• Title/Summary/Keyword: Mathematical Optimization

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Performance Analysis and Design Optimization of Multi-Rate Spring Brake System (Multi-Rate 스프링 제동장치의 성능분석 및 최적설계)

  • Jung, Eui-Man;Won, Jun-Ho;Choi, Joo-Ho;Shim, In-Seob
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.18 no.4
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    • pp.67-72
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    • 2010
  • In this study, performance analysis and design optimization is carried out for a multi-rate spring brake system, which is used in a cable ride to stop the arriving passengers in safe and comfortable manner. Mathematical model for the spring is developed toward the objective of minimizing the impact at the arrival while satisfying the constraint of limited distance at the stop. Matlab code is utilized to examine parameters affecting the performance of the brake system. The results are validated by a commercial software RecurDyn. Kriging meta model is used to reduce the computational cost of the analysis. Optimization is conducted by RecurDyn, from which the design parameters are determined that minimizes the impact at the stop.

A Study on the Masses Reduction for the Structural Safety Using Optimal Design Method (최적 설계법을 이용한 구조물 안전을 위한 질량 감소 연구)

  • 신귀수;이기형;정인성
    • Journal of the Korean Society of Safety
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    • v.13 no.1
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    • pp.40-46
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    • 1998
  • This paper is presented that theoretical optimization design method in order to consider mass reduction for the structural safety In this paper, it described methods for reducing vibration in structural safety by the determination of the optimum sizes and locations of tunning masses through formal mathematical optimization techniques. The optimization procedure which employs the tunning masses and corresponding locations is developed. Design variables are systematically changed to achieve low values of shear without a large mass penalty. Three optimization methods ire developed and tested. The first is based on minimizing the modal shaping parameter which indirectly reduce the modal shear amplitudes corresponding to each harmonic of airload. The second method reduces these amplitudes directly and the third method reduces the shear as a function of time during a revolution of the blade. The first method works well for reducing the shear for one mode responding to a single harmonic of the airload but has been found in some bases to be ineffective for more than one mode.

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A Comparative Study of the Design Software Systems from the View Point of Optimization (최적설계 관점에서의 설계 소프트웨어 성능 비교에 관한 연구)

  • Hong, Eul-Pyo;Park, Cheol-Min;Park, Gyeong-Jin
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.1
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    • pp.83-94
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    • 2002
  • Analysis technology is widely accepted and quite popular these days. Incorporation of the analysis result into design process is a key factor for the success of the analysis area. A few design software products have been commercialized. Generally, they are trying to make an interface between various design methods and analysis software. Optimization is a representative design method. The products are investigated and compared for the aspects of user convenience and algorithm performance. A few popular products are selected. Graphic user interface (GU) is compared for the function and efficiency. The performances of the optimization algorithms are tested by mathematical and engineering examples. The results are discussed.

Research on theoretical optimization and experimental verification of minimum resistance hull form based on Rankine source method

  • Zhang, Bao-Ji;Zhang, Zhu-Xin
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.7 no.5
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    • pp.785-794
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    • 2015
  • To obtain low resistance and high efficiency energy-saving ship, minimum total resistance hull form design method is studied based on potential flow theory of wave-making resistance and considering the effects of tail viscous separation. With the sum of wave resistance and viscous resistance as objective functions and the parameters of B-Spline function as design variables, mathematical models are built using Nonlinear Programming Method (NLP) ensuring the basic limit of displacement and considering rear viscous separation. We develop ship lines optimization procedures with intellectual property rights. Series60 is used as parent ship in optimization design to obtain improved ship (Series60-1) theoretically. Then drag tests for the improved ship (Series60-1) is made to get the actual minimum total resistance hull form.

Optimization of Tyrosinase Production using Neurospora crassa (Neurospora crassa를 이용한 Tyrosinase 생산의 최적화)

  • 채희정;유영제
    • Microbiology and Biotechnology Letters
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    • v.19 no.3
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    • pp.281-289
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    • 1991
  • Neurospora crassa (KCTC 6079) produces tyrosinase (EC 1.14.18.1) during sexual differentiation under derepressed conditions in the presence of inducers such as amino acid analogues, antimetabolites or protein synthesis inhibitors. The selection of inducer concentration and induction time as well as inducer type are critical for the optimization of the enzyme production. The best inducer was found to be cycloheximide. Since cycloheximide was toxic to the cells, an optimal inducer concentration and an optimal induction time were determined to maximize the enzyme production from batch cultures. Mathematical models for the cell growth and the enzyme production were proposed and used for process optimization. By optimizing the induction conditions, maximum tyrosinase productivity was increased significantly.

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Parameter Optimal Choice of Claw Pole Alternator based on Iron Loss Model

  • Bao, Xiaohua;Wei, Qiong;Wu, Feng;Li, Jiaqing
    • Journal of international Conference on Electrical Machines and Systems
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    • v.2 no.3
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    • pp.260-268
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    • 2013
  • Based on classical Berotti discrete iron loss calculation model, the iron loss analysis mathematical model of alternator was proposed in this paper. Considering characteristics of high speed and changing frequency of the alternator, Maxwell 3-D model was built to analyze iron loss corresponding to each running speed in alternator. Based on iron loss model of alternator at rated speed, the rotor claw pole size was made an optimization design. The optimization results showed that alternator's output performance had been improved. A new idea was explored in size optimization design of claw pole alternator.

An Comparative Study of Metaheuristic Algorithms for the Optimum Design of Structures (구조물 최적설계를 위한 메타휴리스틱 알고리즘의 비교 연구)

  • RYU, Yeon-Sun;CHO, Hyun-Man
    • Journal of Fisheries and Marine Sciences Education
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    • v.29 no.2
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    • pp.544-551
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    • 2017
  • Metaheuristic algorithms are efficient techniques for a class of mathematical optimization problems without having to deeply adapt to the inherent nature of each problem. They are very useful for structural design optimization in which the cost of gradient computation can be very expensive. Among them, the characteristics of simulated annealing and genetic algorithms are briefly discussed. In Metropolis genetic algorithm, favorable features of Metropolis criterion in simulated annealing are incorporated in the reproduction operations of simple genetic algorithm. Numerical examples of structural design optimization are presented. The example structures are truss, breakwater and steel box girder bridge. From the theoretical evaluation and numerical experience, performance and applicability of metaheuristic algorithms for structural design optimization are discussed.

Optimal Design of Transformer Cores Using DEAS (DEAS를 이용한 변압기 코아의 최적설계)

  • Kim, Jong-Wook;Cha, Sang-Yun;Kim, Jae-Kwan
    • Proceedings of the KIEE Conference
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    • 2005.07b
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    • pp.917-920
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    • 2005
  • This paper introduces an optimal design technique for a 250-watt isolation transformer using a recently developed optimization method, dynamic encoding algorithm for searches(DRAS). Although the optimal design technique for transformers dates back to 1970s and local optimization is often undertaken using FEM nowadays, literature concerning global optimization of transformer cores is rarely found against its importance. In this paper, a small isolation transformer is used as a model to be optimized with application of DEAS to corresponding mathematical description. The optimization result confirms that DEAS can be successfully employed to design transformer cores for various design specifications only by changing cost functions.

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Optimum Sensitivity of Objective Function using Equality Constraint (등제한조건을 이용한 목적함수에 대한 최적민감도)

  • Yi S.I.;Shin J.K.;Park G.J.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.10a
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    • pp.464-469
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    • 2005
  • Optimum sensitivity analysis (OSA) is the process to find the sensitivity of optimum solution with respect to the parameter in the optimization problem. The prevalent OSA methods calculate the optimum sensitivity as a post-processing. In this research, a simple technique is proposed to obtain optimum sensitivity as a result of the original optimization problem, provided that the optimum sensitivity of objective function is required. The parameters are considered as additional design variables in the original optimization problem. And then, it is endowed with equality constraints to penalize the additional variables. When the optimization problem is solved, the optimum sensitivity of objective function is simultaneously obtained as Lagrange multiplier. Several mathematical and engineering examples are solved to show the applicability and efficiency of the method compared to other OSA ones.

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Analysis and optimal design of fiber-reinforced composite structures: sail against the wind

  • Nascimbene, R.
    • Wind and Structures
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    • v.16 no.6
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    • pp.541-560
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    • 2013
  • The aim of the paper is to use optimization and advanced numerical computation of a sail fiber-reinforced composite model to increase the performance of a yacht under wind action. Designing a composite-shell system against the wind is a very complex problem, which only in the last two decades has been approached by advanced modeling, optimization and computer fluid dynamics (CFDs) based methods. A sail is a tensile structure hoisted on the rig of a yacht, inflated by wind pressure. Our objective is the multiple criteria optimization of a sail, the engine of a yacht, in order to obtain the maximum thrust force for a given load distribution. We will compute the best possible yarn thickness orientation and distribution in order to minimize the total fiber volume with some displacement constraints and in order to leave the most uniform stress distribution over the whole structure. In this paper our attention will be focused on computer simulation, modeling and optimization of a sail-shape mathematical model in different regatta and wind conditions, with the purpose of improving maneuverability and speed made good.