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CADCAM integration
CADCAM integration
become an integrated CADCAM system in the future.
Integration of CA D/CA M, D Kochan (Ed), North-Holland, Amsterdam (1984) 283 approx A5 pp Dfl 110
Graphics dictionary
This book is the Proceedings of the IFIP WG5 2/WG5 3 Working Conference on the Integration of CADCAM, held near Dresden in early November 1983. This time the proceedings are genuine and contain a record of the discussion after each session. Since a number of the working group members have been working in this field for two decades or more the discussion is backed by experience. Despite the A5 pages there are some 100 000 words in the text. Its only blemish is the quality of the English which would have been easier to read in places if it had been subject to more editing. The papers reflect the authors' efforts to get integrated systems into use in industry. They indicate that it will be some time yet before all aspects of design and manufacture are integrated into one system with all the business information. At present there is the choice between more efficient syst.ems for particular products and the less efficient systems which are general purpose. There is also the situation that graphics may only represent a quarter of the information which has to be stored and manipulated for a product and the problem is the form in which all the disparate information should be stored in a data base. In a large organisation the choice between a central data base and a distributed one weighs heavily. There is also the problem which has arisen due to the evolution of CAD and CAM. There can be several packages obtained by different departments and thus the need to transfer information between these. As NC users found, standard interfaces like CLDATA are essential to avoid the factorial growth in interfacing programs which would otherwise be needed. All these topics are aired in an unbiased way and these proceedings can be recommended to anyone who has to specify or develop any elements of a system which may need to
Dictionary of computer graphics J Vince, Francis Pinter (Publishers), London (1984) 132 approx A5 pp £15
W H P Leslie
Advanced relational theory The theory of relational databases, David Maler, Computer Science Press (1983) 637pp 428.95
On the dust cover the publisher claims this book to be 'an invaluable aid to student, teacher and professional alike'. However, the author, in the introduction, says that the primary reason for writing it was to describe in layman's terms some of the words and concepts often employed in technical literature. I think that it has turned out that the meagre material in the book would have been more convenient to use if it had been organized in a series of themes with an index to link the terms to the text. As it is, a topic such as colour is dealt with under 12 different entries ranging from 'additive colour' to 'value.' It is really advisable to read all the entries because although there is a lot of duplication of the information under these entries there is no complete description of the way colour is dealt with in computer graphics nor is there an index to lead you to all the entries. A similar problem arises with the references. These are listed under 'colour', 'hidden line removal', 'shading and illumination', modelling' and 'miscellaneous' and are very up to date with the most recent being March 1984. Within each section they are in alphabetical order of author and are not numbered. Where they are referred to in the text there are occasions where all the titles have to be scanned because the name in the text turns out not to be the author's but in the title. For example, the 8 entries in the text about smoothed curves or surfaces mention Bezier and quadric but omit Coon's patches. Coon appears in the references under Forrest in the title of an article. In my'opinion the book is not good value and it would be better to consult a good book on computer graphics with an adequate index.
The purpose of the book, as stated by the author, is to 'give a student sufficient background to read recent papers in relational theory'. In that regard, the book is very successful: it is a most impressive compendium of current topics, along with basic theory in the field of relational databases. It covers the ground customarily explored by most other books dealing with this subject, and it includes additional topics such as the theory of data representation and database semantics, which those books typically mention only briefly, if at all. The material is presented in a well organized, coherent, and notationally standardized manner. Each chapter includes, in addition to theory (which is presented mostly through lemmas and theorems), a clear introductory paragraph, definitions, many examples, and a pertinent bibliography that may facilitate further study of the subject discussed in that chapter. The extensive list of exercises at the end of each chapter will be welcomed by educators who choose the book as a text for an advanced relational database course. In the preface, the author describes the source of the book as notes he wrote for a graduate seminar in relational database theory. Indeed, the graduate student and the professional database research scientist will find the book a comprehensive reference to relational database theory. I suspect, however, that it is much too advanced to be used as a text for an undergraduate course, or for that matter for any readership not already familiar with database theory in general, with set theory, and in particular with relational calculus. The abundant use of examples does not always facilitate the comprehension of the material: it seems like they are used in many cases to introduce new concepts, as much as for illustrating those already discussed.
W H P Leslie
Y Kalay
volume 1 7 number 1 january/february 1985
47
become an integrated CADCAM system in the future.
Integration of CA D/CA M, D Kochan (Ed), North-Holland, Amsterdam (1984) 283 approx A5 pp Dfl 110
Graphics dictionary
This book is the Proceedings of the IFIP WG5 2/WG5 3 Working Conference on the Integration of CADCAM, held near Dresden in early November 1983. This time the proceedings are genuine and contain a record of the discussion after each session. Since a number of the working group members have been working in this field for two decades or more the discussion is backed by experience. Despite the A5 pages there are some 100 000 words in the text. Its only blemish is the quality of the English which would have been easier to read in places if it had been subject to more editing. The papers reflect the authors' efforts to get integrated systems into use in industry. They indicate that it will be some time yet before all aspects of design and manufacture are integrated into one system with all the business information. At present there is the choice between more efficient syst.ems for particular products and the less efficient systems which are general purpose. There is also the situation that graphics may only represent a quarter of the information which has to be stored and manipulated for a product and the problem is the form in which all the disparate information should be stored in a data base. In a large organisation the choice between a central data base and a distributed one weighs heavily. There is also the problem which has arisen due to the evolution of CAD and CAM. There can be several packages obtained by different departments and thus the need to transfer information between these. As NC users found, standard interfaces like CLDATA are essential to avoid the factorial growth in interfacing programs which would otherwise be needed. All these topics are aired in an unbiased way and these proceedings can be recommended to anyone who has to specify or develop any elements of a system which may need to
Dictionary of computer graphics J Vince, Francis Pinter (Publishers), London (1984) 132 approx A5 pp £15
W H P Leslie
Advanced relational theory The theory of relational databases, David Maler, Computer Science Press (1983) 637pp 428.95
On the dust cover the publisher claims this book to be 'an invaluable aid to student, teacher and professional alike'. However, the author, in the introduction, says that the primary reason for writing it was to describe in layman's terms some of the words and concepts often employed in technical literature. I think that it has turned out that the meagre material in the book would have been more convenient to use if it had been organized in a series of themes with an index to link the terms to the text. As it is, a topic such as colour is dealt with under 12 different entries ranging from 'additive colour' to 'value.' It is really advisable to read all the entries because although there is a lot of duplication of the information under these entries there is no complete description of the way colour is dealt with in computer graphics nor is there an index to lead you to all the entries. A similar problem arises with the references. These are listed under 'colour', 'hidden line removal', 'shading and illumination', modelling' and 'miscellaneous' and are very up to date with the most recent being March 1984. Within each section they are in alphabetical order of author and are not numbered. Where they are referred to in the text there are occasions where all the titles have to be scanned because the name in the text turns out not to be the author's but in the title. For example, the 8 entries in the text about smoothed curves or surfaces mention Bezier and quadric but omit Coon's patches. Coon appears in the references under Forrest in the title of an article. In my'opinion the book is not good value and it would be better to consult a good book on computer graphics with an adequate index.
The purpose of the book, as stated by the author, is to 'give a student sufficient background to read recent papers in relational theory'. In that regard, the book is very successful: it is a most impressive compendium of current topics, along with basic theory in the field of relational databases. It covers the ground customarily explored by most other books dealing with this subject, and it includes additional topics such as the theory of data representation and database semantics, which those books typically mention only briefly, if at all. The material is presented in a well organized, coherent, and notationally standardized manner. Each chapter includes, in addition to theory (which is presented mostly through lemmas and theorems), a clear introductory paragraph, definitions, many examples, and a pertinent bibliography that may facilitate further study of the subject discussed in that chapter. The extensive list of exercises at the end of each chapter will be welcomed by educators who choose the book as a text for an advanced relational database course. In the preface, the author describes the source of the book as notes he wrote for a graduate seminar in relational database theory. Indeed, the graduate student and the professional database research scientist will find the book a comprehensive reference to relational database theory. I suspect, however, that it is much too advanced to be used as a text for an undergraduate course, or for that matter for any readership not already familiar with database theory in general, with set theory, and in particular with relational calculus. The abundant use of examples does not always facilitate the comprehension of the material: it seems like they are used in many cases to introduce new concepts, as much as for illustrating those already discussed.
W H P Leslie
Y Kalay
volume 1 7 number 1 january/february 1985
47