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Articles 2281 - 2310 of 3460
Full-Text Articles in Engineering
Image Coding With Quantization Noise Feedback, Jen-Chieh Wang
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
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 …
Trellis Coded Partial-Response Channels, Kumari Yalamanchili
Trellis Coded Partial-Response Channels, Kumari Yalamanchili
Theses
Binary partial-response channels with transfer functions (1+D), (1-D) and (1 — D2) are intersymbol-interference channels which find applications in baseband data communications and magnetic recording systems (tapes, discs, compact discs, etc.). In this thesis we develop a coding technique for improving the reliability of digital transmission over noisy partial-response channels with the above transfer functions. We do so by introducing a new concept, called matched encoding, which arises in the context of trellis coding for channels with memory.
We use inner and outer trellis coding of the partial-response channels. The inner codes called matched inner coset codes, are …
Methods Of Achieving High Speed On Data Flow Machines, Chung-Lin Yu
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
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
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. …
High Temperature Resistant Crosslinked Phenol, O-Chlorophenol And Formaldehyde Copolymer Fiber, Suh Joon Han
High Temperature Resistant Crosslinked Phenol, O-Chlorophenol And Formaldehyde Copolymer Fiber, Suh Joon Han
Theses
Phenolic copolymer fibers which possess clearly distinguishable physical and chemical properties from other synthetic and natural fibers were prepared. Acid catalyzed condensation polymerization of phenol, formaldehyde and o-chiorophenol was carried out by a two-stage polymerization. Initially, phenol-formaldehyde and o-chlorophenol-formaldehyde oligomers were separately prepared by refluxing the corresponding monomers at 100°C under strong agitation. At the second stage, these two oligomers were combined and vacuum-distilled to form a block copolymer which was then melt spinned into fibers and subsequently cured by succinyl chloride in a mineral spirit. Using a flame test and thermogravimetric analysis, it was found that these cured fibers …
Transverse Electric (Te) And Transverse Magnetic (Tm) Mode Conversion In Optically Active (Chiral) Embedded Polymeric Waveguides, Mingdeh Chien
Transverse Electric (Te) And Transverse Magnetic (Tm) Mode Conversion In Optically Active (Chiral) Embedded Polymeric Waveguides, Mingdeh Chien
Theses
Wave propagation in an optically active isotropic, polymeric thin film waveguides is studied. The waveguides are fabricated using the dipping method. Thin film layers are composed of a passive PMMA (poly methyl methacrylate) host material and a chiral, optically active, ((s)-(+)-1,1'-Binaphthyl-2,2'-dily hydro phosphate), guest material. Experimental results show about 1° per centimeter rotation of polarization as light propagates through a 1.8cm waveguide. The theoretical analysis of the mode structure and wave propagation in the waveguide are examined using first order coupled mode theory. TE (-4 TM mode converter is a typical application of this investigation.
Csma/Cd Lan Performance : Modeling And Simulation In Csim, Nanda K. Kanuri
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.
Hardware And Software Designs For Integrated Electrical Engineering Experiments, Sujin Pramojaney
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 …
Design Of Governor-Turbine Models In Stability Studies, Vidyanand Swaminathan
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 …
Design Of A Gear Driven Anti-Twister Mechanism For A Seal-Less Blood Processor, Ajit Nachiket Dastane
Design Of A Gear Driven Anti-Twister Mechanism For A Seal-Less Blood Processor, Ajit Nachiket Dastane
Theses
This thesis presents the design of a gear driven anti- twister mechanism for a blood cell separator. The anti- twister mechanism allows for continuous feed and discharge lines that are rigidly attached to the rotating centrifuge head, thus eliminating the need of rotating seals. It is anticipated that the device using a gear driven anti-twister mechanism will have smoother power transmission and closer rpm tolerances.
In addition, a procedure for the dynamic analysis of the existing device, which uses a belt-driven anti-twister mechanism, is developed. The experimental values obtained from the device are compared with the theoretical values obtained by …
Recirculation Flow Bioreactor For The Synthesis Of Nitroxide And N-Oxide Pharmaceuticals, Douglas Lischick
Recirculation Flow Bioreactor For The Synthesis Of Nitroxide And N-Oxide Pharmaceuticals, Douglas Lischick
Theses
An investigation of the properties of calcium alginate immobilized hog liver microsomes, rich in FAD-containing mixed function oxidase, was performed. Studies involving catalyst storage, immobilization of cofactors within the matrix, and alginate gel concentration were performed using a 1.8 ml mixed flow micro assay reactor. A recirculation flow reactor was designed and used for the biochemical production of 2,2,4,4-tetramethyl-1,3-oxazolidine-l-oxyl, a potentially useful MRI contrast agent.
The activity of the immobilized microsomes was found to increase over time when stored in CaCl2 or in buffer at 4-8°C. The increase in activity is a result of the removal of inherent inhibitors …
Integrated Voice/Data Services On Multihop Radio Networks, Chialun Lu
Integrated Voice/Data Services On Multihop Radio Networks, Chialun Lu
Theses
Integrated voice/data is the first step toward Integrated Services Digital Networks (ISDN). Various techniques have been proposed and analyzed for multiplexing voice and data over a large bandwidth channel. Network efficiency 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 Dynamic Programming. Computer simulation shows that optimal policy minimizes the data delay.
Environmental Impact Assessment For Water Resources Projects : Planning Procedure And Analytical Methods, Mahadesh C. Tumkur
Environmental Impact Assessment For Water Resources Projects : Planning Procedure And Analytical Methods, Mahadesh C. Tumkur
Theses
This thesis presents a state of the art review of environmental impact assessment procedures utilised in the water resources projects which have evolved over the past two decades. The methodologies employed and some of their limitations which exist and are inherent in both the planning and assessment phases of analysis are identified. The above was supplemented by an investigation of the various views of professionals currently employing the above methodologies. The review effort summarizes the relevant information obtained from the literature which is rather dynamic because of the ever evolving nature of the field. One conclusion drawn from this study …
A Study Of The Effect Of Some Inhibitors On The Corrosion Rates Of Austenitic Stainless Steels In Sulfuric Acid, Shang-Yinn Chiou
A Study Of The Effect Of Some Inhibitors On The Corrosion Rates Of Austenitic Stainless Steels In Sulfuric Acid, Shang-Yinn Chiou
Theses
Four sulfur-containing and three nitrogen-containing organic compounds have been tested as inhibitors for four different austenitic stainless steels-SS304, S5316, SS317L, and SS41O-in 10-50 weight% sulfuric acid solutions respectively. Results confirmed that the sulfur-containing compounds were more effective than the nitrogen-containing compounds. The effect of sodium iodide additions on the behaviours of two of the nitrogen-containing compounds was also studied. The synergistic effect caused by the 1 ion was essential for nitrogen-containing compounds as inhibitors in sulfuric acid solution.
Statistical Multiplexing Of Video Sources For Packet Switching Networks, Krishna Kancherla
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
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 …
Estimation Of Thermodynamic Properties Of Petroleum Fractions To Supplement The Aspen Simulator, Steven E. Sund
Estimation Of Thermodynamic Properties Of Petroleum Fractions To Supplement The Aspen Simulator, Steven E. Sund
Theses
The objective of this study was to develop a method of estimating hydrocarbon pseudocomponent data in a format that is consistent with the ASPEN simulator. Although algorithms exist to estimate the pseudocomponent properties, no comprehensive program exists for the public version of ASPEN. A computer program was developed which will take a minimum of input data and can generate the necessary pure component properties for an ASPEN simulation. The program is meant to complement the ASPEN simulator, so the input is similar to ASPEN's input. The output can be incorporated directly into an ASPEN input or can be of the …
Laboratory Model Studies Of Pneumatic Fracturing Of Soils To Remove Volatile Organic Compounds, Panayiotis Papanicolaou
Laboratory Model Studies Of Pneumatic Fracturing Of Soils To Remove Volatile Organic Compounds, Panayiotis Papanicolaou
Theses
Bench-scale laboratory studies were conducted from January 1988 to October 1988 to demonstrate the feasibility of using Pneumatic Fracturing* to enhance the removal of Volatile Organic Compounds from the vadose soil zone. Experiments were conducted to investigate: 1) The effect of pneumatic fracturing on the rate of contaminant removal; and 2) the injection pressures required to initiate soil fracturing.
Contaminated soil was placed and compacted in three identical 15 inch square by 30 inch high plexiglass tanks. The first tank was equipped with a vapor extraction system consisting of vacuum and/or positive air injection. The second tank was equipped with …
A Dynamic Cmos Programmable Logic Device, Praveen K. Parvathala
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 …
Efficient Design Of Trellis Coded Cpfsk, Hsinhsyong Yang
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 …
A Wideband Continuous Phase Shifter For Ka-Band, William J. Tanis
A Wideband Continuous Phase Shifter For Ka-Band, William J. Tanis
Theses
The design, fabrication and test of a 45 degree microstrip phase shifter capable of full Ka-band performance is presented. The design uses a Lange coupler with two ports terminated with beam-lead varactor diodes to provide continuous phase shift. Although this concept has been employed at X-band and below, this thesis demonstrates its feasibility for wideband use at frequencies as high as 40 GHz. The design uses thin-film capacitors, beam-lead diodes, simulated grounds, and air bridges to achieve a planar geometry and to simplify the production process. Detailed test results using various test circuits are shown for comparison to actual phase …
Molecular Modeling In Anatoxin And Other Semirigid Agonists, Wen-Chung Shang
Molecular Modeling In Anatoxin And Other Semirigid Agonists, Wen-Chung Shang
Theses
Conformational search and molecular mechanics calculations were combined to investigate the structural flexibility of isoquinolone, the anatoxin series, and the ferruginine series. Ring searching allow all rational conformations to be generated.
Isoquinolone shows conformational similarity to isoarecolone but is much less potent which suggests that the proximity of the methyl group beta to the carbonyl groups affects the bioactivity of isoquinolone. The very active agonist-anatoxin, without a similar conformation as isoarecolone, shared a similar electrostatic potential contour in the vicinity between the two atoms connected to the electro-positive nitrogen and hydrogen bonding site. These phenomena were not found in ferruginine …
A Methodology For Designing Spacecraft Onboard Processing Systems, Mohammad Nadeem Ahmad
A Methodology For Designing Spacecraft Onboard Processing Systems, Mohammad Nadeem Ahmad
Theses
A three layer methodology is presented for designing spacecraft onboard computer systems. The system design is perceived as a sequence of three hierarchical layers: the Dedicated Processing Layer, the Application and Support Processing Layer, and the Communications Processing Layer. Each layer implements a distinct set of functions and offers services at different levels of abstraction. As opposed to the ISO/OSI Reference Model, where the prime objective is to implement peripheral interaction between two systems, the layered approach used here is to address the problems in system design itself. The problem is approached in a bottom-up fashion, starting with the description …
A Microcomputer Based Non-Invasive Cardiopulmonary Monitor Using A Microwave Interferometer, Tanmoy K. Basu
A Microcomputer Based Non-Invasive Cardiopulmonary Monitor Using A Microwave Interferometer, Tanmoy K. Basu
Theses
With a microwave interferometer the vibrational velocity of the anterior (front), as well as posterior (back) chest wall can be monitored and recorded. The recorded signals are a reflection of the mechanical cardiac activity within the chest cavity, as opposed to Electrocardiogram (ECG) which is a reflection of the electrical cardiac activity. The interferometer recordings are obtained with no physical contact between the instrument and the subject. Moreover, the subject can be fully clothed since microwave energy readily passes through normal dry clothing.
A microwave interferometer that is capable of detecting the vibrational velocity of the surfaces of the chest …
Design Of A Temperature Sensor For Gallium Arsenide Ic Applications, Raviprakash Raviprakash Gutala
Design Of A Temperature Sensor For Gallium Arsenide Ic Applications, Raviprakash Raviprakash Gutala
Theses
This thesis presents the design of a temperature sensor circuit including sensor, differential amplifier, and a memory element for gallium arsenide IC standard cell applications. A standard 1-um depletion-mode GaAs MESFET technology has been used for the design of the circuit. The circuit is intended to be used as a standard cell in GaAs les providing an alarm when the sensor temperature reaches 125 °C. The circuit includes a NAND latch which is set when the chip cell temperature reaches 125 °C. The output of the latch can be sensed by additional circuits (on or off the GaAs chip) which …
Progressive Transmission Of Images Using Pyramidal Structure, Chin-Hua Hsu
Progressive Transmission Of Images Using Pyramidal Structure, Chin-Hua Hsu
Theses
A progressive image transmission scheme based upon Laplacian pyramid structure is used for image coding over low-bandwidth channels. The filtering and differential pulse code modulation (DPCM) methods of image coding are generalized to allow quantization of the Laplacian images. Filtering is performed with a local, symmetric weighting function. The three different quantizers, (1) scalar quantizer, (2) memoryless vector quantizer (VQ), and (3) finite state vector quantizer (FSVQ), are used here to compare the results. In the receiver end, the image can be reconstructed using reverse procedure. The reconstructed image is not the same as the original image because of the …
Microprocessor-Based Processing Unit Implemented By Xilinx Programmable Logic Array, Lee Chuan Hu
Microprocessor-Based Processing Unit Implemented By Xilinx Programmable Logic Array, Lee Chuan Hu
Theses
The 8052 microprocessor-based processing unit is a super single board computer with many unusual features: memory page selecting with page indicators, on-board EPROM/PROM programmer, real time clock, battery back-up RAM, and memory mapped I/O. It is implemented by using Xilinx programmable logic array and can be used for various instruments. Xilinx user-programmable Application-Specific Integrated Circuit (ASIC) is a large logic array with up to 9000 equivalent gates. The advantages of programmable logic devices over standard ICs are more flexibility, design security, lower cost, higher performance, reduced power consumption, smaller size, and increased reliability. The system development time is also greatly …
Ionitriding To Improve The Wear Resistance Of Ferrous Materials, Ravi K. Kodali
Ionitriding To Improve The Wear Resistance Of Ferrous Materials, Ravi K. Kodali
Theses
In this work the effect of ionitriding treatment on wear resistance of ferrous materials was studied. A basic understanding of the ionitriding concepts were given and the advantages of this process over other conventional nitriding treatments were outlined. The effect of various parameters like gas composition, temperature, pressure, process duration and power density on the metallurgical aspects of this process were discussed. Under technical aspects of this technology, advantages of pulsed direct current over conventional direct current nitriding systems were given. In this work wear tests were performed on components made from gray cast iron, alloy steel (AISI 4340), and …