• 대한기계학회논문집B
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• 제33권4호
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• pp.255-263
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• 2009

The most concerning issue of these days is the energy crisis caused by increasing threat of dependence on imported oil and volatile market trend. Under these circumstances, the PHEV(plug-in hybrid electric vehicle) is drawing attention for the next generation's car which could give a chance to decrease the dependence on imported oil and reduce the environmental impact of vehicle. The fueling cost of PHEV, one of the core factor of decision about buying car, should be calculated in the circumstances of Korea to make sure that PHEV has competitive power in real market. The fuel cost saving of PHEV versus CV(conventional vehicle) is simulated and discussed in the condition of increasing gasoline cost, electricity rate, and city-gas rate. In conclusion, the PHEV60-FS shows the best economic feasibility when gasoline price goes up. The PHEV20 has the most stable economic feasibility as electricity rate increases. The fuel cell cogeneration system for RPG could be an alternative for charger of PHEV in the near future.

• Structural Engineering and Mechanics
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• 제59권5호
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• pp.933-950
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• 2016

Decks, interior beams, edge beams and girders are the parts of a steel floor system. If the deck is optimized without considering beam optimization, finding best result is simple. However, a deck with higher cost may increase the composite action of the beams and decrease the beam cost reducing the total cost. Also different number of floor divisions can improve the total floor cost. Increasing beam capacity by using castellated beams is other efficient method to save the costs. In this study, floor optimization is performed and these three issues are discussed. Floor division number and deck sections are some of the variables. Also for each beam, profile section of the beam, beam cutting depth, cutting angle, spacing between holes and number of filled holes at the ends of castellated beams are other variables. Constraints include the application of stress, stability, deflection and vibration limitations according to the load and resistance factor (LRFD) design. Objective function is the total cost of the floor consisting of the steel profile cost, cutting and welding cost, concrete cost, steel deck cost, shear stud cost and construction costs. Optimization is performed by enhanced colliding body optimization (ECBO), Results show that using castellated beams, selecting a deck with higher price and considering different number of floor divisions can decrease the total cost of the floor.

• 한국컴퓨터정보학회논문지
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• 제23권6호
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• pp.59-66
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• 2018

Recently, the use of mobile payment, called "Pay" payment, is increasing such as 'KakaoPay' and 'SamsungPay'. In Korea, various mobile payment services are running and emerging. The purpose of this study is to examine the intention to switch from using existing credit cards or check card to mobile payment service based on the two-factor theory. We empirically examined the effect of the two factors, the factors that enable switching and the factors that inhibit switching. Therefore, the study use switching cost and switching benefit as parameters to confirm the effect on the switching intention. In addition, this study intends to analyze the differences between two subgroups by the degree of personal innovativeness. We survey smartphone users and credit card or check card users, and analyzed the Smart PLS 3.0 using structural equation model to verify the significance of the research hypothesis.

• 무역학회지
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• 제47권2호
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• pp.19-29
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• 2022

This study evaluated the importance of automobile procurement logistics using AHP. Although automobile procurement and logistics is represented by JIT, internal and external risk factors for the automobile and logistics industries are increasing, so it is necessary to re-evaluate them and establish countermeasures. Therefore, this study conducted AHP analysis targeting 30 automobile procurement and logistics experts. Through previous studies and interviews, 4 factors for Tier 1 and 12 factors for Tier 2 were derived. As a result of AHP, the logistics factor was analyzed as the most important and the cost factor was less important than the other factors. This means that supply chain operation is more important than cost, and it is analyzed that stopping all supply chain participants is more damaging than logistics or inventory costs. Such research can provide implications not only for the automotive supply chain but also other industries with similar characteristics, and it is considered to be a meaningful study at the present time when the global supply chain is being reorganized.

• 전기학회논문지
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• 제57권4호
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• pp.560-566
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• 2008

Today, as the power trades between generation companies and power customer are liberalized, the uncertainty level of operated power system is rapidly increased. Therefore, transmission operators as decision makers for transmission expansion are required to establish a deliberate investment plan for effective operations of transmission facilities considering forecasted conditions of power system. This paper proposes the methodology for the optimal solution of transmission expansion in deregulated power system. The paper obtains the expected value of transmission congestion cost for various scenarios by using occurrence probability. In addition, the paper assumes that increasing rates of loads are the probability distribution and indicates the location of expanded transmission line, the time for transmission expansion with the minimum cost for the future by performing the Montecarlo simulation. To minimize the investment risk as the variance of the congestion cost, Mean-Variance Markowitz portfolio theory is applied to the optimization model by the penalty factor of the variance. By the case study, the optimal solution for transmission expansion plan considering the feature of market participants is obtained.

• 한국사회복지학
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• 제52권
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• pp.117-141
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• 2003

본 연구는 부산지역 사회복지관의 투입 요소와 산출 요소간의 효율성의 관계를 분석한 연구이다. 사회복지관의 효율성 평가를 위해 비영리기관에서 많이 활용되고 있는 자료포락분석(DEA)을 사용하였으며, 자료는 2001년 부산광역시에 제출한 사업보고 자료를 활용하였다. 본 연구에서는 4가지 다른 모델을 설정하여 부산지역 전체 45개 기관을 전수조사 하였다. 4가지 모델을 보면, 전 모델의 산출은 연간 프로그램 이용자의 연인원을 중심으로 투입의 변수에 따라 모델을 구분하였다. 모델 1; 투입에 사회복지사의 인력 수와 사회복지사 인건비, 모델 2; 투입에 총 직원 수, 연간 총 운영비, 모델 3; 투입에 총 직원 수, 연간 자원봉사자 수, 운영기간, 모델 4; 투입에 총 직원 수, 연간 자원봉사자 수, 운영기간, 연간 총 운영비를 설정하여 효율성을 분석하였다. 본 연구의 결과는 다음과 같다. (1) 전체 45개 사회복지관에서 35-55%만이 상대적으로 효율적인 사회복지관으로 평가되고 있는 것으로 나타났다. 각 모델별로 평균 효율치를 살펴보면, 모델 1은 .8735, 모델 2는 .7048, 모델 3은 .4941, 모델4는 .5097로 나타났다. (2) 모든 기관이 효율이 가장 높은 효율점수 1이 되기 위해서 어떻게 변화되어야 하는가를 산출물을 기준으로 하여 모델 1, 2, 3, 4로서 살펴보았다. 사회복지기관에서 주요한 투입변수인 인력과 예산부분에 있어서 어느 정도의 변화가 필요한지를 모델 1, 2, 3, 4를 전체적으로 살펴본 결과 인력과 예산부분에 있어서 변화가 필요한 기관이 전체 45곳 중 41곳이었으며 이 기관은 모두 현재보다 인력이나 예산부분의 증가를 요구되는 것으로 나타났다. 이 중에서도 인력적인 부분과 예산부분의 증가가 모두 필요한 기관은 보강이 필요한 41기관 중 60%에 해당하는 25곳이었으며, 예산의 증액만 요청되는 기관은 6곳, 인력의 보강만 필요한 기관은 10곳으로 나타났다. 따라서 부산지역의 대부분의 사회복지기관이 현재의 산출량에 대해 가장 효율적으로 운영되기 위해서는 개별기관별로 예산과 인력의 보강이 필요한 것으로 나타났다.

• 품질경영학회지
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• 제49권2호
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• pp.213-231
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• 2021

Purpose: This study intends to provide decision-making information to improve efficiency by analyzing the management efficiency of smart greenhouse business entities and identifying factors that affect the efficiency based on input and output. Methods: The subjects of analysis were business entities for cultivating strawberries in smart greenhouses in Jeolla region (northern and southern Jeolla provinces), and the analysis focused on the management performance of the 2019-2020 crop period (year). Data Envelopment Analysis(DEA) was applied as an analysis method for efficiency analysis, Quantile Regression(QR) analysis was applied as a factor affecting the efficiency. Results: The reason for the efficiency gap between business entities was that there were many business entities that did not minimize the input cost at the current level of output, and the area where the variance among business entities was large was the fixed cost per 10a. In the results of the affecting factor analysis, it was found that the seed-seedlings cost, fertilizer cost, other material cost, and employment and labor cost had a negative (-) effect on the efficiency, and that the repair and maintenance cost had a positive (+) effect. Conclusion: Therefore, to achieve the efficiency of scale, it is necessary to reduce the input scale to an appropriate level. In the case of business entities with low efficiency by quartile, the seed-seedlings, fertilizer, and other material costs reduce expenditures, and repair maintenance costs can improve efficiency by increasing expenditures.

• Journal of Electrical Engineering and Technology
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• 제9권5호
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• pp.1592-1601
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• 2014

In this study, a novel single phase soft switched power factor correction (PFC) converter is developed with active snubber cell. The active snubber cell provides boost switch both to turn on with zero voltage transition (ZVT) and to turn off with zero current transition (ZCT). As the switching losses in the proposed converter are too low, L and C size can be reduced by increasing the operating frequency. Also, all the semiconductor devices operate with soft switching. There is no additional voltage stress in the boost switch and diode. The proposed converter has a simple structure, low cost and ease of control as well. It has a simple control loop to achieve near unity power factor with the aid of the UC3854. In this study, detailed steady state analysis of the proposed converter is presented and this theoretical analysis is verified by a prototype of 100 kHz and 500 W converter. The measured power factor and efficiency are 0.99 and 97.9% at full load.

• 한국건축시공학회지
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• 제4권4호
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• pp.117-126
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• 2004

Construction industry is faced with the problems such as the quickly changeable circumstance and increasing construction companies due to regulation mollification of company registration. In order to overcome these problems, new estimation system based on historical estimation cost is ready to introduce by government step by step. But the time of transition for estimation system causes another problems such as chaos addition to simultaneity of a standard of estimation system and new estimation system, lack of related regulation, accumulation of historical extensive cost data, and adjustment methodology when historical estimation data is applied to next projects. The purpose of this study is to suggest the change factors by activities for estimating historical cost for apartment housing projects. New estimation system is based on historical construction data. For application of this system, the standard adjustment methodology system is necessary. and extensive cost data should be accumulated under an unified construction work classification system. Therefore in this study, according to the construction work classification system, every apartment housing project was classified to 16 work classifications, and 7 major composed items which occupy more than 85% of construction costs are analyzed by detailed activities and by average ratio and maximum ratio each of them. In the result of the study, furniture work, foundation work and masonry work are the works which have big gap of costs between average ration and maximum ratio. In addition to suggestion of change factor by work species, 5 qualified construction specialists are interviewed and change factors in 7 major works are analyzed.

• 대한간호학회지
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• 제12권1호
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• pp.25-38
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• 1982

As technological civilization and medical science has developed, standards of living have imp-roved and human life expectancy has been extended. But the incidence and mortality rate of cancer have been gradually increasing due to the pollution of the environment. Even though cancer is still a great threat to human beings, the etiology and appropriate cure forcancerhavenotyetbeendiscovered. The early detection and treatment of cancer is urgently needed. This study concentrates on the health behavior of woman regarding the papanicolau smear for early detection of cervical cancer. It was done in order to provide a direction for scientific health education materials by investigating predictors of preventive health behavior. The subjects for this study were made up of 54 woman, who comply with preventive health practices(compliant) who attended the Cervical Cancer Center of Y University Hospital in order to have tests for early detection of cervical cancer and 54 woman who did not comply with preventive health practices (noncompliant) selected from 100 housewives of I apartment, Kang Nam Ku, Seoul. The study method used, was a questionnaire for the compliance group and an interview for the noncompliance group. The period for data collection was from October 13th to October 24th. 1981. Analysis of the data was done using percentages, T-test, Pearson Correlation and Stepwise Multiple Regression. The results of study were as follows: 1. The hypotheses tested were based on the health belief model; 1) The first hypothesis,“The compliant may have more knowledge of the cervical cancer than the noncompliant”was rejected(T=-1.86, p>.05) 2) The second hypothesis,“The compliant may have a higher severity of cervical cancer than the noncompliant”was accepted (T=5.41, p<.001) 3) The third hypothesis, “The compliant may have a higher susceptability to cervical cancer than the noncompliant”was accepted(T=3.51, p<.01). 4) The fourth hypothesis,“The compliant may have more beneHt than cost'from the cervical cancer tests than the noncompliant" was accepted(T=7.46, p<.001). 5) The fifth hypothesis,“The compliant may have more health concern than the noncompliant”. was accepted(T=3.39, p<.01). These results show that severity, susceptability, benefit(over cost) and health concern influence the preventive health behavior in this Study. 2. In the correlation among variables, it was found that the knowledge of cervical cancer and the benefit(over cost) of preventive health behavior were negatively correlated(r=-2.75, p<.01), Severity of cervical cancer and benefit (over cost) of preventive health behavior were positively correlated(r=.280, p＜.01), severity and susceptability of cervical cancer were positively correlated(r= .238, p<.01), benefit(over cost) and health concern were positively correlated(r= .299, p<.01). The benefit(over cost) may be raised by increasing the severity and health concern. Therefore the compliance rate of woman may be raised through health education by increasing the benefit(over cost) of the individual. 3. The Stepwise Multiple Regression between health behavior and predictors. 1) The factor“Benefit(over cost)”could account for preventive health behavior in 34.4％ of the sample(F=55.6204 P<.01). 2) When the factor“Severity”is added to this, it accounts for 44.3% of preventive health behavior(F=41.679, p<.01). 3) When the factor“Susceptability”is also included, it accounts for 46.7% of preventive health behavior(F=30.373, p<.01). 4) When the factor “Health concern”is included, it accounts for 48.1% of preventive health behavior(F=23859, p<.05). This means that other factors appear to influence preventive health behavior, since the combination of variables explains only 48.1％ of the Preventive health behavior. Therefore further study to investigate the predictors of preventive health behavior is necessary.