan English Language requirements for year 1 and 3 students. Results showed that although there was no significant difference between the groups in vocabulary-related subscales which include word reading and meaning as well as sentence comprehension, students in ABRACADABRA classes improved their scores at a significantly higher rate than students in control classes in comprehension related scores. An average student in the ABRACADABRA group improved by 12 and 16 percentile points respectively compared to their counterparts in the control group.},
language = {en}
}
@article{Weigend2015,
author = {Weigend, Michael},
title = {How Things Work},
series = {KEYCIT 2014 - Key Competencies in Informatics and ICT},
journal = {KEYCIT 2014 - Key Competencies in Informatics and ICT},
number = {7},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-82814},
pages = {285 -- 298},
year = {2015},
abstract = {Recognizing and defining functionality is a key competence adopted in all kinds of programming projects. This study investigates how far students without specific informatics training are able to identify and verbalize functions and parameters. It presents observations from classroom activities on functional modeling in high school chemistry lessons with altogether 154 students. Finally it discusses the potential of functional modelling to improve the comprehension of scientific content.},
language = {en}
}
@phdthesis{Schumacher2017,
author = {Schumacher, Kinga},
title = {Hybride semantische Suche - eine Kombination aus Fakten- und Dokumentretrieval},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-405973},
school = {Universit{\"a}t Potsdam},
pages = {vii, 187},
year = {2017},
abstract = {Das Thema der vorliegenden Arbeit ist die semantische Suche im Kontext heutiger Informationsmanagementsysteme. Zu diesen Systemen z{\"a}hlen Intranets, Web 3.0-Anwendungen sowie viele Webportale, die Informationen in heterogenen Formaten und Strukturen beinhalten. Auf diesen befinden sich einerseits Daten in strukturierter Form und andererseits Dokumente, die inhaltlich mit diesen Daten in Beziehung stehen. Diese Dokumente sind jedoch in der Regel nur teilweise strukturiert oder vollst{\"a}ndig unstrukturiert. So beschreiben beispielsweise Reiseportale durch strukturierte Daten den Zeitraum, das Reiseziel, den Preis einer Reise und geben in unstrukturierter Form weitere Informationen, wie Beschreibungen zum Hotel, Zielort, Ausflugsziele an. Der Fokus heutiger semantischer Suchmaschinen liegt auf dem Finden von Wissen entweder in strukturierter Form, auch Faktensuche genannt, oder in semi- bzw. unstrukturierter Form, was {\"u}blicherweise als semantische Dokumentensuche bezeichnet wird. Einige wenige Suchmaschinen versuchen die L{\"u}cke zwischen diesen beiden Ans{\"a}tzen zu schließen. Diese durchsuchen zwar gleichzeitig strukturierte sowie unstrukturierte Daten, werten diese jedoch entweder weitgehend voneinander unabh{\"a}ngig aus oder schr{\"a}nken die Suchm{\"o}glichkeiten stark ein, indem sie beispielsweise nur bestimmte Fragemuster unterst{\"u}tzen. Hierdurch werden die im System verf{\"u}gbaren Informationen nicht ausgesch{\"o}pft und gleichzeitig unterbunden, dass Zusammenh{\"a}nge zwischen einzelnen Inhalten der jeweiligen Informationssysteme und sich erg{\"a}nzende Informationen den Benutzer erreichen.
Um diese L{\"u}cke zu schließen, wurde in der vorliegenden Arbeit ein neuer hybrider semantischer Suchansatz entwickelt und untersucht, der strukturierte und semi- bzw. unstrukturierte Inhalte w{\"a}hrend des gesamten Suchprozesses kombiniert. Durch diesen Ansatz werden nicht nur sowohl Fakten als auch Dokumente gefunden, es werden auch Zusammenh{\"a}nge, die zwischen den unterschiedlich strukturierten Daten bestehen, in jeder Phase der Suche genutzt und fließen in die Suchergebnisse mit ein. Liegt die Antwort zu einer Suchanfrage nicht vollst{\"a}ndig strukturiert, in Form von Fakten, oder unstrukturiert, in Form von Dokumenten vor, so liefert dieser Ansatz eine Kombination der beiden. Die Ber{\"u}cksichtigung von unterschiedlich Inhalten w{\"a}hrend des gesamten Suchprozesses stellt jedoch besondere Herausforderungen an die Suchmaschine. Diese muss in der Lage sein, Fakten und Dokumente in Abh{\"a}ngigkeit voneinander zu durchsuchen, sie zu kombinieren sowie die unterschiedlich strukturierten Ergebnisse in eine geeignete Rangordnung zu bringen. Weiterhin darf die Komplexit{\"a}t der Daten nicht an die Endnutzer weitergereicht werden. Die Darstellung der Inhalte muss vielmehr sowohl bei der Anfragestellung als auch bei der Darbietung der Ergebnisse verst{\"a}ndlich und leicht interpretierbar sein. Die zentrale Fragestellung der Arbeit ist, ob ein hybrider Ansatz auf einer vorgegebenen Datenbasis die Suchanfragen besser beantworten kann als die semantische Dokumentensuche und die Faktensuche f{\"u}r sich genommen, bzw. als eine Suche die diese Ans{\"a}tze im Rahmen des Suchprozesses nicht kombiniert. Die durchgef{\"u}hrten Evaluierungen aus System- und aus Benutzersicht zeigen, dass die im Rahmen der Arbeit entwickelte hybride semantische Suchl{\"o}sung durch die Kombination von strukturierten und unstrukturierten Inhalten im Suchprozess bessere Antworten liefert als die oben genannten Verfahren und somit Vorteile gegen{\"u}ber bisherigen Ans{\"a}tzen bietet. Eine Befragung von Benutzern macht deutlich, dass die hybride semantische Suche als verst{\"a}ndlich empfunden und f{\"u}r heterogen strukturierte Datenmengen bevorzugt wird.},
language = {de}
}
@article{Jones2015,
author = {Jones, Anthony},
title = {ICT Competencies for School Students},
series = {KEYCIT 2014 - Key Competencies in Informatics and ICT},
journal = {KEYCIT 2014 - Key Competencies in Informatics and ICT},
number = {7},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-82663},
pages = {171 -- 179},
year = {2015},
abstract = {This paper discusses results from a small-scale research study, together with some recently published research into student perceptions of ICT for learning in schools, to consider relevant skills that do not appear to currently being taught. The paper concludes by raising three issues relating to learning with and through ICT that need to be addressed in school curricula and classroom teaching.},
language = {en}
}
@article{PassigTzurielKedmi2015,
author = {Passig, David and Tzuriel, David and Kedmi, Ganit Eshel},
title = {Improving children's Cognitive Modifiability through Mediated Learning and Dynamic Assessment within 3D Immersive Virtual Reality Environment},
series = {KEYCIT 2014 - Key Competencies in Informatics and ICT},
journal = {KEYCIT 2014 - Key Competencies in Informatics and ICT},
number = {7},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-82705},
pages = {235 -- 252},
year = {2015},
abstract = {The objectives of this study were to examine (a) the effect of dynamic assessment (DA) in a 3D Immersive Virtual Reality (IVR) environment as compared with computerized 2D and noncomputerized (NC) situations on cognitive modifiability, and (b) the transfer effects of these conditions on more difficult problem solving administered two weeks later in a non-computerized environment. A sample of 117 children aged 6:6-9:0 years were randomly assigned into three experimental groups of DA conditions: 3D, 2D, and NC, and one control group (C). All groups received the pre- and post-teaching Analogies subtest of the Cognitive Modifiability Battery (CMB-AN). The experimental groups received a teaching phase in conditions similar to the pre-and post-teaching phases. The findings showed that cognitive modifiability, in a 3D IVR, was distinctively higher than in the two other experimental groups (2D computer group and NC group). It was also found that the 3D group showed significantly higher performance in transfer problems than the 2D and NC groups.},
language = {en}
}
@phdthesis{Boeken2022,
author = {B{\"o}ken, Bj{\"o}rn},
title = {Improving prediction accuracy using dynamic information},
doi = {10.25932/publishup-58512},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-585125},
school = {Universit{\"a}t Potsdam},
pages = {xii, 160},
year = {2022},
abstract = {Accurately solving classification problems nowadays is likely to be the most relevant machine learning task. Binary classification separating two classes only is algorithmically simpler but has fewer potential applications as many real-world problems are multi-class. On the reverse, separating only a subset of classes simplifies the classification task. Even though existing multi-class machine learning algorithms are very flexible regarding the number of classes, they assume that the target set Y is fixed and cannot be restricted once the training is finished. On the other hand, existing state-of-the-art production environments are becoming increasingly interconnected with the advance of Industry 4.0 and related technologies such that additional information can simplify the respective classification problems. In light of this, the main aim of this thesis is to introduce dynamic classification that generalizes multi-class classification such that the target class set can be restricted arbitrarily to a non-empty class subset M of Y at any time between two consecutive predictions. This task is solved by a combination of two algorithmic approaches. First, classifier calibration, which transforms predictions into posterior probability estimates that are intended to be well calibrated. The analysis provided focuses on monotonic calibration and in particular corrects wrong statements that appeared in the literature. It also reveals that bin-based evaluation metrics, which became popular in recent years, are unjustified and should not be used at all. Next, the validity of Platt scaling, which is the most relevant parametric calibration approach, is analyzed in depth. In particular, its optimality for classifier predictions distributed according to four different families of probability distributions as well its equivalence with Beta calibration up to a sigmoidal preprocessing are proven. For non-monotonic calibration, extended variants on kernel density estimation and the ensemble method EKDE are introduced. Finally, the calibration techniques are evaluated using a simulation study with complete information as well as on a selection of 46 real-world data sets. Building on this, classifier calibration is applied as part of decomposition-based classification that aims to reduce multi-class problems to simpler (usually binary) prediction tasks. For the involved fusing step performed at prediction time, a new approach based on evidence theory is presented that uses classifier calibration to model mass functions. This allows the analysis of decomposition-based classification against a strictly formal background and to prove closed-form equations for the overall combinations. Furthermore, the same formalism leads to a consistent integration of dynamic class information, yielding a theoretically justified and computationally tractable dynamic classification model. The insights gained from this modeling are combined with pairwise coupling, which is one of the most relevant reduction-based classification approaches, such that all individual predictions are combined with a weight. This not only generalizes existing works on pairwise coupling but also enables the integration of dynamic class information. Lastly, a thorough empirical study is performed that compares all newly introduced approaches to existing state-of-the-art techniques. For this, evaluation metrics for dynamic classification are introduced that depend on corresponding sampling strategies. Thereafter, these are applied during a three-part evaluation. First, support vector machines and random forests are applied on 26 data sets from the UCI Machine Learning Repository. Second, two state-of-the-art deep neural networks are evaluated on five benchmark data sets from a relatively recent reference work. Here, computationally feasible strategies to apply the presented algorithms in combination with large-scale models are particularly relevant because a naive application is computationally intractable. Finally, reference data from a real-world process allowing the inclusion of dynamic class information are collected and evaluated. The results show that in combination with support vector machines and random forests, pairwise coupling approaches yield the best results, while in combination with deep neural networks, differences between the different approaches are mostly small to negligible. Most importantly, all results empirically confirm that dynamic classification succeeds in improving the respective prediction accuracies. Therefore, it is crucial to pass dynamic class information in respective applications, which requires an appropriate digital infrastructure.},
language = {en}
}
@phdthesis{Dornhege2006,
author = {Dornhege, Guido},
title = {Increasing information transfer rates for brain-computer interfacing},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-7690},
school = {Universit{\"a}t Potsdam},
year = {2006},
abstract = {The goal of a Brain-Computer Interface (BCI) consists of the development of a unidirectional interface between a human and a computer to allow control of a device only via brain signals. While the BCI systems of almost all other groups require the user to be trained over several weeks or even months, the group of Prof. Dr. Klaus-Robert M{\"u}ller in Berlin and Potsdam, which I belong to, was one of the first research groups in this field which used machine learning techniques on a large scale. The adaptivity of the processing system to the individual brain patterns of the subject confers huge advantages for the user. Thus BCI research is considered a hot topic in machine learning and computer science. It requires interdisciplinary cooperation between disparate fields such as neuroscience, since only by combining machine learning and signal processing techniques based on neurophysiological knowledge will the largest progress be made. In this work I particularly deal with my part of this project, which lies mainly in the area of computer science. I have considered the following three main points: Establishing a performance measure based on information theory: I have critically illuminated the assumptions of Shannon's information transfer rate for application in a BCI context. By establishing suitable coding strategies I was able to show that this theoretical measure approximates quite well to what is practically achieveable. Transfer and development of suitable signal processing and machine learning techniques: One substantial component of my work was to develop several machine learning and signal processing algorithms to improve the efficiency of a BCI. Based on the neurophysiological knowledge that several independent EEG features can be observed for some mental states, I have developed a method for combining different and maybe independent features which improved performance. In some cases the performance of the combination algorithm outperforms the best single performance by more than 50 \%. Furthermore, I have theoretically and practically addressed via the development of suitable algorithms the question of the optimal number of classes which should be used for a BCI. It transpired that with BCI performances reported so far, three or four different mental states are optimal. For another extension I have combined ideas from signal processing with those of machine learning since a high gain can be achieved if the temporal filtering, i.e., the choice of frequency bands, is automatically adapted to each subject individually. Implementation of the Berlin brain computer interface and realization of suitable experiments: Finally a further substantial component of my work was to realize an online BCI system which includes the developed methods, but is also flexible enough to allow the simple realization of new algorithms and ideas. So far, bitrates of up to 40 bits per minute have been achieved with this system by absolutely untrained users which, compared to results of other groups, is highly successful.},
subject = {Kybernetik},
language = {en}
}
@phdthesis{Harmeling2004,
author = {Harmeling, Stefan},
title = {Independent component analysis and beyond},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-0001540},
school = {Universit{\"a}t Potsdam},
year = {2004},
abstract = {'Independent component analysis' (ICA) ist ein Werkzeug der statistischen Datenanalyse und Signalverarbeitung, welches multivariate Signale in ihre Quellkomponenten zerlegen kann. Obwohl das klassische ICA Modell sehr n{\"u}tzlich ist, gibt es viele Anwendungen, die Erweiterungen von ICA erfordern. In dieser Dissertation pr{\"a}sentieren wir neue Verfahren, die die Funktionalit{\"a}t von ICA erweitern: (1) Zuverl{\"a}ssigkeitsanalyse und Gruppierung von unabh{\"a}ngigen Komponenten durch Hinzuf{\"u}gen von Rauschen, (2) robuste und {\"u}berbestimmte ('over-complete') ICA durch Ausreissererkennung, und (3) nichtlineare ICA mit Kernmethoden.},
language = {en}
}
@article{DagieneStupuriene2015,
author = {Dagiene, Valentina and Stupuriene, Gabriele},
title = {Informatics Education based on Solving Attractive Tasks through a Contest},
series = {KEYCIT 2014 - Key Competencies in Informatics and ICT},
journal = {KEYCIT 2014 - Key Competencies in Informatics and ICT},
number = {7},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-82626},
pages = {97 -- 115},
year = {2015},
abstract = {The paper discusses the issue of supporting informatics (computer science) education through competitions for lower and upper secondary school students (8-19 years old). Competitions play an important role for learners as a source of inspiration, innovation, and attraction. Running contests in informatics for school students for many years, we have noticed that the students consider the contest experience very engaging and exciting as well as a learning experience. A contest is an excellent instrument to involve students in problem solving activities. An overview of infrastructure and development of an informatics contest from international level to the national one (the Bebras contest on informatics and computer fluency, originated in Lithuania) is presented. The performance of Bebras contests in 23 countries during the last 10 years showed an unexpected and unusually high acceptance by school students and teachers. Many thousands of students participated and got a valuable input in addition to their regular informatics lectures at school. In the paper, the main attention is paid to the developed tasks and analysis of students' task solving results in Lithuania.},
language = {en}
}
@article{BollMeinhardtGronewoldetal.2010,
author = {Boll, Susanne and Meinhardt, Rolf and Gronewold, Sabine and Krekeler, Larissa},
title = {Informatik f{\"u}r Migratinnen und Migranten Einf{\"u}hrung eines neuen Studienprogramms an der Universit{\"a}t Oldenburg},
series = {Commentarii informaticae didacticae : (CID)},
journal = {Commentarii informaticae didacticae : (CID)},
number = {4},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-64370},
pages = {79 -- 86},
year = {2010},
abstract = {F{\"u}r die Integration und den Bedarf der hochqualifizierten Migranten auf dem Arbeitsmarkt in Deutschland gibt es viele {\"U}berlegungen, aber noch keine ausreichenden L{\"o}sungen. Dieser Artikel beschreibt eine praktische L{\"o}sung {\"u}ber die Umsetzung des Konzepts f{\"u}r die Qualifizierung der akademischen Migranten am Beispiel eines Studienprogramms in Informatik an der Universit{\"a}t Oldenburg.},
language = {de}
}
@article{BergesMuehlingHubwieseretal.2013,
author = {Berges, Marc and M{\"u}hling, Andreas and Hubwieser, Peter and Steuer, Horst},
title = {Informatik f{\"u}r Nichtinformatiker},
series = {Commentarii informaticae didacticae : (CID)},
journal = {Commentarii informaticae didacticae : (CID)},
number = {5},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-64962},
pages = {105 -- 110},
year = {2013},
abstract = {Wir stellen die Konzeption und erste Ergebnisse einer neuartigen Informatik- Lehrveranstaltung f{\"u}r Studierende der Geod{\"a}sie vor. Das Konzept verbindet drei didaktische Ideen: Kontextorientierung, Peer-Tutoring und Praxisbezug (Course). Die Studierenden sollen dabei in zwei Semestern wichtige Grundlagen der Informatik verstehen und anzuwenden lernen. Durch enge Verzahnung der Aufgaben mit einem f{\"u}r Nichtinformatiker relevanten Kontext, sowie einem sehr hohen Anteil von Selbstt{\"a}tigkeit der Studierenden soll die Motivation f{\"u}r fachfremde Themen gesteigert werden. Die Ergebnisse zeigen, dass die Veranstaltung sehr erfolgreich war.},
language = {de}
}
@article{MuellerFrommerHumbert2013,
author = {M{\"u}ller, Dorothee and Frommer, Andreas and Humbert, Ludger},
title = {Informatik im Alltag},
series = {Commentarii informaticae didacticae : (CID)},
journal = {Commentarii informaticae didacticae : (CID)},
number = {5},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-64959},
pages = {98 -- 104},
year = {2013},
abstract = {Die Fachwissenschaft Informatik stellt Mittel bereit, deren Nutzung f{\"u}r Studierende heutzutage selbstverst{\"a}ndlich ist. Diese Tatsache darf uns allerdings nicht dar- {\"u}ber hinwegt{\"a}uschen, dass Studierende in der Regel keine Grundlage im Sinne einer informatischen Allgemeinbildung gem{\"a}{\"y} der Bildungsstandards der Gesellschaft f{\"u}r Informatik besitzen. Das Schulfach Informatik hat immer noch keinen durchg{\"a}ngigen Platz in den Stundentafeln der allgemein bildenden Schule gefunden. Zuk{\"u}nftigen Lehrkr{\"a}ften ist im Rahmen der bildungswissenschaftlichen Anteile im Studium eine hinreichende Medienkompetenz zu vermitteln. Mit der {\"u}berragenden Bedeutung der digitalen Medien kann dies nur auf der Grundlage einer ausreichenden informatischen Grundbildung erfolgen. Damit ist es angezeigt, ein Studienangebot bereitzustellen, das allen Studierenden ein Eintauchen in Elemente (Fachgebiete) der Fachwissenschaft Informatik aus der Sicht des Alltags bietet. An diesen Elementen werden exemplarisch verschiedene Aspekte der Fachwissenschaft beleuchtet, um einen Einblick in die Vielgestaltigkeit der Fragen und L{\"o}sungsstrategien der Informatik zu erlauben und so die informatische Grundbildung zu bef{\"o}rdern.},
language = {de}
}
@article{EngbringSelke2013,
author = {Engbring, Dieter and Selke, Harald},
title = {Informatik und Gesellschaft als Gebiet der Informatik},
series = {Commentarii informaticae didacticae : (CID)},
journal = {Commentarii informaticae didacticae : (CID)},
number = {5},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-64977},
pages = {111 -- 116},
year = {2013},
abstract = {In diesem Beitrag berichten wir {\"u}ber die Erfahrungen einer umgestalteten Lehre im Bereich Informatik und Gesellschft (IuG). Die Gr{\"u}nde f{\"u}r die Umge staltung und die Konzeption werden skizziert. Die Erfahrungen haben wir zu Thesen verdichtet: 1. Informatik und Gesellschaft sollte eine Pflichtveranstaltung im Bachelor-Studium sein, in der Studierende einen {\"U}berblick erhalten, welche gesellschaftlichen Rahmenbedingungen f{\"u}r sie relevant sind und wie man diese in die Praxis mit einbeziehen kann. 2. Historische Inhalte der Informatik sollen hier aufgearbeitet werden, indem man aktuelle Entwicklungen im Kontext ihrer Genese betrachtet.},
language = {de}
}
@article{Kujath2009,
author = {Kujath, Bertold},
title = {Informatischen Hochleistern {\"u}ber die Schulter geschaut : was k{\"o}nnen schwache Probleml{\"o}ser lernen},
series = {Commentarii informaticae didacticae : (CID)},
journal = {Commentarii informaticae didacticae : (CID)},
number = {1},
issn = {2191-0898},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-29123},
pages = {145 -- 149},
year = {2009},
abstract = {Leistungsstarke Probleml{\"o}ser zeigen ein deutlich anderes Vorgehen beim Bearbeiten von typischen Informatikproblemen als schw{\"a}chere Probleml{\"o}ser, das hat eine Studie mit Hochleistern und einer Vergleichsgruppe mit Informatikstudierenden ergeben. Auff{\"a}llig war das Fehlen informatikspezifischer Herangehensweisen bei der Problembearbeitung durch die Vergleichsgruppe, obwohl ihnen die dazu notwendigen Werkzeuge wie etwa Baumstrukturen oder Rekursion durchaus bekannt waren. Die Frage, wie nun die deutlich effizienteren Strategien der Hochleister didaktisch aufgearbeitet werden k{\"o}nnen, um sie an schwache Probleml{\"o}ser zu vermitteln, wird im vorliegen Beitrag anhand der Konzeption eines Lehrvideos diskutiert.},
language = {de}
}
@article{ReinhardtMascherGueletal.2010,
author = {Reinhardt, Wolfgang and Mascher, Michael and G{\"u}l, Senol and Magenheim, Johannes},
title = {Integration eines Rapid-Feedback-Moduls in eine koaktive Lern- und Arbeitsumgebung},
series = {Commentarii informaticae didacticae : (CID)},
journal = {Commentarii informaticae didacticae : (CID)},
number = {4},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-64339},
pages = {53 -- 58},
year = {2010},
abstract = {Die Evaluierung von Lehrveranstaltungen hat in vielen Lehreinrichtungen eine lange Tradition. In diesen klassischen Evaluierungsszenarien werden einmalig pro Semester Umfrageb{\"o}gen an die Studierenden verteilt und anschließend manuell ausgewertet. Die Ergebnisse sind dann zumeist am Ende der Vorlesungszeit vorhanden und geben einen punktuellen Einblick in die Qualit{\"a}t der Lehrveranstaltung bis zum Zeitpunkt der durchgef{\"u}hrten Evaluation. In diesem Artikel stellen wir das Konzept des Rapid Feedback, seine Einsatzm{\"o}glichkeiten in universit{\"a}ren Lehrveranstaltungen und eine prototypische Integration in eine koaktive Lern- und Arbeitsumgebung vor.},
language = {de}
}
@phdthesis{Mueller2016,
author = {Mueller, Stefanie},
title = {Interacting with personal fabrication devices},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-100908},
school = {Universit{\"a}t Potsdam},
pages = {xxi, 108},
year = {2016},
abstract = {Personal fabrication tools, such as 3D printers, are on the way of enabling a future in which non-technical users will be able to create custom objects. However, while the hardware is there, the current interaction model behind existing design tools is not suitable for non-technical users. Today, 3D printers are operated by fabricating the object in one go, which tends to take overnight due to the slow 3D printing technology. Consequently, the current interaction model requires users to think carefully before printing as every mistake may imply another overnight print. Planning every step ahead, however, is not feasible for non-technical users as they lack the experience to reason about the consequences of their design decisions. In this dissertation, we propose changing the interaction model around personal fabrication tools to better serve this user group. We draw inspiration from personal computing and argue that the evolution of personal fabrication may resemble the evolution of personal computing: Computing started with machines that executed a program in one go before returning the result to the user. By decreasing the interaction unit to single requests, turn-taking systems such as the command line evolved, which provided users with feedback after every input. Finally, with the introduction of direct-manipulation interfaces, users continuously interacted with a program receiving feedback about every action in real-time. In this dissertation, we explore whether these interaction concepts can be applied to personal fabrication as well. We start with fabricating an object in one go and investigate how to tighten the feedback-cycle on an object-level: We contribute a method called low-fidelity fabrication, which saves up to 90\% fabrication time by creating objects as fast low-fidelity previews, which are sufficient to evaluate key design aspects. Depending on what is currently being tested, we propose different conversions that enable users to focus on different parts: faBrickator allows for a modular design in the early stages of prototyping; when users move on WirePrint allows quickly testing an object's shape, while Platener allows testing an object's technical function. We present an interactive editor for each technique and explain the underlying conversion algorithms. By interacting on smaller units, such as a single element of an object, we explore what it means to transition from systems that fabricate objects in one go to turn-taking systems. We start with a 2D system called constructable: Users draw with a laser pointer onto the workpiece inside a laser cutter. The drawing is captured with an overhead camera. As soon as the the user finishes drawing an element, such as a line, the constructable system beautifies the path and cuts it--resulting in physical output after every editing step. We extend constructable towards 3D editing by developing a novel laser-cutting technique for 3D objects called LaserOrigami that works by heating up the workpiece with the defocused laser until the material becomes compliant and bends down under gravity. While constructable and LaserOrigami allow for fast physical feedback, the interaction is still best described as turn-taking since it consists of two discrete steps: users first create an input and afterwards the system provides physical output. By decreasing the interaction unit even further to a single feature, we can achieve real-time physical feedback: Input by the user and output by the fabrication device are so tightly coupled that no visible lag exists. This allows us to explore what it means to transition from turn-taking interfaces, which only allow exploring one option at a time, to direct manipulation interfaces with real-time physical feedback, which allow users to explore the entire space of options continuously with a single interaction. We present a system called FormFab, which allows for such direct control. FormFab is based on the same principle as LaserOrigami: It uses a workpiece that when warmed up becomes compliant and can be reshaped. However, FormFab achieves the reshaping not based on gravity, but through a pneumatic system that users can control interactively. As users interact, they see the shape change in real-time. We conclude this dissertation by extrapolating the current evolution into a future in which large numbers of people use the new technology to create objects. We see two additional challenges on the horizon: sustainability and intellectual property. We investigate sustainability by demonstrating how to print less and instead patch physical objects. We explore questions around intellectual property with a system called Scotty that transfers objects without creating duplicates, thereby preserving the designer's copyright.},
language = {en}
}
@phdthesis{Trapp2013,
author = {Trapp, Matthias},
title = {Interactive rendering techniques for focus+context visualization of 3D geovirtual environments},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-66824},
school = {Universit{\"a}t Potsdam},
year = {2013},
abstract = {This thesis introduces a collection of new real-time rendering techniques and applications for focus+context visualization of interactive 3D geovirtual environments such as virtual 3D city and landscape models. These environments are generally characterized by a large number of objects and are of high complexity with respect to geometry and textures. For these reasons, their interactive 3D rendering represents a major challenge. Their 3D depiction implies a number of weaknesses such as occlusions, cluttered image contents, and partial screen-space usage. To overcome these limitations and, thus, to facilitate the effective communication of geo-information, principles of focus+context visualization can be used for the design of real-time 3D rendering techniques for 3D geovirtual environments (see Figure). In general, detailed views of a 3D geovirtual environment are combined seamlessly with abstracted views of the context within a single image. To perform the real-time image synthesis required for interactive visualization, dedicated parallel processors (GPUs) for rasterization of computer graphics primitives are used. For this purpose, the design and implementation of appropriate data structures and rendering pipelines are necessary. The contribution of this work comprises the following five real-time rendering methods: • The rendering technique for 3D generalization lenses enables the combination of different 3D city geometries (e.g., generalized versions of a 3D city model) in a single image in real time. The method is based on a generalized and fragment-precise clipping approach, which uses a compressible, raster-based data structure. It enables the combination of detailed views in the focus area with the representation of abstracted variants in the context area. • The rendering technique for the interactive visualization of dynamic raster data in 3D geovirtual environments facilitates the rendering of 2D surface lenses. It enables a flexible combination of different raster layers (e.g., aerial images or videos) using projective texturing for decoupling image and geometry data. Thus, various overlapping and nested 2D surface lenses of different contents can be visualized interactively. • The interactive rendering technique for image-based deformation of 3D geovirtual environments enables the real-time image synthesis of non-planar projections, such as cylindrical and spherical projections, as well as multi-focal 3D fisheye-lenses and the combination of planar and non-planar projections. • The rendering technique for view-dependent multi-perspective views of 3D geovirtual environments, based on the application of global deformations to the 3D scene geometry, can be used for synthesizing interactive panorama maps to combine detailed views close to the camera (focus) with abstract views in the background (context). This approach reduces occlusions, increases the usage the available screen space, and reduces the overload of image contents. • The object-based and image-based rendering techniques for highlighting objects and focus areas inside and outside the view frustum facilitate preattentive perception. The concepts and implementations of interactive image synthesis for focus+context visualization and their selected applications enable a more effective communication of spatial information, and provide building blocks for design and development of new applications and systems in the field of 3D geovirtual environments.},
language = {en}
}
@phdthesis{Weigend2007,
author = {Weigend, Michael},
title = {Intuitive Modelle der Informatik},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-940793-08-9},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-15787},
school = {Universit{\"a}t Potsdam},
pages = {331},
year = {2007},
abstract = {Intuitive Modelle der Informatik sind gedankliche Vorstellungen {\"u}ber informatische Konzepte, die mit subjektiver Gewissheit verbunden sind. Menschen verwenden sie, wenn sie die Arbeitsweise von Computerprogrammen nachvollziehen oder anderen erkl{\"a}ren, die logische Korrektheit eines Programms pr{\"u}fen oder in einem kreativen Prozess selbst Programme entwickeln. Intuitive Modelle k{\"o}nnen auf verschiedene Weise repr{\"a}sentiert und kommuniziert werden, etwa verbal-abstrakt, durch ablauf- oder strukturorientierte Abbildungen und Filme oder konkrete Beispiele. Diskutiert werden in dieser Arbeit grundlegende intuitive Modelle f{\"u}r folgende inhaltliche Aspekte einer Programmausf{\"u}hrung: Allokation von Aktivit{\"a}t bei einer Programmausf{\"u}hrung, Benennung von Entit{\"a}ten, Daten, Funktionen, Verarbeitung, Kontrollstrukturen zur Steuerung von Programml{\"a}ufen, Rekursion, Klassen und Objekte. Mit Hilfe eines Systems von Online-Spielen, der Python Visual Sandbox, werden die psychische Realit{\"a}t verschiedener intuitiver Modelle bei Programmieranf{\"a}ngern nachgewiesen und fehlerhafte Anwendungen (Fehlvorstellungen) identifiziert.},
language = {de}
}
@article{HurtienneSchroederSpannagel2015,
author = {Hurtienne, Dominik and Schroeder, Ulrik and Spannagel, Christian},
title = {IT EnGAGES!},
series = {HDI 2014 : Gestalten von {\"U}berg{\"a}ngen},
volume = {2015},
journal = {HDI 2014 : Gestalten von {\"U}berg{\"a}ngen},
number = {9},
editor = {Schwill, Andreas and Schubert, Sigrid},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-80258},
pages = {27 -- 43},
year = {2015},
abstract = {Durch den Einsatz von Spielen und Spielelementen in Lernkontexten wird versucht, Lernende zur Besch{\"a}ftigung mit den Lerninhalten zu motivieren. Spielerische Elemente haben allerdings nicht nur positive motivationale Effekte: Sie k{\"o}nnen sich beispielsweise negativ auf die intrinsische Motivation auswirken, und auch nicht jeder Lernende spielt gerne. Um negativen Einfl{\"u}ssen von Gamification entgegenzuwirken, wurde ein Toolkit f{\"u}r adaptierbare Lernumgebungen entwickelt. Damit erzeugte Lernumgebungen erlauben es Studierenden, den Grad der Gamification selbst zu bestimmen, indem Spielelemente an- und abgeschaltet werden. Im Rahmen einer Anf{\"a}ngerprogrammiervorlesung wurden Lernspielaufgaben aus den existierenden, optionalen interaktiven eTests entwickelt und Studierenden als zus{\"a}tzliche Lerngelegenheit angeboten. Eine erste explorative Studie best{\"a}tigt die Vermutung, dass die Akzeptanz des adaptierbaren Lernspiels sehr hoch ist, es aber dennoch Studierende gibt, welche die Lernumgebung ohne Spielelemente durcharbeiten. Somit bietet adaptierbare Gamification verschiedenen Studierenden die M{\"o}glichkeit, sich zus{\"a}tzliche motivationale Anreize durch Zuschalten von Spielelementen zu verschaffen, ohne dabei zum Spielen „gen{\"o}tigt" zu werden.},
language = {de}
}
@misc{Kujath2011,
author = {Kujath, Bertold},
title = {Keine Angst vor Informatikproblemen},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-150-9},
doi = {10.25932/publishup-32638},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-326380},
pages = {1 DVD-Video (ca. 33 Min.) : farb. ; 12 cm},
year = {2011},
abstract = {Dieses Lehrvideo zeigt aus der Perspektive einer {\"U}bertischkamera den fiktiven informatischen Hochleister Tom bei der Bearbeitung eines schwierigen F{\"a}rbeproblems. Dabei kann man die fortlaufend von ihm angefertigten Skizzen beobachten und seine Gedankeng{\"a}nge genau verfolgen. Denn dieser Probleml{\"o}ser arbeitet unter lautem Denken, d. h. er spricht alle seine Gedankeng{\"a}nge laut aus. Man kann zuschauen, wie Tom zun{\"a}chst die Aufgabe analysiert und die dadurch gewonnenen Erkenntnisse in der anschließenden Problembearbeitung gewinnbringend einsetzt. Der Zuschauer wird dabei aber nicht allein gelassen. An markanten Stellen wird das Video unterbrochen und Toms zur{\"u}ckliegende Aktivit{\"a}ten mit animierten Bildsequenzen vertiefend erl{\"a}utert. Schwache Probleml{\"o}ser k{\"o}nnen so die in Unterricht oder Vorlesung vermittelten Kenntnisse {\"u}ber informatische Probleml{\"o}semethoden vertiefen und deren Anwendung durch einen starken Probleml{\"o}ser beispielhaft miterleben. Entstanden ist dieses Video aus einer Vergleichsstudie mit starken und schwachen Probleml{\"o}sern. Die effizienten Methoden der Hochleister wurden didaktisch aufgearbeitet und zu einem modellhaften Probleml{\"o}seprozess zusammengesetzt. Der wissenschaftliche Hintergrund des Lehrvideos wird durch eine als Bildergeschichte erz{\"a}hlte Rahmenhandlung verdeutlicht. Bei Erstsemesterstudenten der Informatik, denen dieses Video zur Bewertung vorgespielt wurde, fand dieses Konzept große Zustimmung. Tenor: Unterhaltsam und lehrreich zugleich.},
subject = {Graphf{\"a}rbung},
language = {de}
}
@article{PrzybyllaRomeike2015,
author = {Przybylla, Mareen and Romeike, Ralf},
title = {Key Competences with Physical Computing},
series = {KEYCIT 2014 - Key Competencies in Informatics and ICT},
journal = {KEYCIT 2014 - Key Competencies in Informatics and ICT},
number = {7},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-82904},
pages = {351 -- 361},
year = {2015},
abstract = {Physical computing covers the design and realization of interactive objects and installations and allows students to develop concrete, tangible products of the real world that arise from the learners' imagination. This way, constructionist learning is raised to a level that enables students to gain haptic experience and thereby concretizes the virtual. In this paper the defining characteristics of physical computing are described. Key competences to be gained with physical computing will be identified.},
language = {en}
}
@inproceedings{CurzonKalasSchubertetal.2015,
author = {Curzon, Paul and Kalas, Ivan and Schubert, Sigrid and Schaper, Niclas and Barnes, Jan and Kennewell, Steve and Br{\"o}ker, Kathrin and Kastens, Uwe and Magenheim, Johannes and Dagiene, Valentina and Stupuriene, Gabriele and Ellis, Jason Brent and Abreu-Ellis, Carla Reis and Grillenberger, Andreas and Romeike, Ralf and Haugsbakken, Halvdan and Jones, Anthony and Lewin, Cathy and McNicol, Sarah and Nelles, Wolfgang and Neugebauer, Jonas and Ohrndorf, Laura and Schaper, Niclas and Schubert, Sigrid and Opel, Simone and Kramer, Matthias and Trommen, Michael and Pottb{\"a}cker, Florian and Ilaghef, Youssef and Passig, David and Tzuriel, David and Kedmi, Ganit Eshel and Saito, Toshinori and Webb, Mary and Weigend, Michael and Bottino, Rosa and Chioccariello, Augusto and Christensen, Rhonda and Knezek, Gerald and Gioko, Anthony Maina and Angondi, Enos Kiforo and Waga, Rosemary and Ohrndorf, Laura and Or-Bach, Rachel and Preston, Christina and Younie, Sarah and Przybylla, Mareen and Romeike, Ralf and Reynolds, Nicholas and Swainston, Andrew and Bendrups, Faye and Sysło, Maciej M. and Kwiatkowska, Anna Beata and Zieris, Holger and Gerstberger, Herbert and M{\"u}ller, Wolfgang and B{\"u}chner, Steffen and Opel, Simone and Schiller, Thomas and Wegner, Christian and Zender, Raphael and Lucke, Ulrike and Diethelm, Ira and Syrbe, J{\"o}rn and Lai, Kwok-Wing and Davis, Niki and Eickelmann, Birgit and Erstad, Ola and Fisser, Petra and Gibson, David and Khaddage, Ferial and Knezek, Gerald and Micheuz, Peter and Kloos, Carlos Delgado},
title = {KEYCIT 2014},
editor = {Brinda, Torsten and Reynolds, Nicholas and Romeike, Ralf and Schwill, Andreas},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-292-6},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-70325},
pages = {438},
year = {2015},
abstract = {In our rapidly changing world it is increasingly important not only to be an expert in a chosen field of study but also to be able to respond to developments, master new approaches to solving problems, and fulfil changing requirements in the modern world and in the job market. In response to these needs key competencies in understanding, developing and using new digital technologies are being brought into focus in school and university programmes. The IFIP TC3 conference "KEYCIT - Key Competences in Informatics and ICT (KEYCIT 2014)" was held at the University of Potsdam in Germany from July 1st to 4th, 2014 and addressed the combination of key competencies, Informatics and ICT in detail. The conference was organized into strands focusing on secondary education, university education and teacher education (organized by IFIP WGs 3.1 and 3.3) and provided a forum to present and to discuss research, case studies, positions, and national perspectives in this field.},
language = {en}
}
@article{AbkeSchwirtlichSedelmaier2013,
author = {Abke, J{\"o}rg and Schwirtlich, Vincent and Sedelmaier, Yvonne},
title = {Kompetenzf{\"o}rderung im Software Engineering durch ein mehrstufiges Lehrkonzept im Studiengang Mechatronik},
series = {Commentarii informaticae didacticae : (CID)},
journal = {Commentarii informaticae didacticae : (CID)},
number = {5},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-64899},
pages = {79 -- 84},
year = {2013},
abstract = {Dieser Beitrag stellt das Lehr-Lern-Konzept zur Kompetenzf{\"o}rderung im Software Engineering im Studiengang Mechatronik der Hochschule Aschaffenburg dar. Dieses Konzept ist mehrstufig mit Vorlesungs-, Seminar- und Projektsequenzen. Dabei werden Herausforderungen und Verbesserungspotentiale identifiziert und dargestellt. Abschließend wird ein {\"U}berblick gegeben, wie im Rahmen eines gerade gestarteten Forschungsprojektes Lehr-Lernkonzepte weiterentwickelt werden k{\"o}nnen.},
language = {de}
}
@phdthesis{Knoepfel2004,
author = {Kn{\"o}pfel, Andreas},
title = {Konzepte der Beschreibung interaktiver Systeme},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-2898},
school = {Universit{\"a}t Potsdam},
year = {2004},
abstract = {Interaktive System sind dynamische Systeme mit einem zumeist informationellen Kern, die {\"u}ber eine Benutzungsschnittstelle von einem oder mehreren Benutzern bedient werden k{\"o}nnen. Grundlage f{\"u}r die Benutzung interaktiver Systeme ist das Verst{\"a}ndnis von Zweck und Funktionsweise. Allein aus Form und Gestalt der Benutzungsschnittstelle ergibt sich ein solches Verst{\"a}ndnis nur in einfachen F{\"a}llen. Mit steigender Komplexit{\"a}t ist daher eine verst{\"a}ndliche Beschreibung solcher Systeme f{\"u}r deren Entwicklung und Benutzung unverzichtbar. Abh{\"a}ngig von ihrem Zweck variieren die Formen vorgefundener Beschreibungen in der Literatur sehr stark. Ausschlaggebend f{\"u}r die Verst{\"a}ndlichkeit einer Beschreibung ist jedoch prim{\"a}r die ihr zugrundeliegende Begriffswelt. Zur Beschreibung allgemeiner komplexer diskreter Systeme - aufbauend auf einer getrennten Betrachtung von Aufbau-, Ablauf- und Wertestrukturen - existiert eine bew{\"a}hrte Begriffswelt. Eine Spezialisierung dieser Begriffs- und Vorstellungswelt, die den unterschiedlichen Betrachtungsebenen interaktiver Systeme gerecht wird und die als Grundlage beliebiger Beschreibungsans{\"a}tze interaktiver Systeme dienen kann, gibt es bisher nicht. Ziel dieser Arbeit ist die Bereitstellung einer solchen Begriffswelt zur effizienten Kommunikation der Strukturen interaktiver Systeme. Dadurch soll die Grundlage f{\"u}r eine sinnvolle Erg{\"a}nzung bestehender Beschreibungs- und Entwicklungsans{\"a}tze geschaffen werden. Prinzipien der Gestaltung von Benutzungsschnittstellen, Usability- oder Ergonomiebetrachtungen stehen nicht im Mittelpunkt der Arbeit. Ausgehend von der informationellen Komponente einer Benutzungsschnittstelle werden drei Modellebenen abgegrenzt, die bei der Betrachtung eines interaktiven Systems zu unterscheiden sind. Jede Modellebene ist durch eine typische Begriffswelt gekennzeichnet, die ihren Ursprung in einer aufbauverwurzelten Vorstellung hat. Der durchg{\"a}ngige Bezug auf eine Systemvorstellung unterscheidet diesen Ansatz von dem bereits bekannten Konzept der Abgrenzung unterschiedlicher Ebenen verschiedenartiger Entwurfsentscheidungen. Die Fundamental Modeling Concepts (FMC) bilden dabei die Grundlage f{\"u}r die Findung und die Darstellung von Systemstrukturen. Anhand bestehender Systembeschreibungen wird gezeigt, wie die vorgestellte Begriffswelt zur Modellfindung genutzt werden kann. Dazu wird eine repr{\"a}sentative Auswahl vorgefundener Systembeschreibungen aus der einschl{\"a}gigen Literatur daraufhin untersucht, in welchem Umfang durch sie die Vorstellungswelt dynamischer Systeme zum Ausdruck kommt. Defizite in der urspr{\"u}nglichen Darstellung werden identifiziert. Anhand von Alternativmodellen zu den betrachteten Systemen wird der Nutzen der vorgestellten Begriffswelt und Darstellungsweise demonstriert.},
subject = {Systementwurf},
language = {de}
}
@misc{Kuntzsch2015,
type = {Master Thesis},
author = {Kuntzsch, Christian},
title = {Konzeption und Implementierung eines multimodalen Campusroutenplaners am Beispiel der Universit{\"a}t Potsdam},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-77467},
school = {Universit{\"a}t Potsdam},
pages = {XIV, 86},
year = {2015},
abstract = {Die regelm{\"a}ßige Navigation durch den Raum geh{\"o}rt f{\"u}r Studenten der Universit{\"a}t Potsdam zum Alltag. Man m{\"o}chte, unabh{\"a}ngig vom Fortbewegungsmittel, schnell und sicher von zu Hause zum H{\"o}rsaal oder Seminargeb{\"a}ude. Eine umfassende Navigationshilfe, die alle Transportmodi verbindet, wird daf{\"u}r verlangt. Das Ziel dieser Arbeit besteht darin, ein Konzept f{\"u}r einen multimodalen Routenplaner zu entwickeln, der es Studenten und G{\"a}sten der Universit{\"a}t Potsdam erm{\"o}glicht, sich zwischen den dezentral gelegenen Campusstandorten zu bewegen - egal ob mit Bus und Bahn, dem Auto, Fahrrad oder zu Fuß. Die Implementierung erfolgt ausschließlich auf Grundlage freier Daten und freier, quelloffener Software (FOSS), die f{\"u}r diesen Zweck aufbereitet werden. Ergebnis ist eine webbasierte Applikation, die {\"u}ber eine Entwicklerschnittstelle (API) in andere Projekte eingebunden werden kann.},
language = {de}
}
@misc{Ohme2003,
type = {Master Thesis},
author = {Ohme, Sebastian},
title = {Konzeption von Dokumentenservern f{\"u}r Digitale Bibliotheken im Hinblick auf Langzeitarchivierung und Retrieval},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-5880},
school = {Universit{\"a}t Potsdam},
year = {2003},
abstract = {Entwickelt wird ein Dokument Management System zur elektronischen, Client-Server-basierten Publikation und Langzeitarchivierung von Hochschulschriften f{\"u}r die Universit{\"a}tsbibliothek Potsdam. Der zu konzipierende Dokumentenserver muss den bibliothekarischen Anforderungen im Hinblick auf die Sicherung von Authentizit{\"a}t und Integrit{\"a}t des Servers und der einzelnen Textdokumente entsprechen. Eine Analyse der Eignung verbreiteter Dateiformate zur dauerhaften Speicherung unter Ber{\"u}cksichtigung von Verf{\"u}gbarkeit, Strukturierbarkeit, Konvertierbarkeit und Austauschbarkeit sowie Recherchierbarkeit erbringt eine langfristig anzustrebende Pr{\"a}ferenz f{\"u}r XML als Archivierungs- und Rechercheformat sowie PDF und/oder HTML als Pr{\"a}sentationsformate. Die Formalerfassung erfolgt {\"u}ber die Anreicherung des Dokumentes mit Metadaten nach dem DC qualified Standard, die in einer Datenbank strukturiert abgelegt sind. Der dauerhafte Zugang zur Publikation kann durch Verwendung einer zitierf{\"a}higen URN (Persistent Identifier) gesichert werden. Bestehende Archivierungssysteme werden untersucht und auf Vereinbarkeit mit den lokalen Bed{\"u}rfnissen gepr{\"u}ft. Ein Workflow f{\"u}r die Anlieferung von Dokument und beschreibenden Metadaten durch den Autor und die weitere Bearbeitung durch die Bibliothek wird erarbeitet und die technische Umsetzung mittels Perl, HTML, XML und einer MS Access Datenbank beschrieben. Der Dokumentenserver erm{\"o}glicht performantes Retrieval und ist als Dataprovider mit einer OAI-Schnittstelle f{\"u}r den weltweiten, standardisierten Datenaustausch ausgestattet. Das System kann in wissenschaftlichen Informationseinrichtungen als Internet- oder Intranet-Repositorium eingesetzt werden. (Fremdreferat)},
subject = {Elektronisches Publizieren},
language = {de}
}
@phdthesis{Groene2004,
author = {Gr{\"o}ne, Bernhard},
title = {Konzeptionelle Patterns und ihre Darstellung},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-2302},
school = {Universit{\"a}t Potsdam},
pages = {vii ; 120},
year = {2004},
abstract = {Zur Beherrschung großer Systeme, insbesondere zur Weitergabe und Nutzung von Erfahrungswissen in der fr{\"u}hen Entwurfs- und Planungsphase, ben{\"o}tigt man Abstraktionen f{\"u}r deren Strukturen. Trennt man Software- von Systemstrukturen, kann man mit letzteren Systeme auf ausreichend hohem Abstraktionsgrad beschreiben.Software-Patterns dienen dazu, Erfahrungswissen bez{\"u}glich programmierter Systeme strukturiert weiterzugeben. Dabei wird unterschieden zwischen Idiomen, die sich auf L{\"o}sungen mit einer bestimmten Programmiersprache beziehen, Design-Patterns, die nur einen kleinen Teil des Programms betreffen und Architektur-Patterns, deren Einfluss {\"u}ber einen gr{\"o}ßeren Teil oder gar das komplette Programm reicht. Eine Untersuchung von existierenden Patterns zeigt, dass deren Konzepte n{\"u}tzlich zum Finden von Systemstrukturen sind. Die grafische Darstellung dieser Patterns ist dagegen oft auf Software-Strukturen eingeschr{\"a}nkt und ist f{\"u}r die Vermittlung von Erfahrungen zum Finden von Systemstrukturen meist nicht geeignet. Daher wird die Kategorie der konzeptionellen Patterns mit einer darauf abgestimmten grafischen Darstellungsform vorgeschlagen, bei denen Problem und L{\"o}sungsvorschlag im Bereich der Systemstrukturen liegen. Sie betreffen informationelle Systeme, sind aber nicht auf L{\"o}sungen mit Software beschr{\"a}nkt. Die Systemstrukturen werden grafisch dargestellt, wobei daf{\"u}r die Fundamental Modeling Concepts (FMC) verwendet werden, die zur Darstellung von Systemstrukturen entwickelt wurden.},
language = {de}
}
@article{Gebhardt2016,
author = {Gebhardt, Kai},
title = {Kooperative und kompetenzorientierte {\"U}bungen in der Softwaretechnik},
series = {Commentarii informaticae didacticae (CID)},
journal = {Commentarii informaticae didacticae (CID)},
number = {10},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-376-3},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-94867},
pages = {95 -- 98},
year = {2016},
abstract = {Die Unterrichtsmethode Stationsarbeit kann verwendet werden, um Individualisierung und Differenzierung im Lernprozess zu erm{\"o}glichen. Dieser Beitrag schl{\"a}gt Aufgabenformate vor, die in einer Stationsarbeit {\"u}ber das Klassendiagramm aus der Unified Modeling Language verwendet werden k{\"o}nnen. Die Aufgabenformate wurden bereits mit Studierenden erprobt.},
language = {de}
}
@article{LaroqueSchulteUrban2010,
author = {Laroque, Christoph and Schulte, Jonas and Urban, Diana},
title = {KoProV},
series = {Commentarii informaticae didacticae : (CID)},
journal = {Commentarii informaticae didacticae : (CID)},
number = {4},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-64445},
pages = {99 -- 105},
year = {2010},
abstract = {In der universit{\"a}ren Lehre {\"a}ndert sich der Leitgedanke von einer qualifikationsorientierten hin zu einer kompetenzorientierten Ausbildung. Der Begriff Kompetenz l{\"a}sst sich dabei grob in die fachlichen und die {\"u}berfachlichen Kompetenzen unterteilen. Insbesondere die Vermittlung von Schl{\"u}sselqualifikationen hat in der Lehre von naturwissenschaftlichen Fachrichtungen nur unzureichend Einzug erhalten. W{\"a}hrend der klassische Vorlesungsbetrieb auf den Erwerb von Fachkompetenz zielt, stoßen ausschließlich projektorientierte Veranstaltungen schnell an ihre Grenzen hinsichtlich der Teilnehmergr{\"o}ße oder Umfang der Lerninhalte. Um auf geeignete Art und Weise den Erwerb von {\"u}berfachlichen Kompetenzen zu erm{\"o}glichen, bedarf es neuer didaktischer Konzepte, die eine engere Verkn{\"u}pfung von klassischen Vorlesungen und dem projektorientierten Lernen vorsehen. In diesem Sinne versucht der skizzierte Ansatz der koordinierten Projektvorlesung(KoProV) Wissensvermittlung im Rahmen von Vorlesungseinheiten mit koordinierten Praxisphasen in Teilgruppen zu verbinden. F{\"u}r eine erfolgreiche Durchf{\"u}hrung und Erarbeitung des begleitenden Praxisprojektes durch mehrere Teilgruppen sind organisatorische und technische Randbedingungen zu beachten.},
language = {de}
}
@phdthesis{Bickel2008,
author = {Bickel, Steffen},
title = {Learning under differing training and test distributions},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-33331},
school = {Universit{\"a}t Potsdam},
year = {2008},
abstract = {One of the main problems in machine learning is to train a predictive model from training data and to make predictions on test data. Most predictive models are constructed under the assumption that the training data is governed by the exact same distribution which the model will later be exposed to. In practice, control over the data collection process is often imperfect. A typical scenario is when labels are collected by questionnaires and one does not have access to the test population. For example, parts of the test population are underrepresented in the survey, out of reach, or do not return the questionnaire. In many applications training data from the test distribution are scarce because they are difficult to obtain or very expensive. Data from auxiliary sources drawn from similar distributions are often cheaply available. This thesis centers around learning under differing training and test distributions and covers several problem settings with different assumptions on the relationship between training and test distributions-including multi-task learning and learning under covariate shift and sample selection bias. Several new models are derived that directly characterize the divergence between training and test distributions, without the intermediate step of estimating training and test distributions separately. The integral part of these models are rescaling weights that match the rescaled or resampled training distribution to the test distribution. Integrated models are studied where only one optimization problem needs to be solved for learning under differing distributions. With a two-step approximation to the integrated models almost any supervised learning algorithm can be adopted to biased training data. In case studies on spam filtering, HIV therapy screening, targeted advertising, and other applications the performance of the new models is compared to state-of-the-art reference methods.},
language = {en}
}
@article{Kujath2016,
author = {Kujath, Bertold},
title = {Lernwirksamkeits- und Zielgruppenanalyse f{\"u}r ein Lehrvideo zum informatischen Probleml{\"o}sen},
series = {Commentarii informaticae didacticae (CID)},
journal = {Commentarii informaticae didacticae (CID)},
number = {10},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-376-3},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-94797},
pages = {25 -- 39},
year = {2016},
abstract = {Aus einer Vergleichsstudie mit starken und schwachen Probleml{\"o}sern konnten Erkenntnisse {\"u}ber die effizienten Herangehensweisen von Hochleistern an Informatikprobleme gewonnen werden. Diese Erkenntnisse wurden in einem Lehrvideo zum informatischen Probleml{\"o}sen didaktisch aufgearbeitet, sodass Lernenden der Einsatz von Baumstrukturen und Rekursion im konkreten Kontext gezeigt werden kann. Nun wurde die tats{\"a}chliche Lernwirksamkeit des Videos sowie die Definition der Zielgruppe in einer Vergleichsstudie mit 66 Studienanf{\"a}ngern {\"u}berpr{\"u}ft.},
language = {de}
}
@article{DiethelmSyrbe2015,
author = {Diethelm, Ira and Syrbe, J{\"o}rn},
title = {Let's talk about CS!},
series = {KEYCIT 2014 - Key Competencies in Informatics and ICT},
journal = {KEYCIT 2014 - Key Competencies in Informatics and ICT},
number = {7},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-82983},
pages = {411 -- 414},
year = {2015},
abstract = {To communicate about a science is the most important key competence in education for any science. Without communication we cannot teach, so teachers should reflect about the language they use in class properly. But the language students and teachers use to communicate about their CS courses is very heterogeneous, inconsistent and deeply influenced by tool names. There is a big lack of research and discussion in CS education regarding the terminology and the role of concepts and tools in our science. We don't have a consistent set of terminology that we agree on to be helpful for learning our science. This makes it nearly impossible to do research on CS competencies as long as we have not agreed on the names we use to describe these. This workshop intends to provide room to fill with discussion and first ideas for future research in this field.},
language = {en}
}
@article{BoehneKreitzKnobelsdorf2016,
author = {B{\"o}hne, Sebastian and Kreitz, Christoph and Knobelsdorf, Maria},
title = {Mathematisches Argumentieren und Beweisen mit dem Theorembeweiser Coq},
series = {Commentarii informaticae didacticae (CID)},
journal = {Commentarii informaticae didacticae (CID)},
number = {10},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-376-3},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-94824},
pages = {69 -- 80},
year = {2016},
abstract = {Informatik-Studierende haben in der Mehrzahl Schwierigkeiten, einen Einstieg in die Theoretische Informatik zu finden und die Leistungsanforderungen in den Endklausuren der zugeh{\"o}rigen Lehrveranstaltungen zu erf{\"u}llen. Wir argumentieren, dass dieser Symptomatik mangelnde Kompetenzen im Umgang mit abstrakten und stark formalisierten Themeninhalten zugrunde liegen und schlagen vor, einen Beweisassistenten als interaktives Lernwerkzeug in der Eingangslehre der Theoretischen Informatik zu nutzen, um entsprechende Kompetenzen zu st{\"a}rken.},
language = {de}
}
@article{Keil2009,
author = {Keil, Reinhard},
title = {Medi@Thing},
series = {Commentarii informaticae didacticae : (CID)},
journal = {Commentarii informaticae didacticae : (CID)},
number = {1},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-29611},
pages = {9 -- 24},
year = {2009},
abstract = {In vielen Bildungsbereichen verschieben sich gegenw{\"a}rtig die Akzente von einer qualifikationsorientierten zu einer st{\"a}rker kompetenzorientierten Ausbildung. Der Begriff der Kompetenz zielt dabei darauf ab, das Aneignen von Wissen auf Vorrat zugunsten des Erwerbs allgemeiner Kompetenzen beispielsweise zur eigenst{\"a}ndigen Aneignung von Wissen zu verschieben. Schl{\"u}sselqualifikationen geraten dabei zunehmend auch f{\"u}r die Ausbildung von Ingenieuren und Informatikern ins Blickfeld. Der kooperative und erw{\"a}gende Umgang mit Wissensvielfalt wird in einer Informationsgesellschaft mit ihrer schnellen und verteilten Aufbereitung von Wissen zur Herausforderung. Der Beitrag skizziert die damit verbundenen Anforderungen und stellt mit dem Konzept des Medi@Thing einen Ansatz vor, der die Umsetzung solcher Anforderungen im Rahmen der universit{\"a}ren Informatikausbildung erm{\"o}glicht. Ein zentrales Moment dieses Ansatzes ist die ko-aktive Wissensarbeit in virtuellen R{\"a}umen. Erste Erfahrungen zeigen, dass das Konzept von Studierenden angenommen wird. Es wird jedoch auch deutlich, dass f{\"u}r das Gelingen bestimmte organisatorische und technische Randbedingungen zu beachten sind.},
language = {de}
}
@article{EngbringKlar2015,
author = {Engbring, Dieter and Klar, Tilman-Mathies},
title = {Medienbildung mit Informatik-Anteilen!?},
series = {HDI 2014 : Gestalten von {\"U}berg{\"a}ngen},
volume = {2015},
journal = {HDI 2014 : Gestalten von {\"U}berg{\"a}ngen},
number = {9},
editor = {Schubert, Sigrid and Schwill, Andreas},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-84693},
pages = {125 -- 142},
year = {2015},
abstract = {Auf der Grundlage der Planung, Durchf{\"u}hrung, Evaluation und Revision eines gemeinsamen Seminars von Medienp{\"a}dagogik und Didaktik der Informatik stellen wir in diesem Aufsatz dar, wo die Defizite klassischer Medienbildung in Bezug auf digitale bzw. interaktive Medien liegen und welche Inhalte der Informatik f{\"u}r Studierende aller Lehr{\"a}mter - im allgemeinbildenden Sinne - aus dieser Perspektive relevant erscheinen.},
language = {de}
}
@article{PrestonYounie2015,
author = {Preston, Christina and Younie, Sarah},
title = {Mentoring in a Digital World},
series = {KEYCIT 2014 - Key Competencies in Informatics and ICT},
journal = {KEYCIT 2014 - Key Competencies in Informatics and ICT},
number = {7},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-82895},
pages = {343 -- 350},
year = {2015},
abstract = {This paper focuses on the results of the evaluation of the first pilot of an e-mentoring unit designed by the Hands-On ICT consortium, funded by the EU LLL programme. The overall aim of this two-year activity is to investigate the value for professional learning of Massive Online Open Courses (MOOCs) and Community Online Open Courses (COOCs) in the context of a 'community of practice'. Three units in the first pilot covered aspects of using digital technologies to develop creative thinking skills. The findings in this paper relate to the fourth unit about e-mentoring, a skill that was important to delivering the course content in the other three units. Findings about the e-mentoring unit included: the students' request for detailed profiles so that participants can get to know each other; and, the need to reconcile the different interpretations of e-mentoring held by the participants when the course begins. The evaluators concluded that the major issues were that: not all professional learners would self-organise and network; and few would wish to mentor their colleagues voluntarily. Therefore, the e-mentoring issues will need careful consideration in pilots two and three to identify how e-mentoring will be organised.},
language = {en}
}
@phdthesis{Schrape2023,
author = {Schrape, Oliver},
title = {Methodology for standard cell-based design and implementation of reliable and robust hardware systems},
doi = {10.25932/publishup-58932},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-589326},
school = {Universit{\"a}t Potsdam},
pages = {xi, 181},
year = {2023},
abstract = {Reliable and robust data processing is one of the hardest requirements for systems in fields such as medicine, security, automotive, aviation, and space, to prevent critical system failures caused by changes in operating or environmental conditions. In particular, Signal Integrity (SI) effects such as crosstalk may distort the signal information in sensitive mixed-signal designs. A challenge for hardware systems used in the space are radiation effects. Namely, Single Event Effects (SEEs) induced by high-energy particle hits may lead to faulty computation, corrupted configuration settings, undesired system behavior, or even total malfunction. Since these applications require an extra effort in design and implementation, it is beneficial to master the standard cell design process and corresponding design flow methodologies optimized for such challenges. Especially for reliable, low-noise differential signaling logic such as Current Mode Logic (CML), a digital design flow is an orthogonal approach compared to traditional manual design. As a consequence, mandatory preliminary considerations need to be addressed in more detail. First of all, standard cell library concepts with suitable cell extensions for reliable systems and robust space applications have to be elaborated. Resulting design concepts at the cell level should enable the logical synthesis for differential logic design or improve the radiation-hardness. In parallel, the main objectives of the proposed cell architectures are to reduce the occupied area, power, and delay overhead. Second, a special setup for standard cell characterization is additionally required for a proper and accurate logic gate modeling. Last but not least, design methodologies for mandatory design flow stages such as logic synthesis and place and route need to be developed for the respective hardware systems to keep the reliability or the radiation-hardness at an acceptable level. This Thesis proposes and investigates standard cell-based design methodologies and techniques for reliable and robust hardware systems implemented in a conventional semi-conductor technology. The focus of this work is on reliable differential logic design and robust radiation-hardening-by-design circuits. The synergistic connections of the digital design flow stages are systematically addressed for these two types of hardware systems. In more detail, a library for differential logic is extended with single-ended pseudo-gates for intermediate design steps to support the logic synthesis and layout generation with commercial Computer-Aided Design (CAD) tools. Special cell layouts are proposed to relax signal routing. A library set for space applications is similarly extended by novel Radiation-Hardening-by-Design (RHBD) Triple Modular Redundancy (TMR) cells, enabling a one fault correction. Therein, additional optimized architectures for glitch filter cells, robust scannable and self-correcting flip-flops, and clock-gates are proposed. The circuit concepts and the physical layout representation views of the differential logic gates and the RHBD cells are discussed. However, the quality of results of designs depends implicitly on the accuracy of the standard cell characterization which is examined for both types therefore. The entire design flow is elaborated from the hardware design description to the layout representations. A 2-Phase routing approach together with an intermediate design conversion step is proposed after the initial place and route stage for reliable, pure differential designs, whereas a special constraining for RHBD applications in a standard technology is presented. The digital design flow for differential logic design is successfully demonstrated on a reliable differential bipolar CML application. A balanced routing result of its differential signal pairs is obtained by the proposed 2-Phase-routing approach. Moreover, the elaborated standard cell concepts and design methodology for RHBD circuits are applied to the digital part of a 7.5-15.5 MSPS 14-bit Analog-to-Digital Converter (ADC) and a complex microcontroller architecture. The ADC is implemented in an unhardened standard semiconductor technology and successfully verified by electrical measurements. The overhead of the proposed hardening approach is additionally evaluated by design exploration of the microcontroller application. Furthermore, the first obtained related measurement results of novel RHBD-∆TMR flip-flops show a radiation-tolerance up to a threshold Linear Energy Transfer (LET) of 46.1, 52.0, and 62.5 MeV cm2 mg-1 and savings in silicon area of 25-50 \% for selected TMR standard cell candidates. As a conclusion, the presented design concepts at the cell and library levels, as well as the design flow modifications are adaptable and transferable to other technology nodes. In particular, the design of hybrid solutions with integrated reliable differential logic modules together with robust radiation-tolerant circuit parts is enabled by the standard cell concepts and design methods proposed in this work.},
language = {en}
}
@article{SchwidrowskiSchmidBruecketal.2009,
author = {Schwidrowski, Kirstin and Schmid, Thilo and Br{\"u}ck, Rainer and Freischlad, Stefan and Schubert, Sigrid and Stechert, Peer},
title = {Mikrosystemverst{\"a}ndnis im Hochschulstudium - Ein praktikumsorientierter Ansatz},
series = {Commentarii informaticae didacticae : (CID)},
journal = {Commentarii informaticae didacticae : (CID)},
number = {1},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-29601},
pages = {131 -- 142},
year = {2009},
abstract = {Mit hochschuldidaktischer Forschung zur Informatik soll aus einem traditionellen Hardwarepraktikum ein attraktives Entwurfs- und Anwendungspraktikum f{\"u}r Mikrosysteme (MSE) werden, das ein unverzichtbarer Bestandteil des Informatikstudiums ist. Diese Neugestaltung der Lehre wurde aufgrund des Bologna-Prozesses und der zunehmenden Pr{\"a}senz multifunktionaler eingebetteter Mikrosysteme (EMS) im t{\"a}glichen Leben notwendig. Ausgehend von einer Lehrveranstaltungsanalyse werden Vorschl{\"a}ge f{\"u}r die Kompetenzorientierung abgeleitet. Es wird gezeigt, dass f{\"u}r eine Verfeinerung des Ansatzes ein wissenschaftlich fundiertes Verst{\"a}ndnis der erwarteten Kompetenzen erforderlich ist. F{\"u}r den aufgezeigten Forschungsbedarf werden ein Ansatz zur Beschreibung des notwendigen Mikrosystemverst{\"a}ndnisses dargestellt und Forschungsfelder zu Aspekten des Kompetenzbegriffs im Kontext der Lehrveranstaltung beschrieben.},
language = {de}
}
@article{ZoernerKoehlmannBrandt2014,
author = {Zoerner, Dietmar and K{\"o}hlmann, Wiebke and Brandt, Christopher},
title = {Mobiles spielebasiertes Lernen an historischen Lernorten},
series = {E-Learning Symposium 2014 : Mobil und vernetzt - studieren im digitalen Zeitalter ; Potsdam, 14. November 2014},
journal = {E-Learning Symposium 2014 : Mobil und vernetzt - studieren im digitalen Zeitalter ; Potsdam, 14. November 2014},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
doi = {10.25932/publishup-44235},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-442354},
pages = {53 -- 54},
year = {2014},
abstract = {Im Rahmen eines interdisziplin{\"a}ren studentischen Projekts wurde ein Framework f{\"u}r mobile pervasive Lernspiele entwickelt. Am Beispiel des historischen Lernortes Park Sanssouci wurde auf dieser Grundlage ein Lernspiel f{\"u}r Sch{\"u}lerinnen und Sch{\"u}ler implementiert. Die geplante Evaluation soll die Lernwirksamkeit von geobasierten mobilen Lernspielen messen. Dazu wird die Intensit{\"a}t des Flow-Erlebens mit einer ortsgebundenen alternativen Umsetzung verglichen.},
language = {de}
}
@phdthesis{Menzel2011,
author = {Menzel, Michael},
title = {Model-driven security in service-oriented architectures : leveraging security patterns to transform high-level security requirements to technical policies},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-59058},
school = {Universit{\"a}t Potsdam},
year = {2011},
abstract = {Service-oriented Architectures (SOA) facilitate the provision and orchestration of business services to enable a faster adoption to changing business demands. Web Services provide a technical foundation to implement this paradigm on the basis of XML-messaging. However, the enhanced flexibility of message-based systems comes along with new threats and risks. To face these issues, a variety of security mechanisms and approaches is supported by the Web Service specifications. The usage of these security mechanisms and protocols is configured by stating security requirements in security policies. However, security policy languages for SOA are complex and difficult to create due to the expressiveness of these languages. To facilitate and simplify the creation of security policies, this thesis presents a model-driven approach that enables the generation of complex security policies on the basis of simple security intentions. SOA architects can specify these intentions in system design models and are not required to deal with complex technical security concepts. The approach introduced in this thesis enables the enhancement of any system design modelling languages - for example FMC or BPMN - with security modelling elements. The syntax, semantics, and notion of these elements is defined by our security modelling language SecureSOA. The metamodel of this language provides extension points to enable the integration into system design modelling languages. In particular, this thesis demonstrates the enhancement of FMC block diagrams with SecureSOA. To enable the model-driven generation of security policies, a domain-independent policy model is introduced in this thesis. This model provides an abstraction layer for security policies. Mappings are used to perform the transformation from our model to security policy languages. However, expert knowledge is required to generate instances of this model on the basis of simple security intentions. Appropriate security mechanisms, protocols and options must be chosen and combined to fulfil these security intentions. In this thesis, a formalised system of security patterns is used to represent this knowledge and to enable an automated transformation process. Moreover, a domain-specific language is introduced to state security patterns in an accessible way. On the basis of this language, a system of security configuration patterns is provided to transform security intentions related to data protection and identity management. The formal semantics of the security pattern language enable the verification of the transformation process introduced in this thesis and prove the correctness of the pattern application. Finally, our SOA Security LAB is presented that demonstrates the application of our model-driven approach to facilitate a dynamic creation, configuration, and execution of secure Web Service-based composed applications.},
language = {en}
}
@phdthesis{Thiele2011,
author = {Thiele, Sven},
title = {Modeling biological systems with Answer Set Programming},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-59383},
school = {Universit{\"a}t Potsdam},
year = {2011},
abstract = {Biology has made great progress in identifying and measuring the building blocks of life. The availability of high-throughput methods in molecular biology has dramatically accelerated the growth of biological knowledge for various organisms. The advancements in genomic, proteomic and metabolomic technologies allow for constructing complex models of biological systems. An increasing number of biological repositories is available on the web, incorporating thousands of biochemical reactions and genetic regulations. Systems Biology is a recent research trend in life science, which fosters a systemic view on biology. In Systems Biology one is interested in integrating the knowledge from all these different sources into models that capture the interaction of these entities. By studying these models one wants to understand the emerging properties of the whole system, such as robustness. However, both measurements as well as biological networks are prone to considerable incompleteness, heterogeneity and mutual inconsistency, which makes it highly non-trivial to draw biologically meaningful conclusions in an automated way. Therefore, we want to promote Answer Set Programming (ASP) as a tool for discrete modeling in Systems Biology. ASP is a declarative problem solving paradigm, in which a problem is encoded as a logic program such that its answer sets represent solutions to the problem. ASP has intrinsic features to cope with incompleteness, offers a rich modeling language and highly efficient solving technology. We present ASP solutions, for the analysis of genetic regulatory networks, determining consistency with observed measurements and identifying minimal causes for inconsistency. We extend this approach for computing minimal repairs on model and data that restore consistency. This method allows for predicting unobserved data even in case of inconsistency. Further, we present an ASP approach to metabolic network expansion. This approach exploits the easy characterization of reachability in ASP and its various reasoning methods, to explore the biosynthetic capabilities of metabolic reaction networks and generate hypotheses for extending the network. Finally, we present the BioASP library, a Python library which encapsulates our ASP solutions into the imperative programming paradigm. The library allows for an easy integration of ASP solution into system rich environments, as they exist in Systems Biology.},
language = {en}
}
@phdthesis{Dietze2004,
author = {Dietze, Stefan},
title = {Modell und Optimierungsansatz f{\"u}r Open Source Softwareentwicklungsprozesse},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-0001594},
school = {Universit{\"a}t Potsdam},
year = {2004},
abstract = {Gerade in den letzten Jahren erfuhr Open Source Software (OSS) eine zunehmende Verbreitung und Popularit{\"a}t und hat sich in verschiedenen Anwendungsdom{\"a}nen etabliert. Die Prozesse, welche sich im Kontext der OSS-Entwicklung (auch: OSSD \– Open Source Software-Development) evolution{\"a}r herausgebildet haben, weisen in den verschiedenen OSS-Entwicklungsprojekten z.T. {\"a}hnliche Eigenschaften und Strukturen auf und auch die involvierten Entit{\"a}ten, wie z.B. Artefakte, Rollen oder Software-Werkzeuge sind weitgehend miteinander vergleichbar. Dies motiviert den Gedanken, ein verallgemeinerbares Modell zu entwickeln, welches die generalisierbaren Entwicklungsprozesse im Kontext von OSS zu einem {\"u}bertragbaren Modell abstrahiert. Auch in der Wissenschaftsdisziplin des Software Engineering (SE) wurde bereits erkannt, dass sich der OSSD-Ansatz in verschiedenen Aspekten erheblich von klassischen (propriet{\"a}ren) Modellen des SE unterscheidet und daher diese Methoden einer eigenen wissenschaftlichen Betrachtung bed{\"u}rfen. In verschiedenen Publikationen wurden zwar bereits einzelne Aspekte der OSS-Entwicklung analysiert und Theorien {\"u}ber die zugrundeliegenden Entwicklungsmethoden formuliert, aber es existiert noch keine umfassende Beschreibung der typischen Prozesse der OSSD-Methodik, die auf einer empirischen Untersuchung existierender OSS-Entwicklungsprojekte basiert. Da dies eine Voraussetzung f{\"u}r die weitere wissenschaftliche Auseinandersetzung mit OSSD-Prozessen darstellt, wird im Rahmen dieser Arbeit auf der Basis vergleichender Fallstudien ein deskriptives Modell der OSSD-Prozesse hergeleitet und mit Modellierungselementen der UML formalisiert beschrieben. Das Modell generalisiert die identifizierten Prozesse, Prozessentit{\"a}ten und Software-Infrastrukturen der untersuchten OSSD-Projekte. Es basiert auf einem eigens entwickelten Metamodell, welches die zu analysierenden Entit{\"a}ten identifiziert und die Modellierungssichten und -elemente beschreibt, die zur UML-basierten Beschreibung der Entwicklungsprozesse verwendet werden. In einem weiteren Arbeitsschritt wird eine weiterf{\"u}hrende Analyse des identifizierten Modells durchgef{\"u}hrt, um Implikationen, und Optimierungspotentiale aufzuzeigen. Diese umfassen beispielsweise die ungen{\"u}gende Plan- und Terminierbarkeit von Prozessen oder die beobachtete Tendenz von OSSD-Akteuren, verschiedene Aktivit{\"a}ten mit unterschiedlicher Intensit{\"a}t entsprechend der subjektiv wahrgenommenen Anreize auszu{\"u}ben, was zur Vernachl{\"a}ssigung einiger Prozesse f{\"u}hrt. Anschließend werden Optimierungszielstellungen dargestellt, die diese Unzul{\"a}nglichkeiten adressieren, und ein Optimierungsansatz zur Verbesserung des OSSD-Modells wird beschrieben. Dieser Ansatz umfasst die Erweiterung der identifizierten Rollen, die Einf{\"u}hrung neuer oder die Erweiterung bereits identifizierter Prozesse und die Modifikation oder Erweiterung der Artefakte des generalisierten OSS-Entwicklungsmodells. Die vorgestellten Modellerweiterungen dienen vor allem einer gesteigerten Qualit{\"a}tssicherung und der Kompensation von vernachl{\"a}ssigten Prozessen, um sowohl die entwickelte Software- als auch die Prozessqualit{\"a}t im OSSD-Kontext zu verbessern. Desweiteren werden Softwarefunktionalit{\"a}ten beschrieben, welche die identifizierte bestehende Software-Infrastruktur erweitern und eine gesamtheitlichere, softwaretechnische Unterst{\"u}tzung der OSSD-Prozesse erm{\"o}glichen sollen. Abschließend werden verschiedene Anwendungsszenarien der Methoden des OSS-Entwicklungsmodells, u.a. auch im kommerziellen SE, identifiziert und ein Implementierungsansatz basierend auf der OSS GENESIS vorgestellt, der zur Implementierung und Unterst{\"u}tzung des OSSD-Modells verwendet werden kann.},
language = {de}
}
@phdthesis{RobinsonMallett2005,
author = {Robinson-Mallett, Christopher},
title = {Modellbasierte Modulpr{\"u}fung f{\"u}r die Entwicklung technischer, softwareintensiver Systeme mit Real-Time Object-Oriented Modeling},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-6045},
school = {Universit{\"a}t Potsdam},
year = {2005},
abstract = {Mit zunehmender Komplexit{\"a}t technischer Softwaresysteme ist die Nachfrage an produktiveren Methoden und Werkzeugen auch im sicherheitskritischen Umfeld gewachsen. Da insbesondere objektorientierte und modellbasierte Ans{\"a}tze und Methoden ausgezeichnete Eigenschaften zur Entwicklung großer und komplexer Systeme besitzen, ist zu erwarten, dass diese in naher Zukunft selbst bis in sicherheitskritische Bereiche der Softwareentwicklung vordringen. Mit der Unified Modeling Language Real-Time (UML-RT) wird eine Softwareentwicklungsmethode f{\"u}r technische Systeme durch die Object Management Group (OMG) propagiert. F{\"u}r den praktischen Einsatz im technischen und sicherheitskritischen Umfeld muss diese Methode nicht nur bestimmte technische Eigenschaften, beispielsweise temporale Analysierbarkeit, besitzen, sondern auch in einen bestehenden Qualit{\"a}tssicherungsprozess integrierbar sein. Ein wichtiger Aspekt der Integration der UML-RT in ein qualit{\"a}tsorientiertes Prozessmodell, beispielsweise in das V-Modell, ist die Verf{\"u}gbarkeit von ausgereiften Konzepten und Methoden f{\"u}r einen systematischen Modultest. Der Modultest dient als erste Qualitit{\"a}tssicherungsphase nach der Implementierung der Fehlerfindung und dem Qualit{\"a}tsnachweis f{\"u}r jede separat pr{\"u}fbare Softwarekomponente eines Systems. W{\"a}hrend dieser Phase stellt die Durchf{\"u}hrung von systematischen Tests die wichtigste Qualit{\"a}tssicherungsmaßnahme dar. W{\"a}hrend zum jetzigen Zeitpunkt zwar ausgereifte Methoden und Werkzeuge f{\"u}r die modellbasierte Softwareentwicklung zur Verf{\"u}gung stehen, existieren nur wenig {\"u}berzeugende L{\"o}sungen f{\"u}r eine systematische modellbasierte Modulpr{\"u}fung. Die durchg{\"a}ngige Verwendung ausf{\"u}hrbarer Modelle und Codegenerierung stellen wesentliche Konzepte der modellbasierten Softwareentwicklung dar. Sie dienen der konstruktiven Fehlerreduktion durch Automatisierung ansonsten fehlertr{\"a}chtiger, manueller Vorg{\"a}nge. Im Rahmen einer modellbasierten Qualit{\"a}tssicherung sollten diese Konzepte konsequenterweise in die sp{\"a}teren Qualit{\"a}tssicherungsphasen transportiert werden. Daher ist eine wesentliche Forderung an ein Verfahren zur modellbasierten Modulpr{\"u}fung ein m{\"o}glichst hoher Grad an Automatisierung. In aktuellen Entwicklungen hat sich f{\"u}r die Generierung von Testf{\"a}llen auf Basis von Zustandsautomaten die Verwendung von Model Checking als effiziente und an die vielf{\"a}ltigsten Testprobleme anpassbare Methode bew{\"a}hrt. Der Ansatz des Model Checking stammt urspr{\"u}nglich aus dem Entwurf von Kommunikationsprotokollen und wurde bereits erfolgreich auf verschiedene Probleme der Modellierung technischer Software angewendet. Insbesondere in der Gegenwart ausf{\"u}hrbarer, automatenbasierter Modelle erscheint die Verwendung von Model Checking sinnvoll, das die Existenz einer formalen, zustandsbasierten Spezifikation voraussetzt. Ein ausf{\"u}hrbares, zustandsbasiertes Modell erf{\"u}llt diese Anforderungen in der Regel. Aus diesen Gr{\"u}nden ist die Wahl eines Model Checking Ansatzes f{\"u}r die Generierung von Testf{\"a}llen im Rahmen eines modellbasierten Modultestverfahrens eine logische Konsequenz. Obwohl in der aktuellen Spezifikation der UML-RT keine eindeutigen Aussagen {\"u}ber den zur Verhaltensbeschreibung zu verwendenden Formalismus gemacht werden, ist es wahrscheinlich, dass es sich bei der UML-RT um eine zu Real-Time Object-Oriented Modeling (ROOM) kompatible Methode handelt. Alle in dieser Arbeit pr{\"a}sentierten Methoden und Ergebnisse sind somit auf die kommende UML-RT {\"u}bertragbar und von sehr aktueller Bedeutung. Aus den genannten Gr{\"u}nden verfolgt diese Arbeit das Ziel, die analytische Qualit{\"a}tssicherung in der modellbasierten Softwareentwicklung mittels einer modellbasierten Methode f{\"u}r den Modultest zu verbessern. Zu diesem Zweck wird eine neuartige Testmethode pr{\"a}sentiert, die auf automatenbasierten Verhaltensmodellen und CTL Model Checking basiert. Die Testfallgenerierung kann weitgehend automatisch erfolgen, um Fehler durch menschlichen Einfluss auszuschließen. Das entwickelte Modultestverfahren ist in die technischen Konzepte Model Driven Architecture und ROOM, beziehungsweise UML-RT, sowie in die organisatorischen Konzepte eines qualit{\"a}tsorientierten Prozessmodells, beispielsweise das V-Modell, integrierbar.},
subject = {Software},
language = {de}
}
@phdthesis{Hitz2021,
author = {Hitz, Michael},
title = {Modellierung und Generierung kombinierbarer Benutzungsschnittstellenvarianten und deren gemeinschaftliche Nutzung in Dienst-Ökosystemen},
doi = {10.25932/publishup-50022},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-500224},
school = {Universit{\"a}t Potsdam},
pages = {viii, 313},
year = {2021},
abstract = {Digitalisierung erm{\"o}glicht es uns, mit Partnern (z.B. Unternehmen, Institutionen) in einer IT-unterst{\"u}tzten Umgebung zu interagieren und T{\"a}tigkeiten auszuf{\"u}hren, die vormals manuell erledigt wurden. Ein Ziel der Digitalisierung ist dabei, Dienstleistungen unterschiedlicher fachlicher Dom{\"a}nen zu Prozessen zu kombinieren und vielen Nutzergruppen bedarfsgerecht zug{\"a}nglich zu machen. Hierzu stellen Anbieter technische Dienste bereit, die in unterschiedliche Anwendungen integriert werden k{\"o}nnen. Die Digitalisierung stellt die Anwendungsentwicklung vor neue Herausforderungen. Ein Aspekt ist die bedarfsgerechte Anbindung von Nutzern an Dienste. Zur Interaktion menschlicher Nutzer mit den Diensten werden Benutzungsschnittstellen ben{\"o}tigt, die auf deren Bed{\"u}rfnisse zugeschnitten sind. Hierzu werden Varianten f{\"u}r spezifische Nutzergruppen (fachliche Varianten) und variierende Umgebungen (technische Varianten) ben{\"o}tigt. Zunehmend m{\"u}ssen diese mit Diensten anderer Anbieter kombiniert werden k{\"o}nnen, um dom{\"a}nen{\"u}bergreifend Prozesse zu Anwendungen mit einem erh{\"o}hten Mehrwert f{\"u}r den Endnutzer zu verkn{\"u}pfen (z.B. eine Flugbuchung mit einer optionalen Reiseversicherung). Die Vielf{\"a}ltigkeit der Varianten l{\"a}sst die Erstellung von Benutzungsschnittstellen komplex und die Ergebnisse sehr individuell erscheinen. Daher werden die Varianten in der Praxis vorwiegend manuell erstellt. Dies f{\"u}hrt zur parallelen Entwicklung einer Vielzahl sehr {\"a}hnlicher Anwendungen, die nur geringes Potential zur Wiederverwendung besitzen. Die Folge sind hohe Aufw{\"a}nde bei Erstellung und Wartung. Dadurch wird h{\"a}ufig auf die Unterst{\"u}tzung kleiner Nutzerkreise mit speziellen Anforderungen verzichtet (z.B. Menschen mit physischen Einschr{\"a}nkungen), sodass diese weiterhin von der Digitalisierung ausgeschlossen bleiben. Die Arbeit stellt eine konsistente L{\"o}sung f{\"u}r diese neuen Herausforderungen mit den Mitteln der modellgetriebenen Entwicklung vor. Sie präsentiert einen Ansatz zur Modellierung von Benutzungsschnittstellen, Varianten und Kompositionen und deren automatischer Generierung f{\"u}r digitale Dienste in einem verteilten Umfeld. Die Arbeit schafft eine L{\"o}sung zur Wiederverwendung und gemeinschaftlichen Nutzung von Benutzungsschnittstellen {\"u}ber Anbietergrenzen hinweg. Sie f{\"u}hrt zu einer Infrastruktur, in der eine Vielzahl von Anbietern ihre Expertise in gemeinschaftliche Anwendungen einbringen k{\"o}nnen. Die Beitr{\"a}ge bestehen im Einzelnen in Konzepten und Metamodellen zur Modellierung von Benutzungsschnittstellen, Varianten und Kompositionen sowie einem Verfahren zu deren vollst{\"a}ndig automatisierten Transformation in funktionale Benutzungsschnittstellen. Zur Umsetzung der gemeinschaftlichen Nutzbarkeit werden diese erg{\"a}nzt um eine universelle Repr{\"a}sentation der Modelle, einer Methodik zur Anbindung unterschiedlicher Dienst-Anbieter sowie einer Architektur zur verteilten Nutzung der Artefakte und Verfahren in einer dienstorientierten Umgebung. Der Ansatz bietet die Chance, unterschiedlichste Menschen bedarfsgerecht an der Digitalisierung teilhaben zu lassen. Damit setzt die Arbeit Impulse f{\"u}r zuk{\"u}nftige Methoden zur Anwendungserstellung in einem zunehmend vielf{\"a}ltigen Umfeld.},
language = {de}
}
@phdthesis{Hoellerer2016,
author = {H{\"o}llerer, Reinhard},
title = {Modellierung und Optimierung von B{\"u}rgerdiensten am Beispiel der Stadt Landshut},
doi = {10.25932/publishup-42598},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-425986},
school = {Universit{\"a}t Potsdam},
pages = {xii, 244},
year = {2016},
abstract = {Die Projektierung und Abwicklung sowie die statische und dynamische Analyse von Gesch{\"a}ftsprozessen im Bereich des Verwaltens und Regierens auf kommunaler, L{\"a}nder- wie auch Bundesebene mit Hilfe von Informations- und Kommunikationstechniken besch{\"a}ftigen Politiker und Strategen f{\"u}r Informationstechnologie ebenso wie die {\"O}ffentlichkeit seit Langem. Der hieraus entstandene Begriff E-Government wurde in der Folge aus den unterschiedlichsten technischen, politischen und semantischen Blickrichtungen beleuchtet. Die vorliegende Arbeit konzentriert sich dabei auf zwei Schwerpunktthemen: • Das erste Schwerpunktthema behandelt den Entwurf eines hierarchischen Architekturmodells, f{\"u}r welches sieben hierarchische Schichten identifiziert werden k{\"o}nnen. Diese erscheinen notwendig, aber auch hinreichend, um den allgemeinen Fall zu beschreiben. Den Hintergrund hierf{\"u}r liefert die langj{\"a}hrige Prozess- und Verwaltungserfahrung als Leiter der EDV-Abteilung der Stadtverwaltung Landshut, eine kreisfreie Stadt mit rund 69.000 Einwohnern im Nordosten von M{\"u}nchen. Sie steht als Repr{\"a}sentant f{\"u}r viele Verwaltungsvorg{\"a}nge in der Bundesrepublik Deutschland und ist dennoch als Analyseobjekt in der Gesamtkomplexit{\"a}t und Prozessquantit{\"a}t {\"u}berschaubar. Somit k{\"o}nnen aus der Analyse s{\"a}mtlicher Kernabl{\"a}ufe statische und dynamische Strukturen extrahiert und abstrakt modelliert werden. Die Schwerpunkte liegen in der Darstellung der vorhandenen Bedienabl{\"a}ufe in einer Kommune. Die Transformation der Bedienanforderung in einem hierarchischen System, die Darstellung der Kontroll- und der Operationszust{\"a}nde in allen Schichten wie auch die Strategie der Fehlererkennung und Fehlerbehebung schaffen eine transparente Basis f{\"u}r umfassende Restrukturierungen und Optimierungen. F{\"u}r die Modellierung wurde FMC-eCS eingesetzt, eine am Hasso-Plattner-Institut f{\"u}r Softwaresystemtechnik GmbH (HPI) im Fachgebiet Kommunikationssysteme entwickelte Methodik zur Modellierung zustandsdiskreter Systeme unter Ber{\"u}cksichtigung m{\"o}glicher Inkonsistenzen (Betreuer: Prof. Dr.-Ing. Werner Zorn [ZW07a, ZW07b]). • Das zweite Schwerpunktthema widmet sich der quantitativen Modellierung und Optimierung von E-Government-Bediensystemen, welche am Beispiel des B{\"u}rgerb{\"u}ros der Stadt Landshut im Zeitraum 2008 bis 2015 durchgef{\"u}hrt wurden. Dies erfolgt auf Basis einer kontinuierlichen Betriebsdatenerfassung mit aufwendiger Vorverarbeitung zur Extrahierung mathematisch beschreibbarer Wahrscheinlichkeitsverteilungen. Der hieraus entwickelte Dienstplan wurde hinsichtlich der erzielbaren Optimierungen im dauerhaften Echteinsatz verifiziert. [ZW07a] Zorn, Werner: «FMC-QE A New Approach in Quantitative Modeling», Vortrag anl{\"a}sslich: MSV'07- The 2007 International Conference on Modeling, Simulation and Visualization Methods WorldComp2007, Las Vegas, 28.6.2007. [ZW07b] Zorn, Werner: «FMC-QE, A New Approach in Quantitative Modeling», Ver{\"o}ffentlichung, Hasso-Plattner-Institut f{\"u}r Softwaresystemtechnik an der Universit{\"a}t Potsdam, 28.6.2007.},
language = {de}
}
@article{MagenheimSchubertSchapert2015,
author = {Magenheim, Johannes and Schubert, Sigrid and Schapert, Niclas},
title = {Modelling and Measurement of Competencies in Computer Science Education},
series = {KEYCIT 2014 - Key Competencies in Informatics and ICT},
journal = {KEYCIT 2014 - Key Competencies in Informatics and ICT},
number = {7},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-82592},
pages = {33 -- 57},
year = {2015},
abstract = {As a result of the Bologna reform of educational systems in Europe the outcome orientation of learning processes, competence-oriented descriptions of the curricula and competence-oriented assessment procedures became standard also in Computer Science Education (CSE). The following keynote addresses important issues of shaping a CSE competence model especially in the area of informatics system comprehension and object-oriented modelling. Objectives and research methodology of the project MoKoM (Modelling and Measurement of Competences in CSE) are explained. Firstly, the CSE competence model was derived based on theoretical concepts and then secondly the model was empirically examined and refined using expert interviews. Furthermore, the paper depicts the development and examination of a competence measurement instrument, which was derived from the competence model. Therefore, the instrument was applied to a large sample of students at the gymnasium's upper class level. Subsequently, efforts to develop a competence level model, based on the retrieved empirical results and on expert ratings are presented. Finally, further demands on research on competence modelling in CSE will be outlined.},
language = {en}
}
@phdthesis{Ostrowski2018,
author = {Ostrowski, Max},
title = {Modern constraint answer set solving},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-407799},
school = {Universit{\"a}t Potsdam},
pages = {135},
year = {2018},
abstract = {Answer Set Programming (ASP) is a declarative problem solving approach, combining a rich yet simple modeling language with high-performance solving capabilities. Although this has already resulted in various applications, certain aspects of such applications are more naturally modeled using variables over finite domains, for accounting for resources, fine timings, coordinates, or functions. Our goal is thus to extend ASP with constraints over integers while preserving its declarative nature. This allows for fast prototyping and elaboration tolerant problem descriptions of resource related applications. The resulting paradigm is called Constraint Answer Set Programming (CASP). We present three different approaches for solving CASP problems. The first one, a lazy, modular approach combines an ASP solver with an external system for handling constraints. This approach has the advantage that two state of the art technologies work hand in hand to solve the problem, each concentrating on its part of the problem. The drawback is that inter-constraint dependencies cannot be communicated back to the ASP solver, impeding its learning algorithm. The second approach translates all constraints to ASP. Using the appropriate encoding techniques, this results in a very fast, monolithic system. Unfortunately, due to the large, explicit representation of constraints and variables, translation techniques are restricted to small and mid-sized domains. The third approach merges the lazy and the translational approach, combining the strength of both while removing their weaknesses. To this end, we enhance the dedicated learning techniques of an ASP solver with the inferences of the translating approach in a lazy way. That is, the important knowledge is only made explicit when needed. By using state of the art techniques from neighboring fields, we provide ways to tackle real world, industrial size problems. By extending CASP to reactive solving, we open up new application areas such as online planning with continuous domains and durations.},
language = {en}
}
@article{ReinhardtMagenheim2009,
author = {Reinhardt, Wolfgang and Magenheim, Johannes},
title = {Modulares Konzept f{\"u}r die Tutorenschulung in der universit{\"a}ren Informatikausbildung},
series = {Commentarii informaticae didacticae : (CID)},
journal = {Commentarii informaticae didacticae : (CID)},
number = {1},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-29684},
pages = {105 -- 118},
year = {2009},
abstract = {Die nachhaltige Integration von Blended Learning in den Informatik-Lehrbetrieb von Pr{\"a}senzhochschulen und die Qualit{\"a}tssicherung der Lehre mit digitalen Medien beruht nicht nur auf der Verf{\"u}gbarkeit von Lernmaterialien und dem Zugang zu Lernplattformen, sondern erfordert auch Qualifizierungsmaßnahmen f{\"u}r die Lehrenden. Am Beispiel der Gestaltung von vorlesungsbegleitenden {\"U}bungen in der universit{\"a}ren Informatikausbildung wird ein Konzept f{\"u}r die Schulung von Tutoren vorgestellt, das sich an den Erfordernissen des {\"U}bungsbetriebs und den unterschiedlichen Arbeits- und Lernkontexten der k{\"u}nftigen Tutoren orientiert. Das Konzept basiert auf mehrj{\"a}hrigen Praxiserfahrungen mit Schulungsworkshops f{\"u}r Tutoren in der Informatik, die nun aufgrund aktueller didaktischer Konzepte zum Blended Learning und unter Ber{\"u}cksichtigung von Umfrageergebnissen unter studentischen Tutoren modifiziert wurden. Das neu entwickelte modulare Konzept zur Tutorenschulung befindet sich aktuell in einer erweiterten Pilotphase.},
language = {de}
}
@phdthesis{Glander2012,
author = {Glander, Tassilo},
title = {Multi-scale representations of virtual 3D city models},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-64117},
school = {Universit{\"a}t Potsdam},
year = {2012},
abstract = {Virtual 3D city and landscape models are the main subject investigated in this thesis. They digitally represent urban space and have many applications in different domains, e.g., simulation, cadastral management, and city planning. Visualization is an elementary component of these applications. Photo-realistic visualization with an increasingly high degree of detail leads to fundamental problems for comprehensible visualization. A large number of highly detailed and textured objects within a virtual 3D city model may create visual noise and overload the users with information. Objects are subject to perspective foreshortening and may be occluded or not displayed in a meaningful way, as they are too small. In this thesis we present abstraction techniques that automatically process virtual 3D city and landscape models to derive abstracted representations. These have a reduced degree of detail, while essential characteristics are preserved. After introducing definitions for model, scale, and multi-scale representations, we discuss the fundamentals of map generalization as well as techniques for 3D generalization. The first presented technique is a cell-based generalization of virtual 3D city models. It creates abstract representations that have a highly reduced level of detail while maintaining essential structures, e.g., the infrastructure network, landmark buildings, and free spaces. The technique automatically partitions the input virtual 3D city model into cells based on the infrastructure network. The single building models contained in each cell are aggregated to abstracted cell blocks. Using weighted infrastructure elements, cell blocks can be computed on different hierarchical levels, storing the hierarchy relation between the cell blocks. Furthermore, we identify initial landmark buildings within a cell by comparing the properties of individual buildings with the aggregated properties of the cell. For each block, the identified landmark building models are subtracted using Boolean operations and integrated in a photo-realistic way. Finally, for the interactive 3D visualization we discuss the creation of the virtual 3D geometry and their appearance styling through colors, labeling, and transparency. We demonstrate the technique with example data sets. Additionally, we discuss applications of generalization lenses and transitions between abstract representations. The second technique is a real-time-rendering technique for geometric enhancement of landmark objects within a virtual 3D city model. Depending on the virtual camera distance, landmark objects are scaled to ensure their visibility within a specific distance interval while deforming their environment. First, in a preprocessing step a landmark hierarchy is computed, this is then used to derive distance intervals for the interactive rendering. At runtime, using the virtual camera distance, a scaling factor is computed and applied to each landmark. The scaling factor is interpolated smoothly at the interval boundaries using cubic B{\´e}zier splines. Non-landmark geometry that is near landmark objects is deformed with respect to a limited number of landmarks. We demonstrate the technique by applying it to a highly detailed virtual 3D city model and a generalized 3D city model. In addition we discuss an adaptation of the technique for non-linear projections and mobile devices. The third technique is a real-time rendering technique to create abstract 3D isocontour visualization of virtual 3D terrain models. The virtual 3D terrain model is visualized as a layered or stepped relief. The technique works without preprocessing and, as it is implemented using programmable graphics hardware, can be integrated with minimal changes into common terrain rendering techniques. Consequently, the computation is done in the rendering pipeline for each vertex, primitive, i.e., triangle, and fragment. For each vertex, the height is quantized to the nearest isovalue. For each triangle, the vertex configuration with respect to their isovalues is determined first. Using the configuration, the triangle is then subdivided. The subdivision forms a partial step geometry aligned with the triangle. For each fragment, the surface appearance is determined, e.g., depending on the surface texture, shading, and height-color-mapping. Flexible usage of the technique is demonstrated with applications from focus+context visualization, out-of-core terrain rendering, and information visualization. This thesis presents components for the creation of abstract representations of virtual 3D city and landscape models. Re-using visual language from cartography, the techniques enable users to build on their experience with maps when interpreting these representations. Simultaneously, characteristics of 3D geovirtual environments are taken into account by addressing and discussing, e.g., continuous scale, interaction, and perspective.},
language = {en}
}
@phdthesis{Jiang2007,
author = {Jiang, Chunyan},
title = {Multi-visualization and hybrid segmentation approaches within telemedicine framework},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-12829},
school = {Universit{\"a}t Potsdam},
year = {2007},
abstract = {The innovation of information techniques has changed many aspects of our life. In health care field, we can obtain, manage and communicate high-quality large volumetric image data by computer integrated devices, to support medical care. In this dissertation I propose several promising methods that could assist physicians in processing, observing and communicating the image data. They are included in my three research aspects: telemedicine integration, medical image visualization and image segmentation. And these methods are also demonstrated by the demo software that I developed. One of my research point focuses on medical information storage standard in telemedicine, for example DICOM, which is the predominant standard for the storage and communication of medical images. I propose a novel 3D image data storage method, which was lacking in current DICOM standard. I also created a mechanism to make use of the non-standard or private DICOM files. In this thesis I present several rendering techniques on medical image visualization to offer different display manners, both 2D and 3D, for example, cut through data volume in arbitrary degree, rendering the surface shell of the data, and rendering the semi-transparent volume of the data. A hybrid segmentation approach, designed for semi-automated segmentation of radiological image, such as CT, MRI, etc, is proposed in this thesis to get the organ or interested area from the image. This approach takes advantage of the region-based method and boundary-based methods. Three steps compose the hybrid approach: the first step gets coarse segmentation by fuzzy affinity and generates homogeneity operator; the second step divides the image by Voronoi Diagram and reclassifies the regions by the operator to refine segmentation from the previous step; the third step handles vague boundary by level set model. Topics for future research are mentioned in the end, including new supplement for DICOM standard for segmentation information storage, visualization of multimodal image information, and improvement of the segmentation approach to higher dimension.},
language = {en}
}
@misc{SahlmannClemensNowaketal.2020,
author = {Sahlmann, Kristina and Clemens, Vera and Nowak, Michael and Schnor, Bettina},
title = {MUP},
series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
number = {1094},
issn = {1866-8372},
doi = {10.25932/publishup-48901},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-489013},
pages = {23},
year = {2020},
abstract = {Message Queuing Telemetry Transport (MQTT) is one of the dominating protocols for edge- and cloud-based Internet of Things (IoT) solutions. When a security vulnerability of an IoT device is known, it has to be fixed as soon as possible. This requires a firmware update procedure. In this paper, we propose a secure update protocol for MQTT-connected devices which ensures the freshness of the firmware, authenticates the new firmware and considers constrained devices. We show that the update protocol is easy to integrate in an MQTT-based IoT network using a semantic approach. The feasibility of our approach is demonstrated by a detailed performance analysis of our prototype implementation on a IoT device with 32 kB RAM. Thereby, we identify design issues in MQTT 5 which can help to improve the support of constrained devices.},
language = {en}
}
@article{ReynoldsSwainstonBendrups2015,
author = {Reynolds, Nicholas and Swainston, Andrew and Bendrups, Faye},
title = {Music Technology and Computational Thinking},
series = {KEYCIT 2014 - Key Competencies in Informatics and ICT},
journal = {KEYCIT 2014 - Key Competencies in Informatics and ICT},
number = {7},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-82913},
pages = {363 -- 370},
year = {2015},
abstract = {A project involving the composition of a number of pieces of music by public participants revealed levels of engagement with and mastery of complex music technologies by a number of secondary student volunteers. This paper reports briefly on some initial findings of that project and seeks to illuminate an understanding of computational thinking across the curriculum.},
language = {en}
}
@phdthesis{Dehne2021,
author = {Dehne, Julian},
title = {M{\"o}glichkeiten und Limitationen der medialen Unterst{\"u}tzung forschenden Lernens},
doi = {10.25932/publishup-49789},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-497894},
school = {Universit{\"a}t Potsdam},
pages = {xvii, 404},
year = {2021},
abstract = {Forschendes Lernen und die digitale Transformation sind zwei der wichtigsten Einfl{\"u}sse auf die Entwicklung der Hochschuldidaktik im deutschprachigen Raum. W{\"a}hrend das forschende Lernen als normative Theorie das sollen beschreibt, geben die digitalen Werkzeuge, alte wie neue, das k{\"o}nnen in vielen Bereichen vor. In der vorliegenden Arbeit wird ein Prozessmodell aufgestellt, was den Versuch unternimmt, das forschende Lernen hinsichtlich interaktiver, gruppenbasierter Prozesse zu systematisieren. Basierend auf dem entwickelten Modell wurde ein Softwareprototyp implementiert, der den gesamten Forschungsprozess begleiten kann. Dabei werden Gruppenformation, Feedback- und Reflexionsprozesse und das Peer Assessment mit Bildungstechnologien unterst{\"u}tzt. Die Entwicklungen wurden in einem qualitativen Experiment eingesetzt, um Systemwissen {\"u}ber die M{\"o}glichkeiten und Grenzen der digitalen Unterst{\"u}tzung von forschendem Lernen zu gewinnen.},
language = {de}
}
@article{EirundSethmann2009,
author = {Eirund, Helmut and Sethmann, Richard},
title = {NetS-X : Netzsicherheit lernen mit Spaß},
series = {Commentarii informaticae didacticae : (CID)},
journal = {Commentarii informaticae didacticae : (CID)},
number = {1},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-29660},
pages = {81 -- 92},
year = {2009},
abstract = {Das Gebiet der Netzsicherheit ist ein schwer zu lehrendes und m{\"u}hsam zu lernendes Fach in der Informatikausbildung. Dies hat verschiedene Gr{\"u}nde, z.B. erfordert es Fachkenntnis, die jenseits von bunten Bildern zu vermitteln ist und sich dabei mit geringer Halbwertszeit weiterentwickelt. Echte Bedrohungsszenarien m{\"u}ssen unter Laborbedingungen nachgestellt werden, und der Umgang mit den Sicherheitswerkzeugen ist sehr komplex. Auf der einen Seite muss das System konzeptionell verstanden werden und auf der anderen Seite sind viele Details in der Konfiguration von Firewalls, Netz-Komponenten und -Werkzeugen f{\"u}r klassische Pr{\"u}fungssituationen in der Ausbildung anzuwenden. Mit NetS-X (Network Security Experience) stellen wir einen laufenden Prototyp einer e-learning Plattform vor, mit der ein weiter Bereich von Sicherheitsszenarien vermittelt werden kann. Dabei wird der Lernende in einem Spielsystem mit Situationen konfrontiert, die er in einer echten, auf Linux basierenden typischen IT-Infrastruktur eines Unternehmens beherrschen muss. Die sicherheitsrelevanten Aktivit{\"a}ten des Lernenden, z.B. der Einsatz von Monitor-Werkzeugen oder die Konfiguration von Netz-Komponenten werden dabei nicht simuliert, sondern real durchgef{\"u}hrt und durch Prozesse des Spielsystems beobachtet und bewertet. Autorenwerkzeuge erm{\"o}glichen den Lehrenden und Spielern, selber neue Spielsituationen, Sicherheitsszenarien oder Wissenskomponenten in das System zu integrieren.},
language = {de}
}
@phdthesis{Sahlmann2021,
author = {Sahlmann, Kristina},
title = {Network management with semantic descriptions for interoperability on the Internet of Things},
doi = {10.25932/publishup-52984},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-529846},
school = {Universit{\"a}t Potsdam},
pages = {x, 272},
year = {2021},
abstract = {The Internet of Things (IoT) is a system of physical objects that can be discovered, monitored, controlled, or interacted with by electronic devices that communicate over various networking interfaces and eventually can be connected to the wider Internet. [Guinard and Trifa, 2016]. IoT devices are equipped with sensors and/or actuators and may be constrained in terms of memory, computational power, network bandwidth, and energy. Interoperability can help to manage such heterogeneous devices. Interoperability is the ability of different types of systems to work together smoothly. There are four levels of interoperability: physical, network and transport, integration, and data. The data interoperability is subdivided into syntactic and semantic data. Semantic data describes the meaning of data and the common understanding of vocabulary e.g. with the help of dictionaries, taxonomies, ontologies. To achieve interoperability, semantic interoperability is necessary. Many organizations and companies are working on standards and solutions for interoperability in the IoT. However, the commercial solutions produce a vendor lock-in. They focus on centralized approaches such as cloud-based solutions. This thesis proposes a decentralized approach namely Edge Computing. Edge Computing is based on the concepts of mesh networking and distributed processing. This approach has an advantage that information collection and processing are placed closer to the sources of this information. The goals are to reduce traffic, latency, and to be robust against a lossy or failed Internet connection. We see management of IoT devices from the network configuration management perspective. This thesis proposes a framework for network configuration management of heterogeneous, constrained IoT devices by using semantic descriptions for interoperability. The MYNO framework is an acronym for MQTT, YANG, NETCONF and Ontology. The NETCONF protocol is the IETF standard for network configuration management. The MQTT protocol is the de-facto standard in the IoT. We picked up the idea of the NETCONF-MQTT bridge, originally proposed by Scheffler and Bonneß[2017], and extended it with semantic device descriptions. These device descriptions provide a description of the device capabilities. They are based on the oneM2M Base ontology and formalized by the Semantic Web Standards. The novel approach is using a ontology-based device description directly on a constrained device in combination with the MQTT protocol. The bridge was extended in order to query such descriptions. Using a semantic annotation, we achieved that the device capabilities are self-descriptive, machine readable and re-usable. The concept of a Virtual Device was introduced and implemented, based on semantic device descriptions. A Virtual Device aggregates the capabilities of all devices at the edge network and contributes therefore to the scalability. Thus, it is possible to control all devices via a single RPC call. The model-driven NETCONF Web-Client is generated automatically from this YANG model which is generated by the bridge based on the semantic device description. The Web-Client provides a user-friendly interface, offers RPC calls and displays sensor values. We demonstrate the feasibility of this approach in different use cases: sensor and actuator scenarios, as well as event configuration and triggering. The semantic approach results in increased memory overhead. Therefore, we evaluated CBOR and RDF HDT for optimization of ontology-based device descriptions for use on constrained devices. The evaluation shows that CBOR is not suitable for long strings and RDF HDT is a promising candidate but is still a W3C Member Submission. Finally, we used an optimized JSON-LD format for the syntax of the device descriptions. One of the security tasks of network management is the distribution of firmware updates. The MYNO Update Protocol (MUP) was developed and evaluated on constrained devices CC2538dk and 6LoWPAN. The MYNO update process is focused on freshness and authenticity of the firmware. The evaluation shows that it is challenging but feasible to bring the firmware updates to constrained devices using MQTT. As a new requirement for the next MQTT version, we propose to add a slicing feature for the better support of constrained devices. The MQTT broker should slice data to the maximum packet size specified by the device and transfer it slice-by-slice. For the performance and scalability evaluation of MYNO framework, we setup the High Precision Agriculture demonstrator with 10 ESP-32 NodeMCU boards at the edge of the network. The ESP-32 NodeMCU boards, connected by WLAN, were equipped with six sensors and two actuators. The performance evaluation shows that the processing of ontology-based descriptions on a Raspberry Pi 3B with the RDFLib is a challenging task regarding computational power. Nevertheless, it is feasible because it must be done only once per device during the discovery process. The MYNO framework was tested with heterogeneous devices such as CC2538dk from Texas Instruments, Arduino Y{\´u}n Rev 3, and ESP-32 NodeMCU, and IP-based networks such as 6LoWPAN and WLAN. Summarizing, with the MYNO framework we could show that the semantic approach on constrained devices is feasible in the IoT.},
language = {en}
}
@phdthesis{Lanfermann2002,
author = {Lanfermann, Gerd},
title = {Nomadic migration : a service environment for autonomic computing on the Grid},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-0000773},
school = {Universit{\"a}t Potsdam},
year = {2002},
abstract = {In den vergangenen Jahren ist es zu einer dramatischen Vervielfachung der verf{\"u}gbaren Rechenzeit gekommen. Diese 'Grid Ressourcen' stehen jedoch nicht als kontinuierlicher Strom zur Verf{\"u}gung, sondern sind {\"u}ber verschiedene Maschinentypen, Plattformen und Betriebssysteme verteilt, die jeweils durch Netzwerke mit fluktuierender Bandbreite verbunden sind. Es wird f{\"u}r Wissenschaftler zunehmend schwieriger, die verf{\"u}gbaren Ressourcen f{\"u}r ihre Anwendungen zu nutzen. Wir glauben, dass intelligente, selbstbestimmende Applikationen in der Lage sein sollten, ihre Ressourcen in einer dynamischen und heterogenen Umgebung selbst zu w{\"a}hlen: Migrierende Applikationen suchen eine neue Ressource, wenn die alte aufgebraucht ist. 'Spawning'-Anwendungen lassen Algorithmen auf externen Maschinen laufen, um die Hauptanwendung zu beschleunigen. Applikationen werden neu gestartet, sobald ein Absturz endeckt wird. Alle diese Verfahren k{\"o}nnen ohne menschliche Interaktion erfolgen. Eine verteilte Rechenumgebung besitzt eine nat{\"u}rliche Unverl{\"a}sslichkeit. Jede Applikation, die mit einer solchen Umgebung interagiert, muss auf die gest{\"o}rten Komponenten reagieren k{\"o}nnen: schlechte Netzwerkverbindung, abst{\"u}rzende Maschinen, fehlerhafte Software. Wir konstruieren eine verl{\"a}ssliche Serviceinfrastruktur, indem wir der Serviceumgebung eine 'Peer-to-Peer'-Topology aufpr{\"a}gen. Diese "Grid Peer Service" Infrastruktur beinhaltet Services wie Migration und Spawning, als auch Services zum Starten von Applikationen, zur Datei{\"u}bertragung und Auswahl von Rechenressourcen. Sie benutzt existierende Gridtechnologie wo immer m{\"o}glich, um ihre Aufgabe durchzuf{\"u}hren. Ein Applikations-Information- Server arbeitet als generische Registratur f{\"u}r alle Teilnehmer in der Serviceumgebung. Die Serviceumgebung, die wir entwickelt haben, erlaubt es Applikationen z.B. eine Relokationsanfrage an einen Migrationsserver zu stellen. Der Server sucht einen neuen Computer, basierend auf den {\"u}bermittelten Ressourcen-Anforderungen. Er transferiert den Statusfile des Applikation zu der neuen Maschine und startet die Applikation neu. Obwohl das umgebende Ressourcensubstrat nicht kontinuierlich ist, k{\"o}nnen wir kontinuierliche Berechnungen auf Grids ausf{\"u}hren, indem wir die Applikation migrieren. Wir zeigen mit realistischen Beispielen, wie sich z.B. ein traditionelles Genom-Analyse-Programm leicht modifizieren l{\"a}sst, um selbstbestimmte Migrationen in dieser Serviceumgebung durchzuf{\"u}hren.},
subject = {Peer-to-Peer-Netz ; GRID computing ; Zuverl{\"a}ssigkeit ; Web Services ; Betriebsmittelverwaltung ; Migration},
language = {en}
}
@article{Opel2015,
author = {Opel, Simone},
title = {On the Way to a "General Model of Contextualised Computer Science Education"},
series = {KEYCIT 2014 - Key Competencies in Informatics and ICT},
journal = {KEYCIT 2014 - Key Competencies in Informatics and ICT},
number = {7},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-82953},
pages = {397 -- 400},
year = {2015},
language = {en}
}
@phdthesis{Christgau2017,
author = {Christgau, Steffen},
title = {One-sided communication on a non-cache-coherent many-core architecture},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-403100},
school = {Universit{\"a}t Potsdam},
pages = {219},
year = {2017},
abstract = {Aktuelle Mehrkernprozessoren stellen parallele Systeme dar, die den darauf ausgef{\"u}hrten Programmen gemeinsamen Speicher zur Verf{\"u}gung stellen. Sowohl die ansteigende Kernanzahlen in sogenannten Vielkernprozessoren (many-core processors) als auch die weiterhin steigende Leistungsf{\"a}higkeit der einzelnen Kerne erfordert hohe Bandbreiten, die das Speichersystem des Prozessors liefern muss. Hardware-basierte Cache-Koh{\"a}renz st{\"o}ßt in aktuellen Vielkernprozessoren an Grenzen des praktisch Machbaren. Dementsprechend m{\"u}ssen alternative Architekturen und entsprechend geeignete Programmiermodelle untersucht werden. In dieser Arbeit wird der Single-Chip Cloud Computer (SCC), ein nicht-cachekoh{\"a}renter Vielkernprozessor betrachtet, der aus 48, {\"u}ber ein Gitternetzwerk verbundenen Kernen besteht. Obwohl der Prozessor f{\"u}r nachrichten-basierte Kommunikation entwickelt worden ist, zeigen die Ergebnisse dieser Arbeit, dass einseitige Kommunikation auf Basis gemeinsamen Speichers effizient auf diesem Architekturtyp realisiert werden kann. Einseitige Kommunikation erm{\"o}glicht Datenaustausch zwischen Prozessen, bei der der Empf{\"a}nger keine Details {\"u}ber die stattfindende Kommunikation besitzen muss. Im Sinne des MPI-Standards ist so ein Zugriff auf Speicher entfernter Prozesse m{\"o}glich. Zur Umsetzung dieses Konzepts auf nicht-koh{\"a}renten Architekturen werden in dieser Arbeit sowohl eine effiziente Prozesssynchronisation als auch ein Kommunikationsschema auf Basis von software-basierter Cache-Koh{\"a}renz erarbeitet und untersucht. Die Prozesssynchronisation setzt das Konzept der general active target synchronization aus dem MPI-Standard um. Ein existierendes Klassifikationsschema f{\"u}r dessen Implementierungen wird erweitert und zur Identifikation einer geeigneten Klasse f{\"u}r die nicht-koh{\"a}rente Plattform des SCC verwendet. Auf Grundlage der Klassifikation werden existierende Implementierungen analysiert, daraus geeignete Konzepte extrahiert und ein leichtgewichtiges Synchronisationsprotokoll f{\"u}r den SCC entwickelt, das sowohl gemeinsamen Speicher als auch ungecachete Speicherzugriffe verwendet. Das vorgestellte Schema ist nicht anf{\"a}llig f{\"u}r Verz{\"o}gerungen zwischen Prozessen und erlaubt direkte Kommunikation sobald beide Kommunikationspartner daf{\"u}r bereit sind. Die experimentellen Ergebnisse zeigen ein sehr gutes Skaliserungsverhalten und eine f{\"u}nffach geringere Latenz f{\"u}r die Prozesssynchronisation im Vergleich zu einer auf Nachrichten basierenden MPI-Implementierung des SCC. F{\"u}r die Kommunikation wird mit SCOSCo ein auf gemeinsamen Speicher und software-basierter Cache-Koh{\"a}renz basierenden Konzept vorgestellt. Entsprechende Anforderungen an die Koh{\"a}renz, die dem MPI-Standard entsprechen, werden aufgestellt und eine schlanke Implementierung auf Basis der Hard- und Software-Funktionalit{\"a}ten des SCCs entwickelt. Trotz einer aufgedecktem Fehlfunktion im Speichersubsystem des SCC kann in den experimentellen Auswertungen von Mikrobenchmarks eine f{\"u}nffach verbesserte Bandbreite und eine nahezu vierfach verringerte Latenz beobachtet werden. In Anwendungsexperimenten, wie einer dreidimensionalen schnellen Fourier-Transformation, kann der Anteil der Kommunikation an der Laufzeit um den Faktor f{\"u}nf reduziert werden. In Erg{\"a}nzung dazu werden in dieser Arbeit Konzepte aufgestellt, die in zuk{\"u}nftigen Architekturen, die Cache-Koh{\"a}renz nicht auf einer globalen Ebene des Prozessors liefern k{\"o}nnen, f{\"u}r die Umsetzung von Software-basierter Koh{\"a}renz f{\"u}r einseitige Kommunikation hilfreich sind.},
language = {en}
}
@phdthesis{Morozov2005,
author = {Morozov, Alexei},
title = {Optimierung von Fehlererkennungsschaltungen auf der Grundlage von komplement{\"a}ren Erg{\"a}nzungen f{\"u}r 1-aus-3 und Berger Codes},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-5360},
school = {Universit{\"a}t Potsdam},
year = {2005},
abstract = {Die Dissertation stellt eine neue Herangehensweise an die L{\"o}sung der Aufgabe der funktionalen Diagnostik digitaler Systeme vor. In dieser Arbeit wird eine neue Methode f{\"u}r die Fehlererkennung vorgeschlagen, basierend auf der Logischen Erg{\"a}nzung und der Verwendung von Berger-Codes und dem 1-aus-3 Code. Die neue Fehlererkennungsmethode der Logischen Erg{\"a}nzung gestattet einen hohen Optimierungsgrad der ben{\"o}tigten Realisationsfl{\"a}che der konstruierten Fehlererkennungsschaltungen. Außerdem ist eins der wichtigen in dieser Dissertation gel{\"o}sten Probleme die Synthese vollst{\"a}ndig selbstpr{\"u}fender Schaltungen.},
subject = {logische Erg{\"a}nzung},
language = {de}
}
@article{HeinischRomeike2013,
author = {Heinisch, Isabelle and Romeike, Ralf},
title = {Outcome-orientierte Neuausrichtung in der Hochschullehre Informatik},
series = {Commentarii informaticae didacticae : (CID)},
journal = {Commentarii informaticae didacticae : (CID)},
number = {5},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-64831},
pages = {9 -- 20},
year = {2013},
abstract = {Die Orientierung am Outcome eines Lernprozesses stellt einen wichtigen Pfeiler einer kompetenzorientierten Informatiklehre dar. Im Beitrag werden Konzeption und Erfahrungen eines Projekts zur outcome-orientierten Neuausrichtung der Informatiklehre unter Ber{\"u}cksichtigung der Theorie des Constructive Alignment beschrieben. Nach der theoretischen Fundierung der Kompetenzproblematik wird anhand eines Formulierungsmodells ein Prozess zur Erarbeitung beobachtbarer Lernergebnisse dargestellt. Die Diskussion der Projektziele und Erfahrungen in der Umsetzung und Evaluierung unterstreichen die Chancen und Herausforderungen f{\"u}r eine Steigerung der Studienqualit{\"a}t.},
language = {de}
}
@phdthesis{Seuring2000,
author = {Seuring, Markus},
title = {Output space compaction for testing and concurrent checking},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-0000165},
school = {Universit{\"a}t Potsdam},
year = {2000},
abstract = {In der Dissertation werden neue Entwurfsmethoden f{\"u}r Kompaktoren f{\"u}r die Ausg{\"a}nge von digitalen Schaltungen beschrieben, die die Anzahl der zu testenden Ausg{\"a}nge drastisch verkleinern und dabei die Testbarkeit der Schaltungen nur wenig oder gar nicht verschlechtern. Der erste Teil der Arbeit behandelt f{\"u}r kombinatorische Schaltungen Methoden, die die Struktur der Schaltungen beim Entwurf der Kompaktoren ber{\"u}cksichtigen. Verschiedene Algorithmen zur Analyse von Schaltungsstrukturen werden zum ersten Mal vorgestellt und untersucht. Die Komplexit{\"a}t der vorgestellten Verfahren zur Erzeugung von Kompaktoren ist linear bez{\"u}glich der Anzahl der Gatter in der Schaltung und ist damit auf sehr große Schaltungen anwendbar. Im zweiten Teil wird erstmals ein solches Verfahren f{\"u}r sequentielle Schaltkreise beschrieben. Dieses Verfahren baut im wesentlichen auf das erste auf. Der dritte Teil beschreibt eine Entwurfsmethode, die keine Informationen {\"u}ber die interne Struktur der Schaltung oder {\"u}ber das zugrundeliegende Fehlermodell ben{\"o}tigt. Der Entwurf basiert alleine auf einem vorgegebenen Satz von Testvektoren und die dazugeh{\"o}renden Testantworten der fehlerfreien Schaltung. Ein nach diesem Verfahren erzeugter Kompaktor maskiert keinen der Fehler, die durch das Testen mit den vorgegebenen Vektoren an den Ausg{\"a}ngen der Schaltung beobachtbar sind.},
language = {en}
}
@article{Romeike2010,
author = {Romeike, Ralf},
title = {Output statt Input},
series = {Commentarii informaticae didacticae : (CID)},
journal = {Commentarii informaticae didacticae : (CID)},
number = {4},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-64317},
pages = {35 -- 46},
year = {2010},
abstract = {Die in der Fachdidaktik Informatik im Zusammenhang mit den Bildungsstandards seit Jahren diskutierte Outputorientierung wird mittelfristig auch f{\"u}r die Hochschullehre verbindlich. Diese {\"A}nderung kann als Chance aufgefasst werden, aktuellen Problemen der Informatiklehre gezielt entgegenzuwirken. Basierend auf der Theorie des Constructive Alignment wird vorgeschlagen, im Zusammenhang mit der Outputorientierung eine Abstimmung von intendierter Kompetenz, Lernaktivit{\"a}t und Pr{\"u}fung vorzunehmen. Zus{\"a}tzlich profitieren Lehramtsstudenten von den im eigenen Lernprozess erworbenen Erfahrungen im Umgang mit Kompetenzen: wie diese formuliert, erarbeitet und gepr{\"u}ft werden. Anforderungen an die Formulierung von Kompetenzen werden untersucht, mit Beispielen belegt und M{\"o}glichkeiten zur Klassifizierung angeregt. Ein Austausch in den Fachbereichen und Fachdidaktiken {\"u}ber die individuell festgelegten Kompetenzen wird vorgeschlagen, um die hochschuldidaktische Diskussion zu bereichern.},
language = {de}
}
@phdthesis{Prasse2016,
author = {Prasse, Paul},
title = {Pattern recognition for computer security},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-100251},
school = {Universit{\"a}t Potsdam},
pages = {VI, 75},
year = {2016},
abstract = {Computer Security deals with the detection and mitigation of threats to computer networks, data, and computing hardware. This thesis addresses the following two computer security problems: email spam campaign and malware detection. Email spam campaigns can easily be generated using popular dissemination tools by specifying simple grammars that serve as message templates. A grammar is disseminated to nodes of a bot net, the nodes create messages by instantiating the grammar at random. Email spam campaigns can encompass huge data volumes and therefore pose a threat to the stability of the infrastructure of email service providers that have to store them. Malware -software that serves a malicious purpose- is affecting web servers, client computers via active content, and client computers through executable files. Without the help of malware detection systems it would be easy for malware creators to collect sensitive information or to infiltrate computers. The detection of threats -such as email-spam messages, phishing messages, or malware- is an adversarial and therefore intrinsically difficult problem. Threats vary greatly and evolve over time. The detection of threats based on manually-designed rules is therefore difficult and requires a constant engineering effort. Machine-learning is a research area that revolves around the analysis of data and the discovery of patterns that describe aspects of the data. Discriminative learning methods extract prediction models from data that are optimized to predict a target attribute as accurately as possible. Machine-learning methods hold the promise of automatically identifying patterns that robustly and accurately detect threats. This thesis focuses on the design and analysis of discriminative learning methods for the two computer-security problems under investigation: email-campaign and malware detection. The first part of this thesis addresses email-campaign detection. We focus on regular expressions as a syntactic framework, because regular expressions are intuitively comprehensible by security engineers and administrators, and they can be applied as a detection mechanism in an extremely efficient manner. In this setting, a prediction model is provided with exemplary messages from an email-spam campaign. The prediction model has to generate a regular expression that reveals the syntactic pattern that underlies the entire campaign, and that a security engineers finds comprehensible and feels confident enough to use the expression to blacklist further messages at the email server. We model this problem as two-stage learning problem with structured input and output spaces which can be solved using standard cutting plane methods. Therefore we develop an appropriate loss function, and derive a decoder for the resulting optimization problem. The second part of this thesis deals with the problem of predicting whether a given JavaScript or PHP file is malicious or benign. Recent malware analysis techniques use static or dynamic features, or both. In fully dynamic analysis, the software or script is executed and observed for malicious behavior in a sandbox environment. By contrast, static analysis is based on features that can be extracted directly from the program file. In order to bypass static detection mechanisms, code obfuscation techniques are used to spread a malicious program file in many different syntactic variants. Deobfuscating the code before applying a static classifier can be subjected to mostly static code analysis and can overcome the problem of obfuscated malicious code, but on the other hand increases the computational costs of malware detection by an order of magnitude. In this thesis we present a cascaded architecture in which a classifier first performs a static analysis of the original code and -based on the outcome of this first classification step- the code may be deobfuscated and classified again. We explore several types of features including token \$n\$-grams, orthogonal sparse bigrams, subroutine-hashings, and syntax-tree features and study the robustness of detection methods and feature types against the evolution of malware over time. The developed tool scans very large file collections quickly and accurately. Each model is evaluated on real-world data and compared to reference methods. Our approach of inferring regular expressions to filter emails belonging to an email spam campaigns leads to models with a high true-positive rate at a very low false-positive rate that is an order of magnitude lower than that of a commercial content-based filter. Our presented system -REx-SVMshort- is being used by a commercial email service provider and complements content-based and IP-address based filtering. Our cascaded malware detection system is evaluated on a high-quality data set of almost 400,000 conspicuous PHP files and a collection of more than 1,00,000 JavaScript files. From our case study we can conclude that our system can quickly and accurately process large data collections at a low false-positive rate.},
language = {en}
}
@phdthesis{Ahmad2014,
author = {Ahmad, Nadeem},
title = {People centered HMI's for deaf and functionally illiterate users},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-70391},
school = {Universit{\"a}t Potsdam},
year = {2014},
abstract = {The objective and motivation behind this research is to provide applications with easy-to-use interfaces to communities of deaf and functionally illiterate users, which enables them to work without any human assistance. Although recent years have witnessed technological advancements, the availability of technology does not ensure accessibility to information and communication technologies (ICT). Extensive use of text from menus to document contents means that deaf or functionally illiterate can not access services implemented on most computer software. Consequently, most existing computer applications pose an accessibility barrier to those who are unable to read fluently. Online technologies intended for such groups should be developed in continuous partnership with primary users and include a thorough investigation into their limitations, requirements and usability barriers. In this research, I investigated existing tools in voice, web and other multimedia technologies to identify learning gaps and explored ways to enhance the information literacy for deaf and functionally illiterate users. I worked on the development of user-centered interfaces to increase the capabilities of deaf and low literacy users by enhancing lexical resources and by evaluating several multimedia interfaces for them. The interface of the platform-independent Italian Sign Language (LIS) Dictionary has been developed to enhance the lexical resources for deaf users. The Sign Language Dictionary accepts Italian lemmas as input and provides their representation in the Italian Sign Language as output. The Sign Language dictionary has 3082 signs as set of Avatar animations in which each sign is linked to a corresponding Italian lemma. I integrated the LIS lexical resources with MultiWordNet (MWN) database to form the first LIS MultiWordNet(LMWN). LMWN contains information about lexical relations between words, semantic relations between lexical concepts (synsets), correspondences between Italian and sign language lexical concepts and semantic fields (domains). The approach enhances the deaf users' understanding of written Italian language and shows that a relatively small set of lexicon can cover a significant portion of MWN. Integration of LIS signs with MWN made it useful tool for computational linguistics and natural language processing. The rule-based translation process from written Italian text to LIS has been transformed into service-oriented system. The translation process is composed of various modules including parser, semantic interpreter, generator, and spatial allocation planner. This translation procedure has been implemented in the Java Application Building Center (jABC), which is a framework for extreme model driven design (XMDD). The XMDD approach focuses on bringing software development closer to conceptual design, so that the functionality of a software solution could be understood by someone who is unfamiliar with programming concepts. The transformation addresses the heterogeneity challenge and enhances the re-usability of the system. For enhancing the e-participation of functionally illiterate users, two detailed studies were conducted in the Republic of Rwanda. In the first study, the traditional (textual) interface was compared with the virtual character-based interactive interface. The study helped to identify usability barriers and users evaluated these interfaces according to three fundamental areas of usability, i.e. effectiveness, efficiency and satisfaction. In another study, we developed four different interfaces to analyze the usability and effects of online assistance (consistent help) for functionally illiterate users and compared different help modes including textual, vocal and virtual character on the performance of semi-literate users. In our newly designed interfaces the instructions were automatically translated in Swahili language. All the interfaces were evaluated on the basis of task accomplishment, time consumption, System Usability Scale (SUS) rating and number of times the help was acquired. The results show that the performance of semi-literate users improved significantly when using the online assistance. The dissertation thus introduces a new development approach in which virtual characters are used as additional support for barely literate or naturally challenged users. Such components enhanced the application utility by offering a variety of services like translating contents in local language, providing additional vocal information, and performing automatic translation from text to sign language. Obviously, there is no such thing as one design solution that fits for all in the underlying domain. Context sensitivity, literacy and mental abilities are key factors on which I concentrated and the results emphasize that computer interfaces must be based on a thoughtful definition of target groups, purposes and objectives.},
language = {en}
}
@article{SchirmerRick2013,
author = {Schirmer, Ingrid and Rick, Detlef},
title = {Pers{\"o}nlichkeitsbildung und informatische Professionalisierung},
series = {Commentarii informaticae didacticae : (CID)},
journal = {Commentarii informaticae didacticae : (CID)},
number = {5},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-65053},
pages = {160 -- 169},
year = {2013},
language = {de}
}
@misc{Strickroth2019,
author = {Strickroth, Sven},
title = {PLATON},
series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
number = {804},
issn = {1866-8372},
doi = {10.25932/publishup-44188},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-441887},
pages = {28},
year = {2019},
abstract = {Lesson planning is both an important and demanding task—especially as part of teacher training. This paper presents the requirements for a lesson planning system and evaluates existing systems regarding these requirements. One major drawback of existing software tools is that most are limited to a text- or form-based representation of the lesson designs. In this article, a new approach with a graphical, time-based representation with (automatic) analyses methods is proposed and the system architecture and domain model are described in detail. The approach is implemented in an interactive, web-based prototype called PLATON, which additionally supports the management of lessons in units as well as the modelling of teacher and student-generated resources. The prototype was evaluated in a study with 61 prospective teachers (bachelor's and master's preservice teachers as well as teacher trainees in post-university teacher training) in Berlin, Germany, with a focus on usability. The results show that this approach proofed usable for lesson planning and offers positive effects for the perception of time and self-reflection.},
language = {en}
}
@misc{PrasseIversenLienhardetal.2022,
author = {Prasse, Paul and Iversen, Pascal and Lienhard, Matthias and Thedinga, Kristina and Herwig, Ralf and Scheffer, Tobias},
title = {Pre-Training on In Vitro and Fine-Tuning on Patient-Derived Data Improves Deep Neural Networks for Anti-Cancer Drug-Sensitivity Prediction},
series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
issn = {1866-8372},
doi = {10.25932/publishup-57734},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-577341},
pages = {1 -- 14},
year = {2022},
abstract = {Large-scale databases that report the inhibitory capacities of many combinations of candidate drug compounds and cultivated cancer cell lines have driven the development of preclinical drug-sensitivity models based on machine learning. However, cultivated cell lines have devolved from human cancer cells over years or even decades under selective pressure in culture conditions. Moreover, models that have been trained on in vitro data cannot account for interactions with other types of cells. Drug-response data that are based on patient-derived cell cultures, xenografts, and organoids, on the other hand, are not available in the quantities that are needed to train high-capacity machine-learning models. We found that pre-training deep neural network models of drug sensitivity on in vitro drug-sensitivity databases before fine-tuning the model parameters on patient-derived data improves the models' accuracy and improves the biological plausibility of the features, compared to training only on patient-derived data. From our experiments, we can conclude that pre-trained models outperform models that have been trained on the target domains in the vast majority of cases.},
language = {en}
}
@phdthesis{Brueckner2012,
author = {Br{\"u}ckner, Michael},
title = {Prediction games : machine learning in the presence of an adversary},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-203-2},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-60375},
school = {Universit{\"a}t Potsdam},
pages = {x, 121},
year = {2012},
abstract = {In many applications one is faced with the problem of inferring some functional relation between input and output variables from given data. Consider, for instance, the task of email spam filtering where one seeks to find a model which automatically assigns new, previously unseen emails to class spam or non-spam. Building such a predictive model based on observed training inputs (e.g., emails) with corresponding outputs (e.g., spam labels) is a major goal of machine learning. Many learning methods assume that these training data are governed by the same distribution as the test data which the predictive model will be exposed to at application time. That assumption is violated when the test data are generated in response to the presence of a predictive model. This becomes apparent, for instance, in the above example of email spam filtering. Here, email service providers employ spam filters and spam senders engineer campaign templates such as to achieve a high rate of successful deliveries despite any filters. Most of the existing work casts such situations as learning robust models which are unsusceptible against small changes of the data generation process. The models are constructed under the worst-case assumption that these changes are performed such to produce the highest possible adverse effect on the performance of the predictive model. However, this approach is not capable to realistically model the true dependency between the model-building process and the process of generating future data. We therefore establish the concept of prediction games: We model the interaction between a learner, who builds the predictive model, and a data generator, who controls the process of data generation, as an one-shot game. The game-theoretic framework enables us to explicitly model the players' interests, their possible actions, their level of knowledge about each other, and the order at which they decide for an action. We model the players' interests as minimizing their own cost function which both depend on both players' actions. The learner's action is to choose the model parameters and the data generator's action is to perturbate the training data which reflects the modification of the data generation process with respect to the past data. We extensively study three instances of prediction games which differ regarding the order in which the players decide for their action. We first assume that both player choose their actions simultaneously, that is, without the knowledge of their opponent's decision. We identify conditions under which this Nash prediction game has a meaningful solution, that is, a unique Nash equilibrium, and derive algorithms that find the equilibrial prediction model. As a second case, we consider a data generator who is potentially fully informed about the move of the learner. This setting establishes a Stackelberg competition. We derive a relaxed optimization criterion to determine the solution of this game and show that this Stackelberg prediction game generalizes existing prediction models. Finally, we study the setting where the learner observes the data generator's action, that is, the (unlabeled) test data, before building the predictive model. As the test data and the training data may be governed by differing probability distributions, this scenario reduces to learning under covariate shift. We derive a new integrated as well as a two-stage method to account for this data set shift. In case studies on email spam filtering we empirically explore properties of all derived models as well as several existing baseline methods. We show that spam filters resulting from the Nash prediction game as well as the Stackelberg prediction game in the majority of cases outperform other existing baseline methods.},
language = {en}
}
@phdthesis{Haider2013,
author = {Haider, Peter},
title = {Prediction with Mixture Models},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-69617},
school = {Universit{\"a}t Potsdam},
year = {2013},
abstract = {Learning a model for the relationship between the attributes and the annotated labels of data examples serves two purposes. Firstly, it enables the prediction of the label for examples without annotation. Secondly, the parameters of the model can provide useful insights into the structure of the data. If the data has an inherent partitioned structure, it is natural to mirror this structure in the model. Such mixture models predict by combining the individual predictions generated by the mixture components which correspond to the partitions in the data. Often the partitioned structure is latent, and has to be inferred when learning the mixture model. Directly evaluating the accuracy of the inferred partition structure is, in many cases, impossible because the ground truth cannot be obtained for comparison. However it can be assessed indirectly by measuring the prediction accuracy of the mixture model that arises from it. This thesis addresses the interplay between the improvement of predictive accuracy by uncovering latent cluster structure in data, and further addresses the validation of the estimated structure by measuring the accuracy of the resulting predictive model. In the application of filtering unsolicited emails, the emails in the training set are latently clustered into advertisement campaigns. Uncovering this latent structure allows filtering of future emails with very low false positive rates. In order to model the cluster structure, a Bayesian clustering model for dependent binary features is developed in this thesis. Knowing the clustering of emails into campaigns can also aid in uncovering which emails have been sent on behalf of the same network of captured hosts, so-called botnets. This association of emails to networks is another layer of latent clustering. Uncovering this latent structure allows service providers to further increase the accuracy of email filtering and to effectively defend against distributed denial-of-service attacks. To this end, a discriminative clustering model is derived in this thesis that is based on the graph of observed emails. The partitionings inferred using this model are evaluated through their capacity to predict the campaigns of new emails. Furthermore, when classifying the content of emails, statistical information about the sending server can be valuable. Learning a model that is able to make use of it requires training data that includes server statistics. In order to also use training data where the server statistics are missing, a model that is a mixture over potentially all substitutions thereof is developed. Another application is to predict the navigation behavior of the users of a website. Here, there is no a priori partitioning of the users into clusters, but to understand different usage scenarios and design different layouts for them, imposing a partitioning is necessary. The presented approach simultaneously optimizes the discriminative as well as the predictive power of the clusters. Each model is evaluated on real-world data and compared to baseline methods. The results show that explicitly modeling the assumptions about the latent cluster structure leads to improved predictions compared to the baselines. It is beneficial to incorporate a small number of hyperparameters that can be tuned to yield the best predictions in cases where the prediction accuracy can not be optimized directly.},
language = {en}
}
@inproceedings{GeskeWolf2010,
author = {Geske, Ulrich and Wolf, Armin},
title = {Preface},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-41401},
year = {2010},
abstract = {The workshops on (constraint) logic programming (WLP) are the annual meeting of the Society of Logic Programming (GLP e.V.) and bring together researchers interested in logic programming, constraint programming, and related areas like databases, artificial intelligence and operations research. In this decade, previous workshops took place in Dresden (2008), W{\"u}rzburg (2007), Vienna (2006), Ulm (2005), Potsdam (2004), Dresden (2002), Kiel (2001), and W{\"u}rzburg (2000). Contributions to workshops deal with all theoretical, experimental, and application aspects of constraint programming (CP) and logic programming (LP), including foundations of constraint/ logic programming. Some of the special topics are constraint solving and optimization, extensions of functional logic programming, deductive databases, data mining, nonmonotonic reasoning, , interaction of CP/LP with other formalisms like agents, XML, JAVA, program analysis, program transformation, program verification, meta programming, parallelism and concurrency, answer set programming, implementation and software techniques (e.g., types, modularity, design patterns), applications (e.g., in production, environment, education, internet), constraint/logic programming for semantic web systems and applications, reasoning on the semantic web, data modelling for the web, semistructured data, and web query languages.},
language = {en}
}
@phdthesis{Konczak2007,
author = {Konczak, Kathrin},
title = {Preferences in answer set programming},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-12058},
school = {Universit{\"a}t Potsdam},
year = {2007},
abstract = {Answer Set Programming (ASP) emerged in the late 1990s as a new logic programming paradigm, having its roots in nonmonotonic reasoning, deductive databases, and logic programming with negation as failure. The basic idea of ASP is to represent a computational problem as a logic program whose answer sets correspond to solutions, and then to use an answer set solver for finding answer sets of the program. ASP is particularly suited for solving NP-complete search problems. Among these, we find applications to product configuration, diagnosis, and graph-theoretical problems, e.g. finding Hamiltonian cycles. On different lines of ASP research, many extensions of the basic formalism have been proposed. The most intensively studied one is the modelling of preferences in ASP. They constitute a natural and effective way of selecting preferred solutions among a plethora of solutions for a problem. For example, preferences have been successfully used for timetabling, auctioning, and product configuration. In this thesis, we concentrate on preferences within answer set programming. Among several formalisms and semantics for preference handling in ASP, we concentrate on ordered logic programs with the underlying D-, W-, and B-semantics. In this setting, preferences are defined among rules of a logic program. They select preferred answer sets among (standard) answer sets of the underlying logic program. Up to now, those preferred answer sets have been computed either via a compilation method or by meta-interpretation. Hence, the question comes up, whether and how preferences can be integrated into an existing ASP solver. To solve this question, we develop an operational graph-based framework for the computation of answer sets of logic programs. Then, we integrate preferences into this operational approach. We empirically observe that our integrative approach performs in most cases better than the compilation method or meta-interpretation. Another research issue in ASP are optimization methods that remove redundancies, as also found in database query optimizers. For these purposes, the rather recently suggested notion of strong equivalence for ASP can be used. If a program is strongly equivalent to a subprogram of itself, then one can always use the subprogram instead of the original program, a technique which serves as an effective optimization method. Up to now, strong equivalence has not been considered for logic programs with preferences. In this thesis, we tackle this issue and generalize the notion of strong equivalence to ordered logic programs. We give necessary and sufficient conditions for the strong equivalence of two ordered logic programs. Furthermore, we provide program transformations for ordered logic programs and show in how far preferences can be simplified. Finally, we present two new applications for preferences within answer set programming. First, we define new procedures for group decision making, which we apply to the problem of scheduling a group meeting. As a second new application, we reconstruct a linguistic problem appearing in German dialects within ASP. Regarding linguistic studies, there is an ongoing debate about how unique the rule systems of language are in human cognition. The reconstruction of grammatical regularities with tools from computer science has consequences for this debate: if grammars can be modelled this way, then they share core properties with other non-linguistic rule systems.},
language = {en}
}
@phdthesis{Scheffler2013,
author = {Scheffler, Thomas},
title = {Privacy enforcement with data owner-defined policies},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-67939},
school = {Universit{\"a}t Potsdam},
year = {2013},
abstract = {This thesis proposes a privacy protection framework for the controlled distribution and use of personal private data. The framework is based on the idea that privacy policies can be set directly by the data owner and can be automatically enforced against the data user. Data privacy continues to be a very important topic, as our dependency on electronic communication maintains its current growth, and private data is shared between multiple devices, users and locations. The growing amount and the ubiquitous availability of personal private data increases the likelihood of data misuse. Early privacy protection techniques, such as anonymous email and payment systems have focused on data avoidance and anonymous use of services. They did not take into account that data sharing cannot be avoided when people participate in electronic communication scenarios that involve social interactions. This leads to a situation where data is shared widely and uncontrollably and in most cases the data owner has no control over further distribution and use of personal private data. Previous efforts to integrate privacy awareness into data processing workflows have focused on the extension of existing access control frameworks with privacy aware functions or have analysed specific individual problems such as the expressiveness of policy languages. So far, very few implementations of integrated privacy protection mechanisms exist and can be studied to prove their effectiveness for privacy protection. Second level issues that stem from practical application of the implemented mechanisms, such as usability, life-time data management and changes in trustworthiness have received very little attention so far, mainly because they require actual implementations to be studied. Most existing privacy protection schemes silently assume that it is the privilege of the data user to define the contract under which personal private data is released. Such an approach simplifies policy management and policy enforcement for the data user, but leaves the data owner with a binary decision to submit or withhold his or her personal data based on the provided policy. We wanted to empower the data owner to express his or her privacy preferences through privacy policies that follow the so-called Owner-Retained Access Control (ORAC) model. ORAC has been proposed by McCollum, et al. as an alternate access control mechanism that leaves the authority over access decisions by the originator of the data. The data owner is given control over the release policy for his or her personal data, and he or she can set permissions or restrictions according to individually perceived trust values. Such a policy needs to be expressed in a coherent way and must allow the deterministic policy evaluation by different entities. The privacy policy also needs to be communicated from the data owner to the data user, so that it can be enforced. Data and policy are stored together as a Protected Data Object that follows the Sticky Policy paradigm as defined by Mont, et al. and others. We developed a unique policy combination approach that takes usability aspects for the creation and maintenance of policies into consideration. Our privacy policy consists of three parts: A Default Policy provides basic privacy protection if no specific rules have been entered by the data owner. An Owner Policy part allows the customisation of the default policy by the data owner. And a so-called Safety Policy guarantees that the data owner cannot specify disadvantageous policies, which, for example, exclude him or her from further access to the private data. The combined evaluation of these three policy-parts yields the necessary access decision. The automatic enforcement of privacy policies in our protection framework is supported by a reference monitor implementation. We started our work with the development of a client-side protection mechanism that allows the enforcement of data-use restrictions after private data has been released to the data user. The client-side enforcement component for data-use policies is based on a modified Java Security Framework. Privacy policies are translated into corresponding Java permissions that can be automatically enforced by the Java Security Manager. When we later extended our work to implement server-side protection mechanisms, we found several drawbacks for the privacy enforcement through the Java Security Framework. We solved this problem by extending our reference monitor design to use Aspect-Oriented Programming (AOP) and the Java Reflection API to intercept data accesses in existing applications and provide a way to enforce data owner-defined privacy policies for business applications.},
language = {en}
}
@phdthesis{AbdelwahabHusseinAbdelwahabElsayed2019,
author = {Abdelwahab Hussein Abdelwahab Elsayed, Ahmed},
title = {Probabilistic, deep, and metric learning for biometric identification from eye movements},
doi = {10.25932/publishup-46798},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-467980},
school = {Universit{\"a}t Potsdam},
pages = {vi, 65},
year = {2019},
abstract = {A central insight from psychological studies on human eye movements is that eye movement patterns are highly individually characteristic. They can, therefore, be used as a biometric feature, that is, subjects can be identified based on their eye movements. This thesis introduces new machine learning methods to identify subjects based on their eye movements while viewing arbitrary content. The thesis focuses on probabilistic modeling of the problem, which has yielded the best results in the most recent literature. The thesis studies the problem in three phases by proposing a purely probabilistic, probabilistic deep learning, and probabilistic deep metric learning approach. In the first phase, the thesis studies models that rely on psychological concepts about eye movements. Recent literature illustrates that individual-specific distributions of gaze patterns can be used to accurately identify individuals. In these studies, models were based on a simple parametric family of distributions. Such simple parametric models can be robustly estimated from sparse data, but have limited flexibility to capture the differences between individuals. Therefore, this thesis proposes a semiparametric model of gaze patterns that is flexible yet robust for individual identification. These patterns can be understood as domain knowledge derived from psychological literature. Fixations and saccades are examples of simple gaze patterns. The proposed semiparametric densities are drawn under a Gaussian process prior centered at a simple parametric distribution. Thus, the model will stay close to the parametric class of densities if little data is available, but it can also deviate from this class if enough data is available, increasing the flexibility of the model. The proposed method is evaluated on a large-scale dataset, showing significant improvements over the state-of-the-art. Later, the thesis replaces the model based on gaze patterns derived from psychological concepts with a deep neural network that can learn more informative and complex patterns from raw eye movement data. As previous work has shown that the distribution of these patterns across a sequence is informative, a novel statistical aggregation layer called the quantile layer is introduced. It explicitly fits the distribution of deep patterns learned directly from the raw eye movement data. The proposed deep learning approach is end-to-end learnable, such that the deep model learns to extract informative, short local patterns while the quantile layer learns to approximate the distributions of these patterns. Quantile layers are a generic approach that can converge to standard pooling layers or have a more detailed description of the features being pooled, depending on the problem. The proposed model is evaluated in a large-scale study using the eye movements of subjects viewing arbitrary visual input. The model improves upon the standard pooling layers and other statistical aggregation layers proposed in the literature. It also improves upon the state-of-the-art eye movement biometrics by a wide margin. Finally, for the model to identify any subject — not just the set of subjects it is trained on — a metric learning approach is developed. Metric learning learns a distance function over instances. The metric learning model maps the instances into a metric space, where sequences of the same individual are close, and sequences of different individuals are further apart. This thesis introduces a deep metric learning approach with distributional embeddings. The approach represents sequences as a set of continuous distributions in a metric space; to achieve this, a new loss function based on Wasserstein distances is introduced. The proposed method is evaluated on multiple domains besides eye movement biometrics. This approach outperforms the state of the art in deep metric learning in several domains while also outperforming the state of the art in eye movement biometrics.},
language = {en}
}
@inproceedings{OPUS4-3955,
title = {Proceedings of the 23rd Workshop on (Constraint) Logic Programming 2009},
editor = {Geske, Ulrich and Wolf, Armin},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-026-7},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-37977},
pages = {187},
year = {2010},
abstract = {The workshops on (constraint) logic programming (WLP) are the annual meeting of the Society of Logic Programming (GLP e.V.) and bring together researchers interested in logic programming, constraint programming, and related areas like databases, artificial intelligence and operations research. The 23rd WLP was held in Potsdam at September 15 - 16, 2009. The topics of the presentations of WLP2009 were grouped into the major areas: Databases, Answer Set Programming, Theory and Practice of Logic Programming as well as Constraints and Constraint Handling Rules.},
language = {en}
}
@article{Kalas2015,
author = {Kalas, Ivan},
title = {Programming at Pre-primary and Primary Levels},
series = {KEYCIT 2014 - Key Competencies in Informatics and ICT},
journal = {KEYCIT 2014 - Key Competencies in Informatics and ICT},
number = {7},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-82587},
pages = {29 -- 31},
year = {2015},
language = {en}
}
@article{OrBach2015,
author = {Or-Bach, Rachel},
title = {Programming for Non-Programmers},
series = {KEYCIT 2014 - Key Competencies in Informatics and ICT},
journal = {KEYCIT 2014 - Key Competencies in Informatics and ICT},
number = {7},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-82875},
pages = {335 -- 342},
year = {2015},
abstract = {The study reported in this paper involved the employment of specific in-class exercises using a Personal Response System (PRS). These exercises were designed with two goals: to enhance students' capabilities of tracing a given code and of explaining a given code in natural language with some abstraction. The paper presents evidence from the actual use of the PRS along with students' subjective impressions regarding both the use of the PRS and the special exercises. The conclusions from the findings are followed with a short discussion on benefits of PRS-based mental processing exercises for learning programming and beyond.},
language = {en}
}
@article{VossebergCzernikErbetal.2015,
author = {Vosseberg, Karin and Czernik, Sofie and Erb, Ulrike and Vielhaber, Michael},
title = {Projektorientierte Studieneingangsphase},
series = {HDI 2014 : Gestalten von {\"U}berg{\"a}ngen},
volume = {2015},
journal = {HDI 2014 : Gestalten von {\"U}berg{\"a}ngen},
number = {9},
editor = {Schubert, Sigrid and Schwill, Andreas},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-84730},
pages = {169 -- 177},
year = {2015},
abstract = {Ziel einer neuen Studieneingangsphase ist, den Studierenden bis zum Ende des ersten Semesters ein vielf{\"a}ltiges Berufsbild der Informatik und Wirtschaftsinformatik mit dem breiten Aufgabenspektrum aufzubl{\"a}ttern und damit die Zusammenh{\"a}nge zwischen den einzelnen Modulen des Curriculums zu verdeutlichen. Die Studierenden sollen in die Lage versetzt werden, sehr eigenst{\"a}ndig die Planung und Gestaltung ihres Studiums in die Hand zu nehmen.},
language = {de}
}
@phdthesis{Gebser2011,
author = {Gebser, Martin},
title = {Proof theory and algorithms for answer set programming},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-55425},
school = {Universit{\"a}t Potsdam},
year = {2011},
abstract = {Answer Set Programming (ASP) is an emerging paradigm for declarative programming, in which a computational problem is specified by a logic program such that particular models, called answer sets, match solutions. ASP faces a growing range of applications, demanding for high-performance tools able to solve complex problems. ASP integrates ideas from a variety of neighboring fields. In particular, automated techniques to search for answer sets are inspired by Boolean Satisfiability (SAT) solving approaches. While the latter have firm proof-theoretic foundations, ASP lacks formal frameworks for characterizing and comparing solving methods. Furthermore, sophisticated search patterns of modern SAT solvers, successfully applied in areas like, e.g., model checking and verification, are not yet established in ASP solving. We address these deficiencies by, for one, providing proof-theoretic frameworks that allow for characterizing, comparing, and analyzing approaches to answer set computation. For another, we devise modern ASP solving algorithms that integrate and extend state-of-the-art techniques for Boolean constraint solving. We thus contribute to the understanding of existing ASP solving approaches and their interconnections as well as to their enhancement by incorporating sophisticated search patterns. The central idea of our approach is to identify atomic as well as composite constituents of a propositional logic program with Boolean variables. This enables us to describe fundamental inference steps, and to selectively combine them in proof-theoretic characterizations of various ASP solving methods. In particular, we show that different concepts of case analyses applied by existing ASP solvers implicate mutual exponential separations regarding their best-case complexities. We also develop a generic proof-theoretic framework amenable to language extensions, and we point out that exponential separations can likewise be obtained due to case analyses on them. We further exploit fundamental inference steps to derive Boolean constraints characterizing answer sets. They enable the conception of ASP solving algorithms including search patterns of modern SAT solvers, while also allowing for direct technology transfers between the areas of ASP and SAT solving. Beyond the search for one answer set of a logic program, we address the enumeration of answer sets and their projections to a subvocabulary, respectively. The algorithms we develop enable repetition-free enumeration in polynomial space without being intrusive, i.e., they do not necessitate any modifications of computations before an answer set is found. Our approach to ASP solving is implemented in clasp, a state-of-the-art Boolean constraint solver that has successfully participated in recent solver competitions. Although we do here not address the implementation techniques of clasp or all of its features, we present the principles of its success in the context of ASP solving.},
language = {en}
}
@article{WegnerZenderLucke2015,
author = {Wegner, Christian and Zender, Raphael and Lucke, Ulrike},
title = {ProtoSense},
series = {KEYCIT 2014 - Key Competencies in Informatics and ICT},
journal = {KEYCIT 2014 - Key Competencies in Informatics and ICT},
number = {7},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-82970},
pages = {405 -- 407},
year = {2015},
language = {en}
}
@article{FrenkelWeicker2010,
author = {Frenkel, Marcus and Weicker, Karsten},
title = {Pseudo},
series = {Commentarii informaticae didacticae : (CID)},
journal = {Commentarii informaticae didacticae : (CID)},
number = {4},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-64328},
pages = {47 -- 52},
year = {2010},
abstract = {Pseudo ist eine auf Pseudocode basierende Programmiersprache, welche in der akademischen Lehre zum Einsatz kommen und hier die Vermittlung und Untersuchung von Algorithmen und Datenstrukturen unterst{\"u}tzen soll. Dieser Beitrag geht auf die Besonderheiten der Sprache sowie m{\"o}gliche didaktische Szenarien ein.},
language = {de}
}
@phdthesis{Kluth2011,
author = {Kluth, Stephan},
title = {Quantitative modeling and analysis with FMC-QE},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-52987},
school = {Universit{\"a}t Potsdam},
year = {2011},
abstract = {The modeling and evaluation calculus FMC-QE, the Fundamental Modeling Concepts for Quanti-tative Evaluation [1], extends the Fundamental Modeling Concepts (FMC) for performance modeling and prediction. In this new methodology, the hierarchical service requests are in the main focus, because they are the origin of every service provisioning process. Similar to physics, these service requests are a tuple of value and unit, which enables hierarchical service request transformations at the hierarchical borders and therefore the hierarchical modeling. Through reducing the model complexity of the models by decomposing the system in different hierarchical views, the distinction between operational and control states and the calculation of the performance values on the assumption of the steady state, FMC-QE has a scalable applica-bility on complex systems. According to FMC, the system is modeled in a 3-dimensional hierarchical representation space, where system performance parameters are described in three arbitrarily fine-grained hierarchi-cal bipartite diagrams. The hierarchical service request structures are modeled in Entity Relationship Diagrams. The static server structures, divided into logical and real servers, are de-scribed as Block Diagrams. The dynamic behavior and the control structures are specified as Petri Nets, more precisely Colored Time Augmented Petri Nets. From the structures and pa-rameters of the performance model, a hierarchical set of equations is derived. The calculation of the performance values is done on the assumption of stationary processes and is based on fundamental laws of the performance analysis: Little's Law and the Forced Traffic Flow Law. Little's Law is used within the different hierarchical levels (horizontal) and the Forced Traffic Flow Law is the key to the dependencies among the hierarchical levels (vertical). This calculation is suitable for complex models and allows a fast (re-)calculation of different performance scenarios in order to support development and configuration decisions. Within the Research Group Zorn at the Hasso Plattner Institute, the work is embedded in a broader research in the development of FMC-QE. While this work is concentrated on the theoretical background, description and definition of the methodology as well as the extension and validation of the applicability, other topics are in the development of an FMC-QE modeling and evaluation tool and the usage of FMC-QE in the design of an adaptive transport layer in order to fulfill Quality of Service and Service Level Agreements in volatile service based environments. This thesis contains a state-of-the-art, the description of FMC-QE as well as extensions of FMC-QE in representative general models and case studies. In the state-of-the-art part of the thesis in chapter 2, an overview on existing Queueing Theory and Time Augmented Petri Net models and other quantitative modeling and evaluation languages and methodologies is given. Also other hierarchical quantitative modeling frameworks will be considered. The description of FMC-QE in chapter 3 consists of a summary of the foundations of FMC-QE, basic definitions, the graphical notations, the FMC-QE Calculus and the modeling of open queueing networks as an introductory example. The extensions of FMC-QE in chapter 4 consist of the integration of the summation method in order to support the handling of closed networks and the modeling of multiclass and semaphore scenarios. Furthermore, FMC-QE is compared to other performance modeling and evaluation approaches. In the case study part in chapter 5, proof-of-concept examples, like the modeling of a service based search portal, a service based SAP NetWeaver application and the Axis2 Web service framework will be provided. Finally, conclusions are given by a summary of contributions and an outlook on future work in chapter 6. [1] Werner Zorn. FMC-QE - A New Approach in Quantitative Modeling. In Hamid R. Arabnia, editor, Procee-dings of the International Conference on Modeling, Simulation and Visualization Methods (MSV 2007) within WorldComp '07, pages 280 - 287, Las Vegas, NV, USA, June 2007. CSREA Press. ISBN 1-60132-029-9.},
language = {en}
}
@misc{Lunemann2006,
type = {Master Thesis},
author = {Lunemann, Carolin},
title = {Quantum cryptography : security analysis of multiuser quantum communication with embedded authentication},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-12756},
school = {Universit{\"a}t Potsdam},
year = {2006},
abstract = {Three quantum cryptographic protocols of multiuser quantum networks with embedded authentication, allowing quantum key distribution or quantum direct communication, are discussed in this work. The security of the protocols against different types of attacks is analysed with a focus on various impersonation attacks and the man-in-the-middle attack. On the basis of the security analyses several improvements are suggested and implemented in order to adjust the investigated vulnerabilities. Furthermore, the impact of the eavesdropping test procedure on impersonation attacks is outlined. The framework of a general eavesdropping test is proposed to provide additional protection against security risks in impersonation attacks.},
language = {en}
}
@article{FietkauKindsmuellerGoettel2015,
author = {Fietkau, Julian and Kindsm{\"u}ller, Martin Christof and G{\"o}ttel, Timo},
title = {Rapid Prototyping von Interaktionskonzepten in der universit{\"a}ren MCI-Lehre},
series = {HDI 2014 : Gestalten von {\"U}berg{\"a}ngen},
volume = {2015},
journal = {HDI 2014 : Gestalten von {\"U}berg{\"a}ngen},
number = {9},
editor = {Schubert, Sigrid and Schwill, Andreas},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-84718},
pages = {153 -- 160},
year = {2015},
abstract = {In der Lehre zur MCI (Mensch-Computer-Interaktion) stellt sich immer wieder die Herausforderung, praktische {\"U}bungen mit spannenden Ergebnissen durchzuf{\"u}hren, die sich dennoch nicht in technischen Details verlieren sondern MCI-fokussiert bleiben. Im Lehrmodul „Interaktionsdesign" an der Universit{\"a}t Hamburg werden von Studierenden innerhalb von drei Wochen prototypische Interaktionskonzepte f{\"u}r das Spiel Neverball entworfen und praktisch umgesetzt. Anders als in den meisten Grundlagenkursen zur MCI werden hier nicht Mock-Ups, sondern lauff{\"a}hige Software entwickelt. Um dies innerhalb der Projektzeit zu erm{\"o}glichen, wurde Neverball um eine TCP-basierte Schnittstelle erweitert. So entf{\"a}llt die aufw{\"a}ndige Einarbeitung in den Quellcode des Spiels und die Studierenden k{\"o}nnen sich auf ihre Interaktionsprototypen konzentrieren. Wir beschreiben die Erfahrungen aus der mehrmaligen Durchf{\"u}hrung des Projektes und erl{\"a}utern unser Vorgehen bei der Umsetzung. Die Ergebnisse sollen Lehrende im Bereich MCI unterst{\"u}tzen, {\"a}hnliche praxisorientierte {\"U}bungen mit Ergebnissen „zum Anfassen" zu gestalten.},
language = {de}
}
@phdthesis{Buchholz2006,
author = {Buchholz, Henrik},
title = {Real-time visualization of 3D city models},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-13337},
school = {Universit{\"a}t Potsdam},
year = {2006},
abstract = {An increasing number of applications requires user interfaces that facilitate the handling of large geodata sets. Using virtual 3D city models, complex geospatial information can be communicated visually in an intuitive way. Therefore, real-time visualization of virtual 3D city models represents a key functionality for interactive exploration, presentation, analysis, and manipulation of geospatial data. This thesis concentrates on the development and implementation of concepts and techniques for real-time city model visualization. It discusses rendering algorithms as well as complementary modeling concepts and interaction techniques. Particularly, the work introduces a new real-time rendering technique to handle city models of high complexity concerning texture size and number of textures. Such models are difficult to handle by current technology, primarily due to two problems: - Limited texture memory: The amount of simultaneously usable texture data is limited by the memory of the graphics hardware. - Limited number of textures: Using several thousand different textures simultaneously causes significant performance problems due to texture switch operations during rendering. The multiresolution texture atlases approach, introduced in this thesis, overcomes both problems. During rendering, it permanently maintains a small set of textures that are sufficient for the current view and the screen resolution available. The efficiency of multiresolution texture atlases is evaluated in performance tests. To summarize, the results demonstrate that the following goals have been achieved: - Real-time rendering becomes possible for 3D scenes whose amount of texture data exceeds the main memory capacity. - Overhead due to texture switches is kept permanently low, so that the number of different textures has no significant effect on the rendering frame rate. Furthermore, this thesis introduces two new approaches for real-time city model visualization that use textures as core visualization elements: - An approach for visualization of thematic information. - An approach for illustrative visualization of 3D city models. Both techniques demonstrate that multiresolution texture atlases provide a basic functionality for the development of new applications and systems in the domain of city model visualization.},
language = {en}
}
@phdthesis{Videla2014,
author = {Videla, Santiago},
title = {Reasoning on the response of logical signaling networks with answer set programming},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-71890},
school = {Universit{\"a}t Potsdam},
year = {2014},
abstract = {Deciphering the functioning of biological networks is one of the central tasks in systems biology. In particular, signal transduction networks are crucial for the understanding of the cellular response to external and internal perturbations. Importantly, in order to cope with the complexity of these networks, mathematical and computational modeling is required. We propose a computational modeling framework in order to achieve more robust discoveries in the context of logical signaling networks. More precisely, we focus on modeling the response of logical signaling networks by means of automated reasoning using Answer Set Programming (ASP). ASP provides a declarative language for modeling various knowledge representation and reasoning problems. Moreover, available ASP solvers provide several reasoning modes for assessing the multitude of answer sets. Therefore, leveraging its rich modeling language and its highly efficient solving capacities, we use ASP to address three challenging problems in the context of logical signaling networks: learning of (Boolean) logical networks, experimental design, and identification of intervention strategies. Overall, the contribution of this thesis is three-fold. Firstly, we introduce a mathematical framework for characterizing and reasoning on the response of logical signaling networks. Secondly, we contribute to a growing list of successful applications of ASP in systems biology. Thirdly, we present a software providing a complete pipeline for automated reasoning on the response of logical signaling networks.},
language = {en}
}
@article{DrewsSchirmerMorisseetal.2013,
author = {Drews, Paul and Schirmer, Ingrid and Morisse, Marcel and Sagawe, Arno and Rolf, Arno},
title = {Reflexionsdialog mit DialogueMaps},
series = {Commentarii informaticae didacticae : (CID)},
journal = {Commentarii informaticae didacticae : (CID)},
number = {5},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-64983},
pages = {117 -- 123},
year = {2013},
abstract = {In einigen Bereichen der Informatiklehre ist es m{\"o}glich, die pers{\"o}nlichen Erfahrungen der Studierenden im Umgang mit Informationstechnik aufzugreifen und vor dem Hintergrund theoretischer Konzepte aus der Literatur gemeinsam mit ihnen zu reflektieren. Das hier vorgestellte Lehrkonzept des Reflexionsdialogs erstreckt sich {\"u}ber drei Seminartermine und vorbereitende Selbstlernphasen. Unterst{\"u}tzt wird das Konzept durch DialogueMaps, eine Software zur Visualisierung komplexer Sachverhalte und zur Unterst{\"u}tzung interaktiver Dialoge. Dieser Beitrag beschreibt die Hintergr{\"u}nde des Lehrkonzeptes, das Lehrkonzept selbst sowie die inhaltliche Ausgestaltung im Rahmen eines Mastermoduls „Computergest{\"u}tzte Kooperation".},
language = {de}
}
@phdthesis{Mahr2012,
author = {Mahr, Philipp},
title = {Resource efficient communication in network-based reconfigurable on-chip systems},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-59914},
school = {Universit{\"a}t Potsdam},
year = {2012},
abstract = {The constantly growing capacity of reconfigurable devices allows simultaneous execution of complex applications on those devices. The mere diversity of applications deems it impossible to design an interconnection network matching the requirements of every possible application perfectly, leading to suboptimal performance in many cases. However, the architecture of the interconnection network is not the only aspect affecting performance of communication. The resource manager places applications on the device and therefore influences latency between communicating partners and overall network load. Communication protocols affect performance by introducing data and processing overhead putting higher load on the network and increasing resource demand. Approaching communication holistically not only considers the architecture of the interconnect, but communication-aware resource management, communication protocols and resource usage just as well. Incorporation of different parts of a reconfigurable system during design- and runtime and optimizing them with respect to communication demand results in more resource efficient communication. Extensive evaluation shows enhanced performance and flexibility, if communication on reconfigurable devices is regarded in a holistic fashion.},
language = {en}
}
@misc{AguadoCabalarFandinnoetal.2019,
author = {Aguado, Felicidad and Cabalar, Pedro and Fandinno, Jorge and Pearce, David and Perez, Gilberto and Vidal, Concepcion},
title = {Revisiting explicit negation in answer set programming},
series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
number = {1104},
issn = {1866-8372},
doi = {10.25932/publishup-46969},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-469697},
pages = {908 -- 924},
year = {2019},
abstract = {A common feature in Answer Set Programming is the use of a second negation, stronger than default negation and sometimes called explicit, strong or classical negation. This explicit negation is normally used in front of atoms, rather than allowing its use as a regular operator. In this paper we consider the arbitrary combination of explicit negation with nested expressions, as those defined by Lifschitz, Tang and Turner. We extend the concept of reduct for this new syntax and then prove that it can be captured by an extension of Equilibrium Logic with this second negation. We study some properties of this variant and compare to the already known combination of Equilibrium Logic with Nelson's strong negation.},
language = {en}
}
@phdthesis{Raetsch2001,
author = {R{\"a}tsch, Gunnar},
title = {Robust boosting via convex optimization},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-0000399},
school = {Universit{\"a}t Potsdam},
year = {2001},
abstract = {In dieser Arbeit werden statistische Lernprobleme betrachtet. Lernmaschinen extrahieren Informationen aus einer gegebenen Menge von Trainingsmustern, so daß sie in der Lage sind, Eigenschaften von bisher ungesehenen Mustern - z.B. eine Klassenzugeh{\"o}rigkeit - vorherzusagen. Wir betrachten den Fall, bei dem die resultierende Klassifikations- oder Regressionsregel aus einfachen Regeln - den Basishypothesen - zusammengesetzt ist. Die sogenannten Boosting Algorithmen erzeugen iterativ eine gewichtete Summe von Basishypothesen, die gut auf ungesehenen Mustern vorhersagen. Die Arbeit behandelt folgende Sachverhalte: o Die zur Analyse von Boosting-Methoden geeignete Statistische Lerntheorie. Wir studieren lerntheoretische Garantien zur Absch{\"a}tzung der Vorhersagequalit{\"a}t auf ungesehenen Mustern. K{\"u}rzlich haben sich sogenannte Klassifikationstechniken mit großem Margin als ein praktisches Ergebnis dieser Theorie herausgestellt - insbesondere Boosting und Support-Vektor-Maschinen. Ein großer Margin impliziert eine hohe Vorhersagequalit{\"a}t der Entscheidungsregel. Deshalb wird analysiert, wie groß der Margin bei Boosting ist und ein verbesserter Algorithmus vorgeschlagen, der effizient Regeln mit maximalem Margin erzeugt. o Was ist der Zusammenhang von Boosting und Techniken der konvexen Optimierung? Um die Eigenschaften der entstehenden Klassifikations- oder Regressionsregeln zu analysieren, ist es sehr wichtig zu verstehen, ob und unter welchen Bedingungen iterative Algorithmen wie Boosting konvergieren. Wir zeigen, daß solche Algorithmen benutzt werden koennen, um sehr große Optimierungsprobleme mit Nebenbedingungen zu l{\"o}sen, deren L{\"o}sung sich gut charakterisieren laesst. Dazu werden Verbindungen zum Wissenschaftsgebiet der konvexen Optimierung aufgezeigt und ausgenutzt, um Konvergenzgarantien f{\"u}r eine große Familie von Boosting-{\"a}hnlichen Algorithmen zu geben. o Kann man Boosting robust gegen{\"u}ber Meßfehlern und Ausreissern in den Daten machen? Ein Problem bisheriger Boosting-Methoden ist die relativ hohe Sensitivit{\"a}t gegen{\"u}ber Messungenauigkeiten und Meßfehlern in der Trainingsdatenmenge. Um dieses Problem zu beheben, wird die sogenannte 'Soft-Margin' Idee, die beim Support-Vector Lernen schon benutzt wird, auf Boosting {\"u}bertragen. Das f{\"u}hrt zu theoretisch gut motivierten, regularisierten Algorithmen, die ein hohes Maß an Robustheit aufweisen. o Wie kann man die Anwendbarkeit von Boosting auf Regressionsprobleme erweitern? Boosting-Methoden wurden urspr{\"u}nglich f{\"u}r Klassifikationsprobleme entwickelt. Um die Anwendbarkeit auf Regressionsprobleme zu erweitern, werden die vorherigen Konvergenzresultate benutzt und neue Boosting-{\"a}hnliche Algorithmen zur Regression entwickelt. Wir zeigen, daß diese Algorithmen gute theoretische und praktische Eigenschaften haben. o Ist Boosting praktisch anwendbar? Die dargestellten theoretischen Ergebnisse werden begleitet von Simulationsergebnissen, entweder, um bestimmte Eigenschaften von Algorithmen zu illustrieren, oder um zu zeigen, daß sie in der Praxis tats{\"a}chlich gut funktionieren und direkt einsetzbar sind. Die praktische Relevanz der entwickelten Methoden wird in der Analyse chaotischer Zeitreihen und durch industrielle Anwendungen wie ein Stromverbrauch-{\"U}berwachungssystem und bei der Entwicklung neuer Medikamente illustriert.},
language = {en}
}
@phdthesis{Dawoud2013,
author = {Dawoud, Wesam},
title = {Scalability and performance management of internet applications in the cloud},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-68187},
school = {Universit{\"a}t Potsdam},
year = {2013},
abstract = {Cloud computing is a model for enabling on-demand access to a shared pool of computing resources. With virtually limitless on-demand resources, a cloud environment enables the hosted Internet application to quickly cope when there is an increase in the workload. However, the overhead of provisioning resources exposes the Internet application to periods of under-provisioning and performance degradation. Moreover, the performance interference, due to the consolidation in the cloud environment, complicates the performance management of the Internet applications. In this dissertation, we propose two approaches to mitigate the impact of the resources provisioning overhead. The first approach employs control theory to scale resources vertically and cope fast with workload. This approach assumes that the provider has knowledge and control over the platform running in the virtual machines (VMs), which limits it to Platform as a Service (PaaS) and Software as a Service (SaaS) providers. The second approach is a customer-side one that deals with the horizontal scalability in an Infrastructure as a Service (IaaS) model. It addresses the trade-off problem between cost and performance with a multi-goal optimization solution. This approach finds the scale thresholds that achieve the highest performance with the lowest increase in the cost. Moreover, the second approach employs a proposed time series forecasting algorithm to scale the application proactively and avoid under-utilization periods. Furthermore, to mitigate the interference impact on the Internet application performance, we developed a system which finds and eliminates the VMs suffering from performance interference. The developed system is a light-weight solution which does not imply provider involvement. To evaluate our approaches and the designed algorithms at large-scale level, we developed a simulator called (ScaleSim). In the simulator, we implemented scalability components acting as the scalability components of Amazon EC2. The current scalability implementation in Amazon EC2 is used as a reference point for evaluating the improvement in the scalable application performance. ScaleSim is fed with realistic models of the RUBiS benchmark extracted from the real environment. The workload is generated from the access logs of the 1998 world cup website. The results show that optimizing the scalability thresholds and adopting proactive scalability can mitigate 88\% of the resources provisioning overhead impact with only a 9\% increase in the cost.},
language = {en}
}
@article{Goettel2013,
author = {G{\"o}ttel, Timo},
title = {Schnupperveranstaltungen Informatik in der Hochschullandschaft},
series = {Commentarii informaticae didacticae : (CID)},
journal = {Commentarii informaticae didacticae : (CID)},
number = {5},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-64860},
pages = {45 -- 55},
year = {2013},
abstract = {Die vorliegende Arbeit er{\"o}rtert die Frage, wie Nachwuchs f{\"u}r das Informatikstudium nachhaltig gesichert werden kann. Dazu werden Befragungen unter Sch{\"u}lerinnen und Sch{\"u}lern (13-16 Jahre), sowie aktuelle Informatik-Schnupperangebote f{\"u}r Sch{\"u}lerinnen und Sch{\"u}ler an deutschsprachigen Hochschulen vorgestellt und untersucht. Diese Gegen{\"u}berstellung zeigt deutlich, dass die Angebote nur bedingt eine breite Zielgruppe ansprechen und dass weitere Formate und Inhalte notwendig sind, um Sch{\"u}lerinnen und Sch{\"u}ler fr{\"u}hzeitig und in voller Breite zu erreichen und f{\"u}r das Informatikstudium zu begeistern. Daraus wird abgeleitet, dass Missverst{\"a}ndnisse und Probleme mit der Informatik im Schulkontext aufgegriffen werden m{\"u}ssen. Das vorgestellte Programm Schulbotschafter Informatik stellt einen m{\"o}glichen Weg dar, um dies zu erreichen und {\"u}bliche Schnupperangebote zu erg{\"a}nzen.},
language = {de}
}
@phdthesis{AlAreqi2017,
author = {Al-Areqi, Samih Taha Mohammed},
title = {Semantics-based automatic geospatial service composition},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-402616},
school = {Universit{\"a}t Potsdam},
pages = {xvi, 163},
year = {2017},
abstract = {Although it has become common practice to build applications based on the reuse of existing components or services, technical complexity and semantic challenges constitute barriers to ensuring a successful and wide reuse of components and services. In the geospatial application domain, the barriers are self-evident due to heterogeneous geographic data, a lack of interoperability and complex analysis processes. Constructing workflows manually and discovering proper services and data that match user intents and preferences is difficult and time-consuming especially for users who are not trained in software development. Furthermore, considering the multi-objective nature of environmental modeling for the assessment of climate change impacts and the various types of geospatial data (e.g., formats, scales, and georeferencing systems) increases the complexity challenges. Automatic service composition approaches that provide semantics-based assistance in the process of workflow design have proven to be a solution to overcome these challenges and have become a frequent demand especially by end users who are not IT experts. In this light, the major contributions of this thesis are: (i) Simplification of service reuse and workflow design of applications for climate impact analysis by following the eXtreme Model-Driven Development (XMDD) paradigm. (ii) Design of a semantic domain model for climate impact analysis applications that comprises specifically designed services, ontologies that provide domain-specific vocabulary for referring to types and services, and the input/output annotation of the services using the terms defined in the ontologies. (iii) Application of a constraint-driven method for the automatic composition of workflows for analyzing the impacts of sea-level rise. The application scenario demonstrates the impact of domain modeling decisions on the results and the performance of the synthesis algorithm.},
language = {en}
}