In this paper we propose to apply hierarchical graphs to indoor navigation. The intended purpose is to guide humans in large public buildings and assist them in wayfinding. We start by formally defining hierarchical graphs and explaining the particular benefits of this approach. In the main part, we suggest an algorithm to automatically construct such a multi-level hierarchy from floor plans. The algorithm is guided by the idea to exploit domain-specific characteristics of indoor environments. Besides this, two particular problems are addressed: first, how to incorporate three-dimensional elements in the hierarchy, and second, the need for extending the hierarchy at complex geometrical regions with implicit decision points. An extended version of this paper is also available [1].

In the domain of supervisory control and data acquisition (SCADA), significant challenges reside in the variety of proprietary interfaces and protocols which accompany the components and devices provided by different manufacturers. The Facility Control Markup Language (FCML) is designed to provide standardized and uniform access to different devices which usually only adhere to proprietary interfaces and protocols. As an application of the Extensible Markup Language (XML), FCML is designed as an open and extensible standard which can easily be adapted and extended to include requirements of future applications and devices. The subjacent vision includes the conjecture that Web-based SCADA systems are very promising for a wide range of SCADA applications, for reasons of modularity and ease of deployment.

This article describes a particular use of ontologies for visualising maps in a browser window. Geographic data are represented as instances of concepts in an ontology of transportation networks which was designed in close relation to GDF. These data are transformed into SVG, whereas the transformation is specified symbolically as instances of a transformation ontology. This approach is extremely flexible and easily extendible to include all kinds of information in the generated maps. The basic implementation technique is to use classes and instances of ontologies in an intelligent way. This article is an abbreviated version of the research report [12].

Time intervals like "tonight", which are usually not very precise, can be modeled as fuzzy sets. But this causes the problem that the relations between points and intervals and between two intervals, which are usually very trivial, become very complex when the intervals are fuzzy sets. Moreover, there are many different possibilities to define such relations. In this paper a very flexible operator-based approach to point-interval and interval-interval relations is proposed, where the intervals are fuzzy time intervals over the real numbers. The relations yield non-trivial fuzzy values even if the intervals are crisp. As an example for an application, consider a database with, say, a cinema timetable, and you query the timetable give me all performances ending before midnight. The usual "before" relation will exclude the performances ending a second after midnight. With the fuzzy before relation you can get instead of a sharp drop to 0 at midnight decreasing fuzzy values after midnight, and these can be used to order the results of the query. The intervals and relations are implemented in the Fu-TIRe library (Fuzzy Time intervals and Relations). FuTIRe is an open source C++ library.

The key notion for modelling calendar systems as well as many periodic events, for example the seasons, is the notion of a partitioning of the real numbers. A partitioning of R splits the time axis into a finite or infinite sequence of intervals. Basic time units like seconds, minutes, hours, days, weeks, months, years etc. can all be represented by finite partitionings of R. There are a lot of other temporal notions which can be modelled as partitions either: the seasons, the ecclesiastical calendars, financial years, semesters at universities, the sequence of sunrises and sunsets, the sequence of the tides, the sequence of school holidays etc. In this paper, a formalization of periodic temporal notions by means of partitionings R is presented.

Normal modal logics can be defined axiomatically as Hilbert systems, or semantically in terms of Kripke's possible worlds and accessibility relations. Unfortunately there are Hilbert axioms which do not have corresponding first-order properties for the accessibility relation. For these logics the standard semantics-based theorem proving techniques, in particular, the relational translation into first-order predicate logic, do not work. There is an alternative translation, the so-called functional translation, in which the accessibility relations are replaced by certain terms which intuitively can be seen as functions mapping worlds to accessible worlds. In this paper we show that from a certain point of view this functional language is more expressive than the relational language, and that certain second-order frame properties can be mapped to first-order formulae expressed in the functional language. Moreover, we show how these formulae can be computed automatically from the Hilbert axioms. This extends the applicability of the functional translation method.

A general framework for translating logical formulae from one logic into another logic is presented. The framework is instantiated with two different approaches to translating modal logic formulae into predicate logic. The first one, the well known ‘relational’ translation makes the modal logic‘s possible worlds structure explicit by introducing a distinguished predicate symbol to represent the accessibility relation. In the second approach, the ‘functional’ translation method, paths in the possible worlds structure are represented by compositions of functions which map worlds to accessible worlds. On the syntactic level this means that every flexible symbol is parametrized with particular terms denoting whole paths from the initial world to the actual world. The ‘target logic’ for the translation is a first-order many-sorted logic with built in equality. Therefore the ‘source logic’ may also be first-order function symbols are allowed. Furthermore flexible function symbols are allowed. The modal operators may be parametrized with arbitrary terms and particular properties of the accessibility relation may be specified within the logic itself.