\chapter{Accomplishments and qualifications}\label{accomplishments}

One of the main objectives of the {\sl Information Mechanics} group
(part of the MIT Laboratory for Computer Science) is to explore
fundamental connections between physics and computation.  Within this
broad context, we have systematically worked at developing both the
conceptual and the technological aspects of cellular automata modeling.

\section{Theory and practice}

On the more theoretical side, we have made significant progress in
interpreting fundamental aspects of physical laws and phenomena in terms
of computational processes.  (This ``informatization'' of physics is a
natural continuation of the ``geometrization'' of physics under whose
banner analytical mechanics and relativity developed.) For example, it
can be shown that the basic principles of thermodynamics (such as the
``second law'') naturally arise as soon as one studies {\sl invertible}
computational processes\cite{fredkin,margolus-thesis}, and that phenomena
analogous to those described by special relativity arise
in the macroscopic behavior of {\sl local and uniform}
computational networks\cite{toffoli-lorentz}.

\medskip

Some consequences of this theoretical work provide useful guidelines for
future technologies.

For instance, it is now generally accepted that the amount of energy
dissipated by each elementary logical operation can in principle be made
smaller than any given finite bound\cite{bennett,fredkin}---and, in
particular, smaller than $kT$ (which until recently had been believed to
represent an ultimate lower bound).  Results of this kind are obviously
relevant to the realizability of indefinitely-extended three-dimensional
circuitry.

Also, we have shown that it is in principle possible to realize
universal logic primitives directly out of microscopic {\sl mechanical}
effects---classical or quantum---rather than out of {\sl statistical} effects arising from
the collective behavior of many particles (as in all of
today's computers)\cite{toffoli-crank,margolus-thesis,feynman-computers,feynman-quantum}.
This is of more than theoretical interest, since if present
trends continue, in two or three decades miniaturization will
have reached the scale of individual particles\cite{keys,bate}.

\medskip

On the other hand, some aspects of our theoretical work are already
being applied to technology.  The family of \cam\ machines illustrates
the advantages of maintaining a tight feedback loop between computation
and physics, as well as between theory and technology.  These machines
use conventional components, but interconnect them in a novel way
suggested by certain aspects of physics\cite{cambook,cams}.  Physics
``returns the favor,'' so to speak, and allows them to simulate those
very aspects of physics with a performance many orders of magnitude
higher than traditional architectures.

Indeed, the current flourishing of lattice-gas models for hydrodynamics
was triggered off by a synergetic interaction between theory
and technology.  The forefather of these models is the HPP gas, which
Pomeau had investigated as early as 1976\cite{hpp}, and which we
rediscovered in 1983 while studying invertible cellular automata.
On seeing this gas model running at high speed on a \cam\ machine,
Pomeau realized that what he had conceived primarily as a {\sl
conceptual} model could indeed be turned, by using suitable hardware,
into a {\sl computationally accessible} model, and was stimulated to
look for cellular-automaton rules that would provide better models of
fluids\cite{fhp,fhp2}.


\section{The CAM family}

Simulating cellular automata models on ordinary computers---even
high-performance ones---is unbearably slow.  Cellular automata machines
were introduced to remedy this situation.  The interest with which these
machines were received by the scientific community has led us to spend
much time perfecting and evaluating hardware and software, documenting
methods and results\cite{cam5,pde,vichniac,phys-like}, giving lectures
and demonstrations, and collaborating with research groups interested in
specific applications (cf.\ \cite{packard-wolfram}).  Popular and trade
articles related to \cam\ machines have appeared in {\sl Scientific
American}, {\sl Physics Today}, {\sl High Technology}, {\sl Discover},
{\sl Omni}, {\sl Mosaic}, {\sl Pixel}, {\sl The Atlantic Monthly}, {\sl
Whole Earth Review}, {\sl The New York Times}, and {\sl Electronic
Engineering Times}.  \Cam-5 is on permanent exhibit at the Boston
Computer Museum.

To respond to the many requests from interested parties, we commissioned
from Systems Concepts Inc, San Francisco, CA the production of \cam-6,
with the explicit understanding that, after fulfilling MIT's internal needs,
further output of the production line would be made available to the
scientific community at large, as inexpensively as possible.  This
machine, which plugs into a slot of an {\sc ibm-pc} (or a compatible unit) was
intended as a laboratory for experimentation, a vehicle for the
communication of results, and a medium for real-time, interactive visual
demonstrations.  \Cam-6 is now in regular commercial production, and is
accompanied by extensive software and
documentation\cite{cambook,califano,porter}.

\medskip

In spite of its high performance, \cam-6 can only deal with rather small
models ($\approx 0.25$ Megabits).  In many applications, several orders
of magnitude greater size is desirable.  The success of \cam-6
encouraged us to plan a much larger cellular automata machine,\footnote
        {And also encouraged d'Humi\'eres and collaborators to design a lattice-gas
oriented version of \cam-6 containing interesting technical innovations\cite{rap1}.}
        tentatively called \cam-7.  Initially, this was supposed to be
essentially a scaled-up version of \cam-6, using some large-scale
integration and a faster clock rate\cite{cam7}.  However, in
the course of this design we introduced a number of radical
improvements, and arrived at an architecture---the \cam-8 design of the present
proposal---that is more regular, more powerful, and much more flexible.
We have already evaluated on small prototypes some critical aspects of 
\cam-8, and are now ready to finalize its design in view of full-scale
production. 

\newpage
{\small

\begin{center}
{\bf Tommaso Toffoli}

Short Resume, May 1988
\end{center}

{\bf Personal}
\begin{tightlist}\item
{\em Address:\/} MIT Laboratory for Computer Science, 545 Technology Square,
Cambridge MA 02139 \\
{\em Phone:\/} (617)-253-3194 \\
{\em Date of Birth:\/} June 22, 1943 \\
{\em Social Security Number:\/} 299-54-6753 \\
Member, Sigma Xi
\end{tightlist}

{\bf Education}

\makebox[0.5em]{}
 \begin{tabular}{llll}
  University of Rome, Italy    & Doctor & Physics & 1967 \\
  The University of Michigan, Ann Arbor, MI & Ph.D.  & Comp.\ and Communic.\ Sci. & 1977
 \end{tabular}

{\bf Research Interests}
\begin{tightlist}\item
 Foundations and physical aspects of computing.  Computer architectures
for massive parallel computation.  Certain areas of artificial
intelligence chiefly concerned with control and pattern recognition.

\end{tightlist}

{\bf Employment}
\begin{tightlist}
\item[-] 1986--present: Principal Research Scientist, Lab.\ for Comp.\ Sci., Mass.\ Inst.\ of Technology.

\item[-] 1978--86: Research Associate,  Lab.\ for Comp.\ Sci., Mass.\ Inst.\ of Technology.

\item[-] 1976--77: Researcher, Institute for the Applications of Computation, National Research
Council, Rome, Italy.
\end{tightlist}

{\bf Relevant Experience}
\begin{tightlist}\item

Pioneered the idea of cellular automata as models of physics (Ph.D. Thesis on ``Cellular
Automata Mechanics,'' 1977).

Developed a series of cellular automata machines (1982-88), of which the latest (\cam-6) is in
commercial production as of 1986 and is used by hundreds of investigators.

Wrote (with N.  Margolus) a comprehensive book on cellular automata as a
modeling environment\cite{cambook} (1987).

Was one of the main developers of the theory of invertible cellular automata and
reversible computation (1976--to date). Has produced a number of original research
ideas that are beginning to identify a new discipline, namely ``Information Mechanics.''

Consulted for industry on real-time control and interfacing (1984--86).

Co-organized three conferences, on ``Physics of
Computation''\cite{endicott} (MIT, 1981), ``Cellular
Automata''\cite{los-alamos} (Los Alamos, 1983), and ``Cellular Automata
'86''\cite{ca86} (MIT, 1986)

Over 50 invited talks on reversible and nondissipative computation, cellular automata
machines, and physical modeling by cellular automata.

Publications: 15 papers in refereed journals and proceeding, 5 in nonrefereed ones, 7 technical
reports, 2 books, all related to cellular automata, cellular automata machines, and physical
modeling.

Regular referee for {\em Physica D}, the National Science
Foundation, and other journals and agencies, on subjects such as cellular
automata, reversible computing, and physical aspects of computation

Earlier research projects: River modeling; physical limits to computation.

\end{tightlist}

\newpage

\begin{center}
{\bf Michael L. Dertouzos}

Short Resume, December 1987
\end{center}

{\bf Personal}
\begin{tightlist}\item
{\em Address:\/} MIT Laboratory for Computer Science, 545 Technology Square,
Cambridge MA 02139 \\
{\em Phone:\/} (617)-253-2145 \\
{\em Date of Birth:\/} November 5, 1936 \\
{\em Social Security Number:\/} 276-36-1689 \\
\end{tightlist}

{\bf Education}

\makebox[0.5em]{}
 \begin{tabular}{llll}
Mass.\ Inst.\ of Technology & Ph.D. & Electrical Eng. & 1964 \\
University of Arkansas & S.M. & Electrical Eng. & 1959 \\
University of Arkansas & B.S. & Electrical Eng. & 1957
 \end{tabular}

{\bf Research Interests}
\begin{tightlist}\item
Multiprocessor systems
\end{tightlist}

{\bf Employment}
\begin{tightlist}
\item[-] 1974--present: Director, Laboratory for Computer Science, Mass.\ Inst.\ of Technology.

\item[-] 1974--present: Professor of Comp.\ Sci.\ and Electr.\ Eng., Electr.\ Eng.\ and Comp.\ Sci.\
Dept., Mass.\ Inst.\ of Technology.

\item[-] 1968--73: Associate Professor, Electr.\ Eng.\ and Comp.\ Sci.\
Dept., Mass.\ Inst.\ of Technology.

\item[-] 1964--68: Assistant Professor, Electr.\ Eng.\ and Comp.\ Sci.\
Dept., Mass.\ Inst.\ of Technology.

\item[-] 1961--64: Research Assistant, Electr.\ Eng.\ and Comp.\ Sci.\
Dept., Mass.\ Inst.\ of Technology.

\item[-] 1958--61: Head, Research and Development, Baldwin Electronics, Inc.
\end{tightlist}

{\bf Relevant Experience}
\begin{tightlist}\item

Serves on two major computer companies' Scientific Advisory Boards.

Author of several texts in computer science and electrical engineering.

Patentee in filed.

Author of papers and articles on multiprocessor systems.

Founder of Computek, Inc., and designer of several commercial computer systems.

\end{tightlist}

\newpage
\begin{center}
{\bf Norman H. Margolus}

Short Resume, May 1988
\end{center}

{\bf Personal}
\begin{tightlist}\item
{\em Address:\/} MIT Laboratory for Computer Science, 545 Technology Square,
Cambridge MA 02139 \\
{\em Phone:\/} (617)-253-2614 \\
{\em Date of Birth:\/} July 29, 1955 \\
{\em Social Security Number:\/} 018-62-6303 \\
\end{tightlist}

{\bf Education}

\makebox[0.5em]{}
 \begin{tabular}{llll}
  Massachusetts Institute of Technology, Cambridge, MA & Ph.D.  & Physics & 1987\\
  University of Alberta, Canada    & B.Sc.(Honours) & Physics & 1977
 \end{tabular}

{\bf Research Interests}
\begin{tightlist}\item
  Physical bases of computation and computational modeling of physics.
Reversible computation.  Quantum computation.  Cellular automata machine
architectures.
 \end{tightlist}

{\bf Employment}
\begin{tightlist}
\item[-] 1988: Research Associate, Lab.\ for Comp.\ Sci., Mass.\ Inst.\ of Technology.

\item[-] 1981--87: Research Assistant,  Lab.\ for Comp.\ Sci., Mass.\ Inst.\ of Technology.

\item[-] 1979--80: Research Assistant,  Center for Theor.\ Physics, Mass.\ Inst.\ of Technology.

\item[-] 1977--78: Systems Programmer/Analyst, Division for Educational
Research, U.\ of Alberta, Edmonton, Canada.
\end{tightlist}

{\bf Relevant Experience}
\begin{tightlist}\item

First to show that reversible cellular automata can model computation in
a practicable manner (Ph.D.\ Thesis on ``Physics and Computation,''
1987). 

Worked with Tommaso Toffoli on developing cellular automata machines
(1982--1988).

Co-authored (with T.\ Toffoli) a book on the use of cellular automata
and cellular automata machines (such as our \cam-6) for modeling. 

Used my reversible cellular automata models as the basis for the first
quantum mechanical models of parallel computation\cite{margolus-quantum}.

A number of invited talks on physics and computation, including several
to Feynmann's ``Physics of Computation'' class at Cal.\ Tech., as well
as one to the New York Academy of Sciences and an upcoming talk at a
``Les Houches'' physics school.

Publications: 4 papers in refereed journals and proceedings, 3 in
non-refereed proceedings, 2 technical reports, 2 books, all related to
cellular automata, cellular automata machines, and physical modeling.

\end{tightlist}

}


