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GRASP Seminar Series: Spring 2008
January 11, 11:00 a.m., Wu & Chen Auditorium, Levine Hall (3330 Walnut Street)
John Doyle
California Institute of Technology
"Rules of engagement: The architecture of robust, evolvable networks"
Abstract: The
nature of complexity, robustness, and evolvability has been a persistent
source of confusion both throughout science and between science and society. Recent
broad progress could potentially help resolve much of this confusion,
particular among those attracted to rigor in experiments, statistics,
and mathematics. This talk will take a hopefully light-hearted
look at the sources of confusion as well their potential resolution.
The technical basis of this talk is on the architectural and organizational principles
of networked systems, building on insights about the fundamental nature of complex
biological and technological networks drawn from three converging research themes. 1)
With molecular biologys description of components and growing attention to systems
biology, the organizational principles of biological networks are becoming increasingly
apparent. Biologists are articulating richly detailed explanations of
biological complexity, robustness, and evolvability that point to universal principles.
2)
Advanced technologys complexity is now approaching biologys. While the components
differ, there is striking convergence at the network level of architecture and
the role of layering, protocols, and feedback control in structuring complex
multiscale modularity. New theories of the Internet and related networking technologies
have led to test and deployment of new protocols for high performance networking. 3)
A new mathematical framework for the study of complex networks suggests that
this apparent network-level evolutionary convergence within/between biology/technology
is not accidental, but follows necessarily from the universal system requirements
to be efficient, adaptive, evolvable, and robust to perturbations in their environment
and component parts.
One of the simplest but most important observations is that biological systems
are robust and evolvable in the face of even large changes in environment and
system components, yet can simultaneously be extremely fragile to small perturbations.
Such universally robust yet fragile (RYF) complexity is found wherever we look.
The amazing evolution of microbes into humans (robustness of lineages on long
timescales) is punctuated by mass extinctions (extreme fragility). Diabetes,
obesity, cancer, and autoimmune diseases are side-effects of biological control
and compensatory mechanisms so robust as to normally go unnoticed. RYF complexity
is not confined to biology. The complexity of technology is exploding around
us, but in ways that remain largely hidden. Modern institutions and technologies
facilitate robustness and accelerate evolution, but enable catastrophes on a
scale unimaginable without them (from network and market crashes to war, epidemics,
and climate change). Understanding RYF means understanding architecture the most
universal, high-level, persistent elements of organization and protocols. Protocols
define how diverse modules interact, and architecture defines how sets of protocols
are organized.
Biography: John
Doyle is the John G Braun Professor of Control and Dynamical Systems,
Electrical Engineer, and BioEngineering at Caltech. He has a BS
and MS in EE, MIT (1977), and a PhD, Math, UC Berkeley (1984). Current
research interests are in theoretical foundations for complex networks
in engineering, biology, and multiscale physics. His group led the development
of the open source Systems Biology Markup Language (SBML) (www.sbml.org),
the analysis toolbox SOSTOOLS (www.cds.caltech.edu/sostools),
and contributed to the theory of the FAST protocol that have broken multiple
world land speed records (netlab.caltech.edu). Early
work was in the mathematics of robust control, LQG robustness, (structured)
singular value analysis, H-infinity plus recent extensions. He
coauthored books and software toolboxes currently used at over 1,000
sites worldwide, the main control analysis tool for high performance
commercial and military aerospace systems, as well as many other industrial
systems. Prize papers include the IEEE Baker, the IEEE Automatic Control
Transactions Axelby (twice), and the AACC Schuck. Individual awards
include the AACC Eckman, and the IEEE Control Systems Field and Centennial
Outstanding Young Engineer Awards. He has held national and world
records and championships in various sports.
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