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Articles 5311 - 5340 of 5735

Full-Text Articles in Electrical and Electronics

An Intelligent Electrocardiogram Tutoring Package Ekgchallenger, Santosh K. Ananthraman May 1989

An Intelligent Electrocardiogram Tutoring Package Ekgchallenger, Santosh K. Ananthraman

Theses

This thesis presents the development and implementation of an intelligent electrocardiogram tutoring package, namely, EKGCHALLENGER which is meant for use in medical schools to teach medical students a method of diagnosing electro cardiograms.

EKGCHALLENGER is an IBM - PC based, user friendly package. It works in two basic modes. The first is a tutorial mode wherein the user is taught the step-by-step diagnosis of electrocardiograms ( EKGs ) which are presented in order of increasing difficulty. The second is the challenger mode wherein the user is asked to diagnose EKGs which are randomly chosen from an EKG database. The diagnosis …


Statistical Multiplexing Of Video Sources For Packet Switching Networks, Krishna Kancherla May 1989

Statistical Multiplexing Of Video Sources For Packet Switching Networks, Krishna Kancherla

Theses

Communication networks are fast evolving towards truly integrated networks handling all types of traffic. They employ integrated switching technologies for voice. video and data. Statistical or asynchronous time division multiplexing of full motion video sources is an initial step towards packetized video networks. The main goal is to utilize the common communication channel efficiently, without loosing quality at the receiver. This work discusses the concept of using statistical multiplexing for packet video communications. The topology of a single internal packet network to support ISDN services has been adopted. Simulations have been carried out to demonstrate the statistical smoothing effect of …


Rays And Beams Near The Shadow Boundary, Weixing Gao May 1989

Rays And Beams Near The Shadow Boundary, Weixing Gao

Theses

Asymptotic techniques in wave propagation problems exhibit attractive features in computational aspects compared to numerical methods. However, they experience problems in complicated environments due to the transition regions associated with them. The transition region involving a shadow boundary in the downward refractive index profile has been investigated. The ray paths were determined solving the ray equation analytically. The Green's function due to a line source is constructed and evaluated using numerical integration (reference solution) and asymptotic techniques. Then, the field produced by the source, is synthesized, using superposition of beams generated from complex source point representation. The floating parameters such …


Schottky-Barrier Solar Cells, Surface Patterning For Efficient Light Collection, Constantinos Manolis May 1989

Schottky-Barrier Solar Cells, Surface Patterning For Efficient Light Collection, Constantinos Manolis

Theses

Different geometrical surface configurations are considered here for a Au/n-Si semiconductor Schottky-barrier solar cell to improve their light collection efficiency.

Optical and electrical properties are theoretically analyzed for two given optical wavelengths of 0.9 and 0.5 micrometers respectively.

The configurations considered are: V-shaped, Star- shaped, M-shaped, asymmetric-V-shaped, and asymmetric-M-shaped. They all show a significant improvement in the short-circuit current over a flat cell model, while the open-circuit voltage remains practically unchanged.


Computer Controlled Oxygen Bioreactor, Dinesh Sachdeva May 1989

Computer Controlled Oxygen Bioreactor, Dinesh Sachdeva

Theses

A computer controlled oxygen bioreactor has been designed to obtain more accurate values for oxygen bioreactor requirements and to optimize oxygen productivity with respect to oxygen concentration. This study solves a specific problem relating to oxygen concentration measurement and bioreactor control. The proposed reactor system is computer controlled to insure a desired oxygen concentration supply to an oxygen consuming reaction or organism. This thesis also explains and illustrates the bioreactor and its computer control system.

The computer controller incorporates oxygen sensing, oxygen measurement and temperature measurement, Electrical circuits have been designed and built for proper signal conditioning, data acquisition, data …


Trellis Encoded M-Ary Partial-Response Schemes, Raju P. Patel May 1989

Trellis Encoded M-Ary Partial-Response Schemes, Raju P. Patel

Theses

Convolutional codes can be used to improve the reliability of partial-response channels in a Gaussian noise environment. Multilevel partial-response schemes can be used to increase the information rate in a given bandwidth compared to binary partial-response schemes. This thesis deals with the theory and construction of convolutionally encoded 4-ary partial- response schemes. The free Euclidean distance of the combined trellis of rate-1/2 convolutional code and 4-ary partial-response scheme is found through a computer search, using the Viterbi-algorithm.

The matched encoding concept is also applied to find the conditions for matched encoding for combined trellis of rate-1/2 convolutional codes and 4-ary …


Hardware And Software Designs For Integrated Electrical Engineering Experiments, Sujin Pramojaney May 1989

Hardware And Software Designs For Integrated Electrical Engineering Experiments, Sujin Pramojaney

Theses

The interfacing between the various electrical engineering fields is not emphasized in the electrical engineering laboratory; the traditional aim of a laboratory course is to complement a single theoretical course. The object of this thesis is to provide means, hardware and software, that can be used in different system configurations to perform useful industrial tasks. The chosen task is to control electrical machines using a microcomputer. Experiments can be written to be performed by students, using these systems. The emphasize of these experiments can be on the characteristics of a power electronics device, but the device will be seen as …


Network Realizability Approach To Robust Stability Of Discrete-Time Systems Characterized By Polynomials, Sri Indran Rasiah May 1989

Network Realizability Approach To Robust Stability Of Discrete-Time Systems Characterized By Polynomials, Sri Indran Rasiah

Theses

In system design, the coefficients of a characterizing polynomial are usually not precisely known but can be bounded from above and below by real numbers. The requirement of robust system design from the stability standpoint demands, then, the guaranteeing of the stability of a set of polynomials.

Stability theorems for continuous-time systems and discrete-time systems, are studied in this report. It is shown that one more condition has to be included into each of the theorem. The revised theorem for continuous-time systems is proved through network realizability theory. The one for discrete-time systems is, then, proved via the use of …


Study Of Ionized Cluster Beam Techniques For Reactive Deposition Of Gallium Nitride Thin Films, Jyh Sheen May 1989

Study Of Ionized Cluster Beam Techniques For Reactive Deposition Of Gallium Nitride Thin Films, Jyh Sheen

Theses

This thesis is divided into two parts. The first part investigates the Ionized Cluster Beam( ICB ) technique through measurements of the energy of ionized gallium beam. The presence of ions and their kinetic energy in the ICB technique is advantageous in the formation process of thin film. The results of retarding potential measurement are comparable with the presence of clusters as large as 500 atoms. The second part examines the formation of gallium nitride thin film. In order to enhance the reaction of gallium and nitrogen, dissociation of molecular nitrogen by microwave discharge method was used to generate atomic …


Electrical Insulation Screening For Reliability, Vinu Sundaresan May 1989

Electrical Insulation Screening For Reliability, Vinu Sundaresan

Theses

This thesis work includes an investigation on the use of electrical noise for the screening of dielectric sheet material for reliability. Three different high voltage insulation sheet materials, commonly used in power industry, have been studied. These are - Westinghouse Polyester resin coated glass cloth, Dupont ‘NOMEX' aramid calendared paper and a cotton rag commonly known as Fishpaper. Samples of each material have been categorized into low noise and high noise units. Subsequently, these samples were subjected to accelerated life testing.

It is seen that units having high noise are failing quicker compared to low noise units when subjected to …


Design Of Governor-Turbine Models In Stability Studies, Vidyanand Swaminathan May 1989

Design Of Governor-Turbine Models In Stability Studies, Vidyanand Swaminathan

Theses

This thesis investigates the effect of hydro governor-turbine models on the steady state stability of an automatically controlled electric power system. Basically two kinds of hydro governor-turbine models, namely, Impulse and Francis type are studied in depth. Design of a compensating network has also been proposed, which can help improve the stability conditions of a power system which employs a poor governor-turbine model.

The power system investigated includes a large sized hydro generating unit connected to an infinite bus via a power network. This generator employs a modern three-channel fast-acting automatic voltage regulator (AVR). For any operating condition, stability results …


Analysis On Dielectric Resonators, Xuan Tu May 1989

Analysis On Dielectric Resonators, Xuan Tu

Theses

This dissertation deals with the studies and analysis of Dielectric Resonators (DR). A shielded dielectric iesonator structure, consisting of the substrate, the spacer, the dielectric resonator and the metallic shielding is modelled theoretically. The theoretical expressions for the resonance fields are derived by using radial-mode matching and axial mode-matching techniques. In these techniques, the structure is divided into partial regions and the fields in each pai tial region are represented in terms of a series of the appropriate modes with unknown coefficients. Matching the adjacent regions yields a system of linear or nonlinear equations — which then are solved. The …


Image Coding With Quantization Noise Feedback, Jen-Chieh Wang May 1989

Image Coding With Quantization Noise Feedback, Jen-Chieh Wang

Theses

A progressive image transmission based on Laplacian pyramid structure is used for the scheme of quantization noise feedback. Because a reduction in transmission rate inevitably increases the quantization noise and degrades the image quality, the designer of the quantizer laces the dilemma of balancing the transmission rate and the quantization noise. Using the algorithm of noise feedback will reduce the quantization error without appreciably increasing transmission rate. Uniform quantization and nonuniform quantization rate used to compare the result with or without noise feedback. In the transmitter end, the original image can be reduced by a certain procedure to form a …


Spectrum Analysis Of Heart Rate Variability, Xuming Wang May 1989

Spectrum Analysis Of Heart Rate Variability, Xuming Wang

Theses

This research investigated the respiratory influence on heart rate variability. The heart rate spectrum was obtained from the heart rate variability signal which was extracted from the electrocardiogram We then studied the magnitude of the respiration peak in the heart rate spectrum and examined the dependence of the magnitude of this peak on breathing frequency, subject and day.

An experiment designed to simultaneously acquire the electrocardiogram and the respiration signal was conducted on ten people ranging from 22 to 55 years of age (3 females, 7 males). Three tests were performed on each subject. In each test, 2 different postures …


Efficient Design Of Trellis Coded Cpfsk, Hsinhsyong Yang May 1989

Efficient Design Of Trellis Coded Cpfsk, Hsinhsyong Yang

Theses

In this thesis convolutional coded continuous-phase frequency shift keying (CPFSK) is studied.

CPFSK which is a subclass of continuous phase modulation ( CPM ) is a constant amplitude digital modulation scheme with very good spectral characteristics.

A new method, called matched encoding, that combines convolutional codes and CPFSK is studied. With the maximum free Euclidean distance as the optimization criterion, the best combined coded schemes were found for the same rate of the codes and given total number of states in the optimum decoder.

A different method which was suggested by Rimoldi[7], called the decomposition method, is also described in …


Methods Of Achieving High Speed On Data Flow Machines, Chung-Lin Yu May 1989

Methods Of Achieving High Speed On Data Flow Machines, Chung-Lin Yu

Theses

Simultaneity is a key to high speed and large computation. Assuming hardware components of a given speed, it is the only remaining consideration in achieving raw speed. Simultaneity can be shackled by dependencies, however, and years of hardware and software work have been devoted to understanding the types of dependencies and how they can be obeyed or removed from a computation.

In this thesis, the principles of the data flow machines and the structure of the data flow languages are illustrated. Various methods of achieving high speed are discussed. These methods include streams, Lenient Cons (I-structure), and dependence-driven computation, which …


Image Coding With Switchable Dynamic Quantizers, Shing-Sun Yu May 1989

Image Coding With Switchable Dynamic Quantizers, Shing-Sun Yu

Theses

In this thesis, an image coding scheme based upon dynamic quantizations and Differential Pulse Code Miodulalton (DPCM) is studied for application in digital image transmission. This scheme achieves a degree of data compression, and at the same time, maintains an acceptable degraded Mean Square Error (MSE) in the reproduced image. The image to be transmitted is first divided into blocks and each block is then quantized before transmission. The dynamic quantizations including DPCM) are dynamically utilized in reducing the transmission rate while maintaining a desirable quantization noise level. Results of computer simulation of the proposed scheme demonstrate that the switchable …


Caldac, A New Approach To Computer-Assisted Theatrical Lighting Design, David William Zalewski May 1989

Caldac, A New Approach To Computer-Assisted Theatrical Lighting Design, David William Zalewski

Theses

CALDAC, which stands for Computer-Assisted Lighting Design and Control, is a design environment integrating two present day state-of-the-art theatrical lighting computer aides, the computer-aided design (CAD) program and the preset storage system. The CALDAC environment also features On-Screen Stage Simulation, a newly proposed design tool. It is shown that this integration offers a strong advantage to the lighting designer and his/her crew.

The thesis begins by introducing the concepts of theatrical lighting design and the evolution of computerized control. The basics of CAD for the lightplot design are presented, followed by an introduction to the concepts of on-screen stage simulation. …


Unified Study Of Trellis Encoded Correlative-Fm, K. Narendra Bhat May 1989

Unified Study Of Trellis Encoded Correlative-Fm, K. Narendra Bhat

Theses

Trellis encoding of correlative-FM is studied from the point of view of the overall structure, performance, bandwidth occupancy, and complexity. Here, correlative (partial-response) coding is used to improve the bandwidth efficiency of MSK (Minimum-Shift Keying) at the expense of performance. Then, trellis codes are used to improve the error-rate performance of the corresponding correlative-FM scheme with little or no increase in bandwidth occupancy (compared to uncoded MSK). In a sense, this is similar to Ungerboeck's coding for (memoryless) PSK modulation.

A new encoding approach, called matched encoding, is used here that produces trellis coded modulations achieving greater coding gains than …


Non Invasive Monitoring Of Cardiovascular Dynamics Through A Microwave Interferometer, Suresh Chakravarthi May 1989

Non Invasive Monitoring Of Cardiovascular Dynamics Through A Microwave Interferometer, Suresh Chakravarthi

Theses

The microwave interferometer is utilized to pick up vibrations of the anterior (front) chest wall, produced by cardiac activity. This instrument is capable of remotely measuring the vibrations at distances up to four feet through clothing, by using low level microwave energy at 9.3 Ghz. The vibrations picked up from subjects are filtered, and processed through a PC to correlate with EKG signals, and thereby evaluate the instrument as a non-invasive, non-contacting cardiac monitor.

The subjects lie on their back with the microwave energy illuminating their chest, and their cardiovascular dynamics are recorded simultaneously with EKG signals. The EKG is …


Implementation Of The Sliding Dictionary Data Compression Algorithm On An At&T Dsp 32 Digital Signal Processor, Shu Fang May 1989

Implementation Of The Sliding Dictionary Data Compression Algorithm On An At&T Dsp 32 Digital Signal Processor, Shu Fang

Theses

Compared with other data compression algorithms, the sliding dictionary is more practical for implementation in hardware. After a comprehensive study of the algorithm, an on line data compression scheme which uses AT&T DSP 32 Digital Signal Processor has been developed. Assembly language programs for encoder and decoder have been written and tested. The whole compression system has been simulated in a real-time environment and results have been obtained. A quantized coding scheme has been used to increase compression ratio. Separate assembly language programs have been written to implement the quantized coding scheme and tested. Results obtained from real-time simulation are …


One-Dimensional Parametric Inverse Scattering For Lossless Dispersive Media, Frank Gangi May 1989

One-Dimensional Parametric Inverse Scattering For Lossless Dispersive Media, Frank Gangi

Theses

In this thesis, the effects of high frequency noise on a perturbational inversion algorithm for a stratified dispersive medium are investigated. It is shown that the perturbational algorithm becomes unstable under high frequency noise. The physical origin of this instability is discussed.

In order to enhance the robustness of the perturbational inverse scattering solution, a parametric inversion algorithm is implemented. The improvement by the use of a parametric inversion is given quantitatively by the profile-to-error ratio (PER). Examples of the two-pole and the three-pole reflection coefficients are compared and contrasted.


A Decomposition Algorithm For The State Transition Lattices Of Certain Non-Product Queueing Protocols, Cheng-Kuo Hong May 1989

A Decomposition Algorithm For The State Transition Lattices Of Certain Non-Product Queueing Protocols, Cheng-Kuo Hong

Theses

In this thesis, an algorithm is developed to decompose the state transition lattice of a class of non-product form queueing models. Here only the lattices of regular type A structure are considered. By applying the algorithm, the lattice is decomposed into solvable subsets which can be solved sequentially.


Modelling And Parameter Estimation In Clinical Electrooculography, Shengche Hsu May 1989

Modelling And Parameter Estimation In Clinical Electrooculography, Shengche Hsu

Theses

The Corneoretinal potential (CRP) was discovered in 1848. Its response to changes in light intensity can provide information relevant in the diagnosis of some retinal degenerative disorders. The indirectly measured CRP is referred to as electro-oculography (EOG). A system for automatic data acquisition and modelling, providing graphic presentation, data processing and file management, has been developed. A linear feedback model is proposed to represent the dynamics of the EOG signal. Model parameters are estimated by the nonlinear least-square method. The effect of measurement time on the reliability of parameter estimation is discussed.


Csma/Cd Lan Performance : Modeling And Simulation In Csim, Nanda K. Kanuri May 1989

Csma/Cd Lan Performance : Modeling And Simulation In Csim, Nanda K. Kanuri

Theses

A simulation model to analyze the performance of CSMA/CD protocol is developed. CSIM, a process oriented simulation language, is used. Performance measures such as throughput, average delay and maximum delay per packet are presented. System performance is analyzed for different loads, number of stations, and network lengths, with packet length as parameter. By trading off the throughput and delay time, an optium packet length can be selected from simulated performance curves. A general scheme for MAC protocols modeling is provided.


Output Feedback Applied To Observer Based Controller, Nainn-Ping Ke May 1989

Output Feedback Applied To Observer Based Controller, Nainn-Ping Ke

Theses

This thesis presented the results of an investigation on the stability robustness issues of the Infinite-horizon linear-quadratic-Gaussian (IH-LQG) control system design methodology. The goal of this research deals with the design of Observer based controller using Output Feedback (00F), and this is a new method to solve estimation problems. The primary difference of this method from others is that the estimator is considered as a system. The results of this research shows that the optimal output feedback control law and the optimal state estimator can be designed by the optimal output feedback control method, and shows that the OOF Weighting …


A Cmos Robotic Lan Interface Integrated Circuit Design, Yong-Bin Kim May 1989

A Cmos Robotic Lan Interface Integrated Circuit Design, Yong-Bin Kim

Theses

This thesis describes the design including specification, schematics,logic and circuit simulation, and standard cell layout for a CMOS mixed-mode I.C. for interfacing sensors into a robotics local area network. The network accepts up to 256 interface chips as nodes in each area. A simple network protocol permits acquisition of digital data from the interface nodes through gateways into ARCNET and MAP.

The sensor chip interfaces directly from analog signals of range 0-1V and 0-20mV. It contains an 8-bit ADC. The application I.C. interfaces to sensors for pressure, tactile stress, humidity, temperature, etc.

Each of the sensor interface node I.C.s is …


Visual System Modeling And System Response Analysis, Zhongquan Li May 1989

Visual System Modeling And System Response Analysis, Zhongquan Li

Theses

Based on the anatomical structure, a structural model of the visual system was established. System responses of different stimulations were analyzed based on the model. More extensive study was made on the system impulse response. A mathematical model with parameters representing prominent process components was developed to represent the system response in a compact form and the parameters were statistically studied to correlate to the real physiological characteristics of the visual system. The parameters of the model were used to fit the system intensity response function. The result shows that it is a more quantitative way to construct the system …


Study Of System Dynamics In A Primitive Identification/Counter Model, Zofia Monczka May 1989

Study Of System Dynamics In A Primitive Identification/Counter Model, Zofia Monczka

Theses

Previous study of a simplified identification/counter model (1), (2) indicated bifurcations in its behavior. In order to study this topic, graphical representations of the system dynamics are derived. Analysis of the structure of the identification/counter model reveals the reasons why the graphs assume their given shapes.

The graphical representations of the system are used to characterize the system behavior and thus explain the bifurcations previously encountered. These representations are then used as the basis for deriving a general model for system behavior. Analysis of this model for a specific range of parameter values indicates that the system contains numerous additional …


A Dynamic Cmos Programmable Logic Device, Praveen K. Parvathala May 1989

A Dynamic Cmos Programmable Logic Device, Praveen K. Parvathala

Theses

This thesis presents the design of a Dynamic CMOS Programmable Logic Device chip (NJIT PLD). The main feature of the chip is its reconfigurability and the provision of a processor interface which makes the chip capable of performing coprocessor like functions. The chip has been designed to be used with the Intel 8088 microprocessor, but may also find stand-alone applications. Provision is made for dynamic reconfiguration of the chip. The configuration data for the chip comes from a serial PROM, to which the chip sends a synchronizing clock. The NJIT PLD is a high performance, digital integrated circuit. It has …