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Articles 180901 - 180930 of 197941

Full-Text Articles in Engineering

Decomposing Non-Product Form Queuing Lattices Through Simulated Annealing, Jr-Chin Lin Sep 1990

Decomposing Non-Product Form Queuing Lattices Through Simulated Annealing, Jr-Chin Lin

Theses

A random, heuristic search called Simulated Annealing is adapted to decompose the state transition lattice of Non-Product Form Queuing Models. Simulated Annealing Algorithm has been successfully applied to a number of optimization problem such as The Traveling Salesman Problem, Graph Partionning, Physical Computer Design, VLSI Chip Design, Image Processing,... etc. It has the advantage over other gradient descent techniques to solve the combinatorial problems. The solution can escape from local minimum by adding Boltzmann Distribution Factor to the algorithm. Most lattice of non-product form queuing models can be decomposed into Solvable Subsets through this algorithm, and solvable subset is the …


Design Of A Cmos Temperature Sensor With Eeprom Error Correction Scheme, Jin-Ku Kang Sep 1990

Design Of A Cmos Temperature Sensor With Eeprom Error Correction Scheme, Jin-Ku Kang

Theses

This thesis describes the design and operation of a CMOS temperature sensor operating at very low power with an EEPROM error correction scheme including the physical layout. This device is designed for applications requiring very low power including biomedical and optically powered device applications. The sensor output is an analog voltage. The temperature sensing cell is implemented with two BJTs having different emitter areas. An op amp dissipating about 300 micro-watts power is designed and is used to amplify the sensor output voltage with a gain of 85dB. A novel EEPROM is used to correct nonlinearity error of the temperature …


Recycling: Separation Of Major Thermoplastics From Postconsumer Plastics Stream, Rafael A. Rodriguez Sep 1990

Recycling: Separation Of Major Thermoplastics From Postconsumer Plastics Stream, Rafael A. Rodriguez

Theses

The complete process for separating Low Density Polyethylene (LDPE), High Density Polyethylene (HDPE), Polyvinyl Chloride (PVC), Polypropylene (PP), Polystyrene (PS), Polyurethane (PU), and Polyethylene Terephthalate (PET) from a mixture of postconsumer plastics materials was presented. The driving forces considered to achieve separation were different densities and selective solubility of plastics in specific solvents.

The proposed process separates Polyurethane and Polystyrene by using aqueous solutions of different densities. On the other hand, the other five plastics are separated using solvents.

Diagrams showing streams and plastics separation in each unit were discussed. Individual material balances for each step were performed for a …


Max/Min : A Novel Rank Order Based Filter Family, Raafat E. Kamel Sep 1990

Max/Min : A Novel Rank Order Based Filter Family, Raafat E. Kamel

Theses

In the early development of signal and image processing, linear filters were the primary tools. Their mathematical simplicity made them easy to design and implement. They also offered satisfactory performance in many applications. However, they show poor performance in other cases, such as image processing.

Nonlinear filtering offered a solution to these problems. Nonlinear filtering has undergone a lot development for a long time. Among the first known nonlinear filters was the median filter, which was proposed by Tukey. Median filter preserves signal or image details better compared to a linear filter. Later other nonlinear filters were developed, including median …


Design And Simulation Of Submicron Microelectronic Vacuum Triodes, Hou-Jun Wang Sep 1990

Design And Simulation Of Submicron Microelectronic Vacuum Triodes, Hou-Jun Wang

Theses

This thesis presents the first design and detailed Simulation of submicron vacuum microelectronic triodes static characteristics. In this thesis a new 5-electrode active device is emphasized.

These devices have potentially important advantages over semiconductor devices. They can be used in extreme environments. The picosecond transit time for internal electron ballistics provide optimism for very fast devices applications. It appears reasonable to fabricate these devices using standard VLSI processing equipment. Further, the micron dimension makes " vacuum microelectronic chips" a reasonable goal.

Devices are characterized for static parameters including electron trajectories, electric field contours, and voltage potential contours. The field emission …


Pc-Based Ft/Icr System, Shenheng Guan, Patrick R. Jones Sep 1990

Pc-Based Ft/Icr System, Shenheng Guan, Patrick R. Jones

Pacific Patents

An apparatus for conducting FT/ICR experimentation and acquiring data using a personal computer and a fast buffer board. The apparatus has the capability of generating an ion excitation signal and acquiring results from the FT/ICR experiment. Those results are then digitized and stored in memory on the fast buffer board. Once the results have been stored in the fast buffer board memory, they are transferred to the personal computer where they can be processed and interpreted by the user.


Relative And Absolute Timing Jitter In Actively Mode-Locked Semiconductor Lasers, Dennis J. Derickson, A. Mar, J. E. Bowers Sep 1990

Relative And Absolute Timing Jitter In Actively Mode-Locked Semiconductor Lasers, Dennis J. Derickson, A. Mar, J. E. Bowers

Electrical Engineering

No abstract provided.


Finite Element Analysis Of Thermal Stresses In Semiconductor Devices, Joachim Karl Wilhelm Duerr Sep 1990

Finite Element Analysis Of Thermal Stresses In Semiconductor Devices, Joachim Karl Wilhelm Duerr

Dissertations and Theses

The failure of integrated circuit due to Silicon fracture is one of the problems associated with the production of a semiconductor device. The thermal stresses, which result in die cracking, are for the most part induced during the cooling process after attaching the die with Gold-Silicon solder. Major factors for stress generation in material systems are commonly large temperature gradients and substantial difference in coefficients of thermal expansion.

This research covers the thermal stresses introduced upon cooling a composite Silicon device. A transient thermal analysis has been performed to determine the temperature gradients. The stress distribution has been investigated. For …


Acuta Enews September 1990, Vol. 19, No. 9 Sep 1990

Acuta Enews September 1990, Vol. 19, No. 9

ACUTA Newsletters

In This Issue

Are colleges aggregators?

President's column

Four workshops scheduled

Revising the directory

A six-node network

Update on Portland


Perceived Risks Versus Actual Risks: Managing Hazards Through Negotiation, Kristin S. Shrader-Frechette Sep 1990

Perceived Risks Versus Actual Risks: Managing Hazards Through Negotiation, Kristin S. Shrader-Frechette

RISK: Health, Safety & Environment (1990-2002)

The author describes what she calls the "Expert-Judgment Strategy", finding that, because it discounts lay perceptions of Risk, it interferes with the acceptance of important but Risky technologies.


Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, September 1990, College Of Engineering And Computer Science, Wright State University Sep 1990

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, September 1990, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

An eight page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.


Optical Processors For Smart Structures, Barry G. Grossman, Howard Hou, Ramzi H. Nassar Sep 1990

Optical Processors For Smart Structures, Barry G. Grossman, Howard Hou, Ramzi H. Nassar

Electrical Engineering and Computer Science Faculty Publications

For underwater fiber-optic sensor arrays containing hundreds of sensors as well as smart aerospace structures and skins using fiber-optic strain sensor arrays, the output of the sensors are optical signals that are a function of the measurand. We are also employing optical signals to energize smart-structure actuators (shape-memory alloys). An all-optical processor would thus seem to be logical choice for the processor since we must simultaneously process, in real time, multiple optical input (sensor) signals and generate multiple output (actuator) signals. In addition, with an all-optical processor, there would be no reduction in processor performance due to converting between optical …


On The Maximum Range Of Flying Wings, Peter J. Torvik Sep 1990

On The Maximum Range Of Flying Wings, Peter J. Torvik

AFIT Documents

The classical equations for determining the maximum range of aircraft with propeller and jet propulsion systems are reviewed, along with previous work conducted to determine the optimal division of aircraft volume between fuselage and wing components. That the jet powered flying wing configuration produces optimal range only for limited geometries is confirmed. The optimal range of aircraft employing high bypass jet engines is explored, and found to lead to a broader range of design parameters for which the flying wing design produces maximum range than is the case when a pure jet system is used.


Studies In The Hybrid Deterministic Parsing, Stan C. Kwasny, Anne M. Johnstone, Barry L. Kalman Sep 1990

Studies In The Hybrid Deterministic Parsing, Stan C. Kwasny, Anne M. Johnstone, Barry L. Kalman

All Computer Science and Engineering Research

This report details research plans to extend work on hybrid deterministic parsing. The approach is hybrid in its combination of symbolic and sub-symbolic (connectionist) approaches. The research is investigating (1) new and more robust architectures for deterministic parsing which are hybrid mixtures of symbolic and sub-symbolic components, (2) combinations of syntax with lexical access and other components of natural language processing in order to determine how the distributed patterns of connectionism may enable better interfaces among these components, and (3) properties of the rules in the rule-based deterministic processing of natural language that make them most suitable for sub-symbolic training. …


Experimental Performance Of A Binary Phase-Only Optical Correlator Using Visual And Infrared Imagery, Samuel Peter Kozaitis, Sandra L. Halby, Wesley E. Foor Sep 1990

Experimental Performance Of A Binary Phase-Only Optical Correlator Using Visual And Infrared Imagery, Samuel Peter Kozaitis, Sandra L. Halby, Wesley E. Foor

Electrical Engineering and Computer Science Faculty Publications

Experimental results of an optical binary phase-only correlator using both visual and IR imagery are presented. The inputs to the correlator originate from actual aerial imagery containing aircraft and a variety of distortions. Filters used as a database for the system are derived from models of aircraft. Digital image processing techniques are used on images before being input into the optical correlator to enhance the performance of the system. Both noise removing and segmentation techniques are investigated. Input images to the correlator are displayed on a 128×128 magneto-optic spatial light modulator (SLM). Experimental results are presented which show that the …


Optimized Cross Correlation Waveforms For First Order Correlation Loops, Kurt Louis Kosbar Sep 1990

Optimized Cross Correlation Waveforms For First Order Correlation Loops, Kurt Louis Kosbar

Electrical and Computer Engineering Faculty Research & Creative Works

In this work, the steady state mean square tracking error of first order correlation loops is minimized by varying the locally generated cross correlation function produced by the voltage controlled oscillator. This analysis should assist in the design of modified first order delay locked loops used for pseudonoise code synchronization in direct sequence spread spectrum receivers. The optimum cross correlation waveform is generated by filtering a replica of the originally transmitted signal. The optimal filter imposes a 90 degree phase shift at all frequencies and has an amplitude response that is a function of the channel signal to noise ratio. …


The Role Of Scientists In Risk Assessment, Halina Szejwald Brown, Robert L. Goble Sep 1990

The Role Of Scientists In Risk Assessment, Halina Szejwald Brown, Robert L. Goble

RISK: Health, Safety & Environment (1990-2002)

The authors argue that Risk assessors belong to a profession and offer an alternative to the 1983 National Research Council model defining Risk assessment. They support and illustrate their model by reexamining three familiar Risk assessments: ethylene dibromide, WASH 1400, and Ice Minus Bacteria.


Comment On "On The Fractal Dimension Of Stream Networks" By Paolo La Barbera And Renzo Rosso, David G. Tarboton, Rafael L. Bras, Ignacio Rodriguez-Iturbe Sep 1990

Comment On "On The Fractal Dimension Of Stream Networks" By Paolo La Barbera And Renzo Rosso, David G. Tarboton, Rafael L. Bras, Ignacio Rodriguez-Iturbe

Civil and Environmental Engineering Faculty Publications

No abstract provided.


Pesticide Use On Utah's Crops, Howard M. Deer, Richard C. Peralta, Majid Ehteshami Sep 1990

Pesticide Use On Utah's Crops, Howard M. Deer, Richard C. Peralta, Majid Ehteshami

Civil and Environmental Engineering Faculty Publications

Utah State University's Cooperative Extension Service has placed high priority on a Water Quality Initiative for Utah. As a part of that emphasis, a research project was initiated to analyze the hazards that agricultural chemicals pose to Utah's ground water. The initial phase of this research was to determine those locations in Utah that are at greatest risk of ground water contamination by pesticides. This was accomplished by interfacing data on pesticide usage with soil and hydrologic factors. The results identified specific areas in the state where potential hazards exist. This report summarizes data on the use of pesticides on …


Analysis Of Traffic Accident Data In Kentucky (1985-1989), Kenneth R. Agent, Jerry G. Pigman Sep 1990

Analysis Of Traffic Accident Data In Kentucky (1985-1989), Kenneth R. Agent, Jerry G. Pigman

Kentucky Transportation Center Research Report

This report includes an analysis of traffic accident data in Kentucky for the years of 1985 through 1989. A primary objective of this study was to determine average accident statistics for Kentucky highways. Average and critical number and rates of accidents were calculated for various types of highways in rural and urban areas. These data can be used in Kentucky's procedure to identify locations that have abnormal rates or numbers of accidents.

Another objective of this study was to provide data which can be used in the preparation of the problem identification portion of Kentucky's Annual Highway Safety Plan. County …


1990 Safety Belt Usage Survey And Evaluation Of Effectiveness In Kentucky, Kenneth R. Agent Sep 1990

1990 Safety Belt Usage Survey And Evaluation Of Effectiveness In Kentucky, Kenneth R. Agent

Kentucky Transportation Center Research Report

The objective of the survey was to establish 1990 safety belt and child safety seat usage rates in Kentucky. Data were collected at 100 sites and combined based on vehicle miles travelled for a given type of highway, rural or urban location, and county population category. Also included in this report is an analysis of accident records evaluating the effectiveness of safety belts.

Statewide usage rates were 32 percent for drivers and front-seat passengers (over 19 years of age) and 57 percent for children under four years of age (front and rear seats). Usage rates had increased significantly in 1990 …


Road Rater Correlation, R. Clark Graves, David L. Allen Sep 1990

Road Rater Correlation, R. Clark Graves, David L. Allen

Kentucky Transportation Center Research Report

In this study, a correlation has been conducted between the Model 400B and the Model 2000 Road Rater. Also contained in this study, is a study of the linearity of the Road Rater measurements. Information gained from this study will provide better understanding of Road Rater measurements.


Irish Building Services News Sep 1990

Irish Building Services News

Building Services Engineering

No abstract provided.


Comparative Analysis Of Single And Double Dwell Acquisition Schemes, Gurinder Singh Ahluwalia Aug 1990

Comparative Analysis Of Single And Double Dwell Acquisition Schemes, Gurinder Singh Ahluwalia

Theses

Single and double dwell pseudonoise (PN) acquisition systems are described, explained and analyzed. These systems are designed to synchronize a locally generated PN signal with a received PN signal of unknown phase in the presence of noise. The mean, variance and an approximate probability distribution function (PDF) of the acquisition time for the single and double dwell PN acquisition schemes is developed. Intuitively, the double dwell acquisition system should be superior to the single dwell system because of the ability to quickly dismiss incorrect cells and further verify probable hits. It is shown analytically that this is in fact true …


Design Of A Microengineered Pressure Sensor, Ranjeet Alexis Aug 1990

Design Of A Microengineered Pressure Sensor, Ranjeet Alexis

Theses

A new family of microengineered vacuum ionization gauges of an approximate volume of 200µ3 has been designed. These devices can he fabricated using existing semiconductor processing capabilities. The focus of this thesis is to scale down the current state-of-the-art for ionization sensors to micron dimensions. These gauges can be manufactured economically and potentially will be integrated with more complex structures and circuitry. In these devices an active ionization volume of micron dimensions is used for launching ions in a trajectory towards a collection electrode. Ionization of gas species is accomplished by an electron flux of sufficient energy. Analysis of …


Improving The Throughput Of Plasticating Extruders : Measurement Of The Interparticulate Friction Coefficient For Polymeric Particulates With Circular And Profiled Cross Sections, Aiping Chen Aug 1990

Improving The Throughput Of Plasticating Extruders : Measurement Of The Interparticulate Friction Coefficient For Polymeric Particulates With Circular And Profiled Cross Sections, Aiping Chen

Theses

This thesis deals with the coefficient of friction between individual polymeric pellets, the interparticulate friction coefficient (IPFC). It has been measured using a shear cell for a wide variety of circular and profiled cross?section pellets for a variery of polymeric materials. First, the thesis explains the reasons why it is desirable to enhance the IPFC based on the melting mechanisms in a single screw plasticating extruder. By making pellets with profiled cross?section pellets, the IPFC is greater than for pellets of circular cross?section. Second, it describes the test apparatus for measuring the IPFC and the method for calculating the IPFC. …


Point Pattern Matching By A Genetic Algroithm, Minghwang Chen Aug 1990

Point Pattern Matching By A Genetic Algroithm, Minghwang Chen

Theses

The problem we consider is to find a subset of points in a pattern that best match to a subset of points in another pattern through a transformation in a least squares sense. Exhaustive search to find the best assignment mapping one set of points to another set is, if the number of points that are to be matched is large, computationally expensive. We develop a genetic algorithm which searches for the best ("almost the best") assignment efficiently. To map the point pattern matching into the framework of a genetic algorithm, we use a fitness function which inversely proportional to …


A Critical Analysis On Cogeneration Policy, R. Tjahjokartiko Gondokusumo Aug 1990

A Critical Analysis On Cogeneration Policy, R. Tjahjokartiko Gondokusumo

Theses

It could be difficult to understand electricity problems without knowing its history; how a combine of legal, administration, and financial means effects electricity in the development. The recent public law on energy-related issues traceable by this study is the Renewable Energy and Energy Efficiency Technology Competitiveness Act of 1989.

In short, cogeneration was proposed to utility (as public property) from industry (as private property) under PURPA (of which National Energy Act is the legislative history). Thus, it should be clear that the problems of cogeneration is not pro or contra issues. It is a national issue. Then, a cogeneration planner …


Decomposing Non-Product Form Queuing Lattices Through Genetic Algorithm, Wei Han Aug 1990

Decomposing Non-Product Form Queuing Lattices Through Genetic Algorithm, Wei Han

Theses

In this paper, a Genetic Algorithm technique is adapted to decompose the state transition lattice of a class of non-product form queueing models. Genetic Algorithms are search algorithms based upon the mechanics of natural genetics. They combine a survival-of-the-fittest among string structures with a structured, yet randomized, information exchange to form a search algorithm with some of the innovative flair of human search. While randomized, genetic algorithms are no simple random walk. They efficiently exploit historical information to speculate on new search points with improved performance. Here genetic algorithms is applied to a non-product queueing lattices optimization problem. Only the …


Performance Evaluation Of Consumer Electronic Bus, Sairaj R. Pakkam Aug 1990

Performance Evaluation Of Consumer Electronic Bus, Sairaj R. Pakkam

Theses

This thesis describes the performance evaluation of the Consumer Electronic Bus proposed by the Electronic Industries Association. To study the behaviour of CEBUS under different traffic conditions, a simulation program was developed modelling the layer architecture of CEBUS. The CEBUS is based on the ISO/OSI model of layered architecture. The simulation results have shown that, when the throughput of the network is small, the delay is bounded for all messages of all priorities. As the throughput of the network increases, under the presence of more high priority messages, the lower priority messages get queued at their nodes. It is also …