Nikitas A. Alexandridis

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In this paper, we propose a unified model for indexing and retrieving multimedia data using characteristic features and multiresolution processing. All multimedia data types, such as audio and video, are represented as a k-dimensional signal in a spatio-temporal domain [3]. A k-dimensional signal is transformed into characteristic features and these(More)
The explosive increase in the amounts of image and multimedia data being generated, processed, and used in several computer applications have necessitated the development of image and multimedia database systems with newer features such as content-based indices and similarity searches. This paper presents a scheme for content-based retrievals in image(More)
In this paper, two quad-tree (QT) based-dynamic processor allocation/deallocation heuristic algorithms are proposed for a partitionable Mesh-connected parallel multicomputer: the QTTL (Quad Tree Top Left) and the QTR (Quad Tree Root) partition first heuristics. For each QT-based algorithm, a theoretical analysis of its computational time complexity is(More)
In this paper, we overview general hardware architecture and a programming model of SRC-6E TM reconfigurable computers, and compare the performance of the SRC-6E machine vs. Intel® Pentium IV TM. SRC-6E execution time measurements have been performed using three different approaches. In the first approach, the entire end-to-end execution time is taken into(More)
Job Management Systems (JMSs) efficiently schedule and monitor jobs in parallel and distributed computing environments. Therefore, they are critical for improving the utilization of expensive resources in high-performance computing systems and centers, and an important component of grid software infrastructure. With many JMSs available commercially and in(More)
In this paper, we propose a parallel, unified model for the indexing and retrieval by content of multimedia data using a weighted cascade. [4] Each multimedia data type can be viewed as k-dimensional (k-d) data in spatio-temporal domain. [3] Each dimension of the data is separated into small blocks and then formed into a multidimensional tree structure,(More)
Distributed reconfigurable resources, such as FPGA-based accelerator boards 1 are expensive and often underutilized. Therefore, it is important to permit sharing these resources at least among the members of the same organization. Traditional resources, such as CPU time of loosely coupled workstations can be shared using a variety of existing distributed(More)