{"id":266,"date":"2021-03-15T12:43:28","date_gmt":"2021-03-15T16:43:28","guid":{"rendered":"https:\/\/people.clas.ufl.edu\/hager\/?page_id=266"},"modified":"2026-03-19T08:18:25","modified_gmt":"2026-03-19T12:18:25","slug":"fifth-siam-conference-on-control-and-its-applications","status":"publish","type":"page","link":"https:\/\/people.clas.ufl.edu\/hager\/fifth-siam-conference-on-control-and-its-applications\/","title":{"rendered":"Fifth SIAM Conference on Control and Its Applications"},"content":{"rendered":"\r\n
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Fifth SIAM Conference on Control and Its Applications<\/h1>\n\n\n\n

Fifth SIAM Conference on Control and Its Applications
\n July 11 – 14, 2001
\n Town & Country Hotel, San Diego, CA<\/p>\n\n\n\n\n\n

The SIAM Activity Group on Control and Systems Theory joined
\nforces with the SIAM Annual Meeting in hosting the Fifth
\nSIAM Conference on Control and Its Applications in San
\nDiego. Short courses on Flow Control by Max Gunzburger and
\non Shape Optimization by Michel Delfour preceded the
\nconference, setting the stage for a program that included 84
\nminisymposia and 13 invited presentations. The conference
\nliterally kicked off with a plenary talk by Raffaello
\nD’Andrea on cooperative control, a field dealing with the
\ncontrol of entities that exchange information while working
\ntowards an overall group objective. Highlights of the talk
\nwere video clips of Cornell’s world championship robotics
\nsoccer victories in 1999 (Stockholm) and 2000 (Melbourne).
\nD’Andrea attributed their RoboCup victories to the
\nincorporation of optimal control techniques in their team
\nstrategies. In the first joint session with the annual
\nmeeting, Jerry Marsden explained the role of celestial
\ndynamics in trajectory design for space missions, focusing
\non the role of three and four body problems. The theory was
\nillustrated in the context of the upcoming Genesis mission
\nwhich collects solar wind samples and brings them to earth.
\nInvariant manifolds, periodic orbits, and the equilibrium
\npoints of the three body problem were introduced, and saddle
\npoint controllers for remaining on the so-called halo orbit
\nwere described. In the second joint session, P. Kumar
\nexamined wireless communication networks. In the wireless
\nenvironment, packets can be relayed from node to node. When
\na node broadcasts its own information, it can also interfere
\nwith the broadcasts of other nodes. One of many observations
\nof Kumar might be paraphrased in the following way: the
\nmost information is passed through the network when the
\nbroadcast range of each node is as small as possible without
\ndisconnecting the network. Gilbert Strang, in the address
\nof the outgoing president, also sought to unify the annual
\nmeeting with the control conference by providing a linear
\nalgebra view of the well-known Kalman filter, observing
\nthat Kalman’s filter was essentially a statement about
\ntridiagonal matrices and their factorization.<\/p>\n\n\n\n\n\n

Two prizes were given at the conference. First, the W. T.
\nand Idalia Reid Prize in Mathematics was given to Eduardo
\nSontag in honor of his contributions to nonlinear control
\ntheory. In his talk following the prize presentation,
\nSontag examined “Feedback Control Theory and the Challenges
\nof Postgenomic Molecular Biology.” Now that the genomes of
\nmany species are substantially mapped, and the structure of
\nthe encoded proteins are being solved for, the next step is
\nto develop a “systems molecular biology” to characterize
\nthe behavior of complete cellular signal pathways. The
\nscientific and medical payoff of such knowledge will
\nliterally change our understanding of life and result in
\nrevolutionary therapies. A major effort involving the
\nbiology, computer science, chemistry, and physics
\ncommunities is under way in this direction, and Sontag
\ndiscussed in his lecture the potential role to be played by
\nconcepts and techniques from feedback control theory.<\/p>\n\n\n\n\n\n

The second prize, awarded by the control activity group to a
\nyounger researcher, was given to Vincent Blondel for his
\nresearch at the interface between system theory and
\ncomputational complexity theory. His work on the
\ncomputational complexity of problems ranging from the robust
\nstability of time-varying linear systems to controllability
\nof hybrid systems to stability of saturated linear systems
\naddressed fundamental problems in systems and control theory
\nfrom a novel point of view, delineating the limitations of
\nmathematical analysis and computation in certain contexts.
\nAs an illustration in his talk, he observed that easy to
\nstate problems concerning the growth of products of matrices
\nor the decay of solutions of dynamical systems were
\nundecidable. That is, there is no algorithm that always
\nhalts with the right answer.<\/p>\n\n\n\n\n\n

Although optimal control emerged initially in the context of
\ndifferential equations, applications soon advanced to
\npartial differential equations including the pioneering work
\nof J. L. Lions on a variety of topics ranging from impulse
\ncontrol to decomposition methods. Lions, who passed away
\nrecently, was remembered by Tom Banks before the Reid Prize
\nlecture was given. The short courses on flow control and
\nshape optimization at the start of the conference were
\nfollowed by a series of related minisymposia. As one might
\nexpect, flow control involves the application of optimal and
\nfeedback control in the design of optimal flows around
\nobjects. The minisymposia approached this field via
\nnumerical methods (reduction of these high dimensional
\ncomplex problems to lower dimensions using reduced order
\nmodels or proper orthogonal decompositions) and a rich
\nvariety of applications from chemical vapor deposition to
\nair flow around a wing.<\/p>\n\n\n\n\n\n

The plenary talk of Olivier Pironneau provided a survey of
\nthe huge, growing, and difficult field of shape
\noptimization. Applications are pervasive, from structural
\ndesign problems (design a bridge in order to maximize the
\nminimal wind velocity that causes oscillation), to the
\ndesign of ship hulls to minimize drag, to the design of low
\nweight solar collectors for satellites.<\/p>\n\n\n\n\n\n

Another research direction in PDE control showcased at the
\nconference concerns the control of interactive structures.
\nThese structures, surveyed in the plenary lecture of Irena
\nLasiecka, are described by systems of PDEs with coupling
\nterms on interfaces. For example, the equations of
\nelasticity might be coupled at the boundary (interface) with
\nthe plate or shell equation, a typical configuration in
\nstructural acoustic control problems with smart actuators
\nand sensors. One may also consider additional coupling with
\nthe heat equation in describing a thermoelastic system whose
\nelastic properties are modified by heating effects. These
\ncouplings lead to a new class of control models with a
\nstrong mixture of hyperbolic and parabolic characteristics.
\nNew theory exploiting propagation of hyperbolicity and
\nsmoothing effects due to parabolicity were used to describe
\nstabilization and controllability properties.<\/p>\n\n\n\n\n\n

John Betts, an aerospace engineer from Boeing, provided an
\nindustrial facet to the conference. Betts discussed
\npractical issues that arise when trying to solve control
\nproblems with “black box” dynamics. That is, in
\nindustrial applications, the equations that model a physical
\nprocess may be quite complicated. The engineer is given, in
\nessence, a black box describing the system, which must be
\ncontrolled or optimized. Numerical issues in optimal
\ncontrol were highlighted in the talks of Assen Dontchev and
\nFredi Troeltzsch from both the ODE and PDE viewpoint.
\nDontchev focused on the role of solution regularity and
\nLipschitzian stability in the derivation of error estimates
\nfor discretizations, using splines and state constrained
\nproblems for illustrations. Troeltzsch noted that certain
\nembeddings, valid in 1 dimension, break down in higher
\ndimensions, leading to a more complicated analysis involving
\nbootstrapping arguments. Troeltzsch’s talk concluded with a
\nmovie (the North American premier) of an optimally cooled
\nsteel beam.<\/p>\n\n\n\n\n\n

A talk with a strong applied component, given by Ralph
\nSmith, explained how hysteresis and inherent nonlinearities
\ncan be accommodated in the design of systems which utilize
\nsmart materials. The atomic force microscope, an instrument
\nrequiring nanoscale precision, was used as a motivating
\napplication. Smith pointed out the crucial importance of
\ncollaboration between mathematicians and engineers in the
\ndevelopment of effective control strategies that are backed
\nup by rigorous mathematical theory.<\/p>\n\n\n\n\n\n

Another facet of the conference addressed algebra and
\noperator theoretical issues, culminating in the invited
\naddress of William Helton on matrix inequalities and
\ncomputer assisted analysis. In his talk he showed how
\nmatrix inequalities arise and he sketched recent
\ndevelopments of symbolic methods for automatically
\ndetermining if a given function of matrices is “matrix
\nconvex.” Helton’s talk concluded with the following short
\nsummary of the conference: “it was fun.”<\/p>\n\n\n\r\n\t\t\t<\/div>\r\n\t\t<\/div>\r\n\t<\/div>\r\n<\/section>\r\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":1075,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false,"featured_post":"","footnotes":"","_links_to":"","_links_to_target":""},"class_list":["post-266","page","type-page","status-publish","hentry"],"acf":[],"_links":{"self":[{"href":"https:\/\/people.clas.ufl.edu\/hager\/wp-json\/wp\/v2\/pages\/266","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/people.clas.ufl.edu\/hager\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/people.clas.ufl.edu\/hager\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/people.clas.ufl.edu\/hager\/wp-json\/wp\/v2\/users\/1075"}],"replies":[{"embeddable":true,"href":"https:\/\/people.clas.ufl.edu\/hager\/wp-json\/wp\/v2\/comments?post=266"}],"version-history":[{"count":2,"href":"https:\/\/people.clas.ufl.edu\/hager\/wp-json\/wp\/v2\/pages\/266\/revisions"}],"predecessor-version":[{"id":803,"href":"https:\/\/people.clas.ufl.edu\/hager\/wp-json\/wp\/v2\/pages\/266\/revisions\/803"}],"wp:attachment":[{"href":"https:\/\/people.clas.ufl.edu\/hager\/wp-json\/wp\/v2\/media?parent=266"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}