Bulletin 102, April 98 
EURO
The Association of
European Operational Research Societies
within IFORS
  
Report on the EURO Summer Institute in Saint-Vincent (Italy)

Every year, the association of European operational research societies within IFORS (EURO) organizes a EURO Summer Institute (ESI) in order to make young researchers come together. The participants (of less than 35 years old) come from different European countries and are selected by their national OR society. The accommodation and registration are taken in charge by the organizers of the Institute, a part of the money needed being provided by EURO. Each ESI has its theme and every participant presents a research paper on a topic within this theme. Moreover, lectures by invited experts are organized. In order to facilitate the network building among the participants, a varied social program is usually prepared by the organizers.

I was the Swiss participant at the 15th Euro Summer Institute that was held in Saint Vincent, a village in the beautiful Aosta Valley (Italy), from September 12 to 26, 1997. Its theme was "Production scheduling: Deterministic, Stochastic and Fuzzy Approches" and the chairman of the organising committee was Prof. Roberto Tadei from the Politecnico di Torino. He was also the organizer of AIRO97, the meeting of the Italian association of Operational Research, which was held in the same village, September 16-19. The program of the ESI was prepared such that the participants could follow the different sessions of AIRO97, some of them being dedicated to scheduling, manufacturing, production management, …. Unfortunately, the presentations were very often done in Italian and could not be followed by most of the ESI participants. We were 14 young scientists (about one third were Ph.Ds), representing 12 different countries: Belarus, Croatia, Germany, Great-Britain, Israel, Italy, the Netherlands, Norway, Portugal, Sweden, Switzerland and Turkey.

After a welcome party on Friday 12th, we made some excursions and visits during the week-end that allowed us both to discover the region (there are numerous medieval castles in this valley) and to strike up an acquaintance with the different participants. Therefore we already knew each other a little bit when the presentations began on Monday. During the two weeks we could follow numerous very interesting presentations, both from the participants and from the lecturers (there were 13 of them). Interesting discussions also occured during the breaks or during the hours spend at the table, eating the good meals the kitchen of the Hotel Elena, where we stayed, prepared us every day. The one-hour presentations covered different sorts of problems, including production planning, lotsizing, multiobjective project scheduling and single machine scheduling. The title of my talk was "Operational Production Planning and Inventory Management: A Case Study in the Medical Device Industry", based on a work I did with Philippe Solot and John Golby. A special issue of EJOR will be prepared based on papers presented.

A very nice banquet in a perfect atmosphere concluded this Summer Institute. Without any doubt, thank to the perfect organization, every participant  has taken profit of these two weeks, both from a scientific point of view and from the point of view of the created contacts. We are all looking forward to the next conference were we can meet again.

I am grateful to ASRO/SVOR for having given me the opportunity to go to this ESI and strongly recommend everyone to apply for a future Institute (maybe in Switzerland?). The next one is held in Warwick (UK), from August 16 to 26, 1998.
 
 
Daniel Kobler
daniel.kobler@epfl.ch
 

 
Report on the 3ème Cycle Romand de Recherche opérationnelle,
Zinal, March 1-5, 1998
 
Combinatorial models in manufacturing,
Markov Decision Processes,
Polytime separation implies polytime optimization
 
The seminar organized each year by the "3ème Cycle Romand de Recherche Opérationnelle" took place in the peaceful village of Zinal. The 32 participants coming from EPFs Lausanne and Zürich, the Universities of Fribourg and Genève, and also from IDSIA (Lugano) attended this spring seminar. Three invited speakers have presented recent research results. These speakers were : Gerd Finke talked about the socalled robotic cell scheduling problem. He presented a new unifying theory for periodic production cycles and pyramidal permutation schedules and settle completely the 10-year old one-cycle conjecture. He also presented many interesting results dealing with the two principal categories of transportation systems : the uni-directional movements of for instance automated guided vehicles and the bi-directional movements of a robot arm. In the case, he compared the usual event-driven strategies for the traffic control with a purely combinatorial global algorithmic approach.

Martin L. Putermann introduced Markov decision processes (MDPs) through description of their formulation, applications, computational methods and theoretical issues. Then he explored the relationship between three MDP optimality criteria; bias optimality, average optimality and expected total re ward optimality. It showed that an obvious policy iteration algorithm may fail to find optimal policies under the expected total reward criterion and how a nested policy iteration algorithms which find bias optimal policies can be used to solve MDPs under the expected total reward criterion.

The third lecturer, Jean-François Maurras, has tried to convince the audience that "separation and optimization are polynomially equivalent". He has used the works of L.G. Khachiyan (1979) and of A.K. Lenstra, H.W. Lenstra Jr and L. Lovasz (1982) and has developped a huge amount of theorems, propositions and corollaries to prove this interesting result.

We had the opportunity to get an insight into some of our students' and colleagues' research fields. The talks of about 20 minutes dealt with various subjects such as shift scheduling, stochastic programming, optimisation techniques in computer animation, TSP, column generation and hybrid production systems.

Despite a heavy program we were able to have fruitful discussions and make interesting contacts. The dinners were privileged moments of discussion in a relaxed atmosphere. A good scheduling allowed us to enjoy the sunny (?) weather on the ski slopes which gave us a well appreciated break between the talks.

We would like to thank the organizer, Professor Alain Haurie (University of Genève), the invited speakers, the sponsor "3ème Cycle Romand de Recherche opérationnelle " as well as the ASRO/SVOR for their support.
 
 
Marino Widmer
marino.widmer@unifr.ch
  

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