- Email: [email protected]
Dimensions and tolerances in shape design
with the movelist End' There are occasional statements which would have been appropriate in the original lecture notes but which are not appropriate in the new context, e.g. 'In the programming lectures we will see how to w r i t e . . . '. There are also some phrases such as 'That looks OK', which might have been better worded. There are now several texts surveying the field and philosophical issues of Artificial Intelligence, but few of these give the detailed instruction and knowledge so vital to an apprecia-
tion of the difficulties inherent in programming a computer- to operate on semantic information. In providing the detailed instruction this book makes an excellent companion to the general texts and a firm foundation for later more advanced work. Apart from its intended use as a reader for students the book should be of particular interest to those who want to check whether the techniques might someday be applied in their own line of work -- some of the tochniques have potentially a wide range of application - and to those who are keen to know something about the
design o! intelligent slaw' machine,. ]-he b~ok might also attract readel who enjoy intellectual puzzles ,is pastime for the pages are 2ic:h ill knotty problems. For the teacher there are useful appendices on teaching methods, the course structure, examination questions, further reading, and a selection of comments made by past students. Unfortunately there is no index. The book is good value for money at £7.50.
Roger Gi// University of Bristol
Artificial intelligence and pattern recognition in computer aided design Edited by Jean-Claude Latombe, North Holland (1978) 510 pp, $60 This book contains the twenty papers of the IFIP Working Conference held at Grenoble, France, in March 1978. The majority of papers focus upon a particular application area while attempting to describe some technical or theoretical concept. There are five papers covering graphics, four on aspects of circuit design, five describing the use of A.I. techniques in CAD, three on design knowledge representation and two excellent papers, one by Akin, the other by Herion which involve no computing and are not expositions of either A.I. or P.R. Presumably in the interests of rapid production the book has been compiled directly from the author's typescripts. Unfortunately this has led to many unnecessary errors of translation nd printing.
The book is aimed at those who are developing CAD systems. Latombe, in his preface, described the conference as a 'compendium of papers about the current and potential impact and use of A.I. and P.R. theories and techniques on CAD'. As such, the book might be expected to focus upon A.I. and P.R., but this intention is not realised. All but six of the papers are centred upon CAD. The A.I. papers stem from the engineering rather than the linguistic or psychological traditions within A.I., and are biased away from theoretical insight towards practical systems. In a conference intended to draw together strands from previously disparate fields, it might be expected that papers would display high standards of scholarship when dealing with referencing and bibliographies, so as to assist new entrants to this research. This expectation is not borne out. For instance the papers considering
the representation of design knowledge fail to mention Minsky's seminar paper of 1975 l, which describes a theory designed to cope with movement in add reasoning about three dimensional space. Such omissions damage the book's authority and make it difficult to recommend it as an introduction for workers in CAD to the disciplines of A.I. and P.R. Nevertheless this book is valuable in that it highlights the importance of A.I. as a means for the development of C.A.D. 1 Minsky, M 'A framework for representing knowledge' in Winston, P H The Psychology of Computer Vision. McGrawHill, New York (1975)
D S W/Hey University of Liverpool
Dimensions and tolerances in shape design Robin Hi//yard, University of Cambridge (1978)pp 186 Often when researchers approach the design of computer procedures which will perform tasks, formerly done by men, they discover that certain aspects, considered until then as straight-
244
forward, need careful study and formal treatment before any programming may be done. The analysis of dimensions and tolerances is a typical example of this kind, as it turned to be an essential step towards developing methods for generating engineering drawings of three-dimensional
objects. In this respect the book is an important step in the development of CAD/CAM systems. The book is concerned mainly with computeraided mechanical design, but developers of similar systems in other design areas (structural engineering, architecture, etc.) would perhaps benefit
computer-aided desigl
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
! from studying the ideas presented in it. In order to put the structure developed in this work into a practical CAD/CAM system attractable to designers much work still has to be done. Thus designers may wish to wait for further developments in this area, and for the appearance of a text describing a more comprehensive system. The basic ideas of the analysis of dimensions and tolerances can be read in a paper co-authored by Hillyard (CAD Vo110 No 3). There he develops the concept of stiffeners as a way to represent the dimensioning of an object, analyzes the various types of stiffeners, introduces their basic algebraic representation, and points out the problem of inferring the existence of stiffeners which are normally not shown explicitly on drawings. The book offers a more systematic and rigorous discussion of these topics, but adds conceptually very little in comparison to the paper. One important new contribution is the discussion of additional methods for assessing alternative stiffening schemes. The most important part is, however (as the author himself suggests), the algorithms presented for automatic stiffening in two and three dimensions. Yet, this part leaves certain questions without satisfactory answers. The author seems to suggest that at least at the current state of development, the assessment methods are in general impractical to be used, especially for three dimensional objects. Then in describing the algorithms very little reasoning is given to the priority setting among the different types of stiffeners, except perhaps attempting to respond to the normal designers intentions as the author sees them. We may expect improvement of the automatic determination of a dimensioning scheme, as a result of further research, stimulated by this book.
volume 11 number 4 july 1979
, Some readers may find the readability of the book somewhat difficult. In a first reading it is of less importance to follow all the details of the mathematical representation of each stiffener. Some problems with the layout of the book (for which the author apologizes) may also make the task a little more difficult. On the other hand the book contains many nice and helpful illustrations. The appendix offers a brief introduction to some concepts important for the understanding of the book. Thus it helps to bring the potential reader to a common ground in respect to the
mathematics, procedural language (for describing algorithms), definitions, etc., used by the author. In short, the book is certainly worth the attention of anyone interested in the development of CAD systems. The last chapter describes aspects and ideas which need further research. These and others should be interlinked with the basic concepts suggested in this book in order to create an essential component of CAD/CAM systems.
Yacov Yasky Carnegie-Mellon University
Literature available Offshore structures A monograph on the analysis of offshore structures with ASAS/FATJACK-related computer programs has been published by Atkins Research and Development, of Epsom, UK. The information contained should prove of value to engineers concerned with the structural design, fatigue life, launching and installation of steel jackets - and could also be of interest to engineers working in other areas. A 16-page illustrated document outlines the analytical capabilities of the ASAS-G finite element system, and describes work performed in static and dynamic analyses, dynamic design wave analysis, dynamic fatigue analysis, spectral fatigue analysis (using the FAT] ACK program), seismic analysis, the simulation of jacket launching, and floating stability during installation. (Further information from Atkins Research and Development, Woodcote Grove, Ashley Road, Epsom, Surrey, England; tel: Epsom (03727) 26140.)
CAM terms CAM have published a 2nd edition of
their Glossary of CAM Terms. The glossary contains: • approximately 1350 terms, bound into a notebook • a preface describing arrangement and organization • a cross-reference for assistance in locating preferred terminology • lists of acronyms for terms and organizations
The glossary does not contain: • terms with commonplace meanings, or those found in everyday vocabulary • special meanings that have been arbitrarily assigned • definitions of terms normally found in programmer or user manuals.
The glossary is available from CAM's Library for the cost of materials and reproduction: $13.00. (CAM-I Library Coordinator, 611 Ryan Plaza Drive, Suite 1107, Arlington, Texas 76011, USA Tel: (817) 265-5328)
245
tion of the difficulties inherent in programming a computer- to operate on semantic information. In providing the detailed instruction this book makes an excellent companion to the general texts and a firm foundation for later more advanced work. Apart from its intended use as a reader for students the book should be of particular interest to those who want to check whether the techniques might someday be applied in their own line of work -- some of the tochniques have potentially a wide range of application - and to those who are keen to know something about the
design o! intelligent slaw' machine,. ]-he b~ok might also attract readel who enjoy intellectual puzzles ,is pastime for the pages are 2ic:h ill knotty problems. For the teacher there are useful appendices on teaching methods, the course structure, examination questions, further reading, and a selection of comments made by past students. Unfortunately there is no index. The book is good value for money at £7.50.
Roger Gi// University of Bristol
Artificial intelligence and pattern recognition in computer aided design Edited by Jean-Claude Latombe, North Holland (1978) 510 pp, $60 This book contains the twenty papers of the IFIP Working Conference held at Grenoble, France, in March 1978. The majority of papers focus upon a particular application area while attempting to describe some technical or theoretical concept. There are five papers covering graphics, four on aspects of circuit design, five describing the use of A.I. techniques in CAD, three on design knowledge representation and two excellent papers, one by Akin, the other by Herion which involve no computing and are not expositions of either A.I. or P.R. Presumably in the interests of rapid production the book has been compiled directly from the author's typescripts. Unfortunately this has led to many unnecessary errors of translation nd printing.
The book is aimed at those who are developing CAD systems. Latombe, in his preface, described the conference as a 'compendium of papers about the current and potential impact and use of A.I. and P.R. theories and techniques on CAD'. As such, the book might be expected to focus upon A.I. and P.R., but this intention is not realised. All but six of the papers are centred upon CAD. The A.I. papers stem from the engineering rather than the linguistic or psychological traditions within A.I., and are biased away from theoretical insight towards practical systems. In a conference intended to draw together strands from previously disparate fields, it might be expected that papers would display high standards of scholarship when dealing with referencing and bibliographies, so as to assist new entrants to this research. This expectation is not borne out. For instance the papers considering
the representation of design knowledge fail to mention Minsky's seminar paper of 1975 l, which describes a theory designed to cope with movement in add reasoning about three dimensional space. Such omissions damage the book's authority and make it difficult to recommend it as an introduction for workers in CAD to the disciplines of A.I. and P.R. Nevertheless this book is valuable in that it highlights the importance of A.I. as a means for the development of C.A.D. 1 Minsky, M 'A framework for representing knowledge' in Winston, P H The Psychology of Computer Vision. McGrawHill, New York (1975)
D S W/Hey University of Liverpool
Dimensions and tolerances in shape design Robin Hi//yard, University of Cambridge (1978)pp 186 Often when researchers approach the design of computer procedures which will perform tasks, formerly done by men, they discover that certain aspects, considered until then as straight-
244
forward, need careful study and formal treatment before any programming may be done. The analysis of dimensions and tolerances is a typical example of this kind, as it turned to be an essential step towards developing methods for generating engineering drawings of three-dimensional
objects. In this respect the book is an important step in the development of CAD/CAM systems. The book is concerned mainly with computeraided mechanical design, but developers of similar systems in other design areas (structural engineering, architecture, etc.) would perhaps benefit
computer-aided desigl
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
! from studying the ideas presented in it. In order to put the structure developed in this work into a practical CAD/CAM system attractable to designers much work still has to be done. Thus designers may wish to wait for further developments in this area, and for the appearance of a text describing a more comprehensive system. The basic ideas of the analysis of dimensions and tolerances can be read in a paper co-authored by Hillyard (CAD Vo110 No 3). There he develops the concept of stiffeners as a way to represent the dimensioning of an object, analyzes the various types of stiffeners, introduces their basic algebraic representation, and points out the problem of inferring the existence of stiffeners which are normally not shown explicitly on drawings. The book offers a more systematic and rigorous discussion of these topics, but adds conceptually very little in comparison to the paper. One important new contribution is the discussion of additional methods for assessing alternative stiffening schemes. The most important part is, however (as the author himself suggests), the algorithms presented for automatic stiffening in two and three dimensions. Yet, this part leaves certain questions without satisfactory answers. The author seems to suggest that at least at the current state of development, the assessment methods are in general impractical to be used, especially for three dimensional objects. Then in describing the algorithms very little reasoning is given to the priority setting among the different types of stiffeners, except perhaps attempting to respond to the normal designers intentions as the author sees them. We may expect improvement of the automatic determination of a dimensioning scheme, as a result of further research, stimulated by this book.
volume 11 number 4 july 1979
, Some readers may find the readability of the book somewhat difficult. In a first reading it is of less importance to follow all the details of the mathematical representation of each stiffener. Some problems with the layout of the book (for which the author apologizes) may also make the task a little more difficult. On the other hand the book contains many nice and helpful illustrations. The appendix offers a brief introduction to some concepts important for the understanding of the book. Thus it helps to bring the potential reader to a common ground in respect to the
mathematics, procedural language (for describing algorithms), definitions, etc., used by the author. In short, the book is certainly worth the attention of anyone interested in the development of CAD systems. The last chapter describes aspects and ideas which need further research. These and others should be interlinked with the basic concepts suggested in this book in order to create an essential component of CAD/CAM systems.
Yacov Yasky Carnegie-Mellon University
Literature available Offshore structures A monograph on the analysis of offshore structures with ASAS/FATJACK-related computer programs has been published by Atkins Research and Development, of Epsom, UK. The information contained should prove of value to engineers concerned with the structural design, fatigue life, launching and installation of steel jackets - and could also be of interest to engineers working in other areas. A 16-page illustrated document outlines the analytical capabilities of the ASAS-G finite element system, and describes work performed in static and dynamic analyses, dynamic design wave analysis, dynamic fatigue analysis, spectral fatigue analysis (using the FAT] ACK program), seismic analysis, the simulation of jacket launching, and floating stability during installation. (Further information from Atkins Research and Development, Woodcote Grove, Ashley Road, Epsom, Surrey, England; tel: Epsom (03727) 26140.)
CAM terms CAM have published a 2nd edition of
their Glossary of CAM Terms. The glossary contains: • approximately 1350 terms, bound into a notebook • a preface describing arrangement and organization • a cross-reference for assistance in locating preferred terminology • lists of acronyms for terms and organizations
The glossary does not contain: • terms with commonplace meanings, or those found in everyday vocabulary • special meanings that have been arbitrarily assigned • definitions of terms normally found in programmer or user manuals.
The glossary is available from CAM's Library for the cost of materials and reproduction: $13.00. (CAM-I Library Coordinator, 611 Ryan Plaza Drive, Suite 1107, Arlington, Texas 76011, USA Tel: (817) 265-5328)
245