PhD Theses

Ant Algorithms for Self-Organization in Social Networks

This work has been finished in May 2007. Peer-to-peer networks and folksonomies are like living organisms, ever growing and changing as time goes on. This thesis addresses the applicability of algorithms derived from the self-organizing and emergent behavior observed from ant colonies to these complex networks for two specific purposes, namely (1) content-based search in unstructured peer-to- peer networks, and (2) the extraction of adaptive user profiles from folksonomies.

High Performance Computing in Finance - On the Parallel Implementation of Pricing and Optimization Models

This work has been finished in May 2006. High Performance Computing is useful in the field of finance for solving problems which are defined on models of financial variables in the form of sequences of scenarios along with their realization probabilities.

Testing of UML Activity Diagrams

In model-driven development, modeling languages provide the means for software development on a higher level of abstraction than traditional general purpose languages. However, compared to general purpose languages, these modeling languages often lack the proper tool support, such as tools for debugging and testing.

REA-DSL: Business Model Driven Data Engineering

This work has been finished in June 2012. Accounting Information Systems (AIS) are essential for companies not only to record and track what events are happening or what events have happened in the past, they are also one of the most important tools for management to predict the financial future of a firm and take according actions.

Self-Organization of Software Libraries: An Artificial Neural Network Approach

This work has been finished in November 1994.

Adaptable Model Versioning based on Model Transformation By Demonstration

This work has been finished in December 2011. Model-driven engineering (MDE) is evermore adopted in academia and industry for being a new paradigm helping software developers to cope with the ever increasing complexity of software systems being developed.

Business Documents for Inter-Organisational Business Processes

This work has been finished in December 2009. Automated business-to-business (B2B) interactions between companies are constantly superseding old paper-based processes. This automation of inter-organizational processes requires a two-fold agreement between the participating business partners.

Defining Executable Modeling Languages with fUML

This work has been finished in December 2014. Model-driven engineering (MDE) is a software development paradigm aiming to cope with the growing complexity of software systems by raising the level of abstraction.

Conceptual Design of Active Object-Oriented Databases

This work has been finished in September 1997. Business rules are statements about business policies and can be formulated according to the event-condition-action structure of rules provided by active database systems, which allow to react to predefined situations by performing an operation if a certain condition is satisfied when the event occurs.

Monitoring von verteilten Systemen

This work has been finished in June 2000. Enhancements to computer systems and networking technologies have lead to an increasing decentralization of services and data which implies the usage of common resources (e.