Now showing items 1-20 of 96

  • Pole placement by linear quadratic modification for continuous time systems 

    Rousan, N. S.; Sawan, M. Edwin (IEEE, 1991-06-26)
    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 ...
  • Constrained pole placement by linear quadratic modification 

    Rousan, N. S.; Sawan, M. Edwin (IEEE, 1991-06-26)
    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.
  • The stabilization of a linearized self-excited wave equation by an energy absorbing boundary 

    Sarhangi, G.R.; Najafi, M.; Wang, H. (IEEE, 1992-06-24)
    We study the linrized self-excited 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 ...
  • Numerical comparison of negative damping bounds in a specified domain when the wave speed varies 

    Najafi, M.; Sarhangi, G.R.; Sawan, M. Edwin (IEEE, 1992-06-24)
    The energy decay of a self-excited wave equation utt - c2 ¿ u - P(x)ut = 0 is studied where the wave speed c is greater than one, P(x) ¿ 0, and P(x) L¿(¿), ¿ ¿ ¿ Rn. Moreover, the relationship between two bounds for ...
  • Stability of coupled strings vibration system due to different boundary conditions 

    Sarhangi, G.R.; Najafi, M.; Wang, H. (IEEE, 1993-06-02)
    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 ...
  • On the asymptotic behavior of solutions of quasilinear elliptic equations 

    Lancaster, Kirk E.; Stanley, Jeremy (Springer-Verlag, 2003-01-01)
    The asymptotic behavior of solutions of second-order quasilinear elliptic and nonhyperbolic partial differential equations defined on unbounded domains in R n contained in {(Xl, ..., Xn): Ix,~ I < ~(~/x~ +... + x~_ 1)} ...
  • Lipschitz stability in the lateral Cauchy problem for elasticity system 

    Cheng, Jin; Isakov, Victor, 1947-; Yamamoto, Masahiro; Zhou, Qi (Kyoto University, 2003-08-01)
    We consider the isotropic elasticity system: ρ∂2 t u − μ(Δu + ∇(∇Tu))−∇(λ∇Tu) − 3 X j=1 ∇μ · (∇uj + ∂ju)ej = 0 in Ω× (0, T) for the displacement vector u = (u1, u2, u3) depending on x ∈ Ω and t ∈ (0, T) where Ω ...
  • Carleman estimates and applications to inverse problems 

    Isakov, Victor, 1947- (Birkhäuser Verlag Basel/Switzerland, 2004)
    This review paper describes some general and recent results of possible interest for mathematicians studying or using uniqueness of the continuation or working on control theory or inverse problems for partial ...
  • On the existence of convex classical solutions to a generalized Prandtl-Batchelor free boundary problem 

    Acker, Andrew (Birkhäuser Verlag, Basel, 2004)
    Under reasonably general assumptions, we prove the existence of convex classical solutions for the Prandtl-Batchelor free boundary problem in fluid dynamics, in which a flow of constant vorticity density is embedded in ...
  • Spatial autoregression and related spatio-temporal models 

    Ma, Chunsheng (Elsevier Inc., 2004-01)
    We propose a spatial autoregressive randomfield of order p on the spatial domain Rd for pX2 in this paper, whose univariate margins are the continuous-time autoregression of order p on the real line, and introduce a class ...
  • Consistent estimation of distributions with type II bias with applications in competing 

    El Barmi, Hammou; Mukerjee, Hari (Institute of Mathematical Statistics, 2004-02)
    A random variable X is symmetric about 0 if X and -X have the same distribution. There is a large literature on the estimation of a distribution function (DF) under the symmetry restriction and tests for checking this ...
  • Annular capillary surfaces 

    Elcrat, Alan R.; Kim, Tae-Eun; Treinen, Ray (Birkhäuser-Verlag, Basel, 2004-05-01)
    The meniscus in a symmetric annular capillary tube is investigated. The contact angles on the inner and outer tube surface need not be the same. Existence and qualitative properties of solutions are obtained using an ...
  • Increased stability in the continuation of solutions to the Helmholtz equation 

    Hrycak, Tomasz; Isakov, Victor, 1947- (IOP Science, 2004-05-03)
    In this paper we give analytical and numerical evidence of increasing stability in the Cauchy Problem for the Helmholtz equation when frequency is growing. This effect depends on convexity properties of the surface where ...
  • Regularity of the heat operator on a manifold with cylindrical ends 

    Jeffres, Thalia D.; Loya, Paul (Pacific Journal of Mathematics at the University of California, 2004-06-01)
    We study mapping properties of the heat operator etA of an m-th order elliptic b-differential operator in appropriately defined spaces of whole and fractional (Hölder) derivatives. An application is made to short time ...
  • Uniqueness in one inverse problem for the elasticity system 

    Bukhgeım, A. L.; Dyatlov, G. V.; Kardakov, V. B.; Tantserev, E. V. (Plenum Publishing Corporation, 2004-07)
    We consider an inverse problem for the stationary elasticity system with constant Lam´e coefficients and a variable matrix coefficient depending on the spatial variables and frequency. The right-hand side contains a ...
  • The multi-layer free boundary problem for the p-Laplacian in convex domains 

    Acker, Andrew; Henrot, Antoine; Poghosyan, Mikayel; Shahgholian, Henrik (European Mathematical Society, 2004-08-21)
    The main result of this paper concerns existence of classical solutions to the multi-layer Bernoulli free boundary problem with nonlinear joining conditions and the p-Laplacian as gov- erning operator. The present treatment ...
  • Geometry of nonlinear connections 

    Parker, Phillip E.; Del Riego, L. (Elsevier Science B.V., Amsterdam, 2004-08-28)
    We show that locally diffeomorphic exponential maps can be defined for any second-order differential equation, and give a (possibly nonlinear) covariant derivative for any (possibly nonlinear) connection. We introduce ...
  • The use of the variogram in construction of stationary time series models 

    Ma, Chunsheng (Applied Probability Trust, 2004-12)
    This paper studies a class of stationary covariance models, in both the discrete- and the continuous-time domains, which possess a simple functional form γ(τ + τ0) + γ(τ - τ0) - 2γ(τ), where τ0 is a fixed lag and γ(τ) is ...
  • Equilibrium configurations for a floating drop 

    Elcrat, Alan R.; Neel, Robert; Siegel, David (Birkhäuser-Verlag, Basel, 2004-12-01)
    If a drop of fluid of density ρ1 rests on the surface of a fluid of density ρ2 below a fluid of density ρ0, ρ0 < ρ1 < ρ2, the surface of the drop is made up of a sessile drop and an inverted sessile drop which match an ...
  • Schwarz-Christoffel mapping of multiply connected domains 

    Delillo, Thomas. K.; Elcrat, Alan R.; Pfealtzgraff, J. A. (Springer Verlag, 2004-12-01)
    A Schwarz-Christoffel mapping formula is established for polygonal domains of finite connectivity m _> 2 thereby extending the results of Christoffel (1867) and Schwarz (1869) for m = 1 and Komatu (1945), m = 2. A ...