Prof Emer. Benjamin Avi-Itzhak

Operations Research and Optimization

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Overview

In Memoriam: Benjamin Avi-Itzhak (1933–2017)

Professor Emeritus Benjamin Avi-Itzhak—or Benny, as we knew him—was born in Jerusalem in 1933 and passed away in November 2017.

Benny obtained a BSc degree in Mechanical Engineering in 1955, an additional BSc in Industrial Engineering and Management (IE&M) in 1960, an MSc in Operations Research also in 1960, and a PhD in Operations Research, in the area of Queueing Theory, in 1963.

I intentionally list these dates carefully, because it was during this period—the late 1950s and early 1960s—that our faculty of IE&M was born. Moreover, this was the period when IE&M research and teaching began here at the Technion, and when Operations Research first emerged in Israel—a research subject that our country has become a world leader in, both from the theoretical and practical aspects. And this was also the period when research in queueing theory began to flourish, including its applications to systems in communications, computing, production, transportation, and more.

Benny Avi-Itzhak was a pioneer and a leader in all the above-mentioned three new frontiers.

Faculty of Industrial Engineering and Management at Technion. Benny was one of the founding fathers of our faculty. He served twice as faculty dean, and had a large impact on the faculty’s character and development—an impact that can still be clearly felt today.

Operations Research. Over many years, Benny maintained a wide range of research interests in the field of operations research, across a unique combination of theoretical studies, applied work, and scientific consulting (for example, on models of energy consumption, oil and gas mining, and transportation planning). He collaborated with the most prominent scholars in the world, such as George Dantzig at Stanford (the father of linear programming), and Conway, Maxwell, and Miller at Cornell (among the founders of discrete event simulation as a research area).

He also supervised ample students, many of whom went on to become extremely successful in their various fields of expertise. These include the late Prof. Yigal Adiri, whom we mourned here only recently, and who was Benny’s doctoral student on the subject of time-sharing systems; and Dr. Yossi Vardi, one of the founders and gurus of Israel’s startup industry and a close friend of the Technion, whom Benny supervised on the subject of electric energy (they actually wrote a book on the subject).

Benny was a member of Israel’s Council for Higher Education, and a member of various government committees and boards of trustees. He was the chief scientist of the Israel Institute of Productivity in Labor and Production, and chairman of the research committee of the Israeli Institute of Shipping and Aviation Research. Benny was one of the founders of the Operations Research Society of Israel (ORSIS), and for many years was a pillar of the Society. To wit, Benny led ORSIS after the untimely passing of Prof. Pinchas Naor—the founder of our faculty—who was in fact Benny’s PhD adviser. Benny invested great efforts in founding and developing the Society, and the logo he designed and the regulations he crafted are still serving us. He was active in the Society and its conferences for many years, and helped secure funding for many of its activities (for example, funds for prizes awarded in memory of ORSIS members who died in wars). Thanks to Benny, our faculty has always served as a welcoming home for ORSIS and its administration, and it was only fitting that ORSIS awarded Benny a lifetime achievement award in 2010.

Queueing Theory. For more than 50 years, Benny was an active researcher who contributed widely to many diverse areas of study. Still, the focus and passion of his research was Queueing Theory. This is a branch of mathematics and engineering that was born at the beginning of the 20th century, and flourished during the 1960s and 1970s precisely thanks to researchers like Benny and his collaborators. Queueing theory is concerned with systems where customers wait their turn for service, usually in a queue that arises due to limited service resources (servers). Typically, Queueing Theory addresses questions such as how many servers are required so that customers will not wait too long; or how much longer do lower-priority customers wait relative to higher-priority.

Benny analyzed diverse models of queueing systems. Examples include queues with various priority schemes; systems with service resources (servers) that go on vacation (e.g. become dysfunctional); systems with queues of limited size; time-sharing and processor-sharing protocols; networks of queues; blocking mechanisms; and more. His research clearly demonstrated his creativity, depth, and analytical strength. These were combined with his ability to transform complex systems into analyzable mathematical models, and to use these models to gain insights that led to significant improvements in the functioning of their originating systems.

In recent years, Benny’s research mainly focused on fairness in queueing, on which he collaborated with Prof. Hanoch Levy (who now heads Tel Aviv University’s School of Computer Science). Fairness is a central attribute of queueing systems (and of course, of other systems as well); yet oddly this subject has scarcely been studied, over many decades of research. For example, an elementary question that has not been properly asked and for which no scientific answer has been attained, is as follows: Is it fair that a customer with a single product be served at a supermarket checkout prior to a customer with a full shopping cart who arrived at the checkout first? Benny’s research investigated ways in which fairness in queues can be quantified, and he attempted to develop fairness indices that could be used to assess various queueing systems, to quantify their level of fairness, and thus to compare various queueing policies according to their level of fairness.

Of all Benny’s outstanding qualities, three stand out: He had a brilliant mind, he was a person of great wisdom and he was a born leader. Thus, it was only natural that he was a sought-after and popular visiting scholar at the leading programs of Operations Research world-wide (e.g. Cornell, Stanford, Case Western, Bell Labs).

In the 1990s, health issues forced Benny to relocate to the United States. He retired from the Technion and moved to Rutgers University, where he served as head of the Operations Research Center and as a department head at the Rutgers Business School. Despite the distance, Benny managed to keep in close and permanent contact with his friends and research partners in Israel.

Allow me to conclude with a Technion tale, which I learned from Prof. Michael Rubinovitch, a close friend of Benny and his family. In the eulogy he delivered at Benny’s funeral, Prof. Rubinovitch related a story concerning a Technion senate meeting held in the 1960s. The legend then tells that the late Prof. Moshe Zakai, who was a world-renowned probability scholar, expressed his doubts concerning the level of probability research at our IE&M faculty. (Let me assure you that no one entertains such doubts today.) Benny, who was a dean and senate member at the age of 36, told Zakai that he had been wrong and offered to prove it. “Let’s do the following:” he said. “You will ask me a question in probability, and then I shall ask you a question in probability, and so on and so forth.” Prof. Rubinovitch did not know if this was what really happened, or whether this challenge ever took place, but the story is a perfect demonstration of Benny at his best: intelligent, self-confident, uncompromising, and unwilling to back down. He was a true leader who knew very well how to present and argue for what he believed in, but was at the same time always polite, generous, and respectful.

Benny is survived by his wife, Dr. Tamar Avi-Itzhak, and his two children, Carmel and Hadar.

May his memory be blessed.

Dean of the Faculty of Industrial Engineering & Management, Technion.

Research

Stochastic Models, Queueing Theory, Telecommunication Systems, Supply Chain Management, Electric Power Generation and Distribution, Shipping and Transportation.