Automatica, Vol. 5, pp. 13-14. Pergamon Press, 1969. Printed in Great Britain.

IFAC Symposium in Israel* A. NIEMH

IN A BEAUTIFUL location on the slopes of Mt. Carmel, above the city of Haifa, the modern Technion, the Israel Institute of Technology offered excellent facilities for the IFAC Symposium on Automatic Control of Natural Resources and Public Utilities in September 1967. The organizing committee, the Israel Committee on Automatic Control, had taken a great care of the arrangements for the Symposium which turned out to be a success- ful 1FAC event.

Of the vast field covered by the title of the Symposium, subjects having a special local impor- tance were emphasized. The final scope is des- cribed by the titles of the sessions:

Computer Control of Water Supply Computer Control of Vehicular Traffic Computer Control of Oil Refineries and Power Stations (2 sessions) Automatic Controlled Telephone Systems (2 sessions) /he local Committee also took care of the selec-

tion of papers of the Symposium which came from all over the world, but it was efficiently assisted by the members of the sponsoring IFAC Applications Committee in solicitation of proper papers.

The number of registered participants was 230, but there was a considerable additional attendance at some sessions consisting of local people with a special interest in the particular field. Some of the authors were absent, and their papers were neither presented nor discussed. Generally, however, pre- prints were available even from these authors and they were included in the Symposium proceedings.

Numerous tours guided the participants or the ladies to sight-seeing or to places of technical interest. An informal contact with the colleagues and the local people was inspired by receptions where the participants were invited by the Mayor of Haifa and by Professor J. Ben Uri who, as the head of the colleagues at Technion, had an important role in the organization of the Symposium.

At the opening session, words of welcome were directed to the participants by Dr. A. Shani who, as the Chairman of the organizing Israel Committee on Automatic Control, had conducted the pre- parations all the way through the hard times preceding the Symposium. The Symposium was

* Received 22 August 1968. t University of Oulu, Finland.

opened and the greetings of the President of IFAC presented by the Past President, Professor J. F. CoMes who also advised the participants to fix their attention to the effective way the natural resources are being utilized in Israel. The opening lecture on the automatic control and scientific research was given by Professor R. Perret.

The optimal management of the water resources is important in districts having considerable seasonal and long-term climatic fluctuations. Thus irrigation is a necessity for the agriculture in many parts of Israel. Interesting contributions from the organizing country were included in the program of the session oll the computer control of water supply. In fact, this session was preceded by a survey paper on the planning approaches to water resources development and utilization in Israel by A. Wiener where he related the simulation of the national water grid and optimal utilization of its different elements. The optimal control of the Sea of Galilee, the main surface reservoir of the local system, dur- ing a flood season was treated separately by O. Levin.

Applications of dynamic programming to the control of water resource system were presented in a paper by R. E. Larson and W. G. Keckler. D. Karmeli, A. Shani and Y. Gadish treated in their joint paper the calculation of the water schedule for an actual agricultural settlement and analyzed different factors having influence on it. They con- sidered that a small special purpose computer for farm irrigation problems would open up new methods of water planning and stimulate the use of more efficient irrigation methods.

In order to preserve the purity of water resources the pollution sources must be controlled. Speak- ing of computer control aspects of an activated sludge treatment plant, E. J. Neugr6schl presented the mathematical model of the process and pro- posed a control scheme based on prediction and past history. Though the practical applications still remain to be made, this interesting paper con- tains a lot of basic information needed for the computer control of the process in question.

Though the importance of the water resources to the power generation was sometimes mentioned, the control problems of power stations as well as of power distribution were principally treated in other sessions. In one of these papers, E. C. Ogbuobiri

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and S. Linke gave an extensive presentation of a unified algorithm for loadflow and economic dis- patch in electric power system. H. Unseld treated control problems of small steam power stations and described the contactless control system with fixed circuitry used for automatic start and shut down at the station of the author's institution. The presentation was illustrated by means of a short film.

It was shown by the paper of W. K. Roots and I. Wilenitz that the temperature control in most electrically heated homes suffers from considerable deficiencies. On the basis of experiments and theoretical analysis they came to the requirements which should be filled in order to attain human comfort, Commercially available thermostats do not meet these requirements and changes in their structure were recommended.

The control of vehicular traffic in towns, and especially the benefits of the computer control, are points of common interest at the moment, and papers had been received from several countries. H. N. Yagoda treated the control of arterial street traffic. He developed a control philosophy for the signal light synchronization in accordance with a smooth flow. Control policies were presented for 7th Avenue in New York City as an example and the calculated results were compared with a policy of the type presently used.

A. Adoram described reasons which had motivated the construction of a special purpose computer for the city of Tel Aviv. In their paper, N. Gartner and J. Ben Uri presented the construc- tion of an electronic digital system and its use for the closed-loop control of traffic. Some ideas were mentioned on extending the degree of control to area control.

G. A. Ferrat6 described a continuous dynamic traffic program generation being applied in Madrid and Barcelona. Requirements that the implementa- tion of such a method involves have lead to the development of a hierarchy system so that the local controllers are directed from special-purpose com- puters which obey the instructions of a dynamically programmed central computer.

The computer control of traffic signals in Heisinki had been completed some weeks before the Sym- posium covering in the first stage 50 intersections. Thus the paper on the traffic-area control in Helsinki by H. K. Salmivaara was of contemporary interest. A set of fixed programs is used which are

switched according to the existing traffic situation.

In the field of the telecommunications a central- ized control and supervision system was required in Israel for the location of the faults, for execution of traffic measurements and for a constant contact with all engineering centres of the network. In their paper, G. K. Lev and A. Even-Chaim described the research made in order to find the most appropriate methods which resulted in the construction of prototypes to simulate the best solution.

There were several papers concerned with pulse methods and computer control in telephone systems. The approach related by M. Ward in his paper on the computer control of telephone ex- change was especially interesting. The use of a multiprocessor computer was described in some detail. A symbolic language had been used for assembling and checking of the exchange programs off line on a normal computer. A standard tele- phone language and the multilevel use of the exchange control computer are still waiting for their time.

The field of the mathematical methods of resource control suffered most because of the absence of authors. Though the texts can be found in the proceedings, the Symposium would have been just a set of sessions on separate subjects for many participants, if there had not been the excellent, unifying survey paper on solving the problem of control of physical and social resources by J. A. Aseltine.

Dr. Aseltine fixed the attention to the systems engineering approach, when problems of trans- portation, water, electric power, health care etc. are to be solved. This approach was used by the author in his joint paper with C. V. Stableford on the application of the techniques of space tech- nology to water resource control.

The crisis law defined by the author gives a limit, after which only systems engineering approach can provide a solution to the problems of resources. The real solution often requires the expenditure of very large sums of money. Thus consideration of such problems includes political as well as physical constraints.

The author considered that IFAC and the control engineers should give their full energy to the solution of the problems of resources. He predicted that future symposia will continue to focus the interest of IFAC on the resource control.