Tuesday, January 24, 2012

In Memory of Sheng Yu (1950-2012)

(photo courtesy Manfred Kudlek)

Yesterday I heard the sad news that Sheng Yu, a Chinese-Canadian computer scientist, and a good friend and colleague, died this weekend in London, Ontario.

I first met Sheng Yu shortly after I arrived in Waterloo as an associate professor in 1990, but I can't remember the circumstances. At the time he was working actively with the late Derick Wood (for whom Sheng gave a memorial talk just last year), who taught at Waterloo at the time, so it probably was through Derick.

We wrote a paper together on regular languages with polynomial densities. Later, Sheng asked me an interesting problem about whether it is possible to find a sparse language L such that L2 = Σ*. I found one example, and Andrew Granville found another. In 1994, we all wrote a paper with Per Enflo, who had found yet another example. Our last joint paper was in 2001, joint with Mike Domaratzki, on covers of formal languages. Although we did not work actively together in the last ten years, we often spoke on the phone.

Sheng got his master's degree in computer science from Waterloo in 1982, under John Beatty, and his Ph. D. in 1986 under Karel Culik II. Then he taught for several years at Kent State before taking a position at the University of Western Ontario.

Sheng's work on state complexity is well-known in our community. His influential 1994 paper with Zhuang and Salomaa is his most-cited non-survey paper (with Google scholar giving 156 citations), and re-introduced state complexity as a research topic to the theoretical computer science community. (It turns out that many of the results in that paper were already discovered by the Soviet computer scientist Maslov in 1970, but Maslov's results were either not known or quickly forgotten in the West.) Since then, state complexity became an active area of research, with dozens of papers published.

When I first met Sheng, I thought his only interests were about automata. I quickly found out I was wrong. He was incredibly broad, publishing papers on object-oriented programming, parallel processing, parallel programming, and teaching a wide variety of courses at UWO, including computer architecture, programming languages, and of course, automata theory.

Sheng Yu also had influence in other ways. He was one of the people responsible for the CIAA conference series, and served on the program committee of dozens of conferences. He also was one of the people responsible for the Grail system, which is widely used to carry out experiments with automata. He supervised dozens of graduate students.

Sheng told me a little bit about his life in China. He got his Ph. D. older than many of his contemporaries because his life was disrupted by the Cultural Revolution. He still had family in China, which he kept in close contact with.

About 5 years ago In 2000, Sheng had a heart attack while playing tennis at UWO. Luckily, he was very near the university hospital, and immediately went there, and the good care he received saved his life. He told me that his family had a history of heart disease and that he had high cholesterol, which he tried to control through diet.

I will miss him as a colleague and friend.


Unknown said...

We will miss him.

Anonymous said...

That is very sad. A bright mind has been lost. :( - Thomas Z

Anonymous said...

Thanks for this tribute to Dr. Yu. I am a PhD student in the Department of Computer Science at UWO, and this was quite shocking to hear about. He will be missed.

Anonymous said...

Sad news indeed. My condolences to his family. He will be missed.

Lin said...

RIP Professor...

demo said...

You will be missed, Dr. Yu

A. Fellah said...

I was Dr. Yu's first PhD-student at Kent State University (USA) and finished my work with him while he was at UWO.
Dr. Yu was the one who introduced me to theoretical computer science, in particular automata and formal languages, an area of research that I particularly still enjoy.

I visited Dr. Yu several times at UWO and kept in touch with him through the years. Our last contact was just few weeks ago. In fact, I just e-mailed Dr. Yu last night, Tuesday 24, because he didn't reply to my e-mail sent on Monday, one day before he passed away.

He will be definitely missed but he will never be forgotten. My heartfelt condolences to the family.

A. Fellah

Andrei Paun said...

Thanks Jeff for the nice comments about Sheng. Just a quick note: his heart surgery was in 2000 ... I was his PhD student at that time.

It is a great loss for the community and a personal loss for me.

Andrei Paun
Louisiana Tech University

Mahdi said...

I was shocked when I listened the bad news. I took a course under him which was great. The thing attracted me most is his knowledge and interest about different people and their culture. I work in late night like him, so we meet in the corridor many times at night time when the UWO looks silent and have chat about many things, even last week or two I have chat with him regarding our future plan etc. I think I last hear his footsteps in our corridor just several nights back it was around midnight and thought to open the door and a have chat but was little bit lazy and thought maybe next time, who guess that would be the last chance.RIP for Sheng.

Wenyan said...

I'm one of students in Dr. Yu's "Formal Language II" class. He will be missed forever by students like me.

Wenyan Qin
IBM Canada

Andrei Paun said...

For those who want to attend:

The Funeral is scheduled for February 3, 2:00pm-4:00pm at James A Harris Funeral Home (220 St. James Street, London, Ontario N6A 1W9).

Yongbo An said...

Shocking and sad!!! My wife and I will miss him...

编程心得 said...

It is really a sad news. RIP Dr. Yu.

-Hailing Zhang

Zheng (John) Ye said...

It is a shocking news when my friend called me about it. I feel so sad, sad, and sad.

I was one of Sheng's students. I still remember Sheng and his wife with my family together for Chinese new year party at my home. I still remember we all teachers and students had BBQ party at Spring Bank Park. I still remember we celebrated the 60th birthday for Sheng. I still remember a lot of things with Sheng, My boss, my teacher, my friend.

Oh, it is so bad, so bad, so bad. My family and I will miss you.

Good Sleep, Sheng !

Your student, Zheng Ye

Anonymous said...

I was so shocked on the news that Dr. Yu passed on the Chinese New Year's eve.

I was a PhD student at UWO and took one course on Object Oriented Languages offered by him. We played tennis once a week in Year 2003 and 2004. It was in June 2011 when I flied from Beijing to Ottawa for a conference, I detoured to UWO and got a chance to visit him. But who could guess that would be the last meet?

My condolences to his wife and other family members. Sheng Yu will be remembered, both as an outstanding computer scientist and a good tennis player.

Juntao Ye
(Institute of Automation,
Chinese Academy of Sciences)

Anonymous said...

Professor Yu taught me two courses. We became friends soon after when I realized that we shared common interests such as politics, religion and sports. I enjoyed debating with him and picking his brain. It was very interesting and enlightening to see someone who spent most of his academic career dealing with automata and theoretical comp sci. transfer these skills to the social sciences world. We even had a long term plan about writing a paper together surveying authoritarian regimes and examining their successes in certain aspects where we thought democratic regimes had failed. He wasn't an advocate of authoritarianism of course but that's how someone who's versed in logic thinks. He's interested in mining the good things out of the bad no matter how. We also played ping pong together and he taught me how to return the insane topspin that he used to throw at me. It's very sad. I used to look forward to visiting him in his book-filled brightly-lit office. He will certainly be missed. My thoughts and condolences go out to his family and friends.

Qingping Feng said...

I am saddened by the news. I have known Sheng for many years. He is an accomplished researcher, teacher, and a well-respected friend. It's hard to believe that he just suddenly left us at the peak of his career. He will be missed.

Ying, Bo, Baozhen said...

We are saddened by the passing of Dr. Sheng Yu. He was a great but humble man who loved his family, relatives, and students. Our family will always remember the kindness he shown us, and we wish him the best in heaven. RIP Sheng Yu.

Anonymous said...

Sad news... RIP Professor Yu.

Anonymous said...

I was just back from my trip to China and so sorry to hear the loss. Very sad! Sheng had been my supervisor for years and enriched my knowledge of inspiring subjects within the field of Object Oriented languages. He is a great mentor and friend. We played tennis in campus in summer seasons and it was the best of times. My deepest condolences to his family and his friends. You will be missed!


Haitong said...

I was just back from my trip to China and so sorry to hear the loss. Very sad! Sheng had been my supervisor for years and enriched my knowledge of inspiring subjects within the field of Object Oriented languages. He is a great mentor and friend. We played tennis in campus in summer seasons and it was the best of times. My deepest condolences to his family and his friends. You will be missed!

Anonymous said...

Finally posted on the funeral home web page http://www.harrisfuneralhome.ca/index.php

The funeral service will be conducted at the James A. harris Funeral Home, 220 St. James St. at Richmond St., London, Ontario on Friday, February 3 at 11:00 am, with visitatio nprior from 10-11 am.

jerassi said...

RIP Professor.

Anonymous said...

This is so sad news. I took one of his courses and he was always nice to everyone. RIP professor, you will be missed. --- Liyun

Anonymous said...

This is so sad news. He will be missed. I think we need do something for his family.Let he know, we are all together.

Anonymous said...

He will be missed by his students in course CS3342b (2012) The University of Western Ontario

Anonymous said...

RIP Professor Yu. I remember when I was taking your course. You will be truly missed. - SS

Peter Goodman said...

I will miss Sheng. We worked together for three years during my undergraduate degree. Over that time, he was my professor for two courses.

I have fond memories of sitting in Sheng's office, admiring his books and his piles of papers, and talking about his past students and what they were up to.

Sheng was very generous with me. I remember popping into his office at the end of my second or third year of university and nervously asking him if he wanted an undergraduate research assistant. I had no idea what to expect. By that time, it was too late to apply for any grants, but Sheng decided that he would employ me on a part time basis out of pocket! That was a fun summer, an interesting project, and where our friendship began.

The next summer, we got a small NSERC award and worked on maintaining Grail+. Again, Sheng was very generous and always supportive.

In my final year, Sheng supervised my thesis project and together we re-implemented Grail+.

I will always remember him. Goodbye, Prof. Sheng Yu.

Anonymous said...

I am shocked to hear the passing away of Sheng Yu.

I first met Sheng when I was a graduate student at Waterloo. In some sense, we were office mates. I was sharing a big office in the fifth floor of the math and computer building, and Sheng's office was slightly tucked inside that office. We both were among the few who used to work late in the night. We used to go for coffee/tea in the night to the campus center, and that's when we started playing table tennis there. It was usually less crowded at those times. I had never touched a table tennis racket before I met him, but recently I have won some small local tournaments here, and all the credit go to Sheng for his coaching -- by just playing with me patiently for several days and months.

He used to be passionate about music and photography. He had a sophisticated Nikon camera at that time, and I have pictures of us surrounded by snow during the Waterloo winter days.

I helped him move his stuff to Kent, and I had kept in touch even after I moved back to India. During my several visits to Waterloo afterwords, I have never missed to meet him. Either he would come down to Waterloo to meet me or I would visit him in London. We have discussed quite a bit about cultural revolution in China and Indian democracy.

His generosity and gentleness have been mentioned here, and I echo the sentiments. I will miss him during my visits to Waterloo.
-- Venkatesh Raman