• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.3
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• pp.152-157
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• 2015

Stack effect on high-rise building have negative effect on living environment, energy and life-safety aspect. Thus, it's necessary to find the measure to reduce the stack effect. As a result of field test on a 31-story building, a circulating type stack effect reduction technology was developed, which supplies air in the low stairs and discharges air in the high stairs. To evaluate the performance of this circulating type stack effect reduction technology on building stairs, a 3D numerical analysis was carried out by using Momentum Loss Model for analyzing leakage flow between compartments in a building. Consequently, numerical analysis proved that the stack effect on building stairs was reduced by a circulating type stack effect reduction technology.

• The Journal of Information Systems
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• v.21 no.2
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• pp.73-96
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• 2012

With emergence of smart technologies(e.g., smartphones), Location-Based Services(LBS) are expected to provide more enhanced values utilizing consumers' personal information than other smart services. However, in contrast to existing smartphone applications, LBS could raised severe consumer's privacy concerns because of rapidly changing information sensitive to consumers. In this context, the purpose of this study is to explore relationships among privacy concerns reduction, trust and intention to use LBS by examining the effect of precedence factors(social presence, reputation, mobile literacy, ability of information control) of privacy concern reduction. In addition, the study investigates the role of personal innovation as a moderating effect between privacy concern reduction and intention to use LBS. The results showed that the proposed precedence factors of privacy concerns with a exception of Mobile Literacy had a positive impact on privacy concerns reduction that then positively affected trust and intention to use LBS. In addition, the relationship between trust and intention to use LBS was significantly supported. Finally, personal innovation as a moderating effect significantly influenced the relationship between privacy concern reduction and intention to use LBS. This study is expected to be a reference for a subsequent study about the spread of LBS application of smartphone. Also, the finding of this study is meaningful for helping service direction to firms providing LBS.

• Journal of the Korea Safety Management & Science
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• v.20 no.3
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• pp.1-9
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• 2018

This study is intended to look into the effect of construction safety supervision system on risk control and reduction. To achieve this, a survey was carried out to 114 companies in construction, ordering, contract and management. The overall findings were as follows. The effect of construction safety supervision system on risk control and reduction showed that factors of supervision system, supervision cost and supervision method had a positive effect on risk control and reduction. And their perception of the introduction of safety supervision system in construction sites according to process showed that there was a difference between them according to the field of ordering, contract and supervision. There was the biggest difference between owner and contractor in double supervision system, but no difference between them in the perception of risk reduction. These results show that all ordering, contract and supervision are positively needed for the introduction of construction safety supervision. This means that there is a difference between owner and contractor in the perception of process according to system operation. All companies agree to system improvement by the settlement of safety supervision system for the prevention of safety accidents and safe construction, but the systematic complement of safety supervision is the burden of contractor. And there is a big difference between owner and contractor in the perception of responsibility and concern for cost burden.

• Journal of People, Plants, and Environment
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• v.23 no.3
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• pp.363-375
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• 2020

Background and objective: Recreation or activities in forest are regarded as therapy. Many forest therapy programs have been developed and assessed in the domestic. This study was conducted to investigate the effect of the forest therapy program on academic and job-seeking stress in college students. Methods: Thirty five subjects were selected as the experimental group and 25 as the control group, and 29 subjects in the experimental group and 11 in the control group participated in the follow-up test to verify the persistence of stress reduction effects. The forest therapy program was carried out once a week for 2 hours each from September 4 to December 4, 2018, adding up to total eight sessions. Results: The experimental group showed statistically significant reduction in both academic stress and job-seeking stress, whereas the control group did not. For the persistence of the forest therapy program, the experimental group did not show a statistically significant difference between the posttest and the follow-up test, and thus the stress reduction effect was maintained. Conclusion: This study proved the reduction of academic and job-seeking stress in forest therapy programs and the persistence of the stress reduction effect of the forest therapy program. The result is consistent with the Stress Recovery Theory (SRT) that shows the stress reduction effect of nature. In addition, it has significance in that it has verified that the program using the forest on campus can reduce stress of most college students.

• Journal of the Korean Society of Hazard Mitigation
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• v.3 no.2 s.9
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• pp.139-145
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• 2003

This study is to propose reduction effect of scour depth and a optimum size of circular collar through experimental analyses with various collar sizes. To do so, we carried out hydraulic model experiments. In the case of with considering the collar, the effect of reduction of scour depth increased according to the increase of collar size. When size of collar is 2 as the ratio of collar diameter(W) to pier diameter(D), scour depth is decreased about 67% and deposition height is increased about 70%. The optimal size of collar proposed in this study is W/D=2 by analyzing reduction effect of scour depth, size of scour hole, and deposition height.

• Journal of Environmental Health Sciences
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• v.8 no.2
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• pp.33-46
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• 1982

This experiment was carried out for the purpose of reducing alkaloid in reconstituted tobacco sheet and effluent of reconstituted tobacco sheet manufacturing company by treating oxidizing agents such as ozone, sodium hypochlorite, perchloric acid and hydrogen peroxide to tobacco extract created from the manufacturing process of reconstituted tobacco sheet. The effect of alkaloid reduction in tobacco extract by the volume added, time of treatment and pH of oxidizing agents were as follows: 1. When the solid rate of tobacco extract stood at 10 percent, the content of alkaloid, total sugar, total nitrogen and chlorine was 1,600mg/l, 11,000mg/l, 3,200mg/l and 4,000mg/l, respectively. 2. The effect of alkaloid reduction through ozone treatment was in proportion to time of ozone treatment. Alkaloid showed a 31.2 percent reduction under 8 hours' ozone treatment and 0.23g ozone consumed to remove lmg alkaloid. 3. Alkaloid reduction through sodium hypochlorite treatment was influenced by quantity of chlorine in sodium hypochlorite solution. To remove lmg alkaloid, 36.3mg chlorine was used. Reduction of alkaloid was not affected by time of sodium hypochlorite treatment, while showed the best reaction under pH 5-7. 4. The effect of alkaloid reduction by perchloric acid was under the control of the volume added and time of treatment of perchloric acid. The volume of perchloric acid required to remove alkaloid was on the decrease as time of treatment was getting longer. lmg alkaloid was removed by 0.15g perchloric acid under 8 hours' perchloric acid treatment. 5. Alkaloid reduction reacted slowly to the volume added and time of treatment of hydrogen peroxide. Under 8 hours' hydrogen peroxide treatment, it showed maximum removal, registering 10 percent alkaloid reduction.

• Journal of Korean Society of Forest Science
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• v.104 no.4
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• pp.615-621
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• 2015

This study was conducted to analyze accessibility and reduction effect of forest operations cost before and after forest road construction based on actual silvicultural operations in 5 regional forest service(8 management planning district) where forest operations was enacted consistently. The result show the accessibility and the reduction effect of the operation cost, the accessibility of forest operation area within 500 m from forest road or public road increased about 3.2 times after the forest road construction. The reduction effect of the operation cost was averagely 576,000 won/km/year. According to the results, forest road had an effect on improvement of accessibility and reduction effect of forest operation cost. This result could be offered basic information to support policy of forest road expansion.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.187-192
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• 2006

The effect where the multiple sound arrest ing goes mad to the human being does the zone. From like that cotton, this dissertation the both sides flag executed the research regarding a sound arresting reduction in the object in one example. It compared the piping structure which generally is space-time and a specific piping structure and it tested and research and the modeling regarding a sound arresting reduction the simulation which leads and it executed result and comparison of existing it analyzed. The duplication where the reduction effect is bigger the result general VG2 piping structure than escape it did with the fact that it appears the large effect the piping structure which it connects. Also, the straight pipe effect of multiple sound arresting could not go mad with the fact that.

• Solar Energy
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• v.19 no.1
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• pp.37-45
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• 1999

As polymer added in flow, the phenomenon of drag reduction effect was found by many experiments and studies. We divided polymer into three molecular weight($2{\times}10^5,\;4{\times}10^5,\;5{\times}10^5$) and into four concentration(1, 5, 10, 20wppm), then we measured the drag reduction effect in the range Reynolds Number with $30000{\sim}60000$. Finally we found that the most effect drag reduction was that molecular weight is $2{\times}10^5$ with 10wppm concentration. Then the concentration was according to PEO molecular weight, and in general DR increase according to Reynolds Number.

• Fire Science and Engineering
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• v.25 no.5
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• pp.14-20
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• 2011

As the height of the building increases, the stack effect in stairwell that is main facilities for evacuation becomes stronger. While the pressure rise in stairwell causes difficulties on opening the door for evacuation and has effect on smoke control system, reduction of stack effect will be necessary for providing more safe evacuation environment. The field experiments on pressure field in high-rise building are carried out to present reduction method of stack effect and the numerical analyses using network model are proceeded to design quantitatively the reduction method. As the air flow supplied from outside in lower stair and exhausted to outside in upper stair is formed in stairwell, the stack effect in stairwell is expected to be decreased.