- Email: [email protected]
International symposium on circuits and systems
V. Morregia described how it: is used in the production of engineering drawings. The CAD Centre has developed a c.a.d, approach to the design of mechanical engineering components. A simple numerical description of the component is held centrally in datastructures. The structure can be output in formats to meet the aser's requirements, including n.c. tapes.
Design linked to manufacture Design is an activity which supplies information to other activities in the total process of manufacture. C.a.d. will be most viable if it takes into account where the information goes and in what form it will be most useful. M. Sabin, Kongsberg Ltd., t o o k an overview of the introduction and use of c.a.d, pointing out the pitfalls and the interaction of design with each phase in the lifetime of a product. Three means of geometric design were given b y speakers frora British Aircraft Corp, Hawker Siddeley, and the CAD Centre. These papers clearly show the emphasis towards using graphics in c.a.d.-c.a.m, systems. A problem faced b y both the garment industry and in shipbuilding is that of obtaining an o p t i m u m layout of parts to minimize waste. U. Cugini, Politecnico di Milano, outlined a c.a.d. system for pattern grading and marker making in the garment industry. J. Oian described a system for nesting production parts for shipyards using the Autokon 71/74 system. The system uses interactive graphics to help nest plane parts on a raw steel format.
Social aspects of CAD There is a clear need to make computers responsive to human needs and achieve a better integration of complex industrial processes. This was the message delivered b y A. Llewelyn, CAD Centre, chairing the social implications session. The key to this integration lies in the approach taken to software design. Design systems to match human skills and provide not solutions but tools to allow people to work in a manner of their choosing suited to their environment. Improved visualization allows both customer and community to participate. We need to reverse our usual attitude and think of hardware as ephemeral and software, because of its much higher value, in all senses, as lasting for a much longer time. This means that the software must be more complex in order to be easy to use. More attention must be paid to the objectives and less to the organizational form of the maze of interlocking committees which stifle progress. The Trade Union viewpoint on c.a.d. was given by the loquacious Mike Cooley, former President of the Amalgamated Union of Engineering Workers. A lack of concern for human needs in developing c.a.d, systems will lead to shift work and overtime to reduce the computers 'downtime'; redundancy as the introduction of CAD changes the design activity from a labour intensive activity to a capital intensive one; the information explosion brings in its wake knowledge obsolescence - a major problem for older workers; mental stress and visual fatigue caused by
lengthy periods of working with a graphic screen; the scientific management of c.a.d, to reduce the human being to the requirements of the computer. Mike Cooley brought out many valid points that all those embarking on any c.a.d, development should consider carefully. His deep anxiety was not shared by all the audience. Tom Mayer, ABACUS, spoke of democracy in design decision-making. He criticized the 'dynamic conservatism' advocated by Mike Cooley and believes that a new philosophy of design is being formulated, which with the help of the computer could make participatory democracy a reality within a high technology society. Tom Mayer raised two important questions in anticipation of the future of c.a.d.: Do we accept the overriding professional responsibility to bring about a state of affairs in which the profession as we know it is no longer needed or do wo close the ranks in our professional institutions and Trade Unions to maintain the status and power of the designer as we currently know it.
CAD 78 The third international conference and exhibition on computers in engineering and building design will review developments and applications b y both practitioners and academics. It will be held at the Brighton Metropole to ensure that discussions can continue in the evening. All facilities - conference and exhibition halls, restaurant, bars will be close together. CAD 78 will be held on 1 4 - 1 6 March 1978.
International symposium on circuits and systems April 2 7 - 2 9 1976. Technical University, Munich, F. R., Germany.
This conference is traditionally the highlight of the year in the field of circuits and systems, and this reputation was not to be challenged this year. In fact, all previous records were broken, with the number of papers totalling 200, and 5!)9 participants drawn from over 30 countries.
Volume 8 Number 4 October 1976
The contents of the conference reflect the current trends in the subject area. In general, there were six parallel sessions running simultaneously and these included microwave networks, RC-active filters, symbolic analysis, digital filters, computer-aided design, A/D and D/A convertors, topology, computer-aided
methods for layout and wiring, recent advances in optimization; simulation, identification and modelling; SAW devices and applications, large scale systems, system theory and design, nonlinear networks and systems, passive networks and mechanical filters. It is obviously not possible to report on all the sessions but a sampled view may provoke interest in the proceedings as a whole. In the first c.a.d, session, the problem of d.c. analysis of electron-
281
ic circuits was tackled by a group of authors from IBM, and S.W. Director outlined the optimization of forced nonlinear periodic circuits. A session on symbolic analysis included work by J. Vlach and K. Singhal on a new approach for analogue and digital circuits, an alternative technique was outlined b y F. Wehrahn. Partition methods applicable to this work were presented by C. Phrydas and J. I. Sewell. Further sessions on the application of computer methods covered a new method for numerical inversion of Laplace transforms b y A. Talbot. R. Spence discussed problems of interactive-graphic mancomputer dialogue in circuit design. The problems associated with manipulation of sparse matrices received considerable attention in two papers given b y O. Wing, a paper b y J. Jess and another by N. B. Rabbat and H. Y. Hsieh. Statistical and tolerance problems in circuit manufacture and their solution by computer means were covered by a series of papers b y C. A. Desoer and F. Lo. Ka-Ho Leung and R. Spence, V. Beres and K. Geher, N. Fliege, G. Muller, M. Glesner, K. Haubricks and H. J. Leineler. A session on computer-aided methods for layout and wiring included six papers contributed mainly b y German and Japanese companies directly involved in solving such problems for manufacturing
processes. Other sessions connected with computer technique considered the analysis of nonlinear circuits and systems, together with the analysis of communication systems. Recent advances in optimisation were outlined in papers b y J. W. Bandler, H. L. Abdel-Malek, P. B. Johns and M. R. N. Rizk; A. J. Jiminez and S. W. Director; K. Masden and H. SchjaerJacobsen; J; H. Pinel, F. Brglez, W. Chu and O. Monkewich; and G. C. Temes. These contributions were particularly orientated to circuit problems but an application to the design of digital filters was included. A large number of papers on the subject of digital filters were included in the conference, which is to be expected considering the emphasis that has been placed on this subject area in German research during the last few years. In fact in addition to the conference, a workshop on digital filtering was organized for the whole day preceding the formal proceedings. A t the end of the symposium, two half-day tutorials by H. W. Schussler and A. Fettweis on the design of digital filters, provided a fitting conclusion to this section of the programme. The other major subject area was active filters, and in seven sessions, a multitude of topics were covered. Papers on the use of gyrators and FDNR's provided a start in session one. Numerous authors considered the sensitivity problem in these circuits; other factors studied were the feasibility of active-R filters, minimization of the number of capacitors and the effects of
noise performance. Various new canonic building sections were outlined and their comparative performances with existing circuits described. A session on classical networks provided an opportunity for a number of authors to demonstrate some superb extensions and applications of equivalent network theory to passive networks. Two papers by V. Tavsanoglu were concerned with transformation in Cauer and Foster forms. H. K. Kim and A. Ali described the application of these theories to the minimization of various cost functions (element spread andsize) in RC ladder networks. A fundamental problem with equivalence transformations is the generation of an excessive number of new elements, a paper by W. Ulbrich tackled this and produced a neat solution, he also introduced an interesting concept of seed-point transformations. A paper in an active filter session by L. G. Grant and J. I. Sewell provided a suitable complement to the ones mentioned. They described how the difficulties of applying-equivalence transformations to active networks have been overcome and showed how existing active filter circuits can be optimized with respect to component spread and size. A symposium which gathered together the majority of the appropriate active researchers of the world and organized with teutonic efficiency could hardly fail to produce a resounding success.
j. L Sewell University of Hull, UK
PROLAMAT '76 15th-18th June 1976. University of Stirling, UK The Third IFIP-IFAC International Conference on Programming Languages for Numerically Controlled Machine Tools attracted over 150 delegates from 19 countries. Some of the papers presented reflected a consolidation of the more familiar areas such as computer-aided n.c. programming, shape description and curved surface generation. The current move towards large integrated c.a.d.-c.a.m. systems and the technology required to design and exploit them effectively was also apparent.
282
The conference was formally opened b y Sir John Toothill, formerly Director Ferranti Ltd., who reviewed the considerable progress which had been made in the application of computers to design and manufacturing processes during the past two decades. The conference began with two invited papers. The first, presented by H. Yoshikawa, T o k y o University, described the background philosophy and the progress of the Japanese Automated F a c t o r y Project. The requirement to develop a highly efficient,
economic yet socially acceptable manufacturing facility had led to the construction of the fully automated unmanned machine shop. This type of facility could only be afforded by a few enterprises but the modular approach would allow other users to benefit from the development.-',. The ~aigh priority which the Japanese Government has placed its mechanical engineering industry over other industries more expensive in energy and land resources, was emphasized by the $30 M grant provided to produce the prototype factory. The second paper was the first of a group of excellent and timely contri-
COMPUTER AIDED DESIGN
Design linked to manufacture Design is an activity which supplies information to other activities in the total process of manufacture. C.a.d. will be most viable if it takes into account where the information goes and in what form it will be most useful. M. Sabin, Kongsberg Ltd., t o o k an overview of the introduction and use of c.a.d, pointing out the pitfalls and the interaction of design with each phase in the lifetime of a product. Three means of geometric design were given b y speakers frora British Aircraft Corp, Hawker Siddeley, and the CAD Centre. These papers clearly show the emphasis towards using graphics in c.a.d.-c.a.m, systems. A problem faced b y both the garment industry and in shipbuilding is that of obtaining an o p t i m u m layout of parts to minimize waste. U. Cugini, Politecnico di Milano, outlined a c.a.d. system for pattern grading and marker making in the garment industry. J. Oian described a system for nesting production parts for shipyards using the Autokon 71/74 system. The system uses interactive graphics to help nest plane parts on a raw steel format.
Social aspects of CAD There is a clear need to make computers responsive to human needs and achieve a better integration of complex industrial processes. This was the message delivered b y A. Llewelyn, CAD Centre, chairing the social implications session. The key to this integration lies in the approach taken to software design. Design systems to match human skills and provide not solutions but tools to allow people to work in a manner of their choosing suited to their environment. Improved visualization allows both customer and community to participate. We need to reverse our usual attitude and think of hardware as ephemeral and software, because of its much higher value, in all senses, as lasting for a much longer time. This means that the software must be more complex in order to be easy to use. More attention must be paid to the objectives and less to the organizational form of the maze of interlocking committees which stifle progress. The Trade Union viewpoint on c.a.d. was given by the loquacious Mike Cooley, former President of the Amalgamated Union of Engineering Workers. A lack of concern for human needs in developing c.a.d, systems will lead to shift work and overtime to reduce the computers 'downtime'; redundancy as the introduction of CAD changes the design activity from a labour intensive activity to a capital intensive one; the information explosion brings in its wake knowledge obsolescence - a major problem for older workers; mental stress and visual fatigue caused by
lengthy periods of working with a graphic screen; the scientific management of c.a.d, to reduce the human being to the requirements of the computer. Mike Cooley brought out many valid points that all those embarking on any c.a.d, development should consider carefully. His deep anxiety was not shared by all the audience. Tom Mayer, ABACUS, spoke of democracy in design decision-making. He criticized the 'dynamic conservatism' advocated by Mike Cooley and believes that a new philosophy of design is being formulated, which with the help of the computer could make participatory democracy a reality within a high technology society. Tom Mayer raised two important questions in anticipation of the future of c.a.d.: Do we accept the overriding professional responsibility to bring about a state of affairs in which the profession as we know it is no longer needed or do wo close the ranks in our professional institutions and Trade Unions to maintain the status and power of the designer as we currently know it.
CAD 78 The third international conference and exhibition on computers in engineering and building design will review developments and applications b y both practitioners and academics. It will be held at the Brighton Metropole to ensure that discussions can continue in the evening. All facilities - conference and exhibition halls, restaurant, bars will be close together. CAD 78 will be held on 1 4 - 1 6 March 1978.
International symposium on circuits and systems April 2 7 - 2 9 1976. Technical University, Munich, F. R., Germany.
This conference is traditionally the highlight of the year in the field of circuits and systems, and this reputation was not to be challenged this year. In fact, all previous records were broken, with the number of papers totalling 200, and 5!)9 participants drawn from over 30 countries.
Volume 8 Number 4 October 1976
The contents of the conference reflect the current trends in the subject area. In general, there were six parallel sessions running simultaneously and these included microwave networks, RC-active filters, symbolic analysis, digital filters, computer-aided design, A/D and D/A convertors, topology, computer-aided
methods for layout and wiring, recent advances in optimization; simulation, identification and modelling; SAW devices and applications, large scale systems, system theory and design, nonlinear networks and systems, passive networks and mechanical filters. It is obviously not possible to report on all the sessions but a sampled view may provoke interest in the proceedings as a whole. In the first c.a.d, session, the problem of d.c. analysis of electron-
281
ic circuits was tackled by a group of authors from IBM, and S.W. Director outlined the optimization of forced nonlinear periodic circuits. A session on symbolic analysis included work by J. Vlach and K. Singhal on a new approach for analogue and digital circuits, an alternative technique was outlined b y F. Wehrahn. Partition methods applicable to this work were presented by C. Phrydas and J. I. Sewell. Further sessions on the application of computer methods covered a new method for numerical inversion of Laplace transforms b y A. Talbot. R. Spence discussed problems of interactive-graphic mancomputer dialogue in circuit design. The problems associated with manipulation of sparse matrices received considerable attention in two papers given b y O. Wing, a paper b y J. Jess and another by N. B. Rabbat and H. Y. Hsieh. Statistical and tolerance problems in circuit manufacture and their solution by computer means were covered by a series of papers b y C. A. Desoer and F. Lo. Ka-Ho Leung and R. Spence, V. Beres and K. Geher, N. Fliege, G. Muller, M. Glesner, K. Haubricks and H. J. Leineler. A session on computer-aided methods for layout and wiring included six papers contributed mainly b y German and Japanese companies directly involved in solving such problems for manufacturing
processes. Other sessions connected with computer technique considered the analysis of nonlinear circuits and systems, together with the analysis of communication systems. Recent advances in optimisation were outlined in papers b y J. W. Bandler, H. L. Abdel-Malek, P. B. Johns and M. R. N. Rizk; A. J. Jiminez and S. W. Director; K. Masden and H. SchjaerJacobsen; J; H. Pinel, F. Brglez, W. Chu and O. Monkewich; and G. C. Temes. These contributions were particularly orientated to circuit problems but an application to the design of digital filters was included. A large number of papers on the subject of digital filters were included in the conference, which is to be expected considering the emphasis that has been placed on this subject area in German research during the last few years. In fact in addition to the conference, a workshop on digital filtering was organized for the whole day preceding the formal proceedings. A t the end of the symposium, two half-day tutorials by H. W. Schussler and A. Fettweis on the design of digital filters, provided a fitting conclusion to this section of the programme. The other major subject area was active filters, and in seven sessions, a multitude of topics were covered. Papers on the use of gyrators and FDNR's provided a start in session one. Numerous authors considered the sensitivity problem in these circuits; other factors studied were the feasibility of active-R filters, minimization of the number of capacitors and the effects of
noise performance. Various new canonic building sections were outlined and their comparative performances with existing circuits described. A session on classical networks provided an opportunity for a number of authors to demonstrate some superb extensions and applications of equivalent network theory to passive networks. Two papers by V. Tavsanoglu were concerned with transformation in Cauer and Foster forms. H. K. Kim and A. Ali described the application of these theories to the minimization of various cost functions (element spread andsize) in RC ladder networks. A fundamental problem with equivalence transformations is the generation of an excessive number of new elements, a paper by W. Ulbrich tackled this and produced a neat solution, he also introduced an interesting concept of seed-point transformations. A paper in an active filter session by L. G. Grant and J. I. Sewell provided a suitable complement to the ones mentioned. They described how the difficulties of applying-equivalence transformations to active networks have been overcome and showed how existing active filter circuits can be optimized with respect to component spread and size. A symposium which gathered together the majority of the appropriate active researchers of the world and organized with teutonic efficiency could hardly fail to produce a resounding success.
j. L Sewell University of Hull, UK
PROLAMAT '76 15th-18th June 1976. University of Stirling, UK The Third IFIP-IFAC International Conference on Programming Languages for Numerically Controlled Machine Tools attracted over 150 delegates from 19 countries. Some of the papers presented reflected a consolidation of the more familiar areas such as computer-aided n.c. programming, shape description and curved surface generation. The current move towards large integrated c.a.d.-c.a.m. systems and the technology required to design and exploit them effectively was also apparent.
282
The conference was formally opened b y Sir John Toothill, formerly Director Ferranti Ltd., who reviewed the considerable progress which had been made in the application of computers to design and manufacturing processes during the past two decades. The conference began with two invited papers. The first, presented by H. Yoshikawa, T o k y o University, described the background philosophy and the progress of the Japanese Automated F a c t o r y Project. The requirement to develop a highly efficient,
economic yet socially acceptable manufacturing facility had led to the construction of the fully automated unmanned machine shop. This type of facility could only be afforded by a few enterprises but the modular approach would allow other users to benefit from the development.-',. The ~aigh priority which the Japanese Government has placed its mechanical engineering industry over other industries more expensive in energy and land resources, was emphasized by the $30 M grant provided to produce the prototype factory. The second paper was the first of a group of excellent and timely contri-
COMPUTER AIDED DESIGN