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The Carleman formula and recovering the refractive index of the twodimensional Helmholtz equation
(2008)We consider the Cauchy problem for the Helmholtz equation with given bounded refrac tive index in an arbitrary planar domain with Cauchy data only on part of the boundary of the domain. We derive a Carlemantype formula ... 
Constrained pole placement by linear quadratic modification
(IEEE, 19910626)A noniterative method is introduced that will enable the designer to find an optmal one step state feedback controller. The controller will place the eigenvalues of the closed loop system in a specified disk. 
Numerical comparison of negative damping bounds in a specified domain when the wave speed varies
(IEEE, 19920624)The energy decay of a selfexcited wave equation utt  c2 Â¿ u  P(x)ut = 0 is studied where the wave speed c is greater than one, P(x) Â¿ 0, and P(x) LÂ¿(Â¿), Â¿ Â¿ Â¿ Rn. Moreover, the relationship between two bounds for ... 
Numerical methods for RiemannHilbert problems in multiply connected circle domains
(Elsevier Science Inc., 20161201)RiemannHilbert problems in multiply connected domains arise in a number of applications, such as the computation of conformal maps. As an example here, we consider a linear problem for computing the conformal map from the ... 
Pole placement by linear quadratic modification for continuous time systems
(IEEE, 19910626)This paper bridges the gap between linear quadratic solution and pole placement providing a simple criterion sucht that the resulting optimal gain places the closed loop eigenvalues at desired locations. The method has the ... 
Protostellar collapse using multigroup radiation hydrodynamics
(Astronomical Society of the Pacific, 2015)Many simulations of protostellar collapse make use of a grey treatment of radiative transfer coupled to the hydrodynamics. However, interstellar gas and dust opacities present large variations as a function of frequency. ... 
Stability of coupled strings vibration system due to different boundary conditions
(IEEE, 19930602)We study the rate of convergence of a coupled wave systems under two different boundary conditions, energy absorbing in two ends for one and free or fixed boundary controls in two ends for the other one. We will observe ... 
The stabilization of a linearized selfexcited wave equation by an energy absorbing boundary
(IEEE, 19920624)We study the linrized selfexcited wave quation tt  A £ P(s) tg=0, where P(s)>0, P(r)eL(f), in a bounded domain 0cRI with smooth bounar r whee boun y dampig is prst. coniering the prtii Fr 1r.).of he bouM~ ron which ...