Dimitrios Hristu-Varsakelis

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applies and teaches advanced methodologies of design and analysis to solve complex, hierarchical, heterogeneous and dynamic problems of engineering technology and systems for industry and government. Abstract This work is a continuation of recent efforts aimed at understanding the interplay of control, communication and computation in systems whose sensors,(More)
— As modern control theory attempts to elucidate the complexity of systems that combine differential equations and event-driven logic, it must overcome challenges having to do with limited expressive power as well as practical difficulties associated with translating control algorithms into robust and reusable software. The Motion Description Language (MDL)(More)
supported by the Army Research Office under the ODDR&E MURI97 Program Grant No. DAAG55-97-1-0114 (through Harvard University). This document is a technical report in the CDCSS series originating at the University of Maryland. Abstract— We propose a landmark-based representation of maps to be used for robot navigation and exploration. Our approach is aimed(More)
—We discuss the generation of symbolic feedback control sequences for navigating a sparsely-described and uncertain environment, together with the problem of sensing landmarks sufficiently well to make feedback meaningful. We explore the use of a symbolic control approach for mitigating the lack of a detailed map of the environment and for reducing the(More)
We propose a landmark-based representation of maps to be used for robot navigation and ezploration. Our approach is aimed towards mobile robots that operate over ezpan-sire, imprecisely known terrain without a single "global" map. Instead, a map is pieced together from local terrain and navigation data stored in a directed graph. Each of the graph's(More)
We revisit the problem of " sending information into the future " by proposing an anonymous, non-interactive, server-based Timed-Release Encryp-tion (TRE) protocol. We improve upon recent approaches by Blake and Chan, Hwang et al., and Cathalo et al., by reducing the number of bilinear pairings that users must compute, and by enabling additional(More)