• 제목/요약/키워드: optimal of convergence

검색결과 1,529건 처리시간 0.029초

Optimal Current Control Method of BLDC Motor Utilizing Maximum Torque Point

  • Park, Chang-Seok;Jang, Jung-Hoon;Jung, Tae-Uk
    • 한국산업융합학회 논문집
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    • 제20권3호
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    • pp.213-220
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    • 2017
  • This paper proposes an optimal current control method for improving efficiency of Brushless Direct Current (BLDC) motor. The proposed optimal current control method is based on the maximum torque point analysis of Finite Element Analysis (FEA). The proposed method can increase the effective voltage at the maximum torque point of BLDC motor and increase the output torque per unit current to increase the efficiency. In order to verify the proposed optimal current control method, have developed the prototype of a 50 [W] class motor drive and experimented by 20 [W] motor using the dynamometer set. This was verified.

STUDY OF OPTIMAL EIGHTH ORDER WEIGHTED-NEWTON METHODS IN BANACH SPACES

  • Argyros, Ioannis K.;Kumar, Deepak;Sharma, Janak Raj
    • 대한수학회논문집
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    • 제33권2호
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    • pp.677-693
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    • 2018
  • In this work, we generalize a family of optimal eighth order weighted-Newton methods to Banach spaces and study its local convergence to approximate a locally-unique solution of a system of nonlinear equations. The convergence in this study is shown under hypotheses only on the first derivative. Our analysis avoids the usual Taylor expansions requiring higher order derivatives but uses generalized Lipschitz-type conditions only on the first derivative. Moreover, our new approach provides computable radius of convergence as well as error bounds on the distances involved and estimates on the uniqueness of the solution based on some functions appearing in these generalized conditions. Such estimates are not provided in the approaches using Taylor expansions of higher order derivatives which may not exist or may be very expensive or impossible to compute. The convergence order is computed using computational order of convergence or approximate computational order of convergence which do not require usage of higher derivatives. This technique can be applied to any iterative method using Taylor expansions involving high order derivatives. The study of the local convergence based on Lipschitz constants is important because it provides the degree of difficulty for choosing initial points. In this sense the applicability of the method is expanded. Finally, numerical examples are provided to verify the theoretical results and to show the convergence behavior.

Optimal Rates of Convergence in Tensor Sobolev Space Regression

  • Koo, Ja-Yong
    • Journal of the Korean Statistical Society
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    • 제21권2호
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    • pp.153-166
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    • 1992
  • Consider an unknown regression function f of the response Y on a d-dimensional measurement variable X. It is assumed that f belongs to a tensor Sobolev space. Let T denote a differential operator. Let $\hat{T}_n$ denote an estimator of T(f) based on a random sample of size n from the distribution of (X, Y), and let $\Vert \hat{T}_n - T(f) \Vert_2$ be the usual $L_2$ norm of the restriction of $\hat{T}_n - T(f)$ to a subset of $R^d$. Under appropriate regularity conditions, the optimal rate of convergence for $\Vert \hat{T}_n - T(f) \Vert_2$ is discussed.

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유전알고리즘을 이용하여 최적화된 방제 자원 배치안의 분포도 분석 (Distribution Analysis of Optimal Equipment Assignment Using a Genetic Algorithm)

  • 김혜진;김용혁
    • 한국융합학회논문지
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    • 제11권4호
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    • pp.11-16
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    • 2020
  • 해양 오염사고를 대비한 계획으로, 최적화된 배치안들을 수집하여 분석하는 연구가 필수적이지만, 해양 오염사고 대응을 위한 최적을 배치안을 다양화하고 분석한 연구는 아직 선행되지 않았다. 이러한 필요성에 따라, 우리는 방제자원 배치 최적화를 위한 유전알고리즘을 고안하고 이를 통해 최적의 방제 자원 배치안을 10,000 개 도출하였다. k-평균 알고리즘으로 군집화한 결과, 예상 최대 유출지역인 여수, 대산, 울산에 대하여 두 개의 군집으로 확연히 구분되었다. 우리는 이러한 군집을 새몬 맵핑을 통해 이차원으로 사영하여 배치안의 분포도를 분석하였고, 군집에 포함되는 배치안들이 그렇지 않은 배치안보다 시뮬레이션의 결과가 우수함을 확인했다. 향후, 본 연구를 기반으로 성능이 우수한 근사모델을 구현하는 것이 가능할 것으로 보인다.

금속 그레이팅의 높이변화에 따른 최적치수 설계 및 안정성 해석 (Optimal Dimension Design and Stability Analysis of Non-slip Steel Grating)

  • 손인수
    • 한국산업융합학회 논문집
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    • 제25권3호
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    • pp.357-363
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    • 2022
  • In this study, in order to develop an non-slip metal grating, the stability of the grating according to the span of the grating and the gap and height of the bearing bar was evaluated. The optimal shape design of the grating was performed using the results of determining the stability of the grating. The purpose of this study is to determine the stability according to the spacing and height of the bearing bar by applying the design pressure at the design stage to develop the anti-skid grating, and to design the optimal shape for cost reduction. In the optimal design, the target variable was set as the mass, and the optimal design of the grating was performed based on about 20%. Regardless of the height of the bearing bar of the grating, the stress and deformation of the span and the grating showed a proportional tendency to each other, and it was found that the stress decreased as the height of the bearing bar increased. Based on the structural analysis results, an optimal design was performed using mass as the objective variable, and the existing 2mm thickness was changed to 1.6mm, reducing the mass by about 19%. The stress increased by about 4.4% compared to the maximum stress of the existing grating, but the minimum safety factor was 3.1, indicating that the optimally designed grating was stable.

헬리컬 기어의 최적 설계 프로그램 개발 및 3차원 모델링 (Development of the Optimal Design Program and the 3-D Modeling for the Helical Gear)

  • 곽재섭;정성원
    • 한국산업융합학회 논문집
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    • 제3권2호
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    • pp.107-114
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    • 2000
  • Recently the studies on the vibration and the noise of a helical gear transmission have been focused on the many researchers. The manufacturing error and the deformation of the tooth profile, which generates the vibration and the noise of the gear transmission, are main factors. The major purpose of this study is to develop an optimal design program for reducing the vibration and the noise of the helical gear. To obtain the these results, we restrain the helical gear from the deformation of the tooth profile and increase the contact ratio within the optimal design program. Furthermore we made the three-dimensional solid modeling of the helical gear from the AutoCAD and the Pro/Engineer. This model will be available to generate the finite element model and the NC code.

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차량의 도착모형을 이용한 독립교차로 신호최적화알고리즘 개발 (Development of a Signal Optimization Algorithm at Isolated Intersections Using Vehicle Arrival Models)

  • 우용한
    • 한국산업융합학회 논문집
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    • 제4권1호
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    • pp.41-49
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    • 2001
  • This study developed signal optimization algorithm by analyzing vehicle arrival patterns. The major principle of signal optimization is dissipate all queueing vehicle in 1cycle and assign delay time uniformly for all approaches. For this, this study used optimal green time and surplus green time. Optimal green time calculated by estimated traffic volume from vehicle arrival model. Surplus green time defined as the gap of optimal green time and queue dissipated time. And alternative cycle has minimum surplus green time was selected as the optimal cycle. Finally, total delay and average delay per vehicle can be calculated by using queueing theory.

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냉각수 가열장치의 안정화를 위한 유로 최적 설계 (Optimal Design of Flow Path to Improve Stability on Coolant Heater)

  • 한대성;배규현;윤현진
    • 반도체디스플레이기술학회지
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    • 제20권4호
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    • pp.134-140
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    • 2021
  • This study investigates the flow efficiency and temperature based on flow path shape. Five models are designed to the no flow path, one flow path, two flow path, three flow path, add inlet flow path and add interior space gradient. Results show that two flow model(add inlet flow path and add interior space gradient), It was confirmed that model(add inlet flow path) is the optimal shape for coolant heat transfer, and model(add interior space gradient) is the optimal shape for coolant flow, demonstrates optimal design among the five models. The results of this study can be utilized to efficiently control the coolant flow through various types of flow paths.

진화 시스템을 위한 유전자 알고리즘 프로세서의 구현 (Implementation of an Adaptive Genetic Algorithm Processor for Evolvable Hardware)

  • 정석우;김현식;김동순;정덕진
    • 대한전기학회논문지:시스템및제어부문D
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    • 제53권4호
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    • pp.265-276
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    • 2004
  • Genetic Algorithm(GA), that is shown stable performance to find an optimal solution, has been used as a method of solving large-scaled optimization problems with complex constraints in various applications. Since it takes so much time to execute a long computation process for iterative evolution and adaptation. In this paper, a hardware-based adaptive GA was proposed to reduce the serious computation time of the evolutionary process and to improve the accuracy of convergence to optimal solution. The proposed GA, based on steady-state model among continuos generation model, performs an adaptive mutation process with consideration of the evolution flow and the population diversity. The drawback of the GA, premature convergence, was solved by the proposed adaptation. The Performance improvement of convergence accuracy for some kinds of problem and condition reached to 5-100% with equivalent convergence speed to high-speed algorithm. The proposed adaptive GAP(Genetic Algorithm Processor) was implemented on FPGA device Xilinx XCV2000E of EHW board for face recognition.

An Improved Element Removal Method for Evolutionary Structural Optimization

  • Han, Seog-Young
    • Journal of Mechanical Science and Technology
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    • 제14권9호
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    • pp.913-919
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    • 2000
  • The purpose of this study was to develop a new element removal method for ESO (Evolutionary Structural Optimization), which is one of the topology optimization methods. ESO starts with the maximum allowable design space and the optimal topology emerges by a process of removal of lowly stressed elements. The element removal ratio of ESO is fixed throughout topology optimization at 1 or 2%. BESO (bidirectional ESO) starts with either the least number of elements connecting the loads to the supports, or an initial design domain that fits within the maximum allowable domain, and the optimal topology evolves by adding or subtracting elements. But the convergence rate of BESO is also very slow. In this paper, a new element removal method for ESO was developed for improvement of the convergence rate. Then it was applied to the same problems as those in papers published previously. From the results, it was verified that the convergence rate was significantly improved compared with ESO as well as BESO.

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