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Articles 121 - 150 of 164

Full-Text Articles in Operations Research, Systems Engineering and Industrial Engineering

An Investigation Of Metaheuristics Using Path- Relinking On The Quadratic Assignment Problem, Thashika Rupasinghe Dec 2010

An Investigation Of Metaheuristics Using Path- Relinking On The Quadratic Assignment Problem, Thashika Rupasinghe

All Dissertations

The Quadratic Assignment Problem (QAP) is a widely researched, yet complex, combinatorial optimization problem that is applicable in modeling many real-world problems. Specifically, many optimization problems are formulated as QAPs. To resolve QAPs, the recent trends have been to use metaheuristics rather than exact or heuristic methods, and many researchers have found that the use of hybrid metaheuristics is actually more effective. A newly proposed hybrid metaheuristic is path relinking (PR), which is used to generate solutions by combining two or more reference solutions. In this dissertation, we investigated these diversification and intensification mechanisms using QAP. To satisfy the extensive …

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Comprehensive Thermal Modeling Of Power Split Hybrid Power-Train And Electronics, Abdel Mayyas Dec 2010

Comprehensive Thermal Modeling Of Power Split Hybrid Power-Train And Electronics, Abdel Mayyas

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Hybrid electric vehicle (HEV) uses both internal combustion engine (ICE) with an electric system. The combination of the electric power train with the ICE is intended to achieve both better fuel economies than the conventional vehicles and better performance. Several types of HEV exist with different layouts. Recent HEVs' make use of regenerative braking, which converts the vehicles' kinetic energy into electric energy instead of wasting it as heat as conventional brakes do. A hybrid-electric is more fuel efficient than ICE and has less environmental impact.
The new HEV with its new Key Characteristics and Configurations (i.e. Mechanical complexity, Multiple …

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Order Picking And Storage Using Stackable Pallets In A Warehouse, Ahmed Hassan Aly Dec 2010

Order Picking And Storage Using Stackable Pallets In A Warehouse, Ahmed Hassan Aly

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Quarter Billion dollars could be saved annually by double stacking pallets. A forklift storing 100 double stacked pallets saves 2.5 working hours versus single pallets. More than one billion pallets and cases handled between Wal-Mart distribution centers according to BEA White Paper (2006) [1], assume only 500 million were stackable pallets. This translates to 12.5 million working hours. If a forklift driver earns $20 per hour, then $250 million can be saved.
Moreover, handling double stacked pallets takes up to 46 % of total time to pick and store. This is a significant element that was ignored in literature. All …

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Modeling Microbial And Nutrient Dynamics In Zero-Discharge Aquaculture Systems, Kendall Kirk Dec 2010

Modeling Microbial And Nutrient Dynamics In Zero-Discharge Aquaculture Systems, Kendall Kirk

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A finite element, finite difference model was developed to predict nutrient and microbial dynamics in recirculating aquaculture systems. Total ammonia nitrogen, nitrite, nitrate, chemical oxygen demand, and dissolved oxygen concentrations are predicted in addition to growth and decay of algae, Nitrosomonas, Nitrobacter, denitrifying heterotrophs, and aerobic heterotrophs. Inputs to the model include temperature, photosynthetically available radiation, feed application rate, pH, aeration/mixing energy, water exchange configuration, water exchange rate, tilapia biomass, and dissolved oxygen concentration. Up to 10 exchanged units may be included, user-definable as continuous stirred tank reactors or sequencing batch reactors. Demonstration of the model's utility was demonstrated through …

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Assortment Planning For Multiple Quality Levels Using Locational Choice, Mark Mcelreath Dec 2010

Assortment Planning For Multiple Quality Levels Using Locational Choice, Mark Mcelreath

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Assortment planning is the process in which a retailer selects a product line to offer to customers and is a key determinant of a retailer's profit. We consider the assortment planning problem using a locational choice model for customer product selection and allow for both horizontal and vertical product differentiation. When the distribution of customer preference is unimodal, the optimal solutions for this problem are unknown. We propose two solution philosophies for generating product assortments. First, we introduce a metaheuristic representation for the problem and test the performance of three metaheuristic techniques. We suggest that a tabu search or genetic …

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Sensor Based Nitrogen Management For Cotton Production In Coastal Plain Soils, Wesley Porter Aug 2010

Sensor Based Nitrogen Management For Cotton Production In Coastal Plain Soils, Wesley Porter

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The main objective of this four year study was to develop, refine, and employ sensor-based algorithims to determine the mid season nitrogen requirements for production of irrigated and dryland cotton (Gossypium hirsutum L.) in Coastal Plains soils. The secondary objective of the project was to develop and test equipment for variable rate application of nitrogen to commerical cotton fields utilizing the developed algorithim. Two different production fields at Clemson's Edisto Research and Education Center near Blackville, SC were used. One field, equiped with an overhead irrigation system, was used during the 2007 and 2010 production seasons to develop the algorithm …

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Remote Usability Testing - A New Approach Facilitated By Virtual Worlds, Kapil Chalil Madathil Aug 2010

Remote Usability Testing - A New Approach Facilitated By Virtual Worlds, Kapil Chalil Madathil

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Synchronous remote usability testing, involves a facilitator conducting a usability test in real time, interacting with a participant who is remote. This study proposes a new methodology for conducting these studies using a three-dimensional virtual world, Wonderland, and compares it with two other commonly used synchronous usability test methods: the traditional lab approach and WebEx, a web-based conferencing and screen sharing approach.
The study involved 48 participants in total, 36 test subjects and 12 test facilitators. These 36 were equally divided among the three environments with the 12 test facilitators being paired with one participant in each of the environments. …

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Estimation And Control Of Robotic Radiation-Based Processes, Fan Zeng Aug 2010

Estimation And Control Of Robotic Radiation-Based Processes, Fan Zeng

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This dissertation presents a closed-loop control and state estimation framework for a class of distributed-parameter processes employing a moving radiant actuator. These radiation-based processes have the potential to significantly reduce the energy consumption and environmental impact of traditional industrial processes. Successful implementation of these approaches in large-scale applications requires precise control systems. This dissertation provides a comprehensive framework for: 1) integration of trajectory generation and feedback control, 2) online distributed state and parameter estimation, and 3) optimal coordination of multiple manipulated variables, so as to achieve elaborate control of these radiation-based processes for improved process quality and energy efficiency.
The …

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Simulation And Mathematical Modeling To Support Community-Wide Evacuation Decisions For Multiple Population Groups, Jun Duanmu Aug 2010

Simulation And Mathematical Modeling To Support Community-Wide Evacuation Decisions For Multiple Population Groups, Jun Duanmu

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Evacuating a large population from an at-risk area has been the subject of extensive research over the past few decades. In order to measure trip completion and total evacuation times accurately, most researchers have implemented some combination of simulation and optimization methods to provide vehicular flow and congestion data. While the general at-risk population comprises the majority of travelers on the road network, there are often specific groups to consider when assessing the ability to evacuate an entire population. In particular, healthcare facilities (e.g., hospitals) may require evacuation, and the trip times may become an important health issue for patients …

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Principal Component Analysis Based Image Fusion Routine With Application To Stamping Split Detection, Yi Zhou Aug 2010

Principal Component Analysis Based Image Fusion Routine With Application To Stamping Split Detection, Yi Zhou

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This dissertation presents a novel thermal and visible image fusion system with application in online automotive stamping split detection. The thermal vision system scans temperature maps of high reflective steel panels to locate abnormal temperature readings indicative of high local wrinkling pressure that causes metal splitting. The visible vision system offsets the blurring effect of thermal vision system caused by heat diffusion across the surface through conduction and heat losses to the surroundings through convection. The fusion of thermal and visible images combines two separate physical channels and provides more informative result image than the original ones.
Principal Component Analysis …

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Prioritizing Patients For Emergency Evacuation From A Healthcare Facility, Ashley Childers Aug 2010

Prioritizing Patients For Emergency Evacuation From A Healthcare Facility, Ashley Childers

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The success of a healthcare facility evacuation depends on communication and decision-making at all levels of the organization, from the coordinators at incident command to the clinical staff who actually carry out the evacuation. One key decision is the order in which each patient is chosen for evacuation. While the typical planning assumption is that all patients are to be evacuated, there may not always be adequate time or resources available to move all patients. In these cases, prioritizing or ordering patients for evacuation becomes an extremely difficult decision to make. These decisions should be based on the current state …

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'Transfer Effect Study Of A Virtual Borescope In Training Aircraft Maintenance Technicians', Melissa Dorlette Paul May 2010

'Transfer Effect Study Of A Virtual Borescope In Training Aircraft Maintenance Technicians', Melissa Dorlette Paul

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The Federal Aviation Administration (FAA) has acknowledged training as an important tactic to improve the trustworthiness of inspection. This study was conducted to test the transfer of the skills learned with a simulator into the real world. For this purpose, data from seventeen students in the AMT program of Greenville Technical College was analyzed. Objective data was taken to assess the group's performance on the simulator after each session of training. The comparison between two groups was made using objective data, collected while the subjects went through a test on a real engine and using the real borescope, and subjective …

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Maximizing Throughput Using Dynamic Resource Allocation And Discrete Event Simulation, Gregory Gunn May 2010

Maximizing Throughput Using Dynamic Resource Allocation And Discrete Event Simulation, Gregory Gunn

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This research studies a serial two stage production system with two flexible servers which can be dynamically assigned to either station. This is modeled using discrete event simulation and more specifically the Arena software package by Rockwell. The goal is to determine dynamic allocation policies based upon the inventory level at each station to maximize the throughput of finished goods out of the system. This model adds to previous work by including actual switching time. The effect of the pre-emptive resume assumption is gauged, and the effectiveness of the OptQuest optimization package is also tested. Studies are conducted to determine …

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Effectiveness Of Team-Building And Teamwork In Real And Virtual Worlds, Rachana Ranade Dec 2009

Effectiveness Of Team-Building And Teamwork In Real And Virtual Worlds, Rachana Ranade

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Given the increasing importance of globalization and collaboration, this research investigates the possibility of performing team-building training for globally dispersed teams using the capabilities of the virtual world Second Life. Three meeting conditions, the 3D virtual world Second Life, a combination of face-to-face and Second Life and face-to-face were evaluated. Thirty randomly assigned 3 person teams performed an ice-breaker session and then a team-building activity in each meeting condition. Four dependent variables were measured: task completion time; quality of task performance; the subjective satisfaction with the process based on group cohesiveness, perception of the process and satisfaction with the outcome; …

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A Logistic Regression Model To Predict Incident Severity Using The Human Factors Analysis And Classification System, Hrishikesh Kavade Dec 2009

A Logistic Regression Model To Predict Incident Severity Using The Human Factors Analysis And Classification System, Hrishikesh Kavade

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The Human Factors Analysis and Classification System (HFACS) is used to help identify causal factors that lead to human error. The framework has been used in a variety of industries to identify leading contributing factors of unsafe events, such as accidents, incidents and near misses. While traditional application of the HFACS framework to safety outcomes has allowed evaluators to identify leading causal issues based on frequency, little has been done to gain a more comprehensive view of the system's total risk. This work utilizes the concept of event severity along with the HFACS framework to help better identify target areas …

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Thermoelastic Behavior Of A Small Bearing Cage, Eric Planting Dec 2009

Thermoelastic Behavior Of A Small Bearing Cage, Eric Planting

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The full field non contact measurement of objects undergoing testing is one of interest for manufacturers of parts which are graded on their longevity. Unfortunately, for homogenous small parts with irregular geometries, such as bearing cages, the solution for testing is typically to use only a FEA model and compliment the testing of the model with simply cyclically loading the sample until failure. To better understand the stresses and behavior of a small object Thermoelasticity can be employed in order to see in a full field technique what stress patterns exist and their correlation to a FEA model.
The FEA …

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Performance Of Storm Water Stage And Quality Measuring Instruemtnation Of A Small Watershed Using A Remote Monitoring Station, Rebecca Crane Dec 2009

Performance Of Storm Water Stage And Quality Measuring Instruemtnation Of A Small Watershed Using A Remote Monitoring Station, Rebecca Crane

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ABSTRACT


As economic development proceeds special care must be taken to preserve and sustain our water resources. Monitoring the storm water from a watershed during a rainfall event can help quantify any changes in water quantity and quality. An accurate means of measuring flow is necessary for all watershed monitoring projects. This study was conducted to analyze the performance of stage, turbidity, and temperature measuring devices in a laboratory setting as well as on Honeycutt Creek in Clemson, South Carolina.
The stage measuring devices under study include: a radar level sensor, ultrasonic transmitter, pressure transducer, and a bubbler module. A …

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A Particle Swarm Optimization Using Random Keys For Flexible Flow Shop Scheduling Problem With Sequence Dependent Setup Times, Vinodh Sankaran Dec 2009

A Particle Swarm Optimization Using Random Keys For Flexible Flow Shop Scheduling Problem With Sequence Dependent Setup Times, Vinodh Sankaran

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In this research, a particle swarm optimization algorithm (PSO) using random keys is developed to schedule flexible flow lines with sequence dependent setup times to minimize makespan. The flexible flow line scheduling problem is a branch of production scheduling and is found in industries such as printed circuit board and automobile manufacturing. It is well known that this problem is NP-hard. For this reason, we approach the problem by implementing a particle swarm optimization (PSO), a metaheuristic which is inspired by the motion of a flock of birds or a school of fish searching for food. The proposed PSO has …

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Sensor-Based Soil Water Monitoring To More Effectively Manage Agricultural Water Resources In Coastal Plain Soils, Christopher Bellamy Dec 2009

Sensor-Based Soil Water Monitoring To More Effectively Manage Agricultural Water Resources In Coastal Plain Soils, Christopher Bellamy

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Cotton (Gossypium hirsutum L.) is widely grown in the United States with 5.7 million ha grown nationally and 1.2 million ha grown in the humid southeastern states in 2005. From 1969 to 2003, agricultural irrigated farmland acreage and total water applied increased by over 40% and 11% respectively to include a total of 55.3 million acres in 2002. Combined with recent and more frequent drought periods and legal water conflicts between states, there has been an increased interest in more effective southeastern water management, thus making the need to develop improved irrigation scheduling methods and enhanced water use efficiency of …

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2-D And 3-D Assessment Of Cambered And Symmetric Airfoils: A Cfd Study, Tuncay Kamas Dec 2009

2-D And 3-D Assessment Of Cambered And Symmetric Airfoils: A Cfd Study, Tuncay Kamas

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A two dimensional and three dimensional computational study has been carried out respectively regarding aerodynamic forces affecting a symmetric airfoil, NACA0015 and a cambered airfoil, NACA2414. The negative lift (down force) and drag forces were predicted through the simulation of airflows over inverted rear-wings in different configurations namely; varying incidences i.e. angles of attack of the airfoils, two dimensional cross section of the inverted rear wings to be mounted on back of a car, and varying speeds of initial airflow.
The downforce increases as the angle of attack increases however, if an inverted rear wing is fixed on a car …

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An Investigation On The Use And Flexibility Of Genetic Algorithms For Logistic Regression, Sara Yoder Dec 2009

An Investigation On The Use And Flexibility Of Genetic Algorithms For Logistic Regression, Sara Yoder

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Social scientists and other users of large data sets often desire a model to predict the probability that some condition exists, such as the probability that a person has diabetes or that a credit card transaction will be fraudulent. In general, this can be done by data mining techniques, which allow multiple records of data composed of numerous independent variables and one dependent variable to be examined in a statistical fashion to make a predictive model. One particular technique used is logistic regression. Logistic regression forms a predictive model based on a set of independent variables by assigning coefficients to …

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Human Error In Mining: A Multivariable Analysis Of Mining Accidents/Incidents In Queensland, Australia And The United States Of America Using The Human Factors Analysis And Classification System Framework, Jessica Patterson Dec 2009

Human Error In Mining: A Multivariable Analysis Of Mining Accidents/Incidents In Queensland, Australia And The United States Of America Using The Human Factors Analysis And Classification System Framework, Jessica Patterson

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Historically, mining has been viewed as an inherently high-risk industry. Nevertheless, the introduction of new technology and a heightened concern for safety has yielded marked reductions in accident and injury rates over the last several decades. In an effort to further reduce these rates, the human factors associated with incidents/accidents need to be addressed. A modified version of the Human Factors Classification and Analysis System (HFCAS-MI) was used to analyze lost time accidents and high-potential incidents from across Queensland, Australia and fatal accidents from the United States of America (USA) to identify human factor trends and system deficiencies within mining. …

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A Scanpath Comparison Of The Salient Features Of Weather Among General Aviation Pilots Based On Training And Experience, Michael Sawyer Dec 2009

A Scanpath Comparison Of The Salient Features Of Weather Among General Aviation Pilots Based On Training And Experience, Michael Sawyer

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Over the last 20 years the number of annual accidents in general aviation has seen a steady decline. The annual number of fatal accidents, however, has remained relatively stable. Adverse weather is consistently cited as a leading cause of fatal accidents in general aviation; weather accidents have a fatality rate nearly four times that of other general aviation accidents. Reviews of accident data reveal that often these accidents occur when inexperienced pilots who are certified only for visual flight rules flight continue into adverse weather. The Situation Assessment Hypothesis suggests these accidents occur when pilots fail to accurately recognize weather …

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Real-Time Vehicle Parameter Estimation And Adaptive Stability Control, John Limroth Dec 2009

Real-Time Vehicle Parameter Estimation And Adaptive Stability Control, John Limroth

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This dissertation presents a novel Electronic Stability Control (ESC) strategy that is capable of adapting to changing vehicle mass, tire condition and road surface conditions. The benefits of ESC are well understood with regard to assisting drivers to maintain vehicle control during extreme handling maneuvers or when extreme road conditions such as ice are encountered. However state of the art ESC strategies rely on known and invariable vehicle parameters such as vehicle mass, yaw moment of inertia and tire cornering stiffness coefficients. Such vehicle parameters may change over time, especially in the case of heavy trucks which encounter widely varying …

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Effects Of Meeting Spaces On The Performance Of A Concept Selection Task By Engineering Design Teams, Necmettin Ozkan Aug 2009

Effects Of Meeting Spaces On The Performance Of A Concept Selection Task By Engineering Design Teams, Necmettin Ozkan

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Given the increasing importance of collaboration and the resulting use of virtual tools, this research investigates the performance of engineering design teams using a concept selection task in three meeting spaces, face-to-face, 2D online and 3D virtual. Cisco's WebEx and Sun Microsystems' Wonderland were used as the 2D online meeting space and the 3D virtual environment, respectively. Twenty-four two-person design teams were formed and randomly assigned to the meeting spaces. Eight teams performed a cell-phone concept selection task in each meeting space. Four dependent variables were measured: task completion time, team satisfaction, self-evaluated quality and expert-evaluated quality. Following data collection, …

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Biohydrogen Production From Cull Peach Medium By Hyperthermophilic Bacterium Thermotoga Neapolitana, Abhiney Jain Aug 2009

Biohydrogen Production From Cull Peach Medium By Hyperthermophilic Bacterium Thermotoga Neapolitana, Abhiney Jain

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ABSTRACT
Thermotoga neapolitana is a marine hyperthermophilic bacterium that ferments various sugars to hydrogen and acetate. In this study, cull peaches were used as carbon source in a defined medium for biohydrogen production and produced 18 % to 25% hydrogen in the headspace. The hydrogen production varied from 6.4-7.7 mmol H2/g peach (dry weight). The hydrogen concentration did not increase after 20 hours of incubation. The final pH decreased to 4.9 after 20 hours. Unautoclaved peach medium can be used for hydrogen production. The hydrogen production did not increase with the increase in peach concentration from 50 g/L to 100 …

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High-Rate Channel Catfish Fingerling Production In The Partitioned Aquaculture System, Tim Wells May 2009

High-Rate Channel Catfish Fingerling Production In The Partitioned Aquaculture System, Tim Wells

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The objective of this 4-year research project was to evaluate the performance of channel catfish (Ictalurus punctatus) fingerling production in the Partitioned Aquaculture System (PAS). The goal was to demonstrate production of 80-gram minimum sized fingerlings in a single growing season, allowing for 100% market-size fish production after one additional season in the grow-out PAS.
A series of 2-inch airlift pumps fed by a single 3-hp low-head blower was found to be capable of supplying sufficient water flow-rate (in 2005, 2006, and 2007) of gpm per container to 9 cohorts. A series of 0.75-hp axial flow pumps (in 2005, 2006, …

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Design Of A Multi-Echelon Global Supply Chain Network With Microsoftå¨ Excel Premium Solver Plataform, Wilder Ferreira May 2009

Design Of A Multi-Echelon Global Supply Chain Network With Microsoftå¨ Excel Premium Solver Plataform, Wilder Ferreira

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I designed a global supply chain distribution model of one single product, with the objective of minimizing the costs of transportation, handling materials, duties and tariffs, production, and fixed infrastructure. The distribution network has a combination of manufacturing facilities (fixed and to-be-determined), warehouses (to-be-determined), distribution centers (to-be-determined), and customer zones at fixed locations. This network design is similar to the mathematical mixed-integer linear model from Tsiakis, Shah and Pantelides (2001). This model has been implemented in Microsoft Excel, using the Standard Simplex method from Frontline, Inc. This model optimizes the number of facilities worldwide (multi-echelon) along with the flow of …

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Development Of The Integrated Censored Robust-Tolerance Engineering Design Systems Via Improved Response Surface Modeling, Abdul-Baasit Shaibu May 2009

Development Of The Integrated Censored Robust-Tolerance Engineering Design Systems Via Improved Response Surface Modeling, Abdul-Baasit Shaibu

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In this dissertation, we intend to integrate censoring into robust-tolerance engineering using improved dual response surface modeling. This is perhaps the first attempt in the quality control literature. In the literature, response surface models have largely been restricted to second order (or quadratic) models and robust-tolerance designs have been restricted to situations involving complete observations. We intend to show that higher order response surface models can be more powerful in terms of prediction ability, and are therefore more reliable than the preferred quadratic models in the general context of robust design. We will also consider formulating robust and tolerance designs …

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Optimal And Heuristic Resource Allocation Policies In Serial Production Systems, Ramesh Arumugam Dec 2008

Optimal And Heuristic Resource Allocation Policies In Serial Production Systems, Ramesh Arumugam

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We have studied the optimal server allocation policies for a tandem queueing system under different system settings. Motivated by an industry project, we have studied a two stage tandem queueing system with arrival to the system and having two flexible servers capable of working at either of the stations. In our research, we studied the system under two different circumstances: modeling the system to maximize throughput without cost considerations, modeling the system to include switching and holding costs along with revenue for finished goods. In the maximizing throughput scenario, we considered two different types of server allocations: collaborative and non-collaborative. …

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