Books the reader is left to establish the relationship between the alternative approaches to 2D geometry input of CASUS and PICME SKETCH). Nevertheless, even without establishing the precise degree of integration between modules, each description is interesting in its own right. For example, the methods used to allow updating of dimensions of a 2D projection of a 3D model, following modifications to the 3D model, are a partial solution to a long-standing problem in integration of 2D and 3D techniques. It is good to see 30 pages devoted to 'technological planning'. This function, the 'design' of the manufacturing process, is emerging as a crucial component of a 'Computer integrated manufacturing' system. Several planning systems were developed under APS. One empha-
sizes automatic generation of plans based on design models annotated with 'technological elements'. Another covers interactive planning, giving a user access to sufficient company-specific data to produce plans appropriate to the company' s manufacturing facilities. As well as these applications, the 'systems' level results of APS are described. My reaction to the graphics and database items here was essentially uninspired ('oh another one'). However, the section on Product information systems demonstrates the kinds of complexity required with a believable simple example and concludes that commercially available database systems 'are not fast enough'. If true, this result is important. The second half of the book
covers industrial implementations of APS results. There is an unavoidable overlap with items in the first half of the book, which leads to the slightly uncomfortable feeling of d~j~ vu while reading. Each product description is considerably more useful than the typical product information brochure available from the vendor, as background to the development, examples of installation, and indications of future trends are included, as well as lists of product capabilities. Overall, I think this is a good book primarily suitable for technical and nontechnical people involved in large scale CADCAM system development, either as vendors or end users.
P Thorne
Useful companion for 'old fashioned' designers Prestressed concrete design by computer R Hulse and W H Mosley McMillan (1987) 136 pp £20.00 (hardback) £8.95 (paperback)
The day-to-day design calculations that take place in the civil engineer's office could be a tedious, unenjoyable task that one would have thought the electronic computer by now should have taken over completely. Not so. The old generation of these professionals are especially conservative and take their own time to adapt to modern trends. This text thus comes as a relief and could become the designer' s companion. Quite discretely, the book separates analytical and design procedures and in the last chapter shows how the two can be linked by Chaining. As a demonstration text, this is quite acceptable, but in practice the analytical output should map into the design program while ensuring that the designer still has an interactive inspectory role to play during the execution of the
volume 20 number 7 september 1988
unified program. The computer programs that appear in the book are written in Basic. These programs are simple and clear and made easy to understand by the provision of flowcharts whose bounds correspond to statement numbers in the programs. These provisions enable the reader to follow the programs very well. Well, will anyone disagree why such a serious subject is presented in Basic? If you are looking for near perfection, you could suggest Pascal. The painful fact, however, is that despite its bulk and several annoying features. Fortran has managed to become the engineer's language and so much of the engineer's software is already available in Fortran that it will not be easy for any other high-level language to reach the same acceptability. Although it is not indicated whom the book is intended for, it may fail to tempt the young talented graduate student who is out for challenging innovative programming ideas, but the book will surely be a
companion to the practical, even if old fashioned, engineer who is seeking some relief from daily office design chores. Some of the very useful programs that appear in the book are: elastic analysis and design, calculations for prestressed deflections and losses and design for shear. Quite naturally, these design programs satisfy limit state criteria as outlined in BS 8110. But what are data variables and program variables? This terminology used throughout the book creates confusion. For instance, section moduli ZB, ZT are called program variables in one program and data variables in another[ Prestressing is still a very active construction technique and very popular in both precast and in situ concrete construction. Those designing such structures will find the programs in the book useful at a reasonable price of £8.95 for the paperback edition. But first, they must read the disclaimer! K Andam
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