• Title/Summary/Keyword: Optimum Strategy

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System-Level Maintenance Strategy for Steel Bridges based on Life-Cycle Analysis (생애주기분석을 통한 강교량 시스템수준의 유지관리 전략)

  • Park, Kyung Hoon;Lee, Sang Yoon;Kim, Jung Ho;Cho, Hyo Nam;Kong, Jung Sik
    • Journal of Korean Society of Steel Construction
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    • v.20 no.2
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    • pp.259-268
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    • 2008
  • This paper proposes a method to establish an optical lifetime maintenance strategy for deteriorating bridges in consideration of life-cycle performance and cost. A program is developed based on the proposed method, which can generate optimum maintenance scenarios not only at the individual member level but also at the system level of the bridge. By applying the developed program is studied through the comparative analysis of maintenance strategies generated at each level. According to the results of comparison between maintenance strategies of the member-level analysis and system-level analysis. It is expected that the establishment of a maintenance strategy through the bridge system-level analysis considering target, members reflects practical and reasonable results.

Enhancing yield and nutritive value of forage through corn soybean intercropping strategy at seventeen different places in Republic of Korea

  • Song, Yowook;Kim, Dong Woo;Kim, Jeongtae;Fiaz, Muhamad;Kwon, Chan Ho
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.37 no.2
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    • pp.101-107
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    • 2017
  • Corn is basal forage for livestock species in Republic of Korea but it lacks protein and needs nitrogenous fertilizer. This study was designed with main objective to achieve optimum growth, yield & nutritive value of forage for livestock through implementing corn-soybean intercropping strategy at 17 different places under Korean condition. Two treatments; corn as monocrop (control treatment) and corn-soybean intercrop were compared under Randomized Block Design from $28^{th}$ May to $8^{th}$ October, 2015. Each treatment had three replicates in each block, whereas seventeen different places were considered as blocks. Data were analyzed through SAS-9.1.3 software. Difference between two treatment means was tested through T-test. Findings depicted that intercropping pattern could not influence (P>0.05) corn plant & ear height, corn lodged stalk No. and corn stalks number. However, corn-soybean intercropping enhanced (P<0.05) forage productivity in terms of total fresh yield ($16.4{\pm}0.7^b$ vs. $19.9{\pm}0.7^atons\;ha^{-1}$), total dry matter yield ($5.38{\pm}0.25^b$ vs. $6.41{\pm}0.31^atons\;ha^{-1}$) and total digestible nutrients yield ($3.94{\pm}0.17^b$ vs. $4.59{\pm}0.21^atons\;ha^{-1}$). Dry matter percentage in corn stalks and corn ears was not different (P>0.05) between two treatments. It was concluded that corn-soybean intercropping strategy was promising technique in enhancing forage productivity though positive symbiotic relation between two crops.

A hybrid identification method on butterfly optimization and differential evolution algorithm

  • Zhou, Hongyuan;Zhang, Guangcai;Wang, Xiaojuan;Ni, Pinghe;Zhang, Jian
    • Smart Structures and Systems
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    • v.26 no.3
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    • pp.345-360
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    • 2020
  • Modern swarm intelligence heuristic search methods are widely applied in the field of structural health monitoring due to their advantages of excellent global search capacity, loose requirement of initial guess and ease of computational implementation etc. To this end, a hybrid strategy is proposed based on butterfly optimization algorithm (BOA) and differential evolution (DE) with purpose of effective combination of their merits. In the proposed identification strategy, two improvements including mutation and crossover operations of DE, and dynamic adaptive operators are introduced into original BOA to reduce the risk to be trapped in local optimum and increase global search capability. The performance of the proposed algorithm, hybrid butterfly optimization and differential evolution algorithm (HBODEA) is evaluated by two numerical examples of a simply supported beam and a 37-bar truss structure, as well as an experimental test of 8-story shear-type steel frame structure in the laboratory. Compared with BOA and DE, the numerical and experimental results show that the proposed HBODEA is more robust to detect the reduction of stiffness with limited sensors and contaminated measurements. In addition, the effect of search space, two dynamic operators, population size on identification accuracy and efficiency of the proposed identification strategy are further investigated.

Permanent Preservation and Use of Historical Archives : Preservation Issues Digitization of Historical Collection (역사기록물(Archives)의 항구적인 보존화 이용 : 보존전략과 디지털정보화)

  • Lee, Sang-min
    • The Korean Journal of Archival Studies
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    • no.1
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    • pp.23-76
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    • 2000
  • In this paper, I examined what have been researched and determined about preservation strategy and selection of preservation media in the western archival community. Archivists have primarily been concerned with 'preservation' and 'use' of archival materials worth of being preserved permanently. In the new information era, preservation and use of archival materials were faced with new challenge. Life expectancy of paper records was shortened due to acidification and brittleness of the modem papers. Also emergence of information technology affects the traditional way of preservation and use of archival materials. User expectations are becoming so high technology-oriented and so complicated as to make archivists act like information managers using computer technology rather than traditional archival handicraft. Preservation strategy plays an important role in archival management as well as information management. For a cost-effective management of archives and archival institutions, preservation strategy is a must. The preservation strategy encompasses all aspects of archival preservation process and practices, from selection of archives, appraisal, inventorying, arrangement, description, conservation, microfilming or digitization, archival buildings, and access service. Those archival functions should be considered in their relations to each other to ensure proper preservation of archival materials. In the integrated preservation strategy, 'preservation' and 'use' should be combined and fulfilled without sacrificing the other. Preservation strategy planning is essential to determine the policies of archives to preserve their holdings safe and provide people with a maximum access in most effective ways. Preservation microfilming is to ensure permanent preservation of information held in important archival materials. To do this, a detailed standardization has been developed to guarantee the permanence of microfilm as well as its product quality. Silver gelatin film can last up to 500 years in the optimum storage environment and the most viable option for permanent preservation media. ISO and ANIS developed such standards for the quality of microfilms and microfilming technology. Preservation microfilming guidelines was also developed to ensure effective archival management and picture quality of microfilms. It is essential to assess the need of preservation microfilming. Limit in resources always put a restraint on preservation management. Appraisal (and selection) of what to be preserved was the most important part of preservation microfilming. In addition, microfilms with standard quality can be scanned to produce quality digital images for instant use through internet. As information technology develops, archivists began to utilize information technology to make preservation easier and more economical, and to promote use of archival materials through computer communication network. Digitization was introduced to provide easy and universal access to unique archives, and its large capacity of preserving archival data seems very promising. However, digitization, i.e., transferring images of records to electronic codes, still, needs to be standardized. Digitized data are electronic records, and st present electronic records are very unstable and not to be preserved permanently. Digital media including optical disks materials have not been proved as reliable media for permanent preservation. Due to their chemical coating and physical character using light, they are not stable and can be preserved at best 100 years in the optimum storage environment. Most CD-R can last only 20 years. Furthermore, obsolescence of hardware and software makes hard to reproduce digital images made from earlier versions. Even if when reformatting is possible, the cost of refreshing or upgrading of digital images is very expensive and the very process has to be done at least every five to ten years. No standard for this obsolescence of hardware and software has come into being yet. In short, digital permanence is not a fact, but remains to be uncertain possibility. Archivists must consider in their preservation planning both risk of introducing new technology and promising possibility of new technology at the same time. In planning digitization of historical materials, archivists should incorporate planning for maintaining digitized images and reformatting them in the coming generations of new applications. Without the comprehensive planning, future use of the expensive digital images will become unavailable. And that is a loss of information, and a final failure of both 'preservation' and 'use' of archival materials. As peter Adelstein said, it is wise to be conservative when considerations of conservations are involved.

The Optimum Design of Truss Dome Structures by Evolution Strategy (진화전략을 이용한 트러스 돔 구조물의 최적설계)

  • Han, Sang-Eul;Kim, Man-Jung;Lee, Jae-Young;Ryu, Ji-Su
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2009.04a
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    • pp.396-399
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    • 2009
  • 본 논문의 연구 목적은 생물의 진화 현상을 모방한 진화전략 알고리즘을 이용하여 돔형 트러스 구조물을 최적화 설계하는 것이다. 최적화 방법으로 부재 단면적의 최적화 값을 찾음으로써 최적 목적값 또는 최소 구조물 중량을 산출하는데 목적이 있다. 진화전략 알고리즘은 1960년대 중반, 실수기반 매개변수의 최적화로부터 소개되어 1970년대 많은 발전을 하였다. 진화전략은 컴퓨터 시스템 최적화 알고리즘 연구분야에서 많이 활용되며, 더불어 사용되는 유전자 알고리즘과는 다른 몇 개의 연산자를 가지고 있다. 본 논문에서는 진화전략에서 사용되는 연산자를 소개하고 연산자간의 논리 흐름과 수치예제로써 최적설계의 적합성을 확인해볼 수 있다.

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A Method for RBF-based Approximate Optimization of Expensive Black Box Functions (고비용 블랙박스 함수의 RBF기반 근사 최적화 기법)

  • Park, Sangkun
    • Korean Journal of Computational Design and Engineering
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    • v.21 no.4
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    • pp.443-452
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    • 2016
  • This paper proposes a method for expensive black box optimization using radial basis functions (RBFs). The proposed algorithm is a computational strategy that uses a RBF model approximating the expensive black box function to predict an optimum. First, a RBF-based approximation technique is introduced and a sampling plan for estimation of the black box function is described. Then the proposed algorithm is explained, which presents the pseudo-codes for implementation and the detailed description of each step performed in the optimization process. In addition, numerical experiments will be given to analyze the performance of the proposed algorithm, by investigating computation accuracy, number of function evaluations, and convergence history. Finally, geometric distance problem as application example will be also presented for showing the algorithm applicability to different engineering problems.

Implementing an Analysis System for Housing Business Based on Seoul Apartment Price Data (주택 사업 분석 시스템 구축 : 서울지역 아파트 가격 데이터를 중심으로)

  • 김태훈;이희석;김재윤;전진오;이은식
    • The Journal of Information Technology and Database
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    • v.6 no.2
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    • pp.115-130
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    • 1999
  • The price structure of housing market varies depending upon market price policy rather than low or high price policy because of IMF. The object of this study is to develop an analysis system for analyzing housing market and its demand. The analysis system consists of four major categories: macro index analysis, market decision analysis, housing market analysis, and consumer analysis. We model each category by using a variety of techniques such as generalized linear model, categorical analysis, bubble analysis, drill-down analysis, price sensitivity meter analysis, optimum price index analysis, profit index measurement analysis, correspondence analysis, conjoint analysis, and multidimensional scaling analysis. Seoul apartment data is analyzed to demonstrate the practical usefulness of the system.

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An Expert System for Optimal Network Reconfiguration in Distribution Systems (배전계통의 최적 회로재구성을 위한 전문가 시스템)

  • Yoon, Yong-Han;Kim, Jae-Chul;Jang, Jeong-Tae
    • Proceedings of the KIEE Conference
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    • 1991.11a
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    • pp.71-74
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    • 1991
  • This paper is described an expert system which performs the network reconfiguration in order to operate distribution systems optimally using heuristic rules. The proposed network reconfiguration is able to not only eliminate abnormal states such as overload of transformers/lines and low voltage violation, but also achieve minimum power loss and optimum load balancing under normal states. In order to apply the network reconfiguration efficiently, an expert system is adopted a best-first tree searching strategy on the basis of heuristics, and is implemented in AI language Turbo PROLOG. Several examples are used to illustrate concepts described above.

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Optimal Environmental and Economic Operation using Evolutionary Computation and Neural Networks (진화연산과 신경망이론을 이용한 전력계통의 최적환경 및 경제운용)

  • Rhee, Sang-Bong;Kim, Kyu-Ho;You, Seok-Ku
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.48 no.12
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    • pp.1498-1506
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    • 1999
  • In this paper, a hybridization of Evolutionary Strategy (ES) and a Two-Phase Neural Network(TPNN) is applied to the optimal environmental and economic operation. As the evolutionary computation, ES is to search for the global optimum based on natural selection and genetics but it shows a defect of reducing the convergence rate in the latter part of search, and often does not search the exact solution. Also, neural network theory as a local search technique can be used to search a more exact solution. But it also has the defect that a solution frequently sticks to the local region. So, new algorithm is presented as hybrid methods by combining merits of two methods. The hybrid algorithm has been tested on Emission Constrained Economic Dispatch (ECED) problem and Weighted Emission Economic Dispatch (WEED) problem for optimal environmental and economic operation. The result indicated that the hybrid approach can outperform the other computational efficiency and accuracy.

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A Research on Process of Estimation about Frequency and Loss of Risk by distribution of Probability (확률분포에 의한 리스크 빈도수와 손실규모 추정 프로세스 연구)

  • Lee, Young-Jai;Lee, Seong-Il
    • Journal of Information Technology Applications and Management
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    • v.15 no.2
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    • pp.67-82
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    • 2008
  • Risk that breed large size disaster is happening variously for cause at social. natural a management. Incidence and damage scale are trend that increase rapidly than past. In these circumstance, to keep operational continuity of organization, area, society, risk management action that establish systematic counter measure estimating and analyze occurrence possibility and expectation damage of risk is essential indispensable issue and the best countermeasure. Risk management action does by main purpose establish optimum disaster reduction countermeasure. To deduce various countermeasure, process that estimate and analyze occurrence possibility and expectation damage of risk is essential indispensable issue. Therefore, this paper studies process design that can presume risk occurrence frequency and damage scale through distribution of probability.

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