Igal Adiri

Professor Emeritus Igal Adiri was a faculty member at the Technion’s Faculty of Industrial Engineering and Management from 1963 onward, working in the field of Operations Research. He specialized in the analytical and applied aspects of two main research  subjects:

Queueing theory

Deterministic and stochastic scheduling theory

Igal was one of the first researchers to apply queueing theory to the modeling of computer operating systems. He was also the first to introduce scheduling theory, with its various aspects, to operations research and industrial engineering in Israel.

Igal educated generations of students who can now be found in key positions in many areas of the Israeli economy.

Professor Igal Adiri gained a BSc in electrical engineering in 1958, an Msc in operations research in 1965, and a PHD in 1967, under the guidance of Professor Binyamin Avi-Yitzhak. He obtained all of his degrees at the Technion.

Although Igal came from the field of electrical engineering, and specialized in its theoretical aspects, he recognized the importance of applications for the field of industrial engineering. In his academic work—both research and teaching—he thus concentrated on the applied side.

He wrote his doctorate on what we now call queueing theory. This is the mathematical theory of systems in which costumers wait for service, generally due to there being limited resources available. His earliest research was into time-sharing queues, and he then advanced to analyze priority-based queues, mainly static ones. In the 1980s, alongside his continued research into priority systems, he also educated himself in the field of scheduling theory.

His articles were published in the most prestigious journals, and the collection of his articles published before he became ill is simply outstanding.

Igal had many students: around 15 MSc students and three PHD students. Igal invested a lot of time in his students and was well known as an excellent supervisor, a superb teacher, and person of great integrity and fairness. He developed teaching notes on queueing theory, scheduling, and stochastic models, which were frequently used by many members of the faculty in their teaching.

Igal was always an excellent teacher, for which he received widespread recognition and teaching prizes. It was always important for him to carry on teaching even when he was sick, confined to a wheelchair; to this end he developed customized methods that allowed him to continue to excel in his teaching.

Igal Adiri was a member of the founding generation of the field of operations research in Israel. During the 1960s and 1970s, he delivered a lecture series in Israel titled “What is Operations Research?” These lectures attracted many students and researchers to join this field, and subsequently to lead it, both in Israel and internationally. Thus, Israel became a global power in operations research, thanks to Igal and other researchers like him.

Igal was a special person, and a special scholar. One story concerns two leading researchers from the Netherlands, J. K. Lenstra and A. H. G. Rinnooy Kan, who announced that they would award a personal gift of a chocolate windmill to anyone who could find the solution to a particular problem in combinatorics that they had been unable to solve. Igal, together with his student Dr. Nava Hefetz (now Izikovitch), solved the problem, which led to Lenstra and Rinnooy Kan making a visit to the Technion. They couldn’t bring the windmill, and instead brought a box of candies and a ceramic tile with a picture of a windmill. Igal, who by then was in a wheelchair, hosted them, together with Professor Aharon Ben-Tal, in a visit that will be remembered to this day by many.

May his memory be blessed.