• Journal of Information Technology Services
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• v.8 no.2
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• pp.205-228
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• 2009

This paper examines how online product information changes the customers' purchase intentions from subjectivity-objectivity dichotomy perspective. Quality and Preference are proposed as product evaluation criteria and their marginal changes with product information differentiation are hypothesized. An experimental survey was conducted to 57 subjects and the hypotheses were partially supported through PLS path comparison method. The study contributes to IS research by proposing a simple and effective product evaluation framework and by abstracting the impact of product information from other factors. Finally, we suggest the utilization of product information with the optimization of the cost-benefit structure between information and purchase intention.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.37 no.3
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• pp.64-74
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• 2014

We show how a supplier can peg cost measures to the reliability of his time guarantees via the penalty costs considered in the framework. The framework also enables us to study the connections between the logistics network and the market. In this context, we show that even when the market base increases significantly, the supplier can still use the logistics network designed to satisfy lower demand density, with only a marginal reduction in profit. Finally we show how the framework is useful to evaluate and compare various logistics system improvement strategies. The supplier can then easily choose the improvement strategy that increases his profit with the minimal increase in his logistics costs.

• Computational Structural Engineering
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• v.8 no.4
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• pp.99-106
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• 1995

The General conceptual constitution of structural optimization is formulated and the algorithm using the gradient projection method and design sensitivity analysis is discussed. Examples of minimum-weight design for six-story steel plane frame are taken to illustrate the applicability of this algorithm. The advantages of this algorithm such as marginal cost and design sensitivity analysis as well as system analysis are explained.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.6
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• pp.259-264
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• 2006

This paper addresses the collusive bidding that functions as a potential obstacle to a fully competitive wholesale electricity market. Cooperative game is formulated and the equation of its Nash Equilibrium (NE) is derived on the basis of the supply function model. Gencos' willingness to selectively collude is expressed through a bargain theory. A Collusion Incentive Index(CII) for representing the willingness is defined through computing the Gencos' profits at NE. In order to keep the market non-cooperative, the market operator has to know the highest potentially collusive combination among the Gencos. Another index, which will be called the Collusion Monitoring Index(CMI), is suggested to detect the highest potential collusion and it is calculated using the marginal cost functions of the Gencos without any computation of NE. The effectiveness of CMI for detecting the highest potential collusion is verified through application on many test market cases.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.428-431
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• 2002

본 논문에서는 경쟁적 전력시장에서 송전제약에 관한 비용을 적절히 할당하는 방법을 제시하고자 한다. 혼잡비용을 할당하는 방법으로는 모든 사용자들에게 똑같이 배분하는 방법과 혼잡의 원인을 제공한 사용자에게 정도에 따라 가중하여 혼잡비용을 할당하는 nodal pricing과 zonal pricing이 있다. 계산의 신속성과 복잡성으로 인해서 zonal pricing이 유용한 방법으로 사용되고 있다. 기존의 분할 기술은 계통운영자가 설정한 한계범위의 모선들을 zone으로 형성하는 통계적인 방법을 사용했다. 이 방법은 운영자의 임의성이 반영되는 모호한 알고리즘이라는 단점을 가지고 있다. 그래서 본 논문에서는 한계비용민감도를 이용한 계통분할 방법을 제안하였다.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05b
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• pp.470-475
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• 1998

The marginal nuclear criticality analysis for the high density spent fuel storage at a PWR plant was carried out by using the HELIOS and CASMO-3 codes. More than 20 % of the calculated reactivity saving effect is observed in this analysis. This mainly comes from the adoption of some important fission products and B-10 in the criticality analysis. By taking burnup and boron credits, the high capacity of the spent fuel storage rack can be more fully utilized, reducing the space of storage. Larger storage for a given inventory of spent fuel should result in remarkable cost savings and mort importantly reduce the risks to the public and occupational workers.

• Journal of Dairy Science and Biotechnology
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• v.33 no.1
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• pp.69-73
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• 2015

The world is presently facing key challenges due to the population explosion, shortages in renewable sources of energy, and environmental problems. One important aspect of ecological intensification is the use and improvement of marginal lands and spaces often ignored, until now. Goats are known to be well adapted to scrubs, forage trees, and rangelands. Goats could contribute marginally, but significantly, to the growing demand for meat without using arable lands. Since 2000, there were 752 million goats globally, and goat livestock increased by 26.8% in 2010, accounting for 954 million heads. Goats are widespread due to their high adaptability to different environmental conditions and nutritional regimes, high productivity, and low maintenance cost. A significant growth in goat number was noticed in the period 2000~2010 in the Netherlands (+113.83%), in spite of the 9.75% decrease in EU-27. A cheese making goat farm in the Netherlands showed how it can survive in the one fifth size of the average. It may be a good model for the Korean goat industry since it uses seasonal breeding and results in reduced "goaty" flavor in the cheese.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.895-904
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• 2015

This paper presents a probabilistic approach of reliability evaluation and economic assessment for solving transmission network expansion planning problems. Three methods are proposed for TNEP, which are reorganizing the existing power system focused on the buses of interest, selecting candidates using modified system operating state method with healthy, marginal and at-risk states, and finally choosing the optimal alternative using cost-optimization method. TNEP candidates can be selected based on the state reliability such as sufficient and insufficient indices, as proposed in this paper. The process of economic assessment involves the costs of construction, maintenance and operation, congestion, and outage. The case studies are carried out with modified IEEE-24 bus system and Jeju island power system expansion plan in Korea, to verify the proposed methodology.

• Journal of Korean Institute of Industrial Engineers
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• v.22 no.1
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• pp.105-114
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• 1996

Telecommunication services are typically offered with two-part tariffs which consist of the access charges and the usage charges. In the previous analyses of optimal two-part tariffs, consumers have been assumed to be final users. In this paper, we take the telecommunication service as an input factor which is purchased by business consumers. We proposed a two-stage market model in which the good in queston is produced by an upstream monopolist and purchased as an input by firms and they sell their final outputs in a downstream market. We derive the optimal two-part tariffs of inputs in the case of oligopolistic downstream market with heterogeneous downstream firms. It is shown that two-part tariffs are more desirable than uniform prices from a welfare standpoint. It is also shown that if an upstream monopolist earns positive profits, usage charge is less than marginal cost in the optimal two-part tariffs.

• Proceedings of the KIEE Conference
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• 2002.11b
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• pp.111-113
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• 2002

본 논문에서는 경쟁적 전력시장에서 송전 계약에 관한 비용을 모선에서 한계비용 만감도를 이용해서 분할하는 방법을 제시하였다. 구조개편된 전력사장에서는 단순하면서도 분명한 전력 요금 시스템이 요구된다. Zonal pricing은 이런 면에서 좋은 pricing 시스템이 요구된다. 하지만, zone을 효과적으로 나누는 것은 상당히 어렵다. 기존의 방법에서는 오직 부하만을 고려하여 분류를 하였지만, 에너지 시장에서의 전력의 매매행위를 고려할 때, 시스템 내부의 모든 사업자에 대한 고려가 필요하다. 그래서, 본 논문에서는 한계비용 민감도를 이용해서 모든 에너지 시장 참여자를 고려하여, 네트워크를 분할하였다. 모든 노드에서의 민감도의 패턴이 분석되었고 동일한 패턴을 가진 노드들을 같은 zone으로 분류하였다. 6-모선 전력시스템을 이용해서 제안한 방법을 설명하였다.