GPU-based Simulation of Cold Air Flow for Environmental Planning

Simulating the effects of different land-use types regarding flow resistance and cold air production is important for controlling air quality around urban areas. In this paper we present a mathematical model and a simulation method for this problem. This model describes the cold air flow to be composed of two variables. The first is the velocity field which depends on flow resistance and the flow gradient. The second variable is a height field of the cold air which depends on cold air production and advection. To accelerate the simulation and its visualization, it is adapted to run on a GPU(Graphical Processing Unit). Implementing the simulation on fragment shaders makes it possible to combine the height field of the landscape with a color-coded volume rendering of the associated cold-air height. In two passes we compute the cold air height for each time step and render the result to a texture. In a third pass, we render the height field of the landscape using this texure as multi-layered opacity map. urban area forest acre meadow vineyard no data Figure 1: land-use types stimulating cold air production for our simulatio

PAntUDE - an anti-unification algorithm for expressing refined generalizations

In this paper some improvements for the basic algorithm for anti-unification are presented. The standard (basic) algorithm for anti-unification still may give too general answers with respect to the intended use of the result. 'Too general' means obtaining an unwanted answer when instantiating some variables of the antiunification output term. To avoid this, a term sometimes should be generalized by regarding certain (semantic) restrictions. In PAntUDE (partial anti-unification with domains and exlusions) two principal improvements of the basic algorithm were implemented and tested: it can use masks for preventing anti-unification of certain arguments (partial anti-unification); it can also use finite domains for enumerating input-term constants instead of introducing a new (universally quantified) variable, and finite exclusions for specifying forbidden constants (anti-unification with domains and exclusions). (orig.)SIGLEAvailable from TIB Hannover: RR 2041(94-04) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

Using IR techniques for text classification in document analysis

This paper presents the INFOCLAS system applying statistical methods of information retrieval for the classificatioin of German business letters into corresponding message types such as order, offer, enclosure, etc. INFOCLAS is a first step towards the understanding of documents proceeding to a classification-driven extraction of information. The system is composed of two main modules: the central indexer (extraction and weighting of indexing terms) and the classifier (classification of business letters into given types). The system employs several knowledge sources including a letter database, word frequency statistics for German, lists of message type specific words, morphological knowledge as well as the underlying document structure. As output, the system evaluates a set of weighted hypotheses about the type of the actual letter. Classification of documents allow the automatic distribution or archiving of letters and is also an excellent starting point for higher-level document analysis. (orig.)SIGLEAvailable from TIB Hannover: RR 1812(94-19) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

COLLATE - Computational linguistics and language technology for real-world applications Final report

SIGLEAvailable from TIB Hannover: F04B2105 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung und Forschung (BMBF), Bonn (Germany)DEGerman

Uncertainty-valued Horn clauses

There are many forms of uncertainty, each usually again having more than one theoretical model. Therefore, a very flexible kind of uncertainty-valued Horn clauses is introduced in RELFUN in section 1. They have a head, several premises and an uncertainty factor, which represents the uncertainty of the clause. The premises are all 'functional' in the sense that their returned value is again an uncertainty value. These premises and the uncertainty factor of an uncertainty rule become embedded into the arguments of a combination function when translating uncertainty clauses into footed clauses (non-ground, non-deterministic functions in RELFUN, which can then be compiled as usual). The combination function can be modified by the user. It may be a built-in or a user-defined function, either of which may be computed as the value of a higher-order function. In section 2, an application of uncertainty clauses to the uncertain concept of a 'pet holder', according to German law, is described. This and another example are then fully demonstrated in appendix A. Finally, appendix B gives a listing of the complete uncertainty translator in LISP. (orig.)SIGLEAvailable from TIB Hannover: RR 2041(94-03) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Creative problem solving and automated discovery An analysis of psychological and AI research

Since creativity is the ability to produce something novel and unexpected, it has always fascinated people. Consequently, efforts have been made in AI to invent creative computer programs. At the same time much effort was spent in psychology to analyze the foundations of human creative behaviour. However, until now efforts in AI to produce creative programs have been largely independent from psychological research. In this study, we try to combine both fields of research. First, we give a short summary of the main results of psychological research on creativity. Based on these results we propose a model of the creative process that emphasizes its information processing aspects. Then we describe AI approaches to the implementation of the various components of this model and contrast them with the results of psychological research. As a result we will not only reveal weaknesses of current AI systems hindering them in achieving creativity, but we will also make plausible suggestions - based on psychological research - for overcoming these weaknesses. (orig.)SIGLEAvailable from TIB Hannover: RR 2041(95-04) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Knowledge bases in the World Wide Web: a challenge for logic programming

Regarding the World Wide Web, knowledge bases can be categorized between (HTML-)documents and (SQL-)databases. In order to standardize them, the use of Horn logic for Web publications is proposed. The design of a Web search engine for processing distributed Horn-logic knowledge bases is sketched. Some of the research issues to be solved are elaborated from the perspective of (parallel, modular) logic programming. Possible Inter- and intranet applications are discussed. An LP-community effort for building up Horn-logic knowledge bases in the Web is encouraged. (orig.)SIGLEAvailable from TIB Hannover: RR 2041(96-02) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman