Browsing Biomedical Imaging Lab (Minerva Research Group) by Title
Now showing items 123142 of 210

On approximately optimal H∞ controllers for distributed systems
(Georgia Institute of TechnologyInstitute of Electrical and Electronics Engineers, 198912)The structure of all approximately optimal H∞ controllers for stable distributed plants with rational weights is elucidated. The finite and infinitedimensional parts of these H ∞ controllers are identified. It is shown ... 
On structured tangential NevanlinnaPick interpolation
(Georgia Institute of TechnologyInstitute of Electrical and Electronics Engineers, 199312)This paper is a continuation of the work of BercoviciFoiasTannenbaum (1989,1990) on interpolation problems where the interpolating functions are bounded not in norm but in spectral radius or structured singular values. ... 
On the Affine Heat Equation for NonConvex Curves
(Georgia Institute of TechnologyAmerican Mathematical Society, 199807)In this paper, we extend to the nonconvex case the affine invariant geometric heat equation studied by Sapiro and Tannenbaum for convex plane curves. We prove that a smooth embedded plane curve will converge to a point ... 
On the Computation of Switching Surfaces in Optimal Control: A Gröbner Basis Approach
(Georgia Institute of TechnologyInstitute of Electrical and Electronics Engineers, 200104)A number of problems in control can be reduced to finding suitable real solutions of algebraic equations. In particular, such a problem arises in the context of switching surfaces in optimal control. A powerful new methodology ... 
On the Evolution of the Skeleton
(Georgia Institute of TechnologyInstitute of Electrical and Electronics Engineers, 199909)It is commonly held that skeleton variation due to noise is unmanageable. It is also believed that smoothing, invoked to combat noise, creates no new structures, as in the causality principle for smoothing images. We ... 
On the excitability of second harmonic lamb waves in isotropic plates
(Georgia Institute of TechnologyAmerican Institute of Physics, 20100222)Recent research uses second harmonic waves caused by material nonlinearity to characterize fatigue damage in its early stages. This research investigates this second harmonic Lamb wave generation analytically, using a ... 
On the H∞ Optimal Sensitivity Problem for Systems with Delays
(Georgia Institute of TechnologySociety for Industrial and Applied Mathematics, 19870501)In this paper we extend some of the results of [IEEE Trans. Automat. Control, AC31 (1986), pp. 763–766] to more general delay systems. In particular, we analyze the effect of the interaction of delays and nonminimum phase ... 
On the Laplace–Beltrami Operator and Brain Surface Flattening
(Georgia Institute of TechnologyInstitute of Electrical and Electronics Engineers, 199908)In this paper, using certain conformal mappings from uniformization theory, the authors give an explicit method for flattening the brain surface in a way which preserves angles. From a triangulated surface representation ... 
On the Nonlinear Mixed Sensitivity Problem
(Georgia Institute of TechnologyInstitute of Electrical and Electronics Engineers, 198912)The nonlinear H∞ synthesis theory for the sensitivity minimization problem is extended to the twoblock mixed sensitivity method. The synthesis method is valid for majorizable input/output operators and can be extended to ... 
On the optimal two block H∞ compensators for distributed unstable plants
(Georgia Institute of TechnologyInstitute of Electrical and Electronics Engineers, 199206)In this paper we discuss how the optimal compensator can be calculated in H∞ mixed sensitivity minimization problems for a class of unstable distributed systems. An operator theoretic (skew Toeplitz) approach is taken which ... 
On the sensitivity minimization problem for linear timevarying periodic systems
(Georgia Institute of TechnologySociety for Industrial and Applied Mathematics, 198609)An optimal control problem is formulated in the context of linear, discretetime, periodic systems. The cost is the supremum over all exogenous inputs in a weighted hall of plant inputs. The controller is required to be ... 
On the spectra and invertibility of certain operators in systems theory
(Georgia Institute of TechnologyInstitute of Electrical and Electronics Engineers, 198712)In this paper we study the following kind of problem. Let T be an arbitrary contraction. We will define a certain function which will lead to an explicit procedure for the computation of the isolated spectrum of w(T)w(T)', ... 
On the two block problem for unstable distributed systems
(Georgia Institute of TechnologyInstitute of Electrical and Electronics Engineers, 199012)The H∞ mixed sensitivity minimization problem is solved for a class of unstable distributed systems. The solution is based on an extension of the skew Toeplitz methodology. The key mathematical fact used is that the skew ... 
On the Uniqueness of a Minimal Norm Representative of an Operator in the Commutant of the Compressed Shift
(Georgia Institute of TechnologyAmerican Mathematical Society, 198712)In this note we give a new criterion guaranteeing the uniqueness of a minimal norm representative of a bounded linear operator which commutes with a finite multiplicity shift. We moreover give examples which show that ... 
Optical flow: a curve evolution approach
(Georgia Institute of TechnologyInstitute of Electrical and Electronics Engineers, 199510)A novel approach for the computation of optical flow based on an L 1 type minimization is presented. It is shown that the approach has inherent advantages since it does not smooth the flowvelocity across the edges and ... 
Optimal Mass Transport and Image Registration
(Georgia Institute of TechnologyInstitute of Electrical and Electronics Engineers, 20010713)Image registration is the process of establishing a common geometric reference frame between two or more data sets from the same or different imaging modalities possibly taken at different times. In the context of medical ... 
Particle Filtering for Geometric Active Contours with Application to Tracking Moving and Deforming Objects
(Georgia Institute of TechnologyInstitute of Electrical and Electronics Engineers, 200506)Geometric active contours are formulated in a manner which is parametrization independent. As such, they are amenable to representation as the zero level set of the graph of a higher dimensional function. This representation ... 
Particle Filtering for Registration of 2D and 3D Point Sets with Stochastic Dynamics
(Georgia Institute of TechnologyInstitute of Electrical and Electronics Engineers, 200806)In this paper, we propose a particle filtering approach for the problem of registering two point sets that differ by a rigid body transformation. Typically, registration algorithms compute the transformation parameters by ... 
Particle Filtering with Dynamic Shape Priors
(Georgia Institute of TechnologySpringer Verlag, 200609)Tracking deforming objects involves estimating the global motion of the object and its local deformations as functions of time. Tracking algorithms using Kalman filters or particle filters have been proposed for tracking ... 
Particle Filters for Infinite (or Large) Dimensional State Spaces Part 1
(Georgia Institute of TechnologyInstitute of Electrical and Electronics Engineers, 200605)We propose particle filtering algorithms for tracking on infinite (or large) dimensional state spaces. We consider the general case where state space may not be a vector space, we assume it to be a separable metric space ...