@phdthesis{Kiesel2022,
  author    = {Kiesel, Johannes},
  title     = {Harnessing Web Archives to Tackle Selected Societal Challenges},
  doi       = {10.25643/bauhaus-universitaet.4660},
  url       = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20220622-46602},
  school      = {Bauhaus-Universit{\"a}t Weimar},
  year      = {2022},
  abstract  = {With the growing importance of the World Wide Web, the major challenges our society faces are also increasingly affecting the digital areas of our lives. Some of the associated problems can be addressed by computer science, and some of these specifically by data-driven research. To do so, however, requires to solve open issues related to archive quality and the large volume and variety of the data contained. This dissertation contributes data, algorithms, and concepts towards leveraging the big data and temporal provenance capabilities of web archives to tackle societal challenges. We selected three such challenges that highlight the central issues of archive quality, data volume, and data variety, respectively: (1) For the preservation of digital culture, this thesis investigates and improves the automatic quality assurance of the web page archiving process, as well as the further processing of the resulting archive data for automatic analysis. (2) For the critical assessment of information, this thesis examines large datasets of Wikipedia and news articles and presents new methods for automatically determining quality and bias. (3) For digital security and privacy, this thesis exploits the variety of content on the web to quantify the security of mnemonic passwords and analyzes the privacy-aware re-finding of the various seen content through private web archives.},
  subject      = {Informatik},
  language  = {en}
}
@phdthesis{Weissker,
  author    = {Weißker, Tim},
  title     = {Group Navigation in Multi-User Virtual Reality},
  doi       = {10.25643/bauhaus-universitaet.4530},
  url       = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20211124-45305},
  school      = {Bauhaus-Universit{\"a}t Weimar},
  pages     = {148},
  abstract  = {Multi-user virtual reality systems enable collocated as well as distributed users to perform collaborative activities in immersive virtual environments. A common activity in this context is to move from one location to the next as a group to explore the environment together. The simplest solution to realize these multi-user navigation processes is to provide each participant with a technique for individual navigation. However, this approach entails some potentially undesirable consequences such as the execution of a similar navigation sequence by each participant, a regular need for coordination within the group, and, related to this, the risk of losing each other during the navigation process. To overcome these issues, this thesis performs research on group navigation techniques that move group members together through a virtual environment. The presented work was guided by four overarching research questions that address the quality requirements for group navigation techniques, the differences between collocated and distributed settings, the scalability of group navigation, and the suitability of individual and group navigation for various scenarios. This thesis approaches these questions by introducing a general conceptual framework as well as the specification of central requirements for the design of group navigation techniques. The design, implementation, and evaluation of corresponding group navigation techniques demonstrate the applicability of the proposed framework. As a first step, this thesis presents ideas for the extension of the short-range teleportation metaphor, also termed jumping, for multiple users. It derives general quality requirements for the comprehensibility of the group jumping process and introduces a corresponding technique for two collocated users. The results of two user studies indicate that sickness symptoms are not affected by user roles during group jumping and confirm improved planning accuracy for the navigator, increased spatial awareness for the passenger, and reduced cognitive load for both user roles. Next, this thesis explores the design space of group navigation techniques in distributed virtual environments. It presents a conceptual framework to systematize the design decisions for group navigation techniques based on Tuckman's model of small-group development and introduces the idea of virtual formation adjustments as part of the navigation process. A quantitative user study demonstrates that the corresponding extension of Multi-Ray Jumping for distributed dyads leads to more efficient travel sequences and reduced workload. The results of a qualitative expert review confirm these findings and provide further insights regarding the complementarity of individual and group navigation in distributed virtual environments. Then, this thesis investigates the navigation of larger groups of distributed users in the context of guided museum tours and establishes three central requirements for (scalable) group navigation techniques. These should foster the awareness of ongoing navigation activities as well as facilitate the predictability of their consequences for all group members (Comprehensibility), assist the group with avoiding collisions in the virtual environment (Obstacle Avoidance), and support placing the group in a meaningful spatial formation for the joint observation and discussion of objects (View Optimization). The work suggests a new technique to address these requirements and reports on its evaluation in an initial usability study with groups of five to ten (partially simulated) users. The results indicate easy learnability for navigators and high comprehensibility for passengers. Moreover, they also provide valuable insights for the development of group navigation techniques for even larger groups. Finally, this thesis embeds the previous contributions in a comprehensive literature overview and emphasizes the need to study larger, more heterogeneous, and more diverse group compositions including the related social factors that affect group dynamics. In summary, the four major research contributions of this thesis are as follows: - the framing of group navigation as a specific instance of Tuckman's model of small-group development - the derivation of central requirements for effective group navigation techniques beyond common quality factors known from single-user navigation - the introduction of virtual formation adjustments during group navigation and their integration into concrete group navigation techniques - evidence that appropriate pre-travel information and virtual formation adjustments lead to more efficient travel sequences for groups and lower workloads for both navigators and passengers Overall, the research of this thesis confirms that group navigation techniques are a valuable addition to the portfolio of interaction techniques in multi-user virtual reality systems. The conceptual framework, the derived quality requirements, and the development of novel group navigation techniques provide effective guidance for application developers and inform future research in this area.},
  subject      = {Virtuelle Realit{\"a}t},
  language  = {en}
}
@phdthesis{Bunte,
  author    = {Bunte, Andreas},
  title     = {Entwicklung einer ontologiebasierten Beschreibung zur Erh{\"o}hung des Automatisierungsgrades in der Produktion},
  doi       = {10.25643/bauhaus-universitaet.4315},
  url       = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20201215-43156},
  school      = {Bauhaus-Universit{\"a}t Weimar},
  pages     = {189},
  abstract  = {Die zu beobachtenden k{\"u}rzeren Produktlebenszyklen und eine schnellere Marktdurchdringung von Produkttechnologien erfordern adaptive und leistungsf{\"a}hige Produktionsanlagen. Die Adaptivit{\"a}t erm{\"o}glicht eine Anpassung der Produktionsanlage an neue Produkte, und die Leistungsf{\"a}higkeit der Anlage stellt sicher, dass ausreichend Produkte in kurzer Zeit und zu geringen Kosten hergestellt werden k{\"o}nnen. Durch eine Modularisierung der Produktionsanlage kann die Adaptivit{\"a}t erreicht werden. Jedoch erfordert heutzutage jede Adaption manuellen Aufwand, z.B. zur Anpassung von propriet{\"a}ren Signalen oder zur Anpassung {\"u}bergeordneter Funktionen. Dadurch sinkt die Leistungsf{\"a}higkeit der Anlage. Das Ziel dieser Arbeit ist es, die Interoperabilit{\"a}t in Bezug auf die Informationsverwendung in modularen Produktionsanlagen zu gew{\"a}hrleisten. Dazu werden Informationen durch semantische Modelle beschrieben. Damit wird ein einheitlicher Informationszugriff erm{\"o}glicht, und {\"u}bergeordnete Funktionen erhalten Zugriff auf alle Informationen der Produktionsmodule, unabh{\"a}ngig von dem Typ, dem Hersteller und dem Alter des Moduls. Dadurch entf{\"a}llt der manuelle Aufwand bei Anpassungen des modularen Produktionssystems, wodurch die Leistungsf{\"a}higkeit der Anlage gesteigert und Stillstandszeiten reduziert werden. Nach dem Ermitteln der Anforderungen an einen Modellierungsformalismus wurden potentielle Formalismen mit den Anforderungen abgeglichen. OWL DL stellte sich als geeigneter Formalismus heraus und wurde f{\"u}r die Erstellung des semantischen Modells in dieser Arbeit verwendet. Es wurde exemplarisch ein semantisches Modell f{\"u}r die drei Anwendungsf{\"a}lle Interaktion, Orchestrierung und Diagnose erstellt. Durch einen Vergleich der Modellierungselemente von unterschiedlichen Anwendungsf{\"a}llen wurde die Allgemeing{\"u}ltigkeit des Modells bewertet. Dabei wurde gezeigt, dass die Erreichung eines allgemeinen Modells f{\"u}r technische Anwendungsf{\"a}lle m{\"o}glich ist und lediglich einige Hundert Begriffe ben{\"o}tigt. Zur Evaluierung der erstellten Modelle wurde ein wandlungsf{\"a}higes Produktionssystem der SmartFactoryOWL verwendet, an dem die Anwendungsf{\"a}lle umgesetzt wurden. Dazu wurde eine Laufzeitumgebung erstellt, die die semantischen Modelle der einzelnen Module zu einem Gesamtmodell vereint, Daten aus der Anlage in das Modell {\"u}bertr{\"a}gt und eine Schnittstelle f{\"u}r die Services bereitstellt. Die Services realisieren {\"u}bergeordnete Funktionen und verwenden die Informationen des semantischen Modells. In allen drei Anwendungsf{\"a}llen wurden die semantischen Modelle korrekt zusammengef{\"u}gt und mit den darin enthaltenen Informationen konnte die Aufgabe des jeweiligen Anwendungsfalles ohne zus{\"a}tzlichen manuellen Aufwand gel{\"o}st werden.},
  subject      = {Ontologie},
  language  = {de}
}
@phdthesis{Kunert,
  author    = {Kunert, Andr{\´e}},
  title     = {3D Interaction Techniques in Multi-User Virtual Reality : towards scalable templates and implementation patterns for cooperative interfaces},
  doi       = {10.25643/bauhaus-universitaet.4296},
  url       = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20201204-42962},
  school      = {Bauhaus-Universit{\"a}t Weimar},
  pages     = {147},
  abstract  = {Multi-user projection systems provide a coherent 3D interaction space for multiple co-located users that facilitates mutual awareness, full-body interaction, and the coordination of activities. The users perceive the shared scene from their respective viewpoints and can directly interact with the 3D content. This thesis reports on novel interaction patterns for collaborative 3D interaction for local and distributed user groups based on such multi-user projection environments. A particular focus of our developments lies in the provision of multiple independent interaction territories in our workspaces and their tight integration into collaborative workflows. The motivation for such multi-focus workspaces is grounded in research on social cooperation patterns, specifically in the requirement for supporting phases of loose and tight collaboration and the emergence of dedicated orking territories for private usage and public exchange. We realized independent interaction territories in the form of handheld virtual viewing windows and multiple co-located hardware displays in a joint workspace. They provide independent views of a shared virtual environment and serve as access points for the exploration and manipulation of the 3D content. Their tight integration into our workspace supports fluent transitions between individual work and joint user engagement. The different affordances of various displays in an exemplary workspace consisting of a large 3D wall, a 3D tabletop, and handheld virtual viewing windows, promote different usage scenarios, for instance for views from an egocentric perspective, miniature scene representations, close-up views, or storage and transfer areas. This work shows that this versatile workspace can make the cooperation of multiple people in joint tasks more effective, e.g. by parallelizing activities, distributing subtasks, and providing mutual support. In order to create, manage, and share virtual viewing windows, this thesis presents the interaction technique of Photoportals, a tangible interface based on the metaphor of digital photography. They serve as configurable viewing territories and enable the individual examination of scene details as well as the immediate sharing of the prepared views. Photoportals are specifically designed to complement other interface facets and provide extended functionality for scene navigation, object manipulation, and for the creation of temporal recordings of activities in the virtual scene. A further objective of this work is the realization of a coherent interaction space for direct 3D input across the independent interaction territories in multi-display setups. This requires the simultaneous consideration of user input in several potential interaction windows as well as configurable disambiguation schemes for the implicit selection of distinct interaction contexts. We generalized the required implementation structures into a high-level software pattern and demonstrated its versatility by means of various multi-context 3D interaction tools. Additionally, this work tackles specific problems related to group navigation in multiuser projection systems. Joint navigation of a collocated group of users can lead to unintentional collisions when passing narrow scene sections. In this context, we suggest various solutions that prevent individual collisions during group navigation and discuss their effect on the perceived integrity of the travel group and the 3D scene. For collaboration scenarios involving distributed user groups, we furthermore explored different configurations for joint and individual travel. Last but not least, this thesis provides detailed information and implementation templates for the realization of the proposed interaction techniques and collaborative workspaces in scenegraph-based VR systems. These contributions to the abstraction of specific interaction patterns, such as group navigation and multi-window interaction, facilitate their reuse in other virtual reality systems and their adaptation to further collaborative scenarios.},
  subject      = {Virtuelle Realit{\"a}t},
  language  = {en}
}
@phdthesis{Markert,
  author    = {Markert, Michael},
  title     = {R{\"a}umliche Navigation durch richtungsgebundene Stereofonie},
  doi       = {10.25643/bauhaus-universitaet.4303},
  url       = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20201214-43038},
  school      = {Bauhaus-Universit{\"a}t Weimar},
  pages     = {394},
  abstract  = {Die Verbreitung mobiler Smartphones und besonders deren allgegenw{\"a}rtige Lokalisierungstechnologien ver{\"a}ndern das Navigationsverhalten im Raum nachhaltig. Parallel zur schnell voranschreitenden Entwicklung allt{\"a}glicher Ger{\"a}te, die mitgef{\"u}hrt werden, setzt der {\"U}bergang der bereits l{\"a}nger dauernden Entwicklung von Virtual-Reality-Technik in eine erweiterte und augmentierte Mixed Reality ein. In diesem Spannungsfeld untersucht die vorliegende Arbeit, inwieweit richtungsgebundene und binaural wiedergegebene Stereofonie die menschliche Bewegung im Raum beeinflussen kann und versucht zu er{\"o}rtern, welche Potenziale in der Wiederentdeckung einer relativ lange bekannten Technik liegen. Der Autor hat im Rahmen dieser Arbeit eine binaurale mobile Applikation f{\"u}r richtungsgebundene Stereofonie entwickelt, mit der virtuelle bewegte oder statische Audio-Hotspots im Raum platziert werden k{\"o}nnen. So kann links, rechts oder 30 Meter vor einer Person ein virtueller oder tats{\"a}chlicher Klang im Raum verortet sein. Durch die in Echtzeit berechnete binaurale Wiedergabe der Klangquellen mit einem Stereo-Kopfh{\"o}rer k{\"o}nnen diese r{\"a}umlich verorteten Kl{\"a}nge mit zwei Ohren dreidimensional wahrgenommen werden, {\"a}hnlich dem r{\"a}umlichen Sehen mit zwei Augen. Durch den Einsatz mehrerer lokalisierter Klangquellen als Soundscape entsteht eine augmentierte auditive Realit{\"a}t, die die physische Realit{\"a}t erweitert. Die Position und Navigation des Nutzers wird durch binaurale Lautst{\"a}rkenmodulation (die Lautst{\"a}rke nimmt bei abnehmender Distanz zur Quelle zu) und Stereopanning mit Laufzeitmodulation (die Richtung wird {\"u}ber ein Stereosignal auf beiden Ohren r{\"a}umlich links-rechts-vorne verortet) interaktiv und kybernetisch beeinflusst. Die Nutzer navigieren — durch ihr Interesse an den h{\"o}rbaren virtuellen Klangquellen geleitet — durch einen dynamisch erzeugten, dreidimensionalen akustischen Raum, der gleichzeitig ein virtueller und kybernetischer Raum ist, da die Repr{\"a}sentation der Kl{\"a}nge an die Bewegung und Ausrichtung der Nutzer im Raum angepasst wird. Diese Arbeit untersucht, ob die Bewegung von Menschen durch (virtuelle) Kl{\"a}nge beeinflusst werden kann und wie groß oder messbar dieser Einfluss ist. Dabei k{\"o}nnen nicht alle k{\"u}nstlerischen, architektonischen und philosophischen Fragen im Rahmen der vorliegenden Schrift er{\"o}rtert werden, obwohl sie dennoch als raumtheoretische Fragestellung von Interesse sind. Hauptgegenstand der vorliegenden Arbeit liegt in der Erforschung, ob richtungsgebundene Stereofonie einen relevanten Beitrag zur menschlichen Navigation, haupts{\"a}chlich zu Fuß, in urbanen Gebieten — vorwiegend im Außenraum — leisten kann. Der erste Teil gliedert sich in »Raum und Klang«, es werden raumtheoretische {\"U}berlegungen zur menschlichen Bewegung im Raum, Raumvorstellungen, r{\"a}umliche Kl{\"a}nge und Klangwahrnehmung sowie die Entwicklung stereofoner Apparaturen und Aspekte der Augmented Audio Reality besprochen. Im zweiten Teil werden drei Demonstratoren als Anwendungsszenarien und drei Evaluierungen im Außenraum vorgestellt. Die Tests untersuchen, ob sich das Verfahren zur Navigation f{\"u}r Fußg{\"a}nger eignet und inwieweit eine Einflussnahme auf das Bewegungsverhalten von Nutzern getroffen werden kann. Die Auswertungen der Tests zeigen, dass sich stereofone Kl{\"a}nge grunds{\"a}tzlich als Navigationssystem eignen, da eine große Mehrzahl der Teilnehmer die akustisch markierten Ziele leicht gefunden hat. Ebenso zeigt sich ein klarer Einfluss auf die Bewegungsmuster, allerdings ist dieser abh{\"a}ngig von individuellen Interessen und Vorlieben. Abschließend werden die Ergebnisse der Untersuchungen im Kontext der vorgestellten Theorien diskutiert und die Potenziale stereofoner Anwendungen in einem Ausblick behandelt. Bei der Gestaltung, Erzeugung und Anwendung mobiler Systeme sind unterschiedliche mentale und r{\"a}umliche Modelle und Vorstellungen der Entwickler und Anwender zu beachten. Da eine umfassende transdisziplin{\"a}re Betrachtung klare Begrifflichkeiten erfordert, werden Argumente f{\"u}r ein raumtheoretisches Vokabular diskutiert. Diese sind f{\"u}r einen gestalterischen Einsatz von richtungsgebundener Stereofonie — besonders im Kontext mobiler Navigation durch akustisch augmentierte R{\"a}ume — {\"a}ußerst relevant.},
  subject      = {Raum},
  language  = {de}
}
@phdthesis{Voelske,
  author    = {V{\"o}lske, Michael},
  title     = {Retrieval Enhancements for Task-Based Web Search},
  doi       = {10.25643/bauhaus-universitaet.3942},
  url       = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20190709-39422},
  school      = {Bauhaus-Universit{\"a}t Weimar},
  abstract  = {The task-based view of web search implies that retrieval should take the user perspective into account. Going beyond merely retrieving the most relevant result set for the current query, the retrieval system should aim to surface results that are actually useful to the task that motivated the query. This dissertation explores how retrieval systems can better understand and support their users' tasks from three main angles: First, we study and quantify search engine user behavior during complex writing tasks, and how task success and behavior are associated in such settings. Second, we investigate search engine queries formulated as questions, and explore patterns in a large query log that may help search engines to better support this increasingly prevalent interaction pattern. Third, we propose a novel approach to reranking the search result lists produced by web search engines, taking into account retrieval axioms that formally specify properties of a good ranking.},
  subject      = {Information Retrieval},
  language  = {en}
}
@phdthesis{Bruns2010,
  author    = {Bruns, Erich},
  title     = {Adaptive Image Classification on Mobile Phones},
  doi       = {10.25643/bauhaus-universitaet.1421},
  url       = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20100707-15092},
  school      = {Bauhaus-Universit{\"a}t Weimar},
  year      = {2010},
  abstract  = {The advent of high-performance mobile phones has opened up the opportunity to develop new context-aware applications for everyday life. In particular, applications for context-aware information retrieval in conjunction with image-based object recognition have become a focal area of recent research. In this thesis we introduce an adaptive mobile museum guidance system that allows visitors in a museum to identify exhibits by taking a picture with their mobile phone. Besides approaches to object recognition, we present different adaptation techniques that improve classification performance. After providing a comprehensive background of context-aware mobile information systems in general, we present an on-device object recognition algorithm and show how its classification performance can be improved by capturing multiple images of a single exhibit. To accomplish this, we combine the classification results of the individual pictures and consider the perspective relations among the retrieved database images. In order to identify multiple exhibits in pictures we present an approach that uses the spatial relationships among the objects in images. They make it possible to infer and validate the locations of undetected objects relative to the detected ones and additionally improve classification performance. To cope with environmental influences, we introduce an adaptation technique that establishes ad-hoc wireless networks among the visitors' mobile devices to exchange classification data. This ensures constant classification rates under varying illumination levels and changing object placement. Finally, in addition to localization using RF-technology, we present an adaptation technique that uses user-generated spatio-temporal pathway data for person movement prediction. Based on the history of previously visited exhibits, the algorithm determines possible future locations and incorporates these predictions into the object classification process. This increases classification performance and offers benefits comparable to traditional localization approaches but without the need for additional hardware. Through multiple field studies and laboratory experiments we demonstrate the benefits of each approach and show how they influence the overall classification rate.},
  subject      = {Kontextbezogenes System},
  language  = {en}
}
@phdthesis{Salzmann2010,
  author    = {Salzmann, Holger},
  title     = {Collaboration in Co-located Automotive Applications},
  doi       = {10.25643/bauhaus-universitaet.1422},
  url       = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20100712-15102},
  school      = {Bauhaus-Universit{\"a}t Weimar},
  year      = {2010},
  abstract  = {Virtual reality systems offer substantial potential in supporting decision processes based purely on computer-based representations and simulations. The automotive industry is a prime application domain for such technology, since almost all product parts are available as three-dimensional models. The consideration of ergonomic aspects during assembly tasks, the evaluation of humanmachine interfaces in the car interior, design decision meetings as well as customer presentations serve as but a few examples, wherein the benefit of virtual reality technology is obvious. All these tasks require the involvement of a group of people with different expertises. However, current stereoscopic display systems only provide correct 3D-images for a single user, while other users see a more or less distorted virtual model. This is a major reason why these systems still face limited acceptance in the automotive industry. They need to be operated by experts, who have an advanced understanding of the particular interaction techniques and are aware of the limitations and shortcomings of virtual reality technology. The central idea of this thesis is to investigate the utility of stereoscopic multi-user systems for various stages of the car development process. Such systems provide multiple users with individual and perspectively correct stereoscopic images, which are key features and serve as the premise for the appropriate support of collaborative group processes. The focus of the research is on questions related to various aspects of collaboration in multi-viewer systems such as verbal communication, deictic reference, embodiments and collaborative interaction techniques. The results of this endeavor provide scientific evidence that multi-viewer systems improve the usability of VR-applications for various automotive scenarios, wherein co-located group discussions are necessary. The thesis identifies and discusses the requirements for these scenarios as well as the limitations of applying multi-viewer technology in this context. A particularly important gesture in real-world group discussions is referencing an object by pointing with the hand and the accuracy which can be expected in VR is made evident. A novel two-user seating buck is introduced for the evaluation of ergonomics in a car interior and the requirements on avatar representations for users sitting in a car are identified. Collaborative assembly tasks require high precision. The novel concept of a two-user prop significantly increases the quality of such a simulation in a virtual environment and allows ergonomists to study the strain on workers during an assembly sequence. These findings contribute toward an increased acceptance of VR-technology for collaborative development meetings in the automotive industry and other domains.},
  subject      = {Virtuelle Realit{\"a}t},
  language  = {en}
}
@phdthesis{Gorski2010,
  author    = {Gorski, Michael},
  title     = {Cryptanalysis and Design of Symmetric Primitives},
  doi       = {10.25643/bauhaus-universitaet.1439},
  url       = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20101130-15267},
  school      = {Bauhaus-Universit{\"a}t Weimar},
  year      = {2010},
  abstract  = {Der Schwerpunkt dieser Dissertation liegt in der Analyse und dem Design von Block- chiffren und Hashfunktionen. Die Arbeit beginnt mit einer Einf{\"u}hrung in Techniken zur Kryptoanalyse von Blockchiffren. Wir beschreiben diese Methoden und zeigen wie man daraus neue Techniken entwickeln kann, welche zu staerkeren Angriffen fuehren. Im zweiten Teil der Arbeit stellen wir eine Reihe von Angriffen auf eine Vielzahl von Blockchiffren dar. Wir haben dabei Angriffe auf reduzierte Versionen von ARIA und dem AES entwickelt. Darueber hinaus praesentieren wir im dritten Teil Angriffe auf interne Blockchiffren von Hashfunktionen. Wir entwickeln Angriffe, welche die inter- nen Blockchiffren von Tiger und HAS-160 auf volle Rundenanzahl brechen. Die hier vorgestellten Angriffe sind die ersten dieser Art. Ein Angriff auf eine reduzierte Ver- sion von SHACAL-2 welcher fast keinen Speicherbedarf hat, wird ebenfalls vorgestellt. Der vierte Teil der Arbeit befasst sich mit den Design und der Analyse von kryp- tographischen Hashfunktionen. Wir habe einen Slide Angriff, eine Technik welche aus der Analyse von Blockchiffren bekannt ist, im Kontext von Hashfunktionen zur Anwendung gebracht. Dabei praesentieren wir verschiedene Angriffe auf GRINDAHL und RADIOGATUN. Aufbauend auf den Angriffen des zweiten und dritten Teils dieser Arbeit stellen wir eine neue Hashfunktion vor, welche wir TWISTER nennen. TWISTER wurde fuer den SHA-3 Wettbewerb entwickelt und ist bereits zur ersten Runde angenommen.},
  subject      = {Differentielle Kryptoanalyse},
  language  = {en}
}
@phdthesis{Bauriedel2009,
  author    = {Bauriedel, Christian},
  title     = {Ein computergest{\"u}tztes Modellsystem f{\"u}r die Generierung von st{\"a}dtischen Raumstrukturen},
  doi       = {10.25643/bauhaus-universitaet.1396},
  url       = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20090729-14818},
  school      = {Bauhaus-Universit{\"a}t Weimar},
  year      = {2009},
  abstract  = {Die Arbeit besch{\"a}ftigt sich mit der komplexen Aufgabe Stadtstrukturen mit einem Simulationsmodell im Rechner erzeugen zu k{\"o}nnen. Daf{\"u}r wird ein Vierebenenmodell als Untermodellebene eingef{\"u}hrt, um mit allgemeinen Informationen, Parzellierung, Geb{\"a}uden und Optimierung der Struktur arbeiten zu k{\"o}nnen.},
  subject      = {Stadtstruktur},
  language  = {de}
}