International Journal on Artificial Intelligence Tools

This paper deals with the problems stemming from the parsing of long sentences in quasi free word order languages. Due to the word order freedom of a large category of languages including Greek and the limitations of rule-based grammar parsers in parsing unrestricted texts of such languages, we propose a flexible and effective method for parsing long sentences of such languages that combines heuristic information and pattern-matching techniques in early processing levels. This method is deeply characterized by its simplicity and robustness. Although it has been developed and tested for the Greek language, its theoretical background, implementation algorithm and results are language independent and can be of considerable value for many practical natural language processing (NLP) applications involving parsing of unrestricted texts.

This paper describes a generic, knowledge-based mechanism for selecting among a fixed set of alternatives. The mechanism, termed sponsor-selector has been used as a control mechanism in a number of different knowledge-based systems including problem-solver integration applications in routine design, diagnostic problem-solving, and navigational planning. For design, the DSPL language uses sponsor-selectors to select between alternate, fixed plans to determine the best approach for the design of an artifact. For diagnosis, the Peirce and TIPS system used sponsor-selectors as the overall control mechanism, determining which problem-solver, out of a group of problem-solving agents, to select under particular problem solving conditions. For navigation planning, the Router system used the sponsor-selector mechanism and the TIPS architecture to select between alternate problem-solving strategies. problem-solving approaches. We describe in this paper the general architecture of the sponsor-selector mechanism and how this mechanism was used in the 4 described systems, along with some performance measures and results.

A computational model for the acquisition of knowledge from encyclopedic texts is described. The model has been implemented in a program, called SNOWY, that reads unedited texts from The World Book Encyclopedia, and acquires new concepts and conceptual relations about topics dealing with the dietary habits of animals, their classifications and habitats. The program is also able to answer an ample set of questions about the knowledge that it has acquired. This paper describes the essential components of this model, namely semantic interpretation, inferences and representation, and ends with an evaluation of the performance of the program, a sample of the questions that it is able to answer, and its relation to other programs of similar nature.

In this paper we present two algorithms for building lexicons in Directed Acyclic Word-Graphs (DAWGs). The two algorithms, one for deterministic and the other for non-deterministic DAWGs, can be used instead of the traditional subset construction method. Although the proposed algorithms do not produce the optimal DAWG (i.e., the one with the minimum number of states), they are simple, fast and able to build the DAWG incrementally, as new words are added to the lexicon. Thus, building large lexicons in a DAWG structure becomes an easy task, even for a modest computer.

The development of more powerful Concurrent Constraint Logic Programming (CCLP) languages depends largely on the development of environments that facilitate the specification and integration of constraints in the semantics of a logic program and automatically extract the inherent parallelism of Logic Programming. This paper presents a novel method for automating the parallel AND/OR execution of CCLP applications. This method consists of two stages. The first stage translates a logic program into an equivalent Attribute Grammar providing a common language in which the specifications of constraints and the semantics of a logic program can be expressed. The second stage evaluates this Attribute Grammar using MPAGE, a Multipass Parallel Attribute Grammar Evaluation algorithm. Support for the processing of constraints in the logic program is provided with the creation of a dependency graph between the variables of a logic rule during the first stage. Using this dependency graph MPAGE delays, if necessary, the evaluation of variables in a constraint until they become bound at some later point in processing. As a result our method supports rule representations in CLP languages with no restrictions on the ordering of subgoals. Furthermore, during execution MPAGE allows single rules in a CLP program to deal with multiple assignments of bindings, thus generating a minimal number of processes. Finally, this method is independent from the underlying hardware and its memory organization, therefore it can be implemented on both shared and distributed memory systems.

The purpose of this paper is to provide a survey of state of the art fuzzy logic applications in the field of transportation, illustrating the usefulness, and the promising future of the fuzzy approach. The majority of the discussion covers the area of fuzzy control. A wide range of Fuzzy Logic Controllers (FLCs) is discussed, ranging from traffic, to aircraft controllers. Although the majority of applications are to surface transportation, surveys of several aerospace applications are also given.