Engineering Commons^™

Deep Reinforcement Learning For The Design Of Structural Topologies, Nathan Brown

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Advances in machine learning algorithms and increased computational efficiencies have given engineers new capabilities and tools for engineering design. The presented work investigates using deep reinforcement learning (DRL), a subset of deep machine learning that teaches an agent to complete a task through accumulating experiences in an interactive environment, to design 2D structural topologies. Three unique structural topology design problems are investigated to validate DRL as a practical design automation tool to produce high-performing designs in structural topology domains.

The first design problem attempts to find a gradient-free alternative to solving the compliance minimization topology optimization problem. In the proposed …

Modeling And Solution Methodologies For Mixed-Model Sequencing In Automobile Industry, Ibrahim Ozan Yilmazlar

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The global competitive environment leads companies to consider how to produce high-quality products at a lower cost. Mixed-model assembly lines are often designed such that average station work satisfies the time allocated to each station, but some models with work-intensive options require more than the allocated time. Sequencing varying models in a mixed-model assembly line, mixed-model sequencing (MMS), is a short-term decision problem that has the objective of preventing line stoppage resulting from a station work overload. Accordingly, a good allocation of models is necessary to avoid work overload. The car sequencing problem (CSP) is a specific version of the …

An Application Of Optimized Bistable Laminates As A Low Velocity, Low Impact Mechanical Deterrent, Graham Lancaster

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This research considers the problem of using bistable laminates as a mechanical deterrent to the impending impact of a particle. The structure will be controlled through an algorithm that will utilize piezoelectric devices to activate them in unison with the bistable laminate to successfully deter. A novel experimental setup will be constructed to ensure that the bistable laminate stays fixed when acting as a mechanical deterrent. Piezoelectricity is the main driving force of the bistable laminate to morph and this study will use a Macro Fiber Composite (MFC) actuator that contains piezoelectric ceramic rods in a patch to transfer electrical …

Essays On Perioperative Services Problems In Healthcare, Amogh S. Bhosekar

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One of the critical challenges in healthcare operations management is to efficiently utilize the expensive resources needed while maintaining the quality of care provided. Simulation and optimization methods can be effectively used to provide better healthcare services. This can be achieved by developing models to minimize patient waiting times, minimize healthcare supply chain and logistics costs, and maximize access. In this proposal, we study some of the important problems in healthcare operations management. More specifically, we focus on perioperative services and study scheduling of operating rooms (ORs) and management of necessary resources such as staff, equipment, and surgical instruments. We …

Multiple Objective Function Optimization And Trade Space Analysis, Yifan Xu

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Optimization can assist in obtaining the best possible solution to a design problem by varying related variables under given constraints. It can be applied in many practical applications, including engineering, during the design process. The design time can be further reduced by the application of automated optimization methods. Since the required resource and desired benefit can be translated to a function of variables, optimization can be viewed as the process of finding the variable values to reach the function maxima or minima. A Multiple Objective Optimization (MOO) problem is when there is more than one desired function that needs to …

Optimal Global Supply Chain And Warehouse Planning Under Uncertainty, Avnish Kishor Malde

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A manufacturing company's inbound supply chain consists of various processes such as procurement, consolidation, and warehousing. Each of these processes is the focus of a different chapter in this dissertation.

The manufacturer depends on its suppliers to provide the raw materials and parts required to manufacture a finished product. These suppliers can be located locally or overseas with respect to the manufacturer's geographic location. The ordering and transportation lead times are shorter if the supplier is located locally. Just In Time (JIT) or Just In Sequence (JIS) inventory management methods could be practiced by the manufacturer to procure the raw …

Hierarchical And Distributed Architecture For Large-Scale Residential Demand Response Management, Pramod Herath Mudiyanselage

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The implementation of smart grid brings several challenges to the power system. The ‘prosumer’ concept, proposed by the smart grid, allows small-scale ‘nano-grids’ to buy or sell electric power at their own discretion. One major problem in integrating prosumers is that they tend to follow the same pattern of generation and consumption, which is un-optimal for grid operations. One tool to optimize grid operations is demand response (DR). DR attempts to optimize by altering the power consumption patterns. DR is an integrated tool of the smart grid. FERC Order No. 2222 caters for distributed energy resources, including demand response resources, …

Development Of A Reverse Engineered, Parameterized, And Structurally Validated Computational Model To Identify Design Parameters That Influence American Football Faceguard Performance, William Ferriell

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Traumatic brain injury (TBI) continues to have the greatest incidence among athletes participating in American football. The headgear design research community has focused on developing accurate computational and experimental analysis techniques to better assess the ability of headgear technology to attenuate impacts and protect athletes from TBI. Despite efforts to innovate the headgear system, minimal progress has been made to innovate the faceguard. Although the faceguard is not the primary component of the headgear system that contributes to impact attenuation, faceguard performance metrics, such as weight, structural stiffness, and visual field occlusions, have been linked to athlete safety. To improve …

Interdiction Models To Disrupt The Operations Of Sex Trafficking And Other Forced Illicit Labor Networks, Michael T. Clark

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Sex traffickers often force their victims to work in both commercial sex markets and perform other illicit activities (e.g., drug dealing, theft, and fraud). Current literature has failed to address interdiction models that aim to disrupt all components of a sex traffickers’ operation, including these other illicit activities. In this thesis, we present a interdiction problem, and its single-level linear optimization reformulation, to reduce the profit of a human trafficking network concurrently operating in the commercial sex market and other illicit activity markets. Our novel formulation aims to investigate the practical implications of interdiction decisions made to disrupt a human …

Investigations Of External Resources And The Impact Of Imaging On Patient Flow In The Emergency Department, Marisa Shehan

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The problems associated with Emergency Department (ED) crowding are numerous, varied, and complex. Though overcrowded Emergency Departments are frequently attributed to overcrowded hospitals, crowding is also impacted by bottlenecks in patient flow. While discrete-event simulation (DES) is commonly used to model ED flow, external resources are typically excluded from these models due to their complexity and the limited amount of known information for these processes. Instead, external resources such as consults, labs, and imaging are modeled using estimation and/or educated guesswork. In this study, the impact of imaging on patient flow was assessed through data analysis of specific imaging factors, …

Strategies To Improve The Efficiency Of Emergency Medical Service (Ems) Systems Under More Realistic Conditions, Kanchala Sudtachat

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Emergency medical service (EMS) systems provide medical care to pre-hospital patients who need rapid response and transportation. This dissertation proposes a new realistic approach for EMS systems in two major focuses: multiple unit dispatching and relocation strategies. This work makes recommendations for multiple-unit dispatch to multiple call priorities based on simulation optimization and heuristics. The objective is to maximize the expected survival rate. Simulation models are proposed to determine the optimization. A heuristic algorithm is developed for large-scale problems. Numerical results show that dispatching while considering call priorities, rather than always dispatching the closest medical units, could improve the effectiveness …

Identifying Target Properties For The Design Of Meta-Material Tank Track Pads, Venkata Sampath Dangeti

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On track vehicle systems, track pads are designed to provide traction and support the weight of the vehicle, they have limited service life due to common failure by blowout. According to the literature, blowout is a failure mode caused by overheating due to hysteresis in elastomeric materials during high speed operations. Elastomers are used primarily for their high compliance, which is essential to protect the suspension components and maintain structural integrity of the track pad. The objective of the work is to explore the use of linear elastic meta-materials with optimized topology to replace elastomers and reduce or eliminate the …

Predictive Maturity Of Inexact And Uncertain Strongly Coupled Numerical Models, Ismail Farajpour

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The Computer simulations are commonly used to predict the response of complex systems in many branches of engineering and science. These computer simulations involve the theoretical foundation, numerical modeling and supporting experimental data, all of which contain their associated errors. Furthermore, real-world problems are generally complex in nature, in which each phenomenon is described by the respective constituent models representing different physics and/or scales. The interactions between such constituents are typically complex in nature, such that the outputs of a particular constituent may be the inputs for one or more constituents. Thus, the natural question then arises concerning the validity …

Cost And Embodied Energy Optimization Of Rectangular Reinforced Concrete Beams, Alexander Kosloski

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Concrete has a large environmental footprint so it is desirable to find ways to efficiently design structural members. Engineers can exercise their abilities early on in the design phase of construction projects to reduce the environmental footprint by minimizing the amount of materials required. One way to achieve these results is to optimize the design of structural concrete. In this study, simple-span rectangular reinforced concrete (RC) beams with a range of different bending moments were analyzed. The primary goal was to combine life cycle analysis (LCA), numerical optimization, and reinforced concrete mechanics to create a framework for designing efficient RC …

Optimization Of Porous Pavement Mixtures Based On Aggregate Structure, Andrew Neptune

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Porous pavements are sustainable features that are used to help manage the quantity and quality of stormwater runoff. These pavements may include porous asphalt, permeable interlocking concrete pavers and pervious concrete. Since pavements that are purposefully designed to drain water through their matrix are relatively new, contractors and engineers are faced with various challenges such as improper design and installation, poor workability, and excessive finishing which may lead to clogged pores. Therefore, this study on porous pavements examined pervious concrete mixtures to evaluate an optimization process for the preparation of porous pavement mixtures based on aggregate structure to meet desired …

Stochastic Tools For Network Security: Anonymity Protocol Analysis And Network Intrusion Detection, Lu Yu

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With the rapid development of Internet and the sharp increase of network crime, network security has become very important and received a lot of attention.
In this dissertation, we model security issues as stochastic systems. This allows us to find weaknesses in existing security systems and propose new solutions. Exploring the vulnerabilities of existing security tools can prevent cyber-attacks from taking advantages of the system weaknesses. We consider The Onion Router (Tor), which is one of the most popular anonymity systems in use today, and show how to detect a protocol tunnelled through Tor. A hidden Markov model (HMM) is …

Connecting Architecture, Fitness, Optimizations And Performance Using An Anisotropic Diffusion Filter, Sumedh Naik

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Over the past decade, computing architectures have continued to exploit multiple levels of parallelism in applications. This increased interest in parallel computing has not only fueled the growth of multi-core processors but has also lead to an emergence of several non-traditional computing architectures like General Purpose Graphical Processing Units (GP-GPUs), Cell Processors, and Field Programmable Gate Arrays (FPGAs). Of these non-traditional computing architectures, GP-GPUs have gained widespread popularity due to their massively parallel computational abilities and relative ease of programmability.
Several software development ecosystems have emerged to harness the power of these parallel architectures. Although several threading libraries like POSIX …

Design Of Meta-Materials Outside The Homogenization Limit Using Multiscale Analysis And Topology Optimization, Christopher Czech

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The field of meta-materials engineering has largely expanded mechanical design possibilities over the last two decades; some notable design advances include the systematic engineering of negative Poisson's ratio materials and functionally graded materials, materials designed for optimal electronic and thermo-mechanical performances, and the design of materials under uncertainty. With these innovations, the systematic engineering of materials for design-specific uses is becoming more common in industrial and military uses. The motivation for this body of research is the design of the shear beam for a non-pneumatic wheel. Previously, a design optimization of a finite element model of the non-pneumatic wheel was …

A New Metaheuristic Algorithm Motivated By The Rooting Phenomena In Plants, Behzad Nemati

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In this thesis, we present a new metaheuristic algorithm for analyzing challenging optimization problems. Initial testing reveals the potential for the algorithm, which is based on the rooting phenomena found in plants in nature, to quickly produce effective solutions to challenging combinatorial optimization problems in the class NP. We present computational results describing the proposed metaheuristic's efficacy for an important class of scheduling problems and discuss areas of future work and application.

Modeling, Finite Element Analysis, And Optimization Of Non-Pneumatic Tire (Npt) For The Minimization Of Rolling Resistance, Mallikarjun Veeramurthy

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Recently, the development of non-pneumatic tires (NPT) such as the Michelin Tweel is receiving increased attention due to potential advantages over pneumatic tires such as low mass, no run flat, good contact pressure distribution, and low rolling resistance (RR). This study focuses on the design of a NPT based on properties of vertical stiffness, contact pressure, and rolling energy loss. Using a finite element (FE) model, a parametric study is conducted to study the effect on vertical stiffness, contact pressure, and rolling resistance (RR) response considering three design variables: (1) thickness of the spokes, (2) the shear band thickness, and …

Requirements Determination Of A Novel Non-Pneumatic Wheel Shear Beam For Low Rolling Resistance, Niranjan Thyagaraja

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The hysteretic loss associated with cyclic shear in the elastomeric shear layer is one of the prevailing concerns for the development of a low rolling loss non-pneumatic wheel. We propose to eliminate the hysteretic losses associated with the elastomeric shear layer and thus, reduce the corresponding rolling resistance by using linear elastic materials which are inherently non-hysteretic. Since the shear modulus of a viscoelastic shear layer is less than that of an elastic material by several orders of magnitude, the challenge to achieve a low effective shear modulus shear layer with linear elastic materials directs towards the development of a …

Agent-Based Under Hood Packing, Karthik Ravindranath

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Improving vehicle performance and passenger comfort has been a prime engineering concern and focus of research for many years in automotive design. Turning to high-performance components in an effort to improve vehicle performance alone is often not enough and their placement and interactions with other components should also be an integral part of the improvement process. With the advancement in hybrid electric vehicle technology, the packing of components under the hood is ever more essential and challenging. Under hood packing is a multi-objective optimization problem with many, and mostly conflicting objectives. A non-deterministic multi-objective evolutionary algorithm needs to be integrated …

Determining The Global Maximum Biofuel Production Potential Without Conflicting With Food And Feed Consumption, Watcharapol Pumkaew

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This study tries to resolve the competition between food and biofuel by balancing the allocation between food and feed areas and biofuel areas for the entire world. The maximum energy production is calculated by determining the theoretical amount of energy that can be grown, once food and feed consumption is taken into account, based on the assumption that unprotected grass and woody lands and forest lands can be converted into cultivated lands. The total optimum land area for biofuel energy, 4,926.49 Mha, consists of corn, rapeseed, sugar beet, sugar cane, and grasses. When considering energy conversion efficiency, the maximum energy …

Development And Integration Of Geometric And Optimization Algorithms For Packing And Layout Design, Santosh Tiwari

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The research work presented in this dissertation focuses on the development and application of optimization and geometric algorithms to packing and layout optimization problems. As part of this research work, a compact packing algorithm, a physically-based shape morphing algorithm, and a general purpose constrained multi-objective optimization algorithm are proposed. The compact packing algorithm is designed to pack three-dimensional free-form objects with full rotational freedom inside an arbitrary enclosure such that the packing efficiency is maximized. The proposed compact packing algorithm can handle objects with holes or cavities and its performance does not degrade significantly with the increase in the complexity …

Synthesis Of Optimal Usage Of Available Aggregates In Highway Construction And Maintenance, Benjamin Skidmore

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The optimization of the available aggregates for highway construction and maintenance is vital both from an economic and environmental perspective. By not optimizing the aggregate supply project costs escalate as a simple response to supply and demand, and just as important the fact that aggregate is a natural resource and a limited one, it is crucial that is used as efficiently as possible. This paper examines specifically the use of aggregates by the South Carolina Department of Transportation, but can easily be adapted to any state. Through DOT and quarry surveys and an examination of aggregate gradation specifications it was …

Optimization And Characterization Of Biodiesel Production From Cottonseed And Canola Oil, Hem Joshi

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Transesterification of cottonseed oil and canola oil was carried out using low molecular weight alcohols and potassium hydroxide. For cottonseed oil, a central composite design with eight factorial, six center and six axial points was used to study the effect of catalyst concentration, molar ratio of ethanol to cottonseed oil and reaction temperature on percentage yield and percentage initial absorbance (%A385nm) of the biodiesel. Catalyst concentration and molar ratio of ethanol to cottonseed oil were the most influential variables affecting percentage conversion and percentage initial absorbance. Maximum percentage yield of 98 % is predicted at a catalyst concentration of 1.07 …

Biohydrogen Production By The Hyperthermophilic Bacterium Thermotoga Neapolitana, Xiaohui Yu

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ABSTRACT Thermotoga neapolitana can use different sources of carbon and nitrogen for growth and produces biological hydrogen. Sources of carbon (glucose, sucrose, xylose, xylan, cellulose, cellobiose, starch, corn starch, beet bulp pellet, and rice flour) and nitrogen (yeast extract, fish meal, cottonseed meal, canola meal, linseed meal, and soybean meal) were compared. In the carbon studies, glucose, sucrose, rice flour, and xylan produced similar levels of hydrogen. In the nitrogen studies, Trypticase combined with alternative nitrogen sources can efficiently increases the yield of hydrogen produced by Thermotoga neapolitana. Yeast extract with trypticase as the dual nitrogen sources produced significantly increased …

Optimal Placement Of Metal Foils In Ultrasonic Consolidation Process, Raji Rexavier

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Ultrasonic Consolidation is a combination of additive and subtractive
manufacturing processes resulting in considerable material waste. This waste is a
function of the geometry of the part being manufactured and of the relative
placement of the layer with respect to the metal bands. Thus the waste may be
minimized by careful choice of the layer angle and offset from the original
position.
Previous work done in this field had developed an automated algorithm which
optimally places and orients the individual slices of the STL file of the artifact
being manufactured. However, the problem was solved on a 2-D scale and …