• 한국산업융합학회 논문집
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• 제25권6_2호
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• pp.1071-1081
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• 2022

As the demand for high-rise buildings increases, the demand for high-speed elevators is also increasing. In order to make a high-speed elevator, a method is needed to reduce the weight of the elevator's components, which is a constraint on the increase in speed. As a measure to reduce the weight, it is possible to remove the traveling cable for power and signal supply. Since the weight of the traveling cable varies depending on the position of the carriage, it is difficult to compensate the weight using the counter weight. The power supply is a structure in which a brush-rail type power input terminal is installed in the elevator hoistway to receive power in a contact-type manner while the carriage is moving. If a small-capacity ESS is installed in a passenger car, power can be supplied uninterruptedly inside the passenger car. A small-capacity ESS charging system to be applied to such an elevator system is required to perform several functions. First, the passenger Car must be able to charge as much as possible even during high-speed operation. A control algorithm with high responsiveness is required because charging starts and ends repeatedly by the partially installed input power stage. In addition, if the input-side line impedance is large due to the structure of the system and the response characteristic is increased, the stability of the system may be lowered. Accordingly, in this paper, we propose a control algorithm that has a stable steady-state output while having a fast response in a transient state. To verify the proposed control algorithm, simulation was conducted using PSIM, and the performance of the controller was verified by manufacturing a prototype buck conveter charger.

• 의학교육논단
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• 제25권1호
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• pp.45-54
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• 2023

We investigated the work-life balance of clinical professors in charge of patient care, research, and education at medical schools and the demand for work-life balance support according to position (professor, associate professor, or assistant professor). In total, 163 clinical professors completed the consent form and participated in the study. They filled out an online survey consisting of questions about essential characteristics, a work-life balance test, stress, burnout, work-life satisfaction, and work-life balance support needs. We analyzed the results by analysis of variance and cross-tabulation using IBM SPSS ver. 23.0. Differences were found in work-life balance, stress, burnout, and satisfaction with life and work by position. The requirements for support for work-life balance also varied by professional status. Professors had a higher balance between life and work than associate professors or assistant professors. The specific requirements for work-life balance support were also slightly different for each position. Overall, there was a high demand for work process simplification and efficiency for work support, flexible working hours and sabbatical years for family and leisure, and career management consulting and training support for growth. Assistant professors and associate professors had a lower level of work-life balance than professors, as well as higher levels of stress and burnout. Professors' job satisfaction was also higher than that of the other groups. Based on the results of this study, we hope that a healthy work environment can be established through work-life balance support suitable for clinical professors' positions.

• 한국표면공학회지
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• 제46권6호
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• pp.271-276
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• 2013

The demand for stainless steel is continuously increasing with the development in offshore industry due to its excellent corrosion resistance characteristics. However, it suffers cavitation-erosion in application of high rotating fluid and the damage accelerates in combination with electrochemical corrosion because of Cl-ion in sea water. This paper investigated the complex damage behavior for 431 stainless steel, that is one of martensite stainless steels, through the hybrid test in sea water. Various experiments were carried out, including potential measurement, anodic/cathodic polarization experiment and Tafel analysis. Surface morphology was observed and damage depth was analyzed by SEM and 3D microscope after each experiment, respectively. The results revealed that more active potential was observed under cavitation condition than static condition due to breakdown of passive film and activation of charge transfer, and that higher corrosion current density was obtained under cavitation condition due to synergistic effect of corrosion and erosion.

• 대한기계학회논문집B
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• 제27권10호
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• pp.1427-1434
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• 2003

Turbo- or Super-charging has been used to boost engine power for Gasoline- and Diesel Engine since beginning of 20th century. So far turbo-charger has enjoyed a high reputation in the charging field for its technical advantages such as no demand of operation power from engine and an excellent charging effect in a static operation at mid- and high engine speed. A mechanically driven super-charger, however, is now popular due to the high engine power at quick change of the driving mode - high engine torque even at low engine speed. Since super-charger needs operation power from engine, it is difficult to improve its relatively higher fuel consumption than that of turbo-charger. This negative point is still an obstacle to the wide use of supercharger. Super-charger using screw-type compressor will fulfill the purpose to reduce fuel consumption by minimizing operation power owing to no charge at idling or part load driving condition. This study aims to develop power control concept to achieve the minimization of operation power. A screw type super-charger was modified in design partially and installed with an internal bypass valve and a bypass tube to control charging pressure at part load. The various control concepts show a possibility to reduce operation power of super-charger.

• 수산경영론집
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• 제24권1호
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• pp.29-44
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• 1993

The Purpose of this study is to consolidate the management status of Saggoson in the Choson period by literature research, and examined latest status by field investigation. During the Choson period, there were fish distributors such as Saggoson and Kakju. Saggoson took charge of fish distribution from the fishing ground to the land, and handed over the fish to Kakju who sold over them to the whole country: This distibution system of fish was started from and adapted to the yellow-corvenia fishery of Westhern Sea. There were two resons far this. One was that these fish were. caught much from vast fishing grounds and had a very strong demand, for which professional disributors were needed. The thor was that because fishermen had very limited capital, they had to supply the money for fish production from capitalists like Kakju whom they agreed to sell fish directly to. By this time, it was thought that the fish distibution system for the Westhern Sea fishery was determined by the background and tradition. Meanwile, Saggoson, which has been working far a long time in Westhern Sea, is placed in changing circumstances. That is, small scale fishery Saggoson deals with will be getting fewer, because the big scale reclamation projects in this area threatens the fishery's existence. Also, Saggoson, presently, might be forced to become more efficient in its distribution in the future. In this situation, the management status of a Sggoson in the past and present needs to be consolidated and investigated through this study.

• 정보보호학회논문지
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• 제28권3호
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• pp.655-663
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• 2018

디지털화가 가속되면서 학교나 도서관 등 공공기관에서 디지털 정보의 이용이 증가하고 있으며 프린트 서비스의 요구도 점점 증가하고 있다. 많은 서비스 가운데 공공 PC에서 프린트 서비스를 이용할 시 사용료를 지불하도록 해야 하는데 관리자에게는 꽤나 까다로운 업무이다. 이러한 까다로운 업무를 자동화할 수 있도록 하는 프린트 관리 시스템이 개발되어 현재 널리 사용되고 있다. 이 논문에서는 현재 공공기관의 공공PC에서 사용되고 있는 프린터 관리 시스템의 취약성을 분석하였는데 공공 PC 관리자 및 프린터 관리 솔루션 개발자들의 보안의식과 보안개발에 대한 인식은 아직 많은 부분이 부족한 것으로 보인다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2002년도 학술논문발표회
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• pp.109-113
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• 2002

Urban public service is goods and activities which satisfy public demands for the political, social, economic, cultural activity and household affairs of individual or groups and which urban government supply with free of charge. In view of government, in addition to fairness of facilities location, location of such facilities are to be determined the respect to cost of locating facilities and developmental direction in the future. Therefore, it is necessary to study on feasibility. A feasibility study Is an effective tool in determining the decision of investment or not and the level of investment priority on Projects requiring a sizeable investment and the feasibility of a project. The first, it is to select reasonable location. It was selected four and two by consideration of facilities distribution and connection with others. Six proposal selected was estimated by five element of approach, demand, symbol, reality, environment. In result proposal I was chosen. The next, it is to estimate scales. The finally, it is to study on economical efficiency. Net Present Value was came out ￦4.4billion by 20years and Inter Rate of Return showed up 11%. in addition, it offer various benefit by public facilities. In conclusion, this project is reasonable.

• 한국자동차공학회논문집
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• 제11권6호
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• pp.21-29
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• 2003

Boosting of engine power by using Turbo- or Super-charger is a solution to comply with $CO_2$-regulation in Europe. Turbo-charger is now playing a major role in the field of charging system thank to its technical advantages such as no demand of operation power from engine. A mechanically driven Super-charger, however, is now popular due to quick speed response to change of the driving mode-high engine torque even at low engine speed. Since Super-charger needs operation power from engine, it is difficult to improve its relatively higher fuel consumption than that of Turbo-charger. This negative point is still an obstacle to the wide use of Super-charger. This study aims to develop power control concept to achieve the minimization of operation power when it is not necessary to charge at idling or part load driving condition. A screw type Super-charger was modified in design partially and adapted an internal bypass valve and a bypass tube to control charging pressure at part load. The various control concepts show a possibility to reduce operation power of Super-charger and result in improvement of fuel consumption.

• 한국관광식음료학회지:관광식음료경영연구
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• 제9권
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• pp.213-242
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• 1998

Even in the best of economic environments, restaurants menu pricing is a serious concern to those in the food service industry. During times of rapid inflation, closer government regulation of compensation practices, and limited gains in worker productivity, the decisions regarding the proper charge for menu items become increasingly important. In addition to many operational and managerial factors, an important ingredient in the food service enterprise's success is its ability to meet the market by providing the value expected. The contribution-margin approach to pricing described above is familiar to cost accountants, who will also recognize that it admits of much elaboration before it can become a tool for day-to-day decisions. But the system probably has the greatest promise for multi-unit companies, where the cost benefit ratio of additional refinements improves in proportion to the number of operations. For example, the analysis required to specify the demand function better becomes less expensive if the findings can be applied to the pricing structure of numerous units. In any of its many adaptations, the essence of the integrated menu pricing system remains its ability to bring together the relevant revenues and costs with the operator's sense of the market and competitive environment to suggest prices that maximize profits.

• 에너지공학
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• 제24권3호
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• pp.74-81
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• 2015

늘어나는 전력 수요와 탄소배출을 줄이기 위하여 정부는 신재생에너지 및 에너지저장장치 도입을 장려하고 있다. 정부 는 2020년까지 ESS 누적용량을 2GW로 확대할 예정이다. ESS 도입을 통하여 전력 피크를 줄일 수 있으며, 시간대별 차등요금제를 활용하여 남는 전력을 판매할 수 있다. 본 논문에서는 ESS 보급 확대에 따른 비용을 분석을 위한 모형을 제안하였으며, 2035년까지의 ESS 발전량과 발전단가를 분석하였다. 또한 ESS와 신재생에너지 연계에 따른 경제성 분석을 위하여 태양광발전 및 풍력발전 연계에 따른 사례연구를 진행하였고, ESS 보급 촉진을 위하여 정부의 추가적인 보급지원 정책이 필요함을 시사하고 있다.