Stelios C. A. Thomopoulos

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The problem of optimal data fusion in the sense of the Neyman-pearson (N-P) test in a centralized fusion center is considered. The fusion center receives data from various distributed sensors. Each sensor implements a N-P test individually and independently of the other sensors. Due to limitations in channel capacity, the sensors transmit their decision(More)
Localization of elderly people is considered to be a key task in ambient assisted living platforms. The problem of timely and valid emergency medical services notifications may be addressed in the context of a location-aware, event-triggered system provided an accurate, robust and reliable underlying localization system exists. Furthermore, first(More)
The effects of transmission delay and channel errors on the performance of a distributed sensor system are studied. In a network of distributed sensors at a given time instant, the decisions from some sensors may not be available at the fusion center owing to networking and transmission delays. Assuming that the fusion center has to make a decision on the(More)
A comparative study of two self-organizing clustering neural network algorithms, Dignet and ART2, has been conducted. The differences in architecture and learning procedures between the two models are compared. Comparative computer simulations on data clustering and signal detection problems with Gaussian noise were used for investigating the performance of(More)
This paper addresses the problem of high-resolution parameter estimation (harmonic retrieval) and model-order selection for superimposed sinusoids. The harmonic retrieval problem is analyzed using a nonlinear parameter estimation approach. Estimation is performed using several nonlinear estimators with signals embedded in white and colored Gaussian noise.(More)
The problem of decision fusion in distributed sensor systems is considered. Distributed sensors pass their decisions about the same hypotheses to a fusion center that combines then into a final decision. Assuming that the sensor decisions are independent from each other conditioned on each hypothesis, we provide a general proof that the optimal decision(More)
This paper proposes a routing protocol that jointly exploits location and motion information in a dynamically adjusted way, towards self-adaptability in different combinations of mobility and node density conditions. The protocol employs a metric of the rate at which a packet approaches its destination over a multihop path, as an effect of both the(More)
Location information is a cornerstone for the development of the so-called location-based services. A method for the enhancement of a localization system in terms of achieved accuracy is proposed herein, which can be applied to new as well as existing systems regardless of the underlying localization technique. The method is based on modelling the position(More)