• Conference Object  

      Crawler detection: A Bayesian approach 

      Stassopoulou, Athena; Dikaiakos, Marios D. (2006)
      In this paper, we introduce a probabilistic modeling approach for addressing the problem of Web robot detection from Web-server access logs. More specifically, we construct a Bayesian network that classifies automatically ...
    • Article  

      The d-identifying codes problem for vertex identification in graphs: Probabilistic analysis and an approximation algorithm 

      Xiao, Y.; Hadjicostis, Christoforos N.; Thulasiraman, K. (2006)
      Given a graph G(V, E), the identifying codes problem is to find the smallest set of vertices D ⊆ V such that no two vertices in V are adjacent to the same set of vertices in D. The identifying codes problem has been applied ...
    • Article  

      A Family of Resource-Bound Real-Time Process Algebras 

      Lee, I.; Philippou, Anna; Sokolsky, O. (2006)
      The Algebra of Communicating Shared Resources (ACSR) is a timed process algebra which extends classical process algebras with the notion of a resource. It takes the view that the timing behavior of a real-time system depends ...
    • Article  

      Hiding resources that can fail: An axiomatic perspective 

      Philippou, Anna; Sokolsky, O.; Lee, I.; Cleaveland, R.; Smolka, S. A. (2001)
      In earlier work, we presented a process algebra, PACSR, that uses a notion of resource failure to capture probabilistic behavior in reactive systems. PACSR also supports an operator for resource hiding. In this paper, we ...
    • Conference Object  

      A mathematical framework for robust control over uncertain communication channels 

      Charalambous, Charalambos D.; Farhadi, A. (2005)
      In this paper, a mathematical framework for studying robust control over uncertain communication channels is introduced. The theory is developed by 1) Generalizing the classical information theoretic measures to the robust ...
    • Conference Object  

      Maximum likelihood diagnosis in partially observable finite state machines 

      Athanasopoulou, E.; Hadjicostis, Christoforos N. (2005)
      In this paper we develop a probabilistic approach for fault diagnosis in deterministic finite state machines (FSMs). The proposed approach determines whether the FSM under consideration is faulty or not by observing (part ...
    • Conference Object  

      Performance and stability bounds for dynamic networks 

      Koukopoulos, D.; Mavronicolas, Marios; Spirakis, Paul G. (2004)
      In this work, we study the impact of dynamically changing link capacities on the delay bounds of LIS (Longest-In-System) and SIS (Shortest-In-System) protocols on specific networks (that can be modelled as Directed Acyclic ...
    • Conference Object  

      Probabilistic failure diagnosis in finite state machines under unreliable observations 

      Athanasopoulou, E.; Li, N.; Hadjicostis, Christoforos N. (2006)
      In this paper we develop a probabilistic methodology for calculating the likelihood that an observed, possibly corrupted event sequence was generated by two (or more) candidate finite state machines (FSMs) (one of which ...
    • Article  

      A probabilistic reasoning approach for discovering web crawler sessions 

      Stassopoulou, Athena; Dikaiakos, Marios D. (2007)
      In this paper we introduce a probabilistic-reasoning approach to detect Web robots (crawlers) from human visitors of Web sites. Our approach employs a Naive Bayes network to classify the HTTP sessions of a Web-server access ...
    • Article  

      Resources in process algebra 

      Lee, I.; Philippou, Anna; Sokolsky, O. (2007)
      The Algebra of Communicating Shared Resources (ACSR) is a timed process algebra which extends classical process algebras with the notion of a resource. It takes the view that the timing behavior of a real-time system depends ...