• 설비공학논문집
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• 제21권2호
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• pp.103-108
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• 2009

Local exhaust system used in toilet and cooking place of low-rise public house installed roof ventilator at terminal of stack. There are many high riser public houses in Korea. These buildings were not viewed as being major contributors to exhaust pollutants producted in indoor. It was because many engineers thought that exhaust in high riser public house depends on stack effect. But Neutral pressure level represents in a terminal of stack with air tightness for the best exhaust efficiency. Thereby, lower floors have the worst indoor air quality. This paper focuses mainly on the exhaust efficiency improved by roof fan with motor installed in high riser public house. It is observed there is higher exhaust efficiency than the existing natural roof ventilator.

• 한국철도학회논문집
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• 제5권2호
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• pp.112-117
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• 2002

Reduction of noise level in the cabin of urban transit unit is an important issue to enhance the comfortability of passengers. It is made clear that a cause of increased noise level in cabin is the imperfect airtightness of entrance doors. In this study, the sliding-plug door system is developed to reduce the noise level of cabins by securing the airtightness of entrance door. The sliding-plug door system is composed of air-driven engine, swing arms, guide rails, guide rollers and locking devices. It is economical owing to using the previous door engine system. It is also adequate for the platform system of our subway station. It was tested to prove the reliability of system and was applied to standard urban transit unit. The effectiveness of noise reduction in cabin resulting form the sliding-plug door system was confirmed by test results.

• 한국안전학회지
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• 제17권4호
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• pp.119-125
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• 2002

The concept of dwelling space is tend to be changed not only to have reasonable mobility but also to have high quality of indoor air with psychologicaa satisfaction and comfortable. Moreover, recent constructed buildings have a big problem because of exhausted pollution gas and particles from building materials. More serious problem occurs from its high air tightness reducing the ventilation for saving the energy and superior adiabatic insulators to have high heat efficiency. Indoor air quality in super high-rise dwelling house was investigated by measuring pollutants such as $CO_2,=;CO,\;MO_2,\;R_n,\;TSP,\;PM_{10}$, HCHO, Offensive ordor. Subjective evaluation of residential environment is processed for the inhabitants who live in research space by testing environmental load in accordance with environment morphology, exterior environmental factor and post occupancy correlation and influence of attention.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.2
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• pp.243-246
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• 2006

This study investigates the improvement in the theoretical success rate of the integer ambiguity resolution in GPS/GNSS carrier-phase positioning by using many visible satellites. It estimates the dependence of the rate on the baseline length in relative positioning under the condition of the use of double/triple-frequency navigation signals. The calculation results show that the use of 14 navigation satellites (i.e., seven GPS and seven Galileo ones) remarkably improves the success rate under the condition of very short baseline length, compared with the use of seven GPS ones. The numerical reliability of the calculated success rates is strictly tested by examining the tightness of the union and minimum-distance bounds to the rate. These bounds are also shown to be effective to investigate the realization of the high success rates.

• 터널과지하공간
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• 제4권2호
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• pp.192-200
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• 1994

Underground offers many advantages for storing agricultural and marine products. Since it is confined by thick walls of rock it is easy to control temperature and humidity and to achieve air and water tightness. Also, damages by rodents and insects could be avoided. Flexibility in choosing the location is another advantage that underground could offer. Consequently the goods could be stored near the big city to meet the demand change. Because of these advantages, many underground food storage facilities were built and operated successfully in U.S. and many Euroupean countries. On the other hand, there is no underground food storage facilities in Korea despite the need is growing rapidly. This paper describes the case studies of foreigh food storage and technologies related to food storage were analyzed and evaluated. Also performed is analysis of domestic technologies for construction and operation of underground food storage facilities to deduce the fields of studies that have to be conducted.

• 한국태양에너지학회 논문집
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• 제28권5호
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• pp.65-71
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• 2008

The purpose of this study is to investigate an airtightness of typical Korean detached houses with field measurements. Air leakage testings by means of blower door test in accordance with ASTM E79-8 were measured in 22 detached dwellings in Daejeon and Geumsan. The results showed that detached dwellings have an average airtightness with ACH50/20 (air chang per hour at a pressure difference of 50 Pa between inside outside) of 0.82 $hr^{-1}$ which is a higher range than for typical apartments and leakage class G by normalized leakage area of ASHRAE.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.814-819
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• 2006

This research is on the design and introducing of integrated thermal performance of super energy saying building, called 3 Liter house which can be sustained with 3 liter oil(kerosene) per $yr.m^2$. 3 liter houses(Passive houses) offer extended living comfort with only 15 to 20% of the space heating demand of conventional new building. To achieve this purpose, the efficiency of building components is improved, such as walls, windows or ventilation system and the construction technology is improved, such as the prevention of thermal bridge and the air tightness. The fuel cell is used as alternative energy. Energy consumption of 3L house is 2.08 [liter/$yr.m^2$] in monitoring result of $2006/2/1{\sim}2/7$ and ACH50 is 0.67 in result of Blow Door Test, therefore 3L House is well- insulated and well- airtighted house.

• 한국산업융합학회 논문집
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• 제25권2_2호
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• pp.279-287
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• 2022

Butterfly valves installed on ships use valves with up to triple offset to improve tightness. However, the triple offset valve has structural problems such as disc deformation and seat separation. Accordingly, interest in quadruple offset butterfly valves with added offset is increasing. In this study, the structural safety of the quadruple offset butterfly valve was examined through numerical analysis. In addition, we intend to evaluate the performance of the valve through flow coefficient analysis.

• 대한물리치료과학회지
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• 제29권2호
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• pp.14-19
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• 2022

Background: Plank exercise (PE) is an effective exercise to enhance lower back stability by strengthening the core and lower limb muscles. However, in patients with a shortened hamstring muscle (HAM), PE may cause abnormal movement of the pelvis and lower back due to HAM hyperactivity. Therefore, the objective of this study was to investigate the effects of PE on the core muscles and HAM in subjects with a shortened HAM. Design: Cross-sectional study. Methods: Subjects were divided into a normal length of HAM group (NHG; 9 subjects) and a shortened length of HAM group (SHG; 14 subjects). The activities of the erector spinae (ES), rectus abdominis (RA), external oblique (EO), and HAM muscles were measured using surface electromyography. Results: The results showed that RA, EO, and ES muscle activities were higher in the NHG than in the SHG; however, no significant differences were detected. Conclusion: HAM activity was significantly higher in the SHG than in the NHG. In subjects with a shortened HAM, PE may hyperactivate the HAM, adversely affecting the pelvis and lower back.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 봄 학술논문 발표대회
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• pp.140-141
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• 2022

CFD analysis was performed to analyze the temperature distribution of the inner space of the curing house according to blocking the opening of the gang-form with a tent in case of concrete pouring and heat curing of the apartment house during the winter season. If the gang-form opening is closed with a tent during internal heating using a hot air blower in the winter, the internal temperature rises compared to the non-reserved due to air-tightness of the curing spaces, and uniform temperature distribution can be ensured. In addition, it is possible to increase curing efficiency by reducing the amount of heat supplied and shortening the heating time.