10292 Abstracts Collection and Summary -- Resilience Assessment and Evaluation

From July 18 to July 23, 2010 the Dagstuhl Seminar 10292 ``Resilience Assessment and Evaluation \u27\u27 was held in Schloss Dagstuhl~--~Leibniz Center for Informatics. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. The first section describes the seminar topics and goals in general. Links to extended abstracts or full papers are provided, if available

Quantum Steganography via Coherent and Fock State Encoding in an Optical Medium

Steganography is an alternative to cryptography, where information is protected by secrecy -- being disguised as innocent communication or noise -- rather than being scrambled. In this work we develop schemes for steganographic communication using Fock and coherent states in optical channels based on disguising the communications as thermal noise. We derive bounds on their efficiency in the case of an all-powerful eavesdropper, and provide explicit methods of encoding and error correction for the noiseless channel case.Comment: 13 pages, 7 figure

A Hierarchy of Scheduler Classes for Stochastic Automata

Stochastic automata are a formal compositional model for concurrent stochastic timed systems, with general distributions and non-deterministic choices. Measures of interest are defined over schedulers that resolve the nondeterminism. In this paper we investigate the power of various theoretically and practically motivated classes of schedulers, considering the classic complete-information view and a restriction to non-prophetic schedulers. We prove a hierarchy of scheduler classes w.r.t. unbounded probabilistic reachability. We find that, unlike Markovian formalisms, stochastic automata distinguish most classes even in this basic setting. Verification and strategy synthesis methods thus face a tradeoff between powerful and efficient classes. Using lightweight scheduler sampling, we explore this tradeoff and demonstrate the concept of a useful approximative verification technique for stochastic automata