• Title/Summary/Keyword: Unconstrained optimization

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Optimum Design of Power Screw Efficiency by Fuzzy Simplex Search Algorithm (퍼지 simplex search 알고리듬을 이용한 동력 스크류 효율의 최적설계)

  • Hyun, Chang-Hun;Lee, Byeong-Ki
    • Journal of Industrial Technology
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    • v.22 no.A
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    • pp.19-28
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    • 2002
  • The Nelder-Mead simplex algorithm has been one of the most widely used methods for the nonlinear unconstrained optimization, since 1965. Recently, the new algorithm, (so-called the Fuzzy Simplex Algorithm), with fuzzy logic controllers for the expansion, reflection and contraction process of this algorithm has been proposed. In this paper, this new algorithm is developed. And, the formulation for the optimum design of the power screw's efficiency is made. And then, the developed fuzzy simplex algorithm as well as the original one is applied to this optimum design problem. The Fuzzy simplex algorithm results in a faster convergence in this problem, as reported in other study, too.

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On the optimization of the design variables of linear induction motor for 3-D conveyor system (입체 반송용 선형유도전동기의 설계 변수 최적화에 대하여)

  • Im, Dal-Ho;Kim, Gyu-Tak;Park, Seung-Chan
    • Proceedings of the KIEE Conference
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    • 1991.07a
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    • pp.139-142
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    • 1991
  • The design variables of SLIM used for 3-D conveyor system are optimized by nonlinear programing. Five design variables are selected as independent ones and object function is expressed as a combination of the weight and the normal force of the motor. Maximum flux density in the teeth, primary length and starting thrust are chosen as constraint functions. Goodness factor considering of conveying characteristic is also included in the constraints. In this paper sequential unconstrained minimization technique(SUMT) and variable metric method are used to solve the nonlinear problem.

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A Tool for Optimizing Simulated Discrete Variable Stochastic Systems: SIMICOM

  • Lee, Young-Hae;Azadivar, F.
    • Journal of Korean Institute of Industrial Engineers
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    • v.12 no.1
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    • pp.107-118
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    • 1986
  • A heuristic algorithm (SIMICOM) has been designed and tested for optimizing simulated stochastic systems whose performances are functions of several discrete decision variables. The approach adopted utilizes an integer complex method coupled with techniques of establishing confidence intervals for the system's responses. It can handle a general class of optimization problems that could be constrained or unconstrained. In constrained cases, the constraints could either be explicit analytical functions of decision variables or be expressed as other responses of the simulation model. In addition to obtain a reasonably accurate solution, the economic aspect of obtaining the solution has also been taken into consideration.

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Optimum Design Criteria based on Capacity of Synchronous Reluctance Motor Using a Coupled FEM & SUMT (유한요소법을 이용한 동기형 릴럭턴스 전동기의 용량에 따른 회전자 구조설계와 SUMT를 이용한 최적설계)

  • Kwon, Sun-Bum;Kim, Gi-Bok;Lee, Jung-Ho
    • Proceedings of the KIEE Conference
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    • 2004.10a
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    • pp.126-128
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    • 2004
  • This paper deals with an automatic optimum design based on capacity for a synchronous reluctance motor (SynRM). The focus of this paper is the design relative to the output power on the basis of rotor shape of a SynRM in each capacity. And optimization algorithm is used by means of sequential unconstrained minimization technique(SUMT). The coupled Finite Elements Analysis (FEA) & Preisach model have been used to evaluate nonlinear solutions. The proposed procedure allows to define the rotor geometric dimensions according to capacity starting from an existing motor or a preliminary design.

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Daily Streamfiow Model based on the Soil Water (유역 토양 수분 추적에 의한 유출 모형)

  • 김태일;여재경;박승기
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.33 no.4
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    • pp.61-72
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    • 1991
  • A lumped deterministic model(DAWAST model) was developed to predict the daily streamflow. Since the streamflow is dominantly determined by the soil water storage in the watershed, the model takes the soil water accounting procedures which are based on three linear reservoirs representing the surface, unsaturated, and saturated soil layers. The variation of soil water storage in the unsaturated zone is traced from the soil water balance on a daily basis. DAWAST model consists of 5 parameters for water balance and 3 parameters for routing. A optimization technique of unconstrained nonlinear Simplex method was applied for the determination of the optimal parameters for water balance. Model verification was carried out to the 7 hydrologic watersheds with areas of 5.89-7,126km$^2$ and the results were generally satisfactory. The daily streamflow can be arbitrarily simulated with the input data of daily rainfall and pan evaporation by the DAWAST model at the station where the observed streamflow data of short periods are available to calibrate the model parameters.

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A Constrained Receding Horizon Estimator with FIR Structures

  • Kim, Pyung-Soo;Lee, Young-Sam
    • Transactions on Control, Automation and Systems Engineering
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    • v.3 no.4
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    • pp.289-292
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    • 2001
  • This paper concerns with a receding horizon estimator (RHE) for discrete-time linear systems subject to constraints on the estimate. In solving the optimization for every horizons, the past all measurement data outside the horizon is discarded and thus the arrival cost is not considered. The RHE in the current work is a finite impulse response (FIR) structure which has some good inherent properties. The proposed RHE can be represented in the simple matrix form for the unconstrained case. Various numerical examples demonstrate how including constraints in the RHE can improve estimation performance. Especially, in the application to the unknown input estimation, it will be shown how the FIR structure in the RHE can improve the estimation speed.

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Dynamic behaviour of multi-stiffened plates

  • Bedair, Osama
    • Structural Engineering and Mechanics
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    • v.31 no.3
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    • pp.277-296
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    • 2009
  • The paper investigates the dynamic behaviour of stiffened panels. The coupled differential equations for eccentric stiffening configuration are first derived. Then a semi-analytical procedure for dynamic analysis of stiffened panels is presented. Unlike finite element or finite strip methods, where the plate is discretized into a set of elements or strips, the plate in this procedure is treated as a single element. The potential energy of the structure is first expressed in terms generalized functions that describe the longitudinal and transverse displacement profiles. The resulting non-linear strain energy functions are then transformed into unconstrained optimization problem in which mathematical programming techniques are employed to determine the magnitude of the lowest natural frequency and the associated mode shape for pre-selected plate/stiffener geometric parameters. The described procedure is verified with other numerical methods for several stiffened panels. Results are then presented showing the variation of the natural frequency with plate/stiffener geometric parameters for various stiffening configurations.

The Optimal Design of SAW Filters with Arbitrary Frequency Characteristics (임의의 주파수 특성을 갖는 표면음파 필터의 최적 설계)

  • Park, Seog-Hong;Son, Yeong-Chan;Yu, Sang-Dae
    • Journal of Sensor Science and Technology
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    • v.5 no.4
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    • pp.81-87
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    • 1996
  • This paper presents the optimal design method of SAW filters with arbitrary frequency characteristics. The design program using the unconstrained nonlinear optimization method and FFT algorithm is developed for optimal design of SAW filters with arbitrary frequency characteristics. As a design example, a SAW TV IF filter with asymmetric-amplitude and nonlinear-phase frequency characteristics is designed.

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Comparative Experiment of FMINS with Nelder-Mead and Dennis-Woods Method (Nelder-Mead, Dennis-Woods Method와 MATLAB의 FMINS의 비교실험)

  • Choe, Yeong-Il;Hyun, Chang-Hun
    • Journal of Industrial Technology
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    • v.19
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    • pp.361-368
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    • 1999
  • The Nelder-Mead simplex algorithm has become on of the most widely used methods for nonlinear unconstrained optimization, since 1965. Recently, this algorithm has been reevaluated and many papers on this algorithm are being published. The MATLAB computer software, highly renown in engineering, also provides the Nelder-Mead algorithm and the Denis-Woods modification with FMINS function. The authors made C++ code of these algorithms and compared with FMINS on the convergence behavior and the exactness of solutions. It shows that MATLAB's FMINS is inferior to author's C++ code. So, FMINS should be corrected for every user.

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Efficient Rate Control by Fast Adaptive Mode Selection

  • Ryu, Chul
    • The Journal of the Acoustical Society of Korea
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    • v.18 no.4E
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    • pp.43-50
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    • 1999
  • A fast converging coding algorithm that adaptively selects the modes of macroblocks is introduced. For a given frame, the optimal modes are selected based on the decision curves that minimize the overall distortion at a given bit rate. The method proposed in this paper is different from the conventional ones in that it does not manipulate the quantizer to meet the target bit rate but it satisfies the target bit rate by finding optimal modes of macroblocks which result consistent visual quality. Lagrange multiplier of the unconstrained cost function is controlled to trigger decision curves to generate appropriate modes to meet bit rate and the curve is obtained by utilizing simulated annealing optimization technique. The algorithm is implemented within H.261 video codec and simulation results demonstrate superior visual quality.

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