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

An adaptive deductive planning system

A generic planning system is introduced which allows for custom building of planners able to generate plans for different plan consumers in the context of intelligent support systems. All planners are adapted to the pecularities of different plan consumers, to their domain knowledge, their typical behavior, their preferences, and their utilization of plans. The necessary knowledge sources of the generic planner are fixed in order to enable it to procedure plans of a certain specificity. Its control strategy is described in a formal specification language containing constructs which allow for the configuration of characteristic parts of the control strategy. The customized planners are defined by executable specifications. An application of the approach to deductive planning based on a modal-temporal logic is shown. It is shown in an example how needs of different plan consumers in an intelligent help system can be met by a deductive planner. (orig.)SIGLEAvailable from TIB Hannover: RR 1812(94-06) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

Complement extraction lexical rules and argument attraction

In (Mueller, 1994), several problems with the processing of complement extraction lexical rules (CELRs) Pollard and Sag, 1994, Ch. 9) are discussed. CELRs destroy the ordering information implicity contained in the COMPS list, making it impossible to assign structural case without default mechanisms (which would be an extension of the basic HPSG formalism). Furthermore, it can be shown that the ARG-S list - a static list suggested by Pollard and Sag to take over the function of the COMPS list in Binding Theory - cannot be used for case assignment. This paper aims to demonstrate how these problems can be solved by use of a dynamically constructed ARG-S list. Together with a modified schema for the construction of German verb clusters, this dynamic list allows for an application of CELRs to both auxiliaries and main verbs, which explains the frontability of subjects and von-PPs in passive constructions, as well as the frontability of subjects in perfect constructions. The proposed account also solves some implementational problems caused by a variable COMPS list. (orig.)Available from TIB Hannover: RR 1812(97-08) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

The definition of Kernel Oz

Oz is a concurrent language providing for functional, object-oriented, and constraint programming. This paper defines Kernel Oz, a semantically complete sublanguage of Oz. It was an important design requirement that Oz be defineable by reduction to a lean kernel langauge. The definition of Kernel Oz introduces three essential abstractions: the Oz universe, the Oz calculus, and the actor model. The Oz universe is a first-order structure defining the values and constraints Oz computers with. The Oz calculus models computation in Oz as rewriting of a class of expressions modulo a structural congruence. The actor model is the informal computation model underlying Oz. It introduces notions like computation spaces, actors, blackboards, and threads. (orig.)SIGLEAvailable from TIB Hannover: RR 1812(94-23) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany); Commission of the European Communities (CEC), Brussels (Belgium)DEGerman

Planning from second principles - a logic-based approach

In this paper, a logical formalization of planning from second principles is proposed, which relies on a systematic decomposition of the planning process. Deductive inference processes with clearly defined semantics formalize planning from second principles. Plan modification is based on a deductive approach which yields provably correct modified plans. Reusable plans are retrieved from a dynamically created plan library using a description logic as a query language to the library. Apart form sequential plans, this approach enables a planners to effiently reuse and modify plans containing control structures like conditionals and iterations. (orig.)Available from TIB Hannover: RR 1812(94-13) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

Scalability of multi-agent systems Proposal for a dissertation

This work proposes a generic approach for achieving scalability of multiagent-systems (MAS). The key to reach that goal is to introduce a self-organization mechanism allowing systems to configure themselves to any application scale and nature. Here, I shall outline such a mechanism, which can be introduced to any multi-agent system. I focus on two systems, InteRRaP and MECCA, and on two applications, the transportation domain, realized using InteRRaP agents, and a traffic telematics application modelled with MECCA agents. All systems and applications are briefly characterized in this work and relations to other fields of research are pointed out. (orig.)SIGLEAvailable from TIB Hannover: RR 2041(97-02) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSiemens AG Energieerzeugung KWU, Erlangen (Germany)DEGerman

A calculus for higher-order concurrent constraint programming with deep guards

We present a calculus providing an abstract operational semantics for higher-order concurrent constraint programming. The calculus is parameterized with a first-order constraint system and provides first-class abstraction, guarded disjunction, committed-choice, deep guards, dynamic creation of unique names, and constraint communication. The calculus comes with a declarative sublanguage for which computation amounts to equivalence transformation of formulas. The declarative sublanguage can express negation. Abstractions are referred to by names, which are first-class values. This way we obtain a smooth and straightforward combination of first-order constraints with higher-order programming. Constraint communication is asynchronous and exploits the presence of logic variables. It provides a notion of state that is fully compatible with constraints and concurrency. The calculus serves as the semantic basis of Oz, a programming language and system under development at DFKI. (orig.)SIGLEAvailable from TIB Hannover: RR 1812(94-03) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany); Commission of the European Communities (CEC), Brussels (Belgium)DEGerman

Classification and representation of types in TDL

TDL is a typed feature-based representation language and inference system, specifically designed to support highly lexicalized constraint-based grammar theories. Type definitions in TDL consist of type and feature constraints over the full Boolean connectives together with coreferences, thus making TDL Turing-complete. TDL provides open- and closed-world reasoning over types. Working with partially as well as with fully expanded types is possible. Efficient reasoning in TDL is accomplished through specialized modules. In this paper, we will highlight the type/inheritance hierarchy module of TDL and show how we represent conjunctively and disjunctively defined types. Negated types and incompatible types are handled by specialized bottom symbols. Redefining a type only leads to the redefinition of the dependent types, and not to the redefinition of the whole grammar/lexicon. Undefined types are nothing special. Reasoning over the type hierarchy is partially realized by a bit vector encoding of types, similar to the one used in Ait-Kaci's LOGIN. However, the underlying semantics does not harmonize with the open-world assumption of TDL. Thus, we have to generalize the GLB/LUB operation to account for this fact. The system, as presented in the paper, has been fully implemented in COMMON LISP and is an integrated part of a large NL system. It has been installed and successfully employed at other sites and runs on various platforms. (orig.)SIGLEAvailable from TIB Hannover: RR 1812(95-17) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Regular path expressions in feature logic

We examine the existential fragment of a feature logic, which is extended by regular path expressions. A regular path expression is a subterm relation, where the allowed paths for the subterms are restricted to any given regular language. We will prove that satisfiability is decidable. This is achieved by setting up a quasi-terminating rule system. (orig.)SIGLEAvailable from TIB Hannover: RR 2041(93-17) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

Typed feature structures, definite equivalences, greatest model semantics, and nonmonotonicity

Typed feature logics have been employed as description languages in modern type-oriented grammar theories like HPSG and have laid the theoretical foundations for many implemented systems. However, recursivity pose severe problems and have been addressed through specialized powerdomain constructions which depend on the particular view of the logician. In this paper, we argue that definite equivalences as introduced by Smolka can serve as the formal basis for arbitrarily formalized typed feature structures and typed feature-based grammars/lexicons, as employed in, e.g., TFS or TDL. The idea here is that type definitions in such systems can be transformed into an equivalent definite program, whereas the meaning of the definite program then is identified with the denotation of the type system. Now, models of a definite program P can be characterized by the set of ground atoms which are logical consequences of the definite program. These models are ordered by subset inclusion and, for reasons that will become clear, we propose the greatest model as the intended interpretation of P, or equivalent, as the denotation of the associated type system. Our transformational approach has also a great impact on nonmonotonically defined types, since under this interpretation, we can view the type hierarchy as a pure transport medium, allowing us to get rid of the transitivity of type information (inheritance), and yielding a perfectly monotonic definite program. (orig.)SIGLEAvailable from TIB Hannover: RR 1812(95-20) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman