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Collection of Technical Papers - 10th AIAA/ISSMO multidisciplinary Analysis and optimization Conference

作者： Choi, Seongim Alonso, Juan J. Kroo, Ilan M. Wintzer, Mathias Stanford University Stanford CA 94305 United States Desktop Aeronautics Inc. Palo Alto CA 94301 United States

ISBN: (纸本)1563477165

The practical use of high-fidelity multidisciplinary optimization techniques in low-boom supersonic business jet designs has been limited because of the high computational cost associated with CFD-based evaluations of both the performance and the loudness of the ground boom of the aircraft. This is particularly true of designs that involve the sonic boom loudness as either a cost function or a constraint because gradient-free optimization techniques may become necessary, leading to even larger numbers of function evaluations. If, in addition, the objective of the design method is to account for the performance of the aircraft throughout its mission (T/O and landing, climb, acceleration, etc.) while including important multi-disciplinary trade-offs between the relevant disciplines (performance, boom, structures, stability and control, propulsion, etc.) the situation only worsens. In order to overcome these limitations, we propose a hierarchical multi-fidelity design approach where high-fidelity models are only used where and when they are needed to correct the shortcomings of the low-fidelity models. Our design approach consists of two basic components: a multi-disciplinary aircraft synthesis tool (PASS) that uses highly-tuned low-fidelity models of all of the relevant disciplines and computes the complete mission profile of the aircraft, and a hierarchical, multi-fidelity environment for the creation of response surfaces for aerodynamic performance and sonic boom loudness (BOOM-UA) that attempts to achieve the accuracy of an Euler-based design strategy. This procedure is used to create three design alternatives for a Mach 1.6, 6-8 passenger supersonic business jet configuration with a range of 4,500 nmi and with a T/O field length that is shorter than 6,000 ft. Optimized results are obtained with much lower computational cost than the direct, high-fidelity design alternative. The validation of these design results using the high-fidelity model show very good agreeme

关键词： Jet aircraft

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Bone Remodeling as a Hybrid Cellular Automaton optimization Process

Bone Remodeling as a Hybrid Cellular Automaton Optimization ...

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作者： Andrés Tovar University of Notre Dame

学位级别：博士

Biological structures are continually adapting to changes in their physical environ- ment. In bones, for example, it has been widely accepted that mineral tissue is resorbed in regions exposed to low mechanical stimulus, whereas new bone is deposited where the stimulus is high. This process of functional adaptation is thought to enable bone to perform its mechanical functions with a minimum of mass. Many theoretical models for bone remodeling use this concept as part of the strategy to simulate bone structural adap- tation. These models imply the existence of an equilibrium state where the bone struc- ture is adapted to the environment and no net remodeling is required. The first practical computational models were developed under the assumption of isotropy of the trabecu- lar structure in the continuum level. Despite the similarities in density distribution with in-vivo bone, no convergent solution was possible to obtain. Recent models have been developed to consider the anisotropic nature of the trabecular bone in the continuum level making use of optimization principles; however, despite of some mechanical aspects re- flected by these idealized microstructures, they just represent a mathematical abstraction of the trabecular architecture. The objective of this investigation is to develop an algorithm that incorporates tissue- level mechanisms of bone functional adaptation compatible with both phenomenologi- cal and optimization approaches. This technique makes use of the cellular automaton paradigm and concepts of structural optimization. The algorithm also incorporates the finite element method to perform structural analysis over a design domain that represents the bone structure. This design domain is composed of a lattice of sensor cells or cellular automata. These cells activate local processes of formation and resorption with changes in their relative variable mass. Parameters of the proposed algorithm include mechanotrans- duction of the mechanical stimulus

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Nonlinear multi-Criteria optimization for the Integrated Design and Control of Bioprocesses

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IFAC Proceedings Volumes 2004年第3期37卷 571-576页

作者： Oscar H. Sendin Carmen G. Moles Antonio A. Alonso Julio R. Banga Process Engineering Group Instituto Investigaciones Marinas (CSIC) Eduardo Cabello 6 36208 Vigo SPAIN

The simultaneous design and control of continuous bioprocesses is considered here as a multi-objective optimization problem subject to non-linear differential-algebraic constraints. This type of problem is very challenging to solve due to its non-convexity (multi-modality). We present two novel solution approaches based on extensions of an stochastic global optimization method. The robustness and efficiency of these approaches are illustrated with a wastewater treatment plant case study.

关键词： multiple-criterion optimisation global optimisation integrated plant control biotechnology waste treatment

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Efficient methods for reliability-based design optimization

Efficient methods for reliability-based design optimization

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作者： Zou, Tong Vanderbilt University

学位级别：Ph.D.

This dissertation develops efficient methods for reliability-based design optimization (RBDO). Accurate and efficient methods are developed for reliability analysis at both component and system levels. Efficient optimization approaches are developed to enable the accurate reliability methods to be adopted by RBDO. Two reliability analysis methods are developed. The first method combines analytical and simulation-based methods through adaptive response surfaces, and the second method performs Monte Carlo simulation based on the response surface of the failure indicator function. The developed methods are applied to solve an automotive door problem in terms of satisfying two quality issues. A general framework of the proposed method for reliability analysis of problems with a large number of random variables at both component and system level is constructed. A decoupling method for efficient RBDO approach is developed next, based on direct reliability analysis, as opposed to existing decoupling methods that depend on inverse first-order reliability analysis. Since the proposed approach does not depend on first-order reliability method for reliability analysis, it can take advantage of more accurate reliability analysis methods, leading to higher accuracy and actual feasibility of the RBDO solution. A decoupled RBDO method using efficient simulation-based techniques for reliability assessment is also presented. The use of simulation enables system-level reliability to be included in the decoupled RBDO formulation. The proposed decoupled RBDO methods are applied to a vehicle side impact problem. The satisfaction of the two automotive quality issues are probabilistically evaluated and treated as two objectives in the optimization formulation. A multi-objective RBDO method is developed to generate a series of solutions, under different scenarios, which can be utilized to facilitate decision-making. The proposed method is general and can be applied to solve a wide variety

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multiobjective genetic search for spanning tree problem

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11th International Conference on Neural Information Processing, ICONIP 2004

作者： Kumar, Rajeev Singh, P.K. Chakrabarti, P.P. Department of Computer Science and Engineering Indian Institute of Technology Kharagpur KharagpurWB721 302 India

ISBN: (纸本)3540239316

A major challenge to solving multiobjective optimization problems is to capture possibly all the (representative) equivalent and diverse solutions at convergence. In this paper, we attempt to solve the generic multi-objective spanning tree (MOST) problem using an evolutionary algorithm (EA). We consider, without loss of generality, edge-cost and tree-diameter as the two objectives, and use a multiobjective evolutionary algorithm (MOEA) that produces diverse solutions without needing a priori knowledge of the solution space. We test this approach for generating (near-) optimal spanning trees, and compare the solutions obtained from other conventional approaches. © Springer-Verlag Berlin Heidelberg 2004.

关键词： multiobjective optimization

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木薯乙醇—汽油混合燃料生命周期能源消耗多目标优化研究

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内燃机学报 2004年第4期22卷 351-356页

作者：胡志远浦耿强王成焘上海交通大学机械与动力工程学院上海200030

建立了木薯乙醇—汽油混合燃料生命周期能源消耗单目标和多目标优化模型。以生命周期总体能源消耗、化石燃料消耗和石油消耗为优化目标,对木薯乙醇—汽油混合燃料生命周期能源消耗进行了单目标及多目标优化,并进行了灵敏度分析。结果表... 详细信息

建立了木薯乙醇—汽油混合燃料生命周期能源消耗单目标和多目标优化模型。以生命周期总体能源消耗、化石燃料消耗和石油消耗为优化目标,对木薯乙醇—汽油混合燃料生命周期能源消耗进行了单目标及多目标优化,并进行了灵敏度分析。结果表明:多目标优化能使木薯乙醇—汽油混合燃料的生命周期总体能源、化石燃料和石油消耗同时降低,可以为木薯乙醇—汽油混合燃料的应用提供决策依据,具有重要的应用价值。

关键词：发动机生命周期能源多目标优化木薯乙醇汽油混合燃料

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Collection of Technical Papers - 45th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference;12th AIAA/ASME/AHS Adaptive Structures Conference;6th AIAA Non-Deterministic approaches Forum;5th AIAA Gossamer Spacecraft Forum - Volume 6

Collection of Technical Papers - 45th AIAA/ASME/ASCE/AHS/ASC...

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Collect. of Pap. - 45th AIAA/ASME/ASCE/AHS/ASC Struct., Struct. Dyn. and Mater. Conf.;12th AIAA/ASME/AHS Adapt. Struct. Conf.;6th AIAA Non-Deterministic approaches Forum;5th AIAA Gossamer Spacecraft Forum

The proceedings contain 70 papers from the Collection of Technical Papers - 45th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference;12th AIAA/ASME/AHS Adaptive Structures Conference;6th AIAA Non-Deterministic approaches Forum;5th AIAA Gossamer Spacecraft Forum - Volume 6. The topics discussed include: multi-objective reliability-based optimization;efficient reliability-based structural optimization through most probable failure point approximation;vibration isolator for large space telescopes;particle damping applications;automated identification of damping treatment characteristics;and a gradient-dependent constitutive model to simulate impact damage problem.

关键词： Oscillators (mechanical)

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Finite element analysis and genetic algorithm optimization design for the actuator placement on a large adaptive structure

Finite element analysis and genetic algorithm optimization d...

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作者： Sheng, Lizeng Virginia Polytechnic Institute and State University

学位级别：Ph.D.

The dissertation focuses on one of the major research needs in the area of adaptive/intelligent/smart structures, the development and application of finite element analysis and genetic algorithms for optimal design of large-scale adaptive structures. We first review some basic concepts in finite element method and genetic algorithms, along with the research on smart structures. Then we propose a solution methodology for solving a critical problem in the design of a next generation of large-scale adaptive structures---optimal placements of a large number of actuators to control thermal deformations. After briefly reviewing the three most frequently used general approaches to derive a finite element formulation, the dissertation presents techniques associated with general shell finite element analysis using flat triangular laminated composite elements. The element used here has three nodes and eighteen degrees of freedom and is obtained by combining a triangular membrane element and a triangular plate bending element. The element includes the coupling effect between membrane deformation and bending deformation. The membrane element is derived from the linear strain triangular element using Cook's transformation. The discrete Kirchhoff triangular (DKT) element is used as the plate bending element. For completeness, a complete derivation of the DKT is presented. Geometrically nonlinear finite element formulation is derived for the analysis of adaptive structures under the combined thermal and electrical loads. Next, we solve the optimization problems of placing a large number of piezoelectric actuators to control thermal distortions in a large mirror in the presence of four different thermal loads. We then extend this to a multi-objective optimization problem of determining only one set of piezoelectric actuator locations that can be used to control the deformation in the same mirror under the action of any one of the four thermal loads. A series of genetic algorithms,

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optimization of test /diagnosis /rework location(s) and characteristics in electronic systems assembly

Optimization of test /diagnosis /rework location(s) and char...

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作者： Shi, Zhen University of Maryland College Park

学位级别：Ph.D.

For electronic systems it is not uncommon for 60% or more of the recurring cost to be associated with testing. Performing tradeoffs associated with where in a process to test and what level of test, diagnosis and rework to perform are key to optimizing the cost and yield of an electronic system's assembly. In this dissertation, a methodology that uses a real-coded genetic algorithm has been developed to minimize the yielded cost of electronic products by optimizing the locations of test, diagnosis and rework operations and their characteristics. This dissertation presents a test, diagnosis, and rework analysis model for use in electronic systems assembly. The approach includes a model of functional test operations characterized by fault coverage, false positives, and defects introduced in test; in addition, rework and diagnosis operations (diagnostic test) have variable success rates and their own defect introduction mechanisms. The model accommodates multiple rework attempts on a product instance. For use in practical assembly processes, the model has been extended by defining a general form of the relationship between test cost and fault coverage. The model is applied within a framework for optimizing the location(s) and characteristics (fault coverage/test cost and rework attempts) of Test/Diagnosis/Rework (TDR) operations in a general assembly process. A new search algorithm called Waiting Sequence Search (WSS) is applied to traverse a general process flow to perform the cumulative calculation of a yielded cost objective function. Real-Coded Genetic Algorithms (RCGAs) are used to perform a multi-variable optimization that minimizes yielded cost. Several simple cases are analyzed for validation and general complex process flows are used to demonstrate the applicability of the algorithm. A real multichip module (MCM) manufacturing and assembly process is used to demonstrate that the optimization methodology developed in this dissertation can find test and rework s

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On the design and optimization of waveguides using evolutionary approaches

On the design and optimization of waveguides using evolution...

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Antennas and Propagation Society International Symposium

作者： Y.A. Hussein S.M. El-Ghazaly Stanford Linear Accelerator Center University of Stanford Menlo Park CA USA University of Tennessee Knoxville TN USA

This work presents a new and efficient CAD-oriented algorithm for the design and optimization of high frequency coupled coplanar waveguides (CCPW). The technique is based on genetic algorithms to obtain the global optimal solution of the problem. The proposed algorithm optimizes a multi-objective highly nonlinear problem having multiple local minima with one constraint. The new approach obtains the optimal structure dimensions that minimize the attenuation and at the same time is as close as possible to the circuit matching condition. After validation, the proposed technique is compared to a global search optimizer and then successfully applied to the design of practical monolithic implementations.

关键词： Design optimization Attenuation Impedance Genetic algorithms Algorithm design and analysis Coplanar waveguides Equations Coupling circuits optimization methods Linear accelerators

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