• Title, Summary, Keyword: Optimal Order Point

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SELF-DUAL CODES AND FIXED-POINT-FREE PERMUTATIONS OF ORDER 2

  • Kim, Hyun Jin
    • Bulletin of the Korean Mathematical Society
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    • v.51 no.4
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    • pp.1175-1186
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    • 2014
  • We construct new binary optimal self-dual codes of length 50. We develop a construction method for binary self-dual codes with a fixed-point-free automorphism of order 2. Using this method, we find new binary optimal self-dual codes of length 52. From these codes, we obtain Lee-optimal self-dual codes over the ring $\mathbb{F}_2+u\mathbb{F}_2$ of lengths 25 and 26.

Robust Optimal Design Method Using Two-Point Diagonal Quadratic Approximation and Statistical Constraints (이점 대각 이차 근사화 기법과 통계적 제한조건을 적용한 강건 최적설계 기법)

  • Kwon, Yong-Sam;Kim, Min-Soo;Kim, Jong-Rip;Choi, Dong-Hoon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.12
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    • pp.2483-2491
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    • 2002
  • This study presents an efficient method for robust optimal design. In order to avoid the excessive evaluations of the exact performance functions, two-point diagonal quadratic approximation method is employed for approximating them during optimization process. This approximation method is one of the two point approximation methods. Therefore, the second order sensitivity information of the approximated performance functions are calculated by an analytical method. As a result, this enables one to avoid the expensive evaluations of the exact $2^{nd}$ derivatives of the performance functions unlike the conventional robust optimal design methods based on the gradient information. Finally, in order to show the numerical performance of the proposed method, one mathematical problem and two mechanical design problems are solved and their results are compared with those of the conventional methods.

Optimal Current Control Method of BLDC Motor Utilizing Maximum Torque Point

  • Park, Chang-Seok;Jang, Jung-Hoon;Jung, Tae-Uk
    • Journal of the Korean Society of Industry Convergence
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    • v.20 no.3
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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.

ON A GENERAL CLASS OF OPTIMAL FOURTH-ORDER MULTIPLE-ROOT FINDERS

  • Kim, Young Ik
    • Journal of the Chungcheong Mathematical Society
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    • v.26 no.3
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    • pp.657-669
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    • 2013
  • A general class of two-point optimal fourth-order methods is proposed for locating multiple roots of a nonlinear equation. We investigate convergence analysis and computational properties for the family. Special and simple cases are considered for real-life applications. Numerical experiments strongly verify the convergence behavior and the developed theory.

Coupling Particles Swarm Optimization for Multimodal Electromagnetic Problems

  • Pham, Minh-Trien;Song, Min-Ho;Koh, Chang-Seop
    • Journal of Electrical Engineering and Technology
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    • v.5 no.3
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    • pp.423-430
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    • 2010
  • Particle swarm optimization (PSO) algorithm is designed to find a single global optimal point. However, the PSO needs to be modified in order to find multiple optimal points of a multimodal function. These modifications usually divide a swarm of particles into multiple subswarms; in turn, these subswarms try to find their own optimal point, resulting in multiple optimal points. In this work, we present a new PSO algorithm, called coupling PSO to find multiple optimal points of a multimodal function based on coupling particles. In the coupling PSO, each main particle may generate a new particle to form a couple, after which the couple searches its own optimal point using non-stop-moving PSO algorithm. We tested the suggested algorithm and other ones, such as clustering PSO and niche PSO, over three analytic functions. The coupling PSO algorithm was also applied to solve a significant benchmark problem, the TEAM workshop problem 22.

A Study on the Optimal Voltage for MPPT Obtained by only Surface's Temperature of Solar Cell (태양전지 온도 센싱만을 통한 태양광 발전시스템의 최적 운전전압에 관한 연구)

  • Minwon Park;In-Keun Yi
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.53 no.4
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    • pp.269-275
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    • 2004
  • Photovoltaic(PV) system has been studied and watched with keen interest due to a clean and renewable power source. But, the output power of PV system is not only unstable but uncontrollable, because the maximum power point tracking (MPPT) of PV system is still hard with the tracking failure under the sudden fluctuation of irradiance. Authors suggest that the optimal voltage for MPPT be obtained by only solar cell temperature. Having an eye on that the optimal voltage point of solar cell is in proportion to its panel temperature, with operating the power converter whose operating point keeps its input voltage to the optimal voltage imagined by the surface's temperature of PV panel, the maximum power point becomes tenderly possible to be tracked. In order to confirm the availability of the proposed control scheme. And both control methods are simulated not only on the various angle of sampling time of switching control, but also with the real field weather condition. As the results of that, the conversion efficiency between PV panel and converter of the proposed control scheme was much better than that of the power comparison MPPT control, and what is better, the output voltage of PV panel was extremely in stable when the optimal voltage for MPPT is obtained by only solar cell temperature.

A Study on the Maintenance Policy Considering the Failure Data of the EMU Braking System and the Cost Function (전동차 제동장치의 고장데이터와 비용함수를 고려한 유지보수 정책에 관한 연구)

  • Han, Jae-Hyun;Kim, Jong-Woon;Koo, Jeong-Seo
    • Journal of the Korean Society of Safety
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    • v.30 no.3
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    • pp.13-19
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    • 2015
  • Railway vehicle equipment goes back again to the state just before when failure by the repair. In repairable system, we are interested in the failure interval. As such, a statistical model of the point process, NHPP power law is often used for the reliability analysis of a repairable system. In order to derive a quantitative reliability value of repairable system, we analyze the failure data of the air brake system of the train line 7. The quantitative value is the failure intensity function that was modified, converted into a cost-rate function. Finally we studied the optimal number and optimal interval in which the costs to a minimum consumption point as cost-rate function. The minimum cost point was 194,613 (won/day) during the total life cycle of the braking system, then the optimal interval were 2,251days and the number of optimal preventive maintenance were 7 times. Additionally, we were compared to the cost of a currently fixed interval(4Y) and the optimum interval then the optimal interval is 3,853(won/day) consuming smaller. In addition, judging from the total life, "fixed interval" is smaller than 1,157 days as "optimal interval".

Optimal location of Batcher Plant using Modified Steiner point (수정된 Steiner Point를 이용한 Batcher Plant의 최적 위치 선정)

  • Ha, Kwon-Yeol;Lee, Sang-Joong
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.29 no.10
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    • pp.39-46
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    • 2015
  • REMICON(Ready Mixed Concrete), the most essential material of construction work, is produced from facility called "Batcher plant." In order to produce Remicon, Batcher Plant needs to be supplied with basic raw material such as ballast, sand, cement, admixture and water. In remicon industry, overland transport vehicles are used during the whole manufacturing process from producing to infilling at the construction site. Thus, the transportation cost sums up be to 20 percent of whole manufacturing cost and transport capacity and distance travelled have direct and major effect on manufacturing costs. This paper suggests a method to find optimal location of batcher plant using modified Steiner point, suggesting the most effective and flexible connection through among construction site, aggregate, cement and remicon producing plant. This paper also proposes reducing of transport cost at maximum 60% by calculation through optimized plant location. The modified Steiner point theory proposed in this paper also can be applied to optimal location of a $2^{ry}$ substation or MCC panel for minimizing of power loss, voltage drop, line distance and etc.

Second order integral sliding mode observer and controller for a nuclear reactor

  • Surjagade, Piyush V.;Shimjith, S.R.;Tiwari, A.P.
    • Nuclear Engineering and Technology
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    • v.52 no.3
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    • pp.552-559
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    • 2020
  • This paper presents an observer-based chattering free robust optimal control scheme to regulate the total power of a nuclear reactor. The non-linear model of nuclear reactor is linearized around a steady state operating point to obtain a linear model for which an optimal second order integral sliding mode controller is designed. A second order integral sliding mode observer is also designed to estimate the unmeasurable states. In order to avoid the chattering effect, the discontinuous input of both observer and controller are designed using the super-twisting algorithm. The proposed controller is realized by combining an optimal linear tracking controller with a second order integral sliding mode controller to ensure minimum control effort and robustness of the closed-loop system in the presence of uncertainties. The condition for the selection of gains of discontinuous control based on the super-twisting algorithm is derived using a strict Lyapunov function. Performance of the proposed observer based control scheme is demonstrated through non-linear simulation studies.

An Analytical Study on the Optimal Set-point of the Hybrid Plant (복합열원설비 운전온도 최적 설정에 관한 해석적 연구)

  • Jeon, Jong-Ug;Lee, Sun-Il;Lee, Tae-Won;Kim, Yong-Ki;Hong, Dae-Hie;Kim, Yong-Chan
    • Proceedings of the SAREK Conference
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    • pp.352-357
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    • 2007
  • The objective of this study is to find the optimal set-point of a hybrid Plant, which is combined by renewable energy plant of the GSHP(Ground Source Heat Pump) and the conventional plant(chiller, boiler). The work presented in this study was carried out by using the EnergyPlus(Version 2.0). In order to validate the simulation model, field data were measured from a building. The GSHP was used as a base plant and the conventional plant as the assistant plant. Various temperatures were controlled (zone summer set-point, zone winter set-point, chilled water temperature, hot water temperature) to find the optimal set-point temperature of the system. The influence of the various set-points were analyzed seasonally.

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