Eleftherios Matsikoudis

Learn More
Dataflow models of computation have intrigued computer scientists since the 1970s. They were first introduced by Jack Dennis as a basis for parallel programming languages and architectures, and by Gilles Kahn as a model of concurrency. Interest in these models of computation has been recently rekindled by the resurrection of parallel computing, due to the(More)
Deterministic timed systems can be modeled as fixed point problems [15], [16], [4]. In particular, any connected network of timed systems can be modeled as a single system with feedback, and the system behavior is the fixed point of the corresponding system equation, when it exists. For delta-causal systems, we can use the Cantor metric to measure the(More)
Timed concurrent systems are used in concurrent and distributed real-time software, modeling of hybrid systems, design of hardware systems (using hardware description languages), discrete-event simulation, and modeling of communication networks. They consist of concurrent components that communicate using timed signals, which are sets of (semantically)(More)
We ask whether strictly causal components form well defined systems when arranged in feedback configurations. The standard interpretation for such configurations induces a fixed-point constraint on the function modelling the component involved. We define strictly causal functions formally, and show that the corresponding fixed-point problem does not always(More)
Timed discrete-event (DE) is an actor-oriented formalism for modeling timed systems. A DE model is a network of actors consuming/producing timed events from/to a set of input/output channels. In this paper we study a basic DE model, called deterministic DE (DDE), where actors are simple constant-delay components, and two extensions of DDE: NDE, where actors(More)
Interleaving theories have traditionally failed to integrate a satisfactory treatment of the so-called “finite delay property”. This is generally attributed to the expansion law of such theories, but actually, the problem is rooted in the concept of labelled transition system. We introduce a new type of system, in which, instead of labelled transitions, we(More)
We consider end-to-end latency specifications for hard real-time embedded systems. We introduce a discrete-event programming model generalizing such specifications, and address its schedulability problem for uniprocessor systems. This turns out to be rather idiosyncratic, involving complex, time-dependent release predicates and precedence constraints, quite(More)
Interleaving theories have traditionally failed to integrate a satisfactory treatment of the so-called “finite delay property”. This is generally attributed to the expansion law of such theories, but in truth, the problem is rooted in the concept of labelled transition system. We introduce a new type of system, in which, instead of labelled transitions, we(More)