• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.7
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• pp.429-436
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• 2003

This paper presents a new approach for evaluating the transmission marginal loss factors (MLFs) considering the reactive power. Generally, MLFs are represented as the sensitivity of transmission losses, which is computed from the change of the generation at reference bus by the change of the load at the arbitrary bus-i. The conventional evaluation method for MLFs uses the only H matrix, which is a part of jacobian matrix. Therefore, the MLFs computed by the existing method, don't consider the effect of the reactive power, although the transmission losses are a function of the reactive power as well as the active power. To compensate the limits of the existing method for evaluating MLFs, the power factor at the bus-i is introduced for reflecting the effect of the reactive power in the evaluation method of the MLFs. Also, MLFs calculated by the developed method are applied to energy spot markets to reflect the impacts of reactive power. This method is tested with the sample system with 5-bus, and analyzed how much MLFs have an effect on the bidding/offer price, market clearing price(MCP), and settlement in the competitive energy spot market. This paper compared the results of MLFs calculated by the existing and proposed method for the IEEE 14-bus system, and the KEPCO system.

• Proceedings of the KIEE Conference
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• 2005.11b
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• pp.162-164
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• 2005

This paper presents an hour-ahead System Marginal Price (SMP) forecasting framework based on a neural network. Recently, the deregulation in power industries has impacted on the power system operational problems. The bidding strategy of market participants in energy market is highly dependent on the short-term price levels. Therefore, short-term SMP forecasting is a very important issue to market participants to maximize their profits. and to market operator who may wish to operate the electricity market in a stable sense. The proposed hybrid neural network is composed of tow parts. First part of this scheme is pattern classification to input data using Kohonen Self-Organizing Map (SOM) and the second part is SMP forecasting using back-propagation neural network that has three layers. This paper compares the forecasting results using classified input data and unclassified input data. The proposed technique is trained, validated and tested with historical date of Korea Power Exchange (KPX) in 2002.

• Journal of the Korea Safety Management & Science
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• v.18 no.3
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• pp.17-24
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• 2016

The regulation for industrial accident rate level assessment of construction companies was introduced to the construction industry in the Republic of Korea since 1993 and has brought positive outcome on industrial accidents reduction at construction work sites. There were considerable decrease of industrial accident ratio and enforcing of contrators' safety organizations from the beginning of the regulation for industrial accident rate level assessment. In spite of these positive outcomes, there were some negative effects such as contractors' shrinking accident reports to keep good accident ratios since these figures had a great impact on pre-qualification stage of bidding when general contractors were competing for new construction projects. In addition, Comprehensive evaluation bid system, which replaces the lowest price bid system is applied to government-ordered construction projects since 2016. Comprehensive evaluation bid system includes construction company's accident rate as one of the evaluation items and carries out with the industrial accident rate level assessment of construction companies at the same time. The regulations of two systems have been called for improvement to unify these different procedures and standards which have led business stakeholders to confusion for several years. This study aims to devote on lessening shrinking accident reports and to reduce the waste of business stakeholders through changing the regulation for industrial accident rate level assessment.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.987-990
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• 2007

Warranty contracting is contracting methods that European Countries have applied to asphalt pavement projects from long ago, and in America as the expected effects of the warranty contracting are being verified to introduce it, the number of projects with warranty is being increased rapidly. In Japan, the warranty contracting suitable for Japanese style was established and is being applied. This study investigated and analyzed the present state of the warranty contracting being applied to European countries, America and Japan, and suggested advantages and disadvantages in introducing the warranty contracting into Korea and directions to introduce it. The principal result of this study is that performance bond contract system, performance surety bond system and performance bidding system should be established to introduce the warranty contracting into Korea.

• International conference on construction engineering and project management
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• 2011.02a
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• pp.399-406
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• 2011

Various construction bonds and warranties critically burden the general contractor. Also, sporadic or cumulative delays of progress payment by the owner can further trap the contractor in a financial quagmire. Facing the possibility of cash flow deficiency and callous response from the banks, most construction firms may become financially incapable of market competition, and attractive project tenders become a bidding game among few deep-pocket players. The downside of such market environment is that the depth of pocket, rather than that of professional competency dictates the choice of market winners. In Taiwan, this has been a potential crisis to the construction industry after the financial crisis which started out since 2008. To encounter this problem, this research will examine the means to better manage the construction industry. Essentially, a credit guarantee system (CGS) is the prime solution to strengthen a bank's confidence in any particular construction firm. Thus establishing a national platform which evaluates and rewards a construction firm's overall credibility is pivotal, and this third-party rated credit can help a bank to render a loan more wisely. Finally, this paper will propose the ideal operating schemes of construction-specific CGS in Taiwan and a credit scoring prototype model for construction industry, as reference for the government and banks, respectively.

• Journal of Bio-Environment Control
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• v.5 no.2
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• pp.174-186
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• 1996

This study was carried out in order to understand the plan, design, constructing and actual condition of management of modernized horticultural facilities in Kyungpook Province which had been constructed from 1992 to 1995 funded by Government support. The aim of this study is to provide reference data for success of the forth project. It was performed by making up a question about driving of project and management condition of equipment after constructing. The results obtained from this study are as follows: 1. 73.5% of facilities horticulture farmhouse recognized that the prospect of greenhouse is bright, but 92.5% of the farmhouse also recognised that they need technical consultation on protected horticulture farming. Therefore, technical educations would must be enhanced about foundation of greenhouse and cultivation technique. 2. The holding times of explanatory meetings, cause of understanding to farmhouse, were one or two times in greenhouse construction, and 62.5% of the farmhouse expressed the insufficiency at the explanation and educational data. For this reason, it was judged that the construction contract had been delayed more than 5 months in 49.3% of the farmhouse after the decision of project budget. 3. In constructing after a contract, the rates of construction delay is 53.4% and defect occurrence is 41.1%. The biggest reasons of construction delay was insufficiency of worker and materials supply. Each percentage is 29.1%. And the reason of defect occurrence is badness of machinery equipment(62.9% ). 4. In management of greenhouse, a pipe-constructed plastic film greenhouse changes plastic film every one and three years because of sticking dust on plastic film. It was needed to about in cleaning technique of coverings. Because that used 3-5 years only half of the expected life span. 5. The order of broken rating in the subsidiary equipment is like this lollop ventilator (42.8%), a general control system(33.3%) especially, in the case of a general control system, the rate of all family can control is 52.7%. so, it is time to develop easy control equipment which every one could use as soon as possible. 6. When choose heat generator as decide capacity, the most priority is the mount of heat generator the percent is 45.5% heat generator and as decide model, the private purchase's percent is 77.3%. It is higher than a public bidding heat generator the percent is 22.7% heat generator when it compare with a public bidding. In the case of $CO_2$ generator, using rate is only 19.0%. The using rate is very low, so it needs education how to use depends on the way of the subsidiary equipment. 7. In the case of seedlings, it is asked to use factory-processed seedling effectively. because it's difficult to get security of labors(58.8%), hoped crops (55.9%) access same crops(29.4%) much more and changing of crops depends on market situation. that is the main reason the lack of knowhow.

• KIISE Transactions on Computing Practices
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• v.23 no.6
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• pp.359-370
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• 2017

In overseas-hospital construction, the digital hospital is a trend that is based on the developments of the information and communication technologies, state-of-the-art medical equipment, smart health, and telemedicine. Along with the increasing proportion of IT, this has resulted in the spreading of the concept throughout city-like hospitals and their transformation into digital hospitals. In the hospital-construction business, IT is a key element that will link the modernization of the mechanical, electrical, and equipment systems, construction, and medical equipment for efficiency maximization through integration. The purpose of this study is the analysis of the market-expansion success factors through the construction of a success-story-based, IT-driven overseas-hospital business. The digital-hospital concept and the development process are analyzed through a literature review, and the success factors are analyzed in terms of the cost, time, and quality that are proposed in the project-management body of knowledge. The main contributions of this study regarding the success factors are as follows: First, a cost-side need exists regarding the establishment of strategic-value engineering in terms of increasing the value from the perspectives of the IT and operational infrastructures; second, in terms of the construction time, all of the hospital systems must comply with the established deadlines for the integrated test and commissioning; and lastly, in terms of quality, it is important to ensure that the System Integration digital-hospital services are delivered according to the user requirements.

• Journal of the Korean Home Economics Association
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• v.42 no.2
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• pp.117-131
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• 2004

The purpose of this study was to examine the current situation of B2B fashion buying behavior (i.e., buying motives, product characteristics, buying processes), and to analyze the buying performance, buying problems and buying strategies. In depth, face-to-face interviews with structured questionnaire were conducted with three buyers and three vendors related to 18 buying items of C Company. Results of this research were as following:1. Buying motives were mainly reduction of buying costs, improvement of profits, and increased efficiency in buying process for retail buyers, while the selling motive was mainly improvement of market share for suppliers. Suitable items for B2B buying were basic items or bulk items. The B2B buying process included the following steps: selecting auction items, target prices, and suppliers ; setting the product specification and bidding niles; training the suppliers for preparing the auction; proceeding the auction by internet. 2. The perceived B2B benefits for buyers were profit improvement and cost reduction while those for suppliers were time saving and market share improvement. The indicated buying problems were as poor product quality, low product image, and difficulty in partnership. For B2B buying strategies, a quality management system, various auction tactics based on items, and a supplier management system were recommended.

• KIEE International Transactions on Power Engineering
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• v.5A no.4
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• pp.331-338
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• 2005

In this paper, an improved maintenance scheduling approach suitable for the competitive environment is proposed by taking account of profits and costs of generation companies and the formulated combinatorial optimization problem is solved by using Reactive Tabu search (RTS). In competitive power markets, electricity prices are determined by the balance between demand and supply through electric power exchanges or by bilateral contracts. Therefore, in decision makings, it is essential for system operation planners and market participants to take the volatility of electricity price into consideration. In the proposed maintenance scheduling approach, firstly, electricity prices over the targeted period are forecasted based on Artificial Neural Network (ANN) and also a newly proposed aggregated bidding curve. Secondary, the maintenance scheduling is formulated as a combinatorial optimization problem with a novel objective function by which the most profitable maintenance schedule would be attained. As an objective function, Opportunity Loss by Maintenance (OLM) is adopted to maximize the profit of generation companies (GENCOS). Thirdly, the combinatorial optimization maintenance scheduling problem is solved by using Reactive Tabu Search in the light of the objective functions and forecasted electricity prices. Finally, the proposed maintenance scheduling is applied to a practical test power system to verify the advantages and practicability of the proposed method.

• Journal of Digital Convergence
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• v.17 no.4
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• pp.29-39
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• 2019

This paper understands small and medium-sized enterprises(SMEs) with the lenses of 'labors' and 'technology' and analyzes possible alternatives for creating jobs in Korea. Interviews with eighty CEOs, directors, managers are conducted during the summer in 2017. In terms of 'labors,' critical issues were 'low income' and 'income gap from conglomerates.' When it comes to 'technology,' support for R&D was critically presented. This study proposes three policies for creating jobs: 1) National Management for Good Technicians, 2) Technical Bidding System, and 3) Mutual benefit disclosure System. Implications for the employment policy are followed.