Engineering Commons^™

Onset Of Tethered Chain Overcrowding, William Y. Chen, Joseph X. Zheng, Stephen Z. D. Cheng, Christopher Y. Li, Ping Huang, Huiming Xiong, Qing Ge, Ya Guo, Roderic P. Quirk, Bernard Lotz, Lingfeng Deng, Chi Wu, Edwin L. Thomas

College of Polymer Science and Polymer Engineering

We proposed an approach to precisely control the density of tethered chains on solid substrates using PEO-b-PS and PLLA-b-PS. As the crystallization temperature T-x increased, the PEO or PLLA lamellar crystal thickness d(L) increased as well as the reduced tethering density (σ) over tilde of the PS chains. The onset of tethered PS chains overcrowding in solution occurs at (σ) over tilde*similar to3.7-3.8 as evidenced by an abrupt change in the slope between (d(L))(-1) and T-x. This results from the extra surface free energy created by the tethered chain that starts to affect the growth barrier of the crystalline blocks.

Architectures For Symbol Timing Synchronization In Mimo Communications, Kejing Liu

Theses and Dissertations

Maximum likelihood symbol timing estimation for communication over a frequency non-selective MIMO fading channel is developed. The cases of known data (data-aided estimation) and unknown data (non-data-aided estimation) together with known channel and unknown channel are considered. The analysis shows that the log-likelihood functions and their approximations can be interpreted as SISO log-likelihood functions operating on each of the receive antennas. Previously published symbol timing estimators are shown to be special cases of the more general framework presented. Architectures based on both block processing and sequential processing using a discrete-time phase-locked loop are summarized. Performance examples over a MIMO channel …

Consensus Seeking, Formation Keeping, And Trajectory Tracking In Multiple Vehicle Cooperative Control, Wei Ren

Theses and Dissertations

Cooperative control problems for multiple vehicle systems can be categorized as either formation control problems with applications to mobile robots, unmanned air vehicles, autonomous underwater vehicles, satellites, aircraft, spacecraft, and automated highway systems, or non-formation control problems such as task assignment, cooperative transport, cooperative role assignment, air traffic control, cooperative timing, and cooperative search. The cooperative control of multiple vehicle systems poses significant theoretical and practical challenges. For cooperative control strategies to be successful, numerous issues must be addressed. We consider three important and correlated issues: consensus seeking, formation keeping, and trajectory tracking. For consensus seeking, we investigate algorithms and …

Flexible Machine Tool Control For Direct, In-Process Dimensional Part Inspection, Tyler Addison Davis

Theses and Dissertations

For some time now coordinate measuring machines have been an integral part of the shop floor. The goal has been to make coordinate measuring machines (CMMs) into tools that can easily be used by machinists to improve their manufacturing capabilities. The value of a CMM as a quality control tool is undisputed. Now efforts are being made to further reduce the time and cost of measurement by reducing the physical distance between machining and measuring processes. The ability to reduce that distance to zero and measure a part directly on the chip-making machine has been a goal for many years. …

Wideband Channel Characterization For Mimo Scenario, Justin T. Holzer

Theses and Dissertations

Because broadband wireless systems benefit from accurate channel characterization, there is growing interest in broadband wireless multiple-input multiple-output (MIMO) channel models. This thesis verifies the suitability of the Saleh Valenzuela with Angle (SVA) model for wideband MIMO communication models. While recent wideband MIMO measurements have been obtained by switching a single transmit/receive pair over all possible antenna pair combinations, a simultaneous probing system is superior because of the time required for the antenna-switching channel measurements. This work provides two different wideband channel estimation algorithms based on simultaneous transmission from and reception on all antennas. Simulated data from an electromagnetic ray …

Incentive Auctions And Stable Marriages Problems Solved With Bn=2c-Privacy Of Human Preferences, Marius C. Silaghi

Electrical Engineering and Computer Science Faculty Publications

Incentive auctions let several participants to cooperate for clearing a set of offers and requests, ensuring that each participant cannot do better than by inputting his true utility. This increases the social welfare by efficient allocations, and is proven to have similar outcomes as the tradition English Auctions. The desk-mates (stable matchings) problem comes from the need of placing students in pairs of two for working in projects or seating in two-seats desks. The stable marriages problem consists of finding matches of a man and a woman out of two sets of men, respectively women. Each of the persons in …

Visual Impact Of The Illuminations Of Lcd Monitor Under Different Ambient Lightings, Yuichi Yuasa

Graduate Research Papers

As criticisms about the eyestrain of computer monitor are increased, the interaction between human and VDTs has been examined. The studies of visual performance of LCD monitor are emphasized with numerous advantages. This study investigated the differences of visual comfort among three levels of illumination of an LCD monitor and ambient lighting. A statis ti cal experience was conducted concerning the procedure ofISO's recommendations with sample participants in the selected area. After the analysis of the data using ANOVA, the result showed the statistically significant difference and significant interaction between two variables. The combination between both medium ambient lighting and …

Environment-Induced Degradation And Crack-Growth Studies Of Candidate Target Materials: Annual Progress Report (May 2003 – May 2004), Ajit K. Roy

Transmutation Sciences Materials (TRP)

As indicated in the original proposal, the primary objective of this task was to evaluate the effect of hydrogen on environment-assisted cracking of candidate target structural materials for applications in spallation-neutron-target (SNT) systems such as accelerator production of tritium (APT) and accelerator transmutation of waste (ATW). The materials selected for evaluation and characterization were martensitic stainless steels including Alloy EP 823, HT-9, and Type 422 stainless steel. The susceptibility to stress corrosion cracking (SCC) of these materials were evaluated in neutral and acidic aqueous environments using smooth and notched tensile specimens under constant-load (CL) and slow-strain-rate (SSR) conditions. Further, the …

Motion Compensation Of Interferometric Synthetic Aperture Radar, David P. Duncan

Theses and Dissertations

Deviations from a nominal, straight-line flight path of a synthetic aperture radar (SAR) lead to inaccurate and defocused radar images. This thesis is an investigation into the improvement of the motion compensation algorithm created for the BYU inteferometric synthetic aperture radar, YINSAR. The existing BYU SAR processing algorithm produces improved radar imagery but does not fully account for variations in attitude (roll, pitch, yaw) and does not function well with large position deviations. Results in this thesis demonstrate that a higher order motion compensation algorithm is not as effective as using a segmented reference track, coupled with the current lower-order …

A Framework For Trajectory Based Visual Event Retrieval, Ilker Ersoy, Filiz Bunyak, S. R. Subramanya

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a framework of a system for the query and retrieval of video data based on video events in huge video repositories. the events are formulated using domain-independent event primitives which are represented by spatio-temporal relationships between objects in the video scenes. Complex events are expressible as combinations of simpler events. This facilitates support of event queries from a variety of points of view. in addition, the framework is expected to provide adaptability of the framework to multiple domains.

Performance Evaluation Of Block-Based Motion Estimation Algorithms And Distortion Measures, S. R. Subramanya, Hiral Patel, Ilker Ersoy

Electrical and Computer Engineering Faculty Research & Creative Works

Motion estimation is an important component in video compression schemes which impacts the encoder performance and the quality of the reconstructed video sequence. Block-Based techniques are the most popular among the several motion estimation techniques used in practice due to their simplicity allowing efficient hardware implementations. the quality of motion predicted frame and the speed of motion vector computation are the primary measures of performance of motion estimation schemes. the video compression standards only specify the syntax of the bitstream and not any specifics of the motion estimation techniques. Thus, the knowledge of the workings and performance of commonly used …

Admittance Selection For Force-Guided Assembly Of Polyhedral Parts In Single-Point Contact, Shuguang Huang, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

The selection of the proper admittance is important in achieving force-guided assembly. This paper identifies procedures for selecting the appropriate spatial admittance to achieve reliable force-guided assembly of polyhedral parts for single-point frictionless contact cases. Sets of conditions that are imposed on the admittance matrix for different types of single-point contact are presented. These conditions ensure that the motion that results from contact reduces part misalignment in the selected contact state. We show that, for bounded misalignments, if an admittance satisfies the misalignment-reduction conditions at a finite number of contact configurations, then the admittance also satisfy the conditions at all …

A Suite Of Secure Multi-Party Computation Algorithms For Solving Distributed Constraint Satisfaction And Optimization Problems, Marius C. Silaghi

Electrical Engineering and Computer Science Faculty Publications

Privacy requirements can be modeled within the distributed constraint satisfaction framework, where the constraints are secrets of the participants. In [20] we introduced a first technique allowing agents to solve distributed constraint problems (DisCSPs), without revealing anything and without trusting each other or some server. The first technique we propose now, MPC-DisCSP2, is a dm times improvement for m variables of domain size d. A second technique we propose, MPC-DisCSP3, has a similar complexity as MPD-DisCSP2, a little slower in the worst case, but guarantees that the returned solutions are picked according to a uniform distribution over the total set …

Pressure Distribution Around Spherical Distal Ball-Tip In Ultrasound Angioplasty, Graham Gavin, Garrett B. Mcguinness, Finbar Dolan, M.S. J. Hashmi

Conference Papers

INTRODUCTION Ultrasound Angioplasty has been shown to be effective in the removal and re-canalising of blockages in arteries (Siegel RJ, 1993). By delivering therapeutic ultrasound to the blockage, via a wire waveguide to a ball-tip, the lesion or thrombus is affected by pressure waves, micro streaming, cavitation and direct contact with the oscillating ball-tip. Most work to date has concentrated on a spherical ball-tip geometry at the distal end of the wire waveguide (Steffen, 1994 and Rosenschein, 1996). Tip displacements usually lie between 10 - 100m (peak-to peak) and ball tip diameters between 1 - 2mm (Atar, 1999 and Yock, …

Predicting Traffic Crashes Using Real-Time Traffic Speed Patterns, Mohamed Abdel-Aty, Anurag Pande

Civil and Environmental Engineering

Despite of the recent advances in traffic surveillance technology and ever-growing concern over traffic safety, there have been very few research efforts establishing Jinks between the real-time traffic flow parameters and crash occurrence. This study aims at the identification of the patterns in the freeway loop detector data, which potentially precede traffic crashes. This would have impOltant implications for Advanced Traffic Management Centers (ATMC). ATMCs could then be able to predict the potential for crashes on freeways and take action to reduce this hazard by warning drivers or introducing variable speed limits. Solution approach to this research problem essentially involves …

Flexible Roofing Facility: 2003 Summer Test Results, Florida Solar Energy Center, Danny Parker

FSEC Energy Research Center®

The Flexible Roof Facility (FRF) is a test facility in Cocoa, Florida designed to evaluate five roofing systems at a time against a control roof with black shingles and vented attic (Figure E-1). The testing evaluates how roofing systems impact summer residential cooling energy use and peak demand. In the summer of 2003, the following roofing systems were tested: Galvalume® unfinished 5-vee metal with vented attic (2nd year of exposure); sealed attic with proprietary configuration; high reflectance brown metal shingle with vented attic; galvanized unfinished 5-vee metal with vented attic (2nd year of exposure); black shingles with standard attic ventilation …

Beyond Convex? Global Optimization Is Feasible Only For Convex Objective Functions: A Theorem, R. Baker Kearfott, Vladik Kreinovich

Departmental Technical Reports (CS)

It is known that there are feasible algorithms for minimizing convex functions, and that for general functions, global minimization is a difficult (NP-hard) problem. It is reasonable to ask whether there exists a class of functions that is larger than the class of all convex functions for which we can still solve the corresponding minimization problems feasibly. In this paper, we prove, in essence, that no such more general class exists. In other words, we prove that global optimization is always feasible only for convex objective functions.

Optimal Finite Characterization Of Linear Problems With Inexact Data, Vladik Kreinovich

Departmental Technical Reports (CS)

For many linear problems, in order to check whether a certain property is true for all matrices A from an interval matrix [A], it is sufficient to check this property for finitely many "vertex" matrices. J. Rohn has discovered that we do not need to use all 2^(n^2) vertex matrices, it is sufficient to only check these properties for 2^(2n-1)<<2^(n^2) vertex matrices of a special type A_{yz}. In this paper, we show that a further reduction is impossible: without checking all 2^(2n-1) matrices A_{yz}, we cannot guarantee that the desired property holds for all A from [A]. Thus, these special vertex matrices provide an optimal finite characterization of linear problems with inexact data.

Outlier Detection Under Interval Uncertainty: Algorithmic Solvability And Computational Complexity, Vladik Kreinovich, Luc Longpre, Praveen Patangay, Scott Ferson, Lev Ginzburg

Departmental Technical Reports (CS)

In many application areas, it is important to detect outliers. Traditional engineering approach to outlier detection is that we start with some "normal" values x1,...,xn, compute the sample average E, the sample standard variation sigma, and then mark a value x as an outlier if x is outside the k0-sigma interval [E-k0*sigma,E+k0*sigma] (for some pre-selected parameter k0). In real life, we often have only interval ranges [xi] for the normal values x1,...,xn. In this case, we only have intervals of possible values for the bounds E-k0*sigma and E+k0*sigma. We can therefore identify outliers as values that are outside all k0-sigma …

Towards Combining Probabilistic And Interval Uncertainty In Engineering Calculations, Scott A. Starks, Vladik Kreinovich, Luc Longpre, Martine Ceberio, Gang Xiang, Roberto Araiza, J. Beck, R. Kandathi, A. Nayak, R. Torres

Departmental Technical Reports (CS)

In many engineering applications, we have to combine probabilistic and interval errors. For example, in environmental analysis, we observe a pollution level x(t) in a lake at different moments of time t, and we would like to estimate standard statistical characteristics such as mean, variance, autocorrelation, correlation with other measurements. In environmental measurements, we often only know the values with interval uncertainty. We must therefore modify the existing statistical algorithms to process such interval data. Such modification are described in this paper.

Computing 2-Step Predictions For Interval-Valued Finite Stationary Markov Chains, Marcilia Andrade Campos, Gracaliz Pereira Dimuro, Antonio Carlos Da Rocha Costa, Vladik Kreinovich

Departmental Technical Reports (CS)

Markov chains are a useful tool for solving practical problems. In many real-life situations, we do not know the exact values of initial and transition probabilities; instead, we only know the intervals of possible values of these probabilities. Such interval-valued Markov chains were considered and analyzed by I. O. Kozine and L. V. Utkin in their Reliable Computing paper. In their paper, they propose an efficient algorithm for computing interval-valued probabilities of the future states. For the general case of non-stationary Markov chains, their algorithm leads to the exact intervals for the probabilities of future states.

In the important case …

Fabrication, Characterization, And Modeling Of Organic Capacitors, Schottky Diodes, And Field Effect Transistors, Mo Zhu

Doctoral Dissertations

The objectives of this project are to fabricate, characterize, and model organic microelectronic devices by traditional lithography techniques and Technology Computer Aided Design (TCAD).

Organic microelectronics is becoming a promising field due to its number of advantages in low-cost fabrication for large area substrates. There have been growing studies in organic electronics and optoelectronics. In this project, several organic microelectronic devices are studied with the aid of experimentation and numerical modeling.

Organic metal-insulator-metal (MIM) and metal-insulator-semiconductor (MIS) capacitors consisting of insulating polymer poly(4-vinylphenol) (PVP) have been fabricated by spin-coating, photo lithography, and reactive ion etching techniques. Based on the fabricated …

Development And Calibration Of A Large-Scale Thermal Conductivity Probe, James L. Hanson, Stefan Neuhaeuser, Nazli Yesiller

Civil and Environmental Engineering

A large-scale probe has been developed for measuring the thermal conductivity of geomaterials. The large probe was designed to conduct tests on materials containing large particles, materials with high heterogeneity, and materials with high stiffness. The probe has dimensions of 680 mm length and 15.9 mm diameter and was constructed of stainless steel tubing. The probe operates on the principle of heating an infinite line source in an infinite medium. Initially, parametric evaluations were conducted to determine the operational and test conditions for the large probe, including power level, heating duration, and zone of heating influence. Then, tests were conducted …

Identification Of Hysteretic Systems With Slip Using Bootstrap Filter, S. J. Li, Yoshiyuki Suzuki, Mohammad N. Noori

Office of the Dean (CENG) Scholarship

Hysteretic models with slip are frequently used to predict the non-linear behaviour of many structural systems, for example wood buildings and reinforced concrete structures. A model, called SL model, which can describe the pinching of most practical hysteresis loops perfectly was proposed by Baber and Noori. This model is characterised by control parameters that have to be identified from observed experimental data. A method of estimating the parameters of SL model on the basis of input–output data based on Bayesian state estimation and bootstrap filter is suggested in this paper, which has the great advantages of being able to handle …

Santa Clara Magazine, Volume 46 Number 1, Summer 2004, Santa Clara University

Santa Clara Magazine

8 - A PUZZLING PROFESSOR By Adam Breen. Byron Walden, an assistant professor of mathematics at SCU, draws on his knowledge of numerical analysis to create crossword puzzles for The New York Times.

10 - THE LAUNCHING PAD By Larry Sokoloff J.D. '92. Top government agencies, other universities, and companies are relying on the University's Robotics Systems Lab-and its students-to build and monitor satellites.

16 - A NOVEL TEAM By Kristin Lenore '04. The University's publishing partnership with Heyday Books aims to help preserve California's cultural legacy.

The Effect Of Transition Metal Additions On The Microstructure And Properties Of Nanocomposite Pr–Fe–B Permanent Magnets, Jeffrey E. Shield, Yi Liu, R. Marr, Z. Chen, Baomin Ma

Materials Research Science and Engineering Center: Faculty Publications

Permanent magnets with the general composition Pr₉ (Fe_0.95Co_0.05)_85.5M_0.5B₅, where M denotes a transition metal, have been produced by melt spinning. The effect on the microstructure and magnetic properties of eight different alloying elements has been examined. The grain size and distribution have been correlated to the maximum energy product obtained. The grain size of the Pr₉ (Fe_0.95Co_0.05) _85.5B₅ control alloy was determined to be 17.5 nm, and it was found that the grain size was not significantly reduced compared to the control …

Domain-Wall Pinning At Inhomogenities Of Arbitrary Cross-Sectional Geometry, Ralph Skomski, Jian Zhou, Arti Kashyap, David J. Sellmyer

Materials Research Science and Engineering Center: Faculty Publications

Abstract—The coercivity of cellular Sm-Co based permanent magnets is investigated by model calculations. The grain boundaries responsible for the pinning coercivity are modeled as planar inhomogenities with arbitrary cross-sectional geometry. The calculation yields a physically transparent integral equation for the pinning energy, whose derivative is the pinning force. The theory rationalizes experimental data on a semiquantitative level, but without adjustable parameters, and bridges the gap between smooth concentration gradients and abrupt interfaces. Explicit results are obtained for sinoidal profiles, for very thin grain boundaries, and for profiles intermediate between attractive and repulsive pinning. The corrections predicted by the present model …

Magnetization Reversal And Giant Coercivity In Sm-Co/Cu-Ti Particulate Films, Jian Zhou, Arti Kashyap, Yi Liu, Ralph Skomski, David J. Sellmyer

Materials Research Science and Engineering Center: Faculty Publications

Highly coercive granular SmCo/CuTi films were produced by thermal processing of sputtered SmCo₅ (CuTi) multilayers and investigated experimentally and theoretically. Electron microscopy shows that the processed films consist of spherical grains that have diameters of 5–10 nm and are embedded in a matrix. Both the grains and the matrix phase exhibit the CaCu₅ structure, but the matrix is probably Cu-rich. The films have high coercivities of up to 50.4 kOe at 300 K. Analytical calculations and micromagnetic simulations yield a transition from a nucleation-type weak-interaction regime to a discrete-pinning-type strong-interaction regime. The transition occurs at packing fractions similar …

A High -Order Finite Difference Method For Solving Bioheat Transfer Equations In Three-Dimensional Triple -Layered Skin Structure, Haofeng Yu

Doctoral Dissertations

Investigations on instantaneous skin burns are useful for an accurate assessment of burn-evaluation and for establishing thermal protections for various purposes. Meanwhile, hyperthermia with radiation is important in the treatment of cancer, and it is essential for developers and users of hyperthermia systems to predict, and interpret correctly the biomass thermal and vascular response to heating. In this dissertation, we employ the well-known Pennes' bioheat transfer equation to predict the degree of skin burn and the temperature distribution in hyperthermia cancer treatment.

A fourth-order compact finite difference scheme is developed to solve Pennes' bioheat transfer equation in a three-dimensional single …

Robust Image Transmission Based On Wavelet Tree Coding, Error Resilient Entropy Coding, And Error Concealment, Lei Cao, Chang Wen Chen

Electrical Engineering and Computer Science Faculty Publications

A scheme with three key components including wavelet tree coding, error resilient entropy coding (EREC), and error concealment is proposed for robust image coding and transmission over noisy channels. First, we individually encode the spatial-orientation trees in the wavelet domain using the algorithm of set partitioning in hierarchical trees (SPIHT). Error propagation is thus limited because multiple independent bit streams are generated. Meanwhile, a high source coding efficiency is also preserved because the self-similarity property in each wavelet tree remains intact. Next, we use EREC to reorganize these variable-length bit streams into fixed-length data slots before multiplexing and transmission. Therefore, …