• 한국소음진동공학회논문집
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• 제17권8호
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• pp.726-735
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• 2007

Inside the factory buildings of aprecision industry (which produces semiconductors or TFT-LCD), thousands of vibration-sensitive precision equipments operate in the clean rooms. Various utility equipments that are installed around them for proper operation cause various sources of noise and of vibration to exist inside the clean rooms and thus deteriorate the noise and the vibration environment within. In this study, we check if the existing transient vibration phenomenon is caused by the vibrations that arise from operating the utility installed near these equipments; compare and evaluate the vibration criteria of precision equipments regarding the transient vibration phenomenon; and check the efficiency of these criteria.

• 반도체디스플레이기술학회지
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• 제2권2호
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• pp.25-30
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• 2003

In the case of a vibration sensitive equipment, it require a vibration free environment to provide its proper function. Especially, lithography and inspection device, which have sub-nanometer class high accuracy and resolution, have come to necessity for producing more improved Giga Class semi conductor wafers. This high technology equipments require very strict environmental vibration criteria in proportion to the accuracy of the manufacturing. In this paper, the dynamic analysis and modal test were performed to evaluate the dynamic properties of the constructing clean room structure. Based on these results, a structural dynamic modification(SDM) were required to satisfiy the vibration allowable limit for pression machine. Therefore, in order to improve the dynamic stiffness of clean room structure, the VSD system which can control the force applied on structure, were adopted and its utility were proved from dynamic test results of the improved structure after a modification work.

• 노동경제논집
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• 제31권3호
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• pp.21-46
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• 2008

본 논문은 산업재해에 대하 예방을 강화하기 위해, 산업재해율이 상대적으로 높은 50인 미만 영세 제조업체를 중심으로 2001년 이후 보조금을 지급한 클린사업장 조성사업의 순수한 산재 감소효과를 추정하기 위해 작성되었다. 본고의 분석 결과에 따라 가장 신뢰도가 높은 추정방법인 (1) 선택 편의를 통제하기 위하여 클린사업장 1년 전의 자료를 제외하고 (2) 고유 효과(fixed effect) 차분모형을 이용한 회귀분석을 사용한 결과를 중심으로 분석한 결과 클린사업장으로 인정된 사업장의 인정 이전 산재발생률이 0.34%포인트 정도 하락하는 것으로 추정되었음을 감안할 때 산재발생률에서는 15.8% 감소한 것으로 보아야 할 것이다.

• Ocean and Polar Research
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• 제24권4호
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• pp.399-406
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• 2002

Trace metals were investigated for the surface seawaters and mussels collected in adjacent sea to the Dokdo during 1999-2000. This study reports the temporal and spatial distributions of trace metals in seawaters and mussels of the Dokdo coastal areas. Clean technique for trace metal analyses was employed in all manipulations including the sampling and pretreatment procedures. The concentrations of dissolved Cu, Cd and Pb in the surface seawaters were similar to those of the previous data in the East Sea. Contents of particulate Al, Fe, Mn and Co were influenced by input of detrital materials from the Dokdo. The average EFs of particulate metals were to the order of Cd > Zn > Pb > Cu > Ni > Mn > Co > Fe, and the high values in Cd and Zn may be closely related to the preferential uptake of biogenic particles. With the exception of Cd, all metal contents in the mussels were in the same ranges with those from other world coastal areas. The Cd accumulation factor of mussel/seawater in this study was abnormally much higher than previous data from the Korean coasts.

• 한국대기환경학회지
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• 제25권5호
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• pp.410-419
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• 2009

Generally, air pollutant emission at workplace is estimated by two methods: indirect methods using emission factors and direct methods based on CEMS (Continuous Emission Monitoring System). CAPSS (Clean Air Policy Support System) is a representative indirect method and the national air pollutant database of Korea. However, characteristics of some workplaces may create a gap between CAPSS and CEMS data. For improving of emission data accuracy, emission data of CEMS (named CleanSYS) equipped at 138 target workplaces were compared with those of CAPSS. As a result, $SO_x$ and $PM_{10}$ emission levels obtained by CAPSS were lower than those of CleanSYS. $SO_x$ and $PM_{10}$emission ratios were 61.5% and 71.2% lower respectively, showing the biggest gaps. On the other hand, $NO_x$ emission of CAPSS was higher by 10.4%. $SO_x$ showed the biggest difference in 'Energy industry combustion' and $NO_x$ did in 'Production Process' within the SCC category. $PM_{10}$ presented a large gap in 'Manufacturing industry combustion.' The differences in $SO_x$ between the two systems occurred because some large-size facilities lack pollution controllers or efficient pollution controllers. Based on this study, CAPSS emission database of Korea will improve accuracy through adopting CEMS emission system, which enables more efficient national atmospheric policies and workplace management.

• 한국환경생태학회지
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• 제12권4호
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• pp.389-397
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• 1999

본 연구는 한려해상국립공원의 이용객 행태를 분석하기 위해 수행되었다. 이를 위해 자체 개발한 설문지를 이용한 설문조사를 1998년 8월 21일부터 8월 23일까지 실시하였다. 설문조사에는 한려해상국립공원의 거제, 통영, 남해, 오동도 지구를 방문한 303명의 이용객이 참여하였다. 응답자의 남녀비율, 교육 및 소득수준, 연령별분포 등 사회경제적 특성은 타 국립공원에서 실시된 이용객 조사결과와 유사한 경향을 보였다. 이용객에 의한 공원 내에서의 쓰레기 불법투기는 이용자들의 습관적 행위에 기인한다는 인식이 높았으며, 현재 시행중인 Clean-up-Time운동에 대한 이용객의 인식은 낮은 것으로 나타났다. 한려해상국립공원에서 이용객들의 휴양경험에 영향을 미치는 영향인자들로서 생태계 보전상태, 자연경관의 질, 쓰레기 문제, 안전성, 공원관리자의 친절이 제시되었으며, 이들 인자들에 대한 이용자 만족도는 응답자들의 기대수준에 못 미치는 것으로 나타났다. 그러나 이용객들은 전반적인 휴양경험에 대해 비교적 만족하는 수준으로 나타났다.

• 문화기술의 융합
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• 제9권1호
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• pp.191-197
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• 2023

본 연구의 목적은 반도체 생산라인-클린룸에 활용할 수 있는 가상현실 실습 콘텐츠 제작 설계, 제작과정에 관한상 교육환경을 제공을 목표로 진행하였다. 사용자는 본 과정을 통하여 클린룸 입장 전후의 절차적 지식과 함께, 반도체 솔라셀 주요 제조설비를 직접 체험하는 등 실제에 가까운 체험을 통한 실제적 지식을 습득할 수 있다. 특히 반도체 및 솔라셀 제조공정에 필요한 체험 콘텐츠와 클린룸 입실 절차 체험 콘텐츠 환경 조성하여 사용자에게 실제에 가까운 몰입 경험을 제공하며, 이는 교육의 몰입감, 실재감, 교육의 비용, 효율성 및 교육 만족도 향상을 기대 하였다. 이러한 실감 콘텐츠의 몰입감, 상호작용, 지능화 등 그 특징에 따라 고위험(Dangerous), 체험불가(Impossible), 고대가성(Counter-productive), 고비용(Expensive) 분야에 활발히 적용될 것으로 예상되며, 실감 콘텐츠 학습자가 학습내용에 몰입하게 하고, 주도적/능동적 학습을 유도함은 물론 학습내용을 체화시켜 교육효과 증진 부문에 긍정적인 성과를 기대 하게되었다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.383-386
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• 1997

Electrostatic suspension is a method to levitate an object by using electrostatic forces. Its main advantage is to levitate objects without any mechanical contact which fulfills the requirement of an object handling in ultra clean environment. In this paper, the electrostatic suspension system for film-like thin plate such as aluminum sheet, is designed and controlled. In contrast with the conventional electrostatic suspension system which requires the costly and bulky high-voltage amplifiers, it is suggested to use the switching voltage control method in consideration of real industrial application for the handling of such flexible bodies. Some experimental results show that the developed electrostatic suspension system shows good performances to levitate flexible film-like thin plate.

• 한국대기환경학회지
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• 제14권6호
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• pp.621-630
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• 1998

The concentrations of organic carbon (OC) and elemental carbon (EC) in fine aerosols were determined from the samples collected at the two background sites of Kosan in Cheju Island and Kangwha. Samplings were carried out during the spring and winter of 1996 and the fall and winter of 1997. PM25 particles were collected on the prefired quartz filters for 24 hours and analyzed by the selective thermal oxidation method. The concentrations of OC at the sites were higher than those commonly observed from clean areas around the world, but those of EC at both sites were lower than, or comparable to, other clean areas in the world. Both the OC and EC levels at Kangwha were higher than those at Kosan. According to backward trajectory analysis, most air pollutants collected at the two sites were from China. It was found that the OC and EC concentrations in air masses from southern China were higher than those from northern China.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 1998년도 공동 심포지엄 및 추계학술발표회
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• pp.48-51
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• 1998

This paper presents the transport and removal of organic substances from the contaminated soft soils and sludges such as marine dredging waste, marine sediments, mine tailing waste, and sewage sludge by electroosmosis. A series of laboratory experiments including variable conditions such as contamination levels, solid contents, and applied voltage rates were peformed with the contaminated soft clay specimen mixed with organic substance. Investigated are specimen density, dewatering rate, outflow rate, and outflow concentration. The test results showed that organic substances in the soils were removed by applied voltages. The results indicated that this process can be used efficiently to clean up the contaminated soil.