• Journal of the Korea Society of Computer and Information
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• v.11 no.2 s.40
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• pp.285-294
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• 2006

The requirements of Computer Supported Cooperative Work supporting efficient cooperative or collaborative works between multi-users have been increasing in distributed environments. The various technical sections such as group communication technology and distributed processing technology should be provided in Cooperative Work. The replicated development of Cooperative Work applications of a number of common requirements increases development costs enormously and duplicated investment parts. Therefore, systematical development environments are required to develop these common requirements and applications efficiently in Cooperative Work applications development. In this study, we propose the hierarchical role-based coordination model that improves the coordination model of legacy mobile agent to be appropriate in Cooperative Work applications, and design the development environment for Cooperative Work applications based on mobile agent. The proposed hierarchical role-based coordination model provides multi-layered group concepts of mobile agent, and enables implementation of efficient coordination policy per group. Additionally, it supports efficient Cooperative Work application development by role assignment per group unit.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.359-364
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• 2003

The loss of potential opportunity profit which is consisting in the partial markups of the corporation would taking placed in related with the time-delay deeply, has customarily disregarded in contract adjustment under the principles of denial of cost accounting method, declined conjecture in the point of benefits and protection of the law in scope of compensation and the restricted conditions of constant contract. It is being resulted from that the policies of the general principles of accounting standards which is subjected to ask an objective data and evidence, and the denial system as a debt derived from imperfect legal theory applied by current law. Therefore, it is necessitated to find if any irrationality in the positive system is and further to draw an improved reasonable measures to adopt by review of constant system preparing tile reasonableness with the method of suitable quantification devices provided that any time-delay is induced by the party.

• The Journal of Korean Association of Computer Education
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• v.9 no.2
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• pp.111-124
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• 2006

Multicast services are provided on the Internet in fast increasing. Therefore it is important to keep security for multicast communication. If a member of the group is removed, new group key has to be generated and distributed to all remaining members of group. Minimizing number of messages and operation cost for generation of the composite keys to be used to encrypting group key are important evaluating criteria of multicast key management scheme since generation and distribution of new keys for rekeying require expensive operation. Periodic batch rekeying can reduce these important parameters rather than rekeying sequentially in fashion one after another. In this paper, Hamming distance is calculated between every members to be removed. In batch rekeying the members with Hamming distance less than threshold are selected for rekeying procedure. With running the round assignment algorithm in the case of removing several members simultaneously, our scheme has advantages of reducing messages and operation cost for generation of the composite keys and eliminating possibility of collusion attack for rekeying. We evaluate performance of round assignment algorithm through simulation and show that our scheme is excellent after performance comparison of existent schemes and our scheme.

• International Area Studies Review
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• v.21 no.2
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• pp.143-169
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• 2017

This paper empirically examines how capital structure inertia varies across industries and there is different in industries, and whether this fact is explained by product market competition using non-financial firms listed in KOSP market over periods of 1981 to 2015. In empirical test, I find that firms with more competition environment tend to have inertia behavior in making decision of capital structure. This implies that it is explained by debt discipline effect and it is substitution for product market competitions. Also I find that manager tends to take action actively making decision of capital structure when product market competition is low. Also I show that they use debt to constraint the free cash flow. As a result, I conclude that Korean non-financial firms do not have more strong inertia behavior in capital structure rather than U.S. firms. Second, using OLS estimation, inertia effect disappears while there is strong inertia effect in relationship between inertia and product market competition. This result suggests that transaction cost is not key factor in explaining inertia behavior of capital structure.

• Korean Journal of Construction Engineering and Management
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• v.12 no.2
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• pp.3-11
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• 2011

There are several causes to recalculate the contract amount in public construction projects. Among them, the escalation clause was introduced in 1969 and now the condition to recalculate the cost is effective after 90 days from the date of contract and the rate of fluctuation should be more than 3% from the date of bidding. The two calculation methods for the rate of fluctuation are item-adjustment and index-adjustment. According to the results of investigation into 4 public institutions and 163 projects, all of them have used the method of index-adjustment and the rate of projects that spend over 6 months obtaining the approval of contract amount adjustment is more than 90%. The reason for spending lots of time is caused by problems of the calculation method on the price fluctuation rate. Therefore, it is necessary that the calculation method should be diversified to cope with the problems and a option of the builder should be expanded as well. Furthermore, if the way to apply correction factors to construction price index and average index based on the producer and consumer price index made by the bank of Korea is added, then the duration will be reduced without additional expenses. This study proposed the diversification of the calculation method using price fluctuation rate and builders' expanded options as improvement on the managerial method of Price Fluctuation System for the prompt and efficient contract amount adjustment.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10c
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• pp.371-374
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• 2007

본 논문에서는 고정 비용을 고려한 비선형 수송문제(Fixed Charge Non-linear Transportation Problem)에 대해 다룬다. 이는 한 종류의 상품을 다수의 공급처에서 다수의 수급처로 수송할 때, 총 수송비용과 고정 비용이 최소가 되도록 각 공급처와 수급처 간의 수송량을 결정하는 문제이다. 현재 비선형 수송문제에 대한 다양한 해법들이 제안되고 있으며 그 중에서도 메타 휴리스틱을 이용한 해법들이 가장 활발히 연구되고 있다. 본 논문에서는 메타 휴리스틱 방법들중에 가장 널리 이용되고 있는 유전 알고리즘을 이용한 해법을 제시하고자 한다. 유전 알고리즘을 적용함에 있어서 제일 첫 관문은 해의 유전자표현을 어떻게 나타낼 것인가이다. 본 논문에서는 수송문제의 해를 걸침나무로 표현할 수 있다는 점 에 착안하여 다양한 트리 표현법을 수송문제에 적용해 보고 수치 실험을 통해 그 성능에 대한 비교 연구를 한다.

• The Korean Journal of Financial Management
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• v.10 no.2
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• pp.1-51
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• 1993

본 논문의 목적은 첫째, 자본자유화로 인해 통화공급 구조가 이미 균형에서 이탈하여 심각한 수준의 불균형 상해에 있다는 점을 실증적으로 입증하고자 한다. 둘째, 자본유입에 따른 정책조정 비용을 감안한 통화정책 모형을 통해 주장에 대한 이론적 근거를 제시하고, 정책 조절에 수반되는 손실비용(損失費用)과 Mundell의 $\ulcorner$할당 문제(割當 問題)$\lrcorner$를 다시 조명해 보고자 한다. 세째, 자본유입에 따르는 문제점들을 해결할 수 있는 정책방안들을 Modigliani ar Miller의 명제(命題)에 입각한 새로운 각도에서 합리적 인 증시정책을 모색해 보고자 한다. 분석의 이론적 틀로서는 자본유입에 따라 수반되는 불확실성하의 정책조절 비용을 감안한 손실비용 최소화(loss cost minimization)를 통해, 통화 당국자는 총통화량을 정책적으로 내정된 목표값에 수렴시킨다고 가정하였다. 다른 한편, 자본유입에 따르는 문제점들을 통화시장에만 제한시키는 부분적(部分的) 균형분석(均衡分析) 대신, 이를 증권시장으로 직접 연계시켜 두 시장으로 확장된 틀을 활용하였다. 본 논문의 연구방법은 다음 두가지 측면의 접근식을 따랐다. 첫째, 자본자유화정책의 특성을 살펴보기 위해, 자본자유화 시점을 기준으로 삼아 과거 자본통제 시대의 $\ulcorner$사후적(事後的)인 중화정책(中和政策)$\lrcorner$에 의존하는 $\ulcorner$소극적(消極的)인 증권정책(證券政策)$\lrcorner$과 자본자유화시대의 $\ulcorner$사전적(事前的)인 상살정책(相殺政策)$\lrcorner$에 의한 $\ulcorner$거시적(巨視的)인 증권정책(證券政策)$\lrcorner$을 통해 고찰하는 비교분석론에 입각한 접근식을 택했다. 둘째, 외국자본의 유입동기(流入動機)를 문제해결의 시발점으로 삼아 이를 새로운 개방정책과 직결시켜 문제해결의 실마리를 풀어 보려는 선험적(先驗的) 접근식(接近式)을 택했다.

• Environmental and Resource Economics Review
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• v.24 no.4
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• pp.657-677
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• 2015

We employ a 3 regime-threshold vector error correction models (TVECM) to investigate the nonlinear dynamic adjustments of three marker crude oil prices such as WTI (West Texas Intermediate), Brent and Dubai. Especially we deal with 3 combinations of oil prices including WTI-Brent, WTI-Dubai and Brent-Dubai in order to analyze the dynamic adjustments of the prices based on the effects of the price spreads among these crude oil prices. Our daily spot prices data run from 2001.1.3 to 2014.12.31. We found that each combination is cointegrated over the period. WTI had dropped significantly in 2010 which had affected the movements of the spreads. To accomodate this fact, we divide the period into two sub-periods: 2000.1.3-2009.12.31 and 2010.1.1-2014.12.31. It is found that each combination is cointegrated in both sub-periods. Moroever, in the first sub-period, all three oil prices are shown to follow nonlinear dynamic adjustments. In the second sub-period, however, TVECM is better than VECM(vector error correction model) for WTI-Dubai and Brent-Dubai while VECM performs better for WTI-Brent. The transaction costs are estimated to be reduced for the second sub-period for WTI-Dubai and Brent-Dubai compared to the first sub-period.

• Journal of the Korean Vacuum Society
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• v.10 no.2
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• pp.145-154
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• 2001

A new type of modular mirror manipulator with independent adjustability was developed for the EPU6 beamline under construction at the Pohang Accelerator Laboratory. The mirror manipulator was designed so that the angular displacements of roll and pitch rotations do not introduce translational displacements and are independent with each other by positioning the mirror center to the center of a newly devised spherical joint. Manipulating its roll and pitch micrometers, the rotation angles of a dummy mirror were measured at an accuracy of 5 $\mu$rad using a gravity-referenced inclinometer. While the designed angular resolution was 3.937 $\mu$rad/$\mu\textrm{m}$, measured angular resolutions were 3.94 $\mu$rad/$\mu\textrm{m}$ for roll rotation and 3.85 $\mu$rad/$\mu\textrm{m}$ for pitch rotation. The effect of roll rotation on pitch angles was measured to be -3.18% and the effect of pitch rotation on roll angles was measured to be -5.21%. As the mirror manipulator was designed with emphases on independent adjustability and standardization, it results in eases of manufacturing, installation and adjustment as well as reductions of development period and design cost of mirror manipulators for various types of mirrors.

• Management & Information Systems Review
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• v.32 no.5
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• pp.261-285
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• 2013

In this paper, examined relationship between Earnings Management and Conservatism. For analysis of this purpose, we applied the Earnings Loss Avoidance Firms and Big-bath Firms. The results are as follows. First, conservative of Earnings Loss Avoidance Firms(sample I, II) is lower than the controlled companies. And Big-bath firms(sample III, IV) is higher than the controlled companies. This is a negative relationship between conservative and earning management. These results are consistent with previous research results. Second, When analyzing the Earnings Loss Avoidance Firms(sample I, II), Results are presented that conservative and earning management related to positive. These results reflect the company to Investors' demand for conservatism.