• Conference Object  

      Action functional stochastic H∞ estimation for nonlinear discrete time systems 

      Charalambous, Charalambos D.; Farhadi, A.; Djouadi, S. M. (2002)
      This paper presents an action functional, sample path optimization technique, for formulating and solving nonlinear discrete-time stochastic H∞ estimation problems. These H∞ problems are formulated as minimax dynamic games ...
    • Article  

      Classes of nonlinear partially observable stochastic optimal control problems with explicit optimal control laws 

      Charalambous, Charalambos D.; Elliott, R. J. (1998)
      This paper introduces certain nonlinear partially observable stochastic optimal control problems which are equivalent to completely observable control problems with finite-dimensional state space. In some cases the optimal ...
    • Conference Object  

      Nonlinear control design for linear time varying systems 

      Zhang, Youping; Ioannou, Petros A. (1996)
      A new class of linear controllers for linear time varying systems are proposed. These controllers are based on nonlinear tools such as integrator backstepping and nonlinear damping, and on a new filter structure that ...
    • Conference Object  

      Output feedback risk-sensitive control and dynamic games: Small noise limits 

      Charalambous, Charalambos D. (IEEE, 1997)
      This paper employs logarithmic transformations to establish relations between continuous-time nonlinear partially observable risk-sensitive control problems and analogous output feedback dynamic games.
    • Article  

      Performance analysis for a changepoint problem 

      Hibey, J. L.; Charalambous, Charalambos D. (1999)
      Nonlinear stochastic differential equations are used to model a version of the changepoint problem. State estimates of the minimum mean-square-error-type are used in likelihood-ratio tests to detect the time of change. ...
    • Conference Object  

      Performance analysis for a changepoint problem 

      Hibey, Joseph L.; Charalambous, Charalambos D. (IEEE, 1997)
      Nonlinear stochastic differential equations are used to model a version of the changepoint problem. State estimates of the minimum-mean-square-error type are used in likelihood-ratio tests to detect the time of change. We ...
    • Conference Object  

      Relative entropy applied to optimal control of stochastic uncertain systems on hilbert space 

      Ahmed, N. U.; Charalambous, Charalambos D. (2005)
      This paper considers minimax problems, in which the control minimizes the pay-off induced by a measure which maximizes the pay-off over the class of measures described by a relative entropy set between the uncertain and ...
    • Conference Object  

      Robust modification of a new class of adaptive controllers 

      Zhang, Youping; Ioannou, Petros A. (1995)
      Recently, a new class of adaptive control schemes, motivated from nonlinear systems theory, has been proposed for minimum phase linear time invariant plants. Under certain assumptions on the plant transfer function, these ...
    • Article  

      Robustness of nonlinear control systems with respect to unmodeled dynamics 

      Zhang, Y.; Ioannou, Petros A. (1999)
      In theory, it can be established that nonlinear control laws for linear or nonlinear plants can be used to meet strict performance requirements. The success of these control designs in practical situations will very much ...
    • Conference Object  

      Robustness of nonlinear control systems with respect to unmodeled dynamics 

      Zhang, Youping; Ioannou, Petros A. (1996)
      In this paper, we examine the global stability properties of nonlinear controllers in the presence of high frequency unmodeled dynamics. We develop necessary and sufficient conditions for a general class of nonlinear control ...
    • Conference Object  

      State space estimation of a wireless frequency-selective fading channel in Gaussian noise 

      Charalambous, Charalambos D.; Li, X. (2002)
      This paper investigates the possibility of using the state space optimal estimation techniques to estimate the inphase, quadrature and square envelope of a wireless multipath fading channel when the transmitted signal is ...
    • Conference Object  

      Stochastic channel modeling for ad hoc wireless networks 

      Olama, M. M.; Djouadi, S. M.; Charalambous, Charalambos D. (2006)
      Due to nodes mobility and environmental changes in mobile ad hoc networks, the ad hoc channel is time varying and subject to fading. As a consequence of these variations, the statistical characteristics of the received ...
    • Conference Object  

      Stochastic power control for time-varying flat fading wireless channels 

      Olama, M. M.; Shajaat, S. M.; Djouadi, S. M.; Charalambous, Charalambos D. (2005)
      The performance of stochastic optimal power control of time-varying wireless short-term flat fading channels, in which the evolution of the dynamical channel is described by a stochastic state space representation, is ...
    • Article  

      Stochastic power control for wireless networks via SDEs: Probabilistic QoS measures 

      Charalambous, Charalambos D.; Djouadi, S. M.; Denic, S. Z. (2005)
      The power control of wireless networks is formulated using a stochastic optimal control framework, in which the evolution of the channel is described by stochastic differential equations (SDEs). The latter rapture the ...
    • Conference Object  

      Time varying channel modeling for ad-hoc mobile wireless networks 

      Olama, M. M.; Djouadi, S. M.; Charalambous, Charalambos D. (2006)
      Due to nodes mobility and environmental changes in mobile ad-hoc networks, the ad-hoc channel is time varying and subject to fading. As a consequence of these variations, the statistical characteristics of the received ...
    • Conference Object  

      Time varying wireless channel modeling, estimation, identification, and power control from measurements 

      Olama, M. M.; Yanyan, L.; Djouadi, S. M.; Charalambous, Charalambos D. (2007)
      This paper is concerned with a time-varying wireless channel modeling, its parameter estimation, system identification, and optimal power control from measurement data. The channel model is represented in state space form, ...
    • Conference Object  

      Wireless fading channels: Modeling, estimation and identification from measurements 

      Charalambous, Charalambos D.; Bultitude, R. J. C.; Zhan, J.; Papageorgiou, I. G. (2005)
      This paper is concerned with modeling and system identification of wireless channels. The models employed are in state space form, while the identification method uses the Expectation-Maximization (EM) algorithm and Kalman ...