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Articles 1 - 30 of 38
Full-Text Articles in Engineering
Methods And Apparatus For Preventing A Third Party From Overhearing A Telephone Conversation, Thaddeus Gabara, Vladimir I. Prodanov
Methods And Apparatus For Preventing A Third Party From Overhearing A Telephone Conversation, Thaddeus Gabara, Vladimir I. Prodanov
Electrical Engineering
Methods and apparatus are provided for preventing a third party from listening to a conversation between at least two participants on a telephone. The telephone generates an audio stimulus signal that is presented through a secondary speaker. The audio stimulus signal may be, for example, pseudorandom noise or a cancellation signal. According to one aspect of the invention, the telephone ensures that the audio stimulus signal does not significantly impair the conversation for the at least two participants. To prevent the third party from listening to the local portion of the conversation, the audio stimulus signal is subtracted from the …
Automatic Generation Of Decomposition Based Matrix Inversion Architectures, Ali Irturk, Bridget Benson, Arash Arfaee, Ryan Kastner
Automatic Generation Of Decomposition Based Matrix Inversion Architectures, Ali Irturk, Bridget Benson, Arash Arfaee, Ryan Kastner
Electrical Engineering
Matrix inversion is an essential computation for various algorithms which are employed in multi-antenna wireless communication systems. FPGAs are ideal platforms for wireless communication; however, the need for vast amounts of customization throughout the design process of a matrix inversion core can overwhelm the designer. Decomposition methods provide the analytic simplicity and computational convenience necessary for computationally intensive matrix inversion. This paper presents automatic generation of different decomposition based matrix inversion architectures using a matrix inversion core generator tool, GUSTO with different parameterization options. We present automatic generation of a variety of general purpose matrix inversion architectures which have comparable …
A Small Scale Static Var Compensator For Laboratory Experiment, Taufik, Bryan Paet
A Small Scale Static Var Compensator For Laboratory Experiment, Taufik, Bryan Paet
Electrical Engineering
This paper presents a small scale static VAR compensator (SVC) circuit that could be used as either a laboratory demonstration or a laboratory experiment. The small scale SVC lab experiment effectively demonstrates SVCpsilas function in correcting power factor through the use of power thyristors in a phase-controlled circuit. The laboratory setup of the SVC circuit using a thyristor controlled reactor in parallel with a capacitor will discussed in this paper. Results from the lab setup to exhibit firing angle adjustment to inject or absorb VARs into the system will also be described.
Impact Of Multiple Adjustable Speed Drive System To Power System Harmonics, Taufik, Erin Matsumoto, Makbul Anwari
Impact Of Multiple Adjustable Speed Drive System To Power System Harmonics, Taufik, Erin Matsumoto, Makbul Anwari
Electrical Engineering
This paper presents harmonic analysis in a multiple adjustable speed drive system. In a system where multiple drives are fed from the same bus, harmonic currents produced by the various drives can reflect back to the power source and to the other drives causing distortion of the voltage waveform. If these harmonic currents are significant, they can potentially cause problems for the given system. Therefore studying the harmonics at various points in the system and comparing the values of total harmonic distortion can provide guidance in choosing appropriate filtering solutions. A two AC drive system was setup in a laboratory …
Load Sharing Characteristic Of Single Phase Pv Inverter Connected To Grid, M. Imram Hamid, Makbul Anwari, Z. Salam, Taufik
Load Sharing Characteristic Of Single Phase Pv Inverter Connected To Grid, M. Imram Hamid, Makbul Anwari, Z. Salam, Taufik
Electrical Engineering
This paper describes model and simulation of single phase PV inverters that work independently to supply three phase system as a part of renewable distributed generation. Load sharing characteristic of PV inverter and grid during supplying local load with current control method and relation of PV power level and current control performance to load sharing are simulated and analyzed. Furthermore, power quality behavior during connection/disconnection of PV plant, grid harmonics, voltage and current unbalance are simulated and analyzed. Model and simulation are implemented using MATLAB/Simulink.
Power Quality Behavior Of Single Phase Fed Adjustable Speed Drive Supplied From Grid Of Pv Generation, Makbul Anwari, M. Imran Hamid, Taufik
Power Quality Behavior Of Single Phase Fed Adjustable Speed Drive Supplied From Grid Of Pv Generation, Makbul Anwari, M. Imran Hamid, Taufik
Electrical Engineering
Power quality behavior on connecting single phase fed adjustable speed drives to a grid which photovoltaic as the power generation is studied in this paper. A MATLAB/Simulink simulations are performed to investigate the existence of power quality parameter and the system problems that may be resulted from operation of this type of load. The results indicate a potential serious power quality problem with the connected adjustable speed drives, which requires consideration during operation of PV generation which a number of this dynamic load.
Analysis And Design Of Interleaving Multiphase Dc-To-Dc Converter With Input Lc Filter, Kevin Thomas Delrosso
Analysis And Design Of Interleaving Multiphase Dc-To-Dc Converter With Input Lc Filter, Kevin Thomas Delrosso
Master's Theses
The future of microprocessors is unknown. Over the past 40 years, their historical trend has been for adopting smaller and more powerful designs that drive the world that we live in today. The state of the microprocessor business today faces a crossroad, wishing to continue on the historical trend of doubling the number of transistors on a chip every 18 months (Moore’s Law) but also facing the realistic task of needing to power these sophisticated devices. With the low voltages and high currents that are required for these microprocessors to operate, it poses a difficult task for the future designers …
High Speed Wavelength Tuning Of Sgdbr Lasers For Optical Coherence Tomography Applications, Benjamin Maher
High Speed Wavelength Tuning Of Sgdbr Lasers For Optical Coherence Tomography Applications, Benjamin Maher
Master's Theses
The application of Sample Grated Distributed Bragg Reflector (SGDBR) wavelength tunable lasers for swept-wavelength Optical Coherence Tomography (OCT) is explored. OCT is a method of measuring reflectivity versus distance into samples under test with a focused infrared light source. Swept wavelength OCT requires a laser light source that is capable of sweeping its wavelength quickly over the entire wavelength range of the tunable laser. Fast sweeping of the laser's wavelength enables real-time imaging of a wide surface area of the surface under test. This thesis will show that SGDBR lasers can be designed to meet the fast wavelength ramp speeds …
Fpga Acceleration Of Mean Variance Framework For Optimal Asset Allocation, Ali Irturk, Bridget Benson, Nikolay Laptev, Ryan Kastner
Fpga Acceleration Of Mean Variance Framework For Optimal Asset Allocation, Ali Irturk, Bridget Benson, Nikolay Laptev, Ryan Kastner
Electrical Engineering
Asset classes respond differently to shifts in financial markets, thus an investor can minimize the risk of loss and maximize return of his portfolio by diversification of assets. Increasing the number of diversified assets in a financial portfolio significantly improves the optimal allocation of different assets giving better investment opportunities. However, a large number of assets require a significant amount of computation that only high performance computing can currently provide. Because of the highly parallel nature of Markowitzpsila mean variance framework (the most popular approximation approach for optimal asset allocation) an FPGA implementation of the framework can also provide the …
Generation Of High Speed, Linear Wavelength Sweeps Using Sampled Grating Distributed Bragg Reflector Lasers, Shane O' Connor, Michael A. Bernacil, Dennis Derickson
Generation Of High Speed, Linear Wavelength Sweeps Using Sampled Grating Distributed Bragg Reflector Lasers, Shane O' Connor, Michael A. Bernacil, Dennis Derickson
Electrical Engineering
Wavelength-tunable sampled grating distributed Bragg reflector (SG-DBR) lasers are used for telecommunications applications in which the laser is set to a communication channel and changed infrequently. SG-DBR lasers can be tuned to any wavelength over a 50 nm tuning range with fast transition times using a set of three control currents. This paper demonstrates generation of fast linear wavelength ramps covering the entire tuning range of the laser. Continuous and linear wavelength sweeps are achieved by applying three time synchronized waveforms to the front mirror, back mirror, and phase sections of the laser. Continuous wavelength coverage is achieved by appending …
Optimization Of Top Polymer Gratings To Improve Gan Leds Light Transmission, Xiaomin Jin, Bei Zhang, Tao Dai, Wei Wei, Xiangning Kang, Guoyi Zhang, Simeon Trieu, Fei Wang
Optimization Of Top Polymer Gratings To Improve Gan Leds Light Transmission, Xiaomin Jin, Bei Zhang, Tao Dai, Wei Wei, Xiangning Kang, Guoyi Zhang, Simeon Trieu, Fei Wang
Electrical Engineering
We present a grating model of two-dimensional (2D) rigorous coupled wave analysis (RCWA) to study top diffraction gratings on light-emitting diodes (LEDs). We compare the integrated-transmission of the non-grating, rectangular-grating, and triangular-grating cases for the same grating period of 6 μm, and show that the triangular grating has the best performance. For the triangular grating with 6-μm period, the LED achieves the highest light transmission at 6-μm grating bottom width and 2.9-μm grating depth. Compared with the non-grating case, the optimized light transmission improvement is about 74.6%. The simulation agrees with the experimental data of the thin polymer grating encapsulated …
Design And Implementation Of Mobile Free Space Optical Communication System, Xiaomin Jin, Xian Wang, Chi Yeh Hsu
Design And Implementation Of Mobile Free Space Optical Communication System, Xiaomin Jin, Xian Wang, Chi Yeh Hsu
Electrical Engineering
No abstract provided.
A Pressure Sensing System Using Fiber Optic Sensors And Artificial Neural Networks, Xiaomin Jin, Xiao-Hua Yu, Saied Zarger, Roshan H. Patel, Sam Wards
A Pressure Sensing System Using Fiber Optic Sensors And Artificial Neural Networks, Xiaomin Jin, Xiao-Hua Yu, Saied Zarger, Roshan H. Patel, Sam Wards
Electrical Engineering
No abstract provided.
Survey Of Hardware Platforms For An Energy Efficient Implementation Of Matching Pursuits Algorithm For Shallow Water Networks, Bridget Benson, Ali Irturk, Junguk Cho, Ryan Kastner
Survey Of Hardware Platforms For An Energy Efficient Implementation Of Matching Pursuits Algorithm For Shallow Water Networks, Bridget Benson, Ali Irturk, Junguk Cho, Ryan Kastner
Electrical Engineering
Coral reefs worldwide are in serious decline. Underwater wireless sensor networks may be the answer to providing the persistent monitoring presence needed to obtain the data necessary to better understand how to protect these ecosystems for the future. Many advances have been made in underwater acoustic communication devices for underwater wireless sensor networks, but a major challenge that still remains is obtaining an energy efficient modem design. To begin to address this challenge, we implement the Matching Pursuits algorithm for channel estimation, an energy consuming portion of an existing underwater acoustic modem designed for shallow water networks, on a variety …
Neural Network Dimension Selection For Dynamical System Identification, Devin Sabo, Xiao-Hua Yu
Neural Network Dimension Selection For Dynamical System Identification, Devin Sabo, Xiao-Hua Yu
Electrical Engineering
Choosing an appropriate size of a network is an important issue for any neural network applications. The common practice is to start with an “over-sized” network, then gradually reduces its size to find the optimal solution. In this paper, a new hybrid neural network pruning algorithm for multi-layer feedforward neural networks is investigated. Computer simulation results on system identification and pattern classification problems show this algorithm can significantly reduce the network dimension while still maintaining satisfactory identification and classification accuracy.
Analysis And Design Of Multiphase Multi-Interleave Dc-Dc Converter With Input-Output Bypass Capacitor, Furqan Mubashir Saleemi
Analysis And Design Of Multiphase Multi-Interleave Dc-Dc Converter With Input-Output Bypass Capacitor, Furqan Mubashir Saleemi
Master's Theses
The power requirements for the microprocessor have been increasing as per Moore's Law. According to International Technology Roadmap (ITRS), the Voltage Regulator Module (VRM) for the microprocessor will be 200 W(with 1V, 200A output) in 2010. With the VRMs topology of synchronous buck, serious technical challenges such as small duty cycle, high switching frequencies, and higher current demands, contribute to decreased power density and increased cost. This thesis proposes a Multiphase Multi-Interleave Buck topology to solve the technical challenges of powering future microprocessors. The critical design parameter values are selected using the theoretical design equations and calculations. The design is …
Face And Lip Localization In Unconstrained Imagery, Brandon Crow, Jane Zhang
Face And Lip Localization In Unconstrained Imagery, Brandon Crow, Jane Zhang
Electrical Engineering
When combined with acoustical speech information, visual speech information (lip movement) significantly improves Automatic Speech Recognition (ASR) in acoustically noisy environments. Previous research has demonstrated that visual modality is a viable tool for identifying speech. However, the visual information has yet to become utilized in mainstream ASR systems due to the difficulty in accurately tracking lips in real-world conditions. This paper presents our current progress in addressing this issue. We derive several algorithms based on a modified HSI color space to successfully locate the face, eyes, and lips. These algorithms are then tested over imagery collected in visually challenging environments.
Optimize Neural Network Controller Design Using Genetic Algorithm, Ariel Kopel, Xiao-Hua Yu
Optimize Neural Network Controller Design Using Genetic Algorithm, Ariel Kopel, Xiao-Hua Yu
Electrical Engineering
The size of a neural network must be predetermined before it can be trained for any application. Choosing the correct size of a neural network can increase its speed of response and thus improve the performance of the overall system. In this paper, a genetic algorithm is employed to find the optimal number of connections of a neural network controller which is used to regulate a class of DC power supplies. Satisfactory computer simulation results are obtained.
Improvement Of Light Transmission Using Photonic Lattices For Solar Cells, Xiaomin Jin, Simeon Trieu
Improvement Of Light Transmission Using Photonic Lattices For Solar Cells, Xiaomin Jin, Simeon Trieu
Electrical Engineering
We study solar-cell interface designs using photonic lattices. We simulate rectangular and triangular micro-profiles as the solar cell surface. Compared to the conventional flat surface, the photonic lattice interface can increase light transmission to 98%.
Microwave Signal Generation Using Self-Heterodyning Of A Fast Wavelength Switching Sg-Dbr Laser, Michael A. Bernacil, Shame O' Connor, Ben Maher, Andew Dekelaita, Dennis J. Derickson
Microwave Signal Generation Using Self-Heterodyning Of A Fast Wavelength Switching Sg-Dbr Laser, Michael A. Bernacil, Shame O' Connor, Ben Maher, Andew Dekelaita, Dennis J. Derickson
Electrical Engineering
Microwave signal generation using self-heterodyning of a single wavelength tunable SG-DBR laser is demonstrated. Microwave signals are established by quickly hopping back and forth between two optical wavelengths. These wavelengths are made time coincident through a delay line interferometer. The output of the interferometer is photodetected resulting in a CW microwave signal. This method does not require conventional master-slave laser configurations, external microwave drive sources, or a mode locked laser used to beat dual longitudinal modes. Microwave signals up to 12 GHz have been measured by frequency modulating the phase section of the SG-DBR laser with low frequency RF square …
An Fpga Design Space Exploration Tool For Matrix Inversion Architectures, A. Irturk, B. Benson, S. Mirzaei, R. Kastner
An Fpga Design Space Exploration Tool For Matrix Inversion Architectures, A. Irturk, B. Benson, S. Mirzaei, R. Kastner
Electrical Engineering
Matrix inversion is a common function found in many algorithms used in wireless communication systems. As FPGAs become an increasingly attractive platform for wireless communication, it is important to understand the tradeoffs in designing a matrix inversion core on an FPGA. This paper describes a matrix inversion core generator tool, GUSTO, that we developed to ease the design space exploration across different matrix inversion architectures. GUSTO is the first tool of its kind to provide automatic generation of a variety of general purpose matrix inversion architectures with different parameterization options. GUSTO also provides an optimized application specific architecture with an …
A New Pruning Algorithm For Neural Network Dimension Analysis, Devin Sabo, Xiao-Hua Yu
A New Pruning Algorithm For Neural Network Dimension Analysis, Devin Sabo, Xiao-Hua Yu
Electrical Engineering
The choice of network dimension is a fundamental issue in neural network applications. An optimal neural network topology not only reduces the computational complexity, but also improves its generalization capacity. In this research, a new pruning algorithm based on cross validation and sensitivity analysis is developed and compared with three existing pruning algorithms on various pattern classification problems. Computer simulation results show the network size can be significantly reduced using this new algorithm while the neural network still maintains satisfactory generalization accuracy.
Theory, Simulation, Fabrication And Testing Of Double Negative And Epsilon Near Zero Metamaterials For Microwave Applications, Neil Patel
Master's Theses
Natural structures exhibiting simultaneous negative bulk permittivity and permeability have not yet been discovered. However, research interest over the past five years has grown with the proposition that artificial structures exhibiting these properties are realizable using specially-designed metallic inclusions embedded in host dielectric bodies. A periodic structure of metallic inclusions much smaller than the guided wavelength and embedded in a host dielectric medium is known in the physics and microwave communities as a "metamaterial". Such frequency-dependent effectively homogeneous materials may be designed to exhibit negative permeability and permittivity at certain frequencies. As predicted by electromagnetic theory, such negative index or …
Modeling And Simulation Of Paralleled Series-Loaded-Resonant Converter, Alejandro Polleri, Taufik, Makbul Anwari
Modeling And Simulation Of Paralleled Series-Loaded-Resonant Converter, Alejandro Polleri, Taufik, Makbul Anwari
Electrical Engineering
This paper presents the development of a circuit modeling for paralleled Series Loaded Resonant (SLR) converter used in an experimental power supply to drive high voltage and high frequency medical equipment. The circuit model for each individual converter is first described. Once the complete model of an individual converter is achieved, the model is then extended to include the parallel connection. To verify the validity of model, the design of paralleled SLR using the model is explained. The component values obtained are then being used in Pspice simulations to further prove the validity of the model.
Modeling And Simulation Of 6-Pulse And 12-Pulse Rectifiers Under Balanced And Unbalanced Conditions With Impacts To Input Current Harmonics, Arief Hernandi, Taufik, Makbul Anwari
Modeling And Simulation Of 6-Pulse And 12-Pulse Rectifiers Under Balanced And Unbalanced Conditions With Impacts To Input Current Harmonics, Arief Hernandi, Taufik, Makbul Anwari
Electrical Engineering
This paper discusses the impact of using 6-pulse and 12-pulse rectifier circuit commonly found in Adjustable Speed Drives. The 12-pulse topology is known to be more expensive, but produce the least input current harmonics. However, the latter statement is completely true under balanced line conditions. In practice, the lines are inherently unbalanced. Hence, the question of whether the 12-pulse rectifier will indeed perform better in terms of the harmonics injected to the line is still under on-going discussions. This paper presents the modeling and simulation of both rectifier topologies to compare their input current harmonics. The rectifiers are modeled using …
Modeling And Simulation Of Current Ripple In Dc Link Connecting Two Pwm Inverters Using Matlab/Simulink, Taufik, Makbul Anwari
Modeling And Simulation Of Current Ripple In Dc Link Connecting Two Pwm Inverters Using Matlab/Simulink, Taufik, Makbul Anwari
Electrical Engineering
In this paper, the impacts of PWM carrier signals to DC bus current ripple in a PWM-based generator-load system will be investigated. The study is crucial to aid in the determination of the dc bus capacitor in a real-world inverter system. A Simulink model depicting the contribution of the generator current and the load current to the total DC bus current will be described. Results of the computer simulations will also be discussed.
Credit-Based Dynamic Reliability Management Using Online Wearout Detection, John Y. Oliver, Rajeevan Amirtharajah, Venkatesh Akella, Frederic T. Chong
Credit-Based Dynamic Reliability Management Using Online Wearout Detection, John Y. Oliver, Rajeevan Amirtharajah, Venkatesh Akella, Frederic T. Chong
Electrical Engineering
As circuit geometries continue to shrink, and supply voltages remain relatively constant, circuit wearout becomes a concern. We propose that the relative reliability of the circuits of a processor be exposed to the operating system, and be managed by a credit-based wearout monitor. This wearout monitor receives dynamic updates of the reliability of circuits through the use of stability detector circuits that are small enough to be widely deployed. We find that through the combined use of the wearout monitor and stability detectors, we can efficiently and accurately manage the reliability of a processor, and re-coup the performance of a …
Power Quality Measurements Of A Dc Motor Drive, Nikil Mulakken, Taufik, Makbul Anwari
Power Quality Measurements Of A Dc Motor Drive, Nikil Mulakken, Taufik, Makbul Anwari
Electrical Engineering
This paper presents the results of power quality measurements performed on a DC motor drive. The power quality measurements involve a laboratory setup to investigate how various loading conditions on DC drive affect the efficiency, input power factor and total harmonic distortion of output armature current of a DC drive. Through the capture of this information, ways to minimize losses associated with the DC motor drive could be achieved based on finding an optimal operating point or region.
Effects Of Transverse Mode Coupling And Optical Confinement Factor On Gallium-Nitride Based Laser Diode, Xiaomin Jin, Zhang Bei, Dai Tao, Zhang Guo-Yi
Effects Of Transverse Mode Coupling And Optical Confinement Factor On Gallium-Nitride Based Laser Diode, Xiaomin Jin, Zhang Bei, Dai Tao, Zhang Guo-Yi
Electrical Engineering
We have investigated the transverse mode pattern and the optical field confinement factor of gallium nitride(GaN) laser diodes (LDs) theoretically. For the particular LD structure, composed of approximate 4 μm thick n-GaN substrate layer, the maximum optical confinement factor was found to be corresponding to the 5th order transverse mode, the so-called lasing mode. Moreover, the value of the maximum confinement factor varies periodically when increasing the n-sideGaN layer thickness, which simultaneously changes and increases the oscillation mode order of the GaN LD caused by the effects of mode coupling. The effects of the thickness and the average composition of …
Electric Motor Efficiency Under Variable Frequencies And Loads, Charles M. Burt, Xianshu Piao, Franklin Gaudi, Bryan Busch, Taufik
Electric Motor Efficiency Under Variable Frequencies And Loads, Charles M. Burt, Xianshu Piao, Franklin Gaudi, Bryan Busch, Taufik
Electrical Engineering
This paper details a study performed by the Irrigation Training and Research Center to determine motor performances under varying speeds [induced by a variable frequency drives (VFD) controller]and loads. A further goal of the study was to provide sufficient information to designers so that they could estimate total pumping plant power usage with a VFD-controlled installation. Motors were tested with a VFD as well as across-the-line. On average, the relative efficiency of the electrical system with a VFD may be approximately 8% lower than the relative efficiency of a properly designed, full-load across-the-line system. If one considers actual field operating …