• 한국항해학회지
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• 제20권3호
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• pp.43-63
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• 1996

The purpose of this study is to find out what is the functional role of VTS in order to get the people concerned with marine traffic/transportation understand about VTS. VTS could be described as the essential risk management system in both cost effective on cost-benefit analysis and the sea space or time management at port, coastal environment. The important role of the VTS are those functions such as the decision making infrastructure, the passive/active safety measures at sea. VTS could not control/regulate marine traffic as strong as ATC(Air Traffic Control) owing to the marine traffic characters. However, the right and responsibility of VTS finally are belong to the master, pilot and mariners. For the benefit of the electronic technology development, VTS system also cloud be upgraded to communication system from information system. In connection with these system upgrading, the right and responsibility of VTS/staff should be supported by domestic legal system. The followings are presented for VTS to be effective. First, the cooperation and understanding of VTS between the peoples concerned with marine traffic/transportation are essential. Because they are all data supplier and also information consumers. Second, VTS staff/regulator should be selected, educated, trained accordingly as per their career, ability, quality, qualification, certification and etc. Third, the port reliability from VTS users depends on the factors such as economic interests, safety and effectiveness/efficiency of VTS.

• Journal of Information Technology Applications and Management
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• 제24권1호
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• pp.93-110
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• 2017

This study aims at classifying and analyzing the business models of reverse overseas direct purchasing through online shopping-malls. After analyzing the current status of the reverse overseas direct purchasing online markets, this study identifies relevant critical business factors and synthesizes prior studies to construct and analyse the business models. This study proposes that the business models can be classified into five types according to the operation modes and three types according to the delivery methods. So theoretically 15 business models can be identified. For each business model this study analyzes the characteristics and the pros & cons. It also suggests deployment strategies for companies by considering cost reduction, brand establishment, customer management, customer aquisition, and easiness from the business perspective. From the customers perspective, cost reduction, reliability, royalty, ease to purchase, and accessibility can be considered according to the types of operation mode. The main contribution of this study is to provide the basic classifications and structures of reverse overseas direct purchasing business models systematically. As the result, our study evaluates the business models that which one is better than others in a situation in terms of company and customer. Lastly, we talk about limits and future prospects of the study.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2000년도 추계학술발표대회 논문집
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• pp.245-248
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• 2000

Modern aircraft composite structures are designed using a damage tolerance philosophy. This design philosophy envisions sufficient strength and structural integrity of the aircraft to sustain major damage and to avoid catastrophic failure. The only reasonable way to treat on the same basis all the conditions and uncertainties participating in the design of damage tolerant composite aircraft structures is to use the probability-based approach. Therefore, the model has been developed to assess the probability of structural failure (POSF) and associated risk taking into account the random mechanical loads, random temperature-humidity conditions, conditions causing damages, as well as structural strength variations due to intrinsic strength scatter, manufacturing defects, operational damages, temperature-humidity conditions. The model enables engineers to establish the relationship between static/residual strength safety margins, production quality control requirements, in-service inspection resolution and criteria, and POSF. This make possible to estimate the cost associated with the mentioned factors and to use this cost as overall criterion. The methodology has been programmed into software.

• Journal of Electrical Engineering and Technology
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• 제7권2호
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• pp.141-150
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• 2012

The present study examines an efficient congestion management system compatible with the evolving environment. The key is to build an information model shared and exchanged for marketbased solutions to alleviate congestion. Traditional methods for congestion management can be classified into two categories, i.e., the centralized scheme and the decentralized scheme, depending on the extent to which the independent system operator (ISO) is involved in market participants' (MPs) activities. Although the centralized scheme is more appropriate for providing reliable system operation and relieving congestion in near real-time, the decentralized scheme is preferred for supporting efficient market operation. The minimum set of information between the ISO and MPs for decentralized scheme is identified: i) congestion-based zone, ii) Power Transfer Distribution Factors, and iii) transmission congestion cost. The mathematical modeling of the proposed information is expressed, considering its process of making effective use of information. Numerical analysis is conducted to demonstrate both cost minimization from the MP perspective and the reliability enhancement from the ISO perspective based on the proposed information exchange scheme.

• 보건행정학회지
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• 제3권1호
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• pp.84-101
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• 1993

The current method of rate adjustment is based on the evaluation of the financial performance of hospitals. The method has the disadvantages such as too complicated, expensive process as well as low reliability due to small sample size. This study, therefore, develops a new model for the rate adjustment with the use of the composite index. In addition to that, it examines the validity of the model by comparing the result of the new method with that of the conventional method. The idea of the new model comes from the Medicare Economic Index(MEI) on which physician fees for the Medicare patients are adjusted periodically in the United States. Medical costs are classified into three groups : labor costs, materials and other expenses. Labor costs are subdivided into physicians and other personnels. Materials are subdivided into drugs and others. Other expenses are subdivided into 5 items. Macro economic indices are selected for each cost item in order to reflect the cost inflation during the specific period. Then the composite index which integrate all items according to the ration of each item in the total costs is calculated. The result from the application of empirical data to the new model is very similar to that of the current method. Furthermore, this method is very simple and also to easy to get social concensus. This model can be replaced the current method based on the analysis of the financial performance for the adjustment of medical fees.

• 한국항공우주학회지
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• 제45권6호
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• pp.498-507
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• 2017

최근 우주용 전장품에 다양한 실장형태의 고집적 소자가 적용됨에 따라, 기계적 환경에서의 고신뢰성 확보를 위해 인증모델 제작 전 잠재적 위험요소에 대한 조기진단으로 개발기간 및 비용 절감이 가능한 설계절차 구축이 요구된다. 고신뢰도 전장품 설계를 위해 기존에 적용되어온 Steinberg의 피로파괴이론은 최근 다양한 크기와 실장기법의 소자를 갖는 우주용 전장품에 적용하기에는 이론적 한계와 이들 각각에 대한 모델링 기법에 따라 상이한 결과가 도출되는 등의 한계가 존재한다. 이를 해결하기 위해 소자의 상세 유한요소모델을 구축할 시, 다수의 실장구조를 갖는 고집적화 기판을 모델링하기에는 많은 시간이 소요되는 단점이 존재한다. 본 논문에서는 고신뢰도 전장품 설계기법 구축을 위해 기존 사업에서 적용된 설계와 다른 접근방법의 일환으로 상용 신뢰성 수명예측 도구인 Sherlock을 이용하여 차세대중형위성용 탑재 전장품인 CCB(Camera Controller Box)에 대한 인증시험수준에서의 고장 메커니즘 별 신뢰성 평가를 수행하였다.

• 패션비즈니스
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• 제21권1호
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• pp.112-123
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• 2017

This study investigated if there are differences between Korean and Chinese consumers among the determinants of consumer complaint intention, type of complaint intention, and traits of complaining behavior. Sample subjects used in this study were female college students in Jeollabukdo and Jeollanamdo, Korea and Yunnam, China. Questionnaire data from 780 college students(Korea: 441, China: 339) were analyzed through a reliability analysis, factor analysis, frequence, mean, and multiple regression analysis. The results of the study were as follows. First, complaint intention of college students was divided into 3 factors, voice, private, and third party. Second, the findings of regression analysis for the total sample showed that the determinants of the factor 'voice' were the country, salespeople, product involvement, complaint cost, psychological tension, and social benefit. Whereas, the determinants of the factor 'private' were the producer, product involvement, psychological tension, and social benefit. Also, the determinants of the factor 'third party' were the country, oneself, salespeople, complaint cost, personal norms, and social benefit. Third, significant differences were indicated in the determinants of the 'voice', 'private' and 'third party' factors of complaint intention between Korean and Chinese consumers. Fourth, the complaint intention factors of 'voice' and 'third party' of Chinese consumers were higher than Korean consumers. Fifth, the attributions to dissatisfaction of Korean consumers were higher than Chinese consumers, and the product involvement, possibility for success, and consumer complaint attitudes of Chinese consumers were revealed to be higher than Korean consumers.

• 연구논문집
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• 통권27호
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• pp.87-99
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• 1997

Present paper describes on/off design performance of a 50KW turbogenerator gas turbine engine for hybrid vehicle application. For optimum design point selection, relevant parameter study is carried out. The turbogenerator gas turbine engine for a hybrid vehicle is expected to be designed for maximum fuel economy, ultra low emissions, and very low cost. Compressor, combustor, turbine, and permanent-magnet generator will be mounted on a single high speed (82,000 rpm) shaft that will be supported on air bearings. As the generator is built into the shaft, gearbox and other moving parts become unnecessary and thus will increase the system's reliability and reduce the manufacturing cost. The engine has a radial compressor and turbine with design point pressure ratio of 4.0. This pressure ratio was set based on calculation of specific fuel consumption and specific power variation with pressure ratio. For the given turbine inlet temperature, a rather conservative value of $1100^\circK$ was selected. Designed mass flow rate was 0.5 kg/sec. Parametric study of the cycle indicates that specific work and efficiency increase at a given pressure ratio and turbine inlet temperature. Off design analysis shows that the gas turbine system reaches self operating condition at N/$N_{DP}$ = 0.53. Bleeding air for turbine stator cooling is omitted considering low TIT and for a simple geometric structure. Various engine performance simulations including, ambient temperature influence, surging at part load condition. Transient analysis were performed to secure the optimum engine operating characteristics. Surge margin throughout the performance analysis were maintained to be over 80% approximately. Validation of present results are yet to be seen as the performance tests are scheduled by the end of 1998 for comparison.

• 한국터널지하공간학회 논문집
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• 제5권3호
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• pp.241-250
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• 2003

암반은 그 특성상 매우 불균질하며, 조사 및 시험을 통하여 얻을 수 있는 자료는 아주 한정적이다. 이러한 이유 때문에 암반 중에 구조물을 구축하는 작업은 많은 불확실성 (uncertainties)을 내포하게 된다. 터널 설계에 있어서 주요 설계 파라미터인 지보패턴, 굴진장 및 굴착방법 등은 최적의 값으로 결정되어야 하나 그 결정이 쉽지 않으며, 결정을 잘못할 경우 원하지 않는 risk, 즉 터널 안정성의 저하 혹은 지보재의 지나친 보강으로 인한 경제적 손실을 발생시킨다. 본 연구에서는 터널설계 시 주요한 설계 파라미터인 지보패턴 및 굴진장을 위험도 분석 기법에 근거하여 결정하는 방법을 소개하였다. 지보량이 증가할수록 신뢰지수가 증가하여 터널의 안정성이 증가함을 정량적으로 확인할 수 있었으며, 터널의 붕괴 등으로 말미암아 발생할 수 있는 손실비용 및 공사비를 고려하여 위험도 분석을 실시함으로서 최적의 지보패턴 및 굴진장을 정량적으로 결정할 수 있었다.

• 한국해안·해양공학회논문집
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• 제22권3호
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• pp.191-201
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• 2010

방파제는 인명 피해의 우려가 적은 구조물이기 때문에 주로 비용 최적화를 고려하여 설계한다. 하지만 대부분의 국내 방파제는 비용최적설계를 고려하지 않았다. 본 연구에서는 비용최적설계를 국내의 경사식 방파제에 적용하여 최적설계중량과 목표파괴확률 그리고 부분안전계수를 산정하였다. 사용한 방법은 PIANC Working Group 47의 Hans F. Burcharth and John D. Sorensen에 의해 개발된 것이다. 최적재현기간은 많은 경우에 50년으로 계산되었고 실질이자율이 높을 경우에 100년으로도 계산되었다. 최적재현기간에 해당하는 파괴확률과 기존 구조물의 신뢰성 해석에서 얻은 파괴확률을 사용하여 목표파괴확률을 제안하였다. 국내 설계기준인 초기한계상태의 최종적인 목표파괴확률은 약 60%이며 이에 상응하는 전체안전계수는 1.09이다. 이는 현행 설계법보다 9% 큰 공칭직경과 30% 큰 설계중량을 요구한다. 또한 비용최적설계를 고려한 부분안전계수를 산정하여 비용을 고려하지 않는 Level 2의 부분안전계수와 비교하였고 목표파괴확률이 40% 미만일 때 두 방법이 비교적 잘 일치함을 보였다.