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Full-Text Articles in Physical Sciences and Mathematics
Optical Machine Recognition Of Lower-Case Greek Characters Of Any Size, Ivan X. D. D'Cunha
Optical Machine Recognition Of Lower-Case Greek Characters Of Any Size, Ivan X. D. D'Cunha
Electrical & Computer Engineering Theses & Dissertations
An algorithm utilizing a syntactic approach and a criterion based on normalized moments is defined for the reliable, automatic, machine recognition of handwritten and printed Greek characters of any size and font. In this approach a binary image of the character in question is obtained initially; its skeleton is then produced by utilizing a standard thinning algorithm. The classification process then incorporates the topological features of the characters such as existence of closed curves, number of intersections, number and location of free ends, axial symmetry, and the criteria derived from normalized moments to uniquely identify each pattern. Experiments conducted demonstrated …
Performance Modeling And Enhancement For The Atamm Data Flow Architecture, Sukhamoy Som
Performance Modeling And Enhancement For The Atamm Data Flow Architecture, Sukhamoy Som
Electrical & Computer Engineering Theses & Dissertations
Algorithm To Architecture Mapping Model (ATAMM) is a new marked graph model from which the rules for data and control flow in a homogeneous, multicomputer, data flow architecture may be defined. This research is concerned with performance modeling and performance enhancement for periodic execution of large-grain, decision-free algorithms in such an ATAMM defined architecture. Performance measures and bounds are established. Algorithm transformation techniques are identified for performance enhancement and reduction of computing element requirements. Operating strategies are developed for optimum time performance and for sub-optimum time performance under limited availability of computing elements. An ATAMM simulator is used to test …
Gaas Photoconductive Closing Switches With High Dark Resistance And Microsecond Conductivity Decay, M. S. Mazzola, K. H. Schoenbach, V. K. Lakdawala, R. Germer, G. M. Loubriel, F. J. Zutavern
Gaas Photoconductive Closing Switches With High Dark Resistance And Microsecond Conductivity Decay, M. S. Mazzola, K. H. Schoenbach, V. K. Lakdawala, R. Germer, G. M. Loubriel, F. J. Zutavern
Electrical & Computer Engineering Faculty Publications
Silicon-doped n-type gallium arsenide crystals, compensated with diffused copper, were studied with respect to their application as photoconductive, high-power closing switches. The attractive features of GaAs:Cu switches are their high dark resistivity, their efficient activation with Nd:YAG laser radiation, and their microsecond conductivity decay time constant. In the authors' experiment, electric fields are high as 19 kV/cm were switched, and current densities of up to 10 kA/cm2 were conducted through a closely compensated crystal. At field strengths greater than approximately 10 kV/cm, a voltage `lock-on' effect was observed.
Nanosecond Optical Quenching Of Photoconductivity In A Bulk Gaas Switch, M. S. Mazzola, K. H. Schoenbach, V. K. Lakdawala, S. T. Ko
Nanosecond Optical Quenching Of Photoconductivity In A Bulk Gaas Switch, M. S. Mazzola, K. H. Schoenbach, V. K. Lakdawala, S. T. Ko
Electrical & Computer Engineering Faculty Publications
Persistent photoconductivity in copper-compensated, silicon-doped semi-insulating gallium arsenide with a time constant as large as 30 µs has been excited by sub-band-gap laser radiation of photon energy greater than 1 eV. This photoconductivity has been quenched on a nanosecond time scale by laser radiation of photon energy less than 1 eV. The proven ability to turn the switch conductance on and off on command, and to scale the switch to high power could make this semiconductor material the basis of an optically controlled pulsed-power closing and opening switch.