• Title/Summary/Keyword: 비용 함수

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The Heuristic based on the Ant Colony Optimization using by the Multi-Cost Function to Solve the Vehicle Routing and Scheduling Problem (차량 경로 스케줄링 문제 해결을 위한 멀티 비용 함수를 갖는 개미 군집 최적화 기법 기반의 휴리스틱)

  • Hong, Myung-Duk;Yu, Young-Hoon;Jo, Geun-Sik
    • Proceedings of the Korea Information Processing Society Conference
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    • 2010.04a
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    • pp.314-317
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    • 2010
  • 본 연구는 차량 경로 스케줄링 문제(VRSPTW, the Vehicle Routing and Scheduling Problem with Time Window)를 해결하기 위하여, 멀티 비용 함수(Multi Cost Function)를 갖는 개미 군집 최적화(Ant Colony Optimization)을 이용한 휴리스틱을 제안하였다. 멀티 비용 함수는 각 개미가 다음 고객 노드로 이동하기 위해 비용을 평가할 때 거리, 요구량, 각도, 시간제약에 대해 서로 다른 가중치를 반영하여 우수한 초기 경로를 구할 수 있도록 한다. 본 연구의 실험결과에서 제안된 휴리스틱이 Solomon I1 휴리스틱과 기회시간이 반영된 하이브리드 휴리스틱보다 효율적으로 최근사 해를 얻을 수 있음을 보였다.

Calculation of optimal design flood using cost-benefit analysis with uncertainty (불확실성이 고려된 비용-편익분석 기법을 도입한 최적설계홍수량 산정)

  • Kim, Sang Ug;Choi, Kwang Bae
    • Journal of Korea Water Resources Association
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    • v.55 no.6
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    • pp.405-419
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    • 2022
  • Flood frequency analysis commonly used to design the hydraulic structures to minimize flood damage includes uncertainty. Therefore, the most appropriate design flood within a uncertainty should be selected in the final stage of a hydraulic structure, but related studies were rarely carried out. The total expected cost function introduced into the flood frequency analysis is a new approach for determining the optimal design flood. This procedure has been used as UNCODE (UNcertainty COmpliant DEsign), but the application has not yet been introduced in South Korea. This study introduced the mathematical procedure of UNCODE and calculated the optimal design flood using the annual maximum inflow of hydroelectric dams located in the Bukhan River system and results were compared with that of the existing flood frequency. The parameter uncertainty was considered in the total expected cost function using the Gumbel and the GEV distribution, and the Metropolis-Hastings algorithm was used to sample the parameters. In this study, cost function and damage function were assumed to be a first-order linear function. It was found that the medians of the optimal design flood for 4 Hydroelectric dams, 2 probability distributions, and 2 return periods were calculated to be somewhat larger than the design flood by the existing flood frequency analysis. In the future, it is needed to develop the practical approximated procedure to UNCODE.

자동공정관리에서 최적의 관리모수 선정

  • 이재헌
    • Communications for Statistical Applications and Methods
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    • v.5 no.2
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    • pp.361-371
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    • 1998
  • 공정수정을 목적으로 하는 자동공정관리는 품질특성 치를 목표치에 가능한한 일치하도록 공정을 조정하고 관리한다. 본 논문에서는 자동공정관리에서 정의되는 비용함수를 최소화하는 관리모수를 선정하는 방법을 제시한다. 이를 위하여 Lee(1997)가 제안한 비용함수의 추정식을 사용하며, Kramer(1989)와 Box와 framer(1992)에 의해 연구된 방법과 비교한 결과 본 논문에서 제안된 방법이 계산하기 간편하면서도 충분히 좋은 정확성을 갖음을 알 수 있었다.

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Blind frequency offset estimation method in OFDM systems (OFDM에서 블라인드 주파수 옵셋 추정 방법)

  • Jeon, Hyoung-Goo
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.15 no.4
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    • pp.823-832
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    • 2011
  • In this paper, an efficient blind carrier frequency offset (CFO) estimation method in orthogonal frequency division multiplexing (OFDM) systems is proposed. In the proposed method, we obtain two time different received OFDM symbols by using both the cyclic prefix and oversampling technique, and a cost function is defined by using the two OFDM symbols. We show that the cost function can be approximately expressed as a cosine function. Using a property of the cosine function, a formular for estimating the CFO is derived. The estimator of the CFO requires three independent cost function values calculated at three different points of frequency offset. The proposed method is very efficient in computational complexity since no searching operation for the minimum cost value is required. The proposed method reduces 97% of the amount of FFT computation, compared with the ML method. Unlike the conventional methods such as the ML method and the MUSIC] method, the accuracy of the proposed method is independent of the searching resolution since the closed form solution exists. The computer simulation shows that the performance of the proposed method is superior to those of the MUSIC and the ML method.

다기간 사업의 비김분석

  • 김지수;김진욱
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 1992.04b
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    • pp.218-227
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    • 1992
  • 전통적인 비김분석이 기업의 이익계획이나 의사결정에 간단하면서도 유용한 방법이긴 하지만, 소득함수나 비용함수를 선형함수로 가정함으로써 현실성이 결여된 점과 기업에서 경제성평가의 대상이 되는 투자대안들이 다기간이거나 장기인 사업들이 대부분인데도 단기간의 분석으로 제한된 점이 이 분석의 유용성을 크게 떨어뜨리고 있다. 이 논문은 장기적인 사업에서 일반적인 비용이나 수익의 변동성을 고려하여 전통적인 비김분석을 다기간의 사업에도 적용할 수 있도록 한다.

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The Cost Structure of the Lines of Urban Railway (도시철도 노선의 비용구조 분석)

  • Kim, Soo Hyun;Jung, Hun Young
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.34 no.5
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    • pp.1559-1569
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    • 2014
  • The purpose of this study is to estimate the degree of cost inefficiency for the urban railway lines of a metropolitan city operated by public institutions in Korea and identify the causes of this inefficiency. To this end, we assume that the urban railway lines produce the output of train-km by putting three production factors of labor, electric power and maintenance and set the variable cost function model with the translog function to make a stochastic cost frontier analysis. Based on estimated result, we conclude that the cost savings for 6 years of all lines are about 6,672 hundred million won and top five lines with high inefficiency are Busan Line1, Daegu Line1, Daejeon Line1, Gwangju Line1, and Daegu Line2. The causes of inefficiency are attributable to labor and maintenance factors. The results of this study can be useful in case of finding the priorities of measures and specific plans for reducing labor and maintenance costs in the urban railway operation.

Estimation of Social Costs between the Main Transport Modes using Damage Function Approach (피해함수접근법을 이용한 주요운송수단의 사회적 비용 산정)

  • So, Aerim;Shin, Seungsik
    • Journal of Korea Port Economic Association
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    • v.28 no.4
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    • pp.1-37
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    • 2012
  • The purpose of this paper is to estimate the social costs induced by various transport modes such as truck, rail and sea vessel. For this purpose, we introduce the damage function of each transport modes, and estimate social costs for 10 items using Meta Analysis. As a results, this study can find that shipping is the most efficient transport mode because it gives the lowest social costs among them. This study also find that the iso-cost transport distance that gives the equal social costs between the transport modes. Our methodology can be thought somewhat inferior to the Contingent Valuation Methods, however the advantage of this methodology is that we can decomposite the total social costs into item by item and can apply it to other researches.

A Join Query with Aggregation functions Using Mapreduce (집계 함수를 포함하는 조인 질의의 맵리듀스를 사용한 효율적인 처리 기법)

  • Oh, So Hyeon;Lee, Ki Yong
    • Proceedings of the Korea Information Processing Society Conference
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    • 2015.04a
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    • pp.132-135
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    • 2015
  • 맵리듀스(MapReduce)는 분산 환경에서의 빅데이터(Big Data), 즉 대용량 데이터를 처리하는 프로그래밍 모델이다. 대용량의 데이터를 분석하기 위해서 집계 함수(Aggregation function)로 데이터를 처리할 수 있다. 본 논문에서는 맵리듀스 환경을 기반으로 SQL 쿼리에서 집계 함수를 더 적은 비용으로 수행하며 효율적으로 처리할 수 있는 두 가지 전략을 제안한다. 두 가지 전략 중 더 높은 성능을 보이는 전략을 더 효율적인 처리 방법으로 판단한다. 첫 번째 전략은 두 테이블을 Join하여 집계 함수를 처리하는 방법이다. 두 번째 전략은 집계 함수를 처리하여 Join에 참여할 튜플의 수를 최소로 줄인 후 Join을 수행하고 다시 집계 함수를 처리하는 방법이다. 두 제안 방법을 비교하기 위하여 실험을 한 결과 두 번째 전략이 더 적은 비용이 드므로 더 효율적인 처리 방법인 것으로 보인다.

A Performance Variation by Scaling Factor in NM-MMA Adaptive Equalization Algorithm (NM-MMA 적응 등화 알고리즘에서 Scaling Factor에 의한 성능 변화)

  • Lim, Seung-Gag
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.18 no.2
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    • pp.105-110
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    • 2018
  • This paper compare the adaptive equalization performance of NM-MMA (Novel Mixed-MMA) algorithm which using the mixed const function by scaling factor values. The mixed cost function of NM-MMA composed of the appropriate weighted addition of gradient vector in the MMA and SE-MMA cost function, and updating the tap coefficient based on these function, it is possible to improve the convergence speed and MSE value of current algorithm. The computer simulation was performed in the same channel, step size, SNR environment by changing the scaling factor, and its performance were compared appling the equalizer output constellation, residual isi, MD, MSE, SER. As a result of computer simulation, the residual values of performance index were reduced in case of the scaling factor of MMA cost function was greater than the scaling factor of SE-MMA. and the convergence speed was improved in case of the scaling factor of SE-MMA was greater than the MMA.