• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1993년도 Fifth International Fuzzy Systems Association World Congress 93
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• pp.873-876
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• 1993

A fuzzy controller designed by mini-max-gravity(MMG) method is essentially nonlinear with respect to the controller's input and output relationship, and stability analysis is thus needed to construct a stable control system. This paper deals with a design method of a position-type MMG fuzzy controller stable in a sense of Lyapunov when considered is a single-input-single-output linear, stable plant. We first introduce a method to construct a Laypunov function by using an eigen-value of A matrix of the linear, stable plant dynamics and then we derive an asymtotic stability condition in terms of scale factors for fuzzy state variables and controller gain. The stability condition is found reasonably practical through comparing the theoretical stability region with that obtained from simulations.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.454-457
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• 1997

The purpose of this study is to develop an optimal model, using existing models, that is able to estimate the amount of spatter utilizing artificial neural network in the short circuit transfer mode of gas metal arc (GMA) welding. The amount of spatter generated during welding can become a barometer which represents the process stability of metal transfer in GMA welding, and it depends on some factors which constitute a periodic waveforms of welding current and arc voltage in short circuit GMA welding. So, the 12 factors, which could express the characteristics for the waveforms, and the amount of spatter are used as input and output variables of the neural network, respectively. Two neural network models to estimate the amount of spatter are proposed: A neural network model, where arc extinction is not considered, and a combined neural network model where it is considered. In order to reduce the calculation time it take to produce an output, the input vector and hidden layers for each model are optimized using the correlation coefficients between each factor and the amount of spattcr. The est~mation performance of each optimized model to the amount of spatter IS assessed and compared to the est~mation performance of the model proposed by Kang. Also, through the evaluation for the estimation performance of each optimized model, it is shown that the combined neural network model can almost perfectly predict the amount of spatter.

• 대한산업공학회지
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• 제41권5호
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• pp.425-438
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• 2015

This study proposes a three-stage model of R&BD performance which captures commercialization outcomes as well as conventional R&D performance. The model is composed of three factors : inputs (R&D budgets and researchers), outputs (patents and papers), and outcomes (technical fees, products sales, and cost savings). Three stages are defined for each transformation process between the three factors : efficiency stage from input to output (stage 1), effectiveness stage from output to outcome (stage 2), and productivity stage from input to outcome (stage 3). The performance of each stage is measured by data envelopment analysis (DEA). DEA is a non-parametric efficiency measurement technique that has widely been used in R&D performance measurement. We measure the performance of 171 projects of 6 public R&BD programs managed by Seoul Business Agency using the proposed three-stage model. In order to provide a balanced and holistic view of R&BD performance, the R&BD performance map is also constructed based on performance of efficiency and productivity stages.

• 한국의학물리학회지:의학물리
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• 제15권4호
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• pp.237-246
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• 2004

국제방사선량 및 측정위원회(ICRU)가 쐐기인수를 정의하고 있지만 방사선치료계획장치는 쐐기에 관한 다른 개념을 도입하여 선량을 보정하기도 한다. 개념이 다른 인수들은 아주 다르게 정의되어 있기 때문에 그 값도 용납될 수 없을 정도로 다를 수 있어서 심각한 선량오차가 발생될 수 있다. 설치된 방사선치료기(Cinac 21EX, Varian, 미국)에는 물질쐐기(위와 아래)와 위턱에 의한 쐐기 기능이 있고 방사선치료계획장치(RTPS)로 Eclipse(Varian, 미국)와 Pinnacle$^{3}$(ADAC, 미국)가 사용되고 있다. 물질쐐기와 기능상쐐기의 쐐기인수, 쐐기상대출력인수 및 쐐기출력인수를 물팬톰에서 이온함으로 측정하여 조사면크기와 쐐기위치, 쐐기각, X선 투과력, 측정조건에 따라 분석하고 비교하였다. 기능상쐐기가 물질쐐기에 비해 여러 가지 요인에 크게 영향을 받으며, 기능상쐐기의 쐐기인수 등에 영향을 미치는 주된 요인은 조사면크기와 쐐기각 이었다. X선 투과력도 쐐기인수 등에 약간의 영향을 미쳤다. 쐐기에 관련된 상이한 개념의 인수는 그 값이 6 MV는 63%, 15 MV는 59% 이상 다를 수 있기 때문에 선량오차를 줄이기 위해 방사선치료계획장치에 활용되는 인수를 파악하고 RTPS에 합당한 값을 입력해야 한다.

• 보건행정학회지
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• 제6권1호
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• pp.29-58
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• 1996

This study was conducted to identify the factors that affect the output of health conters. An analystical model employed in this study was developed by modifying 'input-output model' and 'organizational behavior model'. Data were collected form two source; the 1995 report of thealth center which was submitted to the Ministry of Health and Welfare and a mail survey questionary of officers at health center, including 66 directors and 1,768 staffs of the health centers in southern region. The major findings are as follows: That analysis has identified the factors associated with dependent variables: medical services provided by the health center and health program performance(HPP). The number of primary medical facilities was negatively associated with health center performance while the number of staffs, job satisfaction, and professional background of health center directors were positively associated. These independent variables accounted for 40.1% of the variance of dependent variables. The variance of HPP was significantly explained by the number of health subcenter and primary health post, priority level of public health program by hief executive officers(CEOs) and legislator. A significant relationship was found between leadership types of health center directors and the performance of maternal and child health program. Considering these results, the authors suggested that the role in medical care service of health center in the should be rearranged at local level because medical care service of the health center is competing with primary medical facilities in the same region. It is also suggested that educational efforts be made to improve leadership of the health center directors and concern with public health program by the CEOs and legislators of local governments.

• 산업기술연구
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• 제15권
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• pp.195-202
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• 1995

In this paper, we analyze the effects of scaling factors on the performance of a fuzzy controller. The quantitative relation between input and output variables of a fuzzy controller is obtained by using a quasi-linear fuzzy model. And an approximate transfer function of a fuzzy controller is derived from the comparison of fuzzy controller with the conventional PID controller. Then we analyze the effects of scaling factor using this approximate transfer function and root locus method.

• 에너지공학
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• 제21권2호
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• pp.158-167
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• 2012

본 연구의 목적은 투입산출 구조분해분석을 통해 도시가스산업의 성장요인을 분석하는 것이다. 산업연관표에 기초한 Syrquin의 분석모형을 활용하여 1995-2000-2005-2009 기간 동안 우리나라 도시가스산업의 성장요인을 분석하였다. 기간별 산출액 변동요인을 (a)국내 최종수요 증가 효과 (b)수출증가 효과 (c)최종재 수입대체 효과 (d)중간재 수입대체 효과 (e)기술변화 효과 등 5개로 분해하였다. 분석결과, 1995-2009 기간동안 성장기여율이 가장 큰 요인은 (a)국내 최종수요 증가효과(48.4%)와 (e)기술변화 효과(38.6%)인 것으로 나타났다. 1995-2000, 2000-2005, 2005-2009 세 기간별 분석결과, (a)국내 최종수요 증가효과는 점차 감소($84.5%{\rightarrow}18.9%{\rightarrow}15.4%$)하고 있었고, (e)기술변화효과는 상승($7.4%{\rightarrow}70.0%{\rightarrow}42.2%$)하는 양상을 보이고 있었다. 최종수요 기여율의 변화 이유는 1980년대 도시가스 보급이 시작되면서 민간분야의 수요가 지속적으로 확대되다가 1998년 외환위기 이후 성장세의 둔화 및 수요포화 현상과 관련이 있고, 기술변화 기여율 변화 이유는 산업 활동에 있어서 에너지 수급방식이 석탄, 석유 등 전통적인 방식에서 천연가스 등 친환경적 에너지를 사용하는 방식으로 바뀌어 가고 있는 양상을 반영한다고 볼 수 있다. 분석결과 도시가스산업의 성장견인 요인의 중심이 국내 최종수요확대에서 기술변화로 옮겨 가고 있으므로, 친환경적 도시가스산업의 지속적인 성장을 위해서는 주거 주택용보다 산업 활동에서의 도시가스 인프라 확대를 고려할 필요가 있다는 정책적 함의를 지닐 수 있다.

• 한국병원경영학회지
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• 제10권1호
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• pp.71-92
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• 2005

The purpose of this study is to analyze the efficiency in management of general hospitals and investigate the major factors on efficiency. Specifically, the management of each general hospital is evaluated by using Data Envelopment Analysis(DEA) technique which is a nonparametric statistical method for measurement of efficiency. Then, the influencing factors are investigated through analyses of Decision-Tree Model and Tobit Regression. The target hospitals were general hospitals in which bed sizes are between 200 and 500 among a total of 276 general hospitals. The main data of financial indicators were collected from 48 hospitals, and it was analyzed by using two statistical models. For Model I, three input and two output variables were used for efficiency evaluation. In particular, three input variables were the number of medical doctors, the number of paramedical personnel, and the bed size. And, two output variables were the numbers of inpatients and outpatients per year, adjusted by bed-size. The results of DEA analysis showed that only seven out of 48 hospitals(15%) turned out to be efficient. The decision-tree analysis also showed that there were six significant influencing factors for Model I. Six factors for Model I were Bed Occupancy Rate, Cost per Adjusted Inpatient, New Visit Ratio of Outpatients, Retired Ratio, Net Profit to Gross Revenues, Net Profit to Total Assets. In addition, the management efficiency of hospital is proved to increase as profit and patient-induced indicators increase and cost-related indicators decrease, by the Tobit regression model of independent variables derived from the decision-tree analysis. This study may be contributable to the development of analytic methodology regarding the efficiency of hospital management in that it suggests the synthetic measures by utilizing DEA model instead of suggesting simple ratio-analyzing results.

• 산업경영시스템학회지
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• 제46권4호
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• pp.39-52
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• 2023

In this study, project information of government-funded research institute in the food field was collected and analyzed to systematically identify the factors affecting the process of transferring technological achievements of public research institute to the private sector. This study hypothesized that human resources, financial resources, and technological characteristics as input factors of R&D projects affect output factors, such as research papers or patents produced by R&D projects. Moreover, these outputs would serve as drivers of the technology transfer as one of the R&D outcomes. Linear Regression Analysis and Poisson Regression Analysis were conducted to empirically and sequentially investigate the relationship between input factors and output and outcome of R&D projects and the results are as follows: First, the principle investigator's career and participating researcher's size as human resource factors have an influence on both the number of SCI (science citation index) papers and patent registration. Second, the research duration and research expenses for the current year have an influence on the number of SCI papers and patent registrations, which are the main outputs of R&D projects. Third, the technology life cycle affects the number of SCI papers and patent registrations. Lastly, the higher the number of SCI papers and patent registrations, the more it affected the number of technology transfers and the amount of technology transfer contract.

• 한국세라믹학회지
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• 제43권9호
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• pp.519-526
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• 2006

A full-factorial design of experiments with three input factors and two levels for each factor including center points was utilized for the preparation and characterization of twelve types of $BaTiO_3$ slips for tape casting. Ceramic powders with different particle sizes, different milling methods such as high energy milling and conventional ball milling, and two types of dispersant with different polymeric species were chosen as input factors in order to investigate their effects on slip and on green tape properties. Tape casting, a small rectangular-shaped K-square preparation, characterization and quantitative data analysis using statistical software were followed. Ceramic powder was the most significant among three input factors for the output responses of slip viscosity and green tape density, showing more favorable results with large particles than with very fine ones. In addition, high energy milling for only 30 min was more efficient than 24h of conventional ball milling in terms of powder dispersion and milling. The optimum condition based on the experimental results was a slip exposed to high energy milling with large ceramic particles along with a methylethyl acetate dispersant.