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

a mobile device acting as a surrogate for the attention of a user. By tracking
this small area, it can be reconstructed what a user has read. With this approach,
studies are made which show possibilities of usage of such a tool. Also a
prototype of an analysis-portal was created that can be used to analyze the
recorded data. This tool was used to analyze the data from a study done with
students of the course Applied Web Data Extraction and Integration. Metrics
and indicators for web usability are identified that are not available with
traditional 'inter-page-level' approaches like Google Analytics focusing on the
navigation path between web pages. The analysis shows how people behave
differently when accessing a desktop or mobile version of a website with their
smartphone and which differences and similarities can be found when comparing
different websites of one domain to each other. Some key performance
indicators are theoretically discussed and some were implemented and their
results are shown.
Arbeitsbereich Knowledge Based Systems
Shqiponja Ahmetaj
Planning in Graph Databases under Description Logic Constraints
Studium: Masterstudium DDP Computational Logic (Erasmus-Mundus)
BetreuerIn: O.Univ.Prof. Dr. Thomas Eiter
In this thesis, we propose a framework for planning in graph databases. To the
best of our knowledge, this is the first attempt to formally define planning in
such setting. We use an expressive action language that is already defined by
an earlier work. This language is expressed through a DL that has the feature to
introduce new values to the data. Graph databases are seen as finite DL
interpretations. We identify some interesting reasoning tasks, relevant for the
setting we consider. The standard one is plan-existence, which corresponds in
trying to find a plan for a given instance of a planning problem. We investigate
two variants of the problem. The difference between them is that in one of
them we do not allow the transactions to introduce fresh constants. We prove
that deciding plan-existence for the variation without fresh constants is PSpacecomplete.
After applying several syntactic restrictions, we are able to determine
NlogSpace and NP-hard cases. We are also able to provide several polynomial
algorithms for some other cases. In addition, to get some insights to
the relationship between our formalism and STRIPS, which is a classical approach
to planning, we investigate whether planning in our setting can be
reduced to STRIPS. We show that such encoding is possible under some
syntactical restrictions. In this way, STRIPS planners can be exploited to solve
our planning problem. Furthermore, we study the variation, where the transactions
are allowed to introduce fresh constants. Intuitively, this makes
planning more involved. We are able to single out some cases in this setting
that can be reduced to planning without fresh constants. In this way we prove
that those cases are in PSpace.
37