Digital Commons Network^™

Capacity Of Single-Radio Ad Hoc Networks For Handling High Bit-Rate Real-Time Internet Applications, Mehran Abolhasan, Tadeusz A. Wysocki, Daniel Franklin, Justin Lipman

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

Until now, the main focus in ad hoc networking has been improving Routing and Medium Access Control (MAC) Strategies. As a result, a diverse range of routing and MAC protocols have been proposed. To evaluate these protocols, much of the existing research has been based on simulation scenarios which assume ideal channel conditions and low node and traffic densities. Therefore, despite a few studies which have shown the performance limitations of ad hoc networks theoretically, there has not been many simulation studies performed which investigate the performance of ad hoc networks under a high node and traffic density. This paper …

Direct Sequence Modified Time Hopping Ppm Over Ultra Wideband S-V Channel, Peter Vial, Beata J. Wysocki, Tadeusz A. Wysocki

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

A three position Pulse Position Modulation (PPM) scheme is proposed for a Direct Sequence Time Hopping Ultra Wideband wireless communication system. The channel is based on the Saleh-Valenzuela model. We show that by adapting the Space Time Spreading technique to use three pulse positions in a single input single output system representing -2,0,2 an improvement in Bit Error Rate is achieved compared to sending the same bits using two pulse positions only. In addition, the bit access rate is doubled as two bits can be successfully sent in the same time using our proposed system.

A Fuzzy Logic Controller For Autonomous Wheeled Vehicles, Mohamed Trabia, Linda Z. Shi, Neil Eugene Hodge

Mechanical Engineering Faculty Research

Autonomous vehicles have potential applications in many fields, such as replacing humans in hazardous environments, conducting military missions, and performing routine tasks for industry. Driving ground vehicles is an area where human performance has proven to be reliable. Drivers typically respond quickly to sudden changes in their environment. While other control techniques may be used to control a vehicle, fuzzy logic has certain advantages in this area; one of them is its ability to incorporate human knowledge and experience, via language, into relationships among the given quantities. Fuzzy logic controllers for autonomous vehicles have been successfully applied to address various …

Final Report: Westbrook Downtown Parking Study/Management Plan, Gorrill-Palmer Consulting Engineers, Inc.

Maine Town Documents

In the early 2000's, Westbrook was the beneficiary of an upswing in the Southern Maine economy, aided by a strong marketing effort on the part of the City. As a result, new office buildings and retail facilities located in or near the downtown area and older buildings were rehabilitated and redeveloped. This increase in commercial and business activity increased the demand for parking downtown. With an eye toward long-term growth, a parking management plan was developed to provide the tools necessary to manage the increased demand for parking.

Application Of Advanced Computational Modelling In The Numerical Prediction Of The Haemodynamic Impact Of Coronary Stent Implantation, Jonathan Murphy, Fergal Boyle

Conference Papers

Coronary stent implantation can improve blood flow in an artery narrowed by the build up of arterial plaque. However, the haemodynamic effect of stent placement is unclear and may influence arterial restenosis (re-blockage). In this investigation the stent induced, non-Newtonian blood flow disturbances have been captured in a three dimensional computational domain. The results clearly show areas of low wall shear stress proximal and distal to the stent wires, a characteristic which is known to encourage restenosis. Furthermore, this computational method of observing the complex haemodynamics of the stent environment can be used in conjunction with medical trial data to …

Solar Dhw Storage Tanks And Systems, Florida Solar Energy Center

FSEC Energy Research Center®

Water is by far the most common storage medium in solar domestic hot water systems. Rock storage is another method of sensible heat storage, but is not generally used in systems that are exclusively DHW. Storage of heat in solutions of phase-changing salts is extremely rare in DHVJ systems and therefore is not discussed.

Enhanced Criterion For Base Soil Retention In Embankment Dam Filters, Buddhima Indraratna, A. K. Raut

Faculty of Engineering - Papers (Archive)

In effective filters, potentially erodible base particles are transported to the filter and retained to form a stable self-filtration layer. At any given time, the mass proportion of the filter and the base materials in this layer depends on the initial porosity of the filter and the subsequent porosity of the self-filtration layer. In this paper, an analytical procedure is given to obtain the particle size distribution (PSD) of the self-filtration layer by combining the PSDs of the filter and the base soil modified by Dc95, where 95% of filter constrictions are finer than the size denoted by Dc95. The …

Laboratory Measurements Of Dynamic Properties Of Rail Pads Under Incremental Preload, Alexander Remennikov, Sakdirat Kaewunruen

Faculty of Engineering - Papers (Archive)

Rail pad is an important component in ballasted railway track. Its main function is to attenuate track loads, preventing underneath railway sleepers from excessive stress waves. Generally, the dynamic design of tracks relies on the available data that are mostly focused on the condition at a specific toe load. Recent findings show that track irregularities could significantly amplify the loads on railway tracks. This phenomenon gives rise to a concern that the rail pads may experience higher effective pre-loading than anticipated in the past. On this ground, this paper highlights the significance of accounting for effects of pre-loading on dynamic …

Impact Resistance Of Reinforced Concrete Columns: Experimental Studies And Design Considerations, Alexander Remennikov, Sakdirat Kaewunruen

Faculty of Engineering - Papers (Archive)

There are instances where reinforced concrete structures designed for static loads are subjected to accidental or deliberate impact or blast loads because of industrial or transportation accidents, military or terrorist activities. Analysis and design of structures for such events require realistic assessment of the ulti-mate impact resistance and a mode of failure of the structure. In this paper, a series of falling weight impact tests on conventionally designed reinforced concrete columns are described. The behaviour of quarter-scale reinforced concrete columns under static and impact loads is presented. An impact load was applied at the mid-height of the columns by a …

For Piecewise Smooth Signals, L1 Method Is The Best Among Lp: An Interval-Based Justification Of An Empirical Fact, Vladik Kreinovich, Arnold Neumaier

Departmental Technical Reports (CS)

Traditional engineering techniques use the Least Squares method (i.e., in mathematical terms, the l2-norm) to process data. It is known that in many practical situations, lp-methods with p=/=2 lead to better results. In different practical situations, different values of p are optimal. It is known that in several situations when we need to reconstruct a piecewise smooth signal, the empirically optimal value of p is close to 1. In this paper, we provide a new interval-based theoretical explanation for this empirical fact.

The Use Of Fast Integral Equations Solvers For Practical Package And Interconnect Analysis, J. D. Morsey, B. J. Rubin, L. (Lijun) Jiang, L. Shan, L. B. Eisenberg, D. Becker, M. Arseneault

Electrical and Computer Engineering Faculty Research & Creative Works

Fast integral equation methods are now being applied to packaging and other such "low frequency" problems. This paper explores some of the issues surrounding such an application to real, product level packaging and interconnect type structures. Discussed are issues such as low frequency breakdown, mesh aspect ratios, and solver convergence. Finally, integral equation solver examples are presented using the IBM internally developed pre-corrected FFT (PFFT) solver labeled EMSurf[l]. ©2006 IEEE.

Material Selection And Design Consideration For Moisture Damage Of Asphalt Pavement, Jamilla Emi Sudo Lutif, Yong-Rak Kim

Nebraska Department of Transportation: Research Reports

No abstract provided.

Information Infrastructure For Integrated Ecohydraulic And Water Resources Modeling And Assessment, R. Wallace, K. Pathak, M. Fife, Norman L. Jones, J. P. Holland, D. Stuart, J. Harris, C. Butler, D. R. Richards

Faculty Publications

Watershed management increasingly requires ecohydraulic modeling and assessment within a regional context, rather than on a project-by-project basis. Such holistic modeling and assessment require evaluation capabilities across multiple temporal and spatial scales. Thus, modeling and assessment tools must be integrated in a scientifically and computationally effective infrastructure. The US Army Engineer Research and Development Center, in concert with the Hydrologic Engineering Center and its academic partners, including Brigham Young University, is establishing a comprehensive set of hydroinformatics modeling and assessment tools for ecohydraulic and water resources management applications, all linked based on a common data and information infrastructure. This paper …

Interpretation Of Cone Penetration Tests In Cohesive Soils, Kwang Kyun Kim, Monica Prezzi, Rodrigo Salgado

JTRP Technical Reports

This report focuses on the evaluation of the factors affecting cone resistance measurement during cone penetration in saturated clayey soils and the application of the result to pile shaft capacity analysis. In particular, effects of drainage conditions around the cone tip were studied. Rate effects related to both drainage and shear strength dependence on loading rate were studied. In order to investigate the effects of drainage during penetration, penetration tests were performed with various velocities in the field and in a calibration chamber, and the obtained data were analyzed. For the field tests, two sites which have homogeneous clayey soil …

Ac Conductivity Relaxation Processes In Cacu₃Ti₄O₁₂ Ceramics: Grain Boundary And Domain Boundary Effects, Wei Li, Robert W. Schwartz

Materials Science and Engineering Faculty Research & Creative Works

The ac conductivity of CaCu₃Ti₄O₁₂ ceramics associated with electrical charge carrier motion (ions or vacancies) was investigated as a function of frequency at different temperatures. The long range migration of charge carriers within the ceramic is restricted by two kinds of insulating barriers, namely, grain boundaries and domain boundaries. The potential barriers associated with these boundaries lead to two anomalies in conductivity response and three frequency-dependent contributions to conductivity: long range diffusion of carriers, carrier migration localized within grains, and carrier migration localized within domains.

Cosign: A Parallel Algorithm For Coordinated Traffic Signal Control, Shih-Fen Cheng, Marina A. Epelman, Robert L. Smith

Research Collection School Of Computing and Information Systems

The problem of finding optimal coordinated signal timing plans for a large number of traffic signals is a challenging problem because of the exponential growth in the number of joint timing plans that need to be explored as the network size grows. In this paper, the game-theoretic paradigm of fictitious play to iteratively search for a coordinated signal timing plan is employed, which improves a system-wide performance criterion for a traffic network. The algorithm is robustly scalable to realistic-size networks modeled with high-fidelity simulations. Results of a case study for the city of Troy, MI, where there are 75 signalized …

Supply Chain Information Sharing In A Macro Prediction Market, Zhiling Guo, Fang Fang, Andrew B. Whinston

Research Collection School Of Computing and Information Systems

This paper aims to address supply chain partners' incentives for information sharing from an information systems design perspective. Specifically, we consider a supply chain characterized by N geographically distributed retailers who order a homogeneous product from one manufacturer. Each retailer's demand risk consists of two parts: a systematic risk part that affects all retailers and an idiosyncratic risk part that only has a local effect. We propose a macro prediction market to effectively elicit and aggregate useful information about systematic demand risk. We show that such information can be used to achieve accurate demand forecast sharing and better channel coordination …

A Simple Numerical Method Of Cycle Jumps For Cyclically Loaded Structures, D. Cojocaru, Anette M. Karlsson

Mechanical Engineering Faculty Publications

A method for accelerated numerical simulations of structures subjected to cyclic loading is investigated. Of particular interest is a class of structures where the structural properties evolve with time. The proposed method is based on conducting detailed finite element analysis for a set of cycles to establish a trend line, extrapolating the trend line spanning many cycles, and use the extrapolated state as initial state for additional FEA simulations. This includes a control function that automatically monitors the length of the cycle jump to ensure a realistic solution. We compare the proposed method to a reference calculation, where all incremental …

Multisensor Processing Algorithms For Underwater Dipole Localization And Tracking Using Mems Artificial Lateral-Line Sensors, Saunvit Pandya, Yingchen Yang, Douglas L. Jones, Jonathan Engel, Chang Liu

Mechanical Engineering Faculty Publications and Presentations

An engineered artificial lateral-line system has been recently developed, consisting of a 16-element array of finely spaced MEMS hot-wire flow sensors. This represents a new class of underwater flow sensing instruments and necessitates the development of rapid, efficient, and robust signal processing algorithms. In this paper, we report on the development and implementation of a set of algorithms that assist in the localization and tracking of vibrational dipole sources underwater. Using these algorithms, accurate tracking of the trajectory of a moving dipole source has been demonstrated successfully.

Distensibility Differs Between Sall Arteries And Veins In The Newborn Piglet Lung, John B. Gordon, Steven Thomas Haworth, Robert C. Molthen, Gary S. Krenz, Anne V. Clough

Biomedical Engineering Faculty Research and Publications

BACKGROUND: We previously used micro-CT techniques to measure pulmonary artery distensibility in 3 week old piglets. Pressure/diameter relationships were measured for each artery and the slope (a) was then plotted against its diameter intercept at 0 pressure (Do). The resultant diameter independent distensibility parameter, a, was estimated by linear regression to be 1.6% per mmHg for arteries between 0.2 and 3.0 mm Do.

OBJECTIVE: This study sought to determine whether; 1) distensibility of smaller arteries was similar to that of arteries with Do> 0.2 mm; and 2) whether small vein and artery distensibility was similar.

DESIGN/METHODS: Lower lobes were isolated …

Vision-Based Target Geo-Location Using A Fixed-Wing Miniature Air Vehicle, D. Blake Barber, Joshua D. Redding, Timothy W. Mclain, Randal W. Beard, Clark N. Taylor

Faculty Publications

This paper presents a method for determining the GPS location of a ground-based object when imaged from a fixed-wing miniature air vehicle (MAV). Using the pixel location of the target in an image, with measurements of MAV position and attitude, and camera pose angles, the target is localized in world coordinates. The main contribution of this paper is to present four techniques for reducing the localization error. In particular, we discuss RLS filtering, bias estimation, flight path selection, and wind estimation. The localization method has been implemented and flight tested on BYU’s MAV testbed and experimental results are presented demonstrating …

Novel Capacitance Extraction Method Using Direct Boundary Integral Equation Method And Hierarchical Approach, L. (Lijun) J. Jiang, B. J. Rubin, J. D. Morsey, H. T. Hu, A. Elfadel

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a novel hierarchical capacitance extraction method is introduced. It takes advantage of surface integral equations to have far less unknowns than the volumetric method. It uses the "divide and conquer" strategy to hierarchically solve the dense capacitance matrix efficiently. It partitions the problem into small regions (cells) automatically and each region is analyzed separately. An inverse binary-tree browse procedure is employed to combine cell capacitance matrixes from leafy level of the tree to the root. A global capacitance matrix is obtained at the root without computing charge distribution. Benchmarks using the developed code CSurf are provided to …

Dynamic Multi-Linked Negotiations In Multi-Echelon Production Scheduling Networks, Hoong Chuin Lau, Guan Li Soh, Wee Chong Wan

Research Collection School Of Computing and Information Systems

In this paper, we are concerned with scheduling resources in a multi-tier production/logistics system for multi-indenture goods. Unlike classical production scheduling problems, the problem we study is concerned with local utilities which are private. We present an agent model and investigate an efficient scheme for handling multi-linked agent negotiations. With this scheme we attempt to overcome the drawbacks of sequential negotiations and negotiation parameter settings. Our approach is based on embedding a credit-based negotiation protocol within a local search scheduling algorithm. We demonstrate the computational efficiency and effectiveness of the approach in solving a real-life dynamic production scheduling problem which …

Finding A Length-Constrained Maximum-Sum Or Maximum-Density Subtree And Its Application To Logistics, Hoong Chuin Lau, Trung Hieu Ngo, Bao Nguyen Nguyen

Research Collection School Of Computing and Information Systems

We study the problem of finding a length-constrained maximum-density path in a tree with weight and length on each edge. This problem was proposed in [R.R. Lin, W.H. Kuo, K.M. Chao, Finding a length-constrained maximum-density path in a tree, Journal of Combinatorial Optimization 9 (2005) 147–156] and solved in O(nU) time when the edge lengths are positive integers, where n is the number of nodes in the tree and U is the length upper bound of the path. We present an algorithm that runs in O(nlog2n) time for the generalized case when the edge lengths are positive real numbers, which …

Integral Equation Solvers For Real World Applications -Some Challenge Problems, W. C. Chew, I. T. Chiang, C. P. Davis, A. Hesford, M. K. Li, Y. Liu, Z. G. Qian, M. Saville, L. Sun, M. S. Tong, J. Xiong, L. (Lijun) J. Jiang, H. Y. Chao, Y. H. Chu

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

Numerical Analysis Of Sandwiched Composite-Fss Structures, Qiang Rui, Chen Ji, Huang Jingyu, Maria Koledintseva, Richard E. Dubroff, James L. Drewniak, Yang Fan

Electrical and Computer Engineering Faculty Research & Creative Works

A numerical technique to analyze shielding effectiveness of sandwiched FSS-composite structures is proposed. This technique is based on using a dispersive FDTD method in conjuncture with a novel periodic boundary condition to model sandwiched FSS-composite elements. Results show that by inserting single or multilayered FSS elements into composite materials, better shielding effectiveness can be achieved. © 2006 IEEE.

Effect Of Nb And C Additives On The Microstructures And Magnetic Properties Of Rapidly Solidified Sm-Co Alloys, S. Aich, Jeffrey E. Shield

Nebraska Center for Materials and Nanoscience: Faculty Publications

Highly coercive Sm-Co-based permanent magnets have been achieved through simple modification of binary Sm_{12Co88 alloys with Nb, C or combined Nb and C at concentrations ranging from 1 to 10 atomic percent processed via rapid solidification. Melt spinning at 40 m/s resulted in the formation of the metastable TbCu7-type structure in all alloys. While the unalloyed, as-solidified Sm12Co88 alloy displayed a coercivity of 0.5 kOe, alloying additions resulted in a systematic and profound increase in coercivity. Nb additions resulted in as-solidified coercivities up to 9 kOe, C additions up to 37 kOe, and combined NbC …}

Non-Destructive Testing (Ndt): A Tool For Dynamic Health Monitoring Of Railway Track Structures, Sakdirat Kaewunruen, Alexander Remennikov

Faculty of Engineering - Papers (Archive)

The applications of NDT are varied and recently, an NDT technique known as ‘modal analysis’ was adopted in railway engineering in order to measure track behaviours under either train services or man-made loadings. OVER THE PAST decade, modal testing has become an effective means for identifying, understanding, and simulating dynamic behaviour and responses of structures. One of the techniques widely used in modal analysis is based on an instrumented hammer impact excitation. By using signal analysis, the vibration response of the structures to the impact excitation is measured and transformed into frequency response functions (FRFs) using the Fast Fourier Transformation …

Field Monitoring And Computer Modeling To Determine Energy And Demand Savings From The Melink Intellihood Exhaust And Make-Up Air Control System At Two Supermarkets, One Restaurant, And One Fast Food Restaurant, Florida Solar Energy Center, James Cummings

FSEC Energy Research Center®

Note: Only the Executive Summary of this proprietary report is available for public download.

Florida Building Code - Enhance Florida's Building To Next-Generation Energy & Mechanical Codes And Enrich Compliance, Florida Solar Energy Center, Muthusamy V. Swami

FSEC Energy Research Center®

The project Implemented ASHRAE 90.1 2004 into Florida's compliance tool, EnergyGauge, to allow inclusion of the methodologies and rule sets of ASHRAE 90.1-2004. The project also implemented IECC 2003 into Florida's compliance tool to allow inclusion of the methodologies of Chapters 4, 5, and 6 of the International Energy Conservation Code 2003 (IECC 2003). Field testing was completed in 40 central Florida homes (built after March 1, 2002) to examine compliance with the balanced return air, duct leakage, and combustion/dilution air requirements of the Florida Mechanical Code. A course titled Complying with Duct System Requirements of the Florida Energy Code …