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Event correlation is a service provided by middleware platforms that allows components in a publish/subscribe architecture to subscribe to patterns of events rather than individual events. Event correlation improves the scalability and performance of distributed systems, increases their analyzability, while reducing their complexity by moving functionality(More)
Modern programming environments provide extensive support for inspecting, analyzing, and testing programs based on the algorithmic structure of a program. Unfortunately, support for inspecting and understanding runtime data structures during execution is typically much more limited. This paper provides a general purpose technique for abstracting and(More)
The analysis and characterization of atrial fibrillation requires the previous extraction of the atrial activity from the electrocardiogram, where the independent atrial and ventricular activities are combined in addition to noise. An independent component analysis method is proposed where additional knowledge about the time and statistical structure of the(More)
This contribution addresses the extraction of atrial activity (AA) from real electrocardiogram (ECG) recordings of atrial fibrillation (AF). We show the appropriateness of independent component analysis (ICA) to tackle this biomedical challenge when regarded as a blind source separation (BSS) problem. ICA is a statistical tool able to reconstruct the(More)
This paper upgrades Regular Linear Temporal Logic (RLTL) with past operators and complementation. RLTL is a temporal logic that extends the expressive power of linear temporal logic (LTL) to all ω-regular languages. The syntax of RLTL consists of an algebraic signature from which expressions are built. In particular, RLTL does not need or expose fix-point(More)
Two new logics for verification of hyperproperties are proposed. Hyperproperties characterize security policies, such as noninter-ference, as a property of sets of computation paths. Standard temporal logics such as LTL, CTL, and CTL * can refer only to a single path at a time, hence cannot express many hyperproperties of interest. The logics proposed here,(More)
Thread allocation is an important problem in distributed real-time and embedded (DRE) systems. A thread allocation policy that is too liberal may cause deadlock, while a policy that is too conservative limits potential parallelism, thus wasting resources. However, achieving (globally) optimal thread utilization, while avoiding deadlock, has been proven(More)
We study the problem of thread allocation in asynchronous distributed real-time and embedded systems. Each distributed node handles a limited set of resources, in particular a limited thread pool. Different methods can be invoked concurrently in each node, either by external agents or as a remote call during the execution of a method. In this paper we study(More)
We present a deadlock avoidance algorithm for distributed systems that guarantees liveness. Deadlock avoidance in distributed systems is a hard problem and general solutions are considered impractical due to the high communication overhead. In previous work, however, we showed that practical solutions exist when all possible sequences of resource requests(More)
We examine the problem of inferring invariants for parametrized systems. Parametrized systems are concurrent systems consisting of an a priori unbounded number of process instances running the same program. Such systems are commonly encountered in many situations including device drivers, distributed systems, and robotic swarms. In this paper we describe a(More)