F or the past 50 years, we have based most (if not all) of the world’s comput- ers on the von Neumann model, which Alan Turing’s theoretical model in turn inspired in the first half of the 20th century. 1,2 Although we see the von Neumann model’s influence on some of today’s high-performance computers, the principles the model espouses are not adequate for solving many problems of great theoretical and practical importance. 3 Generally, a von Neumann model must execute a precise algorithm that can manipulate accurate data. However, lots of problems cannot meet such conditions—for example, accurate data might not be available, or a fixed or static algorithm cannot capture the complexity of the problem under study. Computational models based on natural phe- nomena have gained popularity in recent years. The need to solve a wide range of formidable problems that the prevailing mode of thinking could not solve has prompted the move in this direction. 4 Several recent studies show that na- ture-inspired techniques can potentially solve a wide range of problems and influence future computer design. 5 Some of these techniques are now commonplace and accepted by the wider scientific community. They tend to ex- cel where the knowledge space is ambiguous or incomplete, which is quite common in many real-world applications. Other techniques are more esoteric, such as DNA-based and quantum computation. Many people perceive them to hold the promise for building more powerful massively parallel computers that can provide considerably more computing power than we currently have. This could, of course, help us solve problems con- sidered computationally intractable by today’s standards. This virtual roundtable brings together re- searchers to explore and speculate about the developments in and future directions of their respective fields. The list of topics they explore is by no means exhaustive, but we could extend most of the conclusions to other research fields. I hope that these topics will make you think of the implications of such ideas on developments in your own field. —Albert Y. Zomaya References 1. A. Turing, “On Computable Numbers, with an Application to the Entscheidungsproblem,” Proc. London Mathematical Soc., vol. 43, 1937, pp. 230–265. 2. D. Harel, Algorithmics: The Spirit of Computing, 2nd ed., Addi- son-Wesley, Reading, Mass., 1992. 3. A.K. Dewdney, The New Turing Omnibus, W.H. Freeman, New York, 1993. 4. D. Shasha and C. Lazere, Out of Their Minds: The Lives and Dis- coveries of 15 Great Computer Scientists, Springer-Verlag, New York, 1995. 5. P.J. Denning and R.M. Metcalfe, Beyond Calculation: The Next Fifty Years of Computing, Springer-Verlag, New York, 1997. 82 COMPUTING IN SCIENCE & ENGINEERING NONCONVENTIONAL COMPUTING PARADIGMS IN THE NEW MILLENNIUM: A ROUNDTABLE N ONCONVENTIONAL C OMPUTING BY ALBERT Y. ZOMAYA, JAMES A. ANDERSON, DAVID B. FOGEL, GERARD J. MILBURN, AND GRZEGORZ ROZENBERG 1521-9615/01/$10.00 © 2001 IEEE