Tivadar Szemethy

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An important problem in the control of complex systems, and one that inherently exhibits hybrid dynamics, is fault management and recovery. If a component fails in a system, the continuous behavior will suddenly change. In an autonomous system, the controller must be adaptive to ensure continued useful operation when faults occur. Fault-adaptive control(More)
—The Internet's universality is based on its decentralization and diversity. However, its distributed nature leads to operational brittleness and difficulty in identifying the root causes of performance and availability issues, especially when the involved systems span multiple administrative domains. The first step to address this fragmentation is(More)
In this paper we argue for UML-based metamodeling and pattern-based graph transformation techniques in computer-based systems development through an illustrative example from the domain of embedded systems. We present a tool that uses advanced graph-rewriting techniques to generate a schedule that satisfies hard real-time constraints for multi-modal(More)
Applying model-based diagnosis techniques to systems that exhibit hybrid behavior presents an interesting set of challenges that mostly revolve around interactions of the continuous and discrete components of the system. In many real world systems, the overall physical plant is inherently continuous, but system control is performed by a supervisory(More)
– Complex control applications require capabilities for accommodating faults in the controlled plant. Fault accommodation involves the detection and isolation of faults, and then taking appropriate control actions to mitigate the fault effects and maintain control. This requires the integration of fault diagnostics with control in a feedback loop. This(More)
– Fault adaptive systems must adapt and reconfigure themselves to the changes in the environment or the system itself, and have to maintain operation even in case of system failures. In order to avoid performance degradation due to system reconfi-gurations, adequate reconfiguration management is necessary. This paper describes a fault-adaptive control(More)
P2P-TV systems have become part of the Internet landscape 1. The architecture of these (normally proprietary) applications is generally receiver-driven, in that receivers actively search for suitable peers to download from, trying to maximize their performance. This results in very aggressive applications that generate huge and non optimized traffic loads.(More)