• 품질경영학회지
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• 제48권3호
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• pp.453-462
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• 2020

Purpose::This study aims to analyze the management performance and production efficiency of medicinal crop farmers. Methods: We conducted an empirical survey of medicinal crop farmers and analyzed production efficiency using DEA method. Results: First, The crops that increased the number of farms during 2010 and 2018 were Angelica tenuissima and Salvia miltiorrhiza, which was attributed to higher income per hour than other crops. Second, As for the efficiency of Liriope platyphylla, the average was 0.376, and the coefficient of variation was the lowest, 0.566. Third, Salvia miltiorrhiza and Atractylodes japonica had the highest technical efficiency after Liriope platyphylla, but the variation coefficient was high and the efficiency was relatively high. Fourth, As a result of performing variance analysis to find out the difference of each crops on the value of medicinal crop efficiency, the technical efficiency, pure technical efficiency, and scale efficiency were all statistically significant. Conclusion: Based on the results above, following policy suggestions are offered. First, It is necessary to provide information on crops with high income compared to the input of labor, and to develop labor-saving cultivation technologies for each crop. Second, A stable labor supply system will be needed in rural areas. Third, Efforts should be made to close the technological gap between farmers through a lot of education and consulting for farmers who grow medicinal crops.

• 한국산업정보학회논문지
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• 제19권3호
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• pp.75-85
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• 2014

This paper is to develop and estimate a closed form inflation model using the estimates for real marginal costs in manufacturing industries during the sample period 1975-2010. The production function in manufacturing industry incorporates labor, capital, domestic material, and foreign material, assuming constant returns to scale technology and AR(1) process of technological coefficient. We derive real marginal costs from firm's cost minimization with quarterly data and provide new evidences on the new Keynesian Phillips curve for Korea. The main empirical result is that the closed form coefficients ${\delta}_1$ and ${\delta}^{-1}_2$ in manufacturing for PPI inflation proved to be 0.5086 and 0.8779 respectively, similar to the estimates in the U.S. case. These results also are consistent with the functional relationship between the coefficients in hybrid model and its closed form. Thus the paper suggests that the empirical studies on inflation dynamics need to focus on the manufacturing industry with market power, treating PPI inflation as the dependent variable.

• 한국지진공학회논문집
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• 제2권3호
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• pp.87-98
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• 1998

In this paper, the potential ground motion in terms of the peak ground accelerations(PGAs) due to long-distance Sumatra earthquakes is investigated for Singapore, following the probabilistic seismic hazard assessment a, pp.oach. The case investigated differs from a conventional one, in that few attenuation equations for long-distance major earthquakes are readily available. The attenuation relationships developed for other regions of the world are thus reviewed. It is found that the existing attenuation equations, when extrapolated to distant major earthquakes, tend to underestimate the PGAs. By comparing with the PGAs recorded over long distances at stations of the Japanese Meteorological Agency for major earthquakes in Japan, an attenuation equation is chosen for this study. With the chosen attenuation equation, the probability of PGAs exceeding selected levels for various exposure periods of time is then computed. The results show that at Singapore there is a 10% probability in 50 years for the PGA at rock sites to exceed 1.1% g. In view of the results and the associated uncertainties, a base shear coefficient of 1.5% is being recommended as the tentative seismic loading in Singapore. The tentative seismic loading reflects the design value of the notional horizontal load, equal to 1.5% of the characteristic building weigh as specified in the BS code, which usualy governs the design of most buildings in Singapors.

• Membrane and Water Treatment
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• 제4권1호
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• pp.1-9
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• 2013

The process of electromembrane transformation of L-lysine monohydrochlorides into their zwitterionic form in four- and two-chamber electrodialysis apparatus was investigated. The process of transformation at various concentrations of lysine monohydrochloride (0.1-0.6 mol.L-1) was studied and it was established that at the optimum density of current optimal concentrations of lysine hydrochloride during electrodyalisis was in the range of 0.2-0.4 mol.L-1. It was determined that the process of total transformation was accomplished when pH of the lysine solution achieved 10. Changes of concentrations of $Cl^-$ ions and lysine diffused into the neighboring chamber were determined depending on the time. The method developed by us allows adjusting the removal coefficient of $Cl^-$ ions during transformation to a maximal value, the losses of lysine diffused into the next chamber after its return to the technological cycle being less than 1.0 %. The specific energy consumption during the process of transformation in two- and four-chamber electrodialyzers was 0.19 and 0.205 A.h.kg-1 and the current efficiency was 75.9 and 73.1 %, correspondingly. Study of the process of electromembrane transformation allowed obtaining zwitterionic form of L-lysine from L-lysine monohydrochloride with minimal reagent and energy consumption.

• 한국정밀공학회지
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• 제26권10호
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• pp.89-96
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• 2009

In recent years, there has been a considerable interest in the application of super plastic forming in the aircraft and automotive industries. This requires a detailed design of the technological process in order to exploit its peculiar potentialities better. Nowadays, the finite element method is used to plan the sheet metal forming processes whose simulation requires determination of material constants for super plastic materials. The present work is aimed to show a simple method to characterize super plastic materials duplex stainless steel which was formed by a constant gaspressure to hemispheres with and without back pressure. The forming operation was performed using an in-house designed and built biaxial forming apparatus. The temporal change of dome heights of hemispheres were measured for applying the pressures. The flow stresses and strain rates developed at the top of the dome during the forming step were shown to follow closely the flow stress - strain rate relationship obtained from the strain rate change tests performed at the same temperature.

• 한국재료학회지
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• 제28권12호
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• pp.748-757
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• 2018

Inorganic semiconductor compounds, e.g., CIGS and CZTS, are promising materials for thin film solar cells because of their high light absorption coefficient and stability. Research on thin film solar cells using this compound has made remarkable progress in the last two decades. Vacuum-based processes, e.g., co-evaporation and sputtering, are well established to obtain high-efficiency CIGS and/or CZTS thin film solar cells with over 20 % of power conversion. However, because the vacuum-based processes need high cost equipment, they pose technological barriers to producing low-cost and large area photovoltaic cells. Recently, non-vacuum based processes, for example the solution/nanoparticle precursor process, the electrodeposition method, or the polymer-capped precursors process, have been intensively studied to reduce capital expenditure. Lately, over 17 % of energy conversion efficiency has been reported by solution precursors methods in CIGS solar cells. This article reviews the status of non-vacuum techniques that are used to fabricate CIGS and CZTS thin films solar cells.

• 드라이브 ㆍ 컨트롤
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• 제21권2호
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• pp.1-7
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• 2024

This paper proposes a novel cooling system for hydrogen fuel cell cooling systems by integrating heat pump technology to enhance operational efficiency. The study analyzed the cooling efficiency of the fuel cell cooling system. With the increasing focus on eco-friendly vehicle technologies to address environmental concerns and global warming, the transportation sector, a major contributor to greenhouse gas emissions, needs technological enhancements for better efficiency. The proposed cooling system was modeled through 1-D simulations. The analysis results of parameters such as thermal balance, temperature, and pressure of each component confirmed the stable operation of the system. By examining variations in the cooling system's flow rate, compressor RPM, and the Coefficient of Performance (COP) based on different refrigerants, initial research was conducted to derive optimal operating conditions and parameter values.

• 한국병원경영학회지
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• 제5권1호
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• pp.232-271
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• 2000

The introduction of a team system to any organization is usually to improve that organizations dynamics, by increasing the proper adaptation to rapidly changing environments, by reducing approval procedures, and by promoting power authorization. In this regard, this study was carried out in an attempt to determine (1) whether or not the introduction of a team system can be as effective in hospital organizations as it has been in business organizations, and (2) what behavior factors influence such effectiveness. For the current study, questionnaires were distributed to the employees of a university hospital in Pusan. Four hundred eighty three of them(94.7%) were retrieved and analyzed through statistical processes. The three types of variables that were found to influence team effectiveness were: (1) independent variables of team organization characteristics, such as communication, organizational atmosphere, leadership and team knowledge, (2) intervening variables of team organization characteristics. such as job autonomy, technological variety, task subjectivity, task feedback and task importance, and(3) the dependent variables of team level effectiveness, such as job satisfaction and commitment to team organization. The gathered data were processed by using the 6.12 version of the statistical program SAS(Statistical Analysis System), and the reliance coefficient of those measured variables was then evaluated as an average of 0.78. The influence of team level effectiveness was analyzed by using multiple regression analysis. These differences in effectiveness were then analyzed on the basis of related mean values, while the differences among demo-sociological characteristics were analyzed by using the dispersion analysis(ANOVA) and the t-test. The results of the study can be summarized by the following. First, regarding the relationship between team organization characteristics and team level effectiveness, all of the factors including communication, organizational atmosphere, leadership and team knowledge were found to have a significant influence on effectiveness. Second, the factors of team job characteristics, such as technological variety, task importance and job autonomy, had significant effects on job satisfaction and organizational commitment among the teams members. Team level effectiveness was generally high, while team job satisfaction was higher the teams organizational commitment. Third, regarding the demo-sociological characteristics, team level effectiveness was found to be higher among those who were older, who had more job experience, and who had a higher position. Comparing the differences among job types, the effectiveness was relatively higher in the fields of nursing and administration/management then in other fields. Further study should be done towards the setting of variables for characteristics of hospital organization, developing suitable methods of measurement, and researching individual level effectiveness.

• 정보화정책
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• 제31권1호
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• pp.3-31
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• 2024

본 연구는 ChatGPT로부터 촉박된 생성형 인공지능에 대해 국내의 특수성을 고려한 대중의 우려를 살펴보고자 하였다. 이를 위해 유튜브에서 102개의 윤리 관련 뉴스 영상에 포함된 댓글을 파이썬 스크래퍼를 개발하여 수집하였으며, 텍스톰을 통해 형태소 분석 및 전처리를 통해 15,735개 댓글을 대상으로 상관토픽모델(CTM)을 통해 분석하였다. 분석 결과, 뉴스 영상에 포함된 댓글의 주요 토픽은 '법적 및 윤리적 고려 사항', '지적 재산권 및 기술', '기술 발전과 인류 미래, 정보 처리에서 인공지능의 잠재력', 'AI에서의 감정 지능 및 윤리적 규제', '인간모방' 등 6개로 확인되었다. 또한 6개의 토픽을 10% 이상의 상관계수 값을 보이는 관계로 구조화한 결과 '법적 및 윤리적 고려 사항', 'ChatGPT의 데이터 생성 관련 이슈(지적 재산권 및 기술, 정보 처리에서의 인공지능의 잠재력, 인간모방', '인류 미래에 대한 두려움(기술 발전과 인류 미래, AI에서의 감정 지능 및 윤리적 규제)' 등 3개로 구조화할 수 있었다. 이를 바탕으로 ChatGPT로 인해 촉발된 생성형 인공지능에 관한 관심과 더불어 다양한 우려가 공존하고 있는 것을 확인하였고, 국내의 역사적 및 사회적 맥락을 반영한 특수성을 가진 우려도 존재하고 있음을 확인하였다. 이러한 결과를 통해 데이터 공정성에 대한 국가 주도의 노력이 필요함을 제안하였다.

• 대한기계학회논문집
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• 제15권6호
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• pp.2048-2061
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• 1991

본 연구에서는 이와 같은 구비조건과 문제점들을 해소하기 위하여 Fig.1과 같 이 볼 엔드 밀링의 절삭성과 경제적 절삭 속도식을 실용식의 형태로 표현하여 절삭조 건의 최적화를 위한 구속조건으로 설정하였고, 이를 자유곡면의 절삭경로 산출과정에 서 구속조건을 만족하면서 부품당의 생산비를 최소로 하는 스핀들속도와 이송속도를 결정하는 데에 적용하였다. 그리고 이는 실험모형에의 적용예를 통해 계산시간과 정 확도 및 절삭효과 등에 있어서 실용화의 가능성을 검토하였다. 이때 절삭력계를 해 석 함에 있어서는 기하학적 절삭 파라미터들에 대해 무차원적으로 정의된 절삭작용 누 적계수(accumulating coefficient)들을 이용하여 절삭력계를 선형화 된 실용식으로 표 현하였으며, 절삭 상수들과 절삭작용 누적계수들의 선형적 표현에 의해 평균 절삭력계 를 계산한 후, 토크 패턴 모델에 의해 절삭력 집중비를 구함으로써 실 절삭계의 주변 력(peripheral force), 드러스트, 토크, 동력 등을 예측하였다. 또한 절삭속도의 결 정에 있어서는 경제적 절삭속도 예측모델을 설정하여 가공비를 최소로 하는 절삭속도 를 선정토록 하였다.