• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(III)
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• pp.345-350
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• 2003

The inside of EMU is supplied with the cooling air from air-conditioner and the fresh air from exterior through the air-conditioner duct which is one of the air conditioning system. The shape of air-conditioner duct is a major factor in determining the air-conditioning efficiency, thermal comfort and energy efficiency. Therefore, this study is to understand the flow characteristics in the air-conditioner duct by three dimensional numerical simulation. The air-conditioner duct was calculated for the design volume flow rate, $2,726\;m^3/h/unit$. From the result of calculation and measurement, the velocity at diffuser outlet presented good agreement in general. [n this present study, the calculation was also performed for three volume flow rate(1,800, 2,200, 3,000 $m^3/h/unit$) and total pressure characteristic curve with volume flow rate was presented.

• 약학회지
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• 제2권1_2호
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• pp.33-41
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• 1953

According to the results of the investigation of air condition on a movie hause in Seoul city, for the period August 1948 to August 1949, the results were considerable condition contrary to the expection due to lack of Ventilation. By the above equation, the total air ventilation volume, the avarage air volume of natural ventilation, and the air volume of artifical ventilation to be required of the seven movie hause in Seoul city are discussed (See table in page in this Journal)

• 환경위생공학
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• 제24권3호
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• pp.16-27
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• 2009

In this paper, I examined the level of fine dust in medical institutions, educational institutions and multi-purposed facilities to grasp the exact state of the present, and decided the level of air-borne particulate(KSM ISO Standard and ISO Standard 14644-1). We compared new proposed cleaner equipped with HEPA Filter with general cleaner and analyzed the rate of removal according to height, air volume and the equipment with the compulsive air intake. Through this comparison, I reached the conclusion as follows: 1. According to the examination, the fine dust of medical institutions, educational institutions and multi-purposed facilities in Kwang Ju is class 9. 2. The filter used in general cleaner on the market is that of HEPA-type, and its removal efficiency for fine particles($0.3{\sim}0.5{\mu}m$) is very low. 3. In the removal efficiency of new proposed cleaner equipped with HEPA Filter, the higher it is, the better, especially more than 180cm in height. 4. In case it is operated for 5 minutes under the condition of the space of $9.4m^{3}$ and the maximum air volume equipped with two induction pipes, we can keep the air cleanness level of 5 ~ 6. 5. To maintain the air cleanness for a long time, if we first operate for 5 minutes at maximum air volume and then operate at medium maximum air volume, we can keep the air cleanness with low energy.

• 한국전자통신학회논문지
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• 제16권3호
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• pp.541-550
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• 2021

야적퇴비는 농경지의 작물 양분 공급원으로 가치를 가지는 반면, 강우 시 환경에 악영향을 미치는 오염원으로 작용하게 되며, 이에 대한 관리가 요구된다. 본 연구에서는 광범위 영상 취득 및 자동 경로 비행이 가능한 고정익 무인항공기를 이용한 야적퇴비 적재량 산출 정확도 분석 및 활용 가능성을 파악하고자 하였다. 야적퇴비 3개소에 대한 적재량 산출 정확도를 평가하고자 지상 LiDAR 측량 및 회전익 무인항공기를 이용한 정밀 측량을 수행하였으며, 고정익 무인항공기를 통해 취득된 적재량과 비교하였다. 지상 LiDAR를 기준으로 야적퇴비 적재량 산출 비교 결과 회전익 기체의 오차율은 ±5 %, 고정익 기체의 오차율은 -15 ~ -4 %로 추정하였다. 고정익 기체에서 산출된 1개의 야적퇴비 적재량이 약 -15%로 과소추정 하였으나 야적퇴비 적재량의 편차는 2.9 m3로 큰 차이는 없었다. 또한 고정익 무인항공기를 이용한 주기적인 모니터링 결과 대상 지역에 위치한 야적퇴비 적재량의 시계열 변동 파악할 수 있었다. 이러한 결과는 고정익 무인항공기를 이용한 넓은 범위의 대한 효율적인 야적퇴비 모니터링 및 농경지의 비점오염원 관리가 가능함을 제시하였다.

• 국제초고층학회논문집
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• 제8권1호
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• pp.71-82
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• 2019

The purpose of this study is to evaluate the indoor air quality (IAQ) and energy benefits of a dedicated outdoor air system (DOAS) and compare them with a conventional variable air volume (VAV) system. The DOAS is a decoupled system that supplies only outdoor air, while reducing its consumption using an enthalpy wheel. The VAV system supplies air that is mixed outdoor and transferred indoor. The VAV has the issue of unbalanced ventilation in each room in multiple zones because it supplies mixing air. The DOAS does not have this problem because it supplies only outdoor air. That is, the DOAS is a 100% outdoor air system and the VAV is an air conditioning system. The transient simulations of carbon dioxide concentration and energy consumption were performed using a MATLAB program based on the thermal loads from the model predicted by the TRNSYS 18 program. The results indicated that when the air volume is large, such as in summer, the distribution of air is not appropriate in the VAV system. The DOAS however, supplies the outdoor air stably. Moreover, in terms of annual primary energy consumption, the DOAS consumed approximately 40% less energy than the VAV system.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.417-422
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• 2006

On trends of 'well-being', heat recovery ventilators(HRV) are recently installed in high rise buildings. HRV is not energy saving instrument but ventilating one. But many people have not been aware of the accurate fact. In this study, performances of HRV are tested under foreign and domestic standards. Especially air-tightness is measured three times by using gas concentration method and pressing equipment. Wet effective ventilating air volume is acquired by solving gas concentration equations. After research air-tightness and effective ventilating air volume must be more focused on than heat transfer efficiency to select the optimal HRV. Heat transfer efficiency must be adjusted by air-tightness results.

• 한국환경과학회지
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• 제12권12호
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• pp.1235-1243
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• 2003

Under controlled conditions in an environmental chamber, 24 experiments were performed to compare the ability of a Variable-Air-Volume/Bypass Filtration System(VAV/BPFS) to remove indoor pollutants and to conserve energy with the ability of conventional Variable Air Volume(VAV) system. The specific conclusions of this paper were; first, the VAV/BPFS was more efficient than the VAV system in removing particulate matter, TVOC, and target VOCs. The total effective removal rate of PM for the VAV/BPFS was two times as high as that of the VAV system. The total effective removal rate of TVOC for the VAV/BPFS was 20 percent higher than that of the VAV system. Also each target VOC concentration was reduced by using the VAV/BPFS. Second, clean air delivery rate was increased by using VAV/BPFS due to additional filtration rate. Otherwise, the VAV/BPFS decreased outdoor supply air rate above 25 percent relative to the rate of VAV system. Third, total energy consumption by the VAV/BPFS was lower than that of the VAV system during the period with indoor thermal load, occupied time. The energy saving of the VAV/BPFS ranged from 11 to 16 percent. The VAV/BPFS improves indoor air quality more efficiently than the VAV system, and it reduced energy consumption. Retrofitting the VAV system with the VAV/BPFS was easy The use of VAV/BPFS is, therefore, recommended far buildings with VAV system as well as for buildings at designing stage.

• 한국의학물리학회지:의학물리
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• 제33권1호
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• pp.1-9
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• 2022

Purpose: To evaluate the effective volume of the Korea Research Institute of Standards and Science free air chamber (KRISS FAC) L1 used for the primary standard device of the low-energy X-ray air kerma. Methods: The mechanical dimensions were measured using a 3-dimensional coordinate measuring machine (3-d CMM, Model UMM 500, Carl Zeiss). The diameter of the diaphragm was measured by a ring gauge calibrator (Model KRISS-DM1, KRISS). The elongation of the collector length due to electric field distortion was determined from the capacitance measurement of the KRISS FAC considering the result of the finite element method (FEM) analysis using the code QuickField v6.4. Results: The measured length of the collector was 15.8003±0.0014 mm with a 68% confidence level (k=1). The aperture diameter of the diaphragm was 10.0021±0.0002 mm (k=1). The mechanical measurement volume of the KRISS FAC L1 was 1.2415±0.0006 cm³ (k=1). The elongated length of the collector due to the electric field distortion was 0.170±0.021 mm. Considering the elongated length, the effective measurement volume of the KRISS FAC L1 was 1.2548±0.0019 cm³(k=1). Conclusions: The effective volume of the KRISS FAC L1 was determined from the mechanically measured value by adding the elongated volume due to the electric field distortion in the FAC. The effective volume will replace the existing mechanically determined volume in establishing and maintaining the primary standard of the low-energy X-ray.

• Spatial Information Research
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• 제6권1호
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• pp.65-76
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• 1998

대기오염을 관리하기 위해서는 대기오염 농도와 함께 대기오염 배출량의 공간분포가 정확히 산정되어야 한다. 기존의 대기오염 분포도에서는 토지이용 분류도의 해상도(rdsolution)가 낮아 같은 위치에서 오염원별 토지이용이 중복되었기 때문에 배출량의 정확한 공간분포를 산정할 수 없었다. 본 연구에서는 토지이용분류도를 고해상도(28.5m x 28.5m)로 작성하므로써 이것이 배출량의 공간분포 산정과 대기오염농도의 추정에 미치는 영향을 파악하였는데, 결과를 요약하면 다음과 같다. GIS를 이용하여 비교적 고해상도(28.5m x 28.5m)의 토지이용 분류도를 작성하므로써 점 및 선 오염원이 면 오염원과 동일한 지점에서 중보되지 않도록 토지이용을 효율적으로 반영할 수 있었다. 서울지역에 대해 기존으 방법으로 작성된 배출량 분포도와 본 연구에서 작성된 배출량 분포도를 이용하여 대기오염 농도를 추정(TCM-2모형을 이용)한 결과 본 연구에서 작성한 배출량 분포도에 의한 대기오염 농도의 추정지가 자동측정망의 실측치에 근접함을 알 수 있었다.

• 산업경영시스템학회지
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• 제43권4호
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• pp.15-22
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• 2020

Economic indicators are a factor that affects air cargo volume. This study analyzes the different factors affecting air cargo volume by each Chinese cities according to the main characteristics. The purpose of this study is to help companies related to China, airlines, and other stakeholders predict and prepare for the fluctuations in air cargo volume and make optimal decisions. To this end, 20 economic data were used, and the entire data was reduced to 5 dimensions through factor analysis to build a dataset necessary and evaluated the influencing factors by multi regression. The result shows that Macro-Economic Indicators, Production/Service indicators are significant for every cities and Chinese manufacture/Customer indicators, Korean manufacture/Oil Price indicators, Trade/Current indicators are significant for each other city. All adjusted R2 values are high enough to explain our model and the result showed excellent performance in terms of analyzing the different factors which affects air cargo volume. If companies that are currently doing business with China can identify factors affecting China's cargo volume, they can be flexible in response to changes in plans such as plans to enter China, production plans and inventory management, and marketing strategies, which can be of great help in terms of corporate operations.