Monday, November 23, 2015

Happy Thanksgiving - The 2015 Fall Edition of The Supernetwork Sentinel is Now Online

This is the time of the year when families and friends are looking forward to the very special holiday that is Thanksgiving.

There is a lot to be thankful for and especially during times when there is so much strife and suffering in the world it is important to acknowledge those who make a difference in your life.

I very much enjoyed the OpEd in Sunday's New York Times by Arthur C. Brooks: Choose to Be Grateful. It Will Make You Happier,  in which he even cites studies of the benefits of being grateful.

Besides a wonderful family, colleagues, friends around the world, a great business school and university that I teach at, I very much enjoy working with my students and collaborators through the Virtual Center for Supernetworks. Three tines a year the Center produces a newsletter, The Supernetwork Sentinel,  which highlights our activities during that period.

I am pleased to announce that the 2015 Fall Supernetwork Sentinel is now online.

I marvel at how much the Supernetwork Team at the Isenberg School of Management manages to accomplish through great collaborations and support of one another. This is the  37th edition of the newsletter. All of them can be viewed on the Supernetwork Center site.

I wish all those celebrating Thanksgiving a wonderful, restful, and delicious holiday! Thanks for your encouragement throughout the year.

Thursday, November 19, 2015

Remembering Herbert E. Scarf of Yale, Great Economist and Operations Researcher - Rest in Peace

This past Tuesday, while teaching my Transportation and Logistics class at the Isenberg School of Management, a class that I love to teach, we were discussing the importance of identifying conditions that guarantee uniqueness of equilibria. I had presented an extended model of transportation network equilibria and we were analyzing it qualitatively.

In order to emphasize to the students  the importance of uniqueness (I was focusing on link flows),  I related to the students a wonderful workshop that I had spoken at, which took place at Stanford University.  The workshop was entitled: Applied General Equilibrium Workshop and it took place March 11-12, 1988. My presentation was  (I checked on my cv): "Variational inequalities and the computation of large-scale equilibria."

I mentioned to my students how exciting it was for me to see George Dantzig there, Curtis Eaves, the Nobel laureate Kenneth Arrow, and also Herbert Scarf.  My dissertation advisor at Brown University, Stella Dafermos, was also there and we were the only two females that had been invited to take part. Strangely enough, I even recall now, although the workshop took place back in 1988,  what Kenneth Arrow was wearing (one of his favorite plaid shirts),  and Herb Scarf's shoes, which, for some reason, impressed me because they were stylish and looked so comfortable. I recall them as being beige Rockport shoes.  The audience, when I spoke about Wardrop's two principles of travel behavior, thought I had said "Wardrobe equilibrium", which Stella and I thought was very funny.

At the workshop we also discussed conditions for uniqueness, which was judged to be a very important property for policy makers when it came to equilibrium problems and a Harvard economics professor was especially avid on this point. The workshop was an intellectual delight and one of the last times that I was with my advisor at a conference since she passed away in 1990.

On Tuesday, when I was reminiscing and sharing the above in my class, I had no idea until I got back to my office and then saw the news, that Professor Herbert E. Scarf had passed away and only two days ago! 

INFORMS produced a fine tribute to Scarf  and the INFORMS President, Ed Kaplan of Yale, recently shared the sad news with all of us. I told my students today of Scarf's passing.

Scarf I remember as being very stately, pleasant, and elegant and had a very warm and welcoming way about him. I was in awe of him because of his book, "Computation of Economic Equilibria," with T. Hansen, which was published by Yale University Press in 1973. Scarf was an economist and also a great contributor to operations research.

In my first book, "Network Economics: A Variational Inequality Approach", which was published in 1993 as the first book in the series: Advances in Computational Economics, I cite Scarf's book in chapter 7, which is on Walrasian Price Equilibrium.  That book is my most highly cited publication according to Google Scholar.

Scarf was a true visionary and realized the importance of algorithmic tools to solve complex equilibrium problems. We have much to thank him for and he will be missed.

Sunday, November 15, 2015

The Paris Attacks Hit Very Close to Home

Being an academic, one is a global citizen. We have collaborators around the world, students from different countries, and we travel extensively.

When events occur even thousands of miles away that shock us, horrify us, and stun us, as happened last Friday (11/13/15) in the form of terrorist attacks in Paris, the response is to reach out and to make sure that those that we know and care about are safe.

And that is what I have been doing - emailing my collaborators and colleagues in Paris. The response from most has been quick and filled with Thank You's for thinking of us.

This afternoon I also managed to get a response from one of my undergraduate advisees who is on an exchange program in Paris. He was at the stadium last Friday that was the site of one of the terrorist attacks. He is safe and so are his friends. He also expressed gratitude for my concern.  I am shaking from relief.

Another former student with whom I have been corresponding on the refugee crisis and migration networks,  who was in my Humanitarian Logistics and Healthcare class last spring, and was on a German exchange program with UMass Amherst, wrote me today a long letter. He had been at the Eiffel Tower with a friend when the attacks started last Friday. He had started receiving alarming text messages. In his message to me he described the evening of horror and trying to make it back to his hotel with the public transport shutdown:

That meant that we had to walk home several miles, which was a very unnerving experience when you know that there is an unknown number of people with assault rifles somewhere out there. On our way to the hotel, we were the only people left on the streets, most of the bars were empty except for the waiters and a few guests gathering round the bar to watch the news on the screens. Every now and then we got passed by police cars who were rushing to the sites of the attacks, all you could hear were the sirens everywhere. It was pretty intense.

 He made it back safely to Germany today (Sunday).

One of my wonderful collaborators who hosted me, in part, when I was in Paris the last time (4 years ago) to give a keynote talk at the NetGCoop conference, and with whom I have worked on fish supply chains and network economics, wrote me a message today describing the sounds of gunfire outside his apartment.  A similar message came from another dear friend, with whom I was a Science Fellow at the Radcliffe Institute for Advanced Study at Harvard, one decade ago!

I was to have been in Paris less than two months ago for a habilitation defense (this is a degree higher than a PhD and I have blogged about this). Due to another crazy travel schedule this Fall (you don't turn down an invitation from Amazon in Seattle or invitations in Chicago, Boston, or going to the INFORMS conference in Philly), going to Europe while still covering your classes can be a challenge. Hence, I Skyped for the defense and it was a great experience.

I recently heard from one of the habilitation committee members in France, who wrote:

Thank you so much Anna for your mail and words. Personally I am safe but the situation is very surreal, extremely heavy and terribly sad. I hope things will get better with time.

He concluded his message to me with: 

May everyone be in peace.

Friday, November 13, 2015

Brilliant Lecture by Chief Technologist Dr. Eugene Litvinov of ISO New England

Today we had the honor and privilege of hosting Dr. Eugene Litvinov, who is the Chief Technologist at the Independent System Operator (ISO) New England. Dr. Litvinov spoke in our UMass Amherst INFORMS Speaker Series, which is organized by the UMass Amherst INFORMS Student Chapter. The student chapter, some faculty, and I had the pleasure of touring ISO NE's facilities in Holyoke, MA  last spring and Dr. Litvinov was so fascinating that we were thrilled when he accepted our invitation to speak.

He attracted an audience from the Isenberg School of Management, the College of Engineering, and even folks from Physical Plant at UMass since we operate our own microgrid as well as other guests from the community. It was great to see so many PhD students and even MBA students in attendance on a Friday afternoon.

The title of his talk was "Challenges of the New Grid."

ISO NE ensures that the lights stay on in our region, that is, this organization ensures electric power reliability. It is also involved in wholesale trading as well as planning for electric power.

We began his visit with a delicious lunch at the University Club at UMass and were joined by Professor Erin Baker and two of her doctoral students. She is the PI on an NSF IGERT on wind energy. Also joining us was one of our PhD students from the Isenberg School.

The conversation at lunch was so interesting. We discussed issues of survivability, cybersecurity and the grid, renewable energy, internships, skillsets needed in this industry, and other topics and we made it to the seminar location jut in time.

The audience was eagerly awaiting Dr. Litvinov'a presentation.

I started the introductions and then our new Student Chapter President, Zana Cranmer, completed the welcome. We also noted that the student chapter last week at our INFORMS conference in Philadelphia had received the summa cum laude award from INFORMS. We had chocolate cake (to be eaten after the talk) and our award plaque displayed.
Dr. Litvinov mentioned how the grid consists of the eastern interconnection, the western interconnetcion, and that Texas is its own country.

He noted that ISO NE manages $11 billion in energy capacity a year, which is mind-boggling. Every second the monitoring of supply and demand of electricity takes place since electric power cannot be stored.

New challenges for our region include that a big percentage of the fuel is now natural gas and we don't have sufficient pipeline capacity to transport it (our region does not produce natural gas). This winter could be interesting, to say the least.

He noted that we now need different ways of controlling the system since it is much more decentralized than it has ever been. He spoke of offering customers different levels of reliabilty, which I found quite interesting.

He also noted that the transmission architecture is a mesh and the distribution architecture of the grid is radial. He emphasized the need for greater flexibility. I very much appreciated his emphasis on the importance of definitions whether they are for flexibility, reliability, survivability,  or even resilience. He spoke about risk-based optimization, which I thought was very cool, and noted robust optimization several times in his talk. I might add that Litvinov has collaborated with Dimitri Bertsimas of MIT Bertsimas spoke in our series a few years ago, as did his wife, Georgia Perakis, who had the same advisor at Brown University as I did (Stella Dafermos).  so I guess Bertsimas is my academic brother-in-law.

Dr. Litvinov  emphasized the importance of keeping the system in balance and to manage the uncertainty. I liked him saying that one needs to determine the largest set of uncertainty that can be handled without violating constraints and said that he has a paper on this, which I definitely want to read.

Dr. Litvinov also discussed that we are moving from coordinated control of the grid to cooperative control (hopefully) along with decentralized decision-making. He had visited Paris recently and viewed how electric power is managed there.
He  presented quite a few mathematical optimization models so it was great for the students to see how important mathematical programming and optimization are in this critical infrastructure sector.

His lecture was brilliant and so impressive.

The questions that followed demonstrated the interest of those who attended. There were questions on renewable energy, what his vision for the grid would be for 2030, and even cybersecurity (a growing group at ISO NE).

Dr. Litvinov stayed to answer more questions and was very generous with his time and, given his reponsibilities, we are truly grateful for his visit and his talk.
And then it was time to indulge in a piece of delicious cake from Whole Foods. What a great Friday afternoon and what a terrific day, which started with meetings in Computer Science this morning.

Monday, November 9, 2015

What is Your Erdos Number and Network Science

On Friday, October 30, UMass Amherst had the pleasure of hearing Professor Albert-László Barabasi of Northeastern University speak on Network Science: From Structure to Control

This was a talk not to be missed. The talk was co-hosted by several entities at UMass including the Computational Social Science Institute (CSSI) ( a great group of colleagues with whom I enjoy being affiliated with). Room 150 in the Computer Science building was packed for his talk with an audience from many schools and colleges on our beautiful campus. My doctoral student, Shivani Shukla, and I represented the Isenberg School. Professor David Jensen of Computer Science introduced our distinguished speaker.

We had hosted Barabasi at the Isenberg School back in 2006 when I was on sabbatical at the Radcliffe Institute at Harvard in our great UMass Amherst INFORMS Speaker Series (and what an amazing list of speakers we had that Spring 2006, which even included Braess of Braess paradox fame).

I had last seen  Albert-László at a Network Science conference at the Media Lab at MIT, a few years ago,  to which I brought my doctoral student (now a Professor), Min Yu.

Barabasi began his lecture (I would have blogged it sooner but last week I was blogging from the INFORMS conference in Philadelphia and I was swamped) by bringing up Paul Erdos, a fellow Hungarian. Erdos,  the renowned mathematician,  had over 500 collaborators (some say 509 and others 511 - I have not counted them).  Erdos traveled the world from collaborator to collaborator with a suitcase typically staying for about 5 days.

Identifying one's Erdos number has become quite the hobby among STEM (and some other) folks. One has an Erdos number of 1 if one was a direct collaborator of Erdos', a number of 2, if one co-authored with a co-author of Erdos', and so on. My Erdos number is 4, by way of Paul Dupuis, Ofer Zeitouni, and Persi Diaconis.

You may be more familiar with the  Bacon number (named after the actor Kevin Bacon who starred in the move, "Footloose." 

And, of course, some actually know their Erdos + Bacon number.  Barabasi mentioned that his Bacon number was actually lower than his Erdos number, since he had been in a movie with someone who was in a movie with so and so and so on who starred with Kevin Bacon.

Now, what does this all have to do with Network Science?

Erdos is known for the Erdos-Renyi model in graph theory, which describes random graphs or networks. The degree distribution of the World Wide Web is not Poisson but follows the power law. Essentially, there are a very large number of small connected nodes in such a network and a few that are very highly connected. The World Wide Web is like an airline network with hubs. The Internet is a scale-free network according to the famous paper by yes, Faloutsos, Faloutsos and Faloutsos, but there has been some discussion about this claim.

Barabasi emphasized in his talk that a few actors are "hubs" and metabolic and protein interaction networks, which have evolved over 4 billions of years, also have hubs.

He noted that in network science (his books are definitely worth reading and he is highly cited), it is not just a matter of connecting nodes but that nodes are also evolving dynamically. He spoke of the preferential attachment model and then asked the question of where robustness comes from. He spoke about the Internet being robust to random failures and also noted that hubs are important both in the spread of ideas and diseases, as well. He referred to Vespignani, whom I have had the pleasure of meeting through the I3P association, which is a consortium based at Dartmouth.

His recent research, has, among many fascinating topics, been focusing on control. Just think of a car with 6,000 components but essentially only 4 are needed to control it. He also mentioned Kalman of Kalman filtering fame.

He described an interesting study that he conducted in Hungary in an organization to identify who were the hubs and found the 2 or 3 most influential people, one being the custodian, who was like "gossip central."

His talk was delivered with his fantastic energy, dynamism, and sense of humor. He included videos in addition to many vivid photographs. If you did not love networks before his talk, you would have fallen in love with them during it.

I was also very lucky to be invited to join Barabasi and a few colleagues from economics, computer science, and sociology (Professor James Kitts, who is the Co-Director of CSSI with Professor David Jensen). I also brought my husband along since he, like Barabasi, has a PhD in physics.

The discussions at dinner were fabulous. I wish that the evening would not end. We talked about topics as wide ranging as identifying Nobel prize winners from co-authorship of papers; determining through the language in an abstract whether a scientific paper was written by a female or a male, and we even discussed the Braess paradox.  I keep on emphasizing the importance of including flows and economic behavior of decision-makers in network science. We also discussed the success of the first PhD program in Network Science, which he helped to establish at Northeastern University and a similar PhD at a university in Hungary that he is affiliated with and that the billionaire Soros is helping to fund. Yes, Soros is also Hungarian.

below are photos taken at the dinner that great Friday evening.
Thanks to Professor Barabasi for coming out to Amherst from Boston and for your brilliant lecture on Network Science!

Thursday, November 5, 2015

Supernetwork Center Associates Prominent at INFORMS Conference in Philadelphia

We have returned from the great INFORMS conference, which took place in Philadelphia, November 1-4, 2015.

This conference also served as a venue at which many of the Center Associates of the Virtual Center for Supernetworks at the Isenberg School of Management got together and presented their latest research plus had a great chance to reconnect face to face and to socialize as well. In fact, there were 11 Center Associates present, including the Center Director (yours truly).

Professor Dmytro Matsypura of the University of Sydney in Australia got the prize for the greatest number of miles traveled!  And Center Associate Professor Patrick Qiang, from Penn State Malvern, traveled the least and got to sleep in his own bed.

Some of the highlights included: the first presentation by Dr. Michelle Li as an Assistant Professor at an INFORMS conference, my doctoral student, Shivani Shukla presenting for the first time at an INFORMS conference, and she presented on our work in a session on cybersecurity organized by Professor Laura McLay of the University of Wisconsin, Professor Min Yu of the University of Portland presenting in a session organized by Professor Vladimir Boginski of the University of Florida on our work on fashion supply chains and ecolabeling,  and a terrific session organized by Professor Jose Cruz of the University of Connecticut on corporate social responsibility, which included presentations by Center Associates Professor Zugang Liu of Penn State and Professor Trisha Anderson of Texas Wesleyan University, and also a presentation by Professor Cruz! In addition, Center Associate Professor Amir H. Masoumi of Manhattan College had a poster presentation and joined us for several social activities. My doctoral student, Sara Saberi, also had a scheduled paper presentation and was present for most of the conference but then received a request for an on-campus interview so her presentation was given by Shivani Shukla.  Sara also took part in the INFORMS doctoral colloquium and received the WORMS (Women in Operations Research and the Management Sciences) travel award grant - so, congratulations!

Several of our presentations have now been posted on the Supernetwork Center website.

It also helps to have collaborators since two of my talks were scheduled in parallel sessions and, so far, I can only be in one location at a time.

Below are some photos taken of our group.

Another highlight of the conference was to have our Networks Against Time: Supply Chain Analytics for Perishable Products book, displayed at the Springer booth in the Exhibition Hall.
We also enjoyed a delicious dinner in Philadelphia's Chinatown as well as taking part in the WORMS Awards luncheon.
Another wonderful event was the INFORMS Student Chapter Award ceremony at which the UMass Amherst INFORMS Student Chapter received the top award, the summa cum laude award, from INFORMS.  Several Center Associates (Shivani Shukla and Sara Saberi, both of whom have served as officers and Shivani as President), took to the stage. Professors Yu, Li, and Masoumi came to cheer them on, along with other present and previous chapter officers and members. And the desserts at the reception afterwards were fabulous!

It takes a great team to accomplish a lot, and the Supernetwork Center Team at the Isenberg School of Management, with members from 3 different continents is a terrific group.  Having  collaborators is key to success in research and that is certainly what we try to do and we have a very enjoyable time doing it.

Wednesday, November 4, 2015

UMass Amherst INFORMS Student Chapter Shines at Award Ceremony at Annual Meeting in Philadelphia

I am back from the great INFORMS conference, which took place in Philadelphia, November 1-4, 2015.  It was an exceptional conference and one of the many highlights was the Student Chapter Award ceremony that took place this past Monday evening.

As readers of this blog know, our UMass Amherst INFORMS Student Chapter received the summa cum laude award for its activities and it was wonderful to see other chapters recognized with both the magna cum laude and cum laude awards. More information on the selection process is here.

The UMass Amherst INFORMS Student Chapter is now in its 12th year of operation and I have enjoyed serving as its Faculty Advisor during this period. The members (graduate students as well as some faculty) and officers hail primarily from the Isenberg School of Management (ISOM) (principally from the Department of Operations Management) and from the College of Engineering (mainly from the Department of Mechanical and Industrial Engineering (MIE)).

Needless to say, the students (and I) were so excited about the evening ceremony. The news had spread and quite a few of our alums, who are now professors at various colleges and universities,  also stopped by to help us celebrate.

Below are some photos that I took of the event.
Last year's UMass Amherst INFORMS Student Chapter President, Michael Prokle, received the Judith B. Liebman Award from INFORMS for his exceptional service to the chapter. I had nominated Michael for this award because he had worked tirelessly for the chapter and we had many terrific events, including our 10th anniversary celebration. Michael was given the award plaque by incoming INFORMS President, Professor Ed Kaplan of Yale University, and Dave Hunt, the VP of Chapters / Fora.

Michael is the 4th recipient of the Judith Liebman Award from the UMass Amherst INFORMS Student Chapter with the others being: Dr. Tina Wakolbinger, Dr. Patrick Qiang, and Dr. Amir H. Masoumi. The latter three were my PhD students in Management Science at the Isenberg School of Management, and they are now are very successful professors.

It was very exciting to see our student chapter receive the top award and to see the Chapter Officers (several present and past ones)  on the stage.
Joining David Hunt and Ed Kaplan on the stage were: this year's Chapter President, Zana Cranmer of MIE, Tulay Varol of ISOM (a former chapter officer), Michael Prokle, Pritha Dutta of ISOM, Shivani Shukla of ISOM and past President, Sara Saberi of ISOM, who has held many offices in the chapter, Heng Chen, also of ISOM and a past officer, and Amirhossein Alamdar Yazdi of ISOM and past chapter officer.

After the awards were given out, we posed with some of our alums and with Professor Hari Balasubramanian of MIE, and then it was time to go to the reception next door with sumptious food and fabulous desserts.
Joining me in the above photo are Isenberg School of Management PhD alums, who came to support our students, and they were all very active members of our student chapter: Dr. Ameera Ibrahim of St. Mary's College in CA, Dr. Farbod Farhadi of Roger Williams University in Rhode Island (they were both Professor Ahmed Ghoniem's doctoral students), and my former PhD students: Dr. Min Yu of the University of Portland in Oregon, Dr. Michelle Li of Arkansas State University, and Dr. Amir H. Masoumi of Manhattan College in NYC.

After a very special night, some of us got together the next morning for the Chapter and Fora breakfast. I always emphasize the importance of showing up to students!
Many thanks also to Courtney Biefeld of INFORMS and to the official photographer for all that they do to help us with making activities with our students a success! Also, many thanks to the administrators at the Isenberg School of Management and the College of Engineering for their support of the chapter.
Congratulations to everyone and keep up the terrific work!