Professor Alexander Vardy
Electrical engineering Professor Alexander Vardy, a renowned researcher in information and coding theory, has been appointed as the first Jack Keil Wolf Endowed Chair in Electrical Engineering at the University of California, San Diego. The endowed chair was established in memory of Jack Keil Wolf, a longtime professor at the UC San Diego Jacobs School of Engineering and a pioneer in information theory and its applications. Wolf died on May 12, 2011, at the age of 76. (Read the New York Times obituary.)
The chair has been endowed with funds raised in honor and memory of Wolf’s lifetime of professional achievements in research and teaching. More than 50 people, including colleagues, former students, friends and family contributed to the fund. Vardy said the scope of the contributors is a tribute to Wolf’s impact in the lives of so many.
“Being appointed to the Jack Keil Wolf Chair is such a tremendous honor. Jack Wolf was a shining light,” said Vardy. “For me, personally, he was a role model throughout my career; I know that this is a feeling I share with many people. It is with the greatest gratitude and humility that I would like to thank the donors to the Wolf Chair, large and small. Indeed, Jack was like a bright torch that lit the paths of countless people. I am extremely honored to have the opportunity of carrying forward a bit of that flame.”
That flame, at least on the research side of Wolf’s legacy, is important in the fields of information theory and coding theory. Information theory is a branch of applied mathematics and electrical engineering concerned with transmitting data from point A to point B without error. Whether that data is images taken by a spacecraft on Mars or photos taken on your smartphone, it is converted into a sequence of ones and zeros and bundled into packets to transmit down the line. Claude E. Shannon, who developed the field of information theory in the 1940s and 50s, posited that it was possible to achieve what he called “channel capacity”—that is, perfect data transmission which is both reliable and efficient. This Holy Grail of capacity—that you could transmit data without error while sacrificing the bare minimum in storage space or transmission time—has driven the research of coding theorists, including Wolf and Vardy, for decades.
Jack Keil Wolf
Beyond research, Wolf was known for his generous hospitality, his sense of humor and his excellence in teaching. Paul Siegel, a professor of electrical and computer engineering at the Jacobs School and former director of the Center for Magnetic Recording Research, said Vardy is the ideal candidate to serve as the first Jack Keil Wolf chair.
“He is one of the most original, creative, and productive researchers in coding theory in the past couple of decades,” Siegel said of Vardy. “He’s made numerous seminal contributions. He has a number of codes and algorithms that are referred to by his name. He’s a perfect choice if you want to recognize someone who is a research star. Like Jack, Alex also cares a lot about teaching, and the students in Alex’s undergraduate and graduate classes consistently rank him very highly.”
Vardy is a renowned expert in coding theory. His research has led to a better understanding of the uses and limitations of error-correcting codes in encoding data for transmission and storage. His work has widespread implications for a plethora of devices, from satellites to cell phones and from computer drives to CDs.
“Alex is not only a world renowned researcher in information theory with numerous recognitions and awards, but also an outstanding teacher on both graduate and undergraduate levels. In that sense he is somewhat stepping into Jack’s shoes, as Jack cared a lot about students and their education,” said Yeshaiahu (Shaya) Fainman, professor and chair, Department of Electrical and Computer Engineering. “We are very fortunate to have Alex on the ECE faculty at UC San Diego and this recognition is a clear manifestation of our appreciation to his continuing contributions. Now that our ECE department is extending its research into the exciting field of engineering medical devices and systems, I feel Professor Vardy will be instrumental in establishing and making successful this new application field.”
Reaching for Shannon’s ‘Capacity’
Over several decades, coding theorists have developed error-correcting codes that build redundancy into the data being transmitted to increase the probability that it will be understood perfectly at its destination. Vardy says people do this naturally in speech, repeating the same message several times to make sure they are understood correctly.
In error-correcting codes, the idea is to add additional bits of data in a pattern that can be used to reconstruct the original message if it gets corrupted during storage or transmission. Among the most widely used error-correcting codes are the Reed-Solomon codes. Despite the popularity of these codes in many applications over several decades, the algebraic decoding algorithms that were used to recover the stored or transmitted data could not fully exploit the probabilistic nature of the corrupting channel noise. But Vardy and his research collaborator Ralf Koetter discovered a clever way to marry probability and algebra in a new decoding algorithm that vastly improves the error-correcting performance of Reed-Solomon codes. Their paper on what is now called the Koetter-Vardy algorithm received the IEEE Information Theory Society’s best paper award in 2004.
More recently, Vardy’s research has focused on bridging the gap between theory and practice for polar codes. Invented in 2009 by a coding theorist named Erdal Arikan, polar codes are considered the next major breakthrough in coding theory, marking a completely new approach to error-correcting codes. Working with one of his postdoctoral researchers, Ido Tal, who is now a professor at Technion – Israel Institute of Technology, Vardy developed an efficient linear-time algorithm for constructing polar codes that has become the de facto standard used by everyone in the field.
Vardy came to the Jacobs School in 1998 from the faculty of the University of Illinois, Urbana-Champaign. Among other honors, he is a Fellow of the IEEE and a past Editor-in-Chief of the IEEE Transactions on Information Theory. He received his Ph.D. in Electrical Engineering in 1991 from Tel Aviv University. Vardy is a recipient of a David and Lucile Packard Fellowship and a National Science Foundation CAREER award.
Setting a High Standard for Teaching
Perhaps the best testimonial in support of Vardy’s appointment to the Jack Keil Wolf chair comes from a student who studied under both men. Eitan Yaakobi was a graduate student at Technion when he first experienced Vardy as a teacher. Vardy was then on sabbatical from UC San Diego and teaching at Technion. Yaakobi wanted to do his graduate work in the United States and knew that the faculty at UC San Diego was widely recognized for its achievements in information theory.
In addition to taking graduate classes with Vardy and Wolf, Yaakobi was jointly advised by Wolf, Vardy and Siegel as a Ph.D. student. He is now a postdoctoral researcher at Caltech and still affiliated with the Center for Magnetic Recording Research at UC San Diego. Yaakobi recently accepted a faculty position at Technion beginning this winter quarter.
He believes he learned as much from his Ph.D. advisors about teaching as he did about information theory, mostly about the importance of preparation, and being exceptionally well organized in practice and in thought.
“One thing you can say about Alex Vardy is that ‘perfectionist’ is not enough to describe him,” said Yaakobi. “I think his and Jack’s standard for teaching was the same as, and maybe higher, as it was for research. They have this amazing skill and ability to take complex ideas and explain them so that anyone can understand them. They can also take simple ideas and complicate them for a tough final exam.”
Wolf’s Legacy Lives On
As a Ph.D. candidate working with Wolf, Vardy and Siegel, Yaakobi had the unique experience of becoming their research partner and a co-inventor on some important work in coding for flash memories. Calling it a “fun mathematical problem,” Vardy said the team’s work significantly increases the number of times you can write over data stored in flash memory devices. This is important because, in contrast to magnetic disk drives that can be erased and over-written an unlimited number of times, flash memories can tolerate only a limited number of such erase operations before failing.
Wolf, who joined the faculty of UC San Diego as a professor of electrical and computer engineering in 1984, made an early mark in the field of information theory, devising a startling theorem with David Slepian proving that two separate streams of correlated data can be sent independently with the same efficiency as if there were only one sender who knew both streams. Researchers would later use the Slepian-Wolf theorem, one of the most important early results in network information theory, to develop high-speed computer networks. The incredible data storage capacity offered by today’s hard disk drive and tape drive technology also owes much to Wolf. His contributions earned him the prestigious 2011 Marconi Society Fellowship and Prize, known as the Nobel Prize for engineering, an award he shared with Qualcomm co-founder Irwin Mark Jacobs. Wolf was a member of both the National Academy of Engineering and the National Academy of Sciences. In 2001, he received the Claude E. Shannon Award, the highest honor bestowed by the IEEE Information Theory Society.
Now, in the research of Vardy, Siegel, Yaakobi, and many others, Wolf’s legacy lives on. The IEEE Information Theory Society recently decided to rename its annual International Symposium on Information Theory Student Paper Award in honor of Jack Wolf. At the UC San Diego Jacobs School of Engineering, an additional fund has been established in the Department of Electrical and Computer Engineering in his name. Known as the Jack Keil Wolf Endowed Fund in Electrical and Computer Engineering, it will support undergraduate and graduate students, postdoctoral fellows and faculty exchanges across all ECE groups and disciplines.
“The importance of his contributions hasn’t diminished with time; in fact, his work has grown in significance,” said Siegel, a longtime colleague of Wolf’s, who led the effort to establish the memorial fund. Wolf held an endowed chair at the Center for Magnetic Recording Research, where he led the Signal Processing Group, dubbed the “Wolf Pack.”
“Jack’s legacy to UC San Diego, electrical engineering, information theory and magnetic recording lives on through the many students he taught, mentored and launched into successful careers in academia and industry,” said Andrew Viterbi whose generous challenge gift to the endowed chair fund inspired so many others to contribute. Viterbi is a professor emeritus in the Department of Electrical and Computer Engineering. “Jack Wolf was my closest colleague and best friend over many decades. I miss him deeply,” Viterbi said.