June 2012 - tr-announce - lists.rwth-aachen.de

2012-12: Symbolic Evaluation Graphs and Term Rewriting --- A General Methodology for Analyzing Logic Programs
by Thomas Ströder 29 Jun '12

29 Jun '12

The following technical report is available from http://aib.informatik.rwth-aachen.de: Symbolic Evaluation Graphs and Term Rewriting --- A General Methodology for Analyzing Logic Programs Jürgen Giesl, Thomas Ströder, Peter Schneider-Kamp, Fabian Emmes, and Carsten Fuhs AIB 2012-12 There exist many powerful techniques to analyze termination and complexity of term rewrite systems (TRSs). Our goal is to use these techniques for the analysis of other programming languages as well. For instance, approaches to prove termination of definite logic programs by a transformation to TRSs have been studied for decades. However, a challenge is to handle languages with more complex evaluation strategies (such as Prolog, where predicates like the cut influence the control flow). In this paper, we present a general methodology for the analysis of such programs. Here, the logic program is first transformed into a symbolic evaluation graph which represents all possible evaluations in a finite way. Afterwards, different analyses can be performed on these graphs. In particular, one can generate TRSs from such graphs and apply existing tools for termination or complexity analysis of TRSs to infer information on the termination or complexity of the original logic program.

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2012-09: Quantitative Timed Analysis of Interactive Markov Chains
by Thomas Ströder 29 Jun '12

29 Jun '12

The following technical report is available from http://aib.informatik.rwth-aachen.de: Quantitative Timed Analysis of Interactive Markov Chains Dennis Guck, Tingting Han, Joost-Pieter Katoen, and Martin R. Neuhäußer AIB 2012-09 This paper presents new algorithms and accompanying tool support for analyzing interactive Markov chains (IMCs), a stochastic timed 1 1/2-player game in which delays are exponentially distributed. IMCs are compositional and act as semantic model for engineering formalisms such as AADL and dynamic fault trees. We provide algorithms for determining the extremal expected time of reaching a set of states, and the long-run average of time spent in a set of states. The prototypical tool Imca supports these algorithms as well as the synthesis of ε-optimal piecewise constant timed policies for timed reachability objectives. Two case studies show the feasibility and scalability of the algorithms.

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2012-07: Hackers in Your Pocket: A Survey of Smartphone Security Across Platforms
by Thomas Ströder 29 Jun '12

29 Jun '12

The following technical report is available from http://aib.informatik.rwth-aachen.de: Hackers in Your Pocket: A Survey of Smartphone Security Across Platforms André Egners, Björn Marschollek, and Ulrike Meyer AIB 2012-07 In the past research on smart phone operating system security has been scattered over blog posts and other non-archival publications. Over the last 5 years with advent of Android, iOS and Windows Phone 7, an increasing amount of research has also been published in the academic sphere on individual security mechanisms of the three platfroms. However, for a non-expert it is hard to get an overview over this research area. In this paper, we close this gap and provide a structured easy to access overview on the security features and prior research of the three most popular smartphone platforms: Android, iOS, and Windows Phone 7. In particular, we discuss and compare how each of these platforms uses sandboxing and memory protection, provides code signing, protects service connections, provides application shop security, and handles permissions.

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