• Journal of the military operations research society of Korea
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• v.36 no.3
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• pp.43-56
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• 2010

Recently, the acquisition environment of the Korean defense weapon system is emphasizing more the importance of cost analysis in terms of efficient execution for defense acquisition budget. While cost analysis, however, is emphasized in law and process, its infrastructures are still insufficient We have been using computerized cost models to obtain an estimate at early phase of project. But those models have been developed by foreign companies, and so they have many limitations when using in Korean defense environment. For this reason, it began to sympathize that we need the development of the Korean version cost estimation model suitable for our defense industry environment, and now many studies are proceeding. In this study, we suggest Cost Estimating Relationships(CERs) developing methodologies which is key logics of Korean version cost estimation model. Especially, we proposed a new CER's development process depending upon data characteristics such as, multicolinearity, outlier, small samples and heteroscedasticity. Also, we presented a case study for artillery weapon system using these methods we developed. We find that these CERs could be verified through theoretical methods.

• The KIPS Transactions:PartD
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• v.15D no.2
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• pp.207-212
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• 2008

This paper evaluates software cost estimation models, and presents the most suitable model. First, we transformed a relevant model into variables to make in linear. Second, we evaluated model's performance considering how much suitable the cost data of the actual development software was. In the stage of model performance evaluation criteria, we used MMRE which is the relative error concept rather than the absolute error. Existing software cost estimation model follows Weibull, Gamma, and Rayleigh function. In this paper, Gompertz function model is suggested which is a kind of growth curve. Additionally, we verify the compatability of other different growth curves. As a result of evaluation of model's performance, Gompertz function was considered to be the most suitable for the cost estimation model.

• Journal of Korea Port Economic Association
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• v.27 no.2
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• pp.85-110
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• 2011

The purpose of this study is to evaluate the social costs of inland trucking and maritime transport between Kwangyang Port in Korea and the Great Lakes in US. Also, this study compares these social costs each other, and finds the way how to internalize them for the efficiencies of national logistics policies. This study uses the Contingent Valuation Method to evaluate the social costs for the two transport modes in each country. The final result is that the social cost difference between inland trucking and maritime transport around US Great Lakes area is not so significant that there are not many chances to enhance the maritime transport in the region. However, in case of Korea, there is significant difference in social costs between the two transport modes, so that Korea government may have a lot of chances to improve the seaborne trade by way of various internalization policies.

• Journal of Digital Convergence
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• v.16 no.7
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• pp.89-96
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• 2018

In this paper, we proposed a parametric estimation method for estimating H/W cost by using the development data of professional service robot in Korea. In addition, we derived the factors and weights that we can estimate the costs depending on the application environmental conditions of the robot. For the analysis, we developed the equation of professional service robot cost estimation using parametric method. We also derived the adjustment factors and following weights through FGI and Delphi for environmental conditions. We have developed a cost estimation equation that reflects the weight, volume, and manufacturing difficulty, and can derive a relational equation that reflects the environmental factors(dust/water, heat/cold, safety, test, technology innovation). This provides an objective basis for estimating the cost of professional service robots and will lead to ongoing research for estimating the H/W development cost of professional service robots. In the future, we will increase reliability by collecting abundant data, and will strengthen models through finding functional factors.

• Journal of the Korean Society for Railway
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• v.16 no.4
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• pp.318-330
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• 2013

It is necessary to estimate the operating cost for constructing an urban railway system. The present study was thus carried out to develop an estimation function of the operating cost for a MRT(Medium-sized Rapid Transit) system. We selected seven independent variables that could influence the operating cost: the rolling stocks, the number of trains in operation, the length of the lines, the number of stations, the number of passengers per day, the frequency of train operation, and the number of depots. We performed a multiple regression using Excel. Three types of regression functions were thereupon developed. All of them proved to be appropriate after comparing the results of the estimated cost. It will therefore be possible to use one of these three types, depending on the assumptions of the independent variables.

• KDI Journal of Economic Policy
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• v.11 no.4
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• pp.23-38
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• 1989

본고(本稿)에서는 원화표시수입물가지수(貨表示輸入物價指數) 및 단위노동비용(單位勞動費用) 등의 비용요인(費用要因)과 GNP디플레이터로 표시한 물가(物價)와의 관계를 공적분검증방법(共積分檢證方法)으로 살펴보았는데 단위노동비용(單位勞動費用)과 물가간(物價間)에는 유의한 장기적(長期的) 균형관계(均衡關係)가 존재하나 이 관계식(關係式)에 수입물가지수(輸入物價指數)를 추가하기는 곤란한 것으로 나타났으며 수입물가지수(輸入物價指數)와 물가간(物價間)에도 유의한 장기적(長期的) 균형관계(均衡關係)를 발견하지 못하였다. 이에 따라 공적분(共積分)과 오차수정모형(誤差修正模型)을 사용하여 단위노동비용(單位勞動費用)만으로 인플레식(式)을 추정(推定)한 결과 그 적합도가 뛰어난 것으로 나타났다. 추정결과(推定結果)에 의하면 단위노동비용상승(單位勞動費用上昇)의 물가(物價)에 대한 영향은 영구적이며 최조 2년반 동안에 최대로 나타날 뿐 아니라 과도조정(過度調整)(overshooting)현상(現象)이 있는 것으로 나타났다. 이에 따라 비록 90년도의 임금인상(賃金引上)이 상당폭 둔화(鈍化)된다 하더라도 87년 하반기부터 시작된 단위노동비용급증(單位勞動費用急增)의 누적적 효과로 인하여 90년의 상당히 높은 인플레율은 불가피할 것으로 전망되었다. 마지막으로 이와 같은 물가상승압력(物價上昇壓力)을 완화하기 위해서 정책입안자(政策立案者)의 입장에서 본고(本稿)의 연구결과(硏究結果)에 대해 어떠한 해석이 가능한가를 논의하였는데, 정부(政府)의 정책입안자(政策立案者), 기업가(企業家) 및 근로자(勤勞者) 등 각(各) 경제주체(經濟主體)의 단합된 공동노력(共同努力)이 요구되는 것으로 지적되었다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.27 no.1
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• pp.103-108
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• 2023

We study the problem of selecting a subset of sensor nodes in sensor networks in order to maximize the performance of parameter estimation. To achieve a low-complexity sensor selection algorithm, we propose a greedy iterative algorithm that allows us to select one sensor node at a time so as to maximize the log-determinant of the inverse of the estimation error covariance matrix without resort to direct minimization of the estimation error. We apply QR factorization to the observation matrix in the log-determinant to derive an analytic selection rule which enables a fast selection of the next node at each iteration. We conduct the extensive experiments to show that the proposed algorithm offers a competitive performance in terms of estimation performance and complexity as compared with previous sensor selection techniques and provides a practical solution to the selection problem for various network applications.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.4
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• pp.1-9
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• 2019

Recently, in the space market, there has been a rapid reduction of the launch price. The major reason is that a few commercial companies, especially SpaceX, began to enter into the space market about ten years ago, which has changed the space market from monopolization to competition, and accelerated the adoption of commercial efficiency in the technology and management. Also, the successful landing and recovery of a first stage in 2016 by SpaceX proved to be a prelude to opening a new era of reusable launch vehicles, and SpaceX declared the groundbreaking launch price through using the reusable launch vehicle. This study calculates the total launch cost required to put a certain satellite into the LEO, compares the launch cost in three cases with different payload weights, and reviews the impacts of the payload on the cost effectiveness of a reusable vehicle. The total launch cost is divided into 6 subsections cost, namely development cost, production cost, refurbishment cost, operation cost, fixed-cost of factory and launch site, and insurance cost. The cost estimation relationships used in the calculation are taken from the commonly proven cost models such as TRANSCOST.

• 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.

• Journal of the Korean Geotechnical Society
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• v.30 no.3
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• pp.73-85
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• 2014

The strength parameters used in rock mass design are mainly estimated by equations using Hoek-Brown failure criterion because the tests to obtain the values are limited and expensive. To estimate the strength parameters, the Hoek-Brown failure criterion should be transformed to the Mohr-Coulomb failure criterion. But the processes are more or less cumbersome due to the several stages including the computation and the analyzing steps. In this study, several rock states of various conditions were modeled and then the strength parameters were estimated using the Hoek-Brown failure criterion. Thereafter by analyzing the results, some charts and equations estimating the strength parameters through only one step or easily in the field using the values of RMC, the uniaxial compressive strength and the rock constant ($m_i$), were suggested. And then the suggested method was compared and discussed with the existing method.