• Proceedings of the Safety Management and Science Conference
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• 1999.11a
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• pp.109-121
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• 1999

플랜트 및 설비가 대규모, 정교화, 복잡화 될수록 이로 인한 고장 및 오류에 의한 피해가 막대하기 때문에, 시스템의 신뢰성, 보전성 및 안전성 향상과 제품 품질 향상을 추구 및 안전성 유지에 대한 관심이 고조되고 있다. 고장진단은 잠재적으로 노이즈를 가지고 있다고 생각되는 데이터의 해석에 근거하여 시스템의 고장을 찾는 일련의 체계적이고 통합된 방법이다. 그러나 대부분의 방법들이 이진 논리에 기초를 둔 추론으로 불확실성을 제대로 결과에 반영하지 못하고 있다. 본 논문에서는 예방정비의 관점에서 시스템에 내재된 다양한 불확실성을 효율적으로 처리하기 위해 전문가의 직관과 경험등을 기초로 하여 언어학적 변량을 취하고, 이를 퍼지 기법을 이용하여 정량화 함으로써 불확실성을 고려한 판단이 가능하게 하는 퍼지 전문가 시스템을 제안한다.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.46
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• pp.229-240
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• 1998

In these days, we are facing the needs of the times that the product have to be converted from quantity to quality. Most companys now pay more attention to maximize efficiency of facilities with introducing high priced equipments, those equipments are too automated and electronic that partial failure or short time stop leads to the stop of producing process in the whole factory. Consequently, effective maintenance management of production equipment becomes a only solution against problems. This thesis develops a preventive maintenance software that grasp a failure sign through daily inspection with management item, Machine-Capability index and estimate a trend, determine the time of preventive maintenance. The software is useful to the plant operator in analyzing information easily and controlling preventive maintenance operations efficiently.

• 전기의세계
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• v.36 no.6
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• pp.411-420
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• 1987

환경오염 문제가 심각한 오늘날 사람들은 대기, 수질 등에 대해서는 오염의 형태를 쉽게 인식하나, 전자오염(Electromagnetic-Pollution)에 대하여는 직접적으로 느낄 수 없는 까닭에 잘 이해하지 못하고 있는 실정이다. 그러나 이 전자오염은 개개인 뿐만 아니라 많은 사람들에게 영향을 미칠 수가 있다. 예를 들어 뇌방전에 의한 전기적 과도현상으로 항공 관제탑과 비행기들과의 통신이 두절되어 충돌사고를 일으킬 수 있기 때문이다. 이러한 전자잡음현상을 EMI(Electromagnetic Interference)라고 하는데 요즈음은 부품의 고속화, 고집적화로 인해 전기.전자제품의 내잡음성이 감소될 뿐 아니라 저가격화 및 정보사회 발달에 따른 기기의 급속한 보급으로 전자환경보전이라는 면에서 EMI현상은 매우 심각한 실정이다. 또한 전기.전자에서의 EMI연구 뿐 아니라, 전력의 질적향상을 위하여 고주파, 유도장해 등의 전력계통에서의 EMI현상도 검토되어야 한다. 저주파대에서의 전력계통 EMI현상은 송전선 인근의 통신선 안전문제, 라디오, TV의 수신장해문제, 차기 초고압(800KV급), 송전선 설계문제 등을 감안할 때, 매우 중요한 분야라 하겠다. 여기에 부품 또는 설비가 외부잡음이나 내부잡음에 영향을 받지 않고 또한 그 기기 자신이 방출하는 잡음이 다른 곳에 영향을 주지 않는 양위성 즉 EMC (Electromagnetic Compatibility) 제어가 필요하게 되었다.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.11
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• pp.82-90
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• 1995

This paper pressents a condition-based maintenance (CBM) method through bibration analysis. The well known frequency analysis is employed for performing machine fault diagnosis. The statistical control chart is also applied for analyzing the trend of the bearing wear. Vibration sensors are attached to prototype machine and signals are continuously monitored. The sampled data are utilized to evaluate how well the fast fourier transform(FFT) and the statistical control chart techniques could be used to identify defects of machine and to analyze the machine degradation. Experimental results show that the propowed approach could classify every mal-function and could be utilized for real machine diagnosis system.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.969-974
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• 2005

TPM program, which is a methodology for improving the management results through the management innovation activity of a company, has been widely introduced in the field of a service industry as well as a manufacturing industry. The main purpose of this study is to present the theoretical model by the relationship between active factors of TPM program and management results for a productivity increase, and to investigate the direct and indirect effects on the management of a company through a parametric study. A questionnaire survey of 300 companies that presently utilize the TPM program has been conducted. In order to verify the validity and the reliability of the contents of the questionnaire survey, a confirmatory factor analysis has been done. A frequency analysis has also been performed to examine the characteristics of the respondent. The factor analysis and the frequency analysis were done by using SAS Ver. 8.2, and the verification of a research model was done by using LISREL Ver. 8.52. The active factors of TPM in the research model consist of 'an independent preservation', 'an individual improvement', 'a planned reservation' and 'an education & training'. Among those active factors, the individual improvement and the education & training significantly influence on the facility efficiency and the organization and personnel management. The organization and personnel management has a greater influence on the management results. Therefore, the education and training for employes is most important for the improvement of the management results through TPM program, and the individual improvement activity is also important.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.1
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• pp.33-39
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• 2007

LonWorks over IP (LonWorks/IP) virtual device network (VDN) is an integrated form of LonWorks device network and IP data network. LonWorks/IP VDN can offer ubiquitous access to the information on the factory floor and make it possible for the predictive and preventive maintenance on the factory floor. Timely response is inevitable for predictive and preventive maintenance on the factory floor under the real-time distributed control. The network induced uncertain time delay deteriorates the performance and stability of the real-time distributed control system on LonWorks/IP virtual device network. Therefore, in order to guarantee the stability and to improve the performance of the networked distributed control system the time-varying uncertain time delay needs to be compensated for. In this paper, under the real-time distributed control on LonWorks/IP VDN with uncertain time delay, a control scheme based on disturbance observer and ZPETC(Zero Phase Error Tracking Controller) phase lag compensator is proposed and tested through computer simulation. The result of the proposed control is compared with that of internal model controller (IMC) based on Smith predictor and disturbance observer. It is shown that the proposed control scheme is disturbance and noise tolerant and can significantly improve the stability and the tracking performance of the periodic reference. Therefore, the proposed control scheme is well suited for the distributed servo control for predictive maintenance on LonWorks/IP-based virtual device network with time-varying delay.

• The Journal of Korean Institute for Practical Engineering Education
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• v.1 no.1
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• pp.19-24
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• 2009

It is necessary that the industry has to develop various automated control technology for efficient creation of manufacture automation system according to rapid market situation. One of the technologies is the fused complex control based on PLC-based controlled system. According to rapid growth and distribution of various automated control technologies using PLC, the engineers in automation, Production and manufacturing technologies fields have difficulties in systematic studying on the technologies by choosing an optimal route due to various industry-applied examples and ranges, in spite that the technology is essential. Therefore, the researchers indicate applied outputs and effects extracted by systematically developing systematic company-specified training program by analyzing education procedure drawbacks for S-company engineers.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.1
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• pp.18-26
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• 2009

Recently, from an environmental conservative point of view, the need of high-efficiency lighting system, using LED(Light Emitting Diode) light sources have been increased. However, applied LED light sources without regard to its color and pattern provide visual discomfort to occupant. The objective of this study is not only to evaluate the performance of task work under different correlated color temperature condition, but also furnish the preliminary data as concerning its purpose and user of inner space. For the purpose of this study, two types of LED light sources and a fluorescent light source were selected. Thirty undergraduate students served as the participants. Two different task work sheets were conducted to evaluate the accuracy and duration of time. Results from subjective performance, task work of error modification showed that LED light sources were 2.5[%] higher in accuracy with 17.1[%] lower duration than a fluorescent light source. In the case of reading task work, It is presented 20.6[%] decrease with the LED light sources comparison with a fluorescent light source.

• The Optical Journal
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• s.167
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• pp.19-23
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• 2017

최근 국내 실물경기는 수출 부진이 지속되는 가운데 건설투자 중심으로 내수가 완만하게 증가하는 추이를 보이고 있다. 내수는 설비투자가 부진한 반면 건설투자가 높은 증가세를 보이면서 전체 성장을 주도하고 있고, 민간소비는 완만한 증가세를 지속하고 있다. 수출은 전년에 이어 감소세가 지속 중이나, 금년들어 감소폭이 줄어들고 있다. 전체적으로 수출 부진에 따른 성장 둔화를 건설투자가 보전하는 구조로, 경제성장의 건설투자 의존이 심화되는 특징을 보이고 있다. 2017년 세계경제는 완만한 회복세가 이어지면서 전년보다 소폭 높은 성장을 보일 것으로 예상된다. 선진권의 경우 비교적 꾸준하고 완만한 성장세가 이어질 것이나, 중국은 완만한 성장 둔화 추이가 이어질 전망이다. 유가는 세계경제의 소폭 개선과 OPEC의 감산 합의 등으로 2017년 중 평균 배럴당 50달러 내외로 높아질 전망이며, 원/달러 환율은 연중 비교적 높은 변동성을 보이겠지만, 연평균 기준으로 전년과 비슷한 수준(1,150원대)이 예상된다. 2017년 국내경제는 수출 부진이 다소 완화되겠지만, 2016년 경제성장을 견인해 온 건설투자 증가세가 크게 둔화되고 구조조정 등이 민간소비 증가를 제약하면서 전년보다 약간 낮은 2.5% 내외 성장을 보일 것으로 예상된다. 전기비로는 상${\cdot}$하반기 비슷한 성장이 예상되지만, 전년 패턴의 기저효과로 전년동기비 성장률은 소폭의 上低下高 흐름이 예상된다. 대외적으로는 미국 신정부의 정책 기조와 연준의 금리인상, 중국의 성장 둔화 폭 확대 가능성 등이, 국내적으로는 가계부채 문제와 구조조정 여파 등이 주요 변수로 작용할 전망이다. 부문별로 살펴보면 민간소비는 유가 반등에 따른 소득 증가세 둔화, 가계부채 부담, 구조조정 여파 등이 제약요인으로 작용하면서 전년보다 소폭 낮은 연간 2% 내외의 증가세가 예상된다. 설비투자는 수출 부진의 완화에 힘입어 소폭 증가세가 예상되며, 건설투자는 전년의 높은 증가에 따른 기저효과와 건설규제 등에 따라 증가세가 크게 둔화될 전망이다. 수출은 세계경제의 소폭 개선과 유가 반등에 따른 단가 하락세 진정 등으로 증가세로 돌아설 것이나, 매우 완만한 흐름이 예상된다. 2017년 수출은 2.1%, 수입은 3.6% 증가하면서 무역수지는 전년보다 약간 줄어든 857억 달러의 흑자를 보일 전망이다.

• The Journal of the Korea Contents Association
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• v.18 no.7
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• pp.656-664
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• 2018

The following study was conducted to determine the optimal location in terms of efficiency for solar energy facilities, and to propose a policy implications for the orientation of the installments. 92 cases in Jeollanam-do Province were selected. A regression analysis was performed between the average electricity generation time as the dependent variable, and the facility, weather and site conditions as the independent variables. As a result, 5 variables were deemed significant. Larger site areas, closer proximity to rivers, islands, oceans, etc., least south-oriented, higher average wind speed, and facilities in agricultural land use and natural environment conservation land use had the highest efficiency. This study minimized the possibility of secure databases and errors following facility types, and was limited in the number of sites studied, since this was only conducted in Jeollanam-do Province. Nevertheless, these conclusions still offer important policy implications for determining the most optimal location for solar energy facilities.