• Journal of Environmental Health Sciences
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• v.49 no.4
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• pp.183-189
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• 2023

Background: The indoor air quality of classrooms, in which the capacity per unit area is high and students spend time together, must be managed for safety and comfort. It is necessary to develop an eco-friendly indoor air quality reduction method rather than biased management that relies solely on air purifiers. Objectives: In this study, plants and air purifiers were installed in middle school classrooms to evaluate the indoor PM_2.5 reduction. Methods: Four middle school classrooms were selected as test beds. Air quality was monitored in real-time every one minute using IoT equipment installed in the classrooms, corridors, and rooftops. After measuring the background concentration, plants and air purifiers were installed in the classroom and the PM_2.5 reduction effect was analyzed through continuous monitoring. Results: After installing the plants and air purifiers, the average PM_2.5 concentration was 33.7 ㎍/m³ in the classrooms without plants and air purifiers, 25.6 ㎍/m³ in classrooms with plants only, and 21.7 ㎍/m³ in classrooms with air purifiers only. In the classroom where plants and air purifiers were installed together, it was 20.0 ㎍/m³. The reduction rates before and after installation were 4.5% for classrooms with plants only, 16.5% for classrooms with air purifiers only, and 27.6% for classrooms with both plants and air purifiers. The I/O ratio, which compares the concentration of PM_2.5 in classrooms with corridors and outside air, also showed the lowest in the order of plants and air purifiers, air purifiers, and plant-only classrooms. Conclusions: The PM_2.5 reduction effect of using plants was confirmed, and it is expected to be used as basic data for the development of environmentally-friendly indoor air quality improvement methods.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.4
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• pp.353-368
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• 2013

All Koreans had suffered heavily from municipal and industrial air pollution problems since 1960's to 1980's. However the levels of $SO_2$, CO, and Pb have been dramatically decreased since 1990's due to various air pollutants' reduction policies under the provisions of the 1978 Environmental Preservation Act and the 1990 Air Quality Preservation Act such as increasing the supply of low-sulfur fuel, the use of cleaner fuel, no use of solid fuel, and so on. Even though the national ambient air quality standard has been strengthened to protect public health and welfare, the levels of $NO_2$, $O_3$, and $PM_{10}$ frequently exceed the corresponding standards; for example, only 4 stations (1.7%) out of 239 nationwide monitoring stations satisfied the 24-hr based PM10 standard in 2011. Moreover, upto the present time, since there are serious underlying policies of economism and growth-first which can not be solely solved by the environmental laws, it is difficult to root out undesirable social evils such as public indifference, passive academic activities, complacent government bureaucracy, insufficient social responsibility of enterprise, and radical activities of environmental groups. The paper initially reviewed air pollution history of Korea with surveying various environmental factors affecting in/out-door air pollution in the past Korea. Further this study extensively investigated legal and political changes on air pollution control and management for the last 50 years, and then intensively discussed the present environment-related laws and policies unreasonably enforced in Korea. It is necessary to practically revise many outdated legal policies based on health-oriented thinking and on our current economic levels as well.

• Journal of Korean Society for Quality Management
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• v.14 no.1
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• pp.39-46
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• 1986

This paper considers two sided tests for exponential null distribution against NBUE or NWUE alternative in life testing. The main results concern the strong consistency of two proposed statistics, one being similar to Kolmogorov - Smirnov statistic, the other similar to Cramer-Von Mises statistic. Also obtained are the asymtotic null distribution and the exact Bahadur slope of the statistic similar to Kolmogorov-Smirnov.

• Proceedings of the Korean Society for Quality Management Conference
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• 2009.10a
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• pp.230-233
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• 2009

Remanufacturing is an industrial manufacturing process. The merits of manufacturing are to reuse old products to perform like a new product and to save energy, natural resources, landfill space and to reduce air pollution by less re-smelting. This paper proposes a systemic approach for activating the domestic remanufacturing industry. The approach is based on inside and outside regulations to apply remanufacturing companies. And, we analyzed the state and problems of remanufacturing industry for automobile parts.

• Journal of Korean Society for Quality Management
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• v.20 no.2
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• pp.67-75
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• 1992

In this paper we propose a class of tests for the parallelism of two regression lines based on linear placement statistics. The results of a small-sample Monte Carlo study show that the proposed tests are reasonably good in level control and powers.

• Journal of Distribution Science
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• v.18 no.10
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• pp.39-52
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• 2020

Purpose: This study aims to find out the relationship between the impact of Korean crew on airline service quality in the global aviation market, which is the representative of the face-to-face sales and can help in the face-to-face market of aviation services. Research design, data: The survey was conducted for about a month from March 1 to April 6, 2020, and a total of 300 copies were used in the analysis of the results. To verify the hypothesis, data was analyzed using the statistical package program SPSS 18.0, and frequency analysis, exploratory factor analysis, correlation analysis, and multiple regression analysis were performed. Results: It is a study on the sales of face-to-face service of crews of global airlines. Non-verbal elements in airline service face-to-face sales have been shown to have a significant impact on service quality. Conclusions: In the face-to-face service sales of global airlines, communication has been shown to affect service quality. A face-to-face sale using mother tongue means important. The better the flight attendant's linguistic face-to-face selling ability, the more positive on the airline's quality of service. It suggests that the communication skills of managers in the aviation service market are important for repurchase.

• Journal of Korean Society for Atmospheric Environment
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• v.25 no.5
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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.

• Journal of Korean Society for Atmospheric Environment
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• v.34 no.2
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• pp.294-305
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• 2018

Quantitative assessment on the impact from North Korean emissions to surface particulate matter(PM) concentration in the Seoul Metropolitan Area (SMA), South Korea is conducted using a 3-dimensional chemistry transport model. Transboundary transport of air pollutants and their precursors are important to understand regional air quality in East Asian countries. As North Korea locates in the middle of main transport pathways of Chinese pollutants, quantifiable estimation of its impact is essential for policy making in South Korean air quality management. In this study, the Community Multiscale Air Quality Modeling System is utilized to simulate regional air quality and its sensitivity, using the Comprehensive Regional Emissions inventory for Atmospheric Transport Experiment 2015 and the Clean Air Policy Support System 2013 emissions inventories for North and South Korea, respectively. Contributions were estimated by a brute force method, perturbing 50% of North and South Korean emissions. Simulations demonstrate that North Korean emissions contribute $3.89{\mu}g/m^3$ of annual surface PM concentrations in the SMA, which accounts 14.7% of the region's average. Impacts are dominant in nitrate and organic carbon (OC) concentrations, attributing almost 40% of SMA OC concentration during January and February. Clear seasonal variations are also found in North Korean emissions contribution to South Korea (and vice versa) due to seasonal characteristics of synoptic weather, especially by the change of seasonal flow patterns.

• Proceedings of the Korean Society for Quality Management Conference
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• 2007.04a
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• pp.356-358
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• 2007

There are some kinds of greenfield in city. Greenfield is very important about cleaning air pollution. A green field is consist of street-trees, parks, river etc. Plants of greenfield normally take in carbon dioxide and exchange it for oxygen and water vapor; it now appears that plants can also take in other, more dangerous gases, through the tiny openings, or stomates, on their leaves. It is calculated the quantity of taking $CO_{2}$, and emission of $O_{2}$ and We analyse the economic effect about that in this paper.

• Journal of Korean Society for Quality Management
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• v.24 no.4
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• pp.141-155
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• 1996

In service industries, it is very hard to transform the quantified factor into qualified one. Nowadays, however, service industries employee various methods developed by the academic society to manage effectively. Therefore, we have focused our research on QFD that is applied to improve the flow of execution in customer complains in Air Lines which can be considered as the representation of Service Industries. QFD is a method of developing new service with response to the demand from customer thanks to the application of QFD. In this paper we decide the priority of the department for executing the customer service of Air Lines. After setting up the relations among departments, we analyze the problems caused by the contact between customers and departments.