S. Purushothaman Iyer

Learn More
This paper investigates the use of abstract-interpretation-inspired techniques for improving the performance of procedures for determining when systems satisfy formulas in branching-time temporal logic. A framework for abstracting system descriptions is developed, and a particular method for generating abstract systems from given abstractions on system(More)
Remotely-launched software exploits are a common way for attackers to intrude into vulnerable computer systems. As detection techniques improve, remote exploitation techniques are also evolving. Recent techniques for evasion of exploit detection include <i>polymorphism</i> (code encryption) and <i>meta-morphism</i> (code obfuscation). This paper addresses(More)
This paper presents a mu-calculus-based modal logic for describing properties of reactive probabilistic labeled transition systems (RPLTSs) and develops a modelchecking algorithm for determining whether or not states in finite-state RPLTSs satisfy formulas in the logic. The logic is based on the distinction between (probabilistic) “systems” and(More)
ions. In the rest of the paper, we write ALTS to denote thatALTS is an abstraction of a labelled transition system LTS. An abstraction carries with it a natural quasi-ordering v induced by the function and defined by a v b if (a) (b). Furthermore, this quasi-ordering induces a natural equivalence relation = defined by a = b if a v b and b v a. Note that two(More)
We consider the problem of deciding whether an innnite-state system (expressed as a Markov chain) satisses a correctness property with probability 1. This problem is, of course, undecidable for general innnite-state systems. We focus our attention on the model of proba-bilistic lossy channel systems consisting of nite-state processes that communicating over(More)
Net unfoldings have attracted great attention as a powerful technique for combating state space explosion in model checking, and have been applied to verification of finite state systems including 1-safe (finite) Petri nets and synchronous products of finite transition systems. Given that net unfoldings represent the state space in a distributed, implicit(More)
Let ( F’l, Pz, . . . . Pm) be a network of n finite state machines, communicating with each other asynchronously using typed messages over unbounded FIFO channels, In this paper we present a data flow approach to analyzing these communicating machines for nonprogress properties (deadlock and unspecified reception). We set up flow equations to compute the(More)
With software playing an increasingly important role in medical devices, regulatory agencies such as the US Food and Drug Administration need effective means for assuring that this software is safe and reliable. The FDA has been striving for a more rigorous engineering-based review strategy to provide this assurance. The use of mathematics-based techniques(More)