@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{ZscheygeWeicker2016,
author = {Zscheyge, Oliver and Weicker, Karsten},
title = {Werkzeugunterst{\"u}tzung bei der Vermittlung der Grundlagen wissenschaftlichen Schreibens},
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-opus4-94814},
pages = {57 -- 68},
year = {2016},
abstract = {Der Unterricht großer Studierendengruppen im wissenschaftlichen Schreiben birgt vielf{\"a}ltige organisatorische Herausforderungen und eine zeitintensive Betreuung durch die Dozenten. Diese Arbeit stellt ein Lehrkonzept mit Peer-Reviews vor, in dem das Feedback der Peers durch eine automatisierte Analyse erg{\"a}nzt wird. Die Software Confopy liefert metrik- und strukturbasierte Hinweise f{\"u}r die Verbesserung des wissenschaftlichen Schreibstils. Der Nutzen von Confopy wird an 47 studentischen Arbeiten in Draft- und Final-Version illustriert.},
language = {de}
}
@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{SteenWisniewskiBenzmueller2016,
author = {Steen, Alexander and Wisniewski, Max and Benzm{\"u}ller, Christoph},
title = {Einsatz von Theorembeweisern in der Lehre},
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-opus4-94853},
pages = {81 -- 92},
year = {2016},
abstract = {Dieser Beitrag diskutiert den Einsatz von interaktiven und automatischen Theorembeweisern in der universit{\"a}ren Lehre. Moderne Theorembeweiser scheinen geeignet zur Implementierung des dialogischen Lernens und als E-Assessment-Werkzeug in der Logikausbilding. Exemplarisch skizzieren wir ein innovaties Lehrprojekt zum Thema „Komputationale Metaphysik", in dem die zuvor genannten Werkzeuge eingesetzt werden.},
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}
}
@phdthesis{Waetzoldt2016,
author = {W{\"a}tzoldt, Sebastian},
title = {Modeling collaborations in adaptive systems of systems},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-97494},
school = {Universit{\"a}t Potsdam},
pages = {XII, 380},
year = {2016},
abstract = {Recently, due to an increasing demand on functionality and flexibility, beforehand isolated systems have become interconnected to gain powerful adaptive Systems of Systems (SoS) solutions with an overall robust, flexible and emergent behavior. The adaptive SoS comprises a variety of different system types ranging from small embedded to adaptive cyber-physical systems. On the one hand, each system is independent, follows a local strategy and optimizes its behavior to reach its goals. On the other hand, systems must cooperate with each other to enrich the overall functionality to jointly perform on the SoS level reaching global goals, which cannot be satisfied by one system alone. Due to difficulties of local and global behavior optimizations conflicts may arise between systems that have to be solved by the adaptive SoS. This thesis proposes a modeling language that facilitates the description of an adaptive SoS by considering the adaptation capabilities in form of feedback loops as first class entities. Moreover, this thesis adopts the Models@runtime approach to integrate the available knowledge in the systems as runtime models into the modeled adaptation logic. Furthermore, the modeling language focuses on the description of system interactions within the adaptive SoS to reason about individual system functionality and how it emerges via collaborations to an overall joint SoS behavior. Therefore, the modeling language approach enables the specification of local adaptive system behavior, the integration of knowledge in form of runtime models and the joint interactions via collaboration to place the available adaptive behavior in an overall layered, adaptive SoS architecture. Beside the modeling language, this thesis proposes analysis rules to investigate the modeled adaptive SoS, which enables the detection of architectural patterns as well as design flaws and pinpoints to possible system threats. Moreover, a simulation framework is presented, which allows the direct execution of the modeled SoS architecture. Therefore, the analysis rules and the simulation framework can be used to verify the interplay between systems as well as the modeled adaptation effects within the SoS. This thesis realizes the proposed concepts of the modeling language by mapping them to a state of the art standard from the automotive domain and thus, showing their applicability to actual systems. Finally, the modeling language approach is evaluated by remodeling up to date research scenarios from different domains, which demonstrates that the modeling language concepts are powerful enough to cope with a broad range of existing research problems.},
language = {en}
}
@unpublished{PrasseGrubenMachlikaetal.2016,
author = {Prasse, Paul and Gruben, Gerrit and Machlika, Lukas and Pevny, Tomas and Sofka, Michal and Scheffer, Tobias},
title = {Malware Detection by HTTPS Traffic Analysis},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-100942},
pages = {10},
year = {2016},
abstract = {In order to evade detection by network-traffic analysis, a growing proportion of malware uses the encrypted HTTPS protocol. We explore the problem of detecting malware on client computers based on HTTPS traffic analysis. In this setting, malware has to be detected based on the host IP address, ports, timestamp, and data volume information of TCP/IP packets that are sent and received by all the applications on the client. We develop a scalable protocol that allows us to collect network flows of known malicious and benign applications as training data and derive a malware-detection method based on a neural networks and sequence classification. We study the method's ability to detect known and new, unknown malware in a large-scale empirical study.},
language = {en}
}
@book{OPUS4-7534,
title = {Process design for natural scientists},
series = {Communications in computer and information science ; 500},
journal = {Communications in computer and information science ; 500},
editor = {Lambrecht, Anna-Lena and Margaria, Tizian},
publisher = {Springer},
address = {Wiesbaden},
isbn = {978-3-662-45005-5},
pages = {X, 251},
year = {2014},
abstract = {This book presents an agile and model-driven approach to manage scientific workflows. The approach is based on the Extreme Model Driven Design (XMDD) paradigm and aims at simplifying and automating the complex data analysis processes carried out by scientists in their day-to-day work. Besides documenting the impact the workflow modeling might have on the work of natural scientists, this book serves three major purposes: 1. It acts as a primer for practitioners who are interested to learn how to think in terms of services and workflows when facing domain-specific scientific processes. 2. It provides interesting material for readers already familiar with this kind of tools, because it introduces systematically both the technologies used in each case study and the basic concepts behind them. 3. As the addressed thematic field becomes increasingly relevant for lectures in both computer science and experimental sciences, it also provides helpful material for teachers that plan similar courses.},
language = {en}
}
@phdthesis{Wust2015,
author = {Wust, Johannes},
title = {Mixed workload managment for in-memory databases},
pages = {VIII, 167},
year = {2015},
language = {en}
}
@article{Teske2014,
author = {Teske, Daniel},
title = {Geocoder accuracy ranking},
series = {Process design for natural scientists: an agile model-driven approach},
journal = {Process design for natural scientists: an agile model-driven approach},
number = {500},
publisher = {Springer},
address = {Berlin},
isbn = {978-3-662-45005-5},
issn = {1865-0929},
pages = {161 -- 174},
year = {2014},
abstract = {Finding an address on a map is sometimes tricky: the chosen map application may be unfamiliar with the enclosed region. There are several geocoders on the market, they have different databases and algorithms to compute the query. Consequently, the geocoding results differ in their quality. Fortunately the geocoders provide a rich set of metadata. The workflow described in this paper compares this metadata with the aim to find out which geocoder is offering the best-fitting coordinate for a given address.},
language = {en}
}
@article{Sens2014,
author = {Sens, Henriette},
title = {Web-Based map generalization tools put to the test: a jABC workflow},
series = {Process Design for Natural Scientists: an agile model-driven approach},
journal = {Process Design for Natural Scientists: an agile model-driven approach},
number = {500},
publisher = {Springer},
address = {Berlin},
isbn = {978-3-662-45005-5},
issn = {1865-0929},
pages = {175 -- 185},
year = {2014},
abstract = {Geometric generalization is a fundamental concept in the digital mapping process. An increasing amount of spatial data is provided on the web as well as a range of tools to process it. This jABC workflow is used for the automatic testing of web-based generalization services like mapshaper.org by executing its functionality, overlaying both datasets before and after the transformation and displaying them visually in a .tif file. Mostly Web Services and command line tools are used to build an environment where ESRI shapefiles can be uploaded, processed through a chosen generalization service and finally visualized in Irfanview.},
language = {en}
}
@article{Noack2014,
author = {Noack, Franziska},
title = {CREADED: Colored-Relief application for digital elevation data},
series = {Process design for natural scientists: an agile model-driven approach},
journal = {Process design for natural scientists: an agile model-driven approach},
number = {500},
publisher = {Springer},
address = {Berlin},
isbn = {978-3-662-45005-5},
issn = {1865-0929},
pages = {186 -- 199},
year = {2014},
abstract = {In the geoinformatics field, remote sensing data is often used for analyzing the characteristics of the current investigation area. This includes DEMs, which are simple raster grids containing grey scales representing the respective elevation values. The project CREADED that is presented in this paper aims at making these monochrome raster images more significant and more intuitively interpretable. For this purpose, an executable interactive model for creating a colored and relief-shaded Digital Elevation Model (DEM) has been designed using the jABC framework. The process is based on standard jABC-SIBs and SIBs that provide specific GIS functions, which are available as Web services, command line tools and scripts.},
language = {en}
}
@article{Respondek2014,
author = {Respondek, Tobias},
title = {A workflow for computing potential areas for wind turbines},
series = {Process design for natural scientists: an agile model-driven approach},
journal = {Process design for natural scientists: an agile model-driven approach},
number = {500},
publisher = {Springer},
address = {Berlin},
isbn = {978-3-662-45005-5},
pages = {200 -- 215},
year = {2014},
abstract = {This paper describes the implementation of a workflow model for service-oriented computing of potential areas for wind turbines in jABC. By implementing a re-executable model the manual effort of a multi-criteria site analysis can be reduced. The aim is to determine the shift of typical geoprocessing tools of geographic information systems (GIS) from the desktop to the web. The analysis is based on a vector data set and mainly uses web services of the "Center for Spatial Information Science and Systems" (CSISS). This paper discusses effort, benefits and problems associated with the use of the web services.},
language = {en}
}
@article{Scheele2014,
author = {Scheele, Lasse},
title = {Location analysis for placing artificial reefs},
series = {Process design for natural scientists: an agile model-driven approach},
journal = {Process design for natural scientists: an agile model-driven approach},
number = {500},
publisher = {Springer},
address = {Berlin},
isbn = {978-3-662-45005-5},
issn = {1865-0929},
pages = {216 -- 228},
year = {2014},
abstract = {Location analyses are among the most common tasks while working with spatial data and geographic information systems. Automating the most frequently used procedures is therefore an important aspect of improving their usability. In this context, this project aims to design and implement a workflow, providing some basic tools for a location analysis. For the implementation with jABC, the workflow was applied to the problem of finding a suitable location for placing an artificial reef. For this analysis three parameters (bathymetry, slope and grain size of the ground material) were taken into account, processed, and visualized with the The Generic Mapping Tools (GMT), which were integrated into the workflow as jETI-SIBs. The implemented workflow thereby showed that the approach to combine jABC with GMT resulted in an user-centric yet user-friendly tool with high-quality cartographic outputs.},
language = {en}
}
@article{Kind2014,
author = {Kind, Josephine},
title = {Creation of topographic maps},
series = {Process design for natural scientists: an agile model-driven approach},
journal = {Process design for natural scientists: an agile model-driven approach},
number = {500},
publisher = {Springer},
address = {Berlin},
isbn = {978-3-662-45005-5},
pages = {229 -- 238},
year = {2014},
abstract = {Location analyses are among the most common tasks while working with spatial data and geographic information systems. Automating the most frequently used procedures is therefore an important aspect of improving their usability. In this context, this project aims to design and implement a workflow, providing some basic tools for a location analysis. For the implementation with jABC, the workflow was applied to the problem of finding a suitable location for placing an artificial reef. For this analysis three parameters (bathymetry, slope and grain size of the ground material) were taken into account, processed, and visualized with the The Generic Mapping Tools (GMT), which were integrated into the workflow as jETI-SIBs. The implemented workflow thereby showed that the approach to combine jABC with GMT resulted in an user-centric yet user-friendly tool with high-quality cartographic outputs.},
language = {en}
}
@article{Holler2014,
author = {Holler, Robin},
title = {GraffDok - a graffiti documentation application},
series = {Process design for natural scientists: an agile model-driven approach},
journal = {Process design for natural scientists: an agile model-driven approach},
number = {500},
publisher = {Springer},
address = {Berlin},
isbn = {978-3-662-45005-5},
issn = {1865-0929},
pages = {239 -- 251},
year = {2014},
abstract = {GraffDok is an application helping to maintain an overview over sprayed images somewhere in a city. At the time of writing it aims at vandalism rather than at beautiful photographic graffiti in an underpass. Looking at hundreds of tags and scribbles on monuments, house walls, etc. it would be interesting to not only record them in writing but even make them accessible electronically, including images. GraffDok's workflow is simple and only requires an EXIF-GPS-tagged photograph of a graffito. It automatically determines its location by using reverse geocoding with the given GPS-coordinates and the Gisgraphy WebService. While asking the user for some more meta data, GraffDok analyses the image in parallel with this and tries to detect fore- and background - before extracting the drawing lines and make them stand alone. The command line based tool ImageMagick is used here as well as for accessing EXIF data. Any meta data is written to csv-files, which will stay easily accessible and can be integrated in TeX-files as well. The latter ones are converted to PDF at the end of the workflow, containing a table about all graffiti and a summary for each - including the generated characteristic graffiti pattern image.},
language = {en}
}
@article{Reso2014,
author = {Reso, Judith},
title = {Protein Classification Workflow},
series = {Process Design for Natural Scientists: an agile model-driven approach},
journal = {Process Design for Natural Scientists: an agile model-driven approach},
number = {500},
editor = {Lambrecht, Anna-Lena and Margaria, Tiziana},
publisher = {Springer Verlag},
address = {Berlin},
isbn = {978-3-662-45005-5},
issn = {1865-0929},
pages = {65 -- 72},
year = {2014},
abstract = {The protein classification workflow described in this report enables users to get information about a novel protein sequence automatically. The information is derived by different bioinformatic analysis tools which calculate or predict features of a protein sequence. Also, databases are used to compare the novel sequence with known proteins.},
language = {en}
}
@article{Schulze2014,
author = {Schulze, Gunnar},
title = {Workflow for rapid metagenome analysis},
series = {Process design for natural scientists: an agile model-driven approach},
journal = {Process design for natural scientists: an agile model-driven approach},
number = {500},
publisher = {Springer},
address = {Berlin},
isbn = {978-3-662-45005-5},
issn = {1865-0929},
pages = {88 -- 100},
year = {2014},
abstract = {Analyses of metagenomes in life sciences present new opportunities as well as challenges to the scientific community and call for advanced computational methods and workflows. The large amount of data collected from samples via next-generation sequencing (NGS) technologies render manual approaches to sequence comparison and annotation unsuitable. Rather, fast and efficient computational pipelines are needed to provide comprehensive statistics and summaries and enable the researcher to choose appropriate tools for more specific analyses. The workflow presented here builds upon previous pipelines designed for automated clustering and annotation of raw sequence reads obtained from next-generation sequencing technologies such as 454 and Illumina. Employing specialized algorithms, the sequence reads are processed at three different levels. First, raw reads are clustered at high similarity cutoff to yield clusters which can be exported as multifasta files for further analyses. Independently, open reading frames (ORFs) are predicted from raw reads and clustered at two strictness levels to yield sets of non-redundant sequences and ORF families. Furthermore, single ORFs are annotated by performing searches against the Pfam database},
language = {en}
}
@article{Vierheller2014,
author = {Vierheller, Janine},
title = {Exploratory Data Analysis},
series = {Process Design for Natural Scientists: an agile model-driven approach},
journal = {Process Design for Natural Scientists: an agile model-driven approach},
number = {500},
editor = {Lambrecht, Anna-Lena and Margaria, Tiziana},
publisher = {Axel Springer Verlag},
address = {Berlin},
isbn = {978-3-662-45005-5},
issn = {1865-0929},
pages = {110 -- 126},
year = {2014},
abstract = {In bioinformatics the term exploratory data analysis refers to different methods to get an overview of large biological data sets. Hence, it helps to create a framework for further analysis and hypothesis testing. The workflow facilitates this first important step of the data analysis created by high-throughput technologies. The results are different plots showing the structure of the measurements. The goal of the workflow is the automatization of the exploratory data analysis, but also the flexibility should be guaranteed. The basic tool is the free software R.},
language = {en}
}
@article{Schuett2014,
author = {Sch{\"u}tt, Christine},
title = {Identification of differentially expressed genes},
series = {Process design for natural scientists: an agile model-driven approach},
journal = {Process design for natural scientists: an agile model-driven approach},
number = {500},
publisher = {Springer},
address = {Berlin},
isbn = {978-3-662-45005-5},
issn = {1865-0929},
pages = {127 -- 139},
year = {2014},
abstract = {With the jABC it is possible to realize workflows for numerous questions in different fields. The goal of this project was to create a workflow for the identification of differentially expressed genes. This is of special interest in biology, for it gives the opportunity to get a better insight in cellular changes due to exogenous stress, diseases and so on. With the knowledge that can be derived from the differentially expressed genes in diseased tissues, it becomes possible to find new targets for treatment.},
language = {en}
}
@article{Kuntzsch2014,
author = {Kuntzsch, Christian},
title = {Visualization of data transfer paths},
series = {Process design for natural scientists: an agile model-driven approach},
journal = {Process design for natural scientists: an agile model-driven approach},
number = {500},
publisher = {Springer},
address = {Berlin},
isbn = {978-3-662-45005-5},
issn = {1865-0929},
pages = {140 -- 148},
year = {2014},
abstract = {A workflow for visualizing server connections using the Google Maps API was built in the jABC. It makes use of three basic services: An XML-based IP address geolocation web service, a command line tool and the Static Maps API. The result of the workflow is an URL leading to an image file of a map, showing server connections between a client and a target host.},
language = {en}
}
@article{Hibbe2014,
author = {Hibbe, Marcel},
title = {Spotlocator - Guess Where the Photo Was Taken!},
series = {Process Design for Natural Scientists: an agile model-driven approach},
journal = {Process Design for Natural Scientists: an agile model-driven approach},
number = {500},
editor = {Lambrecht, Anna-Lena and Margaria, Tiziana},
publisher = {Springer Verlag},
address = {Berlin},
isbn = {978-3-662-45005-5},
issn = {1865-0929},
pages = {149 -- 160},
year = {2014},
abstract = {Spotlocator is a game wherein people have to guess the spots of where photos were taken. The photos of a defined area for each game are from panoramio.com. They are published at http://spotlocator. drupalgardens.com with an ID. Everyone can guess the photo spots by sending a special tweet via Twitter that contains the hashtag \#spotlocator, the guessed coordinates and the ID of the photo. An evaluation is published for all tweets. The players are informed about the distance to the real photo spots and the positions are shown on a map.},
language = {en}
}
@article{Blaese2014,
author = {Blaese, Leif},
title = {Data mining for unidentified protein squences},
series = {Process design for natural scientists: an agile model-driven approach},
journal = {Process design for natural scientists: an agile model-driven approach},
number = {500},
publisher = {Springer},
address = {Berlin},
isbn = {978-3-662-45005-5},
issn = {1865-0929},
pages = {73 -- 87},
year = {2014},
abstract = {Through the use of next generation sequencing (NGS) technology, a lot of newly sequenced organisms are now available. Annotating those genes is one of the most challenging tasks in sequence biology. Here, we present an automated workflow to find homologue proteins, annotate sequences according to function and create a three-dimensional model.},
language = {en}
}
@article{Lis2014,
author = {Lis, Monika},
title = {Constructing a Phylogenetic Tree},
series = {Process Design for Natural Scientists: an agile model-driven approach},
journal = {Process Design for Natural Scientists: an agile model-driven approach},
number = {500},
editor = {Lambrecht, Anna-Lena and Margaria, Tiziana},
publisher = {Springer Verlag},
address = {Berlin},
isbn = {978-3-662-45005-5},
issn = {1865-0929},
pages = {101 -- 109},
year = {2014},
abstract = {In this project I constructed a workflow that takes a DNA sequence as input and provides a phylogenetic tree, consisting of the input sequence and other sequences which were found during a database search. In this phylogenetic tree the sequences are arranged depending on similarities. In bioinformatics, constructing phylogenetic trees is often used to explore the evolutionary relationships of genes or organisms and to understand the mechanisms of evolution itself.},
language = {en}
}
@book{PlattnerZeier2012,
author = {Plattner, Hasso and Zeier, Alexander},
title = {In-Memory Data Management},
publisher = {Springer},
address = {Wiesbaden},
isbn = {978-3-8349-4378-1},
publisher = {Universit{\"a}t Potsdam},
pages = {200},
year = {2012},
abstract = {Nach 50 Jahren erfolgreicher Entwicklunghat die Business-IT einen neuenWendepunkt erreicht. Hier zeigen die Autoren erstmalig, wieIn-Memory Computing dieUnternehmensprozesse k{\"u}nftig ver{\"a}ndern wird. Bisher wurden Unternehmensdaten aus Performance-Gr{\"u}nden auf verschiedene Datenbanken verteilt: Analytische Datenresidieren in Data Warehouses und werden regelm{\"a}ßig mithilfe transaktionaler Systeme synchronisiert. Diese Aufspaltung macht flexibles Echtzeit-Reporting aktueller Daten unm{\"o}glich. Doch dank leistungsf{\"a}higerMulti-Core-CPUs, großer Hauptspeicher, Cloud Computing und immerbesserer mobiler Endger{\"a}te lassen die Unternehmen dieses restriktive Modell zunehmend hinter sich. Die Autoren stellen Techniken vor, die eine analytische und transaktionale Verarbeitung in Echtzeit erlauben und so dem Gesch{\"a}ftsleben neue Wege bahnen.},
language = {de}
}
@phdthesis{Heise2014,
author = {Heise, Arvid},
title = {Data cleansing and integration operators for a parallel data analytics platform},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-77100},
school = {Universit{\"a}t Potsdam},
pages = {ii, 179},
year = {2014},
abstract = {The data quality of real-world datasets need to be constantly monitored and maintained to allow organizations and individuals to reliably use their data. Especially, data integration projects suffer from poor initial data quality and as a consequence consume more effort and money. Commercial products and research prototypes for data cleansing and integration help users to improve the quality of individual and combined datasets. They can be divided into either standalone systems or database management system (DBMS) extensions. On the one hand, standalone systems do not interact well with DBMS and require time-consuming data imports and exports. On the other hand, DBMS extensions are often limited by the underlying system and do not cover the full set of data cleansing and integration tasks. We overcome both limitations by implementing a concise set of five data cleansing and integration operators on the parallel data analytics platform Stratosphere. We define the semantics of the operators, present their parallel implementation, and devise optimization techniques for individual operators and combinations thereof. Users specify declarative queries in our query language METEOR with our new operators to improve the data quality of individual datasets or integrate them to larger datasets. By integrating the data cleansing operators into the higher level language layer of Stratosphere, users can easily combine cleansing operators with operators from other domains, such as information extraction, to complex data flows. Through a generic description of the operators, the Stratosphere optimizer reorders operators even from different domains to find better query plans. As a case study, we reimplemented a part of the large Open Government Data integration project GovWILD with our new operators and show that our queries run significantly faster than the original GovWILD queries, which rely on relational operators. Evaluation reveals that our operators exhibit good scalability on up to 100 cores, so that even larger inputs can be efficiently processed by scaling out to more machines. Finally, our scripts are considerably shorter than the original GovWILD scripts, which results in better maintainability of the scripts.},
language = {en}
}
@article{FroitzheimBergnerSchroeder2015,
author = {Froitzheim, Manuel and Bergner, Nadine and Schroeder, Ulrik},
title = {Android-Workshop zur Vertiefung der Kenntnisse bez{\"u}glich Datenstrukturen und Programmierung in der Studieneingangsphase},
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},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-80247},
pages = {11 -- 26},
year = {2015},
abstract = {Die Studieneingangsphase stellt f{\"u}r Studierende eine Schl{\"u}sselphase des terti{\"a}ren Ausbildungsabschnitts dar. Fachwissenschaftliches Wissen wird praxisfern vermittelt und die Studierenden k{\"o}nnen die Zusammenh{\"a}nge zwischen den Themenfeldern der verschiedenen Vorlesungen nicht erkennen. Zur Verbesserung der Situation wurde ein Workshop entwickelt, der die Verbindung der Programmierung und der Datenstrukturen vertieft. Dabei wird das Spiel Go-Moku1 als Android-App von den Studierenden selbst{\"a}ndig entwickelt. Die Kombination aus Software (Java, Android-SDK) und Hardware (Tablet-Computer) f{\"u}r ein kleines realistisches Softwareprojekt stellt f{\"u}r die Studierenden eine neue Erfahrung dar.},
language = {de}
}
@misc{Voland2014,
type = {Master Thesis},
author = {Voland, Patrick},
title = {Webbasierte Visualisierung von Extended Floating Car Data (XFCD)},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-96751},
school = {Universit{\"a}t Potsdam},
pages = {VIII, 176},
year = {2014},
abstract = {Moderne Kraftfahrzeuge verf{\"u}gen {\"u}ber eine Vielzahl an Sensoren, welche f{\"u}r einen reibungslosen technischen Betrieb ben{\"o}tigt werden. Hierzu z{\"a}hlen neben fahrzeugspezifischen Sensoren (wie z.B. Motordrehzahl und Fahrzeuggeschwindigkeit) auch umweltspezifische Sensoren (wie z.B. Luftdruck und Umgebungstemperatur). Durch die zunehmende technische Vernetzung wird es m{\"o}glich, diese Daten der Kraftfahrzeugelektronik aus dem Fahrzeug heraus f{\"u}r die verschiedensten Zwecke zu verwenden. Die vorliegende Arbeit soll einen Beitrag dazu leisten, diese neue Art an massenhaften Daten im Sinne des Konzepts der „Extended Floating Car Data" (XFCD) als Geoinformationen nutzbar zu machen und diese f{\"u}r raumzeitliche Visualisierungen (zur visuellen Analyse) anwenden zu k{\"o}nnen. In diesem Zusammenhang wird speziell die Perspektive des Umwelt- und Verkehrsmonitoring betrachtet, wobei die Anforderungen und Potentiale mit Hilfe von Experteninterviews untersucht werden. Es stellt sich die Frage, welche Daten durch die Kraftfahrzeugelektronik geliefert und wie diese m{\"o}glichst automatisiert erfasst, verarbeitet, visualisiert und {\"o}ffentlich bereitgestellt werden k{\"o}nnen. Neben theoretischen und technischen Grundlagen zur Datenerfassung und -nutzung liegt der Fokus auf den Methoden der kartographischen Visualisierung. Dabei soll der Frage nachgegangenen werden, ob eine technische Implementierung ausschließlich unter Verwendung von Open Source Software m{\"o}glich ist. Das Ziel der Arbeit bildet ein zweigliedriger Ansatz, welcher zum einen die Visualisierung f{\"u}r ein exemplarisch gew{\"a}hltes Anwendungsszenario und zum anderen die prototypische Implementierung von der Datenerfassung im Fahrzeug unter Verwendung der gesetzlich vorgeschriebenen „On Board Diagnose"-Schnittstelle und einem Smartphone-gest{\"u}tzten Ablauf bis zur webbasierten Visualisierung umfasst.},
language = {de}
}
@book{KunzeWeske2016,
author = {Kunze, Matthias and Weske, Mathias},
title = {Behavioural Models},
publisher = {Springer},
address = {Cham},
isbn = {978-3-319-44958-6},
publisher = {Universit{\"a}t Potsdam},
pages = {279},
year = {2016},
abstract = {This textbook introduces the basis for modelling and analysing discrete dynamic systems, such as computer programmes, soft- and hardware systems, and business processes. The underlying concepts are introduced and concrete modelling techniques are described, such as finite automata, state machines, and Petri nets. The concepts are related to concrete application scenarios, among which business processes play a prominent role. The book consists of three parts, the first of which addresses the foundations of behavioural modelling. After a general introduction to modelling, it introduces transition systems as a basic formalism for representing the behaviour of discrete dynamic systems. This section also discusses causality, a fundamental concept for modelling and reasoning about behaviour. In turn, Part II forms the heart of the book and is devoted to models of behaviour. It details both sequential and concurrent systems and introduces finite automata, state machines and several different types of Petri nets. One chapter is especially devoted to business process models, workflow patterns and BPMN, the industry standard for modelling business processes. Lastly, Part III investigates how the behaviour of systems can be analysed. To this end, it introduces readers to the concept of state spaces. Further chapters cover the comparison of behaviour and the formal analysis and verification of behavioural models. The book was written for students of computer science and software engineering, as well as for programmers and system analysts interested in the behaviour of the systems they work on. It takes readers on a journey from the fundamentals of behavioural modelling to advanced techniques for modelling and analysing sequential and concurrent systems, and thus provides them a deep understanding of the concepts and techniques introduced and how they can be applied to concrete application scenarios.},
language = {en}
}
@phdthesis{Neuhaus2017,
author = {Neuhaus, Christian},
title = {Sicherheitsmechanismen f{\"u}r dienstbasierte Softwaresysteme},
school = {Universit{\"a}t Potsdam},
pages = {183},
year = {2017},
language = {de}
}
@phdthesis{Kilic2016,
author = {Kilic, Mukayil},
title = {Vernetztes Pr{\"u}fen von elektronischen Komponenten {\"u}ber das Internet},
school = {Universit{\"a}t Potsdam},
pages = {104, XVI},
year = {2016},
language = {de}
}
@book{SmirnovReijersNugterenetal.2010,
author = {Smirnov, Sergey and Reijers, Hajo A. and Nugteren, Thijs and Weske, Mathias},
title = {Business process model abstraction : theory and practice},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-054-0},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-41782},
publisher = {Universit{\"a}t Potsdam},
pages = {17},
year = {2010},
abstract = {Business process management aims at capturing, understanding, and improving work in organizations. The central artifacts are process models, which serve different purposes. Detailed process models are used to analyze concrete working procedures, while high-level models show, for instance, handovers between departments. To provide different views on process models, business process model abstraction has emerged. While several approaches have been proposed, a number of abstraction use case that are both relevant for industry and scientifically challenging are yet to be addressed. In this paper we systematically develop, classify, and consolidate different use cases for business process model abstraction. The reported work is based on a study with BPM users in the health insurance sector and validated with a BPM consultancy company and a large BPM vendor. The identified fifteen abstraction use cases reflect the industry demand. The related work on business process model abstraction is evaluated against the use cases, which leads to a research agenda.},
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{Scholz2006,
author = {Scholz, Matthias},
title = {Approaches to analyse and interpret biological profile data},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-7839},
school = {Universit{\"a}t Potsdam},
year = {2006},
abstract = {Advances in biotechnologies rapidly increase the number of molecules of a cell which can be observed simultaneously. This includes expression levels of thousands or ten-thousands of genes as well as concentration levels of metabolites or proteins. Such Profile data, observed at different times or at different experimental conditions (e.g., heat or dry stress), show how the biological experiment is reflected on the molecular level. This information is helpful to understand the molecular behaviour and to identify molecules or combination of molecules that characterise specific biological condition (e.g., disease). This work shows the potentials of component extraction algorithms to identify the major factors which influenced the observed data. This can be the expected experimental factors such as the time or temperature as well as unexpected factors such as technical artefacts or even unknown biological behaviour. Extracting components means to reduce the very high-dimensional data to a small set of new variables termed components. Each component is a combination of all original variables. The classical approach for that purpose is the principal component analysis (PCA). It is shown that, in contrast to PCA which maximises the variance only, modern approaches such as independent component analysis (ICA) are more suitable for analysing molecular data. The condition of independence between components of ICA fits more naturally our assumption of individual (independent) factors which influence the data. This higher potential of ICA is demonstrated by a crossing experiment of the model plant Arabidopsis thaliana (Thale Cress). The experimental factors could be well identified and, in addition, ICA could even detect a technical artefact. However, in continuously observations such as in time experiments, the data show, in general, a nonlinear distribution. To analyse such nonlinear data, a nonlinear extension of PCA is used. This nonlinear PCA (NLPCA) is based on a neural network algorithm. The algorithm is adapted to be applicable to incomplete molecular data sets. Thus, it provides also the ability to estimate the missing data. The potential of nonlinear PCA to identify nonlinear factors is demonstrated by a cold stress experiment of Arabidopsis thaliana. The results of component analysis can be used to build a molecular network model. Since it includes functional dependencies it is termed functional network. Applied to the cold stress data, it is shown that functional networks are appropriate to visualise biological processes and thereby reveals molecular dynamics.},
subject = {Bioinformatik},
language = {en}
}
@article{Arnold2007,
author = {Arnold, Holger},
title = {A linearized DPLL calculus with learning},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-15421},
year = {2007},
abstract = {This paper describes the proof calculus LD for clausal propositional logic, which is a linearized form of the well-known DPLL calculus extended by clause learning. It is motivated by the demand to model how current SAT solvers built on clause learning are working, while abstracting from decision heuristics and implementation details. The calculus is proved sound and terminating. Further, it is shown that both the original DPLL calculus and the conflict-directed backtracking calculus with clause learning, as it is implemented in many current SAT solvers, are complete and proof-confluent instances of the LD calculus.},
language = {en}
}
@book{OPUS4-1390,
title = {Wir gehen multimedial. Kommt Ihr mit?},
editor = {Laabs, Hans-Joachim},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-939469-59-9},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-15034},
publisher = {Universit{\"a}t Potsdam},
pages = {158},
year = {2007},
abstract = {"Wir gehen multimedial. Kommt ihr mit?" war Aufruf und Leitmotiv der MultimeDies 2007. Es kamen sehr viele mit, vor allem Lehrende und Lernende der Universit{\"a}t Potsdam, aber auch Firmen. Diese Veranstaltung setzt eine Tradition fort, die im Bem{\"u}hen steht {\"u}ber zukunftsweisende Technologien und Projekte, {\"u}ber Angebote und praktikable L{\"o}sungen an der Universit{\"a}t zu informieren. Die Vortr{\"a}ge wurden in kurzen Beitr{\"a}gen zusammengestellt. Sie gliedern sich in zwei Gruppen, zum einen der Bereitstellung, zum anderen der Nutzung von Multimedia.},
language = {de}
}
@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}
}
@misc{Trapp2007,
type = {Master Thesis},
author = {Trapp, Matthias},
title = {Analysis and exploration of virtual 3D city models using 3D information lenses},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-13930},
school = {Universit{\"a}t Potsdam},
year = {2007},
abstract = {This thesis addresses real-time rendering techniques for 3D information lenses based on the focus \& context metaphor. It analyzes, conceives, implements, and reviews its applicability to objects and structures of virtual 3D city models. In contrast to digital terrain models, the application of focus \& context visualization to virtual 3D city models is barely researched. However, the purposeful visualization of contextual data of is extreme importance for the interactive exploration and analysis of this field. Programmable hardware enables the implementation of new lens techniques, that allow the augmentation of the perceptive and cognitive quality of the visualization compared to classical perspective projections. A set of 3D information lenses is integrated into a 3D scene-graph system: • Occlusion lenses modify the appearance of virtual 3D city model objects to resolve their occlusion and consequently facilitate the navigation. • Best-view lenses display city model objects in a priority-based manner and mediate their meta information. Thus, they support exploration and navigation of virtual 3D city models. • Color and deformation lenses modify the appearance and geometry of 3D city models to facilitate their perception. The presented techniques for 3D information lenses and their application to virtual 3D city models clarify their potential for interactive visualization and form a base for further development.},
language = {en}
}
@book{OPUS4-1401,
title = {Barrierefreie Internetauftritte},
editor = {Buhse, J{\"o}rg and Scheske, Michael},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-937786-39-1},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-15203},
publisher = {Universit{\"a}t Potsdam},
pages = {49},
year = {2005},
abstract = {Vorwort: Immer mehr B{\"u}rgerinnen und B{\"u}rger nutzen die vielf{\"a}ltigen M{\"o}glichkeiten der neuen elektronischen Medien. Dabei erfreut sich insbesondere das Internet einer zunehmenden Beliebtheit und steigender Nutzerzahlen. Damit verbunden steigt auch die Zahl der Webauftritte und Internetangebote. Doch einem Teil der Internet-Community bleibt der Zugang zu vielen dieser Angebote versagt. Dies sind vor allem Menschen mit Behinderungen, aber auch Nutzer, deren verwendete Hard- und Software zur Darstellung der angebotenen Inhalte seitens der Anbieter nicht unterst{\"u}tzt werden. Im Wesentlichen geht es um zwei Arten von „Barrieren" bei der Nutzung von Informationstechnik: Zum einen um technische Barrieren bei der Darstellung und zum anderen um kognitive Barrieren bez{\"u}glich des Verstehens der dargestellten Inhalte. Die Schaffung barrierefreier Informationstechnik ist deshalb ein wichtiges Kriterium bei der Ausgestaltung {\"o}ffentlicher Internetauftritte und -angebote. Hierzu gibt es eine Reihe rechtlicher Regelungen, unter anderem im Behindertengleichstellungsgesetz (BGG) oder der Barrierefreien Informationstechnikverordnung (BITV), deren Umsetzung in den einzelnen Bundesl{\"a}ndern sehr unterschiedlich geregelt ist. Auch wenn die Kommunen in manchen Bundesl{\"a}ndern - so auch in Brandenburg - von den gesetzlichen Regelungen ausgenommen sind, ist eine Realisierung barrierefreier Internetauftritte von Kommunen w{\"u}nschenswert, um allen B{\"u}rgern einen gleichwertigen Zugang zu kommunalen Interangeboten zu erm{\"o}glichen. Um vor allem die kommunale Praxis bei der Erstellung barrierefreier Internetangebote zu unterst{\"u}tzen, hat das Kommunalwissenschaftliche Institut (KWI) der Universit{\"a}t Potsdam im Dezember 2004 einen Workshop unter dem Titel „Barrierefreie Internetauftritte - Aspekte der Umsetzung des Behindertengleichstellungsgesetzes in elektronischen Medien" veranstaltet. Ziel war es, umfassende Informationen zum Thema „Barrierefreiheit" zu vermitteln sowie Hinweise und L{\"o}sungsm{\"o}glichkeiten f{\"u}r die Realisierung barrierefreier Internetauftritte zu geben. Im Mittelpunkt standen dabei folgende Fragen: Was k{\"o}nnen und sollen kommunale Internetauftritte leisten? Was bedeutet Barrierefreiheit bez{\"u}glich „elektronischer Medien" und welche Auswirkungen ergeben sich daraus f{\"u}r die Gestaltung von Internetauftritten? Welche gesetzlichen Regelungen gibt es und welche Geltungsbereiche haben sie im Einzelnen? Welche technischen L{\"o}sungen kommen f{\"u}r die Erstellung barrierefreier Internetseiten in Betracht? Das vorliegende Arbeitsheft ist Teil der Dokumentation der Ergebnisse des Workshops. Die einzelnen Beitr{\"a}ge fassen die Vortr{\"a}ge der Referenten zusammen.},
language = {de}
}
@misc{Piesker2007,
type = {Master Thesis},
author = {Piesker, Bj{\"o}rn},
title = {Constraint-basierte Generierung realit{\"a}tsnaher Eisenbahnnetze},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-15325},
school = {Universit{\"a}t Potsdam},
year = {2007},
abstract = {Diese Arbeit befasst sich mit der Entwicklung einer Applikation, welche Infrastrukturdaten {\"u}ber Eisenbahnnetze generiert. Dabei bildet die Erzeugung der topologischen Informationen den Schwerpunkt dieser Arbeit. Der Anwender charakterisiert hierf{\"u}r vorab das gew{\"u}nschte Eisenbahnnetz, wobei die geforderten Eigenschaften die Randbedingungen darstellen, die bei der Synthese zu beachten sind. Zur Einhaltung dieser Bedingungen wird die Constraint-Programmierung eingesetzt, welche durch ihr spezielles Programmierparadigma konsistente L{\"o}sungen effizient erzeugt. Dies wird u.a. durch die Nachnutzung so genannter globaler Constraints erreicht. Aus diesem Grund wird insbesondere auf den Einsatz der Constraint-Programmierung bei der Modellierung und Implementierung der Applikation eingegangen.},
language = {de}
}
@misc{Kirchner2007,
type = {Master Thesis},
author = {Kirchner, Peter},
title = {Verteilte Autorisierung innerhalb von Single Sign-On-Umgebungen : Analyse, Architektur und Implementation eines Frameworks f{\"u}r verteilte Autorisierung in einer ADFS-Umgebung},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-22289},
school = {Universit{\"a}t Potsdam},
year = {2007},
abstract = {Aktuelle Softwaresysteme erlauben die verteilte Authentifizierung von Benutzern {\"u}ber Ver-zeichnisdienste, die sowohl im Intranet als auch im Extranet liegen und die {\"u}ber Dom{\"a}nen-grenzen hinweg die Kooperation mit Partnern erm{\"o}glichen. Der n{\"a}chste Schritt ist es nun, die Autorisierung ebenfalls aus der lokalen Anwendung auszulagern und diese extern durchzu-f{\"u}hren - vorzugsweise unter dem Einfluss der Authentifizierungspartner. Basierend auf der Analyse des State-of-the-Art wird in dieser Arbeit ein Framework vorges-tellt, das die verteilte Autorisierung von ADFS (Active Directory Federation Services) authenti-fizierten Benutzern auf Basis ihrer Gruppen oder ihrer pers{\"o}nlichen Identit{\"a}t erm{\"o}glicht. Es wird eine prototypische Implementation mit Diensten entwickelt, die f{\"u}r authentifizierte Be-nutzer Autorisierungsanfragen extern delegieren, sowie ein Dienst, der diese Autorisierungs-anfragen verarbeitet. Zus{\"a}tzlich zeigt die Arbeit eine Integration dieses Autorisierungs-Frameworks in das .NET Framework, um die praxistaugliche Verwendbarkeit in einer aktuel-len Entwicklungsumgebung zu demonstrieren. Abschließend wird ein Ausblick auf weitere Fragestellungen und Folgearbeiten gegeben.},
language = {de}
}
@phdthesis{Blum2010,
author = {Blum, Niklas},
title = {Formalization of a converged internet and telecommunications service environment},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-51146},
school = {Universit{\"a}t Potsdam},
year = {2010},
abstract = {The programmable network envisioned in the 1990s within standardization and research for the Intelligent Network is currently coming into reality using IPbased Next Generation Networks (NGN) and applying Service-Oriented Architecture (SOA) principles for service creation, execution, and hosting. SOA is the foundation for both next-generation telecommunications and middleware architectures, which are rapidly converging on top of commodity transport services. Services such as triple/quadruple play, multimedia messaging, and presence are enabled by the emerging service-oriented IPMultimedia Subsystem (IMS), and allow telecommunications service providers to maintain, if not improve, their position in the marketplace. SOA becomes the de facto standard in next-generation middleware systems as the system model of choice to interconnect service consumers and providers within and between enterprises. We leverage previous research activities in overlay networking technologies along with recent advances in network abstraction, service exposure, and service creation to develop a paradigm for a service environment providing converged Internet and Telecommunications services that we call Service Broker. Such a Service Broker provides mechanisms to combine and mediate between different service paradigms from the two domains Internet/WWW and telecommunications. Furthermore, it enables the composition of services across these domains and is capable of defining and applying temporal constraints during creation and execution time. By adding network-awareness into the service fabric, such a Service Broker may also act as a next generation network-to-service element allowing the composition of crossdomain and cross-layer network and service resources. The contribution of this research is threefold: first, we analyze and classify principles and technologies from Information Technologies (IT) and telecommunications to identify and discuss issues allowing cross-domain composition in a converging service layer. Second, we discuss service composition methods allowing the creation of converged services on an abstract level; in particular, we present a formalized method for model-checking of such compositions. Finally, we propose a Service Broker architecture converging Internet and Telecom services. This environment enables cross-domain feature interaction in services through formalized obligation policies acting as constraints during service discovery, creation, and execution time.},
language = {en}
}
@phdthesis{Brauer2010,
author = {Brauer, Falk},
title = {Extraktion und Identifikation von Entit{\"a}ten in Textdaten im Umfeld der Enterprise Search},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-51409},
school = {Universit{\"a}t Potsdam},
year = {2010},
abstract = {Die automatische Informationsextraktion (IE) aus unstrukturierten Texten erm{\"o}glicht v{\"o}llig neue Wege, auf relevante Informationen zuzugreifen und deren Inhalte zu analysieren, die weit {\"u}ber bisherige Verfahren zur Stichwort-basierten Dokumentsuche hinausgehen. Die Entwicklung von Programmen zur Extraktion von maschinenlesbaren Daten aus Texten erfordert jedoch nach wie vor die Entwicklung von dom{\"a}nenspezifischen Extraktionsprogrammen. Insbesondere im Bereich der Enterprise Search (der Informationssuche im Unternehmensumfeld), in dem eine große Menge von heterogenen Dokumenttypen existiert, ist es oft notwendig ad-hoc Programm-module zur Extraktion von gesch{\"a}ftsrelevanten Entit{\"a}ten zu entwickeln, die mit generischen Modulen in monolithischen IE-Systemen kombiniert werden. Dieser Umstand ist insbesondere kritisch, da potentiell f{\"u}r jeden einzelnen Anwendungsfall ein von Grund auf neues IE-System entwickelt werden muss. Die vorliegende Dissertation untersucht die effiziente Entwicklung und Ausf{\"u}hrung von IE-Systemen im Kontext der Enterprise Search und effektive Methoden zur Ausnutzung bekannter strukturierter Daten im Unternehmenskontext f{\"u}r die Extraktion und Identifikation von gesch{\"a}ftsrelevanten Entit{\"a}ten in Doku-menten. Grundlage der Arbeit ist eine neuartige Plattform zur Komposition von IE-Systemen auf Basis der Beschreibung des Datenflusses zwischen generischen und anwendungsspezifischen IE-Modulen. Die Plattform unterst{\"u}tzt insbesondere die Entwicklung und Wiederverwendung von generischen IE-Modulen und zeichnet sich durch eine h{\"o}here Flexibilit{\"a}t und Ausdrucksm{\"a}chtigkeit im Vergleich zu vorherigen Methoden aus. Ein in der Dissertation entwickeltes Verfahren zur Dokumentverarbeitung interpretiert den Daten-austausch zwischen IE-Modulen als Datenstr{\"o}me und erm{\"o}glicht damit eine weitgehende Parallelisierung von einzelnen Modulen. Die autonome Ausf{\"u}hrung der Module f{\"u}hrt zu einer wesentlichen Beschleu-nigung der Verarbeitung von Einzeldokumenten und verbesserten Antwortzeiten, z. B. f{\"u}r Extraktions-dienste. Bisherige Ans{\"a}tze untersuchen lediglich die Steigerung des durchschnittlichen Dokumenten-durchsatzes durch verteilte Ausf{\"u}hrung von Instanzen eines IE-Systems. Die Informationsextraktion im Kontext der Enterprise Search unterscheidet sich z. B. von der Extraktion aus dem World Wide Web dadurch, dass in der Regel strukturierte Referenzdaten z. B. in Form von Unternehmensdatenbanken oder Terminologien zur Verf{\"u}gung stehen, die oft auch die Beziehungen von Entit{\"a}ten beschreiben. Entit{\"a}ten im Unternehmensumfeld haben weiterhin bestimmte Charakteristiken: Eine Klasse von relevanten Entit{\"a}ten folgt bestimmten Bildungsvorschriften, die nicht immer bekannt sind, auf die aber mit Hilfe von bekannten Beispielentit{\"a}ten geschlossen werden kann, so dass unbekannte Entit{\"a}ten extrahiert werden k{\"o}nnen. Die Bezeichner der anderen Klasse von Entit{\"a}ten haben eher umschreibenden Charakter. Die korrespondierenden Umschreibungen in Texten k{\"o}nnen variieren, wodurch eine Identifikation derartiger Entit{\"a}ten oft erschwert wird. Zur effizienteren Entwicklung von IE-Systemen wird in der Dissertation ein Verfahren untersucht, das alleine anhand von Beispielentit{\"a}ten effektive Regul{\"a}re Ausdr{\"u}cke zur Extraktion von unbekannten Entit{\"a}ten erlernt und damit den manuellen Aufwand in derartigen Anwendungsf{\"a}llen minimiert. Verschiedene Generalisierungs- und Spezialisierungsheuristiken erkennen Muster auf verschiedenen Abstraktionsebenen und schaffen dadurch einen Ausgleich zwischen Genauigkeit und Vollst{\"a}ndigkeit bei der Extraktion. Bekannte Regellernverfahren im Bereich der Informationsextraktion unterst{\"u}tzen die beschriebenen Problemstellungen nicht, sondern ben{\"o}tigen einen (annotierten) Dokumentenkorpus. Eine Methode zur Identifikation von Entit{\"a}ten, die durch Graph-strukturierte Referenzdaten vordefiniert sind, wird als dritter Schwerpunkt untersucht. Es werden Verfahren konzipiert, welche {\"u}ber einen exakten Zeichenkettenvergleich zwischen Text und Referenzdatensatz hinausgehen und Teil{\"u}bereinstimmungen und Beziehungen zwischen Entit{\"a}ten zur Identifikation und Disambiguierung heranziehen. Das in der Arbeit vorgestellte Verfahren ist bisherigen Ans{\"a}tzen hinsichtlich der Genauigkeit und Vollst{\"a}ndigkeit bei der Identifikation {\"u}berlegen.},
language = {de}
}
@phdthesis{Lorey2014,
author = {Lorey, Johannes},
title = {What's in a query : analyzing, predicting, and managing linked data access},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-72312},
school = {Universit{\"a}t Potsdam},
year = {2014},
abstract = {The term Linked Data refers to connected information sources comprising structured data about a wide range of topics and for a multitude of applications. In recent years, the conceptional and technical foundations of Linked Data have been formalized and refined. To this end, well-known technologies have been established, such as the Resource Description Framework (RDF) as a Linked Data model or the SPARQL Protocol and RDF Query Language (SPARQL) for retrieving this information. Whereas most research has been conducted in the area of generating and publishing Linked Data, this thesis presents novel approaches for improved management. In particular, we illustrate new methods for analyzing and processing SPARQL queries. Here, we present two algorithms suitable for identifying structural relationships between these queries. Both algorithms are applied to a large number of real-world requests to evaluate the performance of the approaches and the quality of their results. Based on this, we introduce different strategies enabling optimized access of Linked Data sources. We demonstrate how the presented approach facilitates effective utilization of SPARQL endpoints by prefetching results relevant for multiple subsequent requests. Furthermore, we contribute a set of metrics for determining technical characteristics of such knowledge bases. To this end, we devise practical heuristics and validate them through thorough analysis of real-world data sources. We discuss the findings and evaluate their impact on utilizing the endpoints. Moreover, we detail the adoption of a scalable infrastructure for improving Linked Data discovery and consumption. As we outline in an exemplary use case, this platform is eligible both for processing and provisioning the corresponding information.},
language = {en}
}
@phdthesis{Steinert2014,
author = {Steinert, Bastian},
title = {Built-in recovery support for explorative programming},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-71305},
school = {Universit{\"a}t Potsdam},
year = {2014},
abstract = {This work introduces concepts and corresponding tool support to enable a complementary approach in dealing with recovery. Programmers need to recover a development state, or a part thereof, when previously made changes reveal undesired implications. However, when the need arises suddenly and unexpectedly, recovery often involves expensive and tedious work. To avoid tedious work, literature recommends keeping away from unexpected recovery demands by following a structured and disciplined approach, which consists of the application of various best practices including working only on one thing at a time, performing small steps, as well as making proper use of versioning and testing tools. However, the attempt to avoid unexpected recovery is both time-consuming and error-prone. On the one hand, it requires disproportionate effort to minimize the risk of unexpected situations. On the other hand, applying recommended practices selectively, which saves time, can hardly avoid recovery. In addition, the constant need for foresight and self-control has unfavorable implications. It is exhaustive and impedes creative problem solving. This work proposes to make recovery fast and easy and introduces corresponding support called CoExist. Such dedicated support turns situations of unanticipated recovery from tedious experiences into pleasant ones. It makes recovery fast and easy to accomplish, even if explicit commits are unavailable or tests have been ignored for some time. When mistakes and unexpected insights are no longer associated with tedious corrective actions, programmers are encouraged to change source code as a means to reason about it, as opposed to making changes only after structuring and evaluating them mentally. This work further reports on an implementation of the proposed tool support in the Squeak/Smalltalk development environment. The development of the tools has been accompanied by regular performance and usability tests. In addition, this work investigates whether the proposed tools affect programmers' performance. In a controlled lab study, 22 participants improved the design of two different applications. Using a repeated measurement setup, the study examined the effect of providing CoExist on programming performance. The result of analyzing 88 hours of programming suggests that built-in recovery support as provided with CoExist positively has a positive effect on programming performance in explorative programming tasks.},
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}
}
@book{KrauseGiese2012,
author = {Krause, Christian and Giese, Holger},
title = {Quantitative modeling and analysis of service-oriented real-time systems using interval probabilistic timed automata},
publisher = {Universit{\"a}tsverlah Potsdam},
address = {Potsdam},
isbn = {978-3-86956-171-4},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-57845},
publisher = {Universit{\"a}t Potsdam},
pages = {45},
year = {2012},
abstract = {One of the key challenges in service-oriented systems engineering is the prediction and assurance of non-functional properties, such as the reliability and the availability of composite interorganizational services. Such systems are often characterized by a variety of inherent uncertainties, which must be addressed in the modeling and the analysis approach. The different relevant types of uncertainties can be categorized into (1) epistemic uncertainties due to incomplete knowledge and (2) randomization as explicitly used in protocols or as a result of physical processes. In this report, we study a probabilistic timed model which allows us to quantitatively reason about nonfunctional properties for a restricted class of service-oriented real-time systems using formal methods. To properly motivate the choice for the used approach, we devise a requirements catalogue for the modeling and the analysis of probabilistic real-time systems with uncertainties and provide evidence that the uncertainties of type (1) and (2) in the targeted systems have a major impact on the used models and require distinguished analysis approaches. The formal model we use in this report are Interval Probabilistic Timed Automata (IPTA). Based on the outlined requirements, we give evidence that this model provides both enough expressiveness for a realistic and modular specifiation of the targeted class of systems, and suitable formal methods for analyzing properties, such as safety and reliability properties in a quantitative manner. As technical means for the quantitative analysis, we build on probabilistic model checking, specifically on probabilistic time-bounded reachability analysis and computation of expected reachability rewards and costs. To carry out the quantitative analysis using probabilistic model checking, we developed an extension of the Prism tool for modeling and analyzing IPTA. Our extension of Prism introduces a means for modeling probabilistic uncertainty in the form of probability intervals, as required for IPTA. For analyzing IPTA, our Prism extension moreover adds support for probabilistic reachability checking and computation of expected rewards and costs. We discuss the performance of our extended version of Prism and compare the interval-based IPTA approach to models with fixed probabilities.},
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{Bordihn2011,
author = {Bordihn, Henning},
title = {Contributions to the syntactical analysis beyond context-freeness},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-59719},
school = {Universit{\"a}t Potsdam},
year = {2011},
abstract = {Parsability approaches of several grammar formalisms generating also non-context-free languages are explored. Chomsky grammars, Lindenmayer systems, grammars with controlled derivations, and grammar systems are treated. Formal properties of these mechanisms are investigated, when they are used as language acceptors. Furthermore, cooperating distributed grammar systems are restricted so that efficient deterministic parsing without backtracking becomes possible. For this class of grammar systems, the parsing algorithm is presented and the feature of leftmost derivations is investigated in detail.},
language = {en}
}
@book{GieseHildebrandtNeumannetal.2012,
author = {Giese, Holger and Hildebrandt, Stephan and Neumann, Stefan and W{\"a}tzoldt, Sebastian},
title = {Industrial case study on the integration of SysML and AUTOSAR with triple graph grammars},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-191-2},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-60184},
publisher = {Universit{\"a}t Potsdam},
pages = {vi, 51},
year = {2012},
abstract = {During the overall development of complex engineering systems different modeling notations are employed. For example, in the domain of automotive systems system engineering models are employed quite early to capture the requirements and basic structuring of the entire system, while software engineering models are used later on to describe the concrete software architecture. Each model helps in addressing the specific design issue with appropriate notations and at a suitable level of abstraction. However, when we step forward from system design to the software design, the engineers have to ensure that all decisions captured in the system design model are correctly transferred to the software engineering model. Even worse, when changes occur later on in either model, today the consistency has to be reestablished in a cumbersome manual step. In this report, we present in an extended version of [Holger Giese, Stefan Neumann, and Stephan Hildebrandt. Model Synchronization at Work: Keeping SysML and AUTOSAR Models Consistent. In Gregor Engels, Claus Lewerentz, Wilhelm Sch{\"a}fer, Andy Sch{\"u}rr, and B. Westfechtel, editors, Graph Transformations and Model Driven Enginering - Essays Dedicated to Manfred Nagl on the Occasion of his 65th Birthday, volume 5765 of Lecture Notes in Computer Science, pages 555-579. Springer Berlin / Heidelberg, 2010.] how model synchronization and consistency rules can be applied to automate this task and ensure that the different models are kept consistent. We also introduce a general approach for model synchronization. Besides synchronization, the approach consists of tool adapters as well as consistency rules covering the overlap between the synchronized parts of a model and the rest. We present the model synchronization algorithm based on triple graph grammars in detail and further exemplify the general approach by means of a model synchronization solution between system engineering models in SysML and software engineering models in AUTOSAR which has been developed for an industrial partner. In the appendix as extension to [19] the meta-models and all TGG rules for the SysML to AUTOSAR model synchronization are documented.},
language = {en}
}
@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}
}
@book{HauptMarrHirschfeld2011,
author = {Haupt, Michael and Marr, Stefan and Hirschfeld, Robert},
title = {CSOM/PL : a virtual machine product line},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-134-9},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-52332},
publisher = {Universit{\"a}t Potsdam},
pages = {26},
year = {2011},
abstract = {CSOM/PL is a software product line (SPL) derived from applying multi-dimensional separation of concerns (MDSOC) techniques to the domain of high-level language virtual machine (VM) implementations. For CSOM/PL, we modularised CSOM, a Smalltalk VM implemented in C, using VMADL (virtual machine architecture description language). Several features of the original CSOM were encapsulated in VMADL modules and composed in various combinations. In an evaluation of our approach, we show that applying MDSOC and SPL principles to a domain as complex as that of VMs is not only feasible but beneficial, as it improves understandability, maintainability, and configurability of VM implementations without harming performance.},
language = {en}
}
@book{NeumannGiese2013,
author = {Neumann, Stefan and Giese, Holger},
title = {Scalable compatibility for embedded real-time components via language progressive timed automata},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-226-1},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-63853},
publisher = {Universit{\"a}t Potsdam},
pages = {vi, 67},
year = {2013},
abstract = {The proper composition of independently developed components of an embedded real- time system is complicated due to the fact that besides the functional behavior also the non-functional properties and in particular the timing have to be compatible. Nowadays related compatibility problems have to be addressed in a cumbersome integration and configuration phase at the end of the development process, that in the worst case may fail. Therefore, a number of formal approaches have been developed, which try to guide the upfront decomposition of the embedded real-time system into components such that integration problems related to timing properties can be excluded and that suitable configurations can be found. However, the proposed solutions require a number of strong assumptions that can be hardly fulfilled or the required analysis does not scale well. In this paper, we present an approach based on timed automata that can provide the required guarantees for the later integration without strong assumptions, which are difficult to match in practice. The approach provides a modular reasoning scheme that permits to establish the required guarantees for the integration employing only local checks, which therefore also scales. It is also possible to determine potential configuration settings by means of timed game synthesis.},
language = {de}
}
@phdthesis{Sawade2012,
author = {Sawade, Christoph},
title = {Active evaluation of predictive models},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-255-1},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-65583},
school = {Universit{\"a}t Potsdam},
pages = {ix, 157},
year = {2012},
abstract = {The field of machine learning studies algorithms that infer predictive models from data. Predictive models are applicable for many practical tasks such as spam filtering, face and handwritten digit recognition, and personalized product recommendation. In general, they are used to predict a target label for a given data instance. In order to make an informed decision about the deployment of a predictive model, it is crucial to know the model's approximate performance. To evaluate performance, a set of labeled test instances is required that is drawn from the distribution the model will be exposed to at application time. In many practical scenarios, unlabeled test instances are readily available, but the process of labeling them can be a time- and cost-intensive task and may involve a human expert. This thesis addresses the problem of evaluating a given predictive model accurately with minimal labeling effort. We study an active model evaluation process that selects certain instances of the data according to an instrumental sampling distribution and queries their labels. We derive sampling distributions that minimize estimation error with respect to different performance measures such as error rate, mean squared error, and F-measures. An analysis of the distribution that governs the estimator leads to confidence intervals, which indicate how precise the error estimation is. Labeling costs may vary across different instances depending on certain characteristics of the data. For instance, documents differ in their length, comprehensibility, and technical requirements; these attributes affect the time a human labeler needs to judge relevance or to assign topics. To address this, the sampling distribution is extended to incorporate instance-specific costs. We empirically study conditions under which the active evaluation processes are more accurate than a standard estimate that draws equally many instances from the test distribution. We also address the problem of comparing the risks of two predictive models. The standard approach would be to draw instances according to the test distribution, label the selected instances, and apply statistical tests to identify significant differences. Drawing instances according to an instrumental distribution affects the power of a statistical test. We derive a sampling procedure that maximizes test power when used to select instances, and thereby minimizes the likelihood of choosing the inferior model. Furthermore, we investigate the task of comparing several alternative models; the objective of an evaluation could be to rank the models according to the risk that they incur or to identify the model with lowest risk. An experimental study shows that the active procedure leads to higher test power than the standard test in many application domains. Finally, we study the problem of evaluating the performance of ranking functions, which are used for example for web search. In practice, ranking performance is estimated by applying a given ranking model to a representative set of test queries and manually assessing the relevance of all retrieved items for each query. We apply the concepts of active evaluation and active comparison to ranking functions and derive optimal sampling distributions for the commonly used performance measures Discounted Cumulative Gain and Expected Reciprocal Rank. Experiments on web search engine data illustrate significant reductions in labeling costs.},
language = {en}
}
@phdthesis{Bauckmann2013,
author = {Bauckmann, Jana},
title = {Dependency discovery for data integration},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-66645},
school = {Universit{\"a}t Potsdam},
year = {2013},
abstract = {Data integration aims to combine data of different sources and to provide users with a unified view on these data. This task is as challenging as valuable. In this thesis we propose algorithms for dependency discovery to provide necessary information for data integration. We focus on inclusion dependencies (INDs) in general and a special form named conditional inclusion dependencies (CINDs): (i) INDs enable the discovery of structure in a given schema. (ii) INDs and CINDs support the discovery of cross-references or links between schemas. An IND "A in B" simply states that all values of attribute A are included in the set of values of attribute B. We propose an algorithm that discovers all inclusion dependencies in a relational data source. The challenge of this task is the complexity of testing all attribute pairs and further of comparing all of each attribute pair's values. The complexity of existing approaches depends on the number of attribute pairs, while ours depends only on the number of attributes. Thus, our algorithm enables to profile entirely unknown data sources with large schemas by discovering all INDs. Further, we provide an approach to extract foreign keys from the identified INDs. We extend our IND discovery algorithm to also find three special types of INDs: (i) Composite INDs, such as "AB in CD", (ii) approximate INDs that allow a certain amount of values of A to be not included in B, and (iii) prefix and suffix INDs that represent special cross-references between schemas. Conditional inclusion dependencies are inclusion dependencies with a limited scope defined by conditions over several attributes. Only the matching part of the instance must adhere the dependency. We generalize the definition of CINDs distinguishing covering and completeness conditions and define quality measures for conditions. We propose efficient algorithms that identify covering and completeness conditions conforming to given quality thresholds. The challenge for this task is twofold: (i) Which (and how many) attributes should be used for the conditions? (ii) Which attribute values should be chosen for the conditions? Previous approaches rely on pre-selected condition attributes or can only discover conditions applying to quality thresholds of 100\%. Our approaches were motivated by two application domains: data integration in the life sciences and link discovery for linked open data. We show the efficiency and the benefits of our approaches for use cases in these domains.},
language = {en}
}
@book{HerzbergWeske2013,
author = {Herzberg, Nico and Weske, Mathias},
title = {Enriching raw events to enable process intelligence : research challenges},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-241-4},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-64012},
publisher = {Universit{\"a}t Potsdam},
pages = {30},
year = {2013},
abstract = {Business processes are performed within a company's daily business. Thereby, valuable data about the process execution is produced. The quantity and quality of this data is very dependent on the process execution environment that reaches from predominantly manual to fullautomated. Process improvement is one essential cornerstone of business process management to ensure companies' competitiveness and relies on information about the process execution. Especially in manual process environments data directly related to the process execution is rather sparse and incomplete. In this paper, we present an approach that supports the usage and enrichment of process execution data with context data - data that exists orthogonally to business process data - and knowledge from the corresponding process models to provide a high-quality event base for process intelligence subsuming, among others, process monitoring, process analysis, and process mining. Further, we discuss open issues and challenges that are subject to our future work.},
language = {de}
}
@article{HofukuChoNishidaetal.2013,
author = {Hofuku, Yoyoi and Cho, Shinya and Nishida, Tomohiro and Kanemune, Susumu},
title = {Why is programming difficult?},
series = {Commentarii informaticae didacticae : (CID)},
journal = {Commentarii informaticae didacticae : (CID)},
number = {6},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-64458},
pages = {13 -- 24},
year = {2013},
abstract = {In this article, we propose a model for an understanding process that learners can use while studying programming. We focus on the "small step" method, in which students learn only a few concepts for one program to avoid having trouble with learning programming. We also analyze the difference in the description order between several C programming textbooks on the basis of the model. We developed a tool to detect "gaps" (a lot of concepts to be learned in a program) in programming textbooks.},
language = {de}
}
@article{Linck2013,
author = {Linck, Barbara},
title = {Test items for and misconceptions of competences in the domain of logic programming},
series = {Commentarii informaticae didacticae : (CID)},
journal = {Commentarii informaticae didacticae : (CID)},
number = {6},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-64461},
pages = {25 -- 34},
year = {2013},
abstract = {Development of competence-oriented curricula is still an important theme in informatics education. Unfortunately informatics curricula, which include the domain of logic programming, are still input-orientated or lack detailed competence descriptions. Therefore, the development of competence model and of learning outcomes' descriptions is essential for the learning process in this domain. A prior research developed both. The next research step is to formulate test items to measure the described learning outcomes. This article describes this procedure and exemplifies test items. It also relates a test in school to the items and shows which misconceptions and typical errors are important to discuss in class. The test result can also confirm or disprove the competence model. Therefore, this school test is important for theoretical research as well as for the concrete planning of lessons. Quantitative analysis in school is important for evaluation and improvement of informatics education.},
language = {en}
}
@article{KimPark2013,
author = {Kim, Seungyon and Park, Seongbin},
title = {Teaching NP completeness in secondary schools},
series = {Commentarii informaticae didacticae : (CID)},
journal = {Commentarii informaticae didacticae : (CID)},
number = {6},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-64476},
pages = {35 -- 38},
year = {2013},
abstract = {In this paper, we show how the theory of NP completeness can be introduced to students in secondary schools. The motivation of this research is that although there are difficult issues that require technical backgrounds, students are already familiar with demanding computational problems through games such as Sudoku or Tetris. Our intention is to bring together important concepts in the theory of NP completeness in such a way that students in secondary schools can easily understand them. This is part of our ongoing research about how to teach fundamental issues in Computer Science in secondary schools. We discuss what needs to be taught in which sequence in order to introduce ideas behind NP completeness to students without technical backgrounds.},
language = {en}
}
@article{Vaniček2013,
author = {Van{\´i}ček, Jiř{\´i}},
title = {Introducing topics from informatics into primary school curricula},
series = {Commentarii informaticae didacticae : (CID)},
journal = {Commentarii informaticae didacticae : (CID)},
number = {6},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-64482},
pages = {41 -- 51},
year = {2013},
abstract = {The process of introducing compulsory ICT education at primary school level in the Czech Republic should be completed next year. Programming and Information, two topics from the basics of computer science have been included in a new textbook. The question is whether the new chapters of the textbook are comprehensible for primary school teachers, who have undergone no training in computer science. The paper reports on a pilot verification project in which pre-service primary school teachers were trained to teach these informatics topics.},
language = {en}
}
@book{MeyerPufahlFahlandetal.2013,
author = {Meyer, Andreas and Pufahl, Luise and Fahland, Dirk and Weske, Mathias},
title = {Modeling and enacting complex data dependencies in business processes},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-245-2},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-65103},
publisher = {Universit{\"a}t Potsdam},
pages = {40},
year = {2013},
abstract = {Enacting business processes in process engines requires the coverage of control flow, resource assignments, and process data. While the first two aspects are well supported in current process engines, data dependencies need to be added and maintained manually by a process engineer. Thus, this task is error-prone and time-consuming. In this report, we address the problem of modeling processes with complex data dependencies, e.g., m:n relationships, and their automatic enactment from process models. First, we extend BPMN data objects with few annotations to allow data dependency handling as well as data instance differentiation. Second, we introduce a pattern-based approach to derive SQL queries from process models utilizing the above mentioned extensions. Therewith, we allow automatic enactment of data-aware BPMN process models. We implemented our approach for the Activiti process engine to show applicability.},
language = {en}
}
@phdthesis{Doerge2015,
author = {D{\"o}rge, Christina},
title = {Informatische Schl{\"u}sselkompetenzen},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-262-9},
issn = {1868-0844},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-70470},
school = {Universit{\"a}t Potsdam},
pages = {458},
year = {2015},
abstract = {Seit den 60er Jahren gibt es im deutschsprachigen Raum Diskussionen um die Begriffe Schl{\"u}sselqualifikation und (Schl{\"u}ssel-)Kompetenz, welche seit ca. 2000 auch in der Informatikdidaktik angekommen sind. Die Diskussionen der Fachdisziplinen und ihre Bedeutung f{\"u}r die Informatikdidaktik sind Gegenstand des ersten Teils dieser Dissertation. Es werden Rahmenmodelle zur Strukturierung und Einordnung von Kompetenzen entworfen, die f{\"u}r alle Fachdisziplinen nutzbar sind. Im zweiten Teil wird ein methodologischer Weg gezeigt, Schl{\"u}sselkompetenzen herzuleiten, ohne normativ vorgehen zu m{\"u}ssen. Hierzu wird das Verfahren der Qualitativen Inhaltsanalyse (QI) auf informatikdidaktische Ansätze angewendet. Die resultierenden Kompetenzen werden in weiteren Schritten verfeinert und in die zuvor entworfenen Rahmenmodelle eingeordnet. Das Ergebnis sind informatische Schl{\"u}sselkompetenzen, welche ein spezifisches Bild der Informatik zeichnen und zur Analyse bereits bestehender Curricula genutzt werden können. Zusätzlich zeigt das Verfahren einen Weg auf, wie Schl{\"u}sselkompetenzen auf nicht-normativem Wege generell hergeleitet werden können.},
language = {de}
}
@phdthesis{Tinnefeld2014,
author = {Tinnefeld, Christian},
title = {Building a columnar database on shared main memory-based storage},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-72063},
school = {Universit{\"a}t Potsdam},
pages = {175},
year = {2014},
abstract = {In the field of disk-based parallel database management systems exists a great variety of solutions based on a shared-storage or a shared-nothing architecture. In contrast, main memory-based parallel database management systems are dominated solely by the shared-nothing approach as it preserves the in-memory performance advantage by processing data locally on each server. We argue that this unilateral development is going to cease due to the combination of the following three trends: a) Nowadays network technology features remote direct memory access (RDMA) and narrows the performance gap between accessing main memory inside a server and of a remote server to and even below a single order of magnitude. b) Modern storage systems scale gracefully, are elastic, and provide high-availability. c) A modern storage system such as Stanford's RAMCloud even keeps all data resident in main memory. Exploiting these characteristics in the context of a main-memory parallel database management system is desirable. The advent of RDMA-enabled network technology makes the creation of a parallel main memory DBMS based on a shared-storage approach feasible. This thesis describes building a columnar database on shared main memory-based storage. The thesis discusses the resulting architecture (Part I), the implications on query processing (Part II), and presents an evaluation of the resulting solution in terms of performance, high-availability, and elasticity (Part III). In our architecture, we use Stanford's RAMCloud as shared-storage, and the self-designed and developed in-memory AnalyticsDB as relational query processor on top. AnalyticsDB encapsulates data access and operator execution via an interface which allows seamless switching between local and remote main memory, while RAMCloud provides not only storage capacity, but also processing power. Combining both aspects allows pushing-down the execution of database operators into the storage system. We describe how the columnar data processed by AnalyticsDB is mapped to RAMCloud's key-value data model and how the performance advantages of columnar data storage can be preserved. The combination of fast network technology and the possibility to execute database operators in the storage system opens the discussion for site selection. We construct a system model that allows the estimation of operator execution costs in terms of network transfer, data processed in memory, and wall time. This can be used for database operators that work on one relation at a time - such as a scan or materialize operation - to discuss the site selection problem (data pull vs. operator push). Since a database query translates to the execution of several database operators, it is possible that the optimal site selection varies per operator. For the execution of a database operator that works on two (or more) relations at a time, such as a join, the system model is enriched by additional factors such as the chosen algorithm (e.g. Grace- vs. Distributed Block Nested Loop Join vs. Cyclo-Join), the data partitioning of the respective relations, and their overlapping as well as the allowed resource allocation. We present an evaluation on a cluster with 60 nodes where all nodes are connected via RDMA-enabled network equipment. We show that query processing performance is about 2.4x slower if everything is done via the data pull operator execution strategy (i.e. RAMCloud is being used only for data access) and about 27\% slower if operator execution is also supported inside RAMCloud (in comparison to operating only on main memory inside a server without any network communication at all). The fast-crash recovery feature of RAMCloud can be leveraged to provide high-availability, e.g. a server crash during query execution only delays the query response for about one second. Our solution is elastic in a way that it can adapt to changing workloads a) within seconds, b) without interruption of the ongoing query processing, and c) without manual intervention.},
language = {en}
}
@article{Frank2012,
author = {Frank, Mario},
title = {Axiom relevance decision engine : technical report},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-72128},
year = {2012},
abstract = {This document presents an axiom selection technique for classic first order theorem proving based on the relevance of axioms for the proof of a conjecture. It is based on unifiability of predicates and does not need statistical information like symbol frequency. The scope of the technique is the reduction of the set of axioms and the increase of the amount of provable conjectures in a given time. Since the technique generates a subset of the axiom set, it can be used as a preprocessor for automated theorem proving. This technical report describes the conception, implementation and evaluation of ARDE. The selection method, which is based on a breadth-first graph search by unifiability of predicates, is a weakened form of the connection calculus and uses specialised variants or unifiability to speed up the selection. The implementation of the concept is evaluated with comparison to the results of the world championship of theorem provers of the year 2012 (CASC J6). It is shown that both the theorem prover leanCoP which uses the connection calculus and E which uses equality reasoning, can benefit from the selection approach. Also, the evaluation shows that the concept is applyable for theorem proving problems with thousands of formulae and that the selection is independent from the calculus used by the theorem prover.},
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}
}
@book{HebigGieseBatoulisetal.2015,
author = {Hebig, Regina and Giese, Holger and Batoulis, Kimon and Langer, Philipp and Zamani Farahani, Armin and Yao, Gary and Wolowyk, Mychajlo},
title = {Development of AUTOSAR standard documents at Carmeq GmbH},
number = {92},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-317-6},
issn = {1613-5652},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-71535},
publisher = {Universit{\"a}t Potsdam},
pages = {52},
year = {2015},
abstract = {This report documents the captured MDE history of Carmeq GmbH, in context of the project Evolution of MDE Settings in Practice. The goal of the project is the elicitation of MDE approaches and their evolution.},
language = {en}
}
@phdthesis{Lindauer2014,
author = {Lindauer, T. Marius},
title = {Algorithm selection, scheduling and configuration of Boolean constraint solvers},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-71260},
school = {Universit{\"a}t Potsdam},
pages = {ii, 130},
year = {2014},
abstract = {Boolean constraint solving technology has made tremendous progress over the last decade, leading to industrial-strength solvers, for example, in the areas of answer set programming (ASP), the constraint satisfaction problem (CSP), propositional satisfiability (SAT) and satisfiability of quantified Boolean formulas (QBF). However, in all these areas, there exist multiple solving strategies that work well on different applications; no strategy dominates all other strategies. Therefore, no individual solver shows robust state-of-the-art performance in all kinds of applications. Additionally, the question arises how to choose a well-performing solving strategy for a given application; this is a challenging question even for solver and domain experts. One way to address this issue is the use of portfolio solvers, that is, a set of different solvers or solver configurations. We present three new automatic portfolio methods: (i) automatic construction of parallel portfolio solvers (ACPP) via algorithm configuration,(ii) solving the \$NP\$-hard problem of finding effective algorithm schedules with Answer Set Programming (aspeed), and (iii) a flexible algorithm selection framework (claspfolio2) allowing for fair comparison of different selection approaches. All three methods show improved performance and robustness in comparison to individual solvers on heterogeneous instance sets from many different applications. Since parallel solvers are important to effectively solve hard problems on parallel computation systems (e.g., multi-core processors), we extend all three approaches to be effectively applicable in parallel settings. We conducted extensive experimental studies different instance sets from ASP, CSP, MAXSAT, Operation Research (OR), SAT and QBF that indicate an improvement in the state-of-the-art solving heterogeneous instance sets. Last but not least, from our experimental studies, we deduce practical advice regarding the question when to apply which of our methods.},
language = {en}
}
@phdthesis{Becker2013,
author = {Becker, Basil},
title = {Architectural modelling and verification of open service-oriented systems of systems},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-70158},
school = {Universit{\"a}t Potsdam},
year = {2013},
abstract = {Systems of Systems (SoS) have received a lot of attention recently. In this thesis we will focus on SoS that are built atop the techniques of Service-Oriented Architectures and thus combine the benefits and challenges of both paradigms. For this thesis we will understand SoS as ensembles of single autonomous systems that are integrated to a larger system, the SoS. The interesting fact about these systems is that the previously isolated systems are still maintained, improved and developed on their own. Structural dynamics is an issue in SoS, as at every point in time systems can join and leave the ensemble. This and the fact that the cooperation among the constituent systems is not necessarily observable means that we will consider these systems as open systems. Of course, the system has a clear boundary at each point in time, but this can only be identified by halting the complete SoS. However, halting a system of that size is practically impossible. Often SoS are combinations of software systems and physical systems. Hence a failure in the software system can have a serious physical impact what makes an SoS of this kind easily a safety-critical system. The contribution of this thesis is a modelling approach that extends OMG's SoaML and basically relies on collaborations and roles as an abstraction layer above the components. This will allow us to describe SoS at an architectural level. We will also give a formal semantics for our modelling approach which employs hybrid graph-transformation systems. The modelling approach is accompanied by a modular verification scheme that will be able to cope with the complexity constraints implied by the SoS' structural dynamics and size. Building such autonomous systems as SoS without evolution at the architectural level --- i. e. adding and removing of components and services --- is inadequate. Therefore our approach directly supports the modelling and verification of evolution.},
language = {en}
}
@phdthesis{Hebig2014,
author = {Hebig, Regina},
title = {Evolution of model-driven engineering settings in practice},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-70761},
school = {Universit{\"a}t Potsdam},
year = {2014},
abstract = {Nowadays, software systems are getting more and more complex. To tackle this challenge most diverse techniques, such as design patterns, service oriented architectures (SOA), software development processes, and model-driven engineering (MDE), are used to improve productivity, while time to market and quality of the products stay stable. Multiple of these techniques are used in parallel to profit from their benefits. While the use of sophisticated software development processes is standard, today, MDE is just adopted in practice. However, research has shown that the application of MDE is not always successful. It is not fully understood when advantages of MDE can be used and to what degree MDE can also be disadvantageous for productivity. Further, when combining different techniques that aim to affect the same factor (e.g. productivity) the question arises whether these techniques really complement each other or, in contrast, compensate their effects. Due to that, there is the concrete question how MDE and other techniques, such as software development process, are interrelated. Both aspects (advantages and disadvantages for productivity as well as the interrelation to other techniques) need to be understood to identify risks relating to the productivity impact of MDE. Before studying MDE's impact on productivity, it is necessary to investigate the range of validity that can be reached for the results. This includes two questions. First, there is the question whether MDE's impact on productivity is similar for all approaches of adopting MDE in practice. Second, there is the question whether MDE's impact on productivity for an approach of using MDE in practice remains stable over time. The answers for both questions are crucial for handling risks of MDE, but also for the design of future studies on MDE success. This thesis addresses these questions with the goal to support adoption of MDE in future. To enable a differentiated discussion about MDE, the term MDE setting'' is introduced. MDE setting refers to the applied technical setting, i.e. the employed manual and automated activities, artifacts, languages, and tools. An MDE setting's possible impact on productivity is studied with a focus on changeability and the interrelation to software development processes. This is done by introducing a taxonomy of changeability concerns that might be affected by an MDE setting. Further, three MDE traits are identified and it is studied for which manifestations of these MDE traits software development processes are impacted. To enable the assessment and evaluation of an MDE setting's impacts, the Software Manufacture Model language is introduced. This is a process modeling language that allows to reason about how relations between (modeling) artifacts (e.g. models or code files) change during application of manual or automated development activities. On that basis, risk analysis techniques are provided. These techniques allow identifying changeability risks and assessing the manifestations of the MDE traits (and with it an MDE setting's impact on software development processes). To address the range of validity, MDE settings from practice and their evolution histories were capture in context of this thesis. First, this data is used to show that MDE settings cover the whole spectrum concerning their impact on changeability or interrelation to software development processes. Neither it is seldom that MDE settings are neutral for processes nor is it seldom that MDE settings have impact on processes. Similarly, the impact on changeability differs relevantly. Second, a taxonomy of evolution of MDE settings is introduced. In that context it is discussed to what extent different types of changes on an MDE setting can influence this MDE setting's impact on changeability and the interrelation to processes. The category of structural evolution, which can change these characteristics of an MDE setting, is identified. The captured MDE settings from practice are used to show that structural evolution exists and is common. In addition, some examples of structural evolution steps are collected that actually led to a change in the characteristics of the respective MDE settings. Two implications are: First, the assessed diversity of MDE settings evaluates the need for the analysis techniques that shall be presented in this thesis. Second, evolution is one explanation for the diversity of MDE settings in practice. To summarize, this thesis studies the nature and evolution of MDE settings in practice. As a result support for the adoption of MDE settings is provided in form of techniques for the identification of risks relating to productivity impacts.},
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}
}
@phdthesis{Lange2013,
author = {Lange, Dustin},
title = {Effective and efficient similarity search in databases},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-65712},
school = {Universit{\"a}t Potsdam},
year = {2013},
abstract = {Given a large set of records in a database and a query record, similarity search aims to find all records sufficiently similar to the query record. To solve this problem, two main aspects need to be considered: First, to perform effective search, the set of relevant records is defined using a similarity measure. Second, an efficient access method is to be found that performs only few database accesses and comparisons using the similarity measure. This thesis solves both aspects with an emphasis on the latter. In the first part of this thesis, a frequency-aware similarity measure is introduced. Compared record pairs are partitioned according to frequencies of attribute values. For each partition, a different similarity measure is created: machine learning techniques combine a set of base similarity measures into an overall similarity measure. After that, a similarity index for string attributes is proposed, the State Set Index (SSI), which is based on a trie (prefix tree) that is interpreted as a nondeterministic finite automaton. For processing range queries, the notion of query plans is introduced in this thesis to describe which similarity indexes to access and which thresholds to apply. The query result should be as complete as possible under some cost threshold. Two query planning variants are introduced: (1) Static planning selects a plan at compile time that is used for all queries. (2) Query-specific planning selects a different plan for each query. For answering top-k queries, the Bulk Sorted Access Algorithm (BSA) is introduced, which retrieves large chunks of records from the similarity indexes using fixed thresholds, and which focuses its efforts on records that are ranked high in more than one attribute and thus promising candidates. The described components form a complete similarity search system. Based on prototypical implementations, this thesis shows comparative evaluation results for all proposed approaches on different real-world data sets, one of which is a large person data set from a German credit rating agency.},
language = {en}
}
@book{CalmezHesseSiegmundetal.2013,
author = {Calmez, Conrad and Hesse, Hubert and Siegmund, Benjamin and Stamm, Sebastian and Thomschke, Astrid and Hirschfeld, Robert and Ingalls, Dan and Lincke, Jens},
title = {Explorative authoring of Active Web content in a mobile environment},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-232-2},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-64054},
publisher = {Universit{\"a}t Potsdam},
pages = {132},
year = {2013},
abstract = {Developing rich Web applications can be a complex job - especially when it comes to mobile device support. Web-based environments such as Lively Webwerkstatt can help developers implement such applications by making the development process more direct and interactive. Further the process of developing software is collaborative which creates the need that the development environment offers collaboration facilities. This report describes extensions of the webbased development environment Lively Webwerkstatt such that it can be used in a mobile environment. The extensions are collaboration mechanisms, user interface adaptations but as well event processing and performance measuring on mobile devices.},
language = {en}
}
@book{WistWollowski2007,
author = {Wist, Dominic and Wollowski, Ralf},
title = {STG decomposition : avoiding irreducible CSC conflicts by internal communication},
isbn = {978-3-940793-02-7},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-32968},
publisher = {Universit{\"a}t Potsdam},
year = {2007},
abstract = {Inhalt: 1 Introduction 2 Basic Definitions 3 Achieving SI Implementability by Internal Communication 4 Towards a Structural Method 5 Examples 6 Conclusions and Future Work},
language = {en}
}
@book{OPUS4-3141,
title = {Java language conversion assistant : an analysis},
editor = {Richter, Stefan and Henze, Stefan and B{\"u}ttner, Eiko and Bach, Steffen and Polze, Andreas},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-937786-10-0},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-33151},
publisher = {Universit{\"a}t Potsdam},
pages = {166},
year = {2004},
abstract = {This document is an analysis of the 'Java Language Conversion Assistant'. Itr will also cover a language analysis of the Java Programming Language as well as a survey of related work concerning Java and C\# interoperability on the one hand and language conversion in general on the other. Part I deals with language analysis. Part II covers the JLCA tool and tests used to analyse the tool. Additionally, it gives an overview of the above mentioned related work. Part III presents a complete project that has been translated using the JLCA.},
language = {en}
}
@book{OPUS4-3143,
title = {Conceptual architecture patterns : FMC-based representations},
editor = {Gr{\"o}ne, Bernhard and Keller, Frank},
isbn = {978-3-935024-98-3},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-33173},
publisher = {Universit{\"a}t Potsdam},
year = {2004},
abstract = {This document presents the results of the seminar "Coneptual Arachitecture Patterns" of the winter term 2002 in the Hasso-Plattner-Institute. It is a compilation of the student's elaborations dealing with some conceptual architecture patterns which can be found in literature. One important focus laid on the runtime structures and the presentation of the patterns. 1. Introduction 1.1. The Seminar 1.2. Literature 2 Pipes and Filters (Andr{\´e} Langhorst and Martin Steinle) 3 Broker (Konrad H{\"u}bner and Einar L{\"u}ck) 4 Microkernel (Eiko B{\"u}ttner and Stefan Richter) 5 Component Configurator (Stefan R{\"o}ck and Alexander Gierak) 6 Interceptor (Marc F{\"o}rster and Peter Aschenbrenner) 7 Reactor (Nikolai Cieslak and Dennis Eder) 8 Half-Sync/Half-Async (Robert Mitschke and Harald Schubert) 9 Leader/Followers (Dennis Klemann and Steffen Schmidt)},
language = {en}
}
@book{KuropkaMeyer2005,
author = {Kuropka, Dominik and Meyer, Harald},
title = {Survey on Service Composition},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {3-937786-78-3},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-33787},
publisher = {Universit{\"a}t Potsdam},
pages = {35},
year = {2005},
abstract = {It is predicted that Service-oriented Architectures (SOA) will have a high impact on future electronic business and markets. Services will provide an self-contained and standardised interface towards business and are considered as the future platform for business-to-business and business-toconsumer trades. Founded by the complexity of real world business scenarios a huge need for an easy, flexible and automated creation and enactment of service compositions is observed. This survey explores the relationship of service composition with workflow management—a technology/ concept already in use in many business environments. The similarities between the both and the key differences between them are elaborated. Furthermore methods for composition of services ranging from manual, semi- to full-automated composition are sketched. This survey concludes that current tools for service composition are in an immature state and that there is still much research to do before service composition can be used easily and conveniently in real world scenarios. However, since automated service composition is a key enabler for the full potential of Service-oriented Architectures, further research on this field is imperative. This survey closes with a formal sample scenario presented in appendix A to give the reader an impression on how full-automated service composition works.},
language = {en}
}
@book{AdamBrehmerHuettenrauchetal.2006,
author = {Adam, Christian and Brehmer, Bastian and H{\"u}ttenrauch, Stefan and Jeske, Janin and Polze, Andreas and Rasche, Andreas and Sch{\"u}ler, Benjamin and Schult, Wolfgang},
title = {Aspektorientierte Programmierung : {\"U}berblick {\"u}ber Techniken und Werkzeuge},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-939469-23-0},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-33796},
publisher = {Universit{\"a}t Potsdam},
pages = {88},
year = {2006},
abstract = {Inhaltsverzeichnis 1 Einf{\"u}hrung 2 Aspektorientierte Programmierung 2.1 Ein System als Menge von Eigenschaften 2.2 Aspekte 2.3 Aspektweber 2.4 Vorteile Aspektorientierter Programmierung 2.5 Kategorisierung der Techniken und Werkzeuge f ¨ ur Aspektorientierte Programmierung 3 Techniken und Werkzeuge zur Analyse Aspektorientierter Softwareprogramme 3.1 Virtual Source File 3.2 FEAT 3.3 JQuery 3.4 Aspect Mining Tool 4 Techniken und Werkzeuge zum Entwurf Aspektorientierter Softwareprogramme 4.1 Concern Space Modeling Schema 4.2 Modellierung von Aspekten mit UML 4.3 CoCompose 4.4 Codagen Architect 5 Techniken und Werkzeuge zur Implementierung Aspektorientierter Softwareprogramme 5.1 Statische Aspektweber 5.2 Dynamische Aspektweber 6 Zusammenfassung},
language = {de}
}
@book{GroeneKnoepfelKugeletal.2004,
author = {Gr{\"o}ne, Bernhard and Kn{\"o}pfel, Andreas and Kugel, Rudolf and Schmidt, Oliver},
title = {The Apache Modeling Project},
isbn = {978-3-937786-14-8},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-33147},
publisher = {Universit{\"a}t Potsdam},
year = {2004},
abstract = {This document presents an introduction to the Apache HTTP Server, covering both an overview and implementation details. It presents results of the Apache Modelling Project done by research assistants and students of the Hasso-Plattner-Institute in 2001, 2002 and 2003. The Apache HTTP Server was used to introduce students to the application of the modeling technique FMC, a method that supports transporting knowledge about complex systems in the domain of information processing (software and hardware as well). After an introduction to HTTP servers in general, we will focus on protocols and web technology. Then we will discuss Apache, its operational environment and its extension capabilities— the module API. Finally we will guide the reader through parts of the Apache source code and explain the most important pieces.},
language = {en}
}
@inproceedings{PalixLawallThomasetal.2010,
author = {Palix, Nicolas and Lawall, Julia L. and Thomas, Ga{\"e}l and Muller, Gilles},
title = {How Often do Experts Make Mistakes?},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-41327},
year = {2010},
abstract = {Large open-source software projects involve developers with a wide variety of backgrounds and expertise. Such software projects furthermore include many internal APIs that developers must understand and use properly. According to the intended purpose of these APIs, they are more or less frequently used, and used by developers with more or less expertise. In this paper, we study the impact of usage patterns and developer expertise on the rate of defects occurring in the use of internal APIs. For this preliminary study, we focus on memory management APIs in the Linux kernel, as the use of these has been shown to be highly error prone in previous work. We study defect rates and developer expertise, to consider e.g., whether widely used APIs are more defect prone because they are used by less experienced developers, or whether defects in widely used APIs are more likely to be fixed.},
language = {en}
}
@inproceedings{OPUS4-3948,
title = {Preface},
editor = {Adams, Bram and Haupt, Michael and Lohmann, Daniel},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-41338},
year = {2010},
abstract = {Aspect-oriented programming, component models, and design patterns are modern and actively evolving techniques for improving the modularization of complex software. In particular, these techniques hold great promise for the development of "systems infrastructure" software, e.g., application servers, middleware, virtual machines, compilers, operating systems, and other software that provides general services for higher-level applications. The developers of infrastructure software are faced with increasing demands from application programmers needing higher-level support for application development. Meeting these demands requires careful use of software modularization techniques, since infrastructural concerns are notoriously hard to modularize. Aspects, components, and patterns provide very different means to deal with infrastructure software, but despite their differences, they have much in common. For instance, component models try to free the developer from the need to deal directly with services like security or transactions. These are primary examples of crosscutting concerns, and modularizing such concerns are the main target of aspect-oriented languages. Similarly, design patterns like Visitor and Interceptor facilitate the clean modularization of otherwise tangled concerns. Building on the ACP4IS meetings at AOSD 2002-2009, this workshop aims to provide a highly interactive forum for researchers and developers to discuss the application of and relationships between aspects, components, and patterns within modern infrastructure software. The goal is to put aspects, components, and patterns into a common reference frame and to build connections between the software engineering and systems communities.},
language = {en}
}
@inproceedings{BynensVanLanduytTruyenetal.2010,
author = {Bynens, Maarten and Van Landuyt, Dimitri and Truyen, Eddy and Joosen, Wouter},
title = {Towards reusable aspects: the callback mismatch problem},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-41347},
year = {2010},
abstract = {Because software development is increasingly expensive and timeconsuming, software reuse gains importance. Aspect-oriented software development modularizes crosscutting concerns which enables their systematic reuse. Literature provides a number of AOP patterns and best practices for developing reusable aspects based on compelling examples for concerns like tracing, transactions and persistence. However, such best practices are lacking for systematically reusing invasive aspects. In this paper, we present the 'callback mismatch problem'. This problem arises in the context of abstraction mismatch, in which the aspect is required to issue a callback to the base application. As a consequence, the composition of invasive aspects is cumbersome to implement, difficult to maintain and impossible to reuse. We motivate this problem in a real-world example, show that it persists in the current state-of-the-art, and outline the need for advanced aspectual composition mechanisms to deal with this.},
language = {en}
}
@book{Freischlad2009,
author = {Freischlad, Stefan},
title = {Entwicklung und Erprobung des Didaktischen Systems Internetworking im Informatikunterricht},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-058-8},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-41851},
publisher = {Universit{\"a}t Potsdam},
pages = {XIV, 405},
year = {2009},
abstract = {Internetbasierte Informatiksysteme beeinflussen in steigendem Maße Situationen in unterschiedlichen Lebensbereichen. Kompetenzen zur Verwendung von Internetanwendungen und -diensten m{\"u}ssen explizit erworben werden, weil damit ein notwendiger Einblick in nicht beobachtbare Abl{\"a}ufe und nicht offen sichtbare Strukturen verbunden ist. Bisher gibt es Vorschl{\"a}ge f{\"u}r die Gestaltung schulischer Lehr-Lernprozesse zu ausgew{\"a}hlten Teilaspekten des Internets. Es fehlt eine systematische Analyse des Bildungsbedarfs und ein daraus resultierendes Unterrichtsmodell. In dieser Arbeit wird ein Gesamtkonzept f{\"u}r den Informatikunterricht in der Sekundarstufe II vorgestellt, das zu zielgerichteter und verantwortungsvoller Anwendung des Internets beitr{\"a}gt. Die vorliegende Arbeit umfasst den Prozess von der Analyse erforderlicher Kompetenzen bis zur Realisierung von Lehr-Lernprozessen im Informatikunterricht in der Sekundarstufe II. Es werden der Beitrag der Informatik zu identifizierten Kompetenzen untersucht und Bildungsanforderungen bestimmt. Bildungsempfehlungen und Forschungsergebnisse zu erfolgreichen Unterrichtseinheiten werden im Hinblick auf die Bildungsziele analysiert. Der Informatikunterricht unterst{\"u}tzt die Kompetenzentwicklung zu internetbasierten digitalen Medien. Es wird die Entwicklung eines Unterrichtsmodells zu Internetworking beschrieben. Dazu wird der Ansatz der Didaktischen Systeme untersucht, weiter entwickelt und auf den Bereich Internetworking {\"u}bertragen. Der theoretische Ansatz wird dazu in vier Unterrichtsprojekten zu Internetworking in der Praxis realisiert. Beziehungen zwischen Fachkonzepten zu Internetworking werden untersucht und durch Wissensstrukturen zur Planung von Unterrichtsprojekten eingesetzt und in der Praxis erprobt. Die Beschreibung von Lernaktivit{\"a}ten erfolgt auf der Basis von Aufgabenklassen, die das notwendige Wissen zur Bearbeitung einer Aufgabenstellung repr{\"a}sentieren. Auf der Grundlage des Ablaufs der Aufgabenbearbeitung werden Eigenschaften von Aufgaben beschrieben und zu deren Gestaltung nutzbar gemacht. Bisher nicht durchf{\"u}hrbare T{\"a}tigkeiten im Unterricht werden durch die Entwicklung der Lernsoftware Filius erm{\"o}glicht. Die Reduktion der komplexen Wirklichkeit durch Simulation realer internetbasierter Informatiksysteme und die Auswahl geeigneter Sichten auf den Untersuchungsgegenstand werden mit Ergebnissen der Informatikdidaktik begr{\"u}ndet. Unterrichtsprojekte zu den Zielen werden durchgef{\"u}hrt, um Lehr-Lernprozesse zu erkunden und das entwickelte Didaktische System zu erproben. Ausgehend von der theoretischen Fundierung erfolgt die praktische Realisierung von Lehr-Lernprozessen. Zur Erprobung im Informatikunterricht der Sekundarstufe II in Nordrhein-Westfalen werden Minimalziele aufgrund der Lehrvorgaben bestimmt. Die methodische Gestaltung in der Erprobung erfolgt unter Ber{\"u}cksichtigung der Vorgaben f{\"u}r den Informatikunterricht und allgemeinen Anforderungen der Fachdidaktik. Handlungsorientierte Unterrichtsmittel werden ausgew{\"a}hlt und in der Praxis zur Untersuchung der Lehr-Lernprozesse verwendet. Im Unterricht identifizierte Lernschwierigkeiten f{\"u}hren zur Modifikation der Wissensstrukturen und werden im Entwicklungsprozess von Filius ber{\"u}cksichtigt. Die Erkenntnisse aus Unterrichtsprojekten werden genutzt, um zu bestimmen, zu welchen Aufgabenklassen weitere Aufgaben erforderlich sind und inwieweit das aus den identifizierten Merkmalen abgeleitete Vorgehen zur Entwicklung niveaubestimmender Aufgaben genutzt werden kann. Die Erprobungen best{\"a}tigen die Tragf{\"a}higkeit des Didaktischen Systems Internetworking und leisten mit der Implementierung in der Praxis einen Beitrag zur Untersuchung von Kompetenzentwicklung im Informatikunterricht. Mit dem Didaktischen System Internetworking wird ein theoretisch fundiertes und empirisch erprobtes Unterrichtsmodell zur Entwicklung von Kompetenzen zur Einrichtung und Anwendung internetbasierter Informatiksysteme beschrieben.},
language = {de}
}
@inproceedings{GoltzPieth2010,
author = {Goltz, Hans-Joachim and Pieth, Norbert},
title = {A tool for generating partition schedules of multiprocessor systems},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-41556},
year = {2010},
abstract = {A deterministic cycle scheduling of partitions at the operating system level is supposed for a multiprocessor system. In this paper, we propose a tool for generating such schedules. We use constraint based programming and develop methods and concepts for a combined interactive and automatic partition scheduling system. This paper is also devoted to basic methods and techniques for modeling and solving this partition scheduling problem. Initial application of our partition scheduling tool has proved successful and demonstrated the suitability of the methods used.},
language = {en}
}
@phdthesis{Ishebabi2010,
author = {Ishebabi, Harold},
title = {Architecture synthesis for adaptive multiprocessor systems on chip},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-41316},
school = {Universit{\"a}t Potsdam},
year = {2010},
abstract = {This thesis presents methods for automated synthesis of flexible chip multiprocessor systems from parallel programs targeted at FPGAs to exploit both task-level parallelism and architecture customization. Automated synthesis is necessitated by the complexity of the design space. A detailed description of the design space is provided in order to determine which parameters should be modeled to facilitate automated synthesis by optimizing a cost function, the emphasis being placed on inclusive modeling of parameters from application, architectural and physical subspaces, as well as their joint coverage in order to avoid pre-constraining the design space. Given a parallel program and a set of an IP library, the automated synthesis problem is to simultaneously (i) select processors (ii) map and schedule tasks to them, and (iii) select one or several networks for inter-task communications such that design constraints and optimization objectives are met. The research objective in this thesis is to find a suitable model for automated synthesis, and to evaluate methods of using the model for architectural optimizations. Our contributions are a holistic approach for the design of such systems, corresponding models to facilitate automated synthesis, evaluation of optimization methods using state of the art integer linear and answer set programming, as well as the development of synthesis heuristics to solve runtime challenges.},
language = {en}
}
@inproceedings{Harrison2010,
author = {Harrison, William},
title = {Malleability, obliviousness and aspects for broadcast service attachment},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-41389},
year = {2010},
abstract = {An important characteristic of Service-Oriented Architectures is that clients do not depend on the service implementation's internal assignment of methods to objects. It is perhaps the most important technical characteristic that differentiates them from more common object-oriented solutions. This characteristic makes clients and services malleable, allowing them to be rearranged at run-time as circumstances change. That improvement in malleability is impaired by requiring clients to direct service requests to particular services. Ideally, the clients are totally oblivious to the service structure, as they are to aspect structure in aspect-oriented software. Removing knowledge of a method implementation's location, whether in object or service, requires re-defining the boundary line between programming language and middleware, making clearer specification of dependence on protocols, and bringing the transaction-like concept of failure scopes into language semantics as well. This paper explores consequences and advantages of a transition from object-request brokering to service-request brokering, including the potential to improve our ability to write more parallel software.},
language = {en}
}
@inproceedings{Schrijvers2010,
author = {Schrijvers, Tom},
title = {Overview of the monadic constraint programming framework},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-41411},
year = {2010},
abstract = {A constraint programming system combines two essential components: a constraint solver and a search engine. The constraint solver reasons about satisfiability of conjunctions of constraints, and the search engine controls the search for solutions by iteratively exploring a disjunctive search tree defined by the constraint program. The Monadic Constraint Programming framework gives a monadic definition of constraint programming where the solver is defined as a monad threaded through the monadic search tree. Search and search strategies can then be defined as firstclass objects that can themselves be built or extended by composable search transformers. Search transformers give a powerful and unifying approach to viewing search in constraint programming, and the resulting constraint programming system is first class and extremely flexible.},
language = {en}
}
@book{GellerHirschfeldBracha2010,
author = {Geller, Felix and Hirschfeld, Robert and Bracha, Gilad},
title = {Pattern Matching for an object-oriented and dynamically typed programming language},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-065-6},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-43035},
publisher = {Universit{\"a}t Potsdam},
pages = {81},
year = {2010},
abstract = {Pattern matching is a well-established concept in the functional programming community. It provides the means for concisely identifying and destructuring values of interest. This enables a clean separation of data structures and respective functionality, as well as dispatching functionality based on more than a single value. Unfortunately, expressive pattern matching facilities are seldomly incorporated in present object-oriented programming languages. We present a seamless integration of pattern matching facilities in an object-oriented and dynamically typed programming language: Newspeak. We describe language extensions to improve the practicability and integrate our additions with the existing programming environment for Newspeak. This report is based on the first author's master's thesis.},
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}
}
@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{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}
}
@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}
}
@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}
}
@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{Ziehe2005,
author = {Ziehe, Andreas},
title = {Blind source separation based on joint diagonalization of matrices with applications in biomedical signal processing},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-5694},
school = {Universit{\"a}t Potsdam},
year = {2005},
abstract = {This thesis is concerned with the solution of the blind source separation problem (BSS). The BSS problem occurs frequently in various scientific and technical applications. In essence, it consists in separating meaningful underlying components out of a mixture of a multitude of superimposed signals. In the recent research literature there are two related approaches to the BSS problem: The first is known as Independent Component Analysis (ICA), where the goal is to transform the data such that the components become as independent as possible. The second is based on the notion of diagonality of certain characteristic matrices derived from the data. Here the goal is to transform the matrices such that they become as diagonal as possible. In this thesis we study the latter method of approximate joint diagonalization (AJD) to achieve a solution of the BSS problem. After an introduction to the general setting, the thesis provides an overview on particular choices for the set of target matrices that can be used for BSS by joint diagonalization. As the main contribution of the thesis, new algorithms for approximate joint diagonalization of several matrices with non-orthogonal transformations are developed. These newly developed algorithms will be tested on synthetic benchmark datasets and compared to other previous diagonalization algorithms. Applications of the BSS methods to biomedical signal processing are discussed and exemplified with real-life data sets of multi-channel biomagnetic recordings.},
subject = {Signaltrennung},
language = {en}
}
@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}
}