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Now showing items 71-80 of 93
Preprint
Semantic network analysis of ontologies
(2006)
A key argument for modeling knowledge in ontologies is the easy re-use and re-engineering of the knowledge. However, beside consistency checking, current ontology engineering tools provide only basic functionalities for analyzing ontologies. Since ontologies can be considered as (labeled, directed) graphs, graph analysis techniques are a suitable answer for this need. Graph analysis has been performed by sociologists for over 60 years, and resulted in the vivid research area of Social Network Analysis (SNA). While ...
Preprint
BibSonomy: a social bookmark and publication sharing system
(2006)
Social bookmark tools are rapidly emerging on the Web. In such systems users are setting up lightweight conceptual structures called folksonomies. The reason for their immediate success is the fact that no specific skills are needed for participating. In this paper we specify a formal model for folksonomies and briefly describe our own system BibSonomy, which allows for sharing both bookmarks and publication references in a kind of personal library.
Preprint
Reverse pivoting in conceptual information systems
(2001)
In database marketing, the behavior of customers is analyzed by studying the transactions they have performed. In order to get a global picture of the behavior of a customer, his single transactions have to be composed together. In On-Line Analytical Processing, this operation is known as reverse pivoting. With the ongoing data analysis process, reverse pivoting has to be repeated several times, usually requiring an implementation in SQL. In this paper, we present a construction for conceptual scales for reverse ...
Preprint
Kollaboratives Wissensmanagement
(2006)
Wissensmanagement in zentralisierten Wissensbasen erfordert einen hohen Aufwand für Erstellung und Wartung, und es entspricht nicht immer den Anforderungen der Benutzer. Wir geben in diesem Kapitel einen Überblick über zwei aktuelle Ansätze, die durch kollaboratives Wissensmanagement diese Probleme lösen können. Im Peer-to-Peer-Wissensmanagement unterhalten Benutzer dezentrale Wissensbasen, die dann vernetzt werden können, um andere Benutzer eigene Inhalte nutzen zu lassen. Folksonomies versprechen, die Wissensakquisition ...
Preprint
Trend detection in folksonomies
(2006)
As the number of resources on the web exceeds by far the number of documents one can track, it becomes increasingly difficult to remain up to date on ones own areas of interest. The problem becomes more severe with the increasing fraction of multimedia data, from which it is difficult to extract some conceptual description of their contents. One way to overcome this problem are social bookmark tools, which are rapidly emerging on the web. In such systems, users are setting up lightweight conceptual structures called ...
Dissertation
Design, implementation and application of a generic framework for integrated regional land-use modeling
(2008-02-19)
Land use is a crucial link between human activities and the natural environment and one of the main driving forces of global environmental change. Large parts of the terrestrial land surface are used for agriculture, forestry, settlements and infrastructure. Given the importance of land use, it is essential to understand the multitude of influential factors and resulting land use patterns. An essential methodology to study and quantify such interactions is provided by the adoption of land-use models. By the application ...
Preprint
On the Gap-Complexity of Simple RL-Automata
(2006)
Analysis by reduction is a method used in linguistics for checking the correctness of sentences of natural languages. This method is modelled by restarting automata. All types of restarting automata considered in the literature up to now accept at least the deterministic context-free languages. Here we introduce and study a new type of restarting automaton, the so-called t-RL-automaton, which is an RL-automaton that is rather restricted in that it has a window of size one only, and that it works under a minimal ...
Technischer Report
Genetic Programming meets Model-Driven Development
(2007-07-02)
Genetic programming is known to provide good solutions for many problems like the evolution of network protocols and distributed algorithms. In such cases it is most likely a hardwired module of a design framework that assists the engineer to optimize specific aspects of the system to be developed. It provides its results in a fixed format through an internal interface. In this paper we show how the utility of genetic programming can be increased remarkably by isolating it as a component and integrating it into the ...
Dissertation
CD-Systems of Restarting Automata
(2008-09-10)
Die vorliegende Arbeit behandelt Restartautomaten und Erweiterungen von Restartautomaten.
Restartautomaten sind ein Werkzeug zum Erkennen formaler Sprachen. Sie sind motiviert durch
die linguistische Methode der Analyse durch Reduktion und wurden 1995 von Jancar, Mráz, Plátek und Vogel eingeführt.
Restartautomaten bestehen aus einer endlichen Kontrolle, einem Lese/Schreibfenster fester Größe und einem flexiblen Band. Anfänglich enthält dieses sowohl die Eingabe als auch Bandbegrenzungssymbole.
Die Berechnung eines ...
Diplomarbeit
Unterstützung suboptimaler Regelkreise durch eine zentrale Korrektursteuerung
(2006-04-03)
Evolutionäre Algorithmen werden gerne für Optimierungsaufgaben mit sehr vielen Freiheitsgraden eingesetzt. Eine spezielle Konvergenzeigenschaft, daß nämlich der Rechenaufwand nur mit der Wurzel der Anzahl der Unbekannten steigt, prädestiniert sie dafür. Die evolutionären Algorithmen haben aber auch noch eine weitere interessante Eigenschaft: Von der Zielfunktion wird nur verlangt, daß sie monoton ist - nichts weiter. Speziell wird, im Gegensatz zu gradientenbasierten Verfahren, keinerlei Ableitung von der Zielfunktion ...