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2003 May Issue 3

RLE Pursues the Optical Clock
Erich P. Ippen at the New Limits of Precision

Multidisciplinary Initiative
the DoD MURI program and RLE

Rising Stars
Oxenham and Sugiyama

Students at the Forefront
The Helen Carr Peake Research Prize

Computational Prototyping
an interview with Jacob K. White

Introducing a New Professor
Luca Daniel joins RLE

Download PDF of Issue 3


an interview with Jacob K. White
(this is an expanded version of the interview appearing in the printed issue of RLE at MIT)
2003 May Issue 3

RLE: What is "computational prototyping?"
White: The notion of prototyping is pervasive in engineering design; one investigates the viability of a new idea by constructing a single implementation, a prototype. Whether the problem is designing an integrated circuit, a micromachined sensor, a new drug, or an off-shore structure, the cost and time required to construct prototypes is high enough to discourage comprehensive design exploration. We refer to the process of substituting computer models for physical prototypes as computational prototyping. The promise of using computational prototyping is that the ease of testing alternative designs will allow designers to examine more radical, and possibly much more efficient, design alternatives. The challenge of computational prototyping is in developing accurate modeling algorithms and techniques which are both flexible and fast enough to allow designers to examine a wide range of design alternatives.

RLE: How did your early research in computer aided design of integrated circuits lead to your current interests?
"The promise of using computational prototyping is that the ease of testing alternative designs will allow designers to examine more radical, and possibly much more efficient, design alternatives." —WhiteWhite: For my PhD, I worked on numerical techniques for improving the efficiency of circuit simulation. I was fascinated by the problem of making numerical techniques effective in a given application, and inspired by the way in which practice so directly followed mathematical theory in the case of circuit simulation. By investigating numerical techniques for other applications, I am hoping to expose students in a variety of engineering and science disciplines to the beauty of marrying mathematical theory with engineering practice.

RLE: What are the special challenges of developing computer aided design tools for mixed signal systems that seek to combine analog and digital processing?
White: When designing digital systems alone, one can improve simulation efficiency by exploiting the existing abstract representations for digital design. For example, one can simulate the behavior of a network of logic gates without simulating each individual transistor in each logic gate, and therefore one can afford to simulate a very complicated sequence of events. Simulating analog systems usually involves simulating the behavior of each individual transistor, either because there is no abstract representation for the circuit of interest, or the abstract representation does not model important second-order effects. Mixed signal simulation is difficult because it is necessary to simulate very complicated sequences of events to test the digital processing, but it is presently too expensive to simulate the analog system's response to those complicated sequences.

RLE: How do you see the techniques that your group is developing being applied to next-generation efforts to integrate micro-machined devices?
White: The most pressing problem for designers is finding simulation tools that make it possible to quickly examine design alternatives. To provide such simulation speed for designs which combine digital processing, analog circuitry, and micromachined devices, it is necessary to generate abstract representations of the analog circuitry and micromachined devices. Since there is such a wide range of analog circuits and micromachined devices, we are following a strategy that numerically generates the abstract representation, by extracting it from either a circuit description or from a three-dimensional geometry.

RLE: Having just recently completed your first year as one of RLE's two Associate Directors, what aspect of your new role has surprised you the most?
White: The rapidly growing economy of the last decade greatly expanded the economic resources available at MIT, but I think we have all been surprised by how much recent economic and political events have changed the situation. Funding of all kinds is scarcer and what is available is harder to get. I have been impressed, though perhaps not surprised, by how RLE investigators have adapted to this difficult situation. RLE investigators have increased their efforts to secure or expand funding sources, and many have volunteered space so as to more economically provide for junior faculty. This heroic effort is taking its toll on RLE investigators, and is reducing time available for research. I am surprised at how difficult it is to determine effective strategies for RLE to help researchers find and raise those funds.

Additional Links
Jacob K. White

Jacob K. White
, Associate Director of RLE and Professor of Electrical Engineering and Computer Science, leads RLE's Computational Prototyping Group. White received his undergraduate degree in electrical engineering and computer science from MIT in 1980, and his masters degree in 1983 and his doctorate in 1985 from the University of California, Berkeley, in the same discipline. He worked at the IBM T. J. Watson Research Center from 1985 to 1987. He joined the MIT faculty in 1987 as assistant professor in EECS, becoming associate professor in 1991 and full professor in 1996. White is a pioneer in numerical methods, particularly in computational prototyping tools and techniques for integrated circuit interconnect, circuit packaging, and micromachined devices. His current research interests include serial and parallel numerical algorithms for problems in circuit, interconnect, and microelectromechanical system design.
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