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    Graphtransformation mit Ontologien
    In this document a new approach of graphtransformation is shown, which uses ontology reasoning within the graphtransformation process. With this approach it is possible to reduce the number of graphtransfotmation rules significant, according to the usecase. Further more this approach allows the usage of infinitive sets of edge markers within graphs and rules.
    Dissertation
      231  137
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    Kennzahlenbasierte Steuerung, Koordination und Aktionsplanung in Multiagentensystemen
    To be of practical use, the implementation of flexible and modular agent-based cyber-physical systems (CPS) for real-world autonomous control applications in Industry 4.0 oftentimes requires the domain-specific software agents to adhere to the organization's overall qualitative and quantitative business goals, usually expressed in terms of numeric key performance indicators (KPI). In this thesis, a general software framework for multi-agent systems (MAS) and CPS is developed that facilitates the integration and configuration of KPI-related objectives into the agents' individual decision processes. It allows the user of an agent system to define new KPIs and associated multi-criteria goals and supports inter-agent coordination as well as detailed KPI-based action planning, all at runtime of the MAS. The domain-independent components of the proposed KPI framework are implemented as a Java programming library and evaluated in a simulated production planning and control scenario.
    Dissertation
      655  695
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    Relevanzbasierte Informationsbeschaffung für die informierte Entscheidungsfindung intelligenter Agenten
    This dissertation introduces relevance-based information acquisition for intelligent software agents based on Howard s information value theory and decision networks. Active information acquisition is crucial in domains with partial observability in order to establish situation awareness of autonomous systems for deliberate decisions. The new semi-myopic approach addresses the complexity challenge of decision-theoretic relevance computation by reducing the set of variables to be evaluated in the first place. Links in a decision network encode stochastic dependencies of variables. Through utility dependency analysis using Pearl s d-separation criterion, the set of relevant variables can be efficiently reduced to a proven minimum without actually computing information value. In addition to an implementation with detailed runtime performance analysis, the applicability of the approach is shown in the domain of intelligent logistics control.
    Dissertation
      723  418
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    Temporal Pattern Mining in Dynamic Environments
    In this work an approach is presented which applies unsupervised symbolic learning to a qualitative abstraction of dynamic scenes in order to create frequent temporal patterns and prediction rules. Having in mind rather complex situations with different objects of various types and relations and temporal interrelations of actions and events, the approach provides means to mine complex temporal patterns taking into account these aspects. It is an extension of the association rule mining algorithm Apriori and combines ideas from relational as well as sequential association rule mining approaches. Temporal interrelations between predicates of patterns are represented qualitatively by interval relations as, e.g., introduced by Allen and Freksa. Additionally, variable unification allows to connect variables of (different) predicates in a complex pattern in order to deal with relational data. As a third aspect, concept restrictions are learned for variables of a pattern.
    Dissertation
      463  250
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    Interactive Multiagent Adaptation of Individual Classification Models for Decision Support
    An essential prerequisite for informed decision-making of intelligent agents is direct access to empirical knowledge for situation assessment. This contribution introduces an agent-oriented knowledge management framework for learning agents facing impediments in self-contained acquisition of classification models. The framework enables the emergence of dynamic knowledge networks among benevolent agents forming a community of practice in open multiagent systems. Agents in an advisee role are enabled to pinpoint learning impediments in terms of critical training cases and to engage in a goal-directed discourse with an advisor panel to overcome identified issues. The advisors provide arguments supporting and hence explaining those critical cases. Using such input as additional background knowledge, advisees can adapt their models in iterative relearning organized as a search through model space. An extensive empirical evaluation in two real-world domains validates the presented approach.
    Dissertation
      431  332
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    Dynamisch adaptive Planung individualisierter Touren
    Living in a dynamic and mobile environment being "always on" and "always connected", surrounded by smart devices and intelligent sensors, makes the vision of "ambient assisted living" in everyday life appear desirable and feasible. WebServices and the Semantic Web provide the technical means to find and use virtually offered relevant every day services pursuing the vision of developing personalized service-roadmaps. With "personal information environments" (PIE) Isbell and Pierce bridge the gap between virtual and physical worlds. This dissertation proposes dynamic adaptive planning of individualized tours as part of a PIE, an augmented reality connected to the real world with the need to navigate therein. It shows itself as alternative for navigating through a vast variety of physical signs providing unfiltered information for everyone. Introducing Frankfurt Airport as one representative of the problem domain clarifies the multi-dimensional orientation problem in dynamic environments. This formally corresponds to solving instances of Trip-Planning-Problems as has been outlined by Godard. Thus the very subject of this work is adaptive tour planning, which yields optimal personalized configuration of services and at the same time a spatially optimized order of services - an optimal tour. One the one hand, the complexity of the problem results from the combination of configuration and tour planning. On the other hand, it is due to the task of continual replanning in dynamic environments. In the first main part of this dissertation a new planning method has been developed, that computes personalized tours under time constraints and optimizes tours for maximum use and with respect to spatial criteria like locality and proximity. A hierarchical method consistently expands minimal tours and traces down the task to navigation planning between areas and configuration planning inside areas. The method plans minimal consistent tours for mandatory stages instantiating plan schemata taking the user context into account and iteratively extends these tours by areas of maximum use. It is shown that the method reduces the exponential planning problem to computationally feasible parts. Further on, for these parts an optimal and exact solution for the Trip-Planning-Problem is provided. Correctness and the computational complexity of methods and algorithms are proved.Spatial prerequisites - the building and route model - are also provided as a service and user model.In the second main part of this dissertation a dynamic and adaptive planning method has been developed, which supports users executing their tour plans and intervenes as soon as the plan execution appears to fail or may be optimized because of improving preconditions. The method integrates adhoc appearing, probably more relevant services into an existing plan, detects increasing or decreasing time quota during execution and adapts a plan to altering preconditions. Proactive and reactive plan monitoring strategies are introduced that continuously control preconditions during execution and act in advance with local corrections in order to defer expensive replanning tasks. In case of a user rejects a local correction, it is shown how replanning can be reduced to the incremental planning method introduced in the first main part. Comparing the results of the planning and replanning method of this dissertation with the results of an exact method shows that the method of planning maximum areas yields near optimal solutions and better solutions as far as the spatial optimization criteria are concerned.
    Dissertation
      278  200
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    Ein deformationsinvarianter Point-of-Interest-Detektor
    Interest point detectors are a common processing step in low-level computer vision. Current interest point detectors exhibit invariance against rotation, scaling, and affine twodimensional transformations. The thesis presents a new algorithm for interest point detection that is invariant against a larger set of transformations, i.e., deformations.
    Dissertation
      330  119
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    Human-Computer Interfaces for Wearable Computers: A Systematic Approach to Development and Evaluation
    The research presented in this thesis examines user interfaces for wearable computers.Wearable computers are a special kind of mobile computers that can be worn on the body. Furthermore, they integrate themselves even more seamlessly into different activities than a mobile phone or a personal digital assistant can.The thesis investigates the development and evaluation of user interfaces for wearable computers. In particular, it presents fundamental research results as well as supporting software tools for wearable user interface development. The main contributions of the thesis are a new evaluation method for user interfaces of wearable computers and a model-driven software toolkit to ease interface development for application developers with limited human-computer interaction knowledge.The research presented in this thesis motivates and validates the research hypothesis that user interfaces for wearable computers are inherently different to stationary desktop interfaces as well as mobile computer interfaces and, therefore, have to be designed differently to make them usable without being a burden for humans.
    Dissertation
      582  175
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    Automatic Classification of Seafloor Image Data by Geospatial Texture Descriptors
    A novel approach for automatic context-sensitive classification of spatially distributed image data is introduced. The proposed method targets applications of seafloor habitat mapping but is generally not limited to this domain or use case. Spatial context information is incorporated in a two-stage classification process, where in the second step a new descriptor for patterns of feature class occurrence according to a generically defined classification scheme is applied. The method is based on supervised machine learning, where numerous state-of-the-art approaches are applicable. The descriptor computation originates from texture analysis in digital image processing. Patterns of feature class occurrence are perceived as a texture-like phenomenon and the descriptors are therefore denoted by Geospatial Texture Descriptors. The proposed method was extensively validated based on a set of more than 4000 georeferenced video mosaics acquired at the Haakon Mosby Mud Volcano north-west of Norway recorded during cruise ARK XIX3b of the German research vessel Polarstern. The underlying classification scheme was derived from a scheme developed for manual annotation of the same dataset applied in the course of Jerosch [2006]. Features of interest are related to methane discharge at mud volcanoes, which are considered a significant source of methane emission. In the experimental evaluation, based on the prepared training and test data, a major improvement of the classification precision compared to local classification as well as classification based on the raw data from the local spatial context was achieved by the application of the proposed method. The classification precision was particularly improved for rarely occurring classes. In a further comparison with annotated data available from Jerosch [2006] the regional setting of the investigation area obtained by the application of the proposed method was found almost equivalent to the results of an experienced scientist.
    Dissertation
      356  148
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    Von persönlicher Schutzbekleidung zum mobilen Schutzassistenzsystem
    Miniaturized and embedded computers open new prospects for Personal Protective Equipment (PPE). PPE will recognize context and react on environmental hazards in an autonomous way in the future. Networked components may predict dangerous situations. These complex systems demand a new participatory design process because the new protective functions have to adjust between user and automated technique for practical use. This PhD thesis deals with the user-oriented development process for these new ambient assisted protection systems. A specific workflow follows the process-oriented and networked character of the new mobile protection system. In addition designated design attributes motivate the need of clothing related solutions.
    Dissertation
      307  172