Engineering Commons^™

An Optimal Dynamic Inversion Approach For Controlling A Class Of One-Dimensional Nonlinear Distributed Parameter Systems, Radhakant Padhi, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Combining the principles of dynamic inversion and optimization theory, a new approach is presented for stable control of a class of one-dimensional nonlinear distributed parameter systems, assuming the availability a continuous actuator in the spatial domain. Unlike the existing approximate-then-design and design-then-approximate techniques, here there is no need of any approximation either of the system dynamics or of the resulting controller. Rather, the control synthesis approach is fairly straight-forward and simple. The controller formulation has more elegance because we can prove the convergence of the controller to its steady state value. To demonstrate the potential of the proposed technique, a …

Robust Shape Design Techniques For Steady-State Metal Forming Processes, Jalaja Repalle

Browse all Theses and Dissertations

Metal forming is a process that transforms a simple shape of a workpiece into a predetermined complex shape through the application of compressive/tensile forces exerted by dies. In the design of a forming process, the only factors that are known are the final component shape and the material with which it is to be made. Then the engineer has to design a process to make defect-free product, subject to limitations of shape, material properties, cost, time, and other such factors. The design cycle can be enhanced if performance sensitivity information is available that could be used with any commercially available …

A Comparison Of Agent-Based Optimization Approaches Applied To The Weapons To Targets Assignment Planning Problem, Hitesh Deepak Soneji

Browse all Theses and Dissertations

Real-world complex optimization problems are difficult to solve. Agent-based optimization approaches have proved useful in solving a wide variety of problems including optimization problems. Agent-based techniques can be used in military planning for solving allocation problems such as the weapons to targets assignment problem. Classical methods like linear programming (LP) have been used for solving weapons to targets assignment problems. LP approaches provide optimal solutions quickly, but in real-time planning when there are minor changes to input, LP exhibits widely varied solutions. This can be a problem in practice. This research study considers two agent-based optimization approaches, the Stable Marriage …

Topology Optimization Of Engine Exhaust-Washed Structures, Mark A. Haney

Browse all Theses and Dissertations

Aircraft structure subjected to elevated temperature and acoustic loading present a challenging design environment. Thermal stress in a structural component has typically been alleviated by allowing thermal expansion. However, very little work has been done which directly addresses the situation where such a prescription is not possible. When a structural component has failed due to thermally-induced tensile stresses, the answer to the question of how best to stiffen the structure is far from trivial. In this work, we demonstrate that conventional stiffening techniques, for example, those which add material to the thickness of a failing panel, may actually increase the …

Modeling Of Capacitor Impedance In Switching Converters, Jonathan W. Kimball, Philip T. Krein, Kevin R. Cahill

Electrical and Computer Engineering Faculty Research & Creative Works

Switched capacitor (SC) converters are gaining acceptance as alternatives to traditional, inductor-based switching power converters. Proper design of SC converters requires an understanding of all loss sources and their impacts on circuit operation. In the present work, an equivalent resistance method is developed for analysis, and equivalent resistance formulae are presented for various modes of operation. Quasiresonant converters are explored and compared to standard SC converters. Comparisons to inductor-based switching power converters are made. A number of capacitor technologies are evaluated and compared for applications to both SC converters and inductor-based converters. The resulting model can be used to accurately …

Percolation In Two-Dimensional Grain Boundary Structures And Polycrystal Property Closures, David T. Fullwood

Theses and Dissertations

The thesis addresses two topics in the study of material properties as determined by the microstructure. The first topic involves percolation as a tool in relating the grain boundary structure to global properties such as fracture and corrosion resistance. The second investigates optimization techniques in order to find the space of values that properties of a material can take, from consideration of the microstructure. In part I, the applicability of standard lattice percolation models to a random 2-D grain structure is explored. A random network based on the triangle lattice is proposed as a more appropriate model, and results in …

H-Infinity Estimation For Fuzzy Membership Function Optimization, Daniel J. Simon

Electrical and Computer Engineering Faculty Publications

Given a fuzzy logic system, how can we determine the membership functions that will result in the best performance? If we constrain the membership functions to a specific shape (e.g., triangles or trapezoids) then each membership function can be parameterized by a few variables and the membership optimization problem can be reduced to a parameter optimization problem. The parameter optimization problem can then be formulated as a nonlinear filtering problem. In this paper we solve the nonlinear filtering problem using H_∞ state estimation theory. However, the membership functions that result from this approach are not (in general) sum normal. …

Developing A Design Space Model Using A Multidisciplinary Design Optimization Schema In A Product Lifecycle Management System To Capture Knowledge For Reuse, Nathaniel Luke Fife

Theses and Dissertations

Parametric strategies for design automation and optimization can have a big impact on engineering design. When parametric tasks and optimization frameworks and methods are combined, theses strategies can be used to make up what is known as a multidisciplinary design optimization (MDO) schema. Knowledge of a design space can be modeled by using a MDO schema to represent the design process. However, current MDO frameworks used to create this schema lack the scope to capture enterprise wide knowledge for reuse and collaboration. Concurrent with the development of MDO, many companies are moving toward increased use of product lifecycle management (PLM). …

Developing New Multidimensional Knapsack Heuristics Based On Empirical Analysis Of Legacy Heuristics, Yong Kun Cho

Theses and Dissertations

The multidimensional knapsack problem (MKP) has been used to model a variety of practical optimization and decision-making applications. Due to its combinatorial nature, heuristics are often employed to quickly find good solutions to MKPs. While there have been a variety of heuristics proposed for the MKP, and a plethora of empirical studies comparing the performance of these heuristics, little has been done to garner a deeper understanding of heuristic performance as a function of problem structure. This dissertation presents a research methodology, empirical and theoretical results explicitly aimed at gaining a deeper understanding of heuristic procedural performance as a function …

Multi-Criteria Decision Analysis For The Optimal Management Of Nitrate Contamination Of Aquifers, Mohammad N. Almasri, Jagath J. Kaluarachchi

Civil and Environmental Engineering Faculty Publications

We present an integrated methodology for the optimal management of nitrate contamination of ground water combining environmental assessment and economic cost evaluation through multi-criteria decision analysis. The proposed methodology incorporates an integrated physical modeling framework accounting for on-ground nitrogen loading and losses, soil nitrogen dynamics, and fate and transport of nitrate in ground water to compute the sustainable on-ground nitrogen loading such that the maximum contaminant level is not violated. A number of protection alternatives to stipulate the predicted sustainable on-ground nitrogen loading are evaluated using the decision analysis that employs the importance order of criteria approach for ranking and …

Optimization Of Shape, Size, And Topology Design Variables In Trusses With A Genetic Algorithm, Kevin M. Gillman

Theses and Dissertations

Briggs' genetic algorithm was extended in the Gillman algorithm to include shape optimization of trusses. Other contributions include value representation, different member linking, alternate genes, automatic k-factor evaluation for buckling, and the option to prevent overlapping members. The purpose of these contributions was to make optimization using a genetic algorithm more accessible to design engineers. The Gillman algorithm was demonstrated in two original examples as well as an example from a published work. The Gillman algorithm was effective in finding lighter designs.

Optimization Of An Unstructured Finite Element Mesh For Tide And Storm Surge Modeling Applications In The Western North Atlantic Ocean, Satoshi Kojima

Electronic Theses and Dissertations

Recently, a highly resolved, finite element mesh was developed for the purpose of performing hydrodynamic calculations in the Western North Atlantic Tidal (WNAT) model domain. The WNAT model domain consists of the Gulf of Mexico, the Caribbean Sea, and the entire portion of the North Atlantic Ocean found west of the 60° W meridian. This high resolution mesh (333K) employs 332,582 computational nodes and 647,018 triangular elements to provide approximately 1.0 to 25 km node spacing. In the previous work, the 333K mesh was applied in a Localized Truncation Error Analysis (LTEA) to produce nodal density requirements for the WNAT …

Optimal Operating Strategy For Wells With Downhole Water Sink Completions To Control Water Production And Improve Performance, Ozan Arslan

LSU Doctoral Dissertations

Downhole water sink (DWS) technology is an alternative to conventional limited-entry completions to control water production in wells with bottom water drive. DWS wells comprise two completions: the bottom completion produces water and keeps the top completion open to oil inflow. The system performance depends on careful manipulation of the top and bottom rates to maximize oil productivity and produce oil-free water from the bottom completion. Conventional nodal analysis cannot provide a solution for DWS wells because the critical rates for water coning change with water drainage rate. A reservoir simulator is used to model two-phase flow to the dual …

A Methodology For Minimizing The Oscillations In Supply Chains Using System Dynamics And Genetic Algorithms, Ramamoorthy C.V.V. Lakkoju

Electronic Theses and Dissertations

Supply Chain Management (SCM) is a critically significant strategy that enterprises depend on to meet challenges that they face because of highly competitive and dynamic business environments of today. Supply chain management involves the entire network of processes from procurement of raw materials/services/technologies to manufacturing or servicing intermediate products/services to converting them into final products or services and then distributing and retailing them till they reach final customers. A supply chain network by nature is a large and complex, engineering and management system. Oscillations occurring in a supply chain because of internal and/or external influences and measures to be taken …

Multiobjective Optimization Of Seismic Structures, Franklin Y. Cheng, Dan Li, Jeffrey Ger

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper presents a constrained Mult objective optimization method in the form of a robust, practical, problem-independent formulation based on genetic algorithm combined with game theory and investigates the effect of Mult objective optimization on structural design. the study includes objectives, constraints, and design variables as well as their effect on structural design and behavior. the algorithm comprises - Mult objective fitness function, niche method, and Pareto set filter. a 10-story setback building is used to illustrate the evaluation of three choices: steel frame, reinforced concrete frame, composite steel and reinforced concrete frame. Evaluation is based on economics as well …

Optimización Para El Normado, Planeamiento, Diseño Y Manejo Del Agua Subterránea, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

Los modelos de Simulación/optimización (S/O) junta modelos de simulación y optimización para calcular estrategias óptimas para el manejo del agua subterránea ante problemas de optimización propuestos. Una estrategia es un conjunto de caudales de extracción e inyección de agua subterráneas distribuidas espacial y temporalmente. Los modelos S/O están llegando a ser más comúnmente usados para el desarrollo de normas, planeamiento, diseño del sistema y manejo. Por ejemplo, los encargados del manejo y planificación del agua algunas veces deben decidir como controlar el uso del agua subterránea para originar un futuro favorable y evitar serios problemas. Los modelos S/O pueden ayudar …

The Benefit Of Using Simulation To Improve The Implementation Of Lean Manufacturing Case Study: Quick Changeovers To Allow Level Loading Of The Assembly Line, Jack J. Mcclellan

Theses and Dissertations

In today's competitive manufacturing environment, companies are constantly looking for ways to improve. Because of this, many companies are striving to become "lean" by implementing lean manufacturing, which is a difficult process. To aid in the implementation of lean manufacturing, simulation was used to reduce the trial-and-error period of lean manufacturing and find to optimum approach to implement the lean manufacturing principle. In this research, a case study of implementing level loading of the production schedule for BullFrog International, L.C. will be examined. To make it possible to implement level loading, the thermo-former machine at the beginning of the operations …

Optimization Of Cell Density And Dilution Rate In Pichia Pastoris Continuous Fermentations For Production Of Recombinant Proteins, Wenhui Zhang, Chih-Ping Liu, Mehmet Inan, Michael M. Meagher

Papers in Biomolecular Engineering

This paper provides an approach for optimizing the cell density (X_c) and dilution rate (D) in a chemostat for a Pichia pastoris continuous fermentation for the extracellular production of a recombinant protein, interferon τ (INF-τ). The objective was to maximize the volumetric productivity (Q, mg INF-τ I^-1 h^-1), which was accomplished using response surface methodology (RSM) to model the response of Q as a function of X_c and D within the ranges 150 ≤ X_c ≤ 450 g cells (wet weight) l^-1 and 0.1 μm ≤ D …

Cost-Driven Optimization Of Fault Coverage In Combined Built-In Self-Test/Automated Test Equipment Testing, Shanrui Zhang, Minsu Choi, Nohpill Park, Fabrizio Lombardi

Electrical and Computer Engineering Faculty Research & Creative Works

As the design and fabrication complexities for the instrumentation-on-silicon systems intensify, optimization of combined Built-In Self-Test (BIST) and Automated Test Equipment (ATE) testing becomes more desirable to meet the required fault-coverage while maintaining acceptable cost overhead. The cost associated with combined BIST/ATE testing of such systems mainly consists of the following; (1) the cost induced by the BIST area overhead and (2) the cost induced by the overall testing time. In general, BIST has faster testing speed than ATE, while it can provide only limited fault-coverage and driving higher fault-coverage from BIST means additional area cost overhead. On the other …

Gradient-Based Non-Linear Microstructure Design, Brent L. Adams, M. Lyon

Faculty Publications

The support of this research by the Army Research Office is gratefully acknowledged. M. Lyon is supported by a National Science Foundation Graduate Research Fellowship. Fourier analysis is implemented on the orientation distribution of a polycrystalline microstructure. The linearity and convexity of the Fourier space, with respect to orientation, allows one to consider all possible distributions by considering all linear combinations of single-grain orientations. The limits of the Fourier space are therefore defined by the solutions to a set of linear programming problems. A unique approach to the linear programming, similar to the Krylov subspace methods for obtaining solutions to …

Data Smoothing And Interpolation Using Eighth-Order Algebraic Splines, Daniel J. Simon

Electrical and Computer Engineering Faculty Publications

A new type of algebraic spline is used to derive a filter for smoothing or interpolating discrete data points. The spline is dependent on control parameters that specify the relative importance of data fitting and the derivatives of the spline. A general spline of arbitrary order is first formulated using matrix equations. We then focus on eighth-order splines because of the continuity of their first three derivatives (desirable for motor and robotics applications). The spline's matrix equations are rewritten to give a recursive filter that can be implemented in real time for lengthy data sequences. The filter is lowpass with …

A Half D1 Mpeg-4 Encoder On The Bsp-15 Dsp, Lulin Chen, Zhihai He, Chang Wen Chen, Michael A. Isnardi

Electrical Engineering and Computer Science Faculty Publications

In this paper, we present the work on implementation of a half-Dl interlaced MPEG-4 encoder with Equator Technology DSP chip, BSP-15. The BSP-15 DSP consists mainly of a VLIW core, Co-processors, and media I/O interfaces. The encoder utilizes several BSP-15 functional blocks in parallel. In general, the VLIW performs pixel processing that is computationally intensive. The VLx coprocessor completes variable length coding. Further parallelism is obtained by pre-loading data cache and doubling data buffers. Given the DSP processing power and real time requirements, a complexity control scheme is implemented. A frame-level quantization scheme with quality and rate control is employed. …

A Simple And Global Optimization Algorithm For Engineering Problems: Differential Evolution Algorithm, Dervi̇ş Karaboğa, Selçuk Ökdem

Turkish Journal of Electrical Engineering and Computer Sciences

Differential Evolution (DE) algorithm is a new heuristic approach mainly having three advantages; finding the true global minimum regardless of the initial parameter values, fast convergence, and using few control parameters. DE algorithm is a population based algorithm like genetic algorithms using similar operators; crossover, mutation and selection. In this work, we have compared the performance of DE algorithm to that of some other well known versions of genetic algorithms: PGA, Grefensstette, Eshelman. In simulation studies, De Jong's test functions have been used. From the simulation results, it was observed that the convergence speed of DE is significantly better than …

Design Optimization Module For Hierarchical Research And Learning Environment, Oktay Baysal, Mehti Koklu, Ahmed K. Noor

Mechanical & Aerospace Engineering Faculty Publications

The present paper describes a learning module on design optimization courses within a hierarchical research and learning network (HRLN). In this environment a knowledge organization can be created as a hierarchical learning network to link diverse inter- and trans- disciplinary teams from a consortium of universities, industry, government agencies and the providers of learning technologies. It is an approach that builds on computer-based training, intelligent tutoring systems, interactive learning, collaborative-distributed learning, and learning networks. The present design optimization module has been developed and described herein, as a demonstrator of a learning module in this environment. This module allows for the …

New External Neuro-Controller For Series Capacitive Reactance Compensator In A Power Network, Jung-Wook Park, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

The controllable capacitive reactance can be used as the input variable for the external controller of a series capacitive reactance compensator (SCRC) to improve the damping of low-frequency oscillations of the rotor angle and active power in a power system. Conventional linear PI controllers are tuned for best performance at one specific operating point of the nonlinear power system. At other operating point its performance degrades. Nonlinear optimal neuro-controllers are able to overcome this degradation. In this paper, the dual heuristic dynamic programming (DHP) optimization algorithm is applied to design an external nonlinear optimal neuro-controller for the SCRC. Simulation studies …

Optimization Of A Skewed Logistic Distribution With Respect To The Kolmogorov-Smirnov Test, James Charles Finney

LSU Doctoral Dissertations

The four-parameter kappa distribution (Hosking 1994) was analyzed with respect to the various possible shapes of the probability density function. The general form for the cumulative distribution function when both h and k are non-zero is: F(x) = { 1 - h [ 1 - k ( x - ξ ) / α ]^1/k }^1/h. The parameters h and k work together to define the function's shape, ξ affects location, and α is the scale parameter. A method of selecting parameters to minimize the Kolmogorov-Smirnov test statistic, D, was developed. The technique was first described for the …

Multi-Objective Conjunctive Use Optimization, H. C. Fayad, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

This paper presents a simulation/optimization model based on artificial neural networks and genetic algorithms for solving multi-objective conjunctive water use problems. The model simulates and optimizes water flows in a hydraulically connected reservoir-stream-aquifer system. It is a powerful tool to help water managers and authorities in developing conjunctive water management strategies and evaluating tradeoffs between conflicting goals.

Optimization Modeling For Groundwater And Conjunctive Use Water Policy Development, Richard C. Peralta, R. Shulstad

Civil and Environmental Engineering Faculty Publications

Planners must sometimes decide how to restrict or reduce groundwater use to prevent unacceptable future problems. Often there are several alternatives (policies). Comparing policies can involve formulating a sustained groundwater yield optimization problem and computing an optimal groundwater pumping strategy for each. This is easy via the SOMOS simulation/optimization (S/O) model. Subsequent analysis can include: flow simulation to predict transient water level response to pumping; and economic evaluation to estimate costs and returns. Two examples predict the best consequences of potential physical and legal management policies for alluvial and valley basin fill aquifers hydraulically linked to surface waters. Results show …

Incorporating Functionally Graded Materials And Precipitation Hardening Into Microstructure Sensitive Design, Mark Edward Lyon

Theses and Dissertations

The methods of MSD are applied to the design of functionally graded materials. Analysis models are presented to allow the design of compliant derailleur for a case study and constraints are placed on the design. Several methods are presented for relating elements of the microstructure to the properties of the material, including Taylor yield theory, Hill elastic bounds, and precipitation hardening.

Applying n-point statistics to the MSD framework is also discussed. Some results are presented for the information content of the 2-point correlation statistics that follow from the methods used to integrate functionally graded materials into MSD.

For the compliant …

Optimization Of Municipal Solid Waste Management In Port Said, Mohamed Fathy Abd El-Rahman Mohamed Badran

Archived Theses and Dissertations

This thesis is done at the American University in Cairo, and titled "Optimization of Municipal Solid Waste Management in Port Said". This thesis is presented by Mohamed Fathy Abd El-Rahman Mohamed Badran, under the supervision of Dr. Salah El-Haggar. Optimization of solid waste management systems was not applied to any Egyptian govemorate using any operational research methodologies. A new concept is arising in the collection activity of municipal solid waste management which is the use of collection stations. This concept was not used in Egypt. In this work, a proposed model for the municipal solid waste management system in Port …