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Full-Text Articles in Electrical and Electronics

A Machine Vision System With Remote Host, Chieyeon Jason Chen Jan 1991

A Machine Vision System With Remote Host, Chieyeon Jason Chen

Theses

The modem plays an important role in data communication using the Public Swiched Telephone Network. In this thesis, the modem function is merged into a low cost machine vision system based on the Motorola 68HC11. Evalation Board The system comprises the intelligent machine vision con- troller and a remotely located host computer, such as an IBM-PC. It, supports extra long distance communication capability so that the controller and the host can be anywhere in the world where then is a telephone line. Because of the limit of a 2100 bps modem, soft ware data compression is implemented here to save …


Artificial Dielectric Polymeric Optical Waveguides, Peng Chen Jan 1991

Artificial Dielectric Polymeric Optical Waveguides, Peng Chen

Theses

Wave propagation in artificial dielectric polymeric optical thin film waveguides is studied. These artificial dielectric films are made of multiple layers either metallic or semiconductor clusters in polymeric matrix. The waveguides are fabricated using the plasma polymerization and vacuumm evaporation deposition method. By analyzing results of these kinds of structures, some important conclusions can be obtained. The artificial dielectric layer in the waveguide center effectively changes the modal distribution in the waveguides. In the case of semiconductor layer, an all optical switch may be realized.


A Multimode Index Detecting Sensor For Use In Plastic Concrete, Qiyu Chen Jan 1991

A Multimode Index Detecting Sensor For Use In Plastic Concrete, Qiyu Chen

Theses

This thesis describes a microcomputer-based measuring system using a laser diode source, a fiber optic sensor and a microcomputer DMA interface to test and analyze the entrained percentage of air in concrete.

The principle of refraction and reflection of light in optical fibers is applied to detection of air bubbles. Reflected light intensity signals are detected and transferred through a DMA interface to a laptop computer. Analysis of reflected light intensity produces a measurement of the air content of fresh concrete. Accuracy of the system is evaluated through extensive laboratory and field trials.


Ct Fan Beam Reconstruction With A Non-Stationary Axis-Of-Rotation, Joseph A. Concepcion Jan 1991

Ct Fan Beam Reconstruction With A Non-Stationary Axis-Of-Rotation, Joseph A. Concepcion

Theses

One important aspect for reconstructing an image using Computed Tomography (CT) is that the axis-of-rotation must pivot at the same point on the reconstruction plane as the x-ray source and CT scanner assembly rotates around the imaged object. This pivot point is used as a reference point for backprojecting pixel values to their proper coordinates. Therefore, reconstructing an image with a non-stationary axis-of-rotation would backproject pixel values to wrong coordinate points, since the reference point is non-stationary for every projection angle.

A convolution filtered backprojection algorithm has been derived for correcting images that were acquired with a non-stationary axis-of-rotation using …


Tri-Color Led Display System Using Microcontroller, Costakis A. Constantinou Jan 1991

Tri-Color Led Display System Using Microcontroller, Costakis A. Constantinou

Theses

A seven-by-forty-eight tricolor LED display panel is designed and built around the 68HC11 MCU.

Four bilateral switching transistors (4066) are used in a Wien bridge configuration to drive each tri-color LED. With this circuitry one is able to drive the tricolor LED symmetrically. An alternative design that uses only two switching transistors is also offered.

A software program was developed to output on the display scrolling and fixed messages. Each message could be displayed in a different color (Red, Green and Yellow) and at a different speed (Slow, Fast, and Medium). The program also includes an editor with insertion and …


Novel Way Of Sub-Carrier Coherent Detection And Clock Recovery In Fiber-Optic Communications, Narayan Gehlot Jan 1991

Novel Way Of Sub-Carrier Coherent Detection And Clock Recovery In Fiber-Optic Communications, Narayan Gehlot

Theses

We experimentally demonstrate a novel concept for recovery of a Sub-Carrier and Timing Clock in fiber-optic communication systems using a Wavelength Division Multiplexing technique. The idea is to send a low radio frequency (RF) as a reference pilot from the transmitter to the receiver on a separate laser using the principle of Wavelength Division Multiplexing (WDM). This low frequency signal is taken to be a subharmonic of the subcarrier used to carry information and intensity modulate another laser. Such approach will be expected to generate at the receiver a local oscillator in high coherence with the subcarrier.

We show that …


Uniformity Correction For Infrared Ir-Ccd Camera, Chien-Ming Leng Jan 1991

Uniformity Correction For Infrared Ir-Ccd Camera, Chien-Ming Leng

Theses

This thesis describes the results of a study of three types of uniformity correction schemes for an infrared camera. More specifically, a Datacube Image System was used to simulate the three uniformity correction schemes for a 320x244-element IR-CCD TV camera with PtSi Schottky-barrier detectors. The three uniformity correction schemes are: one-point uniformity correction with single background, one-point uniformity correction with multibackground and two-point uniformity correction. Datacube programs were developed for the three above uniformity correction schemes and some experimental results were obtained.


On The Estimation Of New Life Model Of Transformer Insulation Material Under Combined Electrical And Thermal Stress, Chiming Lin Jan 1991

On The Estimation Of New Life Model Of Transformer Insulation Material Under Combined Electrical And Thermal Stress, Chiming Lin

Theses

Results of combined electrical and thermal aging and only thermal aging studies conducted on a 'fish' paper insulation material are presented in this thesis.

The model for aging has been proposed which is essentially the Arrhenius equation with a weighted factor {exp -cg/kT1 to describe the enhanced reaction rate process under combined thermal and electrical stress. A procedure has been described for evaluation of parameters of this new model.

It is seen that life estimates obtained with this model are close enough to the experimental results.

In addition, reliability data were also generated on the same material using electrical noise. …


The Bandwidth Allocation Of Atm Through Genetic Algorithm, Hong Pan Jan 1991

The Bandwidth Allocation Of Atm Through Genetic Algorithm, Hong Pan

Theses

In this thesis, we develop an optimization method based on Genetic Algorithm to achieve the bandwidth allocation of ATM network. In Broadband Integrated Service Digital Network (BISDN), the Asynchronous Transfer Model (ATM) is already adopted as the transfer standard by CCITT. ATM is a high-bandwidth, low-delay, fast-packet switching and multiplexing technique. Using ATM technique, we can flexibly reconfigure the network and reassign the bandwidth to meet the requirement of all types of services. As an effective optimization method, Genetic Algorithm(GA) is applied to implement the bandwidth allocation of ATM. GA is a class of search algorithm based on the mechanics …


Dual Token Ring Lan Performance, Pratap S. Pasupuleti Jan 1991

Dual Token Ring Lan Performance, Pratap S. Pasupuleti

Theses

A simulation model to analyze the performance of a dual token ring LAN is developed. The performance measures throughput, average packet delay and maximum delay per packet are obtained. System performance is analyzed for different loads, number of stations, and packet lengths. The performances of token ring LANs with a conventional structure and a dual ring structure are compared for both uniform packet sizes and a case with mixed packet sizes. In the uniform packet size case, the dual ring delays were lower at equivalent throughput because of propagation delay effects. In the mixed packet size case the maximum delays …


Hot : A Timing Optimizer For Hierarchical Vlsi Circuits Using The Charge Conservation Delay Model, Yumei Quan Jan 1991

Hot : A Timing Optimizer For Hierarchical Vlsi Circuits Using The Charge Conservation Delay Model, Yumei Quan

Theses

The primary benefits of VLSI chips are their high speed, small area, and lower power. These performance attributes are dependent on the quality of chip design. As a result, performance can be optimized by proper design decisions. One of the decisions in chip design is the selection of gate delays and/or transistor sizes (channel width of an MOS transistor).

To optimize the performance of VLSI chips, transistor delay models and optimization algorithms are very important since accurate analytical models for signal delay are essential to replace expensive device level simulation and the high efficient algorithms assist designers in developing high …


Design, Fabrication, And Testing Of Temperature Compensated Magfet, Dilip K. Sampath Jan 1991

Design, Fabrication, And Testing Of Temperature Compensated Magfet, Dilip K. Sampath

Theses

A simple model based on dc behaviour of MOS transistors operating in weak inversion is derived on the basis of previous publications. The bipolar like source to drain transfer characteristics of MOS transistor in weak inversion was used to implement a voltage source that is proportional to absolute temperature (PTAT); a cell that can be stacked to obtain the desired voltage. A CMOS temperature compensated current reference is implemented using PTAT cell with MOSFET as current defining element. A CMOS magnetic field sensor has been developed. The sensitivity of sensor is dependant on the bias current; incorporation of temperature independent …


An Efficient Annealing Algorithm For Global Optimization In Boltzmann Machines, Rajendra Sarasakrishna Jan 1991

An Efficient Annealing Algorithm For Global Optimization In Boltzmann Machines, Rajendra Sarasakrishna

Theses

This thesis proposes a new annealing algorithm for Boltzmann Machines. This algorithm uses an Exponential Formula for temperature scheduling that produces remarkably better solutions for global optimization. The superiority of the new algorithm is shown by computer simulations of several examples on Boltzmann Machine and its variants. This is also shown to have better properties than algorithms like Generalized Simulated Annealing which possess somewhat similar dynamics.


Comparative Study Of Prediction Gain Based On Neural Network Architecture, Prashant M. Shah Jan 1991

Comparative Study Of Prediction Gain Based On Neural Network Architecture, Prashant M. Shah

Theses

This thesis describes the Neural Network approach to design predictor using Delta and Generalized Delta Rule. The predictor is designed by supervised training based on the typical sequence of pixel values. Neural Network is used to find the coefficients of the predictor. Both 1-D and 2-D scheme of the pixels as well as linear and non-linear correlations are used to find the coefficients by training. Different combinations of pixels are used to find the "best" combination among the order of the predictor.


Efficient Multiprocessor Scheduling By Mean Field Theory Neural Networks, Pei-Ken Yi Jan 1991

Efficient Multiprocessor Scheduling By Mean Field Theory Neural Networks, Pei-Ken Yi

Theses

In this thesis, we develop an optimization method based on Mean Field Theory (MFT) Neural Networks to solve the Task Scheduling problem. The MFT algorithm combines characteristics of the Simulated Annealing (SA) algorithm and the Hopfield neural network. MFT exhibits rapid convergence and at the same time it preserves the solution quality afforded by SA. Since MFT has been successfully used to solve the Traveling Salesman Problem (TSP), a new modification to MFT is also presented which supports Task Scheduling problem. The temperature behavior of MFT during Task Scheduling is approximately analyzed and shown to possess a critical temperature (71,) …


Integrated Digital Speech System With Pc, Zhen Zhu Jan 1991

Integrated Digital Speech System With Pc, Zhen Zhu

Theses

A PC-based real-time digital speech processing system is designed. Speech synthesis, analysis, storage and retrieval are implemented in the system with intelligent telephone functions. Speech data are stored on floppy disk and easy to retrieve. Though floppy disk is slow in speed, real-time processing is achieved with low bit rate coding. The computer gets speech data from a digital speech processing unit or send data to it through a synchronous seiial communication port. The analog input of digital speech processing unit can be selected from the telephone line or the microphone, and output of the digital speech processing unit can …


Decomposing Non-Product Form Queueing Lattices Through Autorouting With A* Algorithm, Chun-Chang Yu Jan 1991

Decomposing Non-Product Form Queueing Lattices Through Autorouting With A* Algorithm, Chun-Chang Yu

Theses

Direct solution techniques are expensive for the state transition lattice of a class of non-product form queuing modes. In this thesis, Autorouting with A* algorithm is adapted to decompose it as solvable subsets which can be solved sequentially and independently. Autorouting with A* algorithm is heuristics in problem solving. It also is one of a class of global optimization problems that are difficult to solve. Some queuing modes of type A will be decomposed in this thesis through Autorouting with A* algorithm.


N-Cross Coupled Phase Locked Loops, Joseph C. Aboukhalil Jan 1991

N-Cross Coupled Phase Locked Loops, Joseph C. Aboukhalil

Theses

Interference cancelation has been mainly performed using arrays, in an important issue in communication both array and spatial cancelation and time domain approach were used. In array applications, depth of cancelation may dependent on the interferences to background power ratio and their spatial distributions. Also, array cancelers are inadequate when the signals are less than an array beamwidth apart. The latter was dealt with using supperesolution and eigenanalysis methods. Different time domain methods were used in the past. Among them what is termed Cross-Coupled PEL. It is an arrangement of two PLL each one is locked on and tracking one …


Fault Tolerant Clos Network, Preet Mohan S. Ahluwalia Jan 1991

Fault Tolerant Clos Network, Preet Mohan S. Ahluwalia

Theses

Multistage interconnection networks, or MINs, provide paths between functional modules in multiprocessor systems. The MINs are usually segmented into several stages. Each stage connects inputs to appropriate links of the next stage so that the cumulative effect of all the stages satisfies input-output connection requirements.

This thesis deals with a fault tolerant Clos network. The fault tolerance technique involves addition of extra switches per stage to compensate for any switch failure The reliability analysis of both ordinary and fault tolerant Clos networks is presented. The optimal number of extra switches required to get the best reliability results has been analyzed.


Estimating 3-D Motion And Structure Parameters Of A Rigid Planar Object By Establishing Landmark Correspondences, Herman Agustiawan Dec 1990

Estimating 3-D Motion And Structure Parameters Of A Rigid Planar Object By Establishing Landmark Correspondences, Herman Agustiawan

Theses

The application of a landmark based approach in recognizing 3-D rigid planar objects[3] along with two different motion and structure estimation algorithm [21][23] have been studied to perform motion and structure estimation tasks of moving objects. The recognition algorithm is based on a sphericity value derived from affine transformation that maps feature points in the object under observation from first to second view in the 2-D image space. The motion and structure estimation algorithm is based on a unique mapping given four or more feature point correspondences.

More than ten experiments have been done including small and large rigid motions. …


A Transistor Delay Model Based On Charge Conservation, Bharatsingh K. Bisen Dec 1990

A Transistor Delay Model Based On Charge Conservation, Bharatsingh K. Bisen

Theses

Delay information of a circuit is often used in the areas of timing verification, timing analysis, race detection and circuit optimization. Given a circuit its delay can be estimated by various simulation techniques. SPICE is one of the simulation techniques, but it is seen that with the increase in the complexity of the circuit the SPICE circuit simulation technique to obtain delay information become cumbersome and computationally too expensive. So as to overcome the above disadvantages of the circuit simulation technique to obtain delay information various timing delay models were developed. However general survey of most of these timing delay …


Digital Correlators For Spread Spectrum Communications, Raymond B. Chadwick Dec 1990

Digital Correlators For Spread Spectrum Communications, Raymond B. Chadwick

Theses

The design and application, in spread spectrum communications, of a digital correlator implemented in a Xilinx Field Programmable Gate Array is presented. Spread spectrum communications, correlators and Xilinx Field Programmable Gate Arrays are first introduced. A digital correlator is designed and implemented in a Xilinx Field Programmable Gate Array. Cascading correlators to increase the correlation dimensions is next explored. The maximum operating frequency of the digital correlator is calculated and simulated to be 40 Mhz; a significant speed improvement over commercially available correlators such as those from TRW.


Recovering Surface Structure Using Direct Method, Zhu Ying Dec 1990

Recovering Surface Structure Using Direct Method, Zhu Ying

Theses

A new approach to recovering surface structure from a pair of stereo images is proposed in this thesis. The approach is based on an extension of the concept of optical flow to a spatial sequence of images. z.e., the unified optical field (DOFF). A direct method in spatial domain is developed which is able to recover surface structure that can be characterized by an Nth order polynomial equation. The order N of the surface can be one. a planar surface. or two, a cylindrical or spherical surface. for example. or any number higher than two. This is a big improvement …


An Investigation Of Optoelectronic Integrated Circuit Receiver, Dinar S. Gupte Dec 1990

An Investigation Of Optoelectronic Integrated Circuit Receiver, Dinar S. Gupte

Theses

This thesis report presents an investigation of an OptoElectronic Integrated receiver Circuit (OEIC). An OEIC on Silicon (Si) substrate is analyzed and simulated as part of this investigation. The OEIC is based on GaAs technology. The advantages of this are its compactness, high speed, low noise and high reliability in light wave communication systems. A higher output signal is required to make such devices suitable for practical applications. This is achieved by the use of a cascode stage. The fabrication techniques of the relevant semiconductor devices have also been discussed.

In light wave communication systems, the region of minimum losses …


Wideband Microstrip Antenna Optimization, Amer Muhammad Alsawadi Dec 1990

Wideband Microstrip Antenna Optimization, Amer Muhammad Alsawadi

Theses

An annular ring patch microstrip antenna was investigated numerically from the bandwidth aspect for a satellite link application. The desired portable antenna should occupy the physical volume of a typical briefcase and operate in the 400-500 MHz band. Numerical optimization is carried out using a commercially available computer package (EM, by Sonnet Software Inc.). The parameters optimized include the substrate thickness, feed location along the annular patch antenna and its relative dimensions. The software package was numerically validated for the rectangular patch geometries reported in the open literature. Experimental verification of this work is left to be carried out in …


Optimization On Isdn In Multihop Radio Networks Through Genetic Algorithm, Prashant H. Pahade Dec 1990

Optimization On Isdn In Multihop Radio Networks Through Genetic Algorithm, Prashant H. Pahade

Theses

Integrated service of voice and data on a single network has received considerable attention recently. Various techniques have been proposed and analysed for multiplexing voice and data over a large bandwidth channel. Efficient channel allocation for voice and data on multihop radio network is what we are most concerned about. In this paper, we address the problem of determining optimal access policies for a tandem ISDN network by using Genetic Algorithm. Computer Simulation shows that this leads to the decision which is beneficial to the services of both voice and data in the network.


Holographic Photo-Induced Electrochemical Etching Of Diffraction Grating In N-Inp, Pei-Chen Pien Dec 1990

Holographic Photo-Induced Electrochemical Etching Of Diffraction Grating In N-Inp, Pei-Chen Pien

Theses

Maskless laser-induced etching and plating is a novel technology for etching a three dimensional profile on semiconductor wafers. Using this technique, we may avoid the contaminating mask stage and achieve in-situ monitoring of the on-going process. In this thesis, we have presented findings on light diffraction from an etched pattern in a thin-film cell configuration. We suggest that the etched pattern develops mostly linearly in time with this arrangement, although indirect monitoring of the reaction process such as by light diffraction, should be carefully interpreted. In-situ light diffraction monitoring appear as if light was scattered from an etched pattern developed …


A Petri Net Simulation Tool, Ashish H. Shukla Dec 1990

A Petri Net Simulation Tool, Ashish H. Shukla

Theses

A user friendly and highly interactive graphical tool for drawing, editing and simulating translated Petri Net models is developed. This SunView based tool allows simulation to be carried out in the 'step' and 'run' modes. In the 'run' mode it produces a log file of the simulation run which consists of: a) total number of tokens in the net; b) names of the transitions that fired; and c) the system state reached after each step's execution. The tool offers a new solution to the problem of modeling concurrent and interlocked systems, such as computer systems, modular software, flexible manufacturing systems …


Electrical Measurements Of Mos Structures Fabricated On Etched Silicon Surfaces, Venkata Ramana Vankayalapati Dec 1990

Electrical Measurements Of Mos Structures Fabricated On Etched Silicon Surfaces, Venkata Ramana Vankayalapati

Theses

This thesis details the electrical characterization of thermally grown thin SiO2 films on virgin and plasma etched silicon surfaces. The electrical characterization techniques employed for the present study are high frequency Capacitance Voltage(C-V) and Current-Voltage(I-V) measurements. The structures used in this study are Al/Polysilicon/SiO2/Si/A1 capacitors fabricated on n-Si and p-Si substrates. These capacitors with areas in the range of 0.001-0.05 cm2, were made using various plasma process conditions and etch reactors.

Based on the experimental results of the C-V anlaysis, in comparison of the controls samples with the plasma treated samples, we could not see …


Electron Field Emission Through A Very Thin Oxide Layer, Guang Yang Dec 1990

Electron Field Emission Through A Very Thin Oxide Layer, Guang Yang

Theses

Field Emission of an emitter covered with a very thin oxide layer is modeled and calculated numerically. The additional barrier due to the oxide layer is included in the tunnelling problem by using the standard WKB method and tunnelling transmission matrix method. The following physical parameters are considered: the oxide barrier height, the oxide conduction band edge electron effective mass, and the oxide dielectric constant. Compared with the Fowler-Nordheim equation, which was derived for a clean metallic emitter, the calculation of this work shows a reduction of the emission current density from an emitter covered with an oxide layer a …