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Self-localization in unknown environments respectively correlation of current and former impressions of the world is an essential ability for most mobile robots. The method,proposed in this article is the construction of a qualitative, topological world model as a basis for self-localization. As a central aspect the reliability regarding error-tolerance and stability will be emphasized. The proposed techniques demand very low constraints for the kind and quality of the employed sensors as well as for the kinematic precisionof the utilized mobile platform. Hard real-time constraints can be handled due to the low computational complexity. The principal discussions are supported by real-world experiments with the mobile robot.
World models for mobile robots as introduced in many projects, are mostly redundant regarding similar situations detected in different places. The present paper proposes a method for dynamic generation of a minimal world model based on these redundancies. The technique is an extention of the qualitative topologic world modelling methods. As a central aspect the reliability regarding errortolerance and stability will be emphasized. The proposed technique demands very low constraints on the kind and quality of the employed sensors as well as for the kinematic precision of the utilized mobile platform. Hard realtime constraints can be handled due to the low computational complexity. The principal discussions are supported by real-world experiments with the mobile robot "
We study the combination of the following already known ideas for showing confluence ofunconditional or conditional term rewriting systems into practically more useful confluence criteria forconditional systems: Our syntactic separation into constructor and non-constructor symbols, Huet's intro-duction and Toyama's generalization of parallel closedness for non-noetherian unconditional systems, theuse of shallow confluence for proving confluence of noetherian and non-noetherian conditional systems, theidea that certain kinds of limited confluence can be assumed for checking the fulfilledness or infeasibilityof the conditions of conditional critical pairs, and the idea that (when termination is given) only primesuperpositions have to be considered and certain normalization restrictions can be applied for the sub-stitutions fulfilling the conditions of conditional critical pairs. Besides combining and improving alreadyknown methods, we present the following new ideas and results: We strengthen the criterion for overlayjoinable noetherian systems, and, by using the expressiveness of our syntactic separation into constructorand non-constructor symbols, we are able to present criteria for level confluence that are not criteria forshallow confluence actually and also able to weaken the severe requirement of normality (stiffened withleft-linearity) in the criteria for shallow confluence of noetherian and non-noetherian conditional systems tothe easily satisfied requirement of quasi-normality. Finally, the whole paper also gives a practically usefuloverview of the syntactic means for showing confluence of conditional term rewriting systems.
In diesem Artikel diskutieren wir Anforderungen aus der Kreditwürdigkeitsprüfung und ihre Erfüllung mit Hilfe der Technik des fallbasierten Schliessens. Innerhalb eines allgemeinen Ansatzes zur fallbasierten Systementwicklung wird ein Lernverfahren zur Optimierung von Entscheidungskosten ausführlich beschrieben. Dieses Verfahren wird, auf der Basis realer Kundendaten, mit dem fallbasierten Entwicklungswerkzeug INRECA empirisch bewertet. Die Voraussetzungen für den Einsatz fallbasierter Systeme zur Kreditwürdigkeitsprüfung werden abschliessend dargestellt und ihre Nüt zlichkeit diskutiert.
A way to derive consistently kinetic models for vehicular traffic from microscopic follow the leader models is presented. The obtained class of kinetic equations is investigated. Explicit examples for kinetic models are developed with a particular emphasis on obtaining models, that give realistic results. For space homogeneous traffic flow situations numerical examples are given including stationary distributions and fundamental diagrams.
Im Rahmen dieser Arbeit beschreiben wir die wesentlichen Merkmale der CAPlan-Architektur, die die interaktive Bearbeitung von Planungsproblemen ermöglichen. Anhand des SNLP-Algorithmus, der der Architektur zugrunde liegt, werden die im Laufe eines Planungsprozesses auftretenden Entscheidungspunkte charakterisiert. Mit Hilfe von frei definierbaren Kontrollkomponenten kann das Verhalten an diesen Entscheidungspunkte festgelegt werden, wodurch eine flexible Steuerung des Planungsprozesses ermöglicht wird. Planungsziele und -entscheidungen werden in einem gerichteten azyklischen Graphen verwaltet, der ihre kausalen Abhängigkeiten widerspiegelt. Im Gegensatz zu einem Stack, der typischerweise zur Verwaltung von Entscheidungen eingesetzt wird, erlaubt die graphbasierte Repräsentation die flexible Rücknahme einer Entscheidung, ohne alle zeitlich danach getroffenen Entscheidungen ebenfalls zurücknehmen zu müssen.
In dieser Arbeit wird die Entwicklung eines Werkzeugs dargestellt, mit des-sen Hilfe die Analyse von Feature-Interaktionen in Intelligenten Netzwerkenunterstützt wird. Es basiert auf der formalen Beschreibungstechnik Estelle, wo-bei durch einen speziellen Spezifikationsstil Feature-Interaktionen anhand vonbestimmten Wechselwirkungen zwischen Transitionen verschiedener Features(u.a. Indeterminismus) erkannt werden können. Das Ziel ist dabei die statischeErkennung und Protokollierung dieser Wechselwirkungen sowie die Entfernungvon nicht ausführbaren Transitionen zur Laufzeitoptimierung.Dazu werden zunächst die theoretischen Möglichkeiten zur Erkennung dieserWechselwirkungen untersucht. Danach werden anhand der Implementierung desAnalysewerkzeugs die eingesetzten Methoden und Algorithmen dargestellt undschließlich der Einsatz des Werkzeugs erläutert, das auf dem Estelle-Compiler PET basiert.
Second Order Scheme for the Spatially Homogeneous Boltzmann Equation with Maxwellian Molecules
(1995)
In the standard approach, particle methods for the Boltzmann equation are obtained using an explicit time discretization of the spatially homogeneous Boltzmann equation. This kind of discretization leads to a restriction of the discretization parameter as well as on the differential cross section in the case of the general Boltzmann equation. Recently, it was shown, how to construct an implicit particle scheme for the Boltzmann equation with Maxwellian molecules. The present paper combines both approaches using a linear combination of explicit and implicit discretizations. It is shown that the new method leads to a second order particle method, when using an equiweighting of explicit and implicit discretization.
Numerical Simulation of the Stationary One-Dimensional Boltzmann Equation by Particle Methods
(1995)
The paper presents a numerical simulation technique - based on the well-known particle methods - for the stationary, one-dimensional Boltzmann equation for Maxwellian molecules. In contrast to the standard splitting methods, where one works with the instationary equation, the current approach simulates the direct solution of the stationary problem. The model problem investigated is the heat transfer between two parallel plates in the rarefied gas regime. An iteration process is introduced which leads to the stationary solution of the exact - space discretized - Boltzmann equation, in the sense of weak convergence.