Electrical and Computer Engineering Commons^™

Output Current Ripple Factor Performance Of Half-Wave Rectifier With And Without Freewheeling Diode, Taufik, Ali O. Shaban, Ahmad Nafisi

Electrical Engineering

The objective of this work is to investigate the ripple factor of half-wave rectifier circuits. The ripple factor is one of the important characteristics necessary when designing a power electronic converter. The ripple factor measures how much deviation the converter output parameter has, such as the output current, from its nominal designed value. In this paper the ripple factor of the output current of half-wave rectifiers is investigated. More specifically, the ripple factor of output current from more practical half-wave rectifiers that include inductive load with or without a freewheeling diode are analyzed and then compared to that of the …

Lip Feature Extraction Towards An Automatic Speechreading System, Xiaozheng Zhang, Russell M. Mersereau

Electrical Engineering

The use of color information can significantly improve efficiency and robustness of lip feature extraction capability over purely grayscale-based methods. Edge information provides another useful tool in characterizing lip boundaries. In this paper we present a method of integrating both types of information to address the problem of lip feature extraction for the purpose of speechreading. We first examine various color models and view hue as an effective descriptor to characterize the lips due to its invariance to luminance and human skin color, and its discriminative properties. We use prominent red hue as an indicator to locate the position of …

Relative Intensity Noise Characteristics Of Injection-Locked Semiconductor Lasers, Xiaomin Jin, Shun-Lien Chuang

Electrical Engineering

An experimental and theoretical study of relative intensity noise (RIN) spectra of side-mode injection-locked Fabry–Perot semiconductor lasers is reported. It is shown that the injection-locking technique effectively increases the relaxation oscillation frequency from 4.5 GHz (free-running mode) to 12 GHz (injection-locked mode) and enhances relaxation peaks of the slave laser RIN spectra. Results from our theoretical model, which include the key parameters for semiconductor quantum-well lasers, such as the linewidth enhancement factor, the nonlinear gain saturation coefficients, and optical confinement factor, show good agreement with our experimental results.

A Technique For Analyzing Radiation From Conformal Antennas Mounted On Arbitrarily-Shaped Conducting Bodies, Dean Arakaki, Douglas H. Werner, Raj Mittra

Electrical Engineering

This paper presents an efficient method to solve the problem of radiation from conformal aperture and microstrip antennas mounted on arbitrarily shaped conducting bodies. The method, based on the surface equivalence and reciprocity principles, uses a combination of the finite difference time domain (FDTD) and method of moments (MoM) techniques to substantially improve the computational efficiency of the radiation pattern calculation. When the geometry and location of the radiating element are modified, only a small portion of the overall analysis requires re-simulation. This leads to a significant improvement in computational efficiency over presently used techniques, and can substantially improve the …

A Method For Reducing The Variation In "On" Resistance Of A Mos Sampling Switch, A. K. Ong, Vladimir I. Prodanov, M. Tarsia

Electrical Engineering

Variation in the “on” resistance of a MOS sampling switch can introduce distortion into the front end of a switched-capacitor filter or analog-to-digital converter. We review three methods commonly used to linearize the resistance of a MOS switch and propose a new technique that addresses their limitations. A practical method for implementation is also suggested.

V-I Converters With Transconductance Proportional To Bias Current In Any Technology, Vladimir I. Prodanov

Electrical Engineering

In this paper we discuss circuits comprised of multiple differential pairs driven in parallel. We show that high linearity and linear with bias current tunability are intrinsic properties of any equidistant-offset multi-pair circuit. We argue that these two properties could potentially allow us to implement designs of analog filters, multipliers and other circuits that are (in first-order) technology independent. Simulations results are provided in support of presented simple intuitive explanation.

Steady State Operating Characteristics Of Hybrid Loaded Resonant Power Converter, Taufik

Electrical Engineering

No abstract provided.

Profiling The Performance Of Tcp/Ip On Windows Nt, P. Xie, M. Liu, J. Harris, C. Scheiman

Electrical Engineering

This paper presents detailed network performance measurements of a prototype implementation of the TCP/IP network software on Windows NT. The measurements include latency, throughput, and CPU utilization of the protocol stack and for some key operations within the stack

A Conformal Finite Difference Time Domain (Cfdtd) Algorithm For Modeling Perfectly Conducting Objects, Wenhua Yu, Raj Mittra, Dean Arakaki, Douglas H. Werner

Electrical Engineering

In this paper, the authors present a new and robust conformal Finite Difference Time Domain (FDTD) algorithm for the accurate modeling of perfectly conducting objects with curved surfaces and edges. We illustrate the application of this approach by analyzing a number of representative antenna and cavity problems. These include a quarter wave monopole mounted on a perfectly conducting elliptic disk, a circular patch antenna, and a cylindrical cavity. We validate the me~od by comparing the results for the pattern, impedance and resonant frequency, etc., with those derived by using other techniques.

A Technique For Analyzing Radiation From Conformal Antennas Mounted On Arbitrarily-Shaped Conducting Bodies, Dean Arakaki, Douglas H. Werner, Raj Mittra

Electrical Engineering

This paper presents an efficient method to solve the problem of radiation from conformal aperture and microstrip antennas mounted on arbitrarily-shaped conducting bodies. The method, based on the surface equivalence and reciprocity principles, uses a combination of the Finite Difference Time Domain (FDTD) and Method of Moments (MoM) techniques to substantially improve the computational efficiency of the radiation pattern calculation. When the geometry and location of the radiating element are modified, only a small portion of the overall analysis requires re-simulation. This leads to a significant improvement in computational efficiency over presently-used techniques, and can substantially improve design efficiency when …

Evaluation Of Infrared And Millimeter-Wave Imaging Technologies Applied To Traffic Management, C. Arthur Maccarley, Brian M. Hemme, Lawrence Klein

Electrical Engineering

This paper reviews the findings of a study commissioned by the California Department of Transportation to evaluate the potential of infrared and passive millimeter-wave imaging technologies for traffic surveillance and automated detection. Images formed from radiation at infrared and millimeter wavelengths are characterized by fundamentally different information compared with visible-spectrum images, and generally improved ability to penetrate obscured atmospheres such as fog or dust.

Ten examples of commercially available infrared (IR) imaging technologies and one experimental passive millimeter-wave (MMW) radiometric imaging apparatus were evaluated with respect to the specific requirements of highway monitoring and traffic management. A suite of traffic …

Electroluminescent Display Device Including Active Polymer Layer, Aemilianus G. J. Staring, David Braun, Karel E. Kuijk

Electrical Engineering

Control device for an electroluminescent display device, comprising an active layer of a semiconducting polymer of, for example pixels arranged in the form of a matrix, reducing flicker and crosstalk. The control device may be based on voltage control at which voltages across the pixels are at least 1.6 V, but is preferably based on current control, at which the duration of the data pulses determines the grey level.

A Review Of Battery Exchange Technology For Refueling Of Electric Vehicles, C. Arthur Maccarley

Electrical Engineering

The limited energy storage and long recharge time and of electric vehicle batteries have motivated several alternatives to in-vehicle slow charging. Solutions generally fall into three categories: (1) fast charging, in which batteries are charged in-vehicle at an accelerated rate, (2) battery material reloading or refueling, in which the energy-carrying elements of the battery are physically replaced or replenished, and (3) battery interchange, involving the complete exchange of the battery pack, usually with the aid of some semi-automated mechanism. Among these options, the last, battery interchange, has tended to receive the least industry attention, but has been an expansive topic …

Electroluminescent Device Comprising A Transparent Structured Electrode Layer Made From A Conductive Polymer, Aemilianus G. J. Staring, David Braun

Electrical Engineering

A description is given of an electroluminescent (EL) device (1) composed of polymeric LEDs comprising an active layer (7) of a conjugated polymer and a transparent polymeric electrode layer (5) having electroconductive areas (51) as electrodes. Like the active layer (7), the electrode layer (5) can be manufactured in a simple manner by spin coating. The electrode layer (5) is structured into conductive electrodes (51) by exposure to UV light. The electrodes (9) and (51) jointly form a matrix of LEDs for a display. When a flexible substrate (3) is used, a very bendable EL device is obtained.

Parallel Ac-Ac Converters Using Stationary Master Slave Control, Taufik, F. E. Villaseca

Electrical Engineering

This study proposes parallel ac-ac converters using Stationary Master Slave Control with Sinusoidal Pulse Width Modulation to achieve voltage regulation and equal current sharing among parallel generators such that it minimizes the total production cost. Development of Pspice model representing the parallel ac-ac converters is presented and then simulated. In addition, computer simulations are also used to perform robustness study on the parallel converters.

Temperature Dependence Of Electrical And Optical Modulation Responses Of Quantum-Well Lasers, T. Keating, Xiaomin Jin, Shun Lien Chuang, K. Hess

Electrical Engineering

We present theory and experiment for high-speed optical injection in the absorption region of a quantum-well laser and compare the results with those of electrical injection including the carrier transport effect. We show that the main difference between the two responses is the low-frequency roll-off. By using both injection methods, we obtain more accurate and consistent measurements of many important dynamic laser parameters, including the differential gain, carrier lifetime, K factor, and gain compression factor. Temperature-dependent data of the test laser are presented which show that the most dominant effect is the linear degradation of differential gain and injection efficiency …

Optical Gain Measurements Based On Fundamental Properties And Comparison With Many-Body Theory, T. Keating, S. H. Park, J. Minch, Xiaomin Jin, Shun-Lien Chuang, T. Tanbun-Ek

Electrical Engineering

We present high accuracy measurements of gain, loss, and transparency energy in long-wavelength semiconductors based on a hybrid approach using the fundamental relationship between the gain and the spontaneous emission spectra. Independent measurements of optical gain, transparency energy, and loss show the accuracy and validity of this technique. These results are compared with those obtained by the non-Markovian gain model with many-body effects under the spontaneous emission transformation method. It is found that the hybrid approach for the gain spectrum alleviates many of the problems related to the poor signal to noise ratio in the amplified-spontaneous emission near and below …

Evaluation Of Caltrans District 10 Automated Warning System, Year Two Progress Report, Art Maccarley

Electrical Engineering

District 10 of the California Department of Transportation (Caltrans) encompasses an area of seasonal fog and dust-related visibility problems that have been the cause of numerous multi-car traffic collisions, many fatal. In 1990, motivated by the expansion of State Route 120 (SR 120) connecting Interstate Highway 5 (I-5) and State Route 99 (SR 99), Caltrans proposed a sophisticated multi-sensor automated warning system as a means for reducing incidents in this high-traffic area. This proposal, and the significant development effort that followed, culminated in the implementation of Phase 1 of the Caltrans Automated Warning System, or “CAWS”, which entered service in …

An Efficient Finite Difference Time Domain (Fdtd) Technique For Modeling A Reflector Antenna System With Partial Circular Symmetry, Dean Arakaki, Wenhua Yu, Raj Mittra

Electrical Engineering

This paper presents an efficient method for solving a large body scattering problem, viz., a paraboloidal reflector antenna system with only partial circular symmetry. The asymmetry in the system is introduced by two factors, viz., the microstrip feed and an inhomogeneous radome. The paper presents a novel approach, based on the reciprocity principle and the “equivalent aperture” theory, to handle the asymmetry problem and still take advantage of the circular symmetry of the large paraboloid of revolution to render the problem manageable

Electroluminescent Illumination System, Dirk J. Broer, David Braun, Antonius H.J. Venhuizen, Christianne R.M. De Witz

Electrical Engineering

An illumination system has an active layer which includes an electroluminescent material, the active layer being located between an optically transparent electrode layer and a reflective electrode layer. A reflective polarizer is present at a side of the transparent electrode layer facing away from the active layer. A sub-beam incident on the polarizer and having an unwanted polarization is reflected back to the active layer, where it is again partially depolarized to recover a component having the desired state of polarization. The invention also relates to a flat-panel picture display device which includes such an illumination system.

Crosstalk And Image Uniformity In Passive Matrix Polymer Led Displays, David Braun, J. Rowe, G. Yu

Electrical Engineering

Passive matrix displays based on polymer and organic light-emitting diodes suffer from crosstalk, when the emission of light from one pixel depends on the operation of another pixel. We use circuit simulation in order to explain the causes of crosstalk and to quantify the consequences. This work analyzes how crosstalk arises from electrode resistance, pixel leakage current, and the location of faulty pixels. All factors influence both image uniformity and the power consumption of the display.

Simulations Of Passive Matrix Polymer Image Sensors, David Braun, G. Yu

Electrical Engineering

Two-dimensional passive photodiode matrices are hardly useful for image sensing due to the crosstalk between pixels. This crosstalk makes it difficult to recover information from individual pixels. A switching unit attached to each sensing unit has been the common solution in image sensors (such as in CMOS sensors and in TFT-PiN a-Si photosensors). A novel organic photodiode with voltage-switchable photosensitivity was developed recently. Passive photodiode matrices made with such organic photodiodes can be used for image sensing applications. This circuit simulation study demonstrates an effective scheme to extract images from passive photodiode matrices, concluding that individual photodiode parameters determine the …

Fabrication Of Visible Light Emitting Diodes Soluble Semiconducting Polymers, Alan J. Heeger, David Braun

Electrical Engineering

Visible light LEDs are produced having a layer of conjugated polymer which is cast directly from solution or formed as a gel-processed admixture with a carrier polymer. The LEDs can be formed so as to emit polarized light.

Long-Term Memory Motion-Compensated Prediction, Thomas Wiegand, Xiaozheng Zhang, Bernd Girod

Electrical Engineering

Long-term memory motion-compensated prediction extends the spatial displacement vector utilized in block-based hybrid video coding by a variable time delay permitting the use of more frames than the previously decoded one for motion compensated prediction. The long-term memory covers several seconds of decoded frames at the encoder and decoder. The use of multiple frames for motion compensation in most cases provides significantly improved prediction gain. The variable time delay has to be transmitted as side information requiring an additional bit rate which may be prohibitive when the size of the long-term memory becomes too large. Therefore, we control the bit …

New Cmos Universal Constant-Gm Input Stage, Vladimir I. Prodanov, Michael M. Green

Electrical Engineering

Conceptually new constant-Gm input-stage architecture is presented. It provides near constant net transconductance independent of transistor operating region-strong, moderate or weak inversion. One possible implementation of the proposed architecture is discussed in details. Its operation has been experimentally verified. Results from performed measurements are included.

A Neural Network Pruning Algorithm With Embedded Gradient-Conjugate Training For The Identification Of Large Flexible Space Structures, Xiao-Hua Yu

Electrical Engineering

The choice of network dimension is a fundamental issue in the design of artificial neural networks. A larger neural network is powerful for solving problems while a smaller neural network is always advantageous in real-time environment where speed is crucial. In this paper, a network pruning algorithm with embedded gradient-conjugate training is investigated and applied to the identification of a large flexible space structure. Computer simulation results show that this approach can dramatically reduce the size of neural network while maintaining compatible identification accuracy.

Signal Monitoring Apparatus For Wavelength Divison Multiplexed Optical Telecommunication Networks, Dennis J. Derickson, Roger Lee Jungerman

Electrical Engineering

A detector array spectrometer simultaneously monitors wavelength, power, and signal-to-noise ratio of wavelength division multiplexed (WDM) channels in telecommunication networks. A spectrometer spatially separates signals from the WDM channels according to the channels' wavelengths. The separated signals are incident on an array of split-detectors that conforms to the spatial separation of the signals provided by the spectrometer. While the split-detectors are positioned to receive a signal from each WDM channel, a noise detector is positioned between adjacent split-detectors to measure noise. A common mode output from two halves of each split-detector indicates the power in a WDM channel, while a …

Optimization Of Network Signal Timing, Xiao-Hua Yu, Allen R. Stubberud

Electrical Engineering

A typical urban traffic network is a complicated large-scale stochastic system which consists of many interconnected signalized traffic intersections. This paper develops a decentralized real-time adaptive control strategy for the traffic networks based on Markov decision theory. Computer simulation results of this new approach on a five intersection traffic network indicate significant improvement over the traditional fully actuated control algorithm.

Electroluminescent Device Having Electroluminescent Compound And Liquid Crystalline Compound, Rifat A.M. Hikmet, David Braun, Aemilianus G.J. Staring, Hermanmus F.M. Schoo, Johan Lub

Electrical Engineering

A description is given of an electroluminescent device (1) having an LED structure, which is composed of an active layer (7) of oriented liquid-crystalline and electroluminescent compounds and a transparent positive electrode layer (5) which is preferably made from an electroconductive polymer. By previously rubbing the electrode layer (5) in one direction with a velvet cloth, an orientation is induced in the molecules in the active layer (7), the orientation being frozen by cooling or polymerization. The electroluminescent device (1) emits polarized light whose direction of polarization is parallel to the direction of rubbing.

Final Report: City Of Anaheim/Caltrans/Fhwa Advanced Traffic Control System Field Operational Test Evaluation Task C, Video Traffic Detection System, Art Maccarley, Cal Poly Transportation Electronics Laboratory

Electrical Engineering

A technical evaluation was conducted as a subtask of the “City of Anaheim Advanced Traffic Control System Field Operational Test (FOT)”, funded by the US DOT / FHWA and the California Department of Transportation. Partners for this FOT are the City of Anaheim, Odetics Inc. of Anaheim, JHK Consulting, and the California Department of Transportation. This report is the result of evaluation Task C “VTDS Evaluation”, one of three evaluation tasks covering components of the FOT. The component evaluated under Task C is a video-based vehicle detection system for actuation of traffic signals at intersections. This system, referred to as …