Dimitrios Hristu-Varsakelis

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We revisit the problem of “sending information into the future” by proposing an anonymous, non-interactive, server-based Timed-Release Encryption (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)
Recent advances in mobile phone technology have placed an impressive array of sensing and communication equipment at the hands of an ever-growing number of people. One of the areas which can potentially be transformed by the availability of what is essentially a cheap, ubiquitous networked sensor, is that of remote diagnosis of movement disorders, such as(More)
We discuss Kalman filtering and LQ optimal control of a networked control system (NCS) whose sensors and actuators exchange information with a remote controller over a shared communication medium. Access to that medium is governed by a pair of periodic communication sequences. Under the proposed model, the controller and plant handle communication(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)
With an ever-growing number of technologically advanced methods for the diagnosis and quantification of movement disorders, comes the need to assess their accuracy and see how they match up with widely used standard clinical assessment tools. This work compares quantitative measurements of hand tremor in twenty-three Parkinson's disease patients, with their(More)
The aim of this study is to propose a practical smartphone-based tool to accurately assess upper limb tremor in Parkinson's disease (PD) patients. The tool uses signals from the phone's accelerometer and gyroscope (as the phone is held or mounted on a subject's hand) to compute a set of metrics which can be used to quantify a patient's tremor symptoms. In a(More)