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We introduce a quantitative concept for bisimulations by integrating the notion of amortisation (cf. [3]). This allows us to make behavioural comparisons between nondeterministic systems that are inherently non-terminating and to analyse the relative long-term costs of deploying them. To this end, we conservatively extend CCS to include a new set of(More)
Return address corruption on the stack using buffer overflow attacks is one of the most common ways in which the security of a system can be compromised. This paper provides a way of detecting return address corruption on the stack using dynamic code instrumentation. The detection is done at run-time and it does not depend on the availability of source code(More)
  • S. Arun-Kumar
  • 2006
In this paper, we give a straightforward generalization of bisimulations to "bisimulations induced by a pair of relations" on the underlying action set. We establish that many of the nice properties of bisimulations and bisimilarities may be thought of as actually being inherited from properties of the underlying relations on actions. We show that many(More)
Preface Students of computer science in IIT Delhi usually take a course on Theory of Computation as an elective some time after they have finished courses on programming, data structures, discrete mathematical structures (whatever that means), computer architecture, programming languages and sometimes operating systems as well. Theory of computation is of(More)
In this paper, we propose an at least as fast as relation between two timed automata states and investigate its decidability. The proposed relation is a prebisimulation and we show that given two processes with rational clock valuations it is decidable to check whether such a prebisimulation relation exists between them. Though bisimulation relations have(More)