Browsing by Subject "Mathematical transformations"

Now showing items 1-20 of 45

    • Article  

      Bogoyavlensky-Volterra and Birkhoff integrable systems 

      Damianou, Pantelis A.; Kouzaris, S. P. (2004)
      In this paper we examine an interesting connection between the generalized Volterra lattices of Bogoyavlensky and a special case of an integrable system defined by Sklyanin. The Sklyanin system happens to be one of the ...
    • Article  

      Classification of potential symmetries of generalised inhomogeneous nonlinear diffusion equations 

      Sophocleous, Christodoulos (2003)
      We consider the class of generalised nonlinear diffusion equations f(x)ut = [g(x)unux]x which are of considerable interest in mathematical physics. We classify the nonlocal symmetries, which are known as potential symmetries, ...
    • Article  

      Conditional densities for continuous-time nonlinear hybrid systems with applications to fault detection 

      Hibey, Joseph L.; Charalambous, Charalambos D. (1998)
      Continuous-time nonlinear stochastic differential state and measurement equations, all of which have coefficients capable of abrupt changes at a random time, are considered; finite-state jump Markov chains are used to model ...
    • Article  

      Conformal mapping for the efficient MFS solution of Dirichlet boundary value problems 

      Karageorghis, Andreas; Smyrlis, Yiorgos-Sokratis (2008)
      In this work, we use conformal mapping to transform harmonic Dirichlet problems of Laplace's equation which are defined in simply-connected domains into harmonic Dirichlet problems that are defined in the unit disk. We ...
    • Article  

      Differential invariants of the one-dimensional quasi-linear second-order evolution equation 

      Ibragimov, Nail Kh; Sophocleous, Christodoulos (2007)
      We consider evolution equations of the form ut = f(x, u, ux)uxx + g(x, u, ux) and ut = uxx + g(x, u, ux). In the spirit of the recent work of Ibragimov [Ibragimov NH. Laplace type invariants for parabolic equations. Nonlinear ...
    • Article  

      Efficient MFS algorithms for inhomogeneous polyharmonic problems 

      Karageorghis, Andreas (2011)
      In this work we develop an efficient algorithm for the application of the method of fundamental solutions to inhomogeneous polyharmonic problems, that is problems governed by equations of the form Δ ℓ u=f, ℓ ε ℕ, in circular ...
    • Conference Object  

      Exact filters for Newton-Raphson parameter estimation algorithms for continuous-time partially observed stochastic systems 

      Charalambous, Charalambos D.; Logothetis, Andrew; Hibey, Joseph L. (IEEE, 1999)
      This paper presents explicit finite-dimensional filters for implementing Newton-Raphson (NR) parameter estimation algorithms. The models which exhibit nonlinear parameter dependence are stochastic, continuous-time and ...
    • Conference Object  

      Fast wavelet transform in motor unit action potential analysis 

      Pattichis, Marios S.; Pattichis, Constantinos S. (Publ by IEEE, 1993)
      Wavelet analysis is a new method for analyzing time and frequency contents of signals. We present the Fast Wavelet Transform (FWT) implemented using B-wavelets and non-circular convolutions in the analysis of Motor Unit ...
    • Article  

      Finite Difference Schemes for the Cauchy–Navier Equations of Elasticity with Variable Coefficients 

      Bialecki, B.; Karageorghis, Andreas (2015)
      We solve the variable coefficient Cauchy–Navier equations of elasticity in the unit square, for Dirichlet and Dirichlet-Neumann boundary conditions, using second order finite difference schemes. The resulting linear systems ...
    • Conference Object  

      First passage risk-sensitive criterion for stochastic evolutions 

      Charalambous, Charalambos D.; Hibey, Joseph L. (1995)
      The purpose of this paper is to investigate in an infinite dimensional space, the first passage problem with a risk-sensitive performance criterion, and to illustrate the asymptotic behavior of the associated value function, ...
    • Article  

      Further transformation properties of generalised inhomogeneous nonlinear diffusion equations with variable coefficients 

      Sophocleous, Christodoulos (2005)
      We consider the variable coefficient inhomogeneous nonlinear diffusion equations of the form xput = [xqu nux]x. We present further transformation properties for this nonlinear class of equations that do not appear in the ...
    • Article  

      Group analysis of nonlinear fin equations 

      Vaneeva, Olena O.; Johnpillai, A. G.; Popovych, R. O.; Sophocleous, Christodoulos (2008)
      Group classification of a class of nonlinear fin equations is carried out exhaustively. Additional equivalence transformations and conditional equivalence groups are also found. These enable us to simplify the classification ...
    • Article  

      Hodograph-type transformations 

      Sophocleous, Christodoulos (2003)
      We consider second-order evolution equations of the form ut = F1(u,ux)uxx+F2(u,ux) and third order of the form ut = F1(u,ux)u xxx+F2(u,ux,uxx). For each of these equations we construct point transformations which relate ...
    • Conference Object  

      How fast are the two-dimensional gaussian waves? 

      Baxevani, Anastassia; Podgórski, K.; Rychlik, I. (2002)
      For a stationary two-dimensional random field evolving in time, we derive the intensity distributions of appropriately defined velocities of crossing contours. The results are based on a generalization of the Rice formula. ...
    • Article  

      Information states in stochastic control and filtering: a lie algebraic theoretic approach 

      Charalambous, Charalambos D.; Elliott, R. J. (2000)
      The purpose of this paper is twofold: i) to introduce the sufficient statistic algebra which is responsible for propagating the sufficient statistics, or information state, in the optimal control of stochastic systems and ...
    • Conference Object  

      Is robustness of stochastic uncertain systems related to information theory and statistical mechanics? 

      Charalambous, Charalambos D.; Kyprianou, Andreas (2005)
      Fifty years ago, when Claude Shannon was developing the Mathematical Theory of Communications, for reliable data transmission, which evolved into the subject of information theory, another discipline was developing dealing ...
    • Conference Object  

      Is robustness of stochastic uncertain systems related to information theory and statistical mechanics? 

      Charalambous, Charalambos D.; Kyprianou, Andreas (Affiliation: Department of Electrical and Computer Engineering, University of Cyprus, Nicosia, CyprusAffiliation: Department of Mechanical and Manufacturing Engineering, University of Cyprus, Nicosia, CyprusAffiliation: School of Information Technology and Engineering, University of Ottawa, 161 Louis Pasteur, A519, Ottawa, Ont. K1N 6N5, CanadaCorrespondence Address: Charalambous, C.D.Department of Electrical and Computer Engineering, University of Cyprus, Nicosia, Cyprusemail: chadcha@ucy.ac.cy, 2005)
      Fifty years ago, when Claude Shannon was developing the Mathematical Theory of Communications, for reliable data transmission, which evolved into the subject of information theory, another discipline was developing dealing ...
    • Conference Object  

      Is robustness of stochastic uncertain systems related to information theory and statistical mechanics? 

      Charalambous, C. D.; Kyprianou, Andreas (Affiliation: Department of Electrical and Computer Engineering, University of Cyprus, Nicosia, CyprusAffiliation: Department of Mechanical and Manufacturing Engineering, University of Cyprus, Nicosia, CyprusAffiliation: School of Information Technology and Engineering, University of Ottawa, 161 Louis Pasteur, A519, Ottawa, Ont. K1N 6N5, CanadaCorrespondence Address: Charalambous, C.D.Department of Electrical and Computer Engineering, University of Cyprus, Nicosia, Cyprusemail: chadcha@ucy.ac.cy, 2005)
      Fifty years ago, when Claude Shannon was developing the Mathematical Theory of Communications, for reliable data transmission, which evolved into the subject of information theory, another discipline was developing dealing ...
    • Article  

      A Kansa-Radial Basis Function Method for Elliptic Boundary Value Problems in Annular Domains 

      Liu, X. -Y; Karageorghis, Andreas; Chen, C. S. (2015)
      We employ a Kansa-radial basis function (RBF) method for the numerical solution of elliptic boundary value problems in annular domains. This discretization leads, with an appropriate selection of collocation points and for ...
    • Article  

      Kansa-RBF algorithms for elliptic problems in axisymmetric domains 

      Karageorghis, Andreas; Chen, C. S.; Liu, X. -Y (2016)
      We employ a Kansa-radial basis function method for the numerical solution of elliptic boundary value problems in three-dimensional axisymmetric domains. We consider problems governed by the Poisson equation, the inhomogeneous ...