A Complete and Recursive Feature Theory

Various feature descriptions are being employed in logic programming languages and constrained-based grammar formalisms. The common notational primitive of these descriptions are functional attributes called features. The descriptions considered in this paper are the possibly quantified first-order formulae obtained from a signature of binary and unary predicates called features and sorts, respectively. We establish a first-order theory FT by means of three axiom schemes, show its completeness, and construct three elementarily equivalent models. One of the models consists of so-called feature graphs, a data structure common in computational linguistics. The other two models consist of so-called feature trees, a record-like data structure generalizing the trees corresponding to first-order terms. Our completeness proof exhibits a terminating simplification system deciding validity and satisfiability of possibly quantified feature descriptions.Comment: Short version appeared in the 1992 Annual Meeting of the Association for Computational Linguistic

Concept logics

Concept languages (as used in BACK, KL-ONE, KRYPTON, LOOM) are employed as knowledge representation formalisms in Artificial Intelligence. Their main purpose is to represent the generic concepts and the taxonomical hierarchies of the domain to be modeled. This paper addresses the combination of the fast taxonomical reasoning algorithms (e.g. subsumption, the classifier etc.) that come with these languages and reasoning in first order predicate logic. The interface between these two different modes of reasoning is accomplished by a new rule of inference, called constrained resolution. Correctness, completeness as well as the decidability of the constraints (in a restricted constraint language) are shown

Parameterized abstractions used for proof-planning

In order to cope with large case studies arising from the application of formal methods in an industrial setting, this paper presents new techniques to support hierarchical proof planning. Following the paradigm of difference reduction, proofs are obtained by removing syntactical differences between parts of the formula to be proven step by step. To guide this manipulation we introduce dynamic abstractions of terms. These abstractions are parameterized by the individual goals of the manipulation and are especially designed to ease the proof search based on heuristics. The hierarchical approach and thus the decomposition of the original goal into several subgoals enables the use of different abstractions or different parameters of an abstraction within the proof search. In this paper we will present one of these dynamic abstractions together with heuristics to guide the proof search in the abstract space

Methodological Comparison of Agent Models

Hybrid agent architectures comprise the radical change of paradigms in AI over the past decades by reconciling the different styles of reactive, deliberative, even social systems. They have been successfully applied to a range of complex realworld domains. Due to their originally informal background, a verification of design goals in derived implementations, theoretical foundations, and a detailed comparison with other agent models have not yet been obvious. The present work proposes a formal methodology to bridge the gap between theoretical and practical aspects especially of hybrid designs, such as the layered InteRRaP. The employed, connected stages of specification, i.e., architecture, computational model, theory, proof calculus, and implementation, also provide a yet unique framework for comparing heterogeneous agent models including unified and logic-based ones. Based on recent work on InteRRaP, we demonstrate that this methodology allows to compare state-of-the-art designs from rob..

The Matrix Auction: A Mechanism for the Market-Based Coordination of Enterprise Networks

We argue that a network of shipping companies, that cooperatively executes transportation tasks, can be viewed as a special instance of a virtual enterprise. We propose the matrix auction as an efficient, incentive compatible allocation mechanism for virtual transportation enterprises. The implementation of the matrix auction in a multi-agent fleet scheduling system is described, and we were able to observe a significant improvement of the task allocation. 1 Introduction In this paper the problem of efficiently allocating transportation tasks in a network of cooperating shipping companies that are independent and self-interested is adressed from an economic point of view. In the highly competitive haulage business, small and medium sized shipping companies that operate locally are often forced to form temporary inter-regional alliances in order to bundle their resources and to establish competitive prices. The business process of a transportation task is often split into subtas..

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

Philosophical logics - a survey and a bibliography

Intensional logics attract the attention of researchers from differing academic backgrounds and various scientific interests. My aim is to sketch the philosophical background of atlethic, epistemic, doxastic and deontic logics, their formal and metaphysical presumptions and their various problems and paradoxes, without attempting formal rigor. A bibliography, concise on philosophical writings, is meant to allow the reader's access to the maze of literature in the field. (orig.)SIGLEAvailable from TIB Hannover: RR 1812(94-17) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman