• Conference Object  

      Abrupt and incipient fault isolation of nonlinear uncertain systems 

      Zhang, Xiaodong; Polycarpou, Marios M.; Parisini, T. (2000)
      This paper presents a robust fault diagnosis scheme for abrupt and incipient faults in nonlinear uncertain dynamical systems. A detection and approximation estimator is used for online health monitoring. Once a fault is ...
    • Article  

      Bounds on the number of markings consistent with label observations in petri nets 

      Ru, Y.; Hadjicostis, Christoforos N. (2009)
      In this paper, we consider state estimation in discrete-event systems (DESs) modeled by labeled Petri nets and present upper bounds on the number of system states (or markings) that are consistent with an observed sequence ...
    • Article  

      Certain nonlinear partially observable stochastic optimal control problems with explicit control laws equivalent to LEQG/LQG problems 

      Charalambous, Charalambos D.; Elliott, R. J. (1997)
      This paper is concerned with partially observed stochastic optimal control problems when nonlinearities enter the dynamics of the unobservable state and the observations as gradients of potential functions. Explicit ...
    • Article  

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

      Hibey, J. L.; Charalambous, Charalambos D. (1999)
      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  

      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  

      Coverage analysis of mobile agent trajectory via state-based opacity formulations 

      Saboori, A.; Hadjicostis, Christoforos N. (2011)
      This paper performs coverage analysis of mobile agent trajectory utilizing discrete event system models and employing state-based notions of opacity. Non-deterministic finite automata with partial observation on their ...
    • Conference Object  

      Decentralized state estimation in discrete event systems under partially ordered observation sequences 

      Hadjicostis, Christoforos N.; Seatzu, C. (Institute of Electrical and Electronics Engineers Inc., 2016)
      We consider the problem of decentralized state estimation, where two or more observation sites send information to a coordinator who aims to determine the set of possible current states of a given discrete event system ...
    • Article  

      Delayed observers for linear systems with unknown inputs 

      Sundaram, S.; Hadjicostis, Christoforos N. (2007)
      We present a method for constructing reduced-order state observers for linear systems with unknown inputs. Our approach provides a characterization of observers with delay, which eases the established necessary conditions ...
    • Conference Object  

      Intersection based decentralized diagnosis: Implementation and verification 

      Panteli, M.; Hadjicostis, Christoforos N. (Institute of Electrical and Electronics Engineers Inc., 2013)
      We consider decentralized diagnosis in discrete event systems that are modeled as non-deterministic finite automata and are observed, through distinct natural projection maps, at multiple observation sites. Specifically, ...
    • Conference Object  

      K-detectability in discrete event systems 

      Hadjicostis, Christoforos N.; Seatzu, C. (Institute of Electrical and Electronics Engineers Inc., 2016)
      This paper studies observability in discrete event systems (DES), and introduces and analyzes the property of K-detectability. In particular, a given DES is strongly K-detectable if eventually (after a finite number of ...
    • Article  

      Marking observer in labeled petri nets with application to supervisory control 

      Cabasino, M. P.; Hadjicostis, Christoforos N.; Seatzu, C. (2017)
      In this paper, we consider the problem of marking estimation in labeled Petri nets whose initial marking is known to belong to a given convex set, in the presence of silent transitions (i.e., transitions labeled with the ...
    • Conference Object  

      Marking observer of labeled petri nets with uncertainty in the initial marking 

      Cabasino, M. P.; Seatzu, C.; Hadjicostis, Christoforos N. (2013)
      In this paper we consider marking estimation in labeled Petri nets whose initial marking is known to belong to a given convex set. We allow for silent transitions (i.e., transitions labeled with the empty word) and ...
    • Conference Object  

      New finite-dimensional risk-sensitive filters: Small-noise limits 

      Charalambous, Charalambos D.; Dey, Subhrakanti; Elliott, Robert J. (IEEE, 1997)
      This paper is concerned with continuous-time nonlinear risk-sensitive filters. It is shown that for large classes of nonlinearities entering both the dynamics and measurements, these filters are finite-dimensional, ...
    • Article  

      Nonconcurrent Error Detection and Correction in Fault-Tolerant Linear Finite-State Machines 

      Hadjicostis, Christoforos N. (2003)
      In this paper, we construct fault-tolerant linear finite-state machines (LFSMs) in which error detection and correction can be performed nonconcurrently (e.g., periodically). More specifically, by jointly choosing the state ...
    • Article  

      Opacity-enforcing supervisory strategies via state estimator constructions 

      Saboori, A.; Hadjicostis, Christoforos N. (2012)
      State-based notions of opacity, such as initial-state opacity and infinite-step opacity, emerge as key properties in numerous security applications of discrete event systems. We consider systems that are modeled as partially ...
    • Article  

      Optimal filtering over uncertain wireless communication channels 

      Ma, X.; Djouadi, S. M.; Charalambous, Charalambos D. (2011)
      In this letter, filtering over wireless communication channels subject to packet losses is considered. The packet losses are assumed to follow a Bernoulli distribution. The latter is interpreted as a special case of a ...
    • Conference Object  

      Optimal state estimators for linear systems with unknown inputs 

      Sundaram, S.; Hadjicostis, Christoforos N. (2006)
      We present a method for constructing linear minimum-variance unbiased state estimators for discrete-time linear stochastic systems with unknown inputs. Our design provides a characterization of estimators with delay, which ...
    • Article  

      Partial state observers for linear systems with unknown inputs 

      Sundaram, S.; Hadjicostis, Christoforos N. (2008)
      We consider the problem of constructing partial state observers for discrete-time linear systems with unknown inputs. Specifically, for any given system, we develop a design procedure that characterizes the set of all ...
    • 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. ...
    • Article  

      Performance analysis for a changepoint problem 

      Hibey, J. L.; Charalambos, C. 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. ...