@article{DelgrandeSchaubTompitsetal.2013, author = {Delgrande, James and Schaub, Torsten H. and Tompits, Hans and Woltran, Stefan}, title = {A model-theoretic approach to belief change in answer set programming}, series = {ACM transactions on computational logic}, volume = {14}, journal = {ACM transactions on computational logic}, number = {2}, publisher = {Association for Computing Machinery}, address = {New York}, issn = {1529-3785}, doi = {10.1145/2480759.2480766}, pages = {46}, year = {2013}, abstract = {We address the problem of belief change in (nonmonotonic) logic programming under answer set semantics. Our formal techniques are analogous to those of distance-based belief revision in propositional logic. In particular, we build upon the model theory of logic programs furnished by SE interpretations, where an SE interpretation is a model of a logic program in the same way that a classical interpretation is a model of a propositional formula. Hence we extend techniques from the area of belief revision based on distance between models to belief change in logic programs. We first consider belief revision: for logic programs P and Q, the goal is to determine a program R that corresponds to the revision of P by Q, denoted P * Q. We investigate several operators, including (logic program) expansion and two revision operators based on the distance between the SE models of logic programs. It proves to be the case that expansion is an interesting operator in its own right, unlike in classical belief revision where it is relatively uninteresting. Expansion and revision are shown to satisfy a suite of interesting properties; in particular, our revision operators satisfy all or nearly all of the AGM postulates for revision. We next consider approaches for merging a set of logic programs, P-1,...,P-n. Again, our formal techniques are based on notions of relative distance between the SE models of the logic programs. Two approaches are examined. The first informally selects for each program P-i those models of P-i that vary the least from models of the other programs. The second approach informally selects those models of a program P-0 that are closest to the models of programs P-1,...,P-n. In this case, P-0 can be thought of as a set of database integrity constraints. We examine these operators with regards to how they satisfy relevant postulate sets. Last, we present encodings for computing the revision as well as the merging of logic programs within the same logic programming framework. This gives rise to a direct implementation of our approach in terms of off-the-shelf answer set solvers. These encodings also reflect the fact that our change operators do not increase the complexity of the base formalism.}, 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} } @article{Doerge2013, author = {D{\"o}rge, Christina}, title = {Entwicklung eines methodologischen Verfahrens zur Ermittlung von informatischen Kompetenzen}, 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-64906}, pages = {85 -- 90}, year = {2013}, abstract = {Der traditionelle Weg in der Informatik besteht darin, Kompetenzen entweder normativ durch eine Expertengruppe festzulegen oder als Ableitungsergebnis eines Bildungsstandards aus einem externen Feld. Dieser Artikel stellt einen neuartigen und alternativen Ansatz vor, der sich der Methodik der Qualitativen Inhaltsanalyse (QI) bedient. Das Ziel war die Ableitung von informatischen Schl{\"u}sselkompetenzen anhand bereits etablierter und erprobter didaktischer Ans{\"a}tze der Informatikdidaktik. Dazu wurde zun{\"a}chst aus einer Reihe von Informatikdidaktikb{\"u}chern eine Liste mit m{\"o}glichen Kandidaten f{\"u}r Kompetenzen generiert. Diese Liste wurde als QI-Kategoriensystem verwendet, mit der sechs verschiedene didaktische Ans{\"a}tze analysiert wurden. Ein abschließender Verfeinerungsschritt erfolgte durch die {\"U}berpr{\"u}fung, welche der gefundenen Kompetenzen in allen vier Kernbereichen der Informatik (theoretische, technische, praktische und angewandte Informatik) Anwendung finden. Diese Methode wurde f{\"u}r die informatische Schulausbildung exemplarisch entwickelt und umgesetzt, ist aber ebenfalls ein geeignetes Vorgehen f{\"u}r die Identifizierung von Schl{\"u}sselkompetenzen in anderen Gebieten, wie z. B. in der informatischen Hochschulausbildung, und soll deshalb hier kurz vorgestellt werden.}, 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} } @book{KnobelsdorfKreitz2013, author = {Knobelsdorf, Maria and Kreitz, Christoph}, title = {Ein konstruktivistischer Lehransatz f{\"u}r die Einf{\"u}hrungsveranstaltung der Theoretische Informatik}, isbn = {978-3-86956-220-9}, year = {2013}, language = {de} } @phdthesis{Boehm2013, author = {B{\"o}hm, Christoph}, title = {Enriching the Web of Data with topics and links}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-68624}, school = {Universit{\"a}t Potsdam}, year = {2013}, abstract = {This thesis presents novel ideas and research findings for the Web of Data - a global data space spanning many so-called Linked Open Data sources. Linked Open Data adheres to a set of simple principles to allow easy access and reuse for data published on the Web. Linked Open Data is by now an established concept and many (mostly academic) publishers adopted the principles building a powerful web of structured knowledge available to everybody. However, so far, Linked Open Data does not yet play a significant role among common web technologies that currently facilitate a high-standard Web experience. In this work, we thoroughly discuss the state-of-the-art for Linked Open Data and highlight several shortcomings - some of them we tackle in the main part of this work. First, we propose a novel type of data source meta-information, namely the topics of a dataset. This information could be published with dataset descriptions and support a variety of use cases, such as data source exploration and selection. For the topic retrieval, we present an approach coined Annotated Pattern Percolation (APP), which we evaluate with respect to topics extracted from Wikipedia portals. Second, we contribute to entity linking research by presenting an optimization model for joint entity linking, showing its hardness, and proposing three heuristics implemented in the LINked Data Alignment (LINDA) system. Our first solution can exploit multi-core machines, whereas the second and third approach are designed to run in a distributed shared-nothing environment. We discuss and evaluate the properties of our approaches leading to recommendations which algorithm to use in a specific scenario. The distributed algorithms are among the first of their kind, i.e., approaches for joint entity linking in a distributed fashion. Also, we illustrate that we can tackle the entity linking problem on the very large scale with data comprising more than 100 millions of entity representations from very many sources. Finally, we approach a sub-problem of entity linking, namely the alignment of concepts. We again target a method that looks at the data in its entirety and does not neglect existing relations. Also, this concept alignment method shall execute very fast to serve as a preprocessing for further computations. Our approach, called Holistic Concept Matching (HCM), achieves the required speed through grouping the input by comparing so-called knowledge representations. Within the groups, we perform complex similarity computations, relation conclusions, and detect semantic contradictions. The quality of our result is again evaluated on a large and heterogeneous dataset from the real Web. In summary, this work contributes a set of techniques for enhancing the current state of the Web of Data. All approaches have been tested on large and heterogeneous real-world input.}, language = {en} } @misc{Frank2013, type = {Master Thesis}, author = {Frank, Mario}, title = {TEMPLAR : efficient determination of relevant axioms in big formula sets for theorem proving}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-72112}, school = {Universit{\"a}t Potsdam}, year = {2013}, abstract = {This document presents a formula selection system for classical first order theorem proving based on the relevance of formulae for the proof of a conjecture. It is based on unifiability of predicates and is also able to use a linguistic approach for the selection. The scope of the technique is the reduction of the set of formulae and the increase of the amount of provable conjectures in a given time. Since the technique generates a subset of the formula set, it can be used as a preprocessor for automated theorem proving. The document contains the conception, implementation and evaluation of both selection concepts. While the one concept generates a search graph over the negation normal forms or Skolem normal forms of the given formulae, the linguistic concept analyses the formulae and determines frequencies of lexemes and uses a tf-idf weighting algorithm to determine the relevance of the formulae. Though the concept is built for first order logic, it is not limited to it. The concept can be used for higher order and modal logik, too, with minimal adoptions. The system was also evaluated at the world championship of automated theorem provers (CADE ATP Systems Competition, CASC-24) in combination with the leanCoP theorem prover and the evaluation of the results of the CASC and the benchmarks with the problems of the CASC of the year 2012 (CASC-J6) show that the concept of the system has positive impact to the performance of automated theorem provers. Also, the benchmarks with two different theorem provers which use different calculi have shown that the selection is independent from the calculus. Moreover, the concept of TEMPLAR has shown to be competitive to some extent with the concept of SinE and even helped one of the theorem provers to solve problems that were not (or slower) solved with SinE selection in the CASC. Finally, the evaluation implies that the combination of the unification based and linguistic selection yields more improved results though no optimisation was done for the problems.}, 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} } @article{KnobelsdorfKreitz2013, author = {Knobelsdorf, Maria and Kreitz, Christoph}, title = {Ein konstruktivistischer Lehransatz f{\"u}r die Einf{\"u}hrungsveranstaltung der Theoretischen 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-64845}, pages = {21 -- 32}, year = {2013}, abstract = {Ausgehend von einem sozial-konstruktivistischen Verst{\"a}ndnis von Lernprozessen und unter der besonderen Ber{\"u}cksichtigung der durch die Bologna-Studienreform angeregten Kompetenzorientierung, haben wir in den letzten Jahren einen hochschuldidaktischen Ansatz f{\"u}r die Einf{\"u}hrungsveranstaltung im Bereich der Theoretischen Informatik an der Universit{\"a}t Potsdam entwickelt und praktisch erprobt. Nach zahlreichen Experimenten und mit einer Durchfallquote von zuletzt 6\% im Wintersemester 2011/2012 haben wir den Eindruck, dass der Ansatz den Studierenden jene Lernumgebung und -anregung bietet, die ihnen hilft, die entsprechenden Fachkompetenzen in der Veranstaltung zu entwickeln. In diesem Artikel stellen wir unseren Ansatz vor und skizzieren abschlie{\"y}end, wie wir diesen im n{\"a}chsten Wintersemester empirisch evaluieren werden.}, language = {de} } @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} } @article{GoetzBrinda2013, author = {G{\"o}tz, Christian and Brinda, Torsten}, title = {Sind soziale Netzwerke geeignet, um darin f{\"u}r Informatikstudieng{\"a}nge zu werben?}, 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-65017}, pages = {137 -- 142}, year = {2013}, abstract = {Durch den bundesweiten R{\"u}ckgang der Sch{\"u}lerzahlen und einer steigenden Zahl von Bildungsangeboten geraten Universit{\"a}ten und Hochschulen in den n{\"a}chsten Jahren weiter in eine Wettbewerbssituation, weshalb sie effektive Marketingmaßnahmen entwickeln m{\"u}ssen, um Sch{\"u}lerinnen und Sch{\"u}ler m{\"o}glichst fr{\"u}hzeitig f{\"u}r das jeweilige Angebot (z. B. Informatik- und informatiknahe Studieng{\"a}nge) zu interessieren. Ein Medium, {\"u}ber das sich potenziell sehr viele Jugendliche erreichen lassen, sind dabei soziale Netzwerke. Diese Arbeit pr{\"a}sentiert Ergebnisse einer Studie unter Informatikstudienanf{\"a}ngerinnen und -anf{\"a}ngern zum Nutzungsverhalten sozialer Netzwerke und zieht Schlussfolgerungen zu deren Eignung als Werbe- und Informationskanal f{\"u}r die Zielgruppe der Informatikinteressierten.}, language = {de} } @article{ApelBergBergneretal.2013, author = {Apel, Rebecca and Berg, Tobias and Bergner, Nadine and Chatti, Mhamed Amine and Holz, Jan and Leicht-Scholten, Carmen and Schroeder, Ulrike}, title = {Ein vierstufiges F{\"o}rderkonzept f{\"u}r die Studieneingangsphase in 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-65025}, pages = {143 -- 148}, year = {2013}, abstract = {Es wird ein vierstufiges F{\"o}rderkonzept f{\"u}r die Studieneingangsphase im Fach Informatik beschrieben, das derzeit im Rahmen des Projekts IGaDtools4MINT an der RWTH Aachen auf der Basis einer Literaturanalyse und eines daraus abgeleiteten Indikatorenkatalogs entwickelt wird.}, language = {de} } @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} } @article{DelikostidisEngelRetsiosetal.2013, author = {Delikostidis, Ioannis and Engel, Juri and Retsios, Bas and van Elzakker, Corne P. J. M. and Kraak, Menno-Jan and D{\"o}llner, J{\"u}rgen Roland Friedrich}, title = {Increasing the usability of pedestrian navigation interfaces by means of landmark visibility analysis}, series = {The journal of navigation}, volume = {66}, journal = {The journal of navigation}, number = {4}, publisher = {Cambridge Univ. Press}, address = {New York}, issn = {0373-4633}, doi = {10.1017/S0373463313000209}, pages = {523 -- 537}, year = {2013}, abstract = {Communicating location-specific information to pedestrians is a challenging task which can be aided by user-friendly digital technologies. In this paper, landmark visibility analysis, as a means for developing more usable pedestrian navigation systems, is discussed. Using an algorithmic framework for image-based 3D analysis, this method integrates a 3D city model with identified landmarks and produces raster visibility layers for each one. This output enables an Android phone prototype application to indicate the visibility of landmarks from the user's actual position. Tested in the field, the method achieves sufficient accuracy for the context of use and improves navigation efficiency and effectiveness.}, language = {en} } @article{RichterKyprianidisDoellner2013, author = {Richter, Rico and Kyprianidis, Jan Eric and D{\"o}llner, J{\"u}rgen Roland Friedrich}, title = {Out-of-core GPU-based change detection in massive 3D point clouds}, series = {Transactions in GIS}, volume = {17}, journal = {Transactions in GIS}, number = {5}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {1361-1682}, doi = {10.1111/j.1467-9671.2012.01362.x}, pages = {724 -- 741}, year = {2013}, abstract = {If sites, cities, and landscapes are captured at different points in time using technology such as LiDAR, large collections of 3D point clouds result. Their efficient storage, processing, analysis, and presentation constitute a challenging task because of limited computation, memory, and time resources. In this work, we present an approach to detect changes in massive 3D point clouds based on an out-of-core spatial data structure that is designed to store data acquired at different points in time and to efficiently attribute 3D points with distance information. Based on this data structure, we present and evaluate different processing schemes optimized for performing the calculation on the CPU and GPU. In addition, we present a point-based rendering technique adapted for attributed 3D point clouds, to enable effective out-of-core real-time visualization of the computation results. Our approach enables conclusions to be drawn about temporal changes in large highly accurate 3D geodata sets of a captured area at reasonable preprocessing and rendering times. We evaluate our approach with two data sets from different points in time for the urban area of a city, describe its characteristics, and report on applications.}, language = {en} } @phdthesis{Kyprianidis2013, author = {Kyprianidis, Jan Eric}, title = {Structure adaptive stylization of images and video}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-64104}, school = {Universit{\"a}t Potsdam}, year = {2013}, abstract = {In the early days of computer graphics, research was mainly driven by the goal to create realistic synthetic imagery. By contrast, non-photorealistic computer graphics, established as its own branch of computer graphics in the early 1990s, is mainly motivated by concepts and principles found in traditional art forms, such as painting, illustration, and graphic design, and it investigates concepts and techniques that abstract from reality using expressive, stylized, or illustrative rendering techniques. This thesis focuses on the artistic stylization of two-dimensional content and presents several novel automatic techniques for the creation of simplified stylistic illustrations from color images, video, and 3D renderings. Primary innovation of these novel techniques is that they utilize the smooth structure tensor as a simple and efficient way to obtain information about the local structure of an image. More specifically, this thesis contributes to knowledge in this field in the following ways. First, a comprehensive review of the structure tensor is provided. In particular, different methods for integrating the minor eigenvector field of the smoothed structure tensor are developed, and the superiority of the smoothed structure tensor over the popular edge tangent flow is demonstrated. Second, separable implementations of the popular bilateral and difference of Gaussians filters that adapt to the local structure are presented. These filters avoid artifacts while being computationally highly efficient. Taken together, both provide an effective way to create a cartoon-style effect. Third, a generalization of the Kuwahara filter is presented that avoids artifacts by adapting the shape, scale, and orientation of the filter to the local structure. This causes directional image features to be better preserved and emphasized, resulting in overall sharper edges and a more feature-abiding painterly effect. In addition to the single-scale variant, a multi-scale variant is presented, which is capable of performing a highly aggressive abstraction. Fourth, a technique that builds upon the idea of combining flow-guided smoothing with shock filtering is presented, allowing for an aggressive exaggeration and an emphasis of directional image features. All presented techniques are suitable for temporally coherent per-frame filtering of video or dynamic 3D renderings, without requiring expensive extra processing, such as optical flow. Moreover, they can be efficiently implemented to process content in real-time on a GPU.}, language = {en} } @article{HilseLucke2013, author = {Hilse, Michael and Lucke, Ulrike}, title = {eLiS - E-Learning in Studienbereichen}, series = {E-Learning Symposium 2012 : Aktuelle Anwendungen, innovative Prozesse und neueste Ergebnisse aus der E-Learning-Praxis ; Potsdam, 17. November 2012}, journal = {E-Learning Symposium 2012 : Aktuelle Anwendungen, innovative Prozesse und neueste Ergebnisse aus der E-Learning-Praxis ; Potsdam, 17. November 2012}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, doi = {10.25932/publishup-44227}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-442275}, pages = {73 -- 75}, year = {2013}, abstract = {Deutsche Universit{\"a}ten erweitern ihre E-Learning-Angebote als Service f{\"u}r die Studierenden und Lehrenden. Diese sind je nach Fakult{\"a}t unterschiedlich ausgepr{\"a}gt. Dieser Artikel zeigt, wie durch technische Erweiterung der Infrastruktur, einer Anpassung der Organisationsstruktur und einer gezielten Inhaltsentwicklung eine durchg{\"a}ngige und personalisierbare Lehr- und Lernumgebung (Personal Learning Environment, PLE) geschaffen und damit die Akzeptanz bei den Lehrenden und Studierenden f{\"u}r E-Learning erh{\"o}ht werden kann. Aus der vorausgehenden, systematischen Anforderungsanalyse k{\"o}nnen Kennzahlen f{\"u}r die Qualit{\"a}tssicherung von E-Learning-Angeboten abgeleitet werden.}, language = {de} } @inproceedings{TavangarianSchroederIgeletal.2013, author = {Tavangarian, Djamshid and Schroeder, Ulrik and Igel, Christoph and Magenheim, Johannes and Kundisch, Dennis and Beutner, Marc and Herrmann, Philipp and Whittaker, Michael and Reinhardt, Wolfgang and Zoyke, Andrea and Elbeshausen, Stefanie and Griesbaum, Joachim and Koelle, Ralph and Kneiphoff, Anika Hanna and Mauch, Martina and H{\"u}bner, Sandra and Walter, Satjawan and Dittler, Ullrich and Baumann, Annette and Reeh, Lucas and Beuster, Liane and Elkina, Margarita and Fortenbacher, Albrecht and Kappe, Leonard and Merceron, Agathe and Pursian, Andreas and Schwarzrock, Sebastian and Wenzlaff, Boris and Hilse, Michael and Lucke, Ulrike}, title = {E-Learning Symposium 2012}, editor = {Lucke, Ulrike}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, doi = {10.25932/publishup-6162}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-62661}, pages = {77}, year = {2013}, abstract = {Dieser Tagungsband beinhaltet die auf dem E-Learning Symposium 2012 an der Universit{\"a}t Potsdam vorgestellten Beitr{\"a}ge zu aktuellen Anwendungen, innovativen Prozesse und neuesten Ergebnissen im Themenbereich E-Learning. Lehrende, E-Learning-Praktiker und -Entscheider tauschten ihr Wissen {\"u}ber etablierte und geplante Konzepte im Zusammenhang mit dem Student-Life-Cycle aus. Der Schwerpunkt lag hierbei auf der unmittelbaren Unterst{\"u}tzung von Lehr- und Lernprozessen, auf Pr{\"a}sentation, Aktivierung und Kooperation durch Verwendung von neuen und etablierten Technologien.}, language = {de} } @phdthesis{Yang2013, author = {Yang, Haojin}, title = {Automatic video indexing and retrieval using video ocr technology}, address = {Potsdam}, pages = {182 S.}, year = {2013}, 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} }