Abstract-Band - Fakultät für Informatik, TU Wien - Technische ...

of the domain, is expressed in Lana, a meta-language for annotating answerset
programs. Based on the signature in Lana, the programmer proceeds to
develop ASP encodings. After computing the answer sets of the answer-set
program, the user is able to visualise the problem solutions by means of UML
object diagrams. Violations of constraints in the solutions can be seen either
by checking for certain error-indicating atoms in answer sets or can be
visualised directly in the graphical representation of the solution.
Oleksandr Stashuk
Integrating Constraint Programming into Answer Set Programming
Studium: Masterstudium DDP Computational Logic (Erasmus-Mundus)
BetreuerIn: O.Univ.Prof. Dr. Thomas Eiter
Many declarative problems exploit hard computational nature that need to be
evaluated effectively. Examples of such problems are task scheduling,
optimization problems, database transaction management. This thesis presents
a hybrid constraint answer-set programming solver that provides a modeling
language and solving capabilities of Answer-Set Programming (ASP) and
special relations over variables called constraints from area of Constraint
Programming (CP). The proposed framework provides a custom syntax for
supporting constraint and answer-set constructions and in addition it provides
a support for a special type of global constraints. We then show how such
programs can be transformed to HEX programs with external atoms and
evaluated. Several formal properties of such transformation are provided. The
thesis provides several optimizations for the original approach. The first
improvement relies on reducing the size of the transformed program. This is
based on the observation of the redundancy in some of the translated rules.
This translation reduction does not affect answer sets of the programs. Another
optimization is related to the program evaluation. The key idea is to find the
small irreducible inconsistent set of constraints and add it as a nogood to the
program. This way we will introduce user defined learning for the program. We
also show that the learning functions for HEX programs based on these
algorithms are correct. This thesis additionally provides the implementation of
such approach as a plugin for dlvhex system. We show the plugin architecture,
ideas of the implementation and describe required algorithms. We describe
how main components, namely CASP converter, rewriter, external atom
evaluation and learning can be implemented.
Simon Steyskal
Towards an Alternative Approach for Combining Ontology Matchers
Studium: Masterstudium Software Engineering & Internet Computing
BetreuerIn: Privatdoz. Dr. Axel Polleres
The existence of a standardized ontology alignment format promoted by the
Ontology Alignment Evaluation Initiative (OAEI) potentially enables different
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