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Assessment Of Simulated And Real-World Autonomy Performance With Small-Scale Unmanned Ground Vehicles, William Peyton Johnson
Assessment Of Simulated And Real-World Autonomy Performance With Small-Scale Unmanned Ground Vehicles, William Peyton Johnson
Theses and Dissertations
Off-road autonomy is a challenging topic that requires robust systems to both understand and navigate complex environments. While on-road autonomy has seen a major expansion in recent years in the consumer space, off-road systems are mostly relegated to niche applications. However, these applications can provide safety and navigation to dangerous areas that are the most suited for autonomy tasks. Traversability analysis is at the core of many of the algorithms employed in these topics. In this thesis, a Clearpath Robotics Jackal vehicle is equipped with a 3D Ouster laser scanner to define and traverse off-road environments. The Mississippi State University …
Development Of A Three Degree-Of-Freedom Control Simulation For A Group 3 Large Unmanned Aircraft System, Majka Anna Wilczynski
Development Of A Three Degree-Of-Freedom Control Simulation For A Group 3 Large Unmanned Aircraft System, Majka Anna Wilczynski
Theses and Dissertations
Aircraft modeling and simulation has become increasingly important in the aviation world. Simulations allow for safer and more economical training prior to flight testing. In this project, a three degree-of-freedom control simulation coded in a MATLAB environment is used to assess and simulate the dynamic stability of group three unmanned aircraft system. By calculating, evaluating, and simulating the static and dynamic stability derivatives of the aircraft, this project will allow for the estimation of the handling qualities of an unmanned aircraft system. This can help mitigate risks that come along with altering the mass and aerodynamic properties of an aircraft, …
Self-Consistent Modeling Of Slip-Twin Interactions In Hcp Structures, Mukti Patel
Self-Consistent Modeling Of Slip-Twin Interactions In Hcp Structures, Mukti Patel
Theses and Dissertations
Parsing the effect of slip-twin interactions on the strain rate and thermal sensitivities of Magnesium (Mg) alloys has been a challenging endeavor for scientists preoccupied with the mechanical behavior of hexagonal close-packed alloys, especially those with great latent economic potential such as Mg. One of the main barriers is the travail entailed in fitting the various stress-strain behaviors at different temperatures, strain rates, loading directions applied to different starting textures. Taking on this task for two different Mg alloys presenting different textures and as such various levels of slip-twin interactions were modeled using VPSC code. A recently developed routine that …
Modeling Risk Analysis Of A Layered Commercial Solution For A Classified Program When A Patient Attacker Is Present, Marsella Farnam
Modeling Risk Analysis Of A Layered Commercial Solution For A Classified Program When A Patient Attacker Is Present, Marsella Farnam
Theses and Dissertations
Layered security systems pose significant challenges while attempting to monitor security related activities. The varying attributes embedded within each layer as well as the attribute interdependencies within and across layers takes measurement complexity to an exponential state. The many interdependencies at play in an interconnected infrastructure further exacerbates the ability to measure overall security assurance. Then enters the patient attacker who infiltrates one layer of this security system and waits for the opportune time to infiltrate another layer. The ability to simulate and understand risk with respect to time in this dynamic environment is critical to the decision maker who …
A Strategy To Reduce Total Cost Of Ownership Of The U.S. Air Force’S Airfield Pavements, Thomas Synovec
A Strategy To Reduce Total Cost Of Ownership Of The U.S. Air Force’S Airfield Pavements, Thomas Synovec
Theses and Dissertations
The U.S. Air Force (USAF) estimates it has a $33 billion (about 10 percent is airfield pavements) deferred maintenance backlog within its $263 billion infrastructure portfolio. Given the scope of this backlog and the importance of airfields, the USAF has a vested interest in finding strategies to help reverse this growing trend. Without an increase in funding, divestiture of excess infrastructure, or change in strategy, this backlog is estimated to climb to over $50 billion by 2030. Reversing the growing infrastructure backlog trend requires new methods and strategies to rethink how the USAF invests in its infrastructure. As such, the …
Multistage 2-Dof Rocket Trajectory Simulation Program For Freshmen Level Engineering Students, Zachery Doucet
Multistage 2-Dof Rocket Trajectory Simulation Program For Freshmen Level Engineering Students, Zachery Doucet
Theses and Dissertations
With the growing interest in space exploration, the need for professionals to be prepared for the job is ever more present. This project aims to satisfy that goal by presenting a MATLAB program for use by freshmen level engineering students that provides results for rocket trajectories within acceptable margins of accuracy. The initial stages of development were shaped by the decision to keep the program accessible to someone within the target demographic. As a result, a three-degree of freedom system was chosen, with focus put on amateur rocketry including high power rockets. Various methods were used to provide outputs for …
Multi-Lidar Placement, Calibration, And Co-Registration For Off-Road Autonomous Vehicle Operation, William Meadows
Multi-Lidar Placement, Calibration, And Co-Registration For Off-Road Autonomous Vehicle Operation, William Meadows
Theses and Dissertations
For autonomous vehicles, 3D, rotating LiDAR sensors are critically important towards the vehicle's ability to sense its environment. Generally, these sensors scan their environment, using multiple laser beams to gather information about the range and the intensity of the reflection from an object. For multi--LiDAR systems, the placement of the sensors determines the density of the combined point cloud. I perform preliminary research on the optimal LiDAR placement strategy for an off--road, autonomous vehicle known as the Halo project. I use simulation to generate large amounts of labeled LiDAR data that can be used to train and evaluate a neural …
Process Improvement Of Door Manufacturing Through Time Study And Simulation Using Lean Concepts, Chen Chen
Process Improvement Of Door Manufacturing Through Time Study And Simulation Using Lean Concepts, Chen Chen
Theses and Dissertations
This project investigated the effects of process capability, line station operation efficiency, and line balance on the product throughput of a wooden door manufacturing process using time-and-motion study and simulation methods. The problem-solving approach DMAIC was used to identify root causes to the problems and implemented the process improvements for the production line efficiency and throughput based on lean manufacturing concepts. The investigation results indicated that the main operation of the wooden door manufacturing process was based on manual and semi-automatic operations. The process capability of whole operation before implementing process improvements was around 600 doors monthly. The coefficient of …
Evaluating The Validity Of Latency Effects In Robotics Simulation, Leif T. Jensen
Evaluating The Validity Of Latency Effects In Robotics Simulation, Leif T. Jensen
Theses and Dissertations
Latency is a common issue found in robotics teleoperation that is not currently addressed in simulation. This study examined the effects of latency on operator performance for a robot teleoperation navigation task. Operators used a Logitech gamepad controller to teleoperate a robot through both a simulated environment and real-world environment. Both environments had the same dimensions and provided a path with obstacles the participant had to navigate. Participants performed this navigation task under three latency conditions, zero, low and high. Completion time, number of collisions, NASA-TLX, System Usability Survey, and User Experience survey were collected and participant performance compared for …
Discrete Fourier Transform On Global Data Analysis, Wenshuang Wang
Discrete Fourier Transform On Global Data Analysis, Wenshuang Wang
Theses and Dissertations
In this dissertation, we utilize the discrete Fourier analysis on axially symmetric data generation and nonparametric estimation. We first represent the axially symmetric process as Fourier series on circles with the Fourier random coefficients expressed as circularlysymmetric complex random vectors. We develop an algorithm to generate the axially symmetric data that follow the given covariance function. Our simulation study demonstrates that our approach performs comparable with the classical approach using the given axially symmetric covariance function directly, while at the same time significantly reducing computational costs. For the second contribution of this dissertation, we apply the discrete Fourier transform to …
Simulation Of An Axion Search Experiment, Yipeng Jiang
Simulation Of An Axion Search Experiment, Yipeng Jiang
Theses and Dissertations
The resolution of the strong CP problem postulates a new dark matter candidate known as the axion. Axions can couple with photons in the presence of a strong magnetic field. Light shining through wall method (LSW) uses a lead wall inside a cavity with a strong magnetic field to coupled axions with photons then detect axions when the axions cross the lead wall and convert back to photons. The axion signal and thermal noise are simulated and by comparing the simulated signals after they have been rectified and integrated, the sensitivity of the planned experiment was determined.
Dynamic Vehicle Routing In Emergency Evacuation, Yi Wen
Dynamic Vehicle Routing In Emergency Evacuation, Yi Wen
Theses and Dissertations
Since Hurricane Katrina, extensive studies have been conducted aiming to optimize the transit vehicle routing in the event of an emergency evacuation. However, the vast majority of the studies focus on solving the deterministic vehicle routing problem that all the evacuation data are known in advance. These studies are generally not practical in dealing with real-world problems which involve considerable uncertainty in the evacuation data set. In this dissertation, a SmartEvac system is developed for dynamic vehicle routing optimization in emergency evacuation. The SmartEvac system is capable of processing dynamic evacuation data in real time, such as random pickup requests, …
Catalytic Conversion Of Model Biomass-Derived Syngas To Hydrocarbons Via Fischer-Tropsch Synthesis, Jin Hu
Catalytic Conversion Of Model Biomass-Derived Syngas To Hydrocarbons Via Fischer-Tropsch Synthesis, Jin Hu
Theses and Dissertations
Biomass to Liquids via Fischer-Tropsch synthesis (BTL-FT) is regarded as one of the most promising routes for providing alternative solution to growing demand for energy and environmental protection. In Chapter I, the development and key issues of BTL-FT process (especially Fischer-Tropsch synthesis) were reviewed and identified. In Chapter II, Mo/HZSM-5 catalyst was synthesized using Incipient Wetness Impregnation method and tested in nitrogen rich model bio-syngas. Different operation parameters (temperature, pressure, and GHSV) were tested to investigate their influence on the catalytic performance. Those parameters were found to affect the performance significantly. Liquid samples from conversion were mainly composed of C8 …
Minimization Of Noise And Vibration Related To Driveline Imbalance Using Robust Design Processes, Omar Al-Shubailat
Minimization Of Noise And Vibration Related To Driveline Imbalance Using Robust Design Processes, Omar Al-Shubailat
Theses and Dissertations
Variation in vehicle noise, vibration and harshness (NVH) response can be caused by variability in design (e.g. tolerance), material, manufacturing, or other sources of variation. Such variation in the vehicle response causes a higher percentage of produced vehicles to have higher levels (out of specifications) of NVH leading to higher number of warranty claims and loss of customer satisfaction, which are proven costly. Measures must be taken to ensure less warranty claims and higher levels of customer satisfactions. As a result, original equipment manufacturers (OEMs) have implemented design for variation in the design process to secure an acceptable (or within …
Human Fatigue In Prolonged Mentally Demanding Work-Tasks: An Observational Study In The Field, Shaheen Ahmed
Human Fatigue In Prolonged Mentally Demanding Work-Tasks: An Observational Study In The Field, Shaheen Ahmed
Theses and Dissertations
Worker fatigue has been the focus of research for many years. However, there is limited research available on the evaluation and measurement of fatigue for prolonged mentally demanding activities. The objectives of the study are (1 )to evaluate fatigue for prolonged, mentally demanding work-tasks by considering task-dependent, task-independent and personal factors, (2) to identify effective subjective and objective fatigue measures, (3) to establish a relationship between time and factors that affect fatigue (4) to develop models to predict fatigue. A total of 16 participants, eight participants with western cultural backgrounds and eight participants with eastern cultural backgrounds, currently employed in …
Proposed Farm Bill Impact On Optimal Hedge Ratios For Crops, Trang Thu Tran
Proposed Farm Bill Impact On Optimal Hedge Ratios For Crops, Trang Thu Tran
Theses and Dissertations
Revenue insurance with shallow loss protection for farmers has been introduced recently. A common attribute of most shallow loss proposals is that they would be arearevenue triggered. The impact on optimal hedge ratios of combining these shallow loss insurance proposals with deep loss farm-level insurance is examined. Since crop insurance, commodity programs and forward pricing are commonly used concurrently to manage crop revenue risk, the optimal combinations of these tools are explored. Numerical analysis in the presence of yield, basis and futures price variability is used to find the futures hedge ratio which maximizes the certainty equivalent of a risk …
Assessment Of The Lactation Index For Managing White-Tailed Deer Populations, Kamen Lee Campbell
Assessment Of The Lactation Index For Managing White-Tailed Deer Populations, Kamen Lee Campbell
Theses and Dissertations
I analyzed precision and accuracy of lactation data to reflect actual fawn recruitment for various levels of fecundity, neonatal mortality, harvest intensity, and hunter selectivity. I evaluated and developed a correction equation to adjust for harvest date effects on lactation detectability. I compared metrics of site-specific fawn recruitment (e.g., lactation rates, hunter observation fawn-to-doe ratios, and post-season fawn-to-doe ratios) among themselves, and to site-specific indices of carnivore abundance, for 18 properties across Mississippi and Alabama. Accuracy of lactation rates are compromised due to variation at minimal harvest intensity and insensitivity to change in fetal rate or neonatal mortality. Lactation data …
Understanding Managerial Decisions About Global Sourcing: Offshoring And Reshoring Of Production, Raymond George Purnell
Understanding Managerial Decisions About Global Sourcing: Offshoring And Reshoring Of Production, Raymond George Purnell
Theses and Dissertations
As international commerce continues to emerge due to telecommunication and transportation breakthroughs, the eagerness of companies to send particular business functions offshore increases. Offshoring is the removal of a company function (particularly, manufacturing) from a domestic location to a remote destination. Since many developing economies contain low labor wages, companies in the United States and Europe are able to leverage cost savings by paying low compensation to foreign production employees. The low cost concept, though, does not always offer significant financial reward. For companies with particular product types, business models, or limited experience, offshoring proves to be an expensive mistake …
A Phenomenological Investigation Of Ignition And Combustion In Alternative-Fueled Engines, Saroj Kumar Jha
A Phenomenological Investigation Of Ignition And Combustion In Alternative-Fueled Engines, Saroj Kumar Jha
Theses and Dissertations
Current diesel technologies involve a broad spectrum of combustion regimes. Previous diesel combustion models either lack the universality across various combustion regimes or suffer computational cost. This dissertation discusses the development of a phenomenological framework to identify and understand key in-cylinder processes that influence the overall performance of a compression ignition engine. The first part of this research is focused on understanding the ignition delay (ID) of diesel fuel in a pilot-ignited partially premixed, low temperature natural gas (NG) combustion engine. Lean premixed low temperature NG combustion is achieved by using small pilot diesel sprays (2-3% of total fuel energy) …
A Simulation Environment For A Personal Portable Power System, Shane Leland Morrison
A Simulation Environment For A Personal Portable Power System, Shane Leland Morrison
Theses and Dissertations
With the increased requirements for personal portable power systems to be more capable and better matched to the load and the mission, manufacturers have become interested in improved methods for predicting the performance of these systems. Personal portable power systems must meet challenging energy and portability requirements that require better predictive knowledge of these systems in integrated systems with realistic mission scenarios. This thesis presents the development of a modeling and simulation environment to further expand and predict the needs and requirements of personal portable power systems. The proposed personal portable power system is a diverse system consisting of energy …
The Economic Feasibility Of Producing Sweet Sorghum As An Ethanol Feedstock In Mississippi, Joseph Andrew Linton
The Economic Feasibility Of Producing Sweet Sorghum As An Ethanol Feedstock In Mississippi, Joseph Andrew Linton
Theses and Dissertations
This study examines the feasibility of producing sweet sorghum as an ethanol feedstock in Mississippi. An enterprise budgeting system is used along with estimates of transportation costs to estimate farmers’ breakeven costs for producing and delivering sweet sorghum biomass. This breakeven cost for the farmer, along with breakeven costs for the producer based on wholesale ethanol price, production costs, and transportation and marketing costs for the refined ethanol, is used to estimate the amounts that farmers and ethanol producers would be willing to accept (WTA) and willing to pay (WTP), respectively, for sweet sorghum biomass. These WTA and WTP estimates …
Radio Frequency Evaluation Of Oriented Strand Board, Xiaojian Liu
Radio Frequency Evaluation Of Oriented Strand Board, Xiaojian Liu
Theses and Dissertations
Oriented strandboard (OSB) is a wood-based composite product with the largest market share for residential and commercial construction. OSB composite products have introduced variability in their physical and mechanical properties due to their raw material and process variation. Reliable in-line non-destructive evaluation (NDE) devices are needed to rapidly determine OSB panel product quality during and after the manufacturing process. Wood specific gravity (SG) and moisture content (MC) play an important role in the wood composite manufacturing process. A real-time after-press monitoring device for locating SG and MC variations can supply information needed to control and improve mat formation, hot press …
The Effect Of Changing Government Subsidy Programs: An Analysis Of Revenue At The Farm Level, Sarah Elizabeth Thomas
The Effect Of Changing Government Subsidy Programs: An Analysis Of Revenue At The Farm Level, Sarah Elizabeth Thomas
Theses and Dissertations
The expiration of the 2002 Farm Bill has presented an opportunity to renovate current farm policy into a program that better meets the demands faced by producers and other interested parties. During the farm bill debates on what to do with subsidy payments, the idea of structuring new programs that better fit a farmer?s needs is gaining momentum. These programs are often revenue based, adding to a more efficient program by combining yield and price risk. The intention of this thesis was to offer an overview of the potential effects of changes in farm programs on both the level and …
Simulation Of Microporosity In Aluminum Plate Castings, Enrique R. Escobar De Obaldia
Simulation Of Microporosity In Aluminum Plate Castings, Enrique R. Escobar De Obaldia
Theses and Dissertations
Porosity is known to be one of the primary factors controlling fatigue life and total elongation in cast aluminum components. The thrust of this study is to examine pore nucleation and growth effects for predicting gas microporosity in A356 plates. In this work, a solidification model is used to quantify and evaluate the discrepancy between experimental data and porosity calculated with different approaches. The first approach considers hydrogen supersaturation based on the transport of dissolved hydrogen and Sievert?s law. The second approach uses the hydrogen supersaturation calculated in the first approach combined with a local solidification time. The third approach …
T-6a Texan Ii In-Flight Simulation And Variable Stability System Design, Kenneth Paul Germann
T-6a Texan Ii In-Flight Simulation And Variable Stability System Design, Kenneth Paul Germann
Theses and Dissertations
Inlight variable stability aircraft and inlight simulation are described. The uses of these vehicles and the associated requirements are described. Several forms of control architecture are identified for use in a T-6A inlight simulator. A non-linear model of the T-6A Texan II is developed for use in MATLAB/SIMULINK®. This model is used to design a feedforward responseeedback controller, based on simplified dynamic inversion. This controller is shown to exercise precise control over the T-6A host aircraft dynamics. This architecture is then used to demonstrate simulation of the A-4 and the F-15 by the T-6A. In addition to proving simplified dynamic …
Development Of Conjugate Heat Transfer Capability To An Unstructured Flow Solver - U2ncle, Qingluan Xue
Development Of Conjugate Heat Transfer Capability To An Unstructured Flow Solver - U2ncle, Qingluan Xue
Theses and Dissertations
A precise prediction of the heat loads in metal materials in contact with the hot gas is an increasingly demanding problem in the design phase of the complex cooling schemes in the modern turbine engines. The coupled calculation of the fluid flow and the heat transfer is a promising approach as heat transfer coefficients are not necessary in the calculation and the heat transfer itself is part of the calculation and can be derived from local heat fluxes. Therefore, it is useful to incorporate an appropriate scheme for directly coupled heat transfer computations (conjugate heat transfer), capable of handling complex …
Analysis Of The Design And Operation Of Mix-Bank Resequencing Areas, Arunkumar Subramanian
Analysis Of The Design And Operation Of Mix-Bank Resequencing Areas, Arunkumar Subramanian
Theses and Dissertations
Automotive assembly plants work on a pre-planned job sequence in order to optimize the performance of the assembly line. However, the job sequence becomes scrambled due to factors such as plant layout, process design, variability and uncertainty. Assembly plants use either a mix-bank or an automatic storage and retrieval system to regenerate the sequence before final assembly. A mix-bank, which is a set of parallel lanes, is the most common method used in the automotive industry to reconstruct the sequence. Only the first vehicles on the lanes are available for sequencing in a mix-bank set-up. Hence the lane selection policy …
The Virtual Intermodal Transportation System (Vits), Aaron C. Tan
The Virtual Intermodal Transportation System (Vits), Aaron C. Tan
Theses and Dissertations
Available tools are insufficient to provide the needed systemwide view for planning future freight transportation systems based on the coordinated use of more than one mode of transportation. Many existing tools are either mode specific (they only address a single mode of transportation) or too microscopic in scope (they address only detailed traffic flows or facility operations). No comprehensive tool exists that considers the level of performance of the total system, which is important due to the many interdependencies that exist between the different modes of transportation. In some cases, optimizing just a particular component of the transportation network could …
Modified Selection Mechanisms Designed To Help Evolution Strategies Cope With Noisy Response Surfaces, Sriphani Raju Gadiraju
Modified Selection Mechanisms Designed To Help Evolution Strategies Cope With Noisy Response Surfaces, Sriphani Raju Gadiraju
Theses and Dissertations
With the rise in the application of evolution strategies for simulation optimization, a better understanding of how these algorithms are affected by the stochastic output produced by simulation models is needed. At very high levels of stochastic variance in the output, evolution strategies in their standard form experience difficulty locating the optimum. The degradation of the performance of evolution strategies in the presence of very high levels of variation can be attributed to the decrease in the proportion of correctly selected solutions as parents from which offspring solutions are generated. The proportion of solutions correctly selected as parents can be …
Computer Simulation Studies For The Production Of 7-Tetradecene By Reactive Distillation, Sandra Viviana Bennun Serrano
Computer Simulation Studies For The Production Of 7-Tetradecene By Reactive Distillation, Sandra Viviana Bennun Serrano
Theses and Dissertations
The production of 7-tetradecene was examined. Properties for this compound were estimated using group contribution methods and compared to experimental data. Process simulation was used as a tool to identify competitive processing strategies. For reactive distillation, three different models were compared to determine the model complexity needed to describe the process: Model A, with the assumption of physical and chemical equilibrium; Model B, with kinetics described by a second order reaction and physical equilibrium; and Model C, a non-equilibrium stage model that accounts for mass transfer. A conceptual design was obtained with Model B and was checked with Model C, …