Engineering Commons^™

Saam: The Strategic Asset Allocation Model, Judy Lewis, Todd Gamble, John Tai

All Computer Science and Engineering Research

Asset Allocation has become a dominant factor for investment strategies in recent years. It has found that by holding a strategically diversified portfolio, a high total return on investments can be maintained while, at the same time, reducing portfolio volatility. With recent federal regulations mandating pension investment responsibilities, appropriate asset allocation has become more important than ever. SAAM is a software package specifically designed to be used as a tool to aid the investment professional in determining pension portfolio allocations. SAAM uses the expect system shell CLIPS, has a user-friendly interface, displays output graphically, and runs within the confines of …

Dendrite Spacings In Directionally Solidified Superalloy Pwa-1480, M. Vijayakumar, Surendra N. Tewari, James E. Lee, P. A. Curreri

Chemical & Biomedical Engineering Faculty Publications

Primary dendrite spacings and side-branch coarsening kinetics were examined in specimens of the single-crystal multicomponent commercial superalloy PWA-1480, which were directionally solidified in a positive thermal gradient. The experimentally observed dependence of primary dendrite spacings and side-branch coarsening kinetics on growth rate and thermal gradient were in agreement with the behavior predicted by analytical models developed for binary alloys.

Convex Bayes Decision Theory, Wynn C. Stirling, Darryl Morrell

Faculty Publications

The basic concepts of Levi's epistemic utility theory and credal convexity are presented. Epistemic utility, in addition to penalizing error as is done with traditional Bayesian decision methodology, permits a unit of informational value to be distributed among the hypotheses of a decision problem. Convex Bayes decision theory retains the conditioning structure of probability-based inference, but addresses many of the objections to Bayesian inference through relaxation of the requirement for numerically definite probabilities. The result is a decision methodology that stresses avoiding errors and seeks decisions that are likely to be highly informative as well as true. By relaxing the …

Set-Valued Filtering And Smoothing, Wynn C. Stirling, Darryl Morrell

Faculty Publications

A theory of discrete-time optimal filtering and smoothing based on convex sets of probability distributions is presented. Rather than propagating a single conditional distribution as does conventional Bayesian estimation, a convex set of conditional distributions is evolved. For linear Gaussian systems, the convex set can be generated by a set of Gaussian distributions with equal covariance with means in a convex region of state space. The conventional point-valued Kalman filter is generated to a set-valued Kalman filter consisting of equations of evolution of a convex set of conditional means and a conditional covariance. The resulting estimator is an exact solution …

Ccfss News February 1991, Wei-Wen Yu Center For Cold-Formed Steel Structures

CCFSS Newsletters (1999 - 2008)

No abstract provided.

The Optimal Location Of Geodss Sensors In Canada, Pierre J. Forgues

Theses and Dissertations

This thesis studies the maximal coverage p-median and the set covering facility location problems as applied to the GEODSS location problem. The classical single-objective mathematical formulations of the p-median and set covering problems are converted into network-flow formulations and various solution methods are developed using a scaled-down version of the GEODSS problem. The next step is the introduction of a second criterion function into the problem. This second function consists of minimizing the sum of the variance in coverage at the selected locations. Research reveals the deficiencies of MOLP (multiobjective linear programming) techniques in generating the efficient frontier of an …

Quantum Network Theory Of Transport With Application To The Generalized Aharonov-Bohm Effect In Metals And Semiconductors, Cheng-Hsiao Wu, Gunter Mahler

Electrical and Computer Engineering Faculty Research & Creative Works

Quantum transport for resistor networks is developed with a general form factor, where each node point of the network is associated with a potential. The phase factor of the wave function in between two adjacent nodes is related to the reflection coefficient along that path. The exact transmission probability for a generalized Aharonov-Bohm ring is derived for a clean and cold crystal ring of arbitrary two-lead connections. The even- and odd-numbered rings have distinctly different transmission behaviors. The periodicity of the odd-numbered ring with respect to the threaded magnetic flux is shown to be double to that of an even-numbered …

A Combined Gel Entrapped And Membrane Attached Microbial Process For Biodegrading Organic Compounds, Fayaz Saifuddin Lakhwala

Dissertations

A comparative study has been performed between two bioreactors treating phenol, one using calcium alginate entrapped microorganisms, and the other using microorganisms attached on the surface of a polymeric membrane. Laboratory experiments conducted in batch recirculation mode, as well as a continuous feed mode, showed that the calcium alginate bio-bead reactor is more efficient in treating high feed concentrations of phenol, while the membrane bioreactor is more effective in the lower concentration regime (less than 150 ppm). In batch recirculation mode, the reaction rates (expressed as mg phenol/hr*gm dry cells) in the membrane reactor are an order of magnitude higher …

Thermodynamics Of Strong Electrolyte Solutions : Prediction Of Osmotic Coefficients By Pair Correlation Function Method, One Kwon Rim

Dissertations

Thermodynamic properties (osmotic coefficients) of strong electrolyte solutions have been studied by the method of statistical mechanics. First the charged soft sphere potential is developed based on the Pauling type model. Next the charged soft sphere potential is converted to the thermodynamically corresponding charged hard sphere potential by way of the perturbation method developed by Verlet and Weis. Simultaneously, the radial distribution function is developed by modification of the Exponential theory through introduction of the Stillinger-Lovett moment condition. The effective hard sphere diameter values calculated by the perturbation method are combined with the modified Exponential theory, and these quantities are …

On Local Stresses And Spring Constants Of A Sphere-Nozzle Connection, Ban-Li Lyow

Dissertations

This dissertation studies the local stresses and spring constants of a spherical shell with a nozzle attachment when it is under various loadings, namely radial force, overturning moment, horizontal shear force, and torsional moment. Because of the mathematical difficulty in modeling the nozzle-sphere configuration, particularly with nozzle opening, the finite element method (ANSYS package) is utilized in this study. The model used in this study is a quadrilateral thin shell element model when the γ_s (spherical radius/thickness) value is larger than 10. Otherwise the isoparametric solid element is used. The resulting stresses are basically biaxial state of stresses. It …

Direct Schottky Injection Image Sensors, Subramanyam V. Ayyagari

Theses

This thesis describes the analysis and simulations of Direct Schottky Injection (DSI) imagers which have 100% fill factor. Frame transfer (FT) and interline transfer (IT) DSI imager structures have been investigated. Theoretical Poisson solution for the PT and P-NP FT-DSI structures is presented, which closely agrees with simulation results. Simulation for frame transfer FT-DSI imagers has been done in SUPREM III since 1-D effects are more dominant. Single carrier transit time for both the structures were estimated from the electric fields.

Simulations of IT-DSI structures was done using PISCES llb, to get the local electric fields, which define the directionality …

Multiresolution Techniques : Laplacian Pyramid Coding And Its Comparison With Subband Coding, Danmei Chang

Theses

The multiresolution pyramid and related structures have been developed as intermediate representations between the purely frequency domain and purely spatial domain. In this thesis. we discuss two important pyramid structures which are often used in multiresolution representation: Laplacian pyramid and subband coding.

Laplacian pyramid. a typical pyramid structure, is studied in detail. By means of software implementation. we obtain a comprehensive understanding of its features and applications in image representation and data compression. Several modifications of pyramid structure are used to compress the data dynamic range, reduce the computational complexity and improve performance. Performance of the conventional Laplacian pyramid and …

Centrifugal Modeling Of Leaking Underground Storage Tanks, Kuo-Neng George Chang

Theses

There are between 2 to 3.5 million Underground Storage Tanks (UST) located through this nation. Most of these tanks store gasoline and fuel oil. Many tanks in fact are or will soon be leaking, thus making them one of the major sources of groundwater contamination in USA. The fate and transport of chemicals from the leaking USTs is estimated from mathematical models. A major difficulty in these modeling efforts has been a crucial lack of information concerning the constitutive relationships governing multiphase contaminant movement.

Centrifugal modeling is an alternative to mathematical modeling, which may give an insight to the problem …

Fast Packet Switching For B-Isdn With Neural Net Control, Ajit K. Chaudhuri

Theses

The concept of integrated network where both the voice packet and data packet are delt with, started taking shape since 1970. Later, Users? demand for communication of data, voice, file, facsimile, image, videotext, videophone, videomovie has also been felt. All these services need bit rate of transmission in the order of 10, even 100 Mbits. An economical way to transmit this higher bit rate, with flexibility of bandwidth, is to treat voice/video in the form of packets and transmit those packets in real time. Studies of this kind of communication is carried out in Broadband ISDN ( BISDN). At this …

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

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

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.

Development Of Techniques Of Artificial Intelligence In Identifying The Different Machined Surfaces, Yi-Ching Chou

Theses

This thesis deals with the identification of different machined surfaces with artificial inteligence techniques. There are five kinds of machining operations: grinding, turning, milling, EDM and waterjet which determine the characteristics of resulting surfaces. Topology of various specimens is measured using the surfanylizer. Twenty one parameters are extracted from the measurements to describe the characteristics. In this thesis, we develop neural and expert systems that recoginize and classify surfaces according to the machining methods.

Information Handling System With A Personal Computer To Assist In The Manufacturing Of Plastic Parts, Yi Chung

Theses

The ongoing personal computer development has led to its increasing application in manufacturing to improve productivity. Being more aware of this technology, most of these benefits have accrued to large firms. The intent of this thesis is to show that it is equally advantageous for small manufacturing companies to utilize them and show how they can do so.

The field of production control systems is discussed and those areas where personal computers can be applied are emphasized. Forecasting, warehouse management, material requirement planning, and inventory control are the most appropriate. An application example using dBase III plus to write the …

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

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

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 …

Some Aspects Of Integration Of Classification, Computer Aided Design, Process Planning, And Scheduling Of Flexible Manufacturing Systems, Suresh Godavari

Theses

This work deals with the role, problems and solution technique for integration of Computer Assisted Design, Classification, Process Planning, and Scheduling for a Flexible Manufacturing System. A lark spectrum of rotational and prismatic parts are considered.

A Knowledge-based rough classification and coding system [C&C] has been developed for coding similar parts using a Group Technology [GT] technique. In this module VP-EXPERT and DBase III Plus are used as expert system and database respectively. This module interfaces with a database for the retrieval and selection process.

The code obtained from the C&C system is the basis for the succeeding phases. The …

Deposition Of Particles In A Channel With Gravity And Image Forces, Jing-Shiun Lai

Theses

Deposition of particles in a parallel-plate channel under the influence of inertia, fluid viscosity, gravity and image forces was studied using trajectory method.

A laminar fluid flow of uniform and parabolic (or fully-developed) velocity profiles is assumed and the fluid is suspended with particles having the same velocity as the fluid at the inlet plane. The particles flowing into a horizontal parallel-plate channel have no initial velocity in the vertical direction. The influence of gravity force and image force produces a vertical motion which results in deposition of particles on the channel walls.

A trajectory method was employed to find …

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

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

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

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

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

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 …