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Articles 3121 - 3150 of 4566

Full-Text Articles in Engineering

Lattice Vibration Study Of Silica Nanoparticle In Suspension, Parveen Sachdeva Jan 2006

Lattice Vibration Study Of Silica Nanoparticle In Suspension, Parveen Sachdeva

Electronic Theses and Dissertations

In recent years considerable research has been done in the area of "nanofluids". Nanofluids are colloidal suspensions of nanometer size metallic or oxide particles in a base fluid such as water, ethylene glycol. Nanofluids show enhanced heat transfer characteristics compared to the base fluid. The thermal transport properties of nanofluids depend on various parameters e.g. interfacial resistance, Brownian motion of particles, liquid layering at the solid-liquid interface and clustering of nanoparticles. In this work atomic scale simulation has been used to study possible mechanisms affecting the heat transfer characteristics of nanofluids. Molecular dynamics simulation for a single silica nanoparticle surrounded …

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Oscillatory Flow As A Means Of Enhanced Species Separation: A Three Dimensional Time-Accurate Cfd Analysis, Jennifer Crain Jan 2006

Oscillatory Flow As A Means Of Enhanced Species Separation: A Three Dimensional Time-Accurate Cfd Analysis, Jennifer Crain

Electronic Theses and Dissertations

A fluid that contains species in the presence of a concentration gradient generates unusual phenomena when it is forced into pulsatile motion. For example, each species in the fluid has an enhanced mass transport due to pure molecular diffusion. This enhancement takes place even if there is no net total flow over a cycle of the pulsatile motion. When more than one species in dilute amounts is present in an otherwise pure fluid, called a carrier, each species is transported at a different rate thereby causing a partial separation of the species. This idea traces back to hyperventilation studies done …

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Utilizing A Real Life Data Warehouse To Develop Freeway Travel Time Eliability Stochastic Models, Emam Emam Jan 2006

Utilizing A Real Life Data Warehouse To Develop Freeway Travel Time Eliability Stochastic Models, Emam Emam

Electronic Theses and Dissertations

During the 20th century, transportation programs were focused on the development of the basic infrastructure for the transportation networks. In the 21st century, the focus has shifted to management and operations of these networks. Transportation network reliability measure plays an important role in judging the performance of the transportation system and in evaluating the impact of new Intelligent Transportation Systems (ITS) deployment. The measurement of transportation network travel time reliability is imperative for providing travelers with accurate route guidance information. It can be applied to generate the shortest path (or alternative paths) connecting the origins and destinations especially under conditions …

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Coordination, Matchmaking, And Resource Allocation For Large-Scale Distributed Systems, Xin Bai Jan 2006

Coordination, Matchmaking, And Resource Allocation For Large-Scale Distributed Systems, Xin Bai

Electronic Theses and Dissertations

In this research, statistical models of airport delay and single flight arrival delay were developed. The models use the Airline On-Time Performance Data from the Federal Aviation Administration (FAA) and the Surface Airways Weather Data from the National Climatic Data Center (NCDC). Multivariate regression, ANOVA, neural networks and logistic regression were used to detect the pattern of airport delay, aircraft arrival delay and schedule performance. These models are then integrated in the form of a system for aircraft delay analysis and airport delay assessment. The assessment of an airport¡¯s schedule performance is discussed. The results of the research show that …

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Characterization Of Microstructural And Chemical Features In Cu-In-Ga-Se-S-Based Thin-Film Solar Cells, Ankush Halbe Jan 2006

Characterization Of Microstructural And Chemical Features In Cu-In-Ga-Se-S-Based Thin-Film Solar Cells, Ankush Halbe

Electronic Theses and Dissertations

Thin-film solar cells are potentially low-cost devices to convert sunlight into electricity. Improvements in the conversion efficiencies of these cells reduce material utilization cost and make it commercially viable. Solar cells from the Thin-Film Physics Group, ETH Zurich, Switzerland and the Florida Solar Energy Center (FSEC), UCF were characterized for defects and other microstructural features within the thin-film structure and at the interfaces using transmission electron microscopy (TEM). The present thesis aims to provide a feedback to these groups on their deposition processes to understand the correlations between processing, resulting microstructures, and the conversion efficiencies of these devices. Also, an …

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Hydrologic Mass Balance Of Pervious Concrete Pavement With Sandy Soils, Thomas Kunzen Jan 2006

Hydrologic Mass Balance Of Pervious Concrete Pavement With Sandy Soils, Thomas Kunzen

Electronic Theses and Dissertations

Use of pervious concrete pavement as a method of stormwater management has shown great promise in previous studies. Reduction in runoff, water quality improvements, and long-term economic benefits are but a few of its many advantages. Regulatory agencies such as the St. Johns River Water Management District require further research into the performance of pervious concrete pavement before granting credits for its use as a best management practice in controlling stormwater. As a part of a larger series of studies by UCF's Stormwater Management Academy, this thesis studies the hydrologic mass balance of pervious concrete pavement in sandy soil common …

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Substituting Live Training With Virtual Training By Means Of A Commercial Off The Shelf, First Person Shooter Computer Game And The Effect On Performance, George Kneuper Ii Jan 2006

Substituting Live Training With Virtual Training By Means Of A Commercial Off The Shelf, First Person Shooter Computer Game And The Effect On Performance, George Kneuper Ii

Electronic Theses and Dissertations

This research measures the change in Army ROTC cadets' tactical performance when up to 75% of their tactical live training is replaced with training done on a computer. An ROTC instructor from any of the 270 programs across the nation can take this research and implement a training plan utilizing a relatively cheap off the shelf computer game and save their program: cadet and cadre time, training dollars, and transportation/equipment/training area resources, while seeing no degradation in their cadets' performance. Little research has been done on the effect of replacing live simulation with virtual simulation. With this in mind, six …

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Multiple View Geometry For Video Analysis And Post-Production, Xiaochun Cao Jan 2006

Multiple View Geometry For Video Analysis And Post-Production, Xiaochun Cao

Electronic Theses and Dissertations

Multiple view geometry is the foundation of an important class of computer vision techniques for simultaneous recovery of camera motion and scene structure from a set of images. There are numerous important applications in this area. Examples include video post-production, scene reconstruction, registration, surveillance, tracking, and segmentation. In video post-production, which is the topic being addressed in this dissertation, computer analysis of the motion of the camera can replace the currently used manual methods for correctly aligning an artificially inserted object in a scene. However, existing single view methods typically require multiple vanishing points, and therefore would fail when only …

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Collaboration Enforcement In Mobile Ad Hoc Networks, Ning Jiang Jan 2006

Collaboration Enforcement In Mobile Ad Hoc Networks, Ning Jiang

Electronic Theses and Dissertations

Mobile Ad hoc NETworks (MANETs) have attracted great research interest in recent years. Among many issues, lack of motivation for participating nodes to collaborate forms a major obstacle to the adoption of MANETs. Many contemporary collaboration enforcement techniques employ reputation mechanisms for nodes to avoid and penalize malicious participants. Reputation information is propagated among participants and updated based on complicated trust relationships to thwart false accusation of benign nodes. The aforementioned strategy suffers from low scalability and is likely to be exploited by adversaries. To address these problems, we first propose a finite state model. With this technique, no reputation …

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The Effects Of Ph On Enhanced Biological Phosphorus Removal (Ebpr) With Propionic Acid As The Dominant Volatile Fatty Acid (Vfa), Seyed Malekjahani Jan 2006

The Effects Of Ph On Enhanced Biological Phosphorus Removal (Ebpr) With Propionic Acid As The Dominant Volatile Fatty Acid (Vfa), Seyed Malekjahani

Electronic Theses and Dissertations

pH control is a tool to improve some aspects of Enhanced Biological Phosphorus Removal (EBPR) process. Filipe et al (2001a, 2001b, and 2001c) found strong evidence that the stability of EBPR systems can be improved by increasing the pH of the anaerobic zone, thereby creating conditions where phosphorus-accumulating organisms (PAOs) are able to take up acetate faster than glycogen-accumulating organisms (GAOs). They explained this observation by comparing the growth rate of phosphorus-accumulating organisms (PAOs) and glycogen-accumulating organisms (GAOs) and found that pH has little effect on PAOs growth rate but adversely affects GAOs growth rate when it increases (at pH …

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System Identification And Fault Detection Of Complex Systems, Dapeng Luo Jan 2006

System Identification And Fault Detection Of Complex Systems, Dapeng Luo

Electronic Theses and Dissertations

The proposed research is devoted to devising system identification and fault detection approaches and algorithms for a system characterized by nonlinear dynamics. Mathematical models of dynamical systems and fault models are built based on observed data from systems. In particular, we will focus on statistical subspace instrumental variable methods which allow the consideration of an appealing mathematical model in many control applications consisting of a nonlinear feedback system with nonlinearities at both inputs and outputs. Different solutions within the proposed framework are presented to solve the system identification and fault detection problems. Specifically, Augmented Subspace Instrumental Variable Identification (ASIVID) approaches …

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Modeling The Influences Of Personality Preferences On The Selection Of Instructional Strategies Inintelligent Tutoring Systems, Robert Sottilare Jan 2006

Modeling The Influences Of Personality Preferences On The Selection Of Instructional Strategies Inintelligent Tutoring Systems, Robert Sottilare

Electronic Theses and Dissertations

This thesis hypothesizes that a method for selecting instructional strategies (specifically media) based in part on a relationship between learning style preference and personality preference provides more relevant and understandable feedback to students and thereby higher learning effectiveness. This research investigates whether personality preferences are valid predictors of learning style preferences. Since learning style preferences are a key consideration in instructional strategies and instructional strategies are a key consideration in learning effectiveness, this thesis contributes to a greater understanding of the relationship between personality preferences and effective learning in intelligent tutoring systems (ITS). This research attempts to contribute to the …

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The Effectiveness Of Data Codes And Hardware Selection To Mitigate Scintillation Effects On Free Space Optical Data Transmission, Keith Stein Jan 2006

The Effectiveness Of Data Codes And Hardware Selection To Mitigate Scintillation Effects On Free Space Optical Data Transmission, Keith Stein

Electronic Theses and Dissertations

The design of an optical communication link must plan for the random effects of atmospheric turbulence. This study analyses data from an experiment which transmitted from a laser located 8 meters above ground over a 13 Km range to coherent detection devices approximately 162 meters above ground. The effects of a fading and surging beam wave were considered in regards to code techniques for error correction, amplitude modulation and hardware architecture schemes. This study simulated the use of arrays and large apertures for the receiving devices, and compared the resultant scintillation index with the theoretical calculations.

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Text-Image Restoration And Text Alignment For Multi-Engine Optical Character Recognition Systems, Nikolai Kozlovski Jan 2006

Text-Image Restoration And Text Alignment For Multi-Engine Optical Character Recognition Systems, Nikolai Kozlovski

Electronic Theses and Dissertations

Previous research showed that combining three different optical character recognition (OCR) engines (ExperVision® OCR, Scansoft OCR, and Abbyy® OCR) results using voting algorithms will get higher accuracy rate than each of the engines individually. While a voting algorithm has been realized, several aspects to automate and improve the accuracy rate needed further research. This thesis will focus on morphological image preprocessing and morphological text restoration that goes to OCR engines. This method is similar to the one used in restoration partial finger prints. Series of morphological dilating and eroding filters of various mask shapes and sizes were applied to text …

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Heuristic Prioritization Of Emergency Evacuation Staging To Reduce Clearance Time, Steven Mitchell Jan 2006

Heuristic Prioritization Of Emergency Evacuation Staging To Reduce Clearance Time, Steven Mitchell

Electronic Theses and Dissertations

A region's evacuation strategy encompasses a variety of areas and needs. Primary among these is the minimization of total evacuation time, represented in models as the clearance time estimate (CTE). A generic testbed simulation network model was developed. An input/output (I/O) analysis was performed to establish a theoretical baseline CTE. Results were compared with simulations; analysis showed that the I/O method underestimated simulated CTE as a function of network size, with a correction factor range of 1.09 to 1.19. A regression model was developed for the generic network. Predictors were total trips, and network size defined as a function of …

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Design And Characterization Of Noveldevices For New Generation Of Electrostaticdischarge (Esd) Protection Structures, Javier Salcedo Jan 2006

Design And Characterization Of Noveldevices For New Generation Of Electrostaticdischarge (Esd) Protection Structures, Javier Salcedo

Electronic Theses and Dissertations

The technology evolution and complexity of new circuit applications involve emerging reliability problems and even more sensitivity of integrated circuits (ICs) to electrostatic discharge (ESD)-induced damage. Regardless of the aggressive evolution in downscaling and subsequent improvement in applications' performance, ICs still should comply with minimum standards of ESD robustness in order to be commercially viable. Although the topic of ESD has received attention industry-wide, the design of robust protection structures and circuits remains challenging because ESD failure mechanisms continue to become more acute and design windows less flexible. The sensitivity of smaller devices, along with a limited understanding of the …

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An Ocean Surface Wind Vector Model Function For A Spaceborne Microwave Radiometer And Its Application, Seubson Soisuvarn Jan 2006

An Ocean Surface Wind Vector Model Function For A Spaceborne Microwave Radiometer And Its Application, Seubson Soisuvarn

Electronic Theses and Dissertations

Ocean surface wind vectors over the ocean present vital information for scientists and forecasters in their attempt to understand the Earth's global weather and climate. As the demand for global wind velocity information has increased, the number of satellite missions that carry wind-measuring sensors has also increased; however, there are still not sufficient numbers of instruments in orbit today to fulfill the need for operational meteorological and scientific wind vector data. Over the last three decades operational measurements of global ocean wind speeds have been obtained from passive microwave radiometers. Also, vector ocean surface wind data were primarily obtained from …

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Safety Analyses At Signalized Intersections Considering Spatial, Temporal And Site Correlation, Xuesong Wang Jan 2006

Safety Analyses At Signalized Intersections Considering Spatial, Temporal And Site Correlation, Xuesong Wang

Electronic Theses and Dissertations

Statistics show that signalized intersections are among the most dangerous locations of a roadway network. Different approaches including crash frequency and severity models have been used to establish the relationship between crash occurrence and intersection characteristics. In order to model crash occurrence at signalized intersections more efficiently and eventually to better identify the significant factors contributing to crashes, this dissertation investigated the temporal, spatial, and site correlations for total, rear-end, right-angle and left-turn crashes. Using the basic regression model for correlated crash data leads to invalid statistical inference, due to incorrect test statistics and standard errors based on the misspecified …

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Study Of Nanoscale Cmos Device And Circuit Reliability, Chuanzhao Yu Jan 2006

Study Of Nanoscale Cmos Device And Circuit Reliability, Chuanzhao Yu

Electronic Theses and Dissertations

The development of semiconductor technology has led to the significant scaling of the transistor dimensions -The transistor gate length drops down to tens of nanometers and the gate oxide thickness to 1 nm. In the future several years, the deep submicron devices will dominate the semiconductor industry for the high transistor density and the corresponding performance enhancement. For these devices, the reliability issues are the first concern for the commercialization. The major reliability issues caused by voltage and/or temperature stress are gate oxide breakdown (BD), hot carrier effects (HCs), and negative bias temperature instability (NBTI). They become even more important …

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Development Of A Simplified Finite Element Approach For Frp Bridge Decks., Jignesh Vyas Jan 2006

Development Of A Simplified Finite Element Approach For Frp Bridge Decks., Jignesh Vyas

Electronic Theses and Dissertations

Moveable bridges in Florida typically use open steel grid decks due to the weight limitations. However, these decks present rideability, environmental, and maintenance problems, for they are typically less skid resistant than a solid riding surface, create loud noises, and allow debris to fall through the grids. Replacing open steel grid decks that are commonly used in moveable bridges with a low-profile FRP deck can improve rider safety and reduce maintenance costs, while satisfying the strict weight requirement for such bridges. The performance of the new deck system, which includes fatigue and failure tests were performed on full-size panels in …

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An Assessment Of Alignment Between Project Complexity And Project Management Style, Alper Camci Jan 2006

An Assessment Of Alignment Between Project Complexity And Project Management Style, Alper Camci

Electronic Theses and Dissertations

The main drivers for this research are the complexities associated with the project management and an organization's project management style in dealing with these complexities. This research aims to demonstrate that alignment between project complexity and project management style increases project performance and decreases project issues, and also, with increased project issues, project performance deteriorates. In order to test these claims, this research developed measures for assessing project complexity, project management styles and project issues by employing a survey of project management professionals. The measure for project complexity is based on a taxonomy with four categories: organizational complexity, product complexity, …

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Debris Characterization And Mitigation Of Droplet Laser Plasma Sources For Euv Lithography, Kazutoshi Takenoshita Jan 2006

Debris Characterization And Mitigation Of Droplet Laser Plasma Sources For Euv Lithography, Kazutoshi Takenoshita

Electronic Theses and Dissertations

Extreme ultraviolet lithography (EUVL) is a next generation lithographic techniques under development for fabricating semiconductor devices with feature sizes smaller than 32 nm. The optics to be used in the EUVL steppers is reflective optics with multilayer mirror coatings on each surface. The wavelength of choice is 13.5 nm determined by the optimum reflectivity of the mirror coatings. The light source required for this wavelength is derived from a hot-dense plasma produced by either a gas discharge or a laser. This study concentrate only on the laser produced plasma source because of its advantages of scalability to higher repetition rates. …

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Using Augmented Reality For Studying Left Turn Maneuver At Un-Signalized Intersection And Horizontal Visibility Blockage, Ghada Moussa Jan 2006

Using Augmented Reality For Studying Left Turn Maneuver At Un-Signalized Intersection And Horizontal Visibility Blockage, Ghada Moussa

Electronic Theses and Dissertations

Augmented reality "AR" is a promising paradigm that can provide users with real-time, high-quality visualization of a wide variety of information. In AR, virtual objects are added to the real-world view in a real time. Using the AR technology can offer a very realistic environment for driving enhancement as well as driving performance testing under different scenarios. This can be achieved by adding virtual objects (people, vehicles, hazards, and other objects) to the normal view while driving in a safe controlled environment. In this dissertation, the feasibility of adapting the AR technology into traffic engineering was investigated. Two AR systems; …

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Ten Step Manufacturing Problem Solvingprocess, Afsoun Panahi Jan 2006

Ten Step Manufacturing Problem Solvingprocess, Afsoun Panahi

Electronic Theses and Dissertations

The ten step problem solving is created to capture and resolve all issues that arise with designing, developing, manufacturing and delivering a new vehicle produce. These steps will provide a common process, which effectively defines and resolves concerns and prevents their recurrence. Step 1: Prepare for the process Step 2: Establish Team Step 3: Describe the Problem Step 4: Develop short term containment action Step 5: Define and verify root cause and escape point Step 6: Choose and verify permanent corrective actions Step 7: Implement and validate permanent corrective actions Step 8: Prevent recurrence Step 9: Recognize team and individual …

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Intrusion Detection In Wireless Sensor Networks, Hong Nhung Nguyen Jan 2006

Intrusion Detection In Wireless Sensor Networks, Hong Nhung Nguyen

Electronic Theses and Dissertations

There are several applications that use sensor motes and researchers continue to explore additional applications. For this particular application of detecting the movement of humans through the sensor field, a set of Berkley mica2 motes on TinyOS operating system is used. Different sensors such as pressure, light, and so on can be used to identify the presence of an intruder in the field. In our case, the light sensor is chosen for the detection. When an intruder crosses the monitored environment, the system detects the changes of the light values, and any significant change meaning that a change greater than …

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Improving Routing Efficiency, Fairness, Differentiated Servises And Throughput In Optical Networks, Bin Zhou Jan 2006

Improving Routing Efficiency, Fairness, Differentiated Servises And Throughput In Optical Networks, Bin Zhou

Electronic Theses and Dissertations

Wavelength division multiplexed (WDM) optical networks are rapidly becoming the technology of choice in next-generation Internet architectures. This dissertation addresses the important issues of improving four aspects of optical networks, namely, routing efficiency, fairness, differentiated quality of service (QoS) and throughput. A new approach for implementing efficient routing and wavelength assignment in WDM networks is proposed and evaluated. In this approach, the state of a multiple-fiber link is represented by a compact bitmap computed as the logical union of the bitmaps of the free wavelengths in the fibers of this link. A modified Dijkstra's shortest path algorithm and a wavelength …

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Ultrawideband Indoor Location And Tracking System, Qing Chen Jan 2006

Ultrawideband Indoor Location And Tracking System, Qing Chen

Electronic Theses and Dissertations

The objective of this thesis is to demonstrate an indoor intruder location and tracking system with UltraWideBand (UWB) technology and use data compression and Constant False Alarm Rate (CFAR) techniques to improve the performance of the location system. Reliable and accurate indoor positioning requires a local replacement for GPS systems since satellite signals are not available indoors. UWB systems are particularly suitable for indoor location systems due their inherent capabilities such as low-power, multi-path rejection, and wide bandwidth. In our application, we are using UWB radios as a radar system for tracking targets in indoor locations. We also use Discrete …

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Modeling, Simulation, And Visualization Of 3d Lung Dynamics, Anand Santhanam Jan 2006

Modeling, Simulation, And Visualization Of 3d Lung Dynamics, Anand Santhanam

Electronic Theses and Dissertations

Medical simulation has facilitated the understanding of complex biological phenomenon through its inherent explanatory power. It is a critical component for planning clinical interventions and analyzing its effect on a human subject. The success of medical simulation is evidenced by the fact that over one third of all medical schools in the United States augment their teaching curricula using patient simulators. Medical simulators present combat medics and emergency providers with video-based descriptions of patient symptoms along with step-by-step instructions on clinical procedures that alleviate the patient's condition. Recent advances in clinical imaging technology have led to an effective medical visualization …

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Optimizing The Global Performance Of Build-To-Order Supply Chains, Tarek Shaalan Jan 2006

Optimizing The Global Performance Of Build-To-Order Supply Chains, Tarek Shaalan

Electronic Theses and Dissertations

Build-to-order supply chains (BOSCs) have recently received increasing attention due to the shifting focus of manufacturing companies from mass production to mass customization. This shift has generated a growing need for efficient methods to design BOSCs. This research proposes an approach for BOSC design that simultaneously considers multiple performance measures at three stages of a BOSC – Tier I suppliers, the focal manufacturing company and Tier I customers (product delivery couriers). We present a heuristic solution approach that constructs the best BOSC configuration through the selection of suppliers, manufacturing resources at the focal company and delivery couriers. The resulting configuration …

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Simulation And Continuance Of Operation For The Use Of Transit (Lynx) To Be Used In Emergency Evacuation Incidents, Noor Elmitiny Jan 2006

Simulation And Continuance Of Operation For The Use Of Transit (Lynx) To Be Used In Emergency Evacuation Incidents, Noor Elmitiny

Electronic Theses and Dissertations

The evacuation planning has become an important issue addressed by many research studies and publications aiming to improve the security of the daily life for our public inside the United States of America. The main objective of this research was to address the growing need for evacuation planning using traffic simulation. With increased interests and awareness in emergency evacuation and first responder access to emergencies in public locations (airports, transit stations, ports or stadiums), the traffic simulation can be helpful in orchestrating the traffic flow during emergencies. Related to this issue, Federal Transit Administration has issued a large number of …

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