Engineering Commons^™

Effect Of Intermittent Applications Of Continuous Ultrasound Signal On The Morphology And Cytoskeletal Organization In Chondrocytes, Anuradha Subramanian, Sandra Noriega, Gulnara Hasanova

Anuradha Subramanian Publications

The cellular component of the articular cartilage, chondrocytes, have long been recognized as strain-sensitive cells, and have the ability to sense mechanical stimulation through surface receptors and intracellular signaling pathways. In the present study, a continuous ultrasound wave for predetermined time intervals was employed, as opposed to pulsed-ultrasound used in previous studies, to stimulate chondrocytes seeded in 3D scaffolds. Chondrocytes seeded in 3D scaffolds (n = 6) were subjected to stimulation by US as follows: 1.5 MHz for 161 s, 5.0 MHz for 51 s and 8.5 MHz for 24 s and the US signal was applied twice in a …

Control On Platelet Adhesion And Activation Events By Selective And Specific Binding Of Plasma Protein On Peptide-Coupled Surface, Anuradha Subramanian, Sanjukta Guha-Thankruta

Anuradha Subramanian Publications

Implantable material surfaces suffer from unavoidable major events of blood–biomaterial interactions leading to thrombus formation and finally foreign material rejection. An albuminated surface can minimize the platelet adhesion and activation that reduces the chance of thrombus formation. The main objective of our work was to design surfaces having maximum human serum albumin (HSA) binding capacity over other plasma proteins in blood by covalently grafting custom made peptides having selectivity and specificity towards HSA. First, silicon wafer surfaces were chemically treated to generate –NH2 terminated self-assembled monolayer (SAM). SAMs were then covalently coupled with (a) peptides using 1- ethyl-3-[3-dimethylaminopropyl]carbodiimide hydrochloride and …

Importance Of Annealing Times In The Pcr Amplification Of Gc-Rich Genes, Anuradha Subramanian, Tarlan Mamedov, Elsje Pinnear, Hendrik J. Viljoen

Anuradha Subramanian Publications

This combined theoretical and experimental study conclusively demonstrates that annealing times play a crucial role in the PCR amplification of GC-rich templates. To assist with the DNA amplification of GC-rich targets, a theory has been developed that evaluates the fraction of annealed primer/polymerase complex at the correct binding site as a function of annealing temperature and annealing period. Optimum annealing times lie in the range of 3 to 6 s, and annealing times greater than 10 s yield smeared PCR amplified products. The theory has been applied to the PCR amplification of the following human cDNA templates: ARX gene (78.2%, …

Ultraviolet And Pulsed Electric Field Treatments Have Additive Effect On Inactivation Of E. Coli In Apple Juice, T. K. Gachovska, Saurabh Kumar, Harshanardhan Thippareddi, F. Williams

P. F. (Paul Frazer) Williams Publications

Apple juice inoculated with Escherichia coli ATCC 23472 was processed continuously using either ultraviolet (UV), high-voltage pulsed electric field (PEF), or a combination of the PEF and UV treatment systems. Apple juice was pumped through either of the systems at 3 flow rates (8, 14, and 20 mL/min). E. coli was reduced by 3.46 log CFU/mL when exposed in a 50 cm length of UV treatment chamber at 8 mL/min (2.94 s treatment time with a product temperature increase of 13 °C). E. coli inactivation of 4.87 log CFU/mL was achieved with a peak electric field strength of 60 kV/cm …

Temperature (5.6-300k) Dependence Comparison Of Carrier Transport Mechanisms In Hfo2/Sio2 And Sio2 Mos Gate Stacks, Richard G. Southwick Iii, Justin Reed, Christopher Buu, Hieu Bui, Ross Butler, G. Bersuker, William B. Knowlton

Electrical and Computer Engineering Faculty Publications and Presentations

Temperature dependent measurements have been used to examine transport mechanisms and energy band structure in MOS devices. In this study, a comparison between high-k HfO₂ dielectrics and conventional SiO₂ dielectrics is made to investigate dielectric specific thermally activated mechanisms. Temperature dependent measurements on large area n/pMOSFETs composed of SiO₂ and HfO₂/SiO₂ gate dielectrics were performed from 5.6 K to 300 K. A large increase in the gate leakage current is observed at the formation of the minority carrier channel. The data indicate that gate leakage current prior to the formation of the minority channel …

Extension Of Viscoplasticity Based On Overstress To Capture The Effects Of Prior Aging On The Time Dependent Deformation Behavior Of A High-Temperature Polymer: Experiments And Modeling, Amber J. W. Mcclung

Theses and Dissertations

The inelastic deformation behavior of PMR-15 neat resin, a high-temperature thermoset polymer, was investigated at 288 degrees C. The experimental program was designed to explore the influence of strain rate on tensile loading, unloading, and strain recovery behaviors. In addition, the effect of the prior strain rate on the relaxation response of the material, as well as on the creep behavior following strain controlled loading were examined. The experimental data were modeled with the Viscoplasticity Based on Overstress (VBO) theory. A systematic procedure for determining model parameters was developed and the model was employed to predict the response of the …

Microstructure Analysis Of Aluminum Alloy And Copper Alloy Circular Shells After Multiaxial Plastic Buckling, N. Drusina, R. Mahapatra, A. Abdul-Latif, R. Baleh, C. Wilhelm, P. Stoyanov, Omar S. Es-Said

Mechanical Engineering Faculty Works

Aluminum and copper cylindrical shells were plastically buckled under quasi-static and dynamic loading conditions with an Absorption Compression-Torsion Plasticity (ACTP: Patent No. WO 2005090822) combined mechanical testing device. Optical microscopy and transmission electron microscopy (TEM) analysis were used to study the microscopic evolutions in the mechanically buckled aluminum and copper alloy samples. Optical microscopy showed evidence of the presence of second-phase particles in both the aluminum and copper alloys samples. Under dynamic loading aluminum samples showed more energy absorption as compared to copper samples. Material flow lines were more pronounced in the copper samples when observed by optical microscopy. The …

Impact Of Vegetable Oil On Distribution Of Trichloroethylene In Groundwater During Enhanced Bioremediation, M. Pu, Ryan Dupont, William J. Doucette

Civil and Environmental Engineering Faculty Publications

Vegetable oils are increasingly being used as long-term carbon donors to stimulate reductive dechlorination of trichloroethylene (TCE). Besides potential enhancement of biodegradation, the addition of vegetables oils may impact TCE fate and distribution within the aquifer by acting as non-aqueous phase liquids (NAPL). Distribution coefficients for TCE between groundwater and four vegetable oils were determined using a slow-stir technique. Log vegetable oil/water distribution coefficients (log Kvw) were found to range from 1.0 to 2.56. TCE/vegetable oil distribution coefficients statistically increased with an increase in oil weathering while the concentration of dissolved organic carbon (DOC) in the water did not change …

Fusing Semantics, Observability, Reliability And Diversity Of Concept Detectors For Video Search, Xiao-Yong Wei, Chong-Wah Ngo

Research Collection School Of Computing and Information Systems

Effective utilization of semantic concept detectors for large-scale video search has recently become a topic of intensive studies. One of main challenges is the selection and fusion of appropriate detectors, which considers not only semantics but also the reliability of detectors, observability and diversity of detectors in target video domains. In this paper, we present a novel fusion technique which considers different aspects of detectors for query answering. In addition to utilizing detectors for bridging the semantic gap of user queries and multimedia data, we also address the issue of "observability gap" among detectors which could not be directly inferred …

Modeling Video Hyperlinks With Hypergraph For Web Video Reranking, Hung-Khoon Tan, Chong-Wah Ngo, Xiao Wu

Research Collection School Of Computing and Information Systems

In this paper, we investigate a novel approach of exploiting visual-duplicates for web video reranking using hypergraph. Current graph-based reranking approaches consider mainly the pair-wise linking of keyframes and ignore reliability issues that are inherent in such representation. We exploit higher order relation to overcome the issues of missing links in visual-duplicate keyframes and in addition identify the latent relationships among keyframes. Based on hypergraph, we consider two groups of video threads: visual near-duplicate threads and story threads, to hyperlink web videos and describe the higher order information existing in video content. To facilitate reranking using random walk algorithm, the …

Window Queries Over Data Streams, Jin Li

Dissertations and Theses

Evaluating queries over data streams has become an appealing way to support various stream-processing applications. Window queries are commonly used in many stream applications. In a window query, certain query operators, especially blocking operators and stateful operators, appear in their windowed versions. Previous research work in evaluating window queries typically requires ordered streams and this order requirement limits the implementations of window operators and also carries performance penalties. This thesis presents efficient and flexible algorithms for evaluating window queries. We first present a new data model for streams, progressing streams, that separates stream progress from physical-arrival order. Then, we …

Estimation Of Hurricane Winds From Seawinds At Ultrahigh Resolution, David G. Long, Brent A. Williams

Faculty Publications

Although the SeaWinds scatterometer was not specifically designed to observe tropical cyclones, new high-resolution wind products resolve much of the horizontal structure of these storms. However, these higher resolution products (2.5 km) are inherently noisier than the standard 25-km near-surface wind products. These noise levels combined with rain contamination complicate high-resolution wind estimation-particularly in tropical cyclones. Fortunately, tropical cyclones have structures that can be exploited by using a wind field model. This paper develops a new procedure for hurricane wind field estimation from the SeaWinds instrument at ultrahigh resolution. A simplified hurricane model is developed to provide prior information to …

Reduced-Feedback Linear Precoding With Stable Performance For The Time-Varying Mimo Broadcast Channel, Michael A. Jensen, Adam L. Anderson, James R. Zeidler

Faculty Publications

This work explores the performance of a multiple-input multiple-output broadcast channel where both the transmitter and receivers have outdated channel knowledge due to node motion or other time-variations in the communication channel. A performance analysis based on measured channel responses reveals significant throughput degradation for optimal linear and nonlinear precoding strategies unless the channel state information (CSI) is frequently fed back to the transmitter. The paper then develops a linear beamforming precoding strategy based on channel distribution information in the form of a full spatial correlation matrix for each user. This algorithm is shown to provide highly stable communication, with …

Determining The Number Of Bp Neural Network Hidden Layer Units, Huayu Shen, Zhaoxia Wang, Chengyao Gao, Juan Qin, Fubin Yao, Wei Xu

Research Collection School Of Computing and Information Systems

This paper proposed an improved method to contrapose the problem which is difficult to determine the number of BP neural network hidden layer units. it is proved that the method is efficeient in reducing the frequency of the test through experients, and improves the efficiency of determining the best number of hidden units, which is more valuable in the applications.

Ontology-Based Visual Word Matching For Near-Duplicate Retrieval, Yu-Gang Jiang, Chong-Wah Ngo

Research Collection School Of Computing and Information Systems

This paper proposes a novel approach to exploit the ontological relationship of visual words by linguistic reasoning. A visual word ontology is constructed to facilitate the rigorous evaluation of linguistic similarity across visual words. The linguistic similarity measurement enables cross-bin matching of visual words, compromising the effectiveness and speed of conventional keypoint matching and bag-of-word approaches. A constraint EMD is proposed and experimented to efficiently match visual words. Empirical findings indicate that the proposed approach offers satisfactory performance to near-duplicate retrieval, while still enjoying the merit of speed efficiency compared with other techniques.

A Low-Cost Open-Hardware Wideband Multiple-Input-Multiple-Output (Mimo) Wireless Channel Sounder, Michael A. Jensen, Jon W. Wallace, B. T. Maharaj, Louis P. Linde

Faculty Publications

Due to the complexity of multiple-input-multiple- output (MIMO) wireless channels, direct measurement is the main viable option for accurate characterization. Details on a new low-cost wideband channel sounder are presented, which was mainly constructed from conventional instruments and components. This switched architecture system is similar to commercial channel sounders and has modest cost (< US$ 50000). The sounder operates in the 2- to 8-GHz range with up to 100 MHz of instantaneous bandwidth and supports eight transmitters and receivers, which are sufficient to support the development and assessment of current and future MIMO wireless systems. In this "open-hardware" project, the hardware design and software components are openly available to other researchers interested in developing or enhancing the MIMO measurement capability. The actual systems built at the University of Pretoria, Pretoria, South Africa, and Brigham Young University, Provo, UT, are presented, as are some example studies.

Optimal Estimation Of Calibration Parameters In Polarimetric Microwave Radiometers, David G. Long, Derek Hudson

Faculty Publications

Methods for internal calibration of a certain class of microwave polarimetric radiometers are presented by Piepmeier. In that work, the calibration parameters are estimated algebraically. We demonstrate that Bayesian estimation decreases the root-mean-square error of the estimates by a factor of two. This improvement is obtained by using knowledge of the noise structure of the measurements and by utilizing all of the information provided by the measurements. Drawbacks are the increased complexity of the method and an increase in computation. We also extend the method to estimate several hardware component parameters of interest in system calibration.

Theory And Application Of Motion Compensation For Lfm-Cw Sar, David G. Long, Evan C. Zaugg

Faculty Publications

Small low-cost high-resolution synthetic aperture radar (SAR) systems are made possible by using a linear frequency-modulated continuous-wave (LFM-CW) signal. SAR processing assumes that the sensor is moving in a straight line at a constant speed, but in actuality, an unmanned aerial vehicle (UAV) or airplane will often significantly deviate from this ideal. This nonideal motion can seriously degrade the SAR image quality. In a continuous-wave system, this motion happens during the radar pulse, which means that existing motion compensation techniques that approximate the position as constant over a pulse are limited for LFM-CW SAR. Small aircraft and UAVs are particularly …

Spreadsheet Data Resampling For Monte-Carlo Simulation, Thin Yin Leong, Wee Leong Lee

Research Collection School Of Computing and Information Systems

The pervasiveness of spreadsheets software resulted in its increased application as a simulation tool for business analysis. Random values generation supporting such evaluations using spreadsheets are simple and yet powerful. However, the typical approach to Monte-Carlo simulations, which is what simulations with stochasticity are called, requires significant amount of time to be spent on data collection, data collation, and distribution function fitting. In fact, the latter can be overwhelming for undergraduate students to learn and do properly in a short time. Resampling eliminates both the need to fit distributions to the sample data, and to perform the ensuing tests of …

Engineering Management Framework In Support Of Modeling & Simulation Application For Domain Specific Procurement, Thomas Guy Litwin

Engineering Management & Systems Engineering Theses & Dissertations

A strategic process is desirable for project-based organizations in order for them to be efficient and effective when developing Modeling & Simulation (M&S) systems. This thesis proposes an overarching process that combines traditional M&S and Engineering Management methodologies in a new framework to support M&S organizations during the procurement process.

This thesis proposes both a Strategic Project Management Process (SPMP) and a systems engineering process for M&S federation development projects. The systems engineering process utilizes the artifacts of Model Driven Architecture (MDA) to support building M&S federations driven by operational requirements. Detailed research of this systems engineering process revealed a …

Education Enhancement Using Visualization And Simulation Tools For Basic Circuit Theory Concepts, Jariwala Rajvi Prakashchandra

Electrical & Computer Engineering Theses & Dissertations

New generation web-technologies and supporting development tools have prompted opportunities for developing new methods of teaching and learning. Web-based visualization and simulation modules developed for ODU's ECE201 Circuit Theory course are presented in this thesis. Visualization and simulation methodology is used to make learning process more interactive and effective. Macromedia FLASH software, which has the extensive graphical animation capabilities, is used to develop visualization modules. Lab VIEW is a leading graphical development tool for science and engineering with a built-in functionality for simulation, data acquisition, instrument control, measurement analysis and data presentation. These capabilities are utilized to develop web-based simulation …

The Development Of Genetic Algorithm For The Prediction Of Ship Motion From Wave Radar Data, Sumanth Tirumala Vangipuram

Electrical & Computer Engineering Theses & Dissertations

Genetic Algorithms represent a model of natural process based on the Darwinian principle of evolution. Genetic algorithms are used to solve optimization problems by generating a set of possible solutions and determining which of these solutions most closely match the desired result. The Genetic Algorithm (GA) initially generates a random set of possible solutions, or populations, determines which members of the population are most desirable, and calculates better solutions by implementing genetic operations such as reproduction, cloning, and mutation. Problems where the evaluation of a solution is computationally simple enable the GA to search a vast search space. One of …

Using Timed-Release Cryptography To Mitigate Preservation Risk Of Embargo Periods, Rabia Haq

Computer Science Theses & Dissertations

This research defines Time-Locked Embargo, a framework designed to mitigate the Preservation Risk Interval: the preservation risk associated with embargoed scholarly material. Due to temporary access restrictions, embargoed data cannot be distributed freely and thus preserved via data refreshing during the embargo time interval. A solution to mitigate the risk of data loss has been developed by suggesting a data dissemination framework that allows data refreshing of encrypted instances of embargoed content in an open, unrestricted scholarly community. This framework has been developed by exploiting implementations of existing technologies to"time-lock" data using Timed-Release Cryptology (TRC) so that it can be …

An Agent-Based Combat Simulation Framework In Support Of Effect-Based And Net-Centric Evaluation, Robert Joseph Bowen

Computational Modeling & Simulation Engineering Theses & Dissertations

The use of information technologies (IT) and information networks has proliferated in industry as a method to achieve competitive advantage. The U.S. Military and its allies, in recent years, have employed IT to improve the way they conduct operations, speed decision making, and increase the span of control of commanders. This has resulted in a fundamental shift in the way military commanders employ combat units today. These (Information Age) forces no longer have to be able to see each other or even communicate directly in order to synchronize maneuvers. Dispersion is now favored over mass, relying on the IT network …

Computational Solution Of Tail Buffet Response And Active Flow Control, Kaushik Laxmikant Joshi

Mechanical & Aerospace Engineering Theses & Dissertations

In this thesis, numerical simulation of the multidisciplinary method for prediction and control of vortex induced tail buffeting is studied using delta wing-single tail configuration. Flow conditions are chosen such that wing vortex cores experience vortex breakdown and the resulting wake flow impinges on the vertical tail. The aero/structure problem is solved sequentially using three sets of equations on a multi-block grid structure. To obtain aerodynamic loading on the tail, the fluid flow around the wing-tail assembly is computed by time-accurately solving unsteady, laminar, compressible Navier-Stokes equations using an implicit, upwind, flux-difference splitting finite volume scheme. Then the aeroelastic equations …

Chain-Type Wireless Sensor Network For Monitoring Long Range Infrastructures: Architecture And Protocols, Chang Wen Chen, Yu Wang

Electrical Engineering and Computer Science Faculty Publications

We present in this paper an investigation of a special class of wireless sensor networks for monitoring critical infrastructures that may extend for hundreds of miles in distances. Such networks are fundamentally different from traditional sensor networks in that the sensor nodes in this class of networks are deployed along narrowly elongated geographical areas and form a chain-type topology. Based on careful analysis of existing sensor network architectures, we first demonstrate the need to develop new architecture and networking protocols to match the unique topology of chain-type sensor networks. We then propose hierarchical network architecture that consists of clusters of …

Canonical Correlation Feature Selection For Sensors With Overlapping Bands: Theory And Application, Biliana S. Paskaleva, Majeed M. Hayat, Zhipeng Wang, J. Scott Tyo, Sanjay Krishna

Electrical and Computer Engineering Faculty Research and Publications

The main focus of this paper is a rigorous development and validation of a novel canonical correlation feature- selection (CCFS) algorithm that is particularly well suited for spectral sensors with overlapping and noisy bands. The proposed approach combines a generalized canonical correlation analysis framework and a minimum mean-square-error criterion for the selection of feature subspaces. The latter induces ranking of the best linear combinations of the noisy overlapping bands and, in doing so, guarantees a minimal generalized distance between the centers of classes and their respective reconstructions in the space spanned by sensor bands. To demonstrate the efficacy and the …

Design And Implementation Of Mobile Free Space Optical Communication System, Xiaomin Jin, Xian Wang, Chi Yeh Hsu

Electrical Engineering

No abstract provided.

A Pressure Sensing System Using Fiber Optic Sensors And Artificial Neural Networks, Xiaomin Jin, Xiao-Hua Yu, Saied Zarger, Roshan H. Patel, Sam Wards

Electrical Engineering

No abstract provided.

A Sawtooth Waveform Inspired Pitch Estimator For Speech And Music, Arturo Camacho, John G. Harris

Electrical and Computer Engineering Faculty Research & Creative Works

A sawtooth waveform inspired pitch estimator (SWIPE) has been developed for speech and music. SWIPE estimates the pitch as the fundamental frequency of the sawtooth waveform whose spectrum best matches the spectrum of the input signal. The comparison of the spectra is done by computing a normalized inner product between the spectrum of the signal and a modified cosine. The size of the analysis window is chosen appropriately to make the width of the main lobes of the spectrum match the width of the positive lobes of the cosine. SWIPE′, a variation of SWIPE, utilizes only the first and prime …