Artificial intelligence from A to Z

Engng Applic. Artif. lntell. Vol. 5, No. 4, pp. 369-371, 1992

0952-1976/92 $5.00 + 0.00 Pergamon Press Ltd

Printed in Great Britain

Book Reviews Designing Autonomous Agents: Theory and Practice from Biology to Engineering and Back, Series on Special Issues of Robotics and Autonomous Systems, edited by PATTIE MAES. The MIT Press, Cambridge, MA (1991). 194 pp., £17.95 (paperback), ISBN 0-262-63135-0. This timely volume focuses on the fundamentals of designing autonomous agents and deals with the theory and practice of such agents from Biology to Engineering and back. Since 1970 the Deliberative Thinking (DT) paradigm has had enormous influence on Artificial Intelligence (AI) research. The idea behind this paradigm is that intelligent tasks may be implemented by a reasoning process operating on a symbolic internal model. Recently, new architectures have emerged, using direct coupling of perception to action, distributedness and decentralization, dynamic interaction with the environment and intrinsic mechanisms to cope with resource limitations and uncertain, vague, fuzzy, and incomplete knowledge. Two key ideas (among several) in these new architectures are that of "emergent functionality" and that of "task-level decomposition," plus the utilization of the perception task in a morespecific format. These new ideas have already achieved some attention in the literature, as well as some promise to revolutionize the field of Autonomous Agents. This volume presents ten (10) contributions as a representative sample of this new line of thinking about autonomous agents in AI. The edited manuscript contains articles by the researcher who originated these ideas; some of the contributions were discussed at the workshop "Representation and Learning in an Autonomous Agent," held in Lagos, Portugal in November 1988. One of the most commendable aspects of the volume is that it presents novel ideas in AI and yet caters well to both novices and experts in the field. The wealth of new ideas, in theory and applications in both the Engineering domain as well as in Biology, makes this manuscript extremely interesting and offers great diversity in the discussions. The editor has clearly identified an area that she considered to be important in AI, and for the most part, I concur with the majority of her decisions. The material in the volume is clear and much of it forms an excellent presentation of the major issues in this area. This is a commendable and important publication. If you want to investigate the theory and applications of Autonomous Agents today, this volume is for you. A. KANDEL

University of South Florida

Artificial Intelligence From A to Z, by JENNY R A G G E T T and WILLIAM BAINS. Chapman & Hall, London (1991). 246pp., £11.95, ISBN 0 412 37950 3. The techniques of artificial intelligence are being used increasingly in applications remote from computer science including law, linguistics, medicine, psychology and a range of commercial disciplines. Professionals in these fields may have little prior knowledge or experience of computing, but may nevertheless feel a requirement to grasp at least some of the essential ideas of AI if they are encountering it in the course of their work. This book is designed to meet the needs of such people by providing a non-technical introduction to a selection of AI concepts. It is not therefore intended for the AI academic, but, to quote the Preface " . . . is written for librarians, lawyers, journalists, consultants, linguists, doctors and a hundred and one other professionals who may encounter AI during the course of their work and want to know what a term means without too much fuss". The format of the book is very simple; topics are listed in alphabetical order, each being given on average one page of explanatory text. Thus, after the short Preface we start straight in with Abduction, Algebra, Algorithm, Alpha-beta pruning, Alvey, and so on; the number of topics is about 170. The book concludes with two appendices. The first, of about seven pages, lists and briefly describes a selection of mainly historical Benchmark AI Programs, while the second, of two pages, lists AI Languages and Environments. An index is provided. There is some cross-referencing between the alphabetical entries, but this seems very haphazard. My major criticism of the book is that despite its being aimed at a lay readership there is no introductory section explaining the overall nature of Artificial Intelligence; in fact there is not even an alphabetical entry under that heading. Is the prospective nontechnical reader supposed to have an intuitive grasp of the nature of AI already? An introduction could also serve to structure the subject area and so to provide a framework into which the various detailed topics could be fitted. Some attempt has been made to do this by allocating the individual entries to the following categories: Expert systems, Funding (of research projects), Games and toy domains, Hardware, General AI terms, General computer terms, Logic, Natural language processing, Neural Nets, Programming techniques, Search, Theory/philosophy and Vision. These topic areas will give some idea of the scope of the book; some of them, such as Expert Systems, are described individually as topics in their own right, while others are not. However, in my view the categorization of topics 369

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BOOK REVIEWS

and the limited cross-referencing system are together inadequate to allow the uninitiated reader to gain more than a very superficial view of a selection of isolated topics. 1 tried the book on my wife, who is professionally trained but whose knowledge of computing is restricted to the use of word processors and non-intelligent information systems. She, like me, felt the lack of a general introduction to set a context. We both also found the quality of the individual entries to vary widely. Some are very good, but others are so terse as to have little value, do not make sufficient concession to the nontechnical reader, or are rather sloppily expressed so that their meaning is not very clear. Another failing of the book, in my eyes, is that no references are provided. A reader might well wish to learn more about some of the topics covered, but no help is given regarding sources of further information. Suitable introductory textbooks should have been suggested, and, for the benefit of the computing professional with no previous knowledge of AI, it might be appropriate within the individual entries to provide more detailed references. Overall I found the book to be rather irritating. I constantly returned to the question of what can reasonably be expected from a volume of this nature. Are non-technical readers really going to seek enlightenment on topics such as Epistemology, Hopfield Nets or Perceptrons in isolation? Or would they much prefer to have some sort of context into which to fit these notions? I incline to the latter view, but I certainly do not believe it is possible to gain the requisite balanced non-technical overview of AI from the material presented. To conclude on a more positive note, the book is moderately priced and may well find a place on the bookshelves of the more mature computing professional with no prior knowledge of AI. As mentioned earlier, some of the topics are quite well explained and illustrated, and such individuals may find it a useful informal lead-in to the subject. I believe that the basic idea behind the book is a reasonable one, and feel that some of the improvements suggested above could lead to a much improved second edition. M. J. P R A T T

Cranfield Institute of Technology Artificial Vision for Mobile Robots: Stereo Vision and Multisensory Perception, by N I C H O L A S A Y A C H E , translated by P E T E R T. S A N D E R . The MIT Press, Cambridge, MA (1991). 345 pp., £40.50, ISBN 0-26201124-7. For some years now, remarkable achievements have been made in computer vision. The most striking among them is the possibility of obtaining information

about the three-dimensional world from video images captured from cameras. This gives mobile robots real autonomy and permits them to act efficiently in a diverse and changing environment. The main technique allowing robots to visually perceive scene information surrounding them is range data acquisition via binocular or trinocular stero vision. For determining the range of a point on a surface or on an edge of object one must find the correspondence of two points perspectively projected from the same point onto the right and left images in the case of binocular stereo vision, or of three points on three images in trinocular stereo case. The mentioned problem of correspondence seems to be one of the most difficult and time-consuming techniques in computer vision. Design of real-time robot vision systems in manufacturing environments urgently requires innovative methodologies for matching of stereo correspondence with high accuracy and efficiency. For this purpose the book "Artificial Vision for Mobile Robots: Stereo Vision and Multisensory Perception", written by Nicholas Ayache and translated from French into English by Peter Sander, is recommended to readers as "a fascinating adventure, which results in autonomous robots capable of perception and reasoning" by Oliver D. Faugeras, a giant of computer vision. Nicholas Ayache is a research director of INRIA. He led a group working on computer vision with the E S P R I T Depth and Motion Analysis Project (or P940 project) which brings together European research centres and industrial partners (INRIA, Matra, ITMI and No6sis in France, the University of Genoa and Elsag in Italy, G E C and the University of Cambridge in Great Britain) to build a vision machine capable of terrain and movement perception in real time. Material included here presents not only the theoretical analysis of the information necessary for the accomplishment of tasks, but also the algorithms really used in the project described, with numerous experimental results. The 17 chapters of the text are divided into two parts: the first part, consisting of 10 chapters, is devoted to passive stereo vision. It involves the computation of a three-dimensional representation of the environment from several images taken simultaneously from different viewpoints. The second part of the book deals with multisensory perception. It presents a uniform formalism for the combination of muitisensory information, providing for the computation of geometric representation and the construction of visual maps. The first two chapters give a general introduction to stereo vision problems. The third chapter defines the concepts of epipolar line and disparity, and describes a method for calibrating a set of cameras, which serves as the foundation for successive computation. The fourth chapter introduces the low-level processing necessary to construct a symbolic representation of the image which is of use for stereo vision. This representation is based on image contours. Two types of contour detec-