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Now showing items 11-20 of 61
Dissertation
Context as a Service
(2013-03-22)
In the vision of Mark Weiser on ubiquitous computing, computers are disappearing from the focus of the users and are seamlessly interacting with other computers and users in order to provide information and services. This shift of computers away from direct computer interaction requires another way of applications to interact without bothering the user. Context is the information which can be used to characterize the situation of persons, locations, or other objects relevant for the applications.
Context-aware ...
Dissertation
Information Exchange and Fusion in Dynamic and Heterogeneous Distributed Environments
(2010-12-10)
Context awareness, dynamic reconfiguration at runtime and heterogeneity are key characteristics of future distributed systems, particularly in ubiquitous and mobile computing scenarios. The main contributions of this dissertation are theoretical as well as architectural concepts facilitating information exchange and fusion in heterogeneous and dynamic distributed environments. Our main focus is on bridging the heterogeneity issues and, at the same time, considering uncertain, imprecise and unreliable sensor information ...
Dissertation
Decision Making for Teams of Mobile Robots
(2016-11-02)
In the past years, we could observe a significant amount of new robotic systems in science, industry, and everyday life. To reduce the complexity of these systems, the industry constructs robots that are designated for the execution of a specific task such as vacuum cleaning, autonomous driving, observation, or transportation operations. As a result, such robotic systems need to combine their capabilities to accomplish complex tasks that exceed the abilities of individual robots. However, to achieve emergent cooperative ...
Dissertation
Managing Quality Properties of Web Service Compositions
(2015-04-28)
Web services from different partners can be combined to applications that realize a more complex business goal. Such applications built as Web service compositions define how interactions between Web services take place in order to implement the business logic. Web service compositions not only have to provide the desired functionality but also have to comply with certain Quality of Service (QoS) levels. Maximizing the users' satisfaction, also reflected as Quality of Experience (QoE), is a primary goal to be achieved ...
Dissertation
Adaptive Real-time Anomaly-based Intrusion Detection using Data Mining and Machine Learning Techniques
(2014-09-15)
Die zunehmende Vernetzung der Informations- und Kommunikationssysteme führt zu einer weiteren Erhöhung der Komplexität und damit auch zu einer weiteren Zunahme von Sicherheitslücken. Klassische Schutzmechanismen wie Firewall-Systeme und Anti-Malware-Lösungen bieten schon lange keinen Schutz mehr vor Eindringversuchen in IT-Infrastrukturen. Als ein sehr wirkungsvolles Instrument zum Schutz gegenüber Cyber-Attacken haben sich hierbei die Intrusion Detection Systeme (IDS) etabliert. Solche Systeme sammeln und analysieren ...
Dissertation
Systems of Parallel Communicating Restarting Automata
(2013-07-31)
In der vorliegenden Dissertation werden Systeme von parallel arbeitenden und miteinander kommunizierenden Restart-Automaten (engl.: systems of parallel communicating restarting automata; abgekürzt PCRA-Systeme) vorgestellt und untersucht. Dabei werden zwei bekannte Konzepte aus den Bereichen Formale Sprachen und Automatentheorie miteinander vescrknüpft: das Modell der Restart-Automaten und die sogenannten PC-Systeme (systems of parallel communicating components).
Ein PCRA-System besteht aus endlich vielen ...
Dissertation
Instant Storyboarding
(2015-11-09)
This thesis aims at empowering software customers with a tool to build software tests them selves, based on a gradual refinement of natural language scenarios into executable visual test models. The process is divided in five steps:
1. First, a natural language parser is used to extract a graph of grammatical relations from the textual scenario descriptions.
2. The resulting graph is transformed into an informal story pattern by interpreting structurization rules based on Fujaba Story Diagrams.
3. While the ...
Dissertation
Model-driven development of sensor network applications with optimization of non-functional constraints
(2016-06-23)
Wireless sensor networks (WSNs) differ from conventional distributed systems in many aspects. The resource limitation of sensor nodes, the ad-hoc communication and topology of the network, coupled with an unpredictable deployment environment are difficult non-functional constraints that must be carefully taken into account when developing software systems for a WSN. Thus, more research needs to be done on designing, implementing and maintaining software for WSNs. This thesis aims to contribute to research being done ...
Dissertation
Relations and Transductions Realized by Restarting Automata
(2013-10-09)
Gegenstand der vorliegenden Arbeit ist die Analyse verschiedener Formalismen zur Berechnung binärer Wortrelationen. Dabei ist die Grundlage aller hier ausgeführten Betrachtungen das Modell der Restart-Automaten, welches 1995 von Jancar et. al. eingeführt wurde. Zum einen wird das bereits für Restart-Automaten bekannte Konzept der input/output- und proper-Relationen weiterführend untersucht, sowie auf Systeme von zwei parallel arbeitenden und miteinander kommunizierenden Restart-Automaten (PC-Systeme) erweitert. Zum ...
Dissertation
Ordered Restarting Automata
(epubli, 2018-07-10)
In der folgenden Arbeit geht es um geordnete Restartautomaten. Restartautomaten sind ein theoretisches Modell, das in der Linguistik bei der Analyse durch Reduktion Verwendung findet. Die geordneten Restartautomaten wurden im Zusammenhang von zweidimensionalen Bildsprachen eingeführt und bilden das zugrundeliegende eindimensionale Modell.
Von diesem eindimensionalen Modell betrachten wir verschiedene Varianten und untersuchen und vergleichen hauptsächlich Sprachklassen und Beschreibungskomplexität. Eine Gemeinsamkeit ...