Now that we settled (or not settled) the issue whether or not I am a maritime economist (see HERE), comes a similar question: am I an operations researcher?
Below is some related material.
The trigger for this discussion has been the recent (circa 20.03.2025) podcast of Anand Subramaniam, a colleague in Brazil, in which he interviewed me on my professional career, from an operations research (OR) perspective. In the podcast I also talked about some aspects of my personal life, and references were also made to Pele, the Olympiacos football team, the Rolling Stones, the Boston Celtics, and Claude Monet. See HERE for that podcast. I am grateful to Anand for this interview and I want to commend him for his overall effort, to interview more than 100 OR people.
So here is the story:
My first (undergraduate) studies were at NTUA, where I got a diploma in naval architecture and marine engineering (NA&ME). No OR here.
I first became aware of OR when I went for graduate studies at MIT in 1974, and I did not go to MIT to study OR. I went to MIT (dept. of ocean engineering) to get a dual MSc degree in NA&ME (see above) and in shipping and shipbuilding management (S&SM). A common thesis was planned for these two degrees.
It was during the course of the S&SM curriculum that I took some classes that had a strong OR content. These included probability, mathematical programming, and operations management. This is when I started developing an interest in OR, and it was then that I realized that MIT had the so-called OR Center, an interdepartmental OR program with faculty coming from many MIT departments.
However, I could not just switch to OR, as I did not have financial support in that area (I was working as a research assistant in ocean engineering). The breakthrough came in late 1976, and before I finished my MSc program, when Amedeo Odoni, a professor in the aeronautics and astronautics department (and also in civil engineering) offered me a research assistantship to work for him on some vehicle routing problems, effective summer of 1977. This would be for my PhD.
I made the switch with a lot of excitement, but also stress. I still remember when I bought Hillier and Lieberman's "Introduction to Operations Research", how exhilarated I was that I was entering this field. But at the same time I was quite apprehensive on whether I would succeed. It was a big jump that I had decided to take, and how exactly I would land (and where) was not clear.
Just as I was starting my PhD work (summer of 1977), I attended the EURO/TIMS International Conference that took place (of all places) in Athens, Greece. This was my first OR conference (I didn't give a paper). I remember a session on mathematical programming chaired by Marshall Fisher, an expert on vehicle routing whom I would get to know better several years later, when I was a faculty member at MIT. Speakers in the session included Nicos Christofides, Egon Balas and George Nemhauser. At that session in Athens, I was in awe of these and other OR heavyweights.
The fall term of 1977 was one of the most productive of my entire student life. I made most of the progress during my PhD during that term, and I really enjoyed it. I produced a dynamic programming algorithm for the aircraft sequencing problem with maximum position shift constraints, a problem that was solved only heuristically so far. Then I produced a similar algorithm for the dial-a-ride problem, a problem in urban transportation. Mind you, I did this while I was still a student in the ocean engineering department. I defended my PhD in the fall of 1978 and I received my PhD degree in May 1979. This PhD thesis won the so-called “dissertation prize”, an award sponsored by the Transportation Science Section of ORSA (the Operations Research Society of America). ORSA & TIMS were the precursors of INFORMS.
I received the award at the ORSA meeting in Milwaukee, fall of 1979. The picture below is from the award ceremony. Also shown are John Little (left), then President of ORSA, and Richard Rothery, then Editor-in-Chief of Transportation Science. (I am not the only one with a beard in the pic).
Another picture shows a box that has all my PhD thesis in it. Complete with handwritten text, supervisor's comments, computer runs, typewritten original, the works. The thesis was typed (not by me, but by a secretary) on an IBM Selectric typewriter. There was no word processing at the time. After many years, the box now resides in an attic near Athens.
ALL of my research when I was a faculty member at MIT (1979-1989) was OR-related. I had an appointment at the ocean engineering department, and I was its (only) OR faculty, being also affiliated with the MIT OR Center. My predecessor at ocean engineering (Jack Devanney) was also an OR person.
Research included a series of projects on oil spill response, a project on ocean acoustic detection, two projects on dial-a-ride systems (with Amedeo Odoni and Nigel Wilson) and a project on ship routing and scheduling (with Jim Orlin).
I also taught courses on mathematical optimization (with David Marks) and on logistical and transportation planning methods (with Amedeo Odoni, Dick Larson and Arnie Barnett), both listed jointly with other MIT departments.
My most exciting project at MIT was a project to develop graphics software for mathematical optimization courses at MIT. See HERE.
During my MIT faculty years (1979-1989), I got to know many other MIT OR faculty, including Tom Magnanti, Al Drake, Steve Graves, Rob Freund, Dimitri Bertsekas, John Tsitsiklis and Dimitri Bertsimas.
During that period I attended practically all ORSA and TIMS meetings (held twice a year), and met many OR colleagues in other universities around the world. Among them, I can name Bruce Golden, Larry Bodin, Stella Dafermos, Gilbert Laporte, Marshall Fisher, Marius Solomon, Pitu Mirchandani, Alexander Rinnooy Kan, Jan Karel Lenstra, Paolo Toth, and many others (apologies for the many omissions). Add to these the 1978 Optimization Days conference in Montreal, the 1979 International Math Programming Symposium in Montreal, the 1980, 1982 and 1983 EURO conferences in Cambridge, Lausanne and Vienna (respectively), the 1981 IFORS conference in Hamburg and the 1984 TIMS International conference in Lyngby. List may not be complete.
When I moved from MIT to NTUA in Athens in 1989, for a Professorship position on maritime economics and management in the NA&ME department, I was basically told that "you should do shipping, not OR". As a result, my OR activities scaled down significantly, even though I still kept some contact by publishing some papers and by maintaining my Associate Editorship in Transportation Science, which I actually held for 32 years (1987-2018). I served under 6 Editors-in-Chief (Amedeo Odoni, Mark Daskin, Gilbert Laporte, Hani Mahmassani, Michel Gendreau and Martin Savelsbergh). I also guest-edited two focused issues on maritime transportation and ports (in 1999 and 2015).
To be sure, there were colleagues at NTUA who were into OR more centrally than me, but they were dispersed in other (engineering) departments. These initially included Dimitris Xerokostas, George Cosmetatos and Ioannis Pappas, and later Danae Diakoulaki and George Mavrotas. There was (and still there is) no OR or management department at NTUA.
So at NTUA I was essentially doing OR whenever I could, and sometimes in my spare time. Other activities (and there were many) had priority. A sort of breakthrough came in 2010, when I published a vehicle routing paper in EJOR, for which I actually programmed the code myself (in Fortran!), some 30 years or so since I had last coded at MIT. This paper was not funded by any project. It was exhilarating to revisit the area.
I went to very few INFORMS meetings during my 24 years at NTUA (1989-2013). As far as I can recall, I only went to the 1994, 1995 and 2011 meetings, in Boston, New Orleans and Charlotte respectively. I also went to the 1990 IFORS conference in Athens, to the 1991 and 1994 TRISTAN conferences, in Montreal-Quebec and Capri, respectively, to the 2010 Italian AIRO conference in Calabria, to the 2012 EURO conference in Vilnius, to the 2012 International Math Programming Symposium in Berlin, and to the 2012 Odysseus conference in Mykonos (again, list may not be complete). There were surely other conferences too, but without a main OR content.
Needless to say, I did very little or no OR when I was CEO of the port of Piraeus (1996-2002). As I have said to many, the most serious OR problem in Piraeus was determining the marginal cost of the container terminal! This was something that we had to do in order to decide on our pricing structure. I published ZERO papers during that period, but I managed to guest-edit a focused issue in Transportation Science (1999).
At NTUA I also taught (among other courses) a course on maritime transport economics and one on applications of decision analysis in maritime transport, both of which had some OR content.
When I moved to DTU (2013-2023), I came a notch closer to OR, but I do not think it was at a level similar as MIT. Most of my research and teaching activities were in the sustainable transport and logistics area, with much emphasis on sustainable shipping. There was surely OR in both. I finished my official academic career as a Professor in the department of technology, management, and economics, division of management science, section of operations and supply chain management. People who are into OR at DTU include David Pisinger, Stefan Røpke, Jesper Larsen, Allan Larsen, Thomas Stidsen, Richard Lusby, and Dario Pacino. I even chaired a search committee for an OR Professor position.
One remarkable thing for DTU was that in my time there (10.5 years) I published more papers than in my 35 or so years at MIT and NTUA combined. Not sure how this happened, but it did. I did not do it intentionally.
In my time at DTU, I went to one INFORMS conference (2014, San Fransisco), to four EURO conferences (2013 Rome, 2015 Glasgow, 2016 Poznan, 2018 Valencia), to an INFORMS/TSL workshop (2013 Pacific Grove), to an IFORS conference (2014 Barcelona), to a Verolog conference (2014 Oslo), to an Odysseus conference (2015 Ajaccio), and to a LOGMS conference (2017 Bergen). Again, this list may not be complete and there were also other conferences without a main OR content.
I also organized, on behalf of DTU, two ROUTE workshops, one in 2014 and one in 2018, both in Snekkersten, Denmark. ROUTE workshops were initiated and organized by DTU colleague Oli Madsen, who retired in 2013. They were by invitation only and brought together many vehicle routing experts around the world.
Turns out that vehicle routing is the area in which I have most of my citations. Seven out of the top 8 most cited papers of mine (Google Scholar) are in this area. See also HERE.
Below is a pic from the 2018 workshop. One can see Irina Gribkovskaia, Maria Battarra, Gilbert Laporte, Janny Leung, Jan Ehmke, Jakob Puchinger, and many other vehicle routing luminaries.
Among my last papers at DTU was an encyclopedic paper written by a total of 82 authors. It was a paper published by the Journal of the OR Society in 2024. I wrote the section on maritime transportation. See HERE. Plus, I co-authored a paper in Transportation Science, some 41 years since my previous paper there. See HERE.
My academic career officially over, fully 8 of my top 10 cited papers, including the top 4, are OR-related (all in vehicle routing). My top cited paper is from my PhD thesis at MIT, published in Transportation Science. But most of my papers are on ship emissions. Very few of the emissions papers are OR-related.
So in what "heavy OR-content" journals have I published? Which journals qualify for that label is subjective, but still I can list the following (list may not be complete):
MIT (1979-1989): Operations Research, Management Science, Transportation Science, Transportation Research Part B, Networks, European Journal of Operational Research (EJOR).
NTUA (1989-2013): Operations Research, Annals of Operations Research, EJOR.
DTU- (2013-2023): Transportation Research Parts B and E, EJOR, Networks, Transportation Science, Journal of the OR Society.
To be sure, there were also several papers in other journals, such as in Transportation Research Parts C and D, Flexible Services and Manufacturing, and others, that had an OR content.
So all in all, and revisiting the original question, I am not sure I can answer it precisely. Perhaps an answer is, "I used to be an operations researcher. Then I hung around for a while. Then I came back but maybe not fully".
Whatever it is, I am thrilled by my (less than 24/7) engagement with OR, and super-happy to be included in Anand's OR experts list. You may form your own opinion on this question if you see that podcast (also available on Spotify).
PS
Link to ORCID
Link to career blog
