Si Qing Zheng received BS degree physics from Jilin University, China, in
1973. He worked as a research engineer at High Energy Physics Institute of
Chinese Academy in Beijing. From 1976 to 1978, he was a member of the united
development team of DJS-140 computer system. The team, which was under the
direct supervision of the Chinese government, consists of members from
Chinese Academy of Sciences, universities, and industry, and S.Q. Zheng was
one of the representatives from Academy of Sciences. This project won the
first class award at the First National Congress of Science and Technology
held in Beijing, 1980.
S.Q. Zheng went to US to pursue graduate studies in 1980. He received MS
degree in computer science from University of Texas at Dallas in 1982, and
PhD degree in electrical and computer engineering from University of
California, Santa Barbara, in 1987. After being on the faculty of Louisiana
State University for eleven years since 1987, he joined University of Texas
at Dallas as a full professor of computer science, computer engineering, and
telecommunications engineering.

Dr. Zheng has a wide range of research interests, which include algorithms,
combinatorial optimization, computer architectures, real-time systems,
networks, parallel and distributed processing, telecommunications, VLSI
design, and hardware/software codesign. He has published over 200 research
articles in these areas. In addition, Dr. Zheng was invited to participate
in industrial research and development. He made important contributions to
the development of a WDM optical router prototype and the design of an
information search engine. He was a consultant of several high-tech
companies, and he holds numerous patents. Dr. Zheng's work addresses both
theoretical
aspects and practical issues.

Dr. Zheng is also active professionally. He served as program committee
chairman of numerous international conferences, committee member of 70
international conferences, and editor of several professional journals.

Abstract of the speech:
Switching networks are widely used as core components in network switches
and routers, and communication subsyetems in parallel computing systems.
Most switching networks are multistage interconnection networks built with
small-size switching elements. Nonblocking switching networks have been
favored because of their capability of setting up any one-to-one I/O
connections. There are three types of nonblocking networks: strictly
nonblocking (SNB), wide-sense nonblocking (WSNB) and rearrangeable
nonblocking (RNB). In both SNB and WSNB networks, a connection can be
established from any idle input to any idle output without disturbing
existing connections. In SNB networks any of available conflict-free paths
for a connection can be chosen and in WSNB networks, however, a rule must be
followed to choose one. The high degree of connection capability in SNB and
WSNB networks is at a high hardware cost. RNB networks, usually constructed
with lower hardware cost, can establish a conflict-free path for the
connection from any idle input to any idle output if the rearrangement of
existing connections is allowed. Large-scale SNB and WSNB switching
networks, which are suitable for circuit switching, are usually infeasible
in practice due to their high cost. In contrast, rearrangeable networks are
more scalable because of their much lower cost. However, rearrangeable
networks are not suitable for circuit switching. Over the years, a rich
theory of nonblocking switching networks has been developed. Unfortunately,
no explicitly constructable optimal-cost SNB and WSNB network has been
discovered. Known powerful nonblocking networks are either costly and
unscalable, or very inefficient in routing connections. In this talk, we
introduce the the notion of virtual nonblockingness and almost
nonblockingness, and the concepts of virtual nonblocking (VNB) networks and
almost nonblocking (ANB) networks. We show that a VNB/ANB network functions
like a SNB/WSNB network, but it is constructed with the cost, which can be
optimal, of an RNB network. We also show that parallel/distributed routing
feature can be incorporated into VNB and ANB networks. The important
implication of the notion of VNB and ANB networks is that for large-scale
switching applications, all we need to do is to build VNB and ANB switching
networks, instead of resorting to SNB and WSNB switching networks.