• Title/Summary/Keyword: Local Solution

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Fuzzy Model Identification Using VmGA

  • Park, Jong-Il;Oh, Jae-Heung;Joo, Young-Hoon
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.2 no.1
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    • pp.53-58
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    • 2002
  • In the construction of successful fuzzy models for nonlinear systems, the identification of an optimal fuzzy model system is an important and difficult problem. Traditionally, sGA(simple genetic algorithm) has been used to identify structures and parameters of fuzzy model because it has the ability to search the optimal solution somewhat globally. But SGA optimization process may be the reason of the premature local convergence when the appearance of the superior individual at the population evolution. Therefore, in this paper we propose a new method that can yield a successful fuzzy model using VmGA(virus messy genetic algorithms). The proposed method not only can be the countermeasure of premature convergence through the local information changed in population, but also has more effective and adaptive structure with respect to using changeable length string. In order to demonstrate the superiority and generality of the fuzzy modeling using VmGA, we finally applied the proposed fuzzy modeling methodof a complex nonlinear system.

Analysis on Required Capacity of Energy Storage System to Mitigate Wind Power Fluctuation (풍력발전기의 출력 안정화를 위한 에너지 저장장치 용량 산정 사례연구)

  • Kang, Min Hyeok;Chae, Sang Heon;Ahn, Jin Hong;Kim, Eel-Hwan
    • Journal of the Korean Solar Energy Society
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    • v.37 no.6
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    • pp.59-68
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    • 2017
  • In accordance with the policy of local government, the large scale of wind farms have been installed in Jeju power system. However, The intermittent characteristics of wind power output may cause grid voltage and frequency variation, especially in weak power system. One of the solution to solve this problem is installation of Energy storage system (ESS). In this case, the ESS will regulate the active power generated from wind farm to mitigate fluctuation. Actually, the local government of Jeju island constructed ESS connected to Hangwon wind turbine in 2016. From this point, this paper analyzes requirement capacity of ESS to mitigate wind power fluctuation based on measured data from Hangwon wind turbine and ESS. The simulation results will be carried out by Matlab program.

The JFNK method for the PWR's transient simulation considering neutronics, thermal hydraulics and mechanics

  • He, Qingming;Zhang, Yijun;Liu, Zhouyu;Cao, Liangzhi;Wu, Hongchun
    • Nuclear Engineering and Technology
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    • v.52 no.2
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    • pp.258-270
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    • 2020
  • A new task of using the Jacobian-Free-Newton-Krylov (JFNK) method for the PWR core transient simulations involving neutronics, thermal hydraulics and mechanics is conducted. For the transient scenario of PWR, normally the Picard iteration of the coupled coarse-mesh nodal equations and parallel channel TH equations is performed to get the transient solution. In order to solve the coupled equations faster and more stable, the Newton Krylov (NK) method based on the explicit matrix was studied. However, the NK method is hard to be extended to the cases with more physics phenomenon coupled, thus the JFNK based iteration scheme is developed for the nodal method and parallel-channel TH method. The local gap conductance is sensitive to the gap width and will influence the temperature distribution in the fuel rod significantly. To further consider the local gap conductance during the transient scenario, a 1D mechanics model is coupled into the JFNK scheme to account for the fuel thermal expansion effect. To improve the efficiency, the physics-based precondition and scaling technique are developed for the JFNK iteration. Numerical tests show good convergence behavior of the iterations and demonstrate the influence of the fuel thermal expansion effect during the rod ejection problems.

Poverty Alleviation Efforts through MDG's and Economic Resources in Indonesia

  • LAURENS, Samson;PUTRA, Aditya Halim Perdana Kusuma
    • The Journal of Asian Finance, Economics and Business
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    • v.7 no.9
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    • pp.755-767
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    • 2020
  • The objective of this study is to examine and provide guidelines for regional governments, communities, and the private sector in planning and implementing poverty-reduction activities that are more effective, efficient, and targeted. Besides, this research's specific aims are: 1) increasing the rate of regional economic growth through optimization of potential sources of local income, 2) increasing per-capita income, and 3) reducing poverty, unemployment, and social-economic inequality of the community. The study was conducted in North Morowali District, Central Sulawesi Province, Indonesia, in 2018-2019. The research approach used quantitative and qualitative descriptive analysis. Data sources include sources from the Focus Group Discussion (FGD) and Regional Statistics. The results of this study are based on the Millennium Development Goals (MDG's) indicators that there are four priority scales in poverty reduction, namely, Health and Infrastructure (Priority I), Education (Priority II), Food stability (Priority III), and Population and Employment (Priority IV). Therefore, as a solution to poverty alleviation strategies, the cost approach through regional economic optimization and local income sources and community empowerment factors are essential. Apart from that, the involvement between elements (government, organizations, society, universities, and institutions) is expected to continue as an effort to realize poverty reduction can be optimally overcome.

Development of Atmospheric Environmental Sensitivity Index by Socio-Statistical Survey (사회통계조사에 의한 대기환경 체감지수의 개발)

  • Kim Hyun-Goo;Lee Yung-Seop;Koo Cha-Mun;Ko Yu-Na
    • Journal of Korean Society for Atmospheric Environment
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    • v.22 no.4
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    • pp.421-430
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    • 2006
  • This paper explores a new methodology of socio-statistical survey to classify environmental perception characteristics and to quantify atmospheric environmental sensitivity of neighboring people around a large industrial complex. In order to compensate intrinsic inclination against environmental problems, Atmospheric Environmental Sensitivity Index (AESI) is proposed as the weighted-summation of four representative questions asking the current status of the local air quality, which are chosen by the factor analysis of questionnaire. Atmospheric environmental perception is tried to be classified into interest/indifference characteristics and rational/emotional perception on environmental issues, positive/negative opinion on the solution of environmental problems. According to the chi-square cross-correlation and two-way layout analyses, it was clearly shown that environmental perception is categorized into two major groups, i.e., the positive-rational group having lower AESI and the negative-emotional group having higher AESI which means more seriously senses the status of local air quality.

LOCAL PERMUTATION POLYNOMIALS OVER FINITE FIELDS

  • Lee, Jung-Bok;Ko, Hyoung-June
    • Communications of the Korean Mathematical Society
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    • v.9 no.3
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    • pp.539-545
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    • 1994
  • Let $q = p^r$, where p is a prime. A polynomial $f(x) \in GF(q)[x]$ is called a permutation polynomial (PP) over GF(q) if the numbers f(a) where $a \in GF(Q)$ are a permutation of the a's. In other words, the equation f(x) = a has a unique solution in GF(q) for each $a \in GF(q)$. More generally, $f(x_1, \cdots, x_n)$ is a PP in n variables if $f(x_1,\cdots,x_n) = \alpha$ has exactly $q^{n-1}$ solutions in $GF(q)^n$ for each $\alpha \in GF(q)$. Mullen ([3], [4], [5]) has studied the concepts of local permutation polynomials (LPP's) over finite fields. A polynomial $f(x_i, x_2, \cdots, x_n) \in GF(q)[x_i, \codts,x_n]$ is called a LPP if for each i = 1,\cdots, n, f(a_i,\cdots,x_n]$ is a PP in $x_i$ for all $a_j \in GF(q), j \neq 1$.Mullen ([3],[4]) found a set of necessary and three variables over GF(q) in order that f be a LPP. As examples, there are 12 LPP's over GF(3) in two indeterminates ; $f(x_1, x_2) = a_{10}x_1 + a_{10}x_2 + a_{00}$ where $a_{10} = 1$ or 2, $a_{01} = 1$ or x, $a_{00} = 0,1$, or 2. There are 24 LPP's over GF(3) of three indeterminates ; $F(x_1, x_2, x_3) = ax_1 + bx_2 +cx_3 +d$ where a,b and c = 1 or 2, d = 0,1, or 2.

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A Study on the Constructional Characteristics of Jeju-HyangGyo (제주향교의 조영적 특성에 관한 연구)

  • Ji, Tae-Seung;Park, Chung-Keun;Park, Chul-Min
    • Journal of the Korean Institute of Rural Architecture
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    • v.10 no.3
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    • pp.59-66
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    • 2008
  • This study was performed to ascertain how HyangGyos based on national ideology were built in Jeju Island and what their detailed styles are. In Jeju-HyangGyo, unique architectural characteristics are shown as they have been built in an island independent from the mainland. Also up-down system was well reflected in detailed architectural styles. The main temple of Jeju-HyangGyo was built in the type of one-Chulmok(a subsidiary material of Gongpo and a piece of wood to support the eaves) of which ancon supports a purline from the center of a pillar and two-Ikgong(a piece of wood engraved to put on an ancon), but in the case of the lecture hall, its Gongpo(a piece of wood to support the eaves) was inferior in quality. In the case of Jeju abutments were used in main temples and fire walls were mostly used. In particular, their abutments are difficult to be observed in HyangGyo in the mainland. It is presumed that the abutment and the fire wall used in Jeju Island might be the best solution to protect structures from rain and moisture. To sum up, local characteristics and traditional rules were thoroughly reflected in Jeju-HyangGyos built in Jeju Island from the aspect of arrangement and detailed style. In conclusion, it is significant that architectural styles, not to mention the other aspects of Jeju culture, were suitably adapted to Jeju Island.

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Optimal Design for Steam-turbine Rotor-bearing System Using Combined Genetic Algorithm (조합 유전 알고리듬을 이용한 증기 터빈 회전체-베어링 시스템의 최적설계)

  • Kim, Young-Chan;Choi, Seong-Pil;Yang, Bo-Suk
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.12 no.5
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    • pp.380-388
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    • 2002
  • This paper describes the optimum design for low-pressure steam turbine rotor of 1,000 MW nuclear power plant by using a combined genetic algorithm, which uses both a genetic algorithm and a local concentrate search algorithm (e.g. simplex method). This algorithm is not only faster than the standard genetic algorithm but also supplies a more accurate solution. In addition, this algorithm can find the global and local optimum solutions. The objective is to minimize the resonance response (Q factor) and total weight of the shaft, and to separate the critical speeds as far from the operating speed as possible. These factors play very important roles in designing a rotor-bearing system under the dynamic behavior constraint. In the present work, the shaft diameter, the bearing length, and clearance are used as the design variables. The results show that the proposed algorithm can improve the Q factor and reduce the weight of the shaft and the 1st critical speed.

Development of Network Level Management System of Road Facilities Based on the Asset Management Concept (자산관리개념을 접목한 네트워크 방식의 도로시설물 유지관리시스템 개발)

  • Ji, Seung Gu;Seo, Jong Won
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.15 no.4
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    • pp.146-154
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    • 2011
  • Recently, the paradigm of social infrastructure investment has been changed from new construction to maintenance and management. As a consequence, the management and maintenance system of existing highway facilities needed an innovation involving the concept of asset management. This paper discusses the new facility management system suitable to local highway agencies. The new system incorporates asset management concept so that it can analyze the network level facility management solution and it can also improve the budget efficiency for local government. This paper also presents systematic method to integrate various facilities for management system.

Wind effects on a large cantilevered flat roof: loading characteristics and strategy of reduction

  • Fu, J.Y.;Li, Q.S.;Xie, Z.N.
    • Wind and Structures
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    • v.8 no.5
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    • pp.357-372
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    • 2005
  • Mean and extreme pressure distributions on a large cantilevered flat roof model are measured in a boundary layer wind tunnel. The largest peak suction values are observed from pressure taps beneath conical "delta-wing type" corner vortices that occur for oblique winds, then the characteristics and causes of the local peak suctions are discussed in detail. Power spectra of fluctuating wind pressures measured from some typical taps located at the roof edges under different wind directions are presented, and coherence functions of fluctuating pressures are also obtained. Based on these results, it is verified that the peak suctions are highly correlated with the conical vortices. Furthermore, according to the characteristics of wind loads on the roof, an aerodynamic solution to minimize the peak suctions by venting the leading edges and the corners of the roof is recommended. The experimental results show that the suggested strategy can effectively control the generation of the conical vortices and make a reduction of 50% in mean pressures and 25% in extreme local pressures at wind sensitive locations on the roof.