The first-order theory of lexicographic path orderings is undecidable

We show, under some assumption on the signature, that the *This formula not viewable on a Text-Browser* fragment of the theory of any lexicographic path ordering is undecidable. This applies to partial and to total precedences. Our result implies in particular that the simplification rule of ordered completion is undecidable

Verbmobil : translation of face-to-face dialogs

Verbmobil is a long-term project on the translation of spontaneous language in negotiation dialogs. We describe the goals of the project, the chosen discourse domains and the initial project schedule. We discuss some of the distinguishing features of Verbmobil and introduce the notion of translation on demand and variable depth of processing in speech translation. Finally, the role of anytime modules for efficient dialog translation in close to real time is described

The application of two-level morphology to non-concatenative German morphology

In this paper I describe a hybrid system for morphological analysis and synthesis. This system consists of two parts. The treatment of morphonology and non-concatenative morphology is based on the two-level approach proposed by Koskenniemi (1983). For the concatenative part of morphosyntax (i.e. affixation) a grammar based on feature-unification is made use of. Both parts rely on a morph lexicon. Combinations of two-level morphology with feature-based morphosyntactic grammars have already been proposed by several authors (c.f. Bear 1988a, Carson 1988, Görz & Paulus 1988, Schiller & Steffens 1989) to overcome the shortcomings of the continuation-classes originally proposed by Koskenniemi (1983) and Karttunen (1983) for the description of morphosyntax. But up to now no linguistically satisfying solution has been proposed for the treatment of non-concatenative morphology in such a framework. In this paper I describe an extension to the model which will allow for the description of such phenomena. Namely it is proposed to restrict the applicability of two-level rules by providing them with filters in the form of feature structures. It is demonstrated how a well-known problem of German morphology, so-called "Umlautung", can be described in this approach in a linguistically motivated and efficient way

Corporate agents

The logic of belief and intention in situations with multiple agents is increasingly well understood, but current formal approaches appear to face problems in applications where the number of agents greatly exceeds two. We provide an informal development of Corporate Agents, an intensional approximation of individual and group states which treats groups symmetrically with autonomous agents. Corporate Charters, constraints derived from typical patterns of information flow, replace detailed reasoning about the propagation of attitudes in most contexts. The approximation to an ideal logical formulation is not tight, but the model appears to function well in information-poor environments and fails in ways related to characteristic human errors. It may therefore be particularly appropriate to application in the area of natural language discourse

Konzeption einer deklarativen Wissensbasis über recyclingrelevante Materialien

Das Recycling von Produkten und Produktionsreststoffen erlangt als Einflußfaktor für wirtschaftliche Entscheidungsprozesse eine immer größere Bedeutung. Die Integration von recyclingrelevanten Daten in betriebliche Informationsstrukturen sollte in Zukunft durch wissensbasierte Methoden unterstützt werden. Wir stellen Ansätze für eine Wissensbasis zur recyclinggerechten Produkt- und Produktionsplanung vor, und gehen dann genauer auf das grundlegende Modul über Materialien ein. Es wird untersucht, welche Evolutionstechniken sich zur Pflege derartiger Wissensbestände eignen, z.B. zur Validierung vorhandener und Exploration neuer Materialien im Hinblick auf ihre Recycelbarkeit

Using integrated knowledge acquisition to prepare sophisticated expert plans for their re-use in novel situations

Plans which were constructed by human experts and have been repeatedly executed to the complete satisfaction of some customer in a complex real world domain contain very valuable planning knowledge. In order to make this compiled knowledge re-usable for novel situations, a specific integrated knowledge acquisition method has been developed: First, a domain theory is established from documentation materials or texts, which is then used as the foundation for explaining how the plan achieves the planning goal. Secondly, hierarchically structured problem class definitions are obtained from the practitioners\u27 highlevel problem conceptualizations. The descriptions of these problem classes also provide operationality criteria for the various levels in the hierarchy. A skeletal plan is then constructed for each problem class with an explanation-based learning procedure. These skeletal plans consist of a sequence of general plan elements, so that each plan element can be independently refined. The skeletal plan thus accounts for the interactions between the various concrete operations of the plan at a general level. The complexity of the planning problem is thereby factored in a domain-specific way and the compiled knowledge of sophisticated expert plans can be re-used in novel situations

Theoretical consideration of goal recognition aspects for understanding information in business letters

Businesses are drowning in information - paper forms, e-mail, phone-calls and other media do struggle the speed of managers in handling and processing information. Traditional computer systems do not support business flow because of their inflexibility and their lack in understanding information. A sophisticated understanding of the meaning of a business letter requires an understanding of why the sender wrote it. This paper describes some ideas to use goal recognition techniques as one possibility, or method to initiate information understanding. It brings together two areas of cognition: goal recognition and document understanding. To do so, it gives an overview of the application of goal recognition techniques to the discovery of the overall purpose of a letter and a coherent explanation of how the individual sentences are meant to achieve that purpose

The refitting of plans by a human expert

During the course of the development of a Case-Oriented Expert System for situated applications additional cases were needed. The required cases were obtained by having a human expert refit old solutions to new problems and the structural relations between source and target cases were analyzed: A higher degree of reuse of the old cases was found when the expert could apply derivational reasoning and a uniform design rationale (i.e. the solution of the source was generated by the expert himself) than when the expert could only analyze structural relationships (i.e. the source solution was constructed by some one else). Except with very obvious cases, it was also found, that different experts perceive different cases as the most similar source to a given target problem. The results also indicate for user-situated applications of expert systems

Hierarchical skeletal plan refinement : task- and inference structures

This paper presents the task- and inference structure for skeletal plan refinement which was developed for lathe production planning, the application domain of the ARC-TEC project. Two inference structures are discussed: a global inference structure which was developed in the first phase of knowledge acquisition and a more detailed inference structure which builds on the hierarchical organization of the skeletal plans. The described models are evaluated with respect to their cognitive adequacy and their scope of application. The benefits and limitations of the KADS knowledge acquisition methodology are discussed with respect to the development of the two models

Akquisition und Repräsentation von technischem Wissen für Planungsaufgaben im Bereich der Fertigungstechnik

Im Bereich der Fertigungstechnik kann eine Fülle von Planungsaufgaben identifiziert werden, die für eine Bearbeitung mit Methoden der KI geeignet erscheinen. Das Projekt ARC-TEC am DFKI wendet die KADS-Methode zur systematischen Entwicklung von Expertensystemen an und erstellt Tools für alle Phasen dieser Entwicklung. Die Brauchbarkeit der entwickelten Methoden und Tools wird am Beispiel der Erstellung von Arbeitsplänen für die Drehbearbeitung demonstriert. Besonderes Augenmerk gilt dabei der expliziten Repräsentation des konkreten Expertenwissens und der Bearbeitung des gegebenen Problems in einer der Vorgehensweise des Experten möglichst naheliegenden Weise.In the area of production engineering many planning tasks can be found which seem well-suited to be tackled using AI-methodologies. The ARC-TEC project of the DFKI uses the model based KADS approach for a systematic development of expert systems and provides tools to support the different phases of this development. The generation of work plans for manufacturing by turning is used as an example to demonstrate the applicability of the different tools and methodologies. Special focus is upon the explicit representation of the concrete experts knowledge and the problem solving strategy which closely follows the way an expert solves the problem