Lecture Notes in Computer Science Edited by G. Goos, J. Hartmanis and J. van Leeuwen

1000

Advisory Board: W. Brauer D. Gries J. Stoer

Jan van Leeuwen (Ed.)

Computer Science Today

Recent Trends and Developments

Springer

Series Editors

Gerhard Goos, Karlsruhe University, Germany

Juris Hartmanis, Cornell University, NY, USA

Jan van Leeuwen, Utrecht University, The Netherlands

Volume Editor

Jan van Leeuwen Department of Computer Science, Utrecht University Padualaan 14, 3584 CH Utrecht, The Netherlands

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Die D e u t s c h e B i b l i o t h e k - C I P - E i n h e i t s a u f n a h m e

C o m p u t e r sc ience today : r e cen t t rends and d e v e l o p m e n t s / J an van Leeuwen (ed.). - Ber l in ; H e i d e l b e r g ; New Y o r k ; Ba rce lona ; Budapes t ; H o n g Kong ; L o n d o n ; Mi lan ; Paris ; Tokyo : Spr inger , 1995

(Lecture notes in computer science ; 1000) ISBN 3-540-60105-8

NE: Leeuwen, Jan van [Hrsg.]; GT

CR Subject Classification (1991):A.1

ISBN 3-540-60105-8 Springer-Verlag Berlin Heidelberg New York

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Preface

This volume of the series Lecture Notes in Computer Science (and Lecture Notes in Artificial Intelligence) marks a truly unique and festive moment: it is the lO00th volume that is appearing in the series.

To commemorate the special occasion, this volume presents a unique collec- tion of expository papers on major themes that are representative for computer science 'today'. The papers were written by leading experts and teams in the computer science area with a very specific goal in mind, namely to demonstrate the scope and stature of the field today and give an impression of some of the chief motivations and challenges for tomorrow's computer science.

The series was founded in 1973 on the initiative of Klaus Peters and his wife Alice Peters, who were the responsible editors within Springer-Verlag at the time for the mathematics and economics-oriented publishing activities. The successful Lecture Notes in Mathematics (published since 1964) and Lecture Notes in Economics and Mathematical Systems (published since 1968, initially as Lecture Notes in Operations Research and Mathematical Economics and later as Lecture Notes in Operations Research and Mathematical Systems) were the leading examples for the series. It was first named 'Lecture Notes in Computer Science' in an internal Springer memo of Walter Kaufmann-Bfihler to Klaus Peters dated January 23, 1973.

Gerhard Goos, who had become an editor of the Lecture Notes in Economics and Mathematical Systems in 1972, was asked to become editor of the new series and shortly later, on the invitation by Alice Peters in March 1973, Juris Hartmanis joined as series editor as well. With the strategic support of the Advisory Board, Goos and Hartmanis have directed the series since. Under their editorial rule, the series developed into the exceedingly valuable collection of volumes that it is today, indispensable for the practicing scientist in any branch of computer science or related discipline.

It is extremely interesting and educational to look again at the first one- hundred volumes that appeared in the series Lecture Notes in Computer Science and to see how they reflect the gradual formation of computer science as a science through the 1970s in Europe and in the world. There were influential lecture notes from conferences, schools and advanced courses on compiler con- struction, complexity theory, distributed systems, net theory, operating systems, optimization methods, program construction, programming languages and their implementation, and software engineering, to mention just a few of the volumes. Conferences like the International Colloquium on Automata, Languages and Programming (ICALP, starting at Volume 14) and the Symposium on Mathe- matical Foundations of Computer Science (MFCS, starting at Volume 28) were among the first to record their proceedings in the Lecture Notes series.

From the very beginning, course notes such as Sheila Greibach's "Theory of Program Structures: Schemes, Semantics, Verification" (Volume 36), mono- graphs like Robin Milner's "A Calculus of Communicating Systems" (Volume 92), selected Ph.D. theses like Joost Engelfriet's (Volume 20) and Samuel Fuller's

VI Preface

(Volume 31), language documents like "Towards a Formal Description of ADA" (Volume 98) and manuals like Volume 6 on EISPACK (with an extension in Volume 51) were included in the series. The best known 'Lecture Note' from those times undoubtedly is Volume 18: Jensen and Wirth's "PASCAL - User Manual and Report". Volume 100 appeared in 1981, eight years after the se- ries was started. It was the proceedings of the 6th International Workshop on Graph-Theoretic Concepts in Computer Science (WG).

Computer science developed tremendously throughout the 1980s. The ever increasing computational and information-processing capabilities of computers were recognized in all disciplines and led to many 'computational sciences' and the beginnings of present-day information technology. The development of per- sonal computers and workstations on the one hand, and of attractive and power- ful software tools and user-interfaces on the other, made the techniques of com- puter science available to the entire community. It placed enormous demands on the field, requiring both theory and practice to advance with giant leaps.

One consequence of this development was that it triggered an enormous ad- vance in the design of intelligent systems, leading to many new challenges in, e.g., conceptual modeling and formal methods. In 1987 it was decided to devote a special subseries within the Lecture Notes series to Artificial Intelligence, and JSrg Siekmann was asked to be the series editor for this area, starting with Vol- ume 345 in 1988. In the second half of 1993, starting with Volume 764, Jaime G. Carbonell joined to become the second series editor of the Lecture Notes in Artificial Intelligence. To date, over 120 volumes have appeared in the subseries. I joined Goos and Hartmanis as series editor of the Lecture Notes in Computer Science in 1994, starting at Volume 850.

It is instructive to look at the past one-hundred volumes of the Lecture Notes in Computer Science as well, by way of comparison. Volume 900, the pro- ceedings of the 12th Annual Symposium on Theoretical Aspects of Computer Science (STACS'95), appeared in January 1995. Again the Lecture Notes se- ries reflects the massive, new developments in the computer science field. There are volumes devoted to conferences and workshops on algorithms, artificial life, bio-computing, cooperative work, computational geometry, computer-aided ver- ification, constraint programming, cryptography, databases, functional program- ming, high-performance computing and networking, intelligent agents, learning, object-oriented programming, parallel programming, program construction, rea- soning systems, systems engineering and telematics, to mention just a few of the subject areas. Every volume represents a wealth of scientific information, easily accessible and quickly disseminated for study and reference. In turn, the Lecture Notes in Computer Science continue to be a chief instrument in the development of computer science worldwide.

In 1973, the year in which the Lecture Notes in Computer Science started, Donald E. Knuth (American Scientist 61 (1973) p. 708) wrote:

"One of my mathematician friends told me he would be willing to recog- nize computer science as a worthwhile field of study, as soon as it contains 1000 deep theorems. This criterion should obviously be changed to in-

Preface VII

clude algorithms as well as theorems [...]. But even so it is clear that computer science today does not measure up to such a test, if "deep" means that a brilliant person would need many months to discover the theorems or the algorithms. Computer science is still too young for this [in 1973]."

It is clear that computer science passed the criterion years ago but, to quote Donald Knuth (personal correspondence, February 27, 1995) again, it seems that the appearance of the 1000th volume of the Lecture Notes in Computer Science is as good a time as any to celebrate the obvious fact that computer science has come of age. Juris Hartmanis (e-mail correspondence, June 18, 1995) formulated it like this:

"[...] it is a haunting coincidence that LNCS has reached its 1000th volume at this time. To me it has a deeper significance, as if a period of exciting growth has reached a major milestone in the achievements of computer science and the recognition of its impact. This is the time when the Worldwide Web has gained so much visibility and prominence that the Information Superhighway is recognized by politicians as a vital issue and e-mail addresses are given out for the White House. This visibility of computer science is not built on its deepest achievements, but it is proof of the recognition and awareness that computing and communications are changing our societies very fundamentally and, by implication, that computer science is the catalyst for this process."

It is thus only fitting that we have entitled the anniversary volume: Computer Science Today.

Volume 1000 was designed to give a broad view of the achievements and chal- lenges of modern computer science. Stated in this way, it is clear that not even 1000 pages would have been sufficient to give an adequate overview of the field. Besides, many of the Lecture Notes routinely contain the text of invited lectures and surveys that give in-depth accounts of many specialized themes already! As editor of Volume 1000 1 have selected a number of themes which have struck me as being particularly representative for the kind of concerns: in present day com- puter science, from algorithms to software technology to~ multimedia and ethical issues. I am very grateful to all colleagues who have responcFed to the invitation to contribute to the volume and give an exposition of their area of interest and expertise, or just of an exciting new development in the computer science field. Without exception, the support for making this volume a trulF unique one has been overwhelming. I thank each and every author for the contribution to this volume and for the non-trivial amount of time that they have all given to the preparation of their paper for this volume.

The present landmark in the history of the Lecture Notes, in Computer Sci- ence series could only be reached because of the unfailing support of the pub- lisher, Springer-Verlag. Special thanks are due to the in-house Computer Science editors of Springer-Verlag who have been responsible for the series: Alice Peters from the beginning of the series until 1978, Gerhard Rossbach from 1978 until

VIII Preface

1985, and Hans WSssner from 1985 until 1991, with substantial support by Inge- borg Mayer as associate editor from 1976 onward. In 1991 Alfred Hofmann joined Springer-Verlag and assumed the responsibility for the series, with editorial as- sistance in the past two years by Simone Reutner. Angelil~ Bernauer-Budiman has served as production editor for the series since 1981 and supervised the pro- duction of more than 900 volumes. I am very'grateful to my colleague series editors, Gerhard Goos and Juris Hartmanis, and especially to Alfred Hofmann for their help and advice during the preparation of this very special volume in the series Lecture Notes in Computer Science.

While a new 'millennium' in the series is presenting itself and new challenges of the electronic age must be met, we hope that this volume will lead the reader to reminisce about the impact of computer science and to contemplate the many challenges that must be met in the future.

Utrecht, September 1995 Jan van Leeuwen

L e c t u r e N o t e s i n C o m p u t e r S c i e n c e

S e r i e s E d i t o r s

G e r h a r d Goos studied mathematics at the Freie Universit/it Berlin and the Universit/~t Erlangen where he received his Dr.rer.nat. in 1965. After five years at the Technische Universit~t M/inchen, he joined the Universits Karlsruhe as the founding chair of the Informatics Department. From 1983 to 1991 he served as director of the Institute for Sys- tem Technology and then as member of the Board of the GMD, the German National Laboratory for Computer Science. His research interests center on software engineering and compiler technology. He served as chairman of IFIP Working Group 2.4 (on System Programming Languages) from 1981 to 1984, and he is a trustee of the International Com- puter Science Institute (ICSI) at Berkeley since its foundation in 1986. Goos is known in Germany for his textbooks Informatik, eine einfiihrende ~)bersicht (2 volumes, 1971, with F.L. Bauer, now in its 4th edition) and internation- ally for Compiler Construction (1983, with W.M. Waite). He is a series editor of Springer-Verlag's Lectures Notes in Computer Science and an editor of the journals Informatik-Spektrum, Informatik-Forschung und Entwicklung, Formal Aspects of Computing, and Software - Concepts and Tools.

Jur is Ha r tman i s was born in Riga (Latvia) and studied physics at the Philips University in Mar- burg, Germany, where he received his Cand.Phil. degree in 1949. He received his M.A. in mathemat- ics from the University of Kansas in 1951 and his Ph.D. from the California Institute of Technology in 1955. After teaching mathematics at Cornell and Ohio State Universities he joined the GE Research Laboratory in Schenectady, NY in 1958 and was quickly initiated in computer science research. In 1965 he joined Cornell University as the founding chair of the Computer Science Department. Hart- manis has been at Cornell since, except for his sab- baticM leaves at the GMD in Bonn, MSRI in Berke- ley and the Max-Planck-Institut ffir Informatik in Saarbriicken. His research interests center on theory of computation and computational complexity. Hart- manis is a member of the National Academy of Engineering, foreign member of the Latvian Academy of Sciences, Fellow of the American Academy of Arts and Sciences, the New York State Academy of Sciences, and the American Associa-

X Series Editors' Preface

tion for the Advancement of Science, and Charter Fellow of the ACM. In 1993 Hartmanis was awarded with R.E. Stearns the ACM Turing Award, and in 1995 he received a Dr.h.c. from the Universits Dortmund and the Golden Bolzano Medal awarded by the Academy of Sciences of the Czech Republic. He is editor of the Springer-Verlag Lecture Notes in Computer Science, the Journal of Com- puter and System Sciences, the SIAM Journal on Computing, the Journal for Universal Computer Science, and The Chicago Journal of Theoretical Computer Science.

J an van Leeuwen studied mathematics at Utrecht University, where he received his M.Sc. degree in 1969. He continued in a research position in ap- plied mathematics, specializing in the 'informatics' of that time: programming theory, computability, and automata and formal language theory. After obtaining his Ph.D. at Utrecht University in 1972, he went to the US and immersed himself in the many different aspects of computer science. He held positions in computer science at the University of California at Berkeley, the State University of New York at Buffalo (NY), and the Pennsylvania State University. In 1977 he was appointed at Utrecht University again, to head the newly formed Depart- ment of Computer Science. He is a Full Professor of Computer Science at Utrecht University since 1982 and presently serving as Dean of :~he Faculty of Mathe- matics and Computer Science. Jan van Leeuwen has published extensively on the design and analysis of algorithms, from datastructuring and computational geometry to parallel and distributed algorithms. His interests cover a wide spec- trum of research in algorithms and formal methods for computing and other fields that are amenable to theoretical modeling and analysis. He is a member of the International Panel of BRICS (Aarhus, DK) and has served as chair/organizer or program committee member of many conferences and workshops on algo- rithms. He was a consulting editor for the Addison-Wesley Publishing Company (Europe) from 1981 to 1991, managing editor of the 2-volume Handbook of The- oretical Computer Science (now also in a Japanese translation), served on the editorial boards of Information and Computation, the SIAM Journal on Com- puting, and Theoretical Computer Science, and edited or co-edited the following Lecture Notes in Computer Science: Volumes 85, 312, 344, 486, 505/506, 790, 855, and 1000. He became a series editor of the Springer-Verlag Lecture Notes in Computer Science in 1994.

Contents

The New C o m p u t i n g

A Quantum Jump in Computer Science . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 G. Brassard

Artificial Life and Real World Computing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 L. Steels, M. Tokoro

Recurrent Neural Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 H. T. Siegelmann

Scalable Computing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 W.F. McColI

Para l le l a n d D i s t r i b u t e d Sys tems

Efficient Use of Parallel and Distributed Systems: From Theory . . . . . . . . . . . . . . . . . . . . 62 to Practice

B. Monien, R. Diekmann, R. Feldmann, R. Klasing, R. Liiling, K. Menzel, Th. R5mke, U.-P. Schroeder

Experimental Validation of Models of Parallel Computation . . . . . . . . . . . . . . . . . . . . . . . . 78 L. Snyder

Quo Vadetis, Parallel Machine Models? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 J. Wiedermann

Algorithm Design

Templates for Linear Algebra Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115 Z. Bai, D. Day, J. Demmel, J. Dongarra, M. Gu, A. Ruhe, H. van der Vorst

The ART behind IDEAS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141 Th. Beth, A. Klappenecker, T. Minkwitz, A. Niickel

Algorithmic Number Theory and Its Relationship to Computational . . . . . . . . . . . . . . . 159 Complexity

L.M. Adleman

Edge-Coloring Algorithms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172 S. Nakano, X. Zhou, T. Nishizeki

Towards a Computational Theory of Genome Rearrangements . . . . . . . . . . . . . . . . . . . . 184 S. HannenhaUi, P.A. Pevzner

XII Contents

Algebraic Topology and Distributed Computing - A Primer . . . . . . . . . . . . . . . . . . . . . . . 203 M. Herlihy, S. Rajsbaum

O p t i m i z a t i o n and Search

Differential BDDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218 A. AnuchitanukuI, Z. Manna, T.E. Uribe

Algorithmic Techniques for Geometric Optimization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234 P.K. Agarwal, M. Sharir

All the Needles in a Haystack: Can Exhaustive Search . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254 Overcome Combinatorial Chaos?

J. Nievergelt, R. Gasser, F. M~ser, C. Wirth

Fundamental Limitations on Search Algorithms: Evolutionary . . . . . . . . . . . . . . . . . . . . . 275 Computing in Perspective

N.J. Radcliffe, P.D. Surry

Software Technology

Mathematical System Models as a Basis of Software Engineering . . . . . . . . . . . . . . . . . . 292 M. Broy

Formulations and Formalisms in Software Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . 307 M. Shaw, 1). Garlan

The Oz Programming Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324 G. Smolka

Standard Generalized Markup Language: Mathematical and . . . . . . . . . . . . . . . . . . . . . . 344 Philosophical Issues

D. Wood

P r o g r a m m i n g T h e o r y

Avoiding the Undefined by Underspecification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366 D. Gries, F.B. Schneider

Towards a Theory of Recursive Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 374 D. Harel

Chu Spaces and Their Interpretation as Concurrent Objects . . . . . . . . . . . . . . . . . . . . . . . 392 V. Pratt

Abstracting Unification: A Key Step in the Design of . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 406 Logic Program Analyses

M. Bruynooghe, M. Codish, A. Mulkers

Contents XHI

Verification and Reasoning

Programming Satan's Computer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 426 R. Anderson, R. Needham

Petri Net Models of Distributed Algorithms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 441 W. Reisig

Symmetry and Induction in Model Checking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 455 E.M. Clarke, S. ]ha

Alternating Automata and Program Verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 471 M.Y.V~r~i

Reasoning about Actions and Change with Ramification . . . . . . . . . . . . . . . . . . . . . . . . . . 486 E. SandewaU

Intelligent Systems

Trends in Active Vision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 505 J.-O. Eklundh

Computational Machine Learning in Theory and Praxis . . . . . . . . . . . . . . . . . . . . . . . . . . . 518 M. Li, P. Vitd, yi

Fuzzy Sets as a Tool for Modeling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 536 R.R. Yager

Information Retrieval and Informative Reasoning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 549 C.J. ~an Rijsbergen

Database Transaction Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 560 G. Vossen

M u l t i m e d i a and H y p e r m e d i a

Multimedia Authoring Tools: State of the Art and . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 575 Research Challenges

D.C.A. Bulterman, L. Hardrnan

Computational Models for Distributed Multimedia Applications . . . . . . . . . . . . . . . . . . . 592 Th. Kiippner, R. Steinmetz

Hypermedia Systems as Internet Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 608 H. Maurer

Biograph ie s of C o n t r i b u t i n g A u t h o r s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 625

A u t h o r I n d e x . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 643

C o n t r i b u t o r s t o V o l u m e 1000

The following authors, in alphabetical order, have contributed to this anniversary volume of the Lecture Notes in Computer Science.

L.M. Adleman B. Monien P.K. Agarwal A. Mulkers R. Anderson S. Nakano A. Anuchitanukul R. Needham Z. Bai J. Nievergelt Th. Beth T. Nishizeki G. Brassard A. Niicket M. Broy P.A. Pevzner M. Bruynooghe V. Pratt D.C.A. Bulterman N.J. Radcliffe E.M. Clarke S. Rajsbanm M. Codish W. Reisig D. Day Th. RSmke J. Demmel A. Ruhe R. Diekmann E. Sandewall J. Dongarra F.B. Schneider J.-O. Eklundh U.-P. Schroeder R. Feldmann M. Sharir D. Garlan M. Shaw R. Gasser H.T. Siegelmann D. Gries G. Smolka M. Gu L. Snyder S. Hannenhalli L. Steels D. Harel R. Steinmetz L. Hardman P.D. Surry M. Herlihy M. Tokoro S. Jha T.E. Uribe Th. Ks H. van der Vorst A. Klappenecker C.J. van Rijsbergen R. Klasing M.Y. Vardi M. Li P. Vits R. Liiling G. Vossen Z. Manna J. Wiedermann F. Ms C. Wirth H. Maurer D. Wood W.F. McColl R.R. Yager K. Menzel X. Zhou T. Minkwitz