Timing anomalies are characterized by counterintuitive timing behaviour. A locally faster execution leads to an increase of the execution time of the whole program. The presence of such behaviour makes WCET analysis more difficult: It is not safe to assume local worst-case behaviour wherever the analysis encounters uncertainty. Existing definitions of… (More)
Automata over infinite words provide a powerful framework, which we can use to solve various decision problems. However, the autom-atized reasoning with restricted classes of automata over infinite words is often simpler and more efficient. For instance, weak deterministic Büchi automata, which recognize the ω-regular languages in the Borel class Fσ ∩ G δ ,… (More)
Automata are a useful tool in infinite state model checking, since they can represent infinite sets of integers and reals. However, analogous to BDDs to represent finite sets, an obstacle of an automata-based set representation is the sizes of the automata. In this paper, we generalize the notion of " don't cares " for BDDs to word languages as a means to… (More)
— Hard real-time systems need methods to determine upper bounds for their execution times, usually called worst-case execution times. Timing anomalies are counter-intuitive conditions in which a local speed-up of an instruction results in a global slowdown. Modern efficient timing analysis tools may yield inaccurate results when applied to processors with… (More)
Many applications in e-learning utilize wireless networks (WLAN) as a carrier for data and communication. These networks in their basic form are unsecured, protecting the communication is a pre-condition for using a WLAN for confidential contents. Many existing solutions either do not provide the necessary security or fail when employed with large user… (More)
The implementation of the Point to Point Tunneling Protocol (PPTP) from Microsoft using MS-CHAPv2 and Microsoft Point to Point Encryp-tion (mppe) is widely used to secure and control access to wireless networks. We show why the MS-CHAPv2 protocol is not suitable for user authentication in a heterogenous Unix network context.
Google Chrome has implemented a number of " HTML5 " APIs, including the Geolocation API and various storage APIs. In this paper we discuss some of our experiences on the Google Chrome team in implementing these APIs, as well as our thoughts around privacy for new APIs we are considering implementing. Specifically, we discuss our ideas of how providing… (More)
Automata-based decision procedures have proved to be a particularly useful tool for infinite-state model checking, where automata are used to represent sets of real and integer values. However, not all theoretical aspects of these decision procedures are completely understood. We establish triple exponential upper bounds on the automata size for was… (More)