• 한국농공학회논문집
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• 제59권3호
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• pp.71-81
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• 2017

Organic dust generated inside livestock facilities includes toxic organic matters such as bacteria and endotoxin. Dust can cause respiratory disease for worker and livestock, and consequently, degradation of welfare and productivity. Influence of dust on livestock workers has been studied since the 1970s. However, exposure limit for cattle farmer has not been established, unlike exposure limit for pig and poultry farmer. Furthermore, study on air quality inside livestock facility, especially inside dairy farm has been rarely conducted in Korea. In this study, dust concentration of TSP, PM10, inhalable and respirable dust has been monitored in the commercial dairy house according to location and working activities. Bedding material inside the stall was one of the major sources of dust. The amount of dust was related to water content level of the bedding material. Dust concentration was relatively high in leeward location, and the highest concentration was measured during TMR mixing process. The maximum value of inhalable dust concentration was 29.1 times higher than the reference value as fine particles drop to the TMR mixer. Dust generated by TMR mixing was presumed to decrease by adjusting moisture and drop height of feed.

• Journal of Biosystems Engineering
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• 제15권3호
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• pp.177-185
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• 1990

The break of rotary blade is occured from a stress concentration of the inside of blade by the outside impulsive load. In order to examine its inside stress and stress concentration of rotary blade, a epoxy plate which is suitable to applicate by photoelastic system is used to experiment. These results are summarized as follow. 1. Refer to the existence of bolt hole and a size of its of rotary blade, a stress concentration which cause the break of rotary blade is not exposed. 2. It is expected to be break to section of hold of rotary blade and the break of this is due to that there are concentrated by shearing force, bending moment and bending stress. 3. When the crack which caused from processing are set up to any location, the stress concentration taken to the creak point. 4. Without regard to the location of the reaction points of rotary blade, the bending stress which is greated than the bending moment is occured within about 6 em toward the center line of bolt hole and it was possible to break that section.

• 한국경제지리학회지
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• 제2권1_2호
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• pp.27-45
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• 1999

최근 제조업의 수도권의 집중, 서울에서 경기지역으로 분산과 경기직역의 성장, 수도권질서 첨단산업으로의 구조재편과 중소기업의 집적, 그리고 농촌지역에서의 대기업 분공장 입지 등의 현상에 대해 우리나라 경제발전의 역사과정의 맥락에서 구조적 접근을 통해 살펴보았다. 그 결과 자본의 국제적 이동과정질서 신국제분업과 경제성장은 한국의 공간구조를 불균등하게 조직하였고, 그리고 지속적인 경제성장에 따른 자본축적은 지가상승, 임금상승 그리고 노동재생산기반의 지리적 차이와 산업의 공간분업을 발생시켰다. 이러한 변화된 요인에 의해서 오늘날 제조업 입지변화를 설명할 수 있다. 따라서 향후 지식기반과 관련된 사회문화적 구조와 지가와 관련된 토지이용구조의 입지요인들이 더욱 구조적으로 연구가 진행되어야 할 것이다.

• 한국환경보건학회지
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• 제41권6호
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• pp.389-396
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• 2015

Objectives: A hospital is a complex building that serves many different purposes. It has a major impact on patient's well-being as well as on the work efficiency of the hospital staff. Thermal comfort is one of the major factors in indoor comfort. The purpose of this study was to determine thermal comfort in various locations in a hospital. Methods: Various indoor environmental conditions in a general hospital were measured in February 2014. The predicted mean vote (PMV) and carbon dioxide ($CO_2$) concentration were measured simultaneously in the lobby, office, restaurant, and ward. Results: The ward was the most thermally comfortable location (PMV=0.44) and the lobby was the most uncomfortable (PMV = -1.39). However, the $CO_2$ concentration was the highest in the ward (896 ppm) and the lowest in the lobby (572 ppm). The average PMV value was the most comfortable in the ward and the lowest in the lobby. In contrast, for concentration of carbon dioxide, the highest average was in the ward and the lowest in the lobby. Due to air conditioner operation, during operating hours the PMV showed values close to 0 compared to the non-operating time. Correlation between PMV and $CO_2$ differed by location. Conclusion: The PMV and concentration of carbon dioxide of the hospital lobby, office, restaurant and ward varied. The relationship between PMV and carbon dioxide differed by location. Consideration of how to apply PMV and carbon dioxide is needed when evaluating indoor comfort.

• 기술혁신학회지
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• 제10권2호
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• pp.310-333
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• 2007

이 논문은 우리나라 주요 대학의 과학기술 분야의 연구개발 활동에 대한 상대적인 비교우위와 종합적인 특성화 정도를 살펴 볼 수 있는 지수들을 통해 정부의 연구개발비 수혜 규모, 수도권과 지방 소재여부, 국공립과 사립으로 구분한 경우 특성화의 정도에 대한 차이가 있을 것인가에 대한 가설을 검증하고 검증 결과에 대한 정책적 의미를 살펴본다. 정부의 재정지원 규모가 클수록 종합적인 특성화의 정도는 약화되는 것으로 분석되었다. 그러나 소재 지역의 구분은 특성화의 차별화에 영향을 주지 않는 것으로 밝혀졌다. 한편, 국공립 형태의 대학군이 종합적인 특성화가 상대적으로 심화되어 있는 것으로 분석되었다. 이 논문의 검증 결과가 주는 정책적 시사점은 추후정부의 특성화 정책 관련 세부추진 방향과 전략에 도움이 될 것으로 판단이 된다. 이를 위해서는 이 연구에서 제안하는 상대비교우위 및 종합적 특성화와 함께 개별 연구주체인 각 대학들의 전반적인 그리고 개별적인 연구개발 활동의 우수성에 대한 분석이 병행되어야 할 것으로 생각한다. 아울러 그동안 정부의 대학 특성화 정책추진 성과에 대한 종합적인 분석이 이루어져 정책에 대한 실효성이 검증이 되어야 한다.

• KIEAE Journal
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• 제5권3호
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• pp.41-48
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• 2005

Before occupation of an apartment housing, the builders are required to inform the test result of IAQ to the public. However, there is no simplified method to predict IAQ before measurement of pollutant concentration. In this study, a simplified way of predicting IAQ based on the distribution of indoor pollutant concentration is proposed. 7 different cases of air change rate have been simulated through CFD analysis to get the distribution ratio of each pollutant material and then simplified functions were used with CRIAQ1 values derived from CFD simulation to evaluate by comparing the influence of each material in the indoor pollutant concentration. Again, a lot of efforts which can improve the indoor air quality have been performed. Materials used in indoor space are labeled with their pollutant emission level. Installation of ventilation system in residential buildings will be regulated by a building codes sooner or later. But it is important to understand the fact that layout of walls, location or size of openings will influence the indoor air flow and pollutant concentration. And location of emitting material influences to indoor air pollutants distribution. But until now there is few recognition and consideration of these factors. Therefore, in this paper the effects of these factors is proved and some kind of guideline is made for designers after a comparison of typical apartment floor plan and a new type plan with their average pollutant concentration and its distribution of each room. CFD(Computational Fluid Dynamics) program was used to show the indoor air flow and pollutant concentration distribution. For this purpose, a typical $100m^2$ apartment floor plan was chosen as a case study model and several alternatives were reviewed to improve the IAQ performance. The simulation took place in the condition of natural ventilation through windows.

• 대한기계학회논문집A
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• 제31권3호
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• pp.344-354
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• 2007

The objective of this study is to investigate the effect of arbitrarily located defect around the circular hole in the aircraft structural material such as Al/GFRP laminates and monolithic Al alloy sheet under cyclic bending moment. The fatigue behavior of these materials may be different due to the defect location. Material flaws in the from of pre-existing defects can severely affect the fatigue crack initiation and propagation behavior. The aim of this study is to evaluate effects of relative location of defects around the circular hole in monolithic Al alloy and Al/GFRP laminates under cyclic bending moment. The fatigue behavior i.e., the stress concentration factor($K_t$), the crack initiation life($N_i$), the relationship between crack length(a) and cycles(N), the relationship between crack growth rate(da/dN) and stress intensity factor range(${\Dalta}K$) near a circular hole are considered. Especially, the defects location at ${\theta}_1=0^{\circ}\;and\;{\theta}_2=30^{\circ}$ was strongly effective in stress concentration factor($K_t$) and crack initiation life($N_i$). The test results indicated the features of different fatigue crack propagation behavior and the different growing delamination shape according to each location of defect around the circular hole in Al/GFRP laminates.

• 전기학회논문지
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• 제64권3호
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• pp.365-369
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• 2015

In this paper, geographic information system(GIS) for an intelligent power distribution network was implemented with location informations acquired from automatic meter reading system, where the location informations of power line communication(PLC) modems installed at customer side were collected at data concentration units(DCUs) of headend equipment via PLC and then were transmitted to front end processor server. By displaying the connection status of the power distribution network on GIS map, operation of advanced metering infrastructure(AMI) or management of power grid system could be performed intuitionally and in real time, because the configuration state of the power grid could be easily monitored. The feasibility of the proposed system was confirmed with the especially constructed laboratory-level test bed and the verification test of the system will be carried out for a real power distribution network.

• 설비공학논문집
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• 제19권5호
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• pp.386-393
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• 2007

This paper studies the ventilation characteristics according to the jet fan location at the long road tunnel using the CFD software 'FLUENT' which is based on the finite volume method. The tunnel model used in the analysis has a length of 1600m, a cross sectional area of $120m^3$, and is composed of 3 lanes and one way. The velocity profile, the distribution of CO concentration and the ventilation flow rate within the tunnel are analyzed, respectively. In the analysis, it is found that the dependence of the ventilation flow rate upon the jet fan location is small, but the CO concentration in the tunnel is at the lowest when the jet fans are installed near the tunnel outlet. An air stream right below the jet fan is almost inactive due to the strong stream injection near the jet fan. Thus, the pollution level below the jet fan must be higher than the other area.

• Journal of Advanced Marine Engineering and Technology
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• 제26권4호
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• pp.472-484
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• 2002

To analyze the characteristics of air flow and $CO_2$ extinguishant transfer when extinguishant is injected into a closed space similar to marine engine room, a numerical simulation on a space was performed. Flow fields and $CO_2$ concentration fields are calculated according with the variation of the location & injection angle of nozzles. The results of simulation showed that the pattern of recirculation flow was affected greatly with the location & injection angle of nozzles and such a recirculation flow accelerated mass transfer of $CO_2$ and greatly affected the diffusion process of $CO_2$ extinguishant. It is considered that this result of this study can be useful to designing the arrangement of nozzles for the $CO_2$ fire fighting equipments in a marine engine room.