Lecture Notes in Computer Science

Lecture Notes in Computer Science Edited by G. Goos, J. Hartmanis and J. van Leeuwen 1012 Advisory Board: W. Brauer D. Gries J. Stoer

Miroslav Bartogek Jan Staudek Ji~i Wiedermann (Eds.) SOFSEM '95: Theory and Practice of Informatics 22nd Seminar on Current Trends in Theory and Practice of Informatics Milovy, Czech Republic November 23 - December 1, 1995 Proceedings ~ Springer

Series Editors Gerhard Goos Universit~it Karlsruhe Vincenz-Priessnitz-Strage 3, D-76128 Karlsruhe, Germany Juris Hartmanis Department of Computer Science, Cornell University 4130 Upson Hall, Ithaca, NY 14853, USA Jan van Leeuwen Department of Computer Science,Utrecht University Padualaan 14, 3584 CH Utrecht,The Netherlands Volume Editors Miroslav Barto~ek, Institute of Computer Science Jan Staudek, Faculty of Informatics Masaryk University, Bure~ova 20 602 00 Brno, Czech Republic Ji~'i Wiedermann Institute of Computer Science, Academy of Sciences of the Czech Republic Pod vodfirenskou v~z[ 2,, 182 07 Prague, Czech Republic Cataloging-in-Publication data applied for Die Deutsche Bibliothek - CIP-Einheitsaufnahme Theory and practice of informatics ; proceedings / SOFSEM '95, 22nd Seminar on Current Trends in Theory and Practice of Informaties, Milovy, Czech Republic, November 23 - December 1, 1995 / Miroslav Bartogek... (ed.). - Berlin ; Heidelberg ; New York ; Barcelona ; Budapest ; Hong Kong ; London ; Milan ; Paris ; Tokyo : Springer, 1995 (Lecture notes in computer science ; Vol. 1012) ISBN 3-540-60609-2 NE: Bartogek, Miroslav [Hrsg.]; SOFSEM <22, 1995, Miloviee>; GT CR Subject Classification (1991): D.1-4, H.1-3,F.1, F.4, H.5 ISBN 3-540-60609-2 Springer-Verlag Berlin Heidelberg New York This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, re-use of illustrations, recitation, broadcasting, reproduction on microfilms or in any other way, and storage in data banks. Duplication of this publication or parts thereof is permitted only under the provisions of the German Copyright Law of September 9, 1965, in its current version, and permission for use must always be obtained from Springer -Verlag. Violations are liable for prosecution under the German Copyright Law. 9 Springer-Verlag Berlin Heidelberg 1995 Printed in Germany Typesetting: Camera-ready by author SPIN 10487212 06/3142-5 4 3 2 1 0 Printed on acid-free paper

Foreword The international Seminar on Current Trends in the Theory and Practice of Informatics SOFSEM'95 was held November 23-December I, 1995, in the conference facilities of the Dev~t skal (i.e., Nine Rocks) Hotel, Milovy, the Czech Republic. It was already the 22nd annual meeting in the series of SOFSEM seminars organized in the Czech Republic or in the Slovak Republic. SOFSEM is a seminar with a long term tradition that has been evolving into its present form for more than 20 years. Founded in 1974, SOFSEM (which stands for SOFtware SEMinar) initially arose through the efforts of Jozef Gruska from the Computing Research Center, Bratislava, and Jill Ho~ej~ from the Central Computing Center of Masaryk University, Brno. Gruska served as the program committee chairman for the first 10 years of SOFSEM's existence. Soon after its establishing, SOFSEM became the foremost Czechoslovak seminar devoted to theoretical and practical problems of software systems. In fact, during those early days of computer science and technology, SOFSEM supplemented the university education and academic research by mediating a fast transfer of the latest relevant knowledge to the SOFSEM audience. Traditionally, this audience consisted 'of university professors, academic researchers, university teaching staff, advanced students, and professionals from the field. First local and later on also international experts have been invited. Each of them was to present a series of lectures related to some recent topics in computer science. The basic format of each SOFSEM consisted of several series of invited talks. Each of them had the duration of 3 to 5 hours. This was complemented by selected contributions of participants presented during two half-days in two parallel sessions. Until 1994, the total duration of SOFSEMs was two weeks. The most substantial changes concerning SOFSEM have been realized since the 'velvet' revolution in Czechoslovakia in 1989. SOFSEM has been transformed from a mainly national seminar into a truly international conference. In 1993, an international advisory board was created to provide assistance to the program committee in the preparation of a scientific program. Beginning with SOF- SEM'95, after two years of exhaustive discussions, SOFSEM was shortened to eight days while almost preserving the number of invited lectures. This was achieved mostly at the expense of shortening the basic lecturing unit from 60 minutes down to 45 minutes and of getting rid of a single free day during the seminar. At the same time SOFSEM proceedings now appear as a volume in the Springer-Verlag series Lecture Notes in Computer Science. Also after the split of Czechoslovakia in 1993 it is still assumed that SOFSEM will continue to be held in either the Czech Republic or the Slovak Republic. Thus, through its numerous invited papers and selected contributed papers as well as its excellent working atmosphere, the current SOFSEM is a mix of a winter school, a conference, and an advanced workshop. Driven by an international advisory board in reflecting the recent trends both in theory and practice, the current SOFSEM prolongs its tradition in striving for multidisciplinarity and

vl generalizations in informatics. At the same time it intends to foster international co-operation among professionals working in various areas of computer science. The present volume of proceedings contains 17 invited papers by renowned researchers and prominent academic professionals. These papers offer a unique opportunity to gain a comprehensive and up-to-date survey over the latest issues in selected areas of informatics such as parallel machine models, fuzzy logics, databases, and software engineering (tools and methods, parallel scientific computing, networked multimedia systems, and geographic information systems). The invited papers are accompanied by 22 contributed papers, selected from 52 submissions. They relate mostly to topics treated in the invited papers, thereby providing a still larger context. Rather than to specialists in any particular area, the proceedings are directed at computer professionals, researchers, and advanced students who hold an interest in the recent state, trends, and hot topics in the field of informatics. We are grateful to the members of the Advisory Board for their proposals for the scientific program of SOFSEM'95. We also wish to thank everyone who submitted a paper for consideration, all Program Committee members for their meritorious work in evaluating the papers, as well as to all subreferees who assisted the Program Committee members in the selection process. We are deeply indebted to all authors of the invited papers and of the accepted contributed papers who prepared their manuscripts according to the specified guidelines with LNCS I~TEX style. Miroslav Barto~ek and Lenka Moty~kovs in their roles of SOFSEM'95 Program Committee Secretaries, deserve special thanks for their enormous help in the preparation of the present proceedings for publication. Many thanks are due to the members of the Organizing Committee who did an excellent job in preparing and conducting SOFSEM'95, as usual. We regret to announce that Tom~ Havl~t -- our colleague, our friend, and the head of the Organizing Committee -- died this summer at the age of 49 following a lengthy disease. Tom served as the chairperson of SOFSEM Organizing Committee for more than I0 years. He contributed significantly to the success of SOFSEM, and we will always acknowledge Tom's efforts. We also thank all institutions that took part in organizing SOFSEM'95 and all sponsors who, through financial support, permitted the invited speakers and advanced students to participate. Last, but not least, we want to thank Jan van Leeuwen, one of the editors of the LHCS series, for his trust in SOFSEM and the people around it. His involvement eventually led, for the first time, to the appearance of these proceedings as a volume in the Springer-Verlag LNCS series. The assistance of Springer-Verlag in the preparation of the volume is highly appreciated as well. Brno, Prague, September 1995 Jan Staudek, Ji~f Wiedermann

O R SOFSEM '95.._ Advisory Board: Dines Bjcrner Peter van Emde Boas Manfred Broy Michal Chytil Georg Gottlob Keith Jeffery Maria Zems163 United Nations University, IIST, Macau University of Amsterdam, the Netherlands Technical University Munich, Germany Arthur D. Little Int., Prague, Czech Republic Technical University Vienna, Austria Rutherford Appleton Laboratory, Oxon, UK NSF, Washington DC, USA Program Committe: Chair: Jan Staudek Jill Wiedermann Secretary: Miroslav Barto~ek Lenka Moty~kovs Members: Jaroslav Krs Jan Pavelka Franti~ek Pls Igor Prlvara Bronislav Rovan Jif/Zlatugka Faculty of Informatics, Masaryk University, Brno Institut of Computer Science, Academy of Sciences of the Czech Republic, Prague Institute of Computer Science, MU Brno Faculty of Informatics, Masaryk University, Brno Faculty of Informatics, Masaryk University, Brno Software Engineering Department, Charles University, Prague Software Engineering Department, Charles University, Prague Institute of Informatics and Statistics, Bratislava Department of Computer Science, Comenius University, Bratislava Faculty of Informatics, Masaryk University, Brno

VIII SOFSEM '95 organized by in cooperation with sponsored by Czech Society for Computer Science Slovak Society for Computer Science Czech ACM Chapter Faculty of Informatics, Masaryk University Brno Institute of Computer Science, MU Brno Department of Computer Science and Engineering, TU Brno Department of Computer Science, Comenius University, Bratislava Institute of Computer Science, Academy of Sciences of the Czech Republic, Prague ApS Brno s.r.o. Arthur D.Little Digital Equipment s.r.o., Czech Republic Help Service s.r.o. Hewlett Packard s.r.o., Czech Republic IBM Czech Republic s.r.o. Oracle Czech s.r.o. Da~Lite Liesegang SOFTEC Bratislava Organizing Committe T. ttavls (chair) J. Staudek (vice-chair) Z. Walletzk~ secretary) Z. Botek P. Hans T. Hrugka J. Kohoutkov~ Z. Mal~fk P. Pfikryl B. Rovan J. Sochor P. Sojka T. Staudek

Contents Invited Papers FUNDAMENTALS Parallel Machine Models: How They Are and Where Are They Going... 1 J. Wiedermann Fuzzy Logic From the Logica! Point of View... 31 P. Hdjek Sense of Direction in Processor Networks... 50 G. Tel Welcoming the Super Turing Theories... 83 H. T. Siegelmann What NARX Networks Can Compute... 95 B. G. Horne, H.T. Siegelmann, C.L. Giles DATABASES Database : Introduction to Problems... 103 K.G. Jeffery Distributed Information Systems... 120 J. Grimson Extending Database Technology... 146 N. W. Paton SOFTWARE ENGINEERING Introducing SSADM4+ and PRINCE... 166 A. J. G. Betts Formal Methods in Practice: A Comparison of two Support Systems for Proof... 184 J. C. Bicarregui, B.M. Matthews Development of Safety-Critical Real-Time Systems... 206 H. Rischel, J. CueUar, S. Mark, A.P. Ravn, L Wildgruber Why Use Evolving Algebras for Hardware and Software Engineering?... 236 E. BSrger

PARALLEL ~ DISTRIBUTED SYSTEMS, SCIENTIFIC COMPUTING Experience with Chorus... C. Bae, G. Bernard, D. Conan, Q.H. Nguyen, C. Taconet High-Level Languages for Parallel Scientific Computing... B. Chapman, P. Mehrotra, H.P. Zima 272 292 MULTIMEDIA, HYPERTEX On Some New Aspects of Networked Multimedia Systems... 315 H. Maurer Quo Vadis GIS: From GIS to GIMS and Open GIS... 334 A. Limpouch, K. Charvdt WWW - The World Wide Web... 350 V.A. Marshall Contributed Papers Implementation of Higher-Order Unification Based on Calculus of Explicit Substitution... P. Borovansk~ A Modular History-Oriented Access Structure for Bitemporal Relational Databases... A. Cappelli, C. De Castro, M.R. Scatas Software Engineering Meets Human-Computer Interaction: Integrating User Interface Design in an Object-Oriented Methodology... H.-W. Gellersen Parsing of Free-Word-Order Languages... T. Holan, V. Kubo~, M. Pldtek Distributed Algorithm for Finding a Core of a Tree Network... E. Jennings Stepwise Synthesis of Reactive Programs... P. Kozdk A Simple and Efficient Incremental LL(1) Parsing... W.X. Li 363 369 375 379 385 391 399

xi Fundamentals of Contex-Sensitive Rewriting... S. Lucas Constraint Logic Programming with Fuzzy Sets... L. Matyska, H. Bureg Parallel Processing of Image Database Queries... F. Meunier, P. Zemdnek Maximum Flow Problem in Distributed Environment... L. MotySkovd Fuzzy Set Theory and Medical Expert Systems: Survey and Model... N.H. Phuong The Fusion Object-Oriented Method: an Evaluation... A. Pirotte, T. van den Berghe, E. Zimanyi Integration of Object-Oriented Analysis and Algebraic Specifications... Z. Repaskd On the Implementation of Some Residual Minimizing Krylov Space Methods... M. Rozlo2n~7~, Z. Strakog A Formal Lazy Replication Regime for Spreading Conversion Functions Over Objectbases... C. Smith, C.A. Tau Hopfleld Languages... J. :~(ma Inconsitency Conflict Resolution... J. ~tuller A Methodology for Performance and Scalability Analysis... E. Tambouris, P. van Santen On the Efficiency of Superscalar and Vector Computer for Some Problems in Scientific Computing... M. T~ma, M. Rozlo2nz7~ Logic Programming in RPL and RQL... P. Vojtdg, L. PauhT~ Recognition of Handwritten Characters Using Instance-Based Learning Algorithms... J. 2i2ka, L ~najddrkovd 405 413 419 425 431 437 443 449 455 461 469 475 481 487 493 Author Index 499