• Journal of the Korean Institute of Gas
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• v.27 no.4
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• pp.1-11
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• 2023

The size of the OLED material market is expected to grow from $1.1 billion in 2019 to $2.3 billion in 2023, with an average annual sustainable growth of more than 19%. Among the facilities mainly used by OLED material manufacturers, accidents such as fire, explosion, and leakage frequently occur when using filtration equipment, so it is necessary to improve the risk when using filtration equipment. In this study, it was divided into four main processes, namely, assembly and disassembly process, filtration process, wet cake recovery process, and washing process in order to derive the risks associated with the use of filtration equipment. Hazard factors were derived by conducting accident case investigations, preliminary interviews, and surveys. For the analysis of questionnaire results, statistical analysis such as frequency analysis and Pearson chi-square test analysis was performed using SPSS 21, and risk improvement measures were suggested using the analyzed results. It is expected that this study will serve as a basis for dealing with safety and risk factors that may occur as the size of the OLED market expands.

• Food Science and Preservation
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• v.23 no.4
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• pp.522-529
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• 2016

Clean rice is useful to save time and labor force against washing rice in the household. Nevertheless the quality characteristics of the rice were not established well since the quality characteristics of the rice depend on types of the processing system. The aims of the current study were to understand the quality characteristics of clean rice prepared from the dry, semi-dry, and wet types of processing systems, and to suggest the appropriate processing system for production of clean rice. Here, we found that the quality of clean rice was improved with the increasing whiteness of rice by the dry type, although the whiteness of rice should be below 42 to satisfy 16.0 NTU of the turbidity for higher head rice ratio. Also, both the semi-dry and wet type systems showed higher ratio of head rice than the dry type system at below 16.0 NTU of the turbidity. These results imply that the wet type is more suitable for the place where rice is consumed fast, and the semi-dry type is more proper for long term storage of rice.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2006.06b
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• pp.221-226
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• 2006

This study is about backwash condition and membrane fouling at continuous filtration process in ballast water treatment. Displayed result that handle particle contaminant and hydrospace organism included a number of ballast that is happened in ship using automatic back washing filter. Reason that removes first contaminant that is included in number of ballast is that heighten processing effect of after processing process of the filter. Another advantage is to drop off the solids with controlling revolution of drum screen in pretreatment filtration process. The capacity of pilot plant was $10m^3/h$. The result of the test, Backwash cycle time and duration time and a signification effect on the efficiency of system and backwash Backwash duration time was determined to be fixed in 6 seconds of the system with more than 95% removal rate, It needed 1hour backwash frequency. Filtration system removal aquatic organism over $70{\mu}m$ in ballast water. This study shows that the filtration treatment system has a potential for the treatment of ballast water.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.4
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• pp.407-413
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• 2011

This paper presents an electrical power monitoring system for home energy management and an automatic appliance-identification algorithm based on the electricity-usage patterns collected during the monitoring tests. This paper also discusses the results of the field tests of which the proposed system was voluntarily deployed at 13 homes. The proposed monitoring system periodically measures the amount of power consumption of each appliance with a pre-specified time interval and effectively displays the essential information provided by the monitored data which is required users to know in order to save power consumption. Regarding the field tests of the monitoring system, the households responded that the system was useful in saving electricity and especially the electricity-usage patterns per appliances. They also considered that the predicted amount of the monthly power consumption was effective. The proposed appliance-identification algorithm uses 4 patterns: Zero-Crossing Rate(ZC), Variation of On State(VO), Slope of On State(SO) and Duty Cycle(DC), which are applied over the 2 hour interval with 25% of it on state, and it yielded 82.1% of success rate in identifying 5 kinds of appliances: refrigerator, TV, electric rice-cooker, kimchi-refrigerator and washing machine.

• Clean Technology
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• v.20 no.4
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• pp.449-456
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• 2014

There has been increasing concerns for the problems of water security in countries, caused by the frequent occurrence of localized drought due to the climate change and uncertainty of water balance. The importance of fresh water is emphasized as considerable amount of usable fresh water is utilized for power generation sector producing electricity. PV power system, the source of renewable energy, consumes water for the every steps of life cycle: manufacturing, installation, and operation. However, it uses relatively less water than the traditional energy sources such as thermal power and nuclear power sources. In this study, to find out the use of water for the entire process of PV power system from extracting raw materials to operating the system, the footprint of water in the whole process is measured to be analyzed. Measuring the result, the PV water footprint of value chain was $0.989m^3/MWh$ and the water footprint appeared higher specially in poly-Si and solar cell process. The following two reasons explain it: poly-Si process is energy-intensive process and it consumes lots of cooling water. In solar cell process, deionized water is used considerably for washing a high-efficiency crystalline silicon. It is identified that PV system is the source using less water than traditional ones, which has a critical value in saving water. In discussing the future energy policy, it is vital to introduce the concept of water footprint as a supplementary value of renewable energy.

• Journal of Environmental Health Sciences
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• v.30 no.4
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• pp.329-343
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• 2004

We conducted to investigate citizen's attitude to the treatment of food waste in Yongin city. The respondent of $41.81\%$ throws the food waste eliminate from home and store less than 1l in Yongin. When they dump the food waste, they speak out the inconvenience of damaged envelope by animals in case of home and store. This caused troubles for reason of sanitary. So a local autonomous entity must carefully consider of expand use specially designed container as like apartment house. They give an answer that the collecting time of food waste is suitable form dawn till morning. This answer shows the satisfaction of the period time to collect the food waste. They prefer to be appointed the exclusive place to collect food waste. The service interval of collect is suitable 1 time a day. They want to increase the number of washing of the collecting container. This is good method for sanitary condition, but the care of the period time to collect the food waste is more efficient than the care of the number of washing the collecting container. The care of the period time minimizes to incur the enmity of the people and to pollute in environment. The major of respondent handled the food waste after keeping the basket or a kit. This fact shows to us almost citizen doesn't feel the seriousness to remove the moisture of the food waste. Recently, many solutions which can be disposal efficiently are getting magnified and improved owing to increase utilities channel to loss in quantities and dry the food waste. We expect the reduction of food waste is solved getting easily step by step. The results of the awareness about the facility of food waste show citizen prefer recycling facility to the other facilities. If recycle facility and incineration facility are constructed, they were worried about bed smell. When some facility of the food waste is constructed, they have to maintain and to handle not to incur the enmity of the people. The spread rate of specially designed container already increased, the citizen set a high value on the use of specially designed container more than amount-rate vinyl envelope that people have used for several years. In the cost treatment about food waste, the major respondent answered the use cost of specially designed container is suitable price. So we can know the use charge is proper level. The majority of citizen more prefer autonomous plan which voluntary atmosphere creation and public information by mass media than levy system and rising treatment cost which forced plan. The citizens have pretty positive thinking of incineration, so the government needs more efforts for a public notice, which includes the incineration is no more than abandoned thing. Each of local self government has to sort the food waste and make kind of resource system related to collecting and carrying, constructing a suitable facility, proper disposal of the food waste and producing harmless in our surrounding in order to solve the invisible problems. To do above mentioned things, we have to analyze referred several problems till now. Also, to minimize the side effect, the government will have to improve through enforce the system.

• Proceedings of KOSOMES biannual meeting
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• 2006.05a
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• pp.79-83
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• 2006

Displayed result that handle particle contaminant and hydrospace organism included in number of ballast that is happened in ship using automatic bade washing filter. Reason that remove first contaminant that is included in number of ballast is that heighten processing effect of after processing process. of the filter. Another advantage is to drop off the solids with controlling revolution of drum screen in pretreatment filtration process. The fact that it is easy to attach and detach a several type of screen for getting the expected water quality is another advantage. Filter rotation speed at 1.0rpm is filter resistance 3.0bar and 3.0rpm is filter resistance 2.8bar. Filter out impurities from ballast water over 6.0rpm is filter resistance 26bar and 10rpm is filter resistance 2.5bar. Filtration system removal aquatic organism over $80{\mu}m$ in ballast water. This study shows that the filtration treatment system has a potential for the treatment of ballast water.

• Journal of Korean Society on Water Environment
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• v.31 no.5
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• pp.523-532
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• 2015

Hydrocyclone is widely used in industry, for its simple design, high capacity, low maintenance and low operational cost. The objective of this study is to develop hydrocyclone coagulation and filtration system. The system is made of hydrocyclone ballasted coagulation with polyaluminium chloride silicate (PACS) and upflow filter to treat micro particles in urban storm runoff. Roadside sediment particles (< $200{\mu}m$) was mixed with tap water to make various turbid suspensions to simulate urban storm runoff. The filter cartridge was filled with polyethylene media system and ran 1hr per everyday and total operation time were 8.19hrs and backwashing everyday after end of operation. The operation condition of flowrate was $8.2{\sim}11.9m^3/day$ (mean $10.1m^3/day$) and surface overflow rate (SOR) based on filter surface area was $45.5{\sim}65.9m^3/m^2/day$ (mean $55.7m^3/m^2/day$). The range of PACS dosage concentration was 14.0~31.5 mg/L. As the results of operation, the range of removal efficiency of turbidity, SS were 81.0~95.8% (mean 89.5%) 81.8~99.0% (mean 91.4%), respectively. An increase of filtration basin retention time brought on increased of removal efficiency of turbidity and SS, and increase of SOR brought on decreased of removal efficiency. During the first flush in urban area, storm runoff have an high concentration of SS (200~600 mg/L) and the filtration bed becomes clogged and decreased of removal efficiency. Backwashing begins when the drainage pipe valve at the filtration tank bottom is completely open (backwashing stage 1). Backwashing stage 2 was using air bubbles and water jet washing the media for 5 mins and open the drainage valve. After backwashing stage 1, 2, 61.83~64.04%, 18.53~27.51% of SS loading was discharged from filtration tank, respectively. Discharged SS loading from effluent was 7.12~14.79% and the range of residual SS loading in fliter was 2.26~5.00%. The backwashing effects for turbidity, SS were 89.5%, 91.4%, respectively. The hydrocyclone coagulation and filtration with backwashing system, which came out to solve the problems of the costly exchange filter media, and low efficiency of removing micro particles of filter type nonpoint treatment devices, is considered as an alternative system.

• Journal of the Korean Society for Railway
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• v.14 no.4
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• pp.313-319
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• 2011

In a modern society, various type of transportation modes are utilized, among them the subway system is the one of the main transportation mode which more than 7.21 million people ride a day in Seoul. Due to the increased interests on the indoor air quality (IAQ) of underground facilities, public concerns on IAQ of subway system are increasing also. Platform screen door (PSD) recently installed at the whole stations of Seoul subway and tunnel washing-out appeared to be effective in reducing particulate matters in the platform and tunnel. However there has not been any attempt to improve IAQ of subway cabin inside. Most technologies for removing airborne particulate matters are known to be difficult to adopt on the subway cabin due to the problem of maintenance cost. Therefore, the object of this study is a practical development of cabin air cleaning system which can reduce the concentration of airborne particles and harmful gases at the same time. In this paper, we focused on the development of particle removing system utilizing a roll-filter for increasing operating time of air filter. The prototype of system was designed and manufactured based on the numerical prediction results. For rollfilter device, 5 candidate filter materials were tested in point of particle collection efficiency and pressure drop. It was found that the electrically charged filter material showed the highest performance among them.

• Journal of Korean society of Dental Hygiene
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• v.9 no.2
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• pp.147-163
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• 2009

This study was attempted in order to look into 'Assist work' as to Implant system which dental hygienists perform in a clinical field. Subjects of this research were 362 dental hygienists who work at general hospital, University hospital, dental hospital, and dental clinics located in Seoul, Kyeong-gi, In-chon, and Jeon-buk area. As to research tool, we produced questionnaire which was comprised of the total 25 items regarding 3 of general features (age, career of dental hygienist, and personality), 6 of implant system assist work, 3 of Informed consent before surgery, 6 of preoperative preparation and maintenance related business, and 7 items related to postoperative maintenance. By using SPSS program, collected data was analyzed. Results of analysis in this study were as follow; 1. As to implant related education, dental hygienists' experience of education was high as 77.7%, and the people who is needed more education was 86.3%. Consequently, dental hygienists' concern about the implant related education was very high. 2. It was observed that most of informed consent making approvement by announcement to the surgical operation was made by dental hygienist before implant as 95%. 3. Over 80% of dental hygienists performed acquisition of cleanliness technology, motivation, back up articles preparation, treatment area arrangement, and etc. which we can check by preoperative maintenance items. In particular, response about the motivation was very high as more than 90%. 4. When performing an operation, in the case of disinfecting finger was low for 53.9% and the method was mainly washing with drug solution, and gown sterilization was performed only in 52.2%. Therefore education regarding disinfection was urgently needed. 5. Significance of education could be known that answers of hygienists experienced education appeared highly in items of maintenance method and there was statistically significant difference(p<0.05). 6. In case that assist work were 21cases or greater, agitation measurement was the most many performed in 68.9% and difference was showed up significantly(p<0.001). 7. Evaluation about periodontal tissue was high in dental hygienists who had experienced education and also there was statistically significant difference. In conclusion, assist work of dental hygienists was very comprehensive when implant surgery was performed, and all of items excluding hand disinfection or gown disinfection were highly showed up in most of hygienists. However, since there is the limit that we didn't investigate the quality of performing contents. It is considered that further study regarding the content has to be progressed for supporting this result in the future.