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Wah receives Tsutomu Kanai Award

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By Tom Moone, ECE ILLINOIS
May 18, 2009

  • Prof. Benjamin Wah received the 2009 Tsutomu Kanai Award from IEEE.
  • Wah was recognized for "outstanding contributions to the theory and applications of distributed multimedia and nonlinear optimization algorithms."
  • Wah's research has promising applications for videoconferencing technologies.

Benjamin W. Wah
Benjamin W. Wah

ECE Professor Benjamin W. Wah, an expert in multimedia signal processing, had felt for a long time that the quality measurements used in evaluating voice over IP (VoIP) were not looking at the right parameters. “One of the problems that people are facing today in terms of multimedia, such as video conferencing and voice over IP, is that they measure quality quantitatively by numbers,” said Wah. This measurement looked only at the objective measures of data transferred over the Internet, not the subjective experience of users of interactive multimedia technology.

Wah, who is the Franklin W. Woeltge Professor of Electrical and Computer Engineering and a research professor in the
Coordinated Science Laboratory, wanted to examine a different avenue for determining the quality of VoIP. “What we have looked at is how to systematically measure perceptive quality of voice over IP or interactive multimedia and to translate the measurements into control strategies at run time,” he said.

The work that Wah has led in this area of research has earned him the 2009 Tsutomu Kanai Award from the IEEE Computer Society “for outstanding contributions to the theory and applications of distributed multimedia and nonlinear optimization algorithms.”

In their work, Wah and his students Batu Sat and Zixia Huang recorded sample conversations that were then artificially adjusted to simulate a variety of network conditions, such as lossy or jittery conversations over delayed Internet connections. Subjects then listened to these conversations and evaluated the subjective experience they felt while listening.

For example, Wah explained that injecting delays into online transmissions can improve accuracy, but it decreases the sense of interactivity. “You actually perceive that the other party is responding slowly to the conversation,” said Wah. “Although it does not give you a real-time perception of the conversation, it may sound clearer and more intelligible.” The goal Wah and his students undertook was to determine the best balance between delays and subjective feelings of interactivity.

Wah and his students were then able to take this qualitative data and develop an algorithm for learning the mapping between delays and interactions under diverse network conditions. Overall, they spent more than two years collecting and evaluating this qualitative data to come up with their algorithm.

“There had been little work done in this area in the last 10 to 15 years,” said Wah. “Subjective tests are not ‘sexy’ research topics.” Wah and his students have developed a formal mathematical foundation from which other researchers can perform a small number of tests in order to have confidence in the results. Rather than performing an infinite number of tests of every possible network condition, “we have found that in order to arrive at 95% confidence on the operating point with the best perceptual quality under a network connection, we can perform five to six tests of different operating points under this connection in order to identify the best point and the corresponding operating conditions,” said Wah.

 The next phase for this research will be to extend it into the area of videoconferencing. “We are working with researchers in Singapore to further develop this system for telepresence,” he said.

The Tsutomu Kanai Award was established in 1997 by an endowment from Hitachi Ltd. Tsutomu Kanai served as president of Hitachi for 30 years. The award is given each year to someone who has made exceptional contributions in the area of distributed computing systems and its applications. The award includes a certificate, crystal memento, and $10,000 honorarium.

Wah has been at Illinois since 1985. In addition to this award, he is a recipient of the IEEE Computer Society W. Wallace-McDowall Award, the Pan Wen Yuan Foundation Outstanding Research Award, the Raymond T. Yeh Lifetime Achievement Award, the Richard E. Merwin Distinguished Service Award from the IEEE Computer Society, and the IEEE Third Millennium Medal. He is a Fellow of IEEE, the American Association for the Advancement of Science, and the Association for Computing Machinery.

Editor's note: media inquiries should be directed to Brad Petersen, Director of Communications, at bradp@illinois.edu or (217) 244-6376.

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