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Electrical and Computer Engineering
Electrical and Computer Engineering Faculty Research and Publications
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Full-Text Articles in Engineering
The Effect Of Pruning And Compression On Graphical Representations Of The Output Of A Speech Recognizer, Yang Liu, Mary P. Harper, Michael T. Johnson, Leah H. Jamieson
The Effect Of Pruning And Compression On Graphical Representations Of The Output Of A Speech Recognizer, Yang Liu, Mary P. Harper, Michael T. Johnson, Leah H. Jamieson
Electrical and Computer Engineering Faculty Research and Publications
Large vocabulary continuous speech recognition can benefit from an efficient data structure for representing a large number of acoustic hypotheses compactly. Word graphs or lattices have been chosen as such an efficient interface between acoustic recognition engines and subsequent language processing modules. This paper first investigates the effect of pruning during acoustic decoding on the quality of word lattices and shows that by combining different pruning options (at the model level and word level), we can obtain word lattices with comparable accuracy to the original lattices and a manageable size. In order to use the word lattices as the input …
Diagnostics Of Eccentricities And Bar/End-Ring Connector Breakages In Polyphase Induction Motors Through A Combination Of Time-Series Data Mining And Time-Stepping Coupled Fe-State Space Techniques, John F. Bangura, Richard J. Povinelli, Nabeel Demerdash, Ronald H. Brown
Diagnostics Of Eccentricities And Bar/End-Ring Connector Breakages In Polyphase Induction Motors Through A Combination Of Time-Series Data Mining And Time-Stepping Coupled Fe-State Space Techniques, John F. Bangura, Richard J. Povinelli, Nabeel Demerdash, Ronald H. Brown
Electrical and Computer Engineering Faculty Research and Publications
This paper develops the foundations of a technique for detection and categorization of dynamic/static eccentricities and bar/end-ring connector breakages in squirrel-cage induction motors that is not based on the traditional Fourier transform frequency-domain spectral analysis concepts. Hence, this approach can distinguish between the "fault signatures" of each of the following faults: eccentricities, broken bars, and broken end-ring connectors in such induction motors. Furthermore, the techniques presented here can extensively and economically predict and characterize faults from the induction machine adjustable-speed drive design data without the need to have had actual fault data from field experience. This is done through the …
A New Temporal Pattern Identification Method For Characterization And Prediction Of Complex Time Series Events, Richard J. Povinelli, Xin Feng
A New Temporal Pattern Identification Method For Characterization And Prediction Of Complex Time Series Events, Richard J. Povinelli, Xin Feng
Electrical and Computer Engineering Faculty Research and Publications
A new method for analyzing time series data is introduced in this paper. Inspired by data mining, the new method employs time-delayed embedding and identifies temporal patterns in the resulting phase spaces. An optimization method is applied to search the phase spaces for optimal heterogeneous temporal pattern clusters that reveal hidden temporal patterns, which are characteristic and predictive of time series events. The fundamental concepts and framework of the method are explained in detail. The method is then applied to the characterization and prediction, with a high degree of accuracy, of the release of metal droplets from a welder. The …
Breakdown Probabilities For Thin Heterostructure Avalanche Photodiodes, Majeed M. Hayat, Ünal Sako ̆Glu, Oh-Hyun Kwon, Shuling Wang, Joe C. Campbell, Bahaa E.A. Saleh, Malvin Carl Teich
Breakdown Probabilities For Thin Heterostructure Avalanche Photodiodes, Majeed M. Hayat, Ünal Sako ̆Glu, Oh-Hyun Kwon, Shuling Wang, Joe C. Campbell, Bahaa E.A. Saleh, Malvin Carl Teich
Electrical and Computer Engineering Faculty Research and Publications
The recurrence theory for the breakdown probability in avalanche photodiodes (APDs) is generalized to heterostructure APDs that may have multiple multiplication layers. The generalization addresses layer-boundary effects such as the initial energy of injected carriers as well as the layer-dependent profile of the dead space in the multiplication region. Reducing the width of the multiplication layer serves to both downshift and sharpen the breakdown probability curve as a function of the applied reverse-bias voltage. In structures where the injected carriers have an initial energy that is comparable to the ionization threshold energy, the transition from linear mode to Geiger-mode is …
Scene-Based Nonuniformity Correction For Focal Plane Arrays By The Method Of The Inverse Covariance Form, Sergio N. Torres, Jorge E. Pezoa, Majeed M. Hayat
Scene-Based Nonuniformity Correction For Focal Plane Arrays By The Method Of The Inverse Covariance Form, Sergio N. Torres, Jorge E. Pezoa, Majeed M. Hayat
Electrical and Computer Engineering Faculty Research and Publications
What is to our knowledge a new scene-based algorithm for nonuniformity correction in infrared focal-plane array sensors has been developed. The technique is based on the inverse covariance form of the Kalman filter (KF), which has been reported previously and used in estimating the gain and bias of each detector in the array from scene data. The gain and the bias of each detector in the focal-plane array are assumed constant within a given sequence of frames, corresponding to a certain time and operational conditions, but they are allowed to randomly drift from one sequence to another following a discrete-time …
Optimal Excess Noise Reduction In Thin Heterojunction Al0.6Ga0.4As-Gaas Avalanche Photodiodes, Oh-Hyun Kwon, Majeed M. Hayat, Shuling Wang, Joe C. Campbell, Archie L. Holmes, Yi Pan, Bahaa E.A. Saleh, Malvin Carl Teich
Optimal Excess Noise Reduction In Thin Heterojunction Al0.6Ga0.4As-Gaas Avalanche Photodiodes, Oh-Hyun Kwon, Majeed M. Hayat, Shuling Wang, Joe C. Campbell, Archie L. Holmes, Yi Pan, Bahaa E.A. Saleh, Malvin Carl Teich
Electrical and Computer Engineering Faculty Research and Publications
It has been recently found that the initial-energy effect, which is associated with the finite initial energy of carriers entering the multiplication region of an avalanche photodiode (APD), can be tailored to reduce the excess noise well beyond the previously known limits for thin APDs. However, the control of the initial energy of injected carriers can be difficult in practice for an APD with a single multiplication layer. In this paper, the dead-space multiplication recurrence theory is used to show that the low noise characteristics associated with the initial-energy effect can be achieved by utilizing a two-layer multiplication region. As …
Scene-Based Nonuniformity Correction For Focal Plane Arrays By The Method Of The Inverse Covariance Form, Sergio N. Torres, Jorge E. Pezoa, Majeed M. Hayat
Scene-Based Nonuniformity Correction For Focal Plane Arrays By The Method Of The Inverse Covariance Form, Sergio N. Torres, Jorge E. Pezoa, Majeed M. Hayat
Electrical and Computer Engineering Faculty Research and Publications
What is to our knowledge a new scene-based algorithm for nonuniformity correction in infrared focal-plane array sensors has been developed. The technique is based on the inverse covariance form of the Kalman filter (KF), which has been reported previously and used in estimating the gain and bias of each detector in the array from scene data. The gain and the bias of each detector in the focal-plane array are assumed constant within a given sequence of frames, corresponding to a certain time and operational conditions, but they are allowed to randomly drift from one sequence to another following a discrete-time …