Engineering Commons^™

Optimization And Control Of Arrays Of Wave Energy Converters, Jianyang Lyu

Dissertations, Master's Theses and Master's Reports

Wave Energy Converter Array is a practical approach to harvest ocean wave energy. To leverage the potential of the WEC array in terms of energy extraction, it is essential to have a properly designed array configuration and control system. This thesis explores the optimal configuration of Wave Energy Converters (WECs) arrays and their optimal control. The optimization of the WEC array allows both dimensions of individual WECs as well as the array layout to varying. In the first optimization problem, cylindrical buoys are assumed in the array where their radii and drafts are optimization parameters. Genetic Algorithms are used for …

Foundations For A Game Theoretic Framework For Agile Acquisition, Scott Rosen, Kelly Horinek, Alexander Odeh, Les Servi, Andreas Tolk

VMASC Publications

This article investigates the concept of developing a game theoretic framework that is based on the application of buyer and seller utility functions to support the bidding process in government acquisition. The results of a literature survey of utility function approaches, with potential to provide a suitable foundation to a game theory framework for acquisition, are presented. The utility function methods found most promising were further adapted and tested: the Best-Worst method, the Multi-Swing Method, and Functional Dependency for Network Analysis. To test the scalability of the approach, the Best-Worst method is applied to a larger problem to show the …

Marine Quay Crane Scheduling Using A Combined Modified Genetic Algorithm And Priority Rules Approach, V. H. Nguyen, D. T. Nguyen

Civil & Environmental Engineering Faculty Publications

Quay crane scheduling problem (QCSP) is the problem of the allocation of quay cranes to handle the unloading and loading of containers at seaport container terminals and defining the service sequence of vessel bays of each quay crane. The treatment of crane interference constraints and the increased in vessel size make the problem difficult to solve. Due to the growing interest in applied research for this problem, many researchers have used different algorithms and methods to obtain some solutions. This paper will propose a modified genetic algorithm combined with priority rules to deal with it. The advantage of the proposed …

Applications Of A New Genetic Algorithm To Solve The Centralized Carrier Collaboration And Multihub Location Problem Considering Environmental Impacts, Eduardo Jose Castillo Fatule

Open Access Theses & Dissertations

The Centralized Carrier Collaboration and Multi-hub Location Problem (CCCMLP) represents a strategy that small-to-medium sized less-than-truckload (LTL) carrier companies can use in order to improve their profit margins. It is a strategy that is being explored in order to make these companies more sustainable as they are forced to reinvent their processes and supply chains. In this work, I will present a metaheuristic approach to optimizing their hub establishment and routing policies in order to better their expected profit margins and reduce their environmental impacts. The study considers the costs of transportation, loading and unloading, maintenance, operations, and inventory holding …

Non-Deterministic Metamodeling For Multidisciplinary Design Optimization Of Aircraft Systems Under Uncertainty, Daniel L. Clark Jr.

Browse all Theses and Dissertations

To make coupled multi-physics-informed design decisions, multidisciplinary analysis, design optimization and uncertainty quantification must be present to accurately represent the full system under investigation. Unfortunately, all of these processes are computationally demanding, requiring a large number of system evaluations with identified uncertain variables, and iterative system evaluations with respect to the design variables of interest. Surrogate or metamodels are used to alleviate the computational burden in both these design exploration activities by trading accuracy with efficiency. The primary objective of this dissertation is to develop a flexible surrogate modeling technique capable of quantifying the uncertainty of multidisciplinary systems in an …

Curricular Optimization: Solving For The Optimal Student Success Pathway, William G. Thompson-Arjona

Theses and Dissertations--Electrical and Computer Engineering

Considering the significant investment of higher education made by students and their families, graduating in a timely manner is of the utmost importance. Delay attributed to drop out or the retaking of a course adds cost and negatively affects a student’s academic progression. Considering this, it becomes paramount for institutions to focus on student success in relation to term scheduling.

Often overlooked, complexity of a course schedule may be one of the most important factors in whether or not a student successfully completes his or her degree. More often than not students entering an institution as a first time full …

Optimum Design Of Axial Flux Pm Machines Based On Electromagnetic 3d Fea, Narges Taran

Theses and Dissertations--Electrical and Computer Engineering

Axial flux permanent magnet (AFPM) machines have recently attracted significant attention due to several reasons, such as their specific form factor, potentially higher torque density and lower losses, feasibility of increasing the number of poles, and facilitating innovative machine structures for emerging applications. One such machine design, which has promising, high efficiency particularly at higher speeds, is of the coreless AFPM type and has been studied in the dissertation together with more conventional AFPM topologies that employ a ferromagnetic core.

A challenge in designing coreless AFPM machines is estimating the eddy current losses. This work proposes a new hybrid analytical …

Optimization Of Process Parameters And Fermentation Strategy For Xylanase Production In A Stirred Tank Reactor Using A Mutant Aspergillus Nidulans Strain, Asmaa Abdella, Fernando Segato, Mark R. Wilkins

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The present work studied the optimization of aeration rate, agitation rate and oxygen transfer and the use of various batch fermentation strategies for xylanase production from a recombinant Aspergillus nidulans strain in a 3 L stirred tank reactor. Maximum xylanase production of 1250 U/mL with productivity of 313 U/mL/day was obtained under an aeration rate of 2 vvm and an agitation rate of 400 rpm using batch fermentation. The optimum volumetric oxygen transfer coefficient (kLa) for efficient xylanase production was found to be 38.6 h1. Fed batch mode and repeated batch fermentation was also performed with kLa was 38.6 h1. …

Optimization Of Process Parameters And Fermentation Strategy For Xylanase Production In A Stirred Tank Reactor Using A Mutant Aspergillus Nidulans Strain, Asmaa Abdella, Fernando Segato, Mark R. Wilkins

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The present work studied the optimization of aeration rate, agitation rate and oxygen transfer and the use of various batch fermentation strategies for xylanase production from a recombinant Aspergillus nidulans strain in a 3 L stirred tank reactor. Maximum xylanase production of 1250 U/mL with productivity of 313 U/mL/day was obtained under an aeration rate of 2 vvm and an agitation rate of 400 rpm using batch fermentation. The optimum volumetric oxygen transfer coefficient (kLa) for efficient xylanase production was found to be 38.6 h-1. Fed batch mode and repeated batch fermentation was also performed with kLa was 38.6 h …

Designing An On-Demand Dynamic Crowdshipping Model And Evaluating Its Ability To Serve Local Retail Delivery In New York City, Shirin Najaf Abadi

Dissertations and Theses

Nowadays city mobility is challenging, mainly in populated metropolitan areas. Growing commute demands, increase in the number of for-hire vehicles, enormous escalation in several intra-city deliveries and limited infrastructure (road capacities), all contribute to mobility challenges. These challenges typically have significant impacts on residents’ quality-of-life particularly from an economic and environmental perspective. Decision-makers have to optimize transportation resources to minimize the system externalities (especially in large-scale metropolitan areas). This thesis focus on the intra-city mobility problems experienced by travelers (in the form of congestion and imbalance taxi resources) and businesses (in the form of last-mile delivery), while taking into consideration …

Time-Dependent Reliability Methodologies With Saddlepoint Approximation, Zhangli Hu

Doctoral Dissertations

"Engineers always encounter time-dependent uncertainties that ubiquitously exist, such as the random deterioration of material properties and time-variant loads. Therefore the reliability of engineering systems becomes time-dependent. It is crucial to predict the time-dependent reliability in the design stage, given possible catastrophic consequences of a failure. Although extensive research has been conducted on reliability analysis, estimating the reliability accurately and efficiently is still challenging. The objective of this work is to develop accurate and efficient reliability methodologies for engineering design. The basic idea is the integration of traditional reliability methods with saddlepoint approximation (SPA), which can accurately approximate the tail …

Techno-Economic Optimization And Environmental Life Cycle Assessment Of Microgrids Using Genetic Algorithm And Artificial Neural Networks, Prashant Nagapurkar

Doctoral Dissertations

"This dissertation focuses primarily on techno-economic optimization and environmental life cycle assessment (LCA) of sustainable energy generation technologies. This work is divided into five papers. The first paper discusses the techno-economic optimization and environmental life cycle assessment of microgrids located in the USA using genetic algorithm. In this paper, a methodology was developed that assessed the techno-economic and environmental performance of a small scale microgrid located in US cities of Tucson, Lubbock and Dickinson. Providing uninterrupted power the microgrid was composed of seven components -- solar photovoltaics, wind-turbines, lead acid batteries, biodiesel generators, fuel cells, electrolyzers and H₂ tanks. …

Renewables-Integrated Internal Combustion Engine-Based Multi-Generation Options For Uab Buildings, Qing Mu

All ETDs from UAB

Distributed energy, also district or decentralized energy is generated or stored by a variety of small, grid-connected devices referred to as distributed energy resources, or distributed energy resource systems. The Distributed Generation (DG) systems can increase energy system reliability, reduce peak power requirements, and improve energy infrastructure resilience. In this study, a DG system using renewable energy sources and energy storage has been introduced for the whole University of Alabama at Birmingham (UAB) campus. The energy sources for this DG system are photovoltaic arrays, a natural-gas-powered Internal Combustion Engine (ICE), and wind turbines. The energy storage component used in this …

A Statistical Approach To Provide Explainable Convolutional Neural Network Parameter Optimization, Saman Akbarzadeh, Selam Ahderom, Kamal Alameh

Research outputs 2014 to 2021

Algorithms based on convolutional neural networks (CNNs) have been great attention in image processing due to their ability to find patterns and recognize objects in a wide range of scientific and industrial applications. Finding the best network and optimizing its hyperparameters for a specific application are central challenges for CNNs. Most state-of-the-art CNNs are manually designed, while techniques for automatically finding the best architecture and hyperparameters are computationally intensive, and hence, there is a need to severely limit their search space. This paper proposes a fast statistical method for CNN parameter optimization, which can be applied in many CNN applications …

Design And Fabrication Of A Dual-Polarized, Dual-Band Reflectarray Using Optimal Phase Distribution, Iman Aryanian, Arash Ahmadi, Mehdi Rabbani, Sina Hassibi, Majid Karimipour

Turkish Journal of Electrical Engineering and Computer Sciences

Two main factors limiting the reflectarray bandwidth are different phase slopes versus the frequency at every point on the aperture and the phase limitation of comprising elements at different frequencies. Considering these two factors, a novel design method is proposed to implement a dual-band, dual-polarized reflectarray antenna in X and Ku bands. An optimization algorithm is adopted to find the optimum phase for each unit cell on the reflectarray aperture. The best geometrical parameters of the phasing elements are suggested based on the phase variation of the element versus frequency and the element position with respect to the antenna feed. …

Optimal Training And Test Sets Design For Machine Learning, Burkay Genç, Hüseyi̇n Tunç

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, we describe histogram matching, a metric for measuring the distance of two datasets with exactly the same features, and embed it into a mixed integer programming formulation to partition a dataset into fixed size training and test subsets. The partition is done such that the pairwise distances between the dataset and the subsets are minimized with respect to histogram matching. We then conduct a numerical study using a well-known machine learning dataset. We demonstrate that the training set constructed with our approach provides feature distributions almost the same as the whole dataset, whereas training sets constructed via …

Performance Comparison Of Optimization Algorithms In Lqr Controller Design For A Nonlinear System, Ümi̇t Önen, Abdullah Çakan, İlhan İlhan

Turkish Journal of Electrical Engineering and Computer Sciences

The development and improvement of control techniques has attracted many researchers for many years. Especially in the controller design of complex and nonlinear systems, various methods have been proposed to determine the ideal control parameters. One of the most common and effective of these methods is determining the controller parameters with optimization algorithms.In this study, LQR controller design was implemented for position control of the double inverted pendulum system on a cart. First of all, the equations of motion of the inverted pendulum system were obtained by using Lagrange formulation. These equations were linearized by Taylor series expansion around the …

Evolutionary Approaches For Weight Optimization In Collaborative Filtering-Based Recommender Systems, Sevgi̇ Yi̇ği̇t Sert, Yilmaz Ar, Gazi̇ Erkan Bostanci

Turkish Journal of Electrical Engineering and Computer Sciences

Collaborative filtering is one of the widely adopted approaches in recommender systems used for e-commerce applications, stating that users having similar tastes will have similar preferences in the future. The literature presents a number of similarity metrics such as the extended Jaccard coefficient to quantify these preference similarities. This paper aims to improve prediction accuracy by optimizing the similarity values computed using these metrics by adopting two biologically inspired approaches, namely artificial bee colony and genetic algorithms, with a bottom-up approach, suggesting that any improvement on a single-user basis will reflect on the overall prediction accuracy. Detailed statistical analysis was …

A New Approach For Wind Turbine Placement Problem Using Modified Differential Evolution Algorithm, Hüseyi̇n Hakli

Turkish Journal of Electrical Engineering and Computer Sciences

Energy use is increasing worldwide with industrialization and advancing technology. Following this increase, renewable energy resources are increasingly preferred to reduce the costs of energy production. Wind energy is preferred as a renewable energy resource because it is clean and safe. Wind turbines are used to meet the demand for wind energy. They are placed close to each other to generate higher amounts of energy. However, the wake effect problem arises in these types of layouts, and this hinders the turbines from producing the desired yield. A modified differential evolution (MDE) algorithm was proposed in this study to solve the …

The Effect Of Communication And Vehicle Properties On The Search Performance Of A Swarm Of Unmanned Aerial Vehicles, Jenna E. Newcomb, Andrew Ning

Faculty Publications

An unmanned aerial vehicle (UAV) swarm allows for a more time-efficient method of searching a specified area than a single UAV or piloted plane. There are a variety of factors that affect how well an area is surveyed. We specifically analyzed the effect both vehicle properties and communication had on the swarm search performance. We used non-dimensionalization to examine the effect vehicle properties had on search performance so the results can be applied to any domain size with any number and type of vehicle. We found that even if vehicles could only sense 10% of the grid area at any …

A Sustainable Prototype For Renewable Energy: Optimized Prime-Power Generator Solar Array Replacement, Nathan Thomsen, Torrey J. Wagner, Andrew J. Hoisington, Steven J. Schuldt

Faculty Publications

Remote locations such as disaster relief camps, isolated arctic communities, and military forward operating bases are disconnected from traditional power grids forcing them to rely on diesel generators with a total installed capacity of 10,000 MW worldwide. The generators require a constant resupply of fuel, resulting in increased operating costs, negative environmental impacts, and challenging fuel logistics. To enhance remote site sustainability, planners can develop stand-alone photovoltaic-battery systems to replace existing prime power generators. This paper presents the development of a novel cost-performance model capable of optimizing solar array and Li-ion battery storage size by generating tradeoffs between minimizing initial …

Optimization Of Data Processing Based On Accounting For Factors Of External Expenses, Regulation And Correction Of Variables ., I.I Jumanov, S.M Xolmonov

Chemical Technology, Control and Management

Methods and simplified computational schemes for optimizing data processing for systems operating in conditions of limited a priori information, changes in the characteristics of external influences, uncertainty of parameters have been developed. To describe a non-stationary object, non-linear identification models are considered, constraints, input conditions for obtaining possible values of output variables are defined. An approach aimed at using identification technologies based on generalization of capabilities of dynamic models, neural networks (NN), mechanisms for regulating variable computing schemes of structural network components, as well as learning algorithms of the NN is proposed. A generalized algorithm for learning NN based on …

Optimization Of The Process Of Functioning Of Multiservice Networks ., A.R Marakhimov, G.B Sherboboyeva

Chemical Technology, Control and Management

In order to optimize the delay time of information flows in the nodes, multiservice networks propose the application of the theory of fuzzy sets, with the help of which models are developed for calculating the delay time, taking into account the inaccuracy of time, simple, correct operation and aging of information. A fuzzy model for calculating the average message delay time through communication nodes in multiservice networks is given, with each channel of switching nodes being modeled as a queuing network. A single-criterion problem of the optimal distribution of information flows over the channels of switching nodes with ill-defined data …

Parametric Design And Optimization Of A Pivoting S-Type Rudder For Containerships, Chen-Wei Chen, Tsung-Yueh Lin, Bo-Yen Chen, Jen-Shiang Kouh

Journal of Marine Science and Technology–Taiwan

This study proposes an energy-saving S-type rudder design to deal with the inhomogeneous inflow from a rotating propeller behind a containership. The S-type rudder was modelled parametrically using four-digit NACA foils as section profiles together with Non-uniform rational B-splines (NURBS) surface formulations. A three-stage optimization process is proposed to reduce the number of design iterations necessary to achieve an optimal design. The propulsion simulations were done via CFD software, which solves the hydrodynamics of viscous flow, as governed by the Reynold-averaged Navier-Stokes (RANS) equations. Validations were performed with experimental model tests, including hull resistance, propeller open-water performance, and propulsion in …

An Analytical Design Of Experiments Method For Fatigue Constrained Design Optimization Of A 3d Printed Structure, Ashish Pokharel

Mechanical and Aerospace Engineering Theses - Archive

A design of experiments approach has been used to analytically determine a low cycle fatigue (LCF) constraint for use in design optimization of 3D printed structures. In context of metal additive manufacturing, the process of melting, solidification and consolidation of metal powder introduces very high temperature gradient field within the build which in turn results in high compressive stresses at the core and tensile stresses at the outer surface of the part after it has cooled down to room temperature post build. An approach of finite element modeling in ANSYS Additive has been used to develop a residual stress profile …

Internal Deformation Measurements And Optimization Of Synthetic Vocal Fold Models, Cassandra Jeanne Taylor

Theses and Dissertations

Developing lifelike vocal fold models is challenging due to various associatedbiomechanical complexities. Nevertheless, the development and analysis of improved vocal foldmodels is worthwhile since they are valuable tools for gaining insight into human vocal foldvibratory, aerodynamic, and acoustic response characteristics. This thesis seeks to contribute tothe development of computational and physical vocal fold modeling in two ways. First is byintroducing a method of obtaining internal deformation fields within vibrating synthetic vocal foldmodels; second is by presenting an optimization algorithm coupled with a computational vocalfold model to optimize geometry and stiffness of a synthetic vocal fold model to achieve morerealistic vibration …

Large-Scale Non-Linear Dynamic Optimization For Combining Applications Of Optimal Scheduling And Control, Logan Daniel Beal

Theses and Dissertations

Optimization has enabled automated applications in chemical manufacturing such as advanced control and scheduling. These applications have demonstrated enormous benefit over the last few decades and continue to be researched and refined. However, these applications have been developed separately with uncoordinated objectives. This dissertation investigates the unification of scheduling and control optimization schemes. The current practice is compared to early-concept, light integrations, and deeper integrations. This quantitative comparison of economic impacts encourages further investigation and tighter integration. A novel approach combines scheduling and control into a single application that can be used online. This approach implements the discrete-time paradigm from …

Optimization-Based Spatial Positioning And Energy Management For Unmanned Aerial Vehicles, Ronald Abraham Martin

Theses and Dissertations

This research applies techniques from the field of optimization to spatial positioning and energy management in Unmanned Aerial Vehicles (UAVs). Two specific areas are treated: optimization of UAV view plans for 3D modeling of infrastructure, and trajectory optimization of solar powered high-altitude long-endurance (HALE) UAVs. Structure-from-Motion (SfM) is a computer vision technique for creating 3D models from 2D images. View planning is the process of planning image sets that will effectively model a given scene. First, a genetic algorithm based view planning approach is demonstrated. A novel terrain simulation environment is developed, and the algorithm is tested at multiple sites …

Numerical Simulation And Optimization Of Blalock-Taussig Shunt, Thomas Hess, Ramesh K. Agarwal

McKelvey School of Engineering Graduate Student Theses & Dissertations

The goal of this study is to create an optimized Blalock-Taussig shunt used to temporarily repair pulmonary vascular blockages allowing a child time to grow so a more permanent surgical repair of the heart and vasculature can be performed. Blalock-Taussig or BT shunts are a surgical procedure performed on infants suffering from cyanosis or “Blue Baby Syndrome.” A BT shunt is an artificial vessel placed between the right ventricle and the pulmonary artery to increase blood flow in the lung and blood oxygen saturation levels. In a study of 96 patients with currently in use modified BT shunts, 32 patients …

Best Trade-Off Point Method For Efficient Resource Provisioning In Spark, Peter P. Nghiem

Computer Science and Engineering

Considering the recent exponential growth in the amount of information processed in Big Data, the high energy consumed by data processing engines in datacenters has become a major issue, underlining the need for efficient resource allocation for more energy-efficient computing. We previously proposed the Best Trade-off Point (BToP) method, which provides a general approach and techniques based on an algorithm with mathematical formulas to find the best trade-off point on an elbow curve of performance vs. resources for efficient resource provisioning in Hadoop MapReduce. The BToP method is expected to work for any application or system which relies on a …