• Conference Object  

      Resolution of initial-state in security applications of des 

      Hadjicostis, Christoforos N. (2012)
      A non-deterministic labeled finite automaton is initial-state opaque if the membership of its true initial state to a set of secret states S remains opaque (i.e., uncertain) to an intruder who observes system activity ...
    • Article  

      Simple declarative language for describing narratives with actions 

      Kakas, Antonis C.; Miller, Rob (1997)
      We describe a simple declarative language E for describing the effects of a series of action occurrences within a narrative. E is analogous to Gelfond and Lifschitz's Language A and its extensions, but is based on a different ...
    • Article  

      Stochastic testing of finite state machines 

      Hadjicostis, Christoforos N. (2001)
      This paper discusses an approach that uses statistical observations about the steady-state behavior of a finite state machine (FSM) in order to detect and identify permanent failures in its state transition mechanism. The ...
    • Article  

      Verification of detectability in Probabilistic Finite Automata 

      Keroglou, C.; Hadjicostis, Christoforos N. (2017)
      In this paper we analyze state estimation in stochastic discrete event systems (SDES) that can be modeled as probabilistic finite automata (PFAs). For a given PFA, we obtain the necessary and sufficient conditions that ...
    • Conference Object  

      Verification of infinite-step opacity and analysis of its complexity 

      Saboori, A.; Hadjicostis, Christoforos N. (2009)
      In this paper, we formulate, analyze, and devise methodologies to verify the notion of infinite-step opacity in discrete event systems that are modeled as (possibly non-deterministic) finite automata with partial observation ...
    • Article  

      Verification of K-step opacity and analysis of its complexity 

      Saboori, A.; Hadjicostis, Christoforos N. (2011)
      Motivated by security and privacy considerations in a variety of applications of discrete event systems, we describe and analyze the computational complexity required for verifying the notion of K-step opacity for systems ...