• 대한치과기공학회지
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• 제10권1호
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• pp.25-41
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• 1988

In order to provide the National Dental Health Program with dasic data, and to implove the laborartory managent style, the author studied the operational situations of dental lads through questionaire. The results are as follows, 1. Unlicensured personnel should be replaced by the licensured(from present rate lf 49.2% licensured to more than80%) 2. Minimum wage guarantee system as well as well as oage raise should be established. 3. Monthly balancing accounts system and bepreciation reserve accounts system should be established for the reasonable management. 4. Manufacturing period should be elongated from presnt 2.8 days to 5-7 days for quality betterment of the processes. 5. Medical insurance system should be applied to the dental processes. 6. Manufacturing cost should be increased by 35%. 7. Retirement grants lr retirement annuity system, improvement of occupational environ-ment, and holidays incentives, and participation in medical insurance system should be adopted for the wellfare of the dental technicians. 8. Laboratory managers should operate the lads with pride and valuation. 9. Business Management course should be included in the curriculum of the dental labo-ratory school. 10. Good relationship between Korean Association of Dental Laboratory Technicians and local laboratories shorld be improved.

• 품질경영학회지
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• 제29권3호
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• pp.1-17
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• 2001

Among the activities of industrial companies, manufacturing processes are major sources of environmental problems. So, many companies with manufacturing processes have taken the necessary actions to comply with environmental regulations. But, most of them have mainly focused on the 'end-of-pipe techniques' to reduce pollutants in a short period of time. However, these reactive approaches are basically symptomatic treatments and no more appropriate for sustainable development and growth. The cleaner production, which deals with pollutants at the place of origin, has been introduced as a solution to the problem. In this paper, an operational model of cleaner production system Is proposed and the factors, which affect tile performance of cleaner production, are identified through the field survey of 37 manufacturing companies.

• 한국농공학회논문집
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• 제54권6호
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• pp.39-44
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• 2012

Water supply capacity and operational capability in agricultural reservoirs are expressed differently in the limited storage due to seasonal and local variation of precipitation. Since agricultural water supply and demand basically assumes the uncertainty of hydrological phenomena, it is necessary to improve probabilistic approach for potential risk assessment of water supply capacity in reservoir for enhanced operational storage management. Here, it was introduced the irrigation vulnerability characteristic curves to represent the water supply capacity corresponding to probability distribution of the water demand from the paddy field and water supply in agricultural reservoir. Irrigation vulnerability probability was formulated using reliability analysis method based on water supply and demand probability distribution. The lower duration of irrigation vulnerability probability defined as the time period requiring intensive water management, and it will be considered to assessment tools as a risk mitigated water supply planning in decision making with a limited reservoir storage.

• 산업경영시스템학회지
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• 제24권69호
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• pp.1-12
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• 2001

In this paper, the consumable concurred spare parts requirement determination problem of newly procured equipment systems is considered. The problem is formulated as the operational availability maximization problem with any given fund limitation. the that the failure of a part follows a Poisson process and part failure rate is constant in spite of the decrease of number of equipments during operational period, an analytical method is developed to obtain spare part requirements using the generalized Lagrange multipliers method, The numerical examples show that analytic solution is mostly equal to the realistic solution obtained from simulation regardless of assumptions about part failure rate. It is expected that the analytical method developed in the paper can be effectively used to make a budget for provisioning the concurrent spare parts of newly procured equipment system.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.1-6
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• 2007

A train is subject to a series of reliability-related tasks through its entire life cycle. Among them the reliability demonstration is required for commercial trains and the test is performed during the commissioning period or the early stage of the commercial operation. On the other hands various test are carried out for prototype trains and hence their operational condition is quit different from that of the commercial trains. One should take account of these differences when reliability assessment is needed for the prototype trains. This paper presents a procedure and an analysis method to evaluate reliability of a prototype train. Reliability data have been obtained through test runs of the HSR-350x and operational conditions for the KTX and HSR-350x have been analyzed to compare the reliability targets of the prototype train.

• 한국태양에너지학회 논문집
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• 제27권1호
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• pp.1-9
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• 2007

This paper reveals both the operational situation and the cause of the error occurred in wind turbine generator system of Hangwon wind farm in Jeju island. The four wind turbines were selected for this work, and the monitored period was for six months. Wind resource in the wind farm was analyzed, and the estimated energy production was compared with the actual energy production. As a result, with a decrease of system error, the estimated energy production was in good agreement with the actual energy production. The errors occurring in components such as gearbox and hydraulic motor affected the Availability of the wind turbine. Also, poor external conditions such as a strong wind, lightning and gust caused a standstill of wind turbines.

• 한국시뮬레이션학회논문지
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• 제10권3호
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• pp.83-94
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• 2001

In this paper, the consumable spare parts requirement determination problem of newly procured equipment systems is considered. The problem is formulated as the cost minimization problem with operational availability constraint. Assuming part failure rate is constant during operational period, an analytical method is developed to obtain spare part requirements. Since this solution tends to overestimate the requirements, a fast search simulation procedure is introduced to adjust it to the realistic solution. The analytical solution procedure and the simulation procedure are performed recursively until a near optimal solution is achieved. The experimental results show that the near optimal solution is approached in a fairly short amount of time.

• Journal of Korea Trade
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• 제25권7호
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• pp.19-40
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• 2021

Purpose - This paper's purpose is to investigate how foreign ownership and innovation affect firm value. Design/methodology - Firm innovation is defined as operational efficiency, which is calculated by adopting data envelopment analysis (DEA). Additionally, R&D intensity is included as a measure of innovation in the analysis. We used firm-level data from manufacturing companies in Korea. The sample comprised 3,753 firm-year observations for every year in the period 2003-2017. Findings - We found that foreign ownership and innovation are positively related to firm value (Tobin's Q). Foreign ownership moderates innovation's contribution to firm value, implying that foreign ownership may enhance the value relevance of firm innovation. In addition, we found that firm innovation partially mediates the relationship between foreign ownership and firm value. Originality/value - This highlights the important role of foreign investors' monitoring; wherein foreign investors enhance firm value by facilitating firm innovation. Our results suggest that foreign ownership can be crucial for innovation and may serve to address weak ownership structures.

• Journal of Electrical Engineering and Technology
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• 제8권5호
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• pp.1107-1115
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• 2013

A new PWM technique for a two-phase BLDC motor fed by a two-phase eight-switch inverter is proposed in this paper. It is well known that a two-phase eight-switch inverter can significantly improve power output compared with a two-phase six-switch inverter in a two-phase motor drive. To drive the two-phase BLDC motor simply and effectively, two normal PWM strategies are investigated to manage speed regulation. However, under the conditions of low speed and light load, especially during the braking process, the current in a short time of one period is near zero, which is a discontinuous waveform every half period. To solve it, a novel PWM technique is investigated to improve the operational performance of normal technique. Using the new PWM scheme, the current continues every half period and the braking performance is improved. The effectiveness of the proposed PWM method is verified through the experiments.

• 한국초등과학교육학회지:초등과학교육
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• 제31권4호
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• pp.513-531
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• 2012

This study was to analyze the characteristic of scientific argumentation in the classes for the gifted of elementary school. The participants of this study were 5 fifth graders and 9 sixth graders, 14 in total, from the basic unit schools for gifted students of J elementary school in Incheon city. And it constituted small scale groups made up of 2~3 students with similar or identical ability in scientific reasoning. It had set up hypothesis for each group before the experiment, and students had a group discussion as a whole after the experiment. Classes were conducted 4 times, all courses were recorded as a sound/video. The ability in scientific reasoning of the students was inspected, making use of SRT II by means of pre-survey, and their argumentation levels were analyzed, utilizing 'Rubric for scientific argumentation course assessment.' As a result, argumentations did not incurred in every class. Analysis in argumentations of the students resulted in low level argumentation. This means argumentation cannot incur based on that with the limit in understanding the principle of experiments over the threshold of textbook no matter that he is an gifted student or not. The student both in formal operational period and transition period (2B/3A), the ability of scientific thinking in upper level, was improved of his argumentative ability in an overall aspect. However, a student of concrete operational period, the ability of scientific thinking in lower level, had argumentation with still lower level even after the experiment at the moment of discussing with the students on the upper level of scientific thinking ability.