Engineering Commons^™

The Impact Of Communication Medium On Team Performance Patterns, Pilar Pazos, Mario G. Beruvides

Engineering Management & Systems Engineering Faculty Publications

The increased impact of globalization and rapidly changing technologies are some of the biggest challenges facing 21st century organizations. Remote teams supported through computer-based systems have been identified as a key lever to help organizations adapt to this turbulent environment. This study sheds some light on how teams perform and adapt by evaluating performance and synergy over time for teams in two different settings: computer supported and face-to-face. Participants in the study were randomly assigned either to a computer-supported or a face-to face group. Each group met over three sessions to perform a series of tasks that were evaluated using …

Unified Large And Small Signal State-Space Based Modeling And Symbolic Simulation For Pwm Converters, Ehab Shoubaki

Electronic Theses and Dissertations

In this Dissertation, which concentrates on discrete modeling for control purposes of DC/DC converters and simulation through symbolic techniques. A Unified Discrete State-Space Model for power converters in CCM is presented. Two main approaches to arriving at the discrete model are used. The first approach involves an impulse function approximation of the duty cycle modulation of the converter switches, and this approach results in a small signal discrete model. The Second approach is direct and does not involve any approximation of the modulation, this approach yields both a large signal nonlinear discrete model and a linear small signal model. Harmonic …

The Calibration, Validation, And Comparison Of Vissim Simulations Using The Two-Fluid Model, Jeremy Crowe

Electronic Theses and Dissertations

The microscopic traffic simulation program VISSIM is a powerful tool that has been used by transportation engineers and urban planners around the world. A VISSIM simulation is meant to depict the performance of the physical road network through the use of modeling tools and behavioral parameters. The process which gets the model to the point of matching real world conditions is called calibration and requires a means of relating the real world to the simulated world. The topic of this thesis discusses a new means of calibration using the two-fluid model. The two-fluid model is a macroscopic modeling technique which …

Presence-Dependent Performance Differences Between Virtual Simulations And Miniature Worlds, Andre Huthmann

Electronic Theses and Dissertations

The purpose of simulation is to avoid reality-based constraints by the implemen-tation of a synthetic model. Based on this advantage, interactive simulations have conquered all areas of applications from acquisition, and training, to research. Simulation results are transferred in many ways into reality and conclusions are drawn from the simulation to the application. Many anecdotal observations on human-in-the-loop simulations have shown a significant difference in actor behavior between simulations and reality-based applications. It seems that the factors that makes simulation so attractive, namely the absence of constraints and especially of imminent danger for persons and equipment, influence the behavior and …

Sensitivity Analysis Framework For Large And Complex Simulation Models, Ghaith Rabadi, Shannon Bowling, Charles Keating, Resit Unal

Engineering Management & Systems Engineering Faculty Publications

In this paper, a framework for conducting Sensitivity Analysis (SA) on large and complex simulation models is introduced. The framework consists of components that are designed to make the SA a systematic process that is easy to manage and follow by simulation analysts and practitioners. Unlike local SA (one-variable-at-a-time SA), the method presented here is variance-based and it is rooted in the field of Design of Experiments (DoE) where Input Variables are varied and Output Variables are measured. Based on the DoE results, a risk scoring system is developed to identify the sensitivity of the Input Variables, and as a …

Simulation Of A Tubular Solid Oxide Fuel Cell Stack Operating On Biomass Syn-Gas Using Aspen Plus, Wayne Doherty, Anthony Reynolds, David Kennedy

Articles

A tubular solid oxide fuel cell (SOFC) stack is modelled and its operation on biomass syn-gas is investigated. The objective of this work is to develop a computer simulation model of a biomass gasification-SOFC (BG-SOFC) system capable of predicting performance under various operating conditions and using diverse fuels. The stack is modelled using Aspen Plus and considers ohmic, activation and concentration losses. It is validated against published data for operation on natural gas. Operating parameters such as fuel and air utilisation factor (U_f and U_a), current density (j) and steam to carbon ratio ( …

Highway Bridge Assessment For Dynamic Interaction With Critical Vehicles, Daniel Cantero, Eugene J. Obrien, Arturo González, Bernard Enright, Cillian Rowley

Conference papers

Dynamic vehicle-bridge interaction is often considered for the most common classes of vehicle such as the 5-axle articulated truck. However, the dynamic response of bridges to this type of trucks is quite different to the response to the vehicles more likely to feature in maximum-in-lifetime traffic loading events. This paper focuses on large (>100 tonne) cranes and crane-type vehicles that have been recorded at Weigh-in-Motion sites in Europe. This paper analyses the total bending moment due to these vehicles on short to medium span bridges and compare them to 5- axle articulated trucks. To account for the variability in …

Dod Acquisition Workforce Education: An Sba Education Case Study, Richard Davenport

Electronic Theses and Dissertations

A Department of Defense (DoD) M&S education task force is in the process of studying the Modeling and Simulation (M&S) education of the acquisition workforce. Historically, DoD acquisition workforce education is not referred to as education, but rather what the Defense Acquisition University (DAU) refers to as "practitioner training, career management, and services." The DAU is the organization primarily responsible for training the DoD acquisition corps in conjunction with service schools and strategic partners in the civilian sector. DAU programs primarily focus on program management, contracting, and management of logistics across the system life cycle. Further, the examples and cases …

Safety And Operational Evaluation Of Dynamic Lane Merging In Work Zones, Rami Harb

Electronic Theses and Dissertations

Traffic safety and mobility of roadway work zones have been considered to be one of the major concerns in highway traffic safety and operations in Florida. In intent to expose Florida's work zones crash characteristics, the Florida Traffic Crash Records Database for years 2002, 2003 and 2004 were explored. Statistical models were estimated and Florida's work zone crash traits for single vehicle crashes and two-vehicle crashes were drawn. For the single-vehicle crashes, trucks were found more likely to be involved in single vehicle crashes in freeway work zones compared to freeways without work zones. Straight level roadways are significantly affected …

Passenger Car Equivalents Of Trucks Under Lane Restriction And Differential Speed Limit Policies On Four Lane Freeways, John Stanley

LSU Master's Theses

Lane restriction for trucks and differential speed limits for trucks and cars are becoming more common and feasible policies to improve the efficiency and safety of a freeway. It is believed that passenger car equivalents for trucks are impacted by these non typical freeway operating conditions, which are not explicitly addressed by the latest edition of the Highway Capacity Manual. Using simulated and real world data an elevated 18- mile four lane freeway was modeled under the restriction policies. The section which was used as a test bed was simulated under various control variables. Some of the control variables used …

High Voltage Dc Converter Systems Modeling, Simulation And Analysis, Manish A. Dalal

Browse all Theses and Dissertations

The thesis provides insights into important modeling techniques to model the converter system, machine design, control and power stages and integration of the various sub systems to simulate the system level performance. This innovative modeling and simulation project is very relevant to optimizing the system performance, designing the sub circuits, components selection, predicting the system stability and impulse responses. The thesis presents modeling and simulation of three different 270VDC converter systems and comparing their performances against each other. The 270VDC converter system accepts either Generator 3-phase AC voltages or fixed three voltage source followed by single or dual converter stages …

Formal Verification Of Urban Traffic System Using The Concept Of Fuzzy Workflow Simulation, Manuj Darbari, Abhay Kumar Srivastava, Sanjay Medhavi

Journal of International Technology and Information Management

Modeling complex urban traffic system requires extensive use of workflow methodologies which can simulate almost real time traffic situations. Number of studies were done in the field of Urban Traffic Simulation like PLOTS, NETSIM and PALAMICS but none of them could provide a real formal solution. Our paper proposes a methodology using Fuzzy Petri nets for modeling real time traffic system. Fuzzy Petrinets are also visualised and tested by using Flow- Charter and HPSIM software packages. These packages help in providing successive iterations of process model for further refinement.

Photocatalytic Reaction In Monolithic Optical Fiber Reactor With Inverse Opal Catalyst, Maoming Ren

LSU Doctoral Dissertations

The development of photocatalytic reactor is essential for the successful application of heterogeneous semiconductor in environmental study, which has been shown to be photoactive and effective to oxidate organic pollutant and photoreduce CO2 to useful compounds. In this dissertation, a monolithic optical fiber reactor (MOFR) coated with inverse opal titania, which uses optical fibers as light-transmitting conductor and support of catalyst, was developed for both photodegradation and photoreduction. 1,2-dichlorobenzene, a volatile organic compound (VOC), was selected as the organic pollutant. This configuration of reactor and catalyst provides a high surface area, enhances mass transfer within the catalyst, manipulates photons transmission …

Simulation Of Nanostructured Electrodes For Polymer Electrolyte Membrane Fuel Cells, Sanjeev M. Rao, Yangchuan Xing

Chemical and Biochemical Engineering Faculty Research & Creative Works

Aligned carbon nanotubes (CNTs) with Pt uniformly deposited on them are being considered in fabricating the catalyst layer of polymer electrolyte membrane (PEM) fuel cell electrodes. When coated with a proton conducting polymer (e.g., Nafion) on the Pt/CNTs, each Pt/CNT acts as a nanoelectrode and a collection of such nanoelectrodes constitutes the proposed nanostructured electrodes. Computer modeling was performed for the cathode side, in which both multicomponent and Knudsen diffusion were taken into account. the effect of the nanoelectrode lengths was also studied with catalyst layer thicknesses of 2, 4, 6, and 10 μm. It was observed that shorter lengths …

Dynamic Analysis Of Less-Than-Truckload Shipments And Test Method To Simulate This Environment, Sher Paul Singh, E. Joneson, Jay Singh, G. Grewal

Industrial Technology and Packaging

This paper provides results from a comprehensive data measurement study that analyzed the vibration dynamics produced inside the trailers used for less-than truckload (LTL) shipments. The trailers used for this segment of the package transportation environment are very different in size and suspension than those used for full truckload shipments. This study measured the vertical, lateral and longitudinal vibration inside a trailer as a function of road surface. In addition, the study developed a video showing freight movement inside the trailer to determine physical displacement and shifting of the loads. A set of recommendations was developed to safely load and …

An Engineering Evaluation Of Ankle Prosthetics, Christopher Thian, Stephen Tiernan, Fiona Mcevoy, Robert Flavin

Conference Papers

There are a wide range of different types of ankle replacements on the market today each with a
different mechanical design. Unfortunately the results of ankle replacements are not as good as hip
and knee replacements; this is due to the complexity of the ankle joint. In the early days of ankle
replacements some of the prosthetics only lasted 4 months. Recent developments have improved the
longevity of the replacements although, there are still many complications and failures of the
replacements, these include; the prosthetic components migrating into the bone, the components
failing due to stresses induced by the forces …

Modeling Systems For Optimal Resource Allocation, Scheduling, And Decision Making, Esengul Tayfur

All Dissertations

This dissertation focuses on the resource requirements and scheduling problem for logistic systems. We investigate solutions to this problem in two different logistic systems: logistic system of the health care facilities during emergency evacuations and delivery and distribution system of production industries. All hospitals must have an evacuation plan to ensure the safety of patients and prevent the loss of life. However, hospital operators have not been able to quantify how resource availability, the cost of acquiring those resources, and evacuation completion time are related. This research addresses this problem and contributes two methodologies to solve this problem. In the …

A Real-Time Traffic Condition Assessment And Prediction Framework Using Vehicle-Infrastructure Integration (Vii) With Computational Intelligence, Yongchang Ma

All Dissertations

This research developed a real-time traffic condition assessment and prediction framework using Vehicle-Infrastructure Integration (VII) with computational intelligence to improve the existing traffic surveillance system. Due to the prohibited expenses and complexity involved for the field experiment of such a system, this study adopted state-of-the-art simulation tools as an efficient alternative.
This work developed an integrated traffic and communication simulation platform to facilitate the design and evaluation of a wide range of online traffic surveillance and management system in both traffic and communication domain. Using the integrated simulator, the author evaluated the performance of different combination of communication medium and …

An Open Framework For Highly Concurrent Real-Time Hardware-In-The-Loop Simulation, Ryan C. Underwood, Bruce M. Mcmillin, Mariesa Crow

Computer Science Faculty Research & Creative Works

Hardware-in-the-loop (HIL) real-time simulation is becoming a significant tool in prototyping complex, highly available systems. The HIL approach permits testing of hardware prototypes of components that would be extremely costly or difficult to test in the deployed environment. In power system simulation, key issues are the ability to wrap the systems of equations (such as Partial Differential Equations) describing the deployed environment into real-time software models, provide low synchronization overhead between the hardware and software, and reduce reliance on proprietary platforms. This paper introduces an open source HIL simulation framework that can be ported to any standard Unix-like system on …

Using Agile Software Development Practices In A Research Oriented Distributed Simulation, Douglas James Mielke

Computational Modeling & Simulation Engineering Theses & Dissertations

Although sometimes controversial, agile methodologies have proven to be a viable choice for some software development projects. Projects suited to agile methodologies are those that involve new technology, have requirements that change rapidly, and are controlled by small, talented teams. Much literature about agile software development leans towards business products and non-government entities. Only a handful of literature resources mention agile software development being used in government contracts and even fewer resources mention research projects. NASA's Airspace and Traffic Operations Simulation (ATOS) is a research oriented simulation that doesn't follow the traditional business project mold. In an effort to gain …

Equivalent Barge And Flotilla Impact Forces On Bridge Piers, Peng Yuan, Issam E. Harik

Kentucky Transportation Center Research Report

Bridge piers located in navigable inland waterways are designed to resist impact forces from barges and flotillas in addition to other design considerations (e.g., scour, dead and live loads, etc.). The primary design tool for estimating these forces is the AASHTO Guide Specification which provides a simple hand calculation method for determining an “equivalent impact force”. The simplicity comes at a cost of excluding the effect of the pier shape, impact duration, and interaction between barges in a flotilla. The objective of this report is to present a hand calculation method for determining barge or flotilla equivalent static impact forces …

Multi-Barge Flotilla Impact Forces On Bridges, Peng Yuan, Issam E. Harik, Michael T. Davidson

Kentucky Transportation Center Research Report

The current AASHTO equations for barge impact loads are based on scale models of barges, and may not accurately predict impact loads on bridge piers. The results of this study produce more realistic flotilla impact design loads, potentially leading to a reduction in construction costs of bridges over navigable waterways. The objectives of this study are: (1) To conduct theoretical finite element analysis on various types of flotillas impacting bridge piers. The flotillas and the respective barges will be of the type commonly traversing Kentucky’s waterways; and (2) To generate design equations for barge/flotilla impact loads. The study concludes the …

Performance Study Of Mpls And Ds Techniques To Improve Qos Routing For Critical Applications On Ip Networks, Salim Alsharif, Mohammad Mehdi Shahsavari

Electrical Engineering and Computer Science Faculty Publications

This paper aims to analyze the QoS performance of two main technology mechanisms, Multi-Protocol Label Switching (MPLS) and Differentiated Services (DS). The introduction of both mechanisms to support throughput and delay sensitive real-time media traffic will have an impact on critical applications with respect to QoS and traffic engineering. MPLS is a traffic forwarding mechanism that allows traffic to use multiple paths and DS is a mechanism that provides for aggregate traffic to be classified and conditioned at the edge of the network routers. The two modeled techniques and their performance will be evaluated with respect to their end-to-end delay. …

Simulation Of A Circulating Fluidised Bed Biomass Gasifier Using Aspen Plus: A Performance Analysis, Wayne Doherty, Anthony Reynolds, David Kennedy

Conference Papers

In the near future biomass gasification is likely to play an important role in energy production and conversion. Its application has great potential in the context of climate change mitigation, increasing efficiency and energy security. Atmospheric circulating fluidised bed (CFB) technology was selected for the current study. An original computer simulation model of a CFB biomass gasifier was developed using ASPEN Plus (Advanced System for Process ENgineering Plus). It is based on Gibbs free energy minimisation and the restricted equilibrium method was used to calibrate it against experimental data. This was achieved by specifying the temperature approach for the gasification …

Agent-Based Modeling And Possible Implications On Management And Engineering Management, Ipek Bozkurt, Jose J. Padilla, Andres A. Sousa-Poza

VMASC Publications

Engineering Management (EM) is a discipline that takes pride in bridging two major fields, namely engineering and management. It is clear from any basic research conducted within this field that both engineering and management tools and paradigms need to be used jointly. A mixture that encompasses quantitative and qualitative research, as well as theoretical and empirical research is found in literature, making Engineering Management, as a discipline, very complex in nature. As this complexity evolves, so should the tools of the craft. It is interesting, however, to see that Agent-Based Modeling (ABM) as a tool or as a topic of …

Implementation Of Simulation For Network Service Delivery Point Capacity Analysis, Tiffany Jill Harper

Browse all Theses and Dissertations

As businesses consolidate and modernize their operations, the impact on their network and computing infrastructure is a major consideration. In this thesis, discrete event simulation is used to show how implementation of an Enterprise Resource Planning (ERP) system can impact network performance and ultimately affect end-users. More specifically, the model simulates the flow of data packets across a network, through a Service Delivery Point (SDP), which is comprised of routers, switches, and firewalls that connect a Local Area Network to a Wide Area Network.

The model was used to run to determine the affect of more network traffic and additional …

Simulation And Fabrication Of Three Novel Micromechanical Sensors, Yanqing Lu

Doctoral Dissertations

This work focuses on the simulation, fabrication and characterization of novel microdevices for chemical and biological sensors for improved sensitivity, enhanced performance and applicability. Specifically, microbridge and microcoil sensors have been fabricated via advanced microfabrication technologies. Due to the potential application in chemical and biological sensing, the growth of gold and platinum nanowires during an electrolysis process have also been investigated.

A microbridge can be considered as the head-to-head fusion of two cantilevers and the middle of the bridge would deform in a way similar to a microcantilever. The microbridge sensing device is more stable than the microcantilever, especially in …

Computer-Based Instruction For Engineering Education In The Developing World, Bradford G. Singley

Theses and Dissertations

Although civil engineers continually develop new ways to solve problems involving water, energy, infrastructure and environmental sustainability, these innovations can take years – or even decades – to reach developing countries. Computer-based instruction has the potential to dramatically decrease this lag time by improving engineering education in the developing world. This paper discusses the development of instructional simulations, based on the theory of model-centered instruction. These simulations can serve as self-paced learning modules, which can be accessed for free over the Internet. A pilot learning module was developed for the United Nations Educational Scientific and Cultural Organization (UNESCO) on the …

Steer It And Clear It: Effectiveness Of Quick Clearance Legislation, Amy Carol Hamlin

All Theses

Innovative incident management strategies have been sought by transportation professionals to minimize the impacts of incidents on traffic operation and safety. Some current quick clearance strategies such as 'Steer It and Clear It' legislation in South Carolina, which requires driver(s) of involved vehicle(s) in a minor incident to move vehicles promptly from the traveled roadway prior to the arrival of the first responders, can potentially reduce the duration of an incident. The research detailed in this paper endeavored to measure the benefit of the Steer It and Clear It law on a section of I-85 in South Carolina. A simulation …

A New Method For Treating Wells In Reservoir Simulation, Gregory M. Gessel

Theses and Dissertations

A new method for formulating finite difference equations for reservoir simulation has been developed. It can be applied throughout the entire simulated reservoir or to local segments. When applied to cells containing vertical, fully penetrating, straight-line wells in a homogeneous reservoir, the resulting equations are equivalent to Peaceman's classical well equations used in most reservoir simulators today. However, when the new finite difference equations are applied to both the well-containing cells, and their neighbors, the accuracy of the simulation improves substantially. The method produces still better accuracy results when applied throughout the reservoir. Unlike the Peaceman correction, the new method …