Dimitrios Hristu-Varsakelis

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—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)
Key establishment protocols are among the most important security mechanisms via which two or more parties can encrypt their communications over an insecure network. This paper is concerned with the vulnerability of one-pass two-party key establishment protocols to key-compromise impersonation (K-CI) attacks. The latter may occur once an adversary has(More)
A Networked Control System (NCS) is a control system in which the sensors and actuators are connected to a feedback controller via a shared communication medium. In an NCS, the shared medium can only provide a limited number of simultaneous connections for the sensors and actuators to communicate with the controller. As a consequence, the design of an NCS(More)