• The Journal of the Korean dental association
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• v.48 no.5
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• pp.371-378
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• 2010

The objective of this study was to compare the effectiveness of essential oil mouthrinse and interdental brush for oral hygiene in orthodontic patient. 90 patients, with fixed orthodontic appliances, were divided into 3 groups(Group 1: patients who had only used toothbrush, group 2: toothbrush + essential oil mouthrinse, group 3: toothbrush + interdental brush). Then, plaque index(PI) and gingival index(GI) were evaluated at before(T0), 3 weeks after(Tl) and 6 weeks after(T2) the experiment. The present study revealed the following conclusions: (1) There was statistically significant decrease in PI and GI of groups 2 and 3 comparing to those of group 1 during 6 weeks.(p<0.05) (2) There was no significant difference in the level of decrease in PI and GI between group 2 and group 3.(p<0.05) The present study thus implied that use of mechanical or chemical aid such as interdental brush and mouth rinse in addition to toothbrushing may help maintaining oral hygiene in patients undergoing fixed orthodontic treatment for prolonged duration.

• The Journal of the Korean dental association
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• v.55 no.2
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• pp.180-188
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• 2017

Introduction : Inadequate oral health control is a major risk of oral diseases. Regular home-based care is essential to maintain good oral hygiene. In particular, mouthrinses can support conventional tooth brushing in reducing accumulation of oral plaque. Effect : Antimicrobial mouthrinses are used as part of daily oral care to reduce plaque and gingivitis. Mouthrinses contains fluoride could help remineralization of enamel and dentin. The most common molecules contained in mouthrinses are chlorhexidine, essential oils, cetyl pyridinium chloride, triclosan, hyaluronic acid. Currently, chlorhexidine is the most efficacious compound, with both antiplaque and antibacterial activities. Similar results are reported for essential oils and cetyl pyridinium chloride, although with a somewhat reduced efficacy. Considering the adverse effects of chlorhexidine and its time-related characteristics, this molecule may best be indicated for acute/short term use, while essential oils and cetyl pyridinium chloride may be appropriate for long-term, maintenance treatment. Conclusion and suggestion : Antimicrobial mouthrinses are safe and effective, and when used in conjunction with brushing and flossing, they are an important method of reducing plaque and gingivitis. To improve compliance, dental health care professionals should adapt oral health care recommendations to fit patients' specific needs.

• Journal of Korea Multimedia Society
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• v.20 no.6
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• pp.853-864
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• 2017

HD padding area is essential redundancy in HD broadcasting. It is possible to use this padding area for the purpose of improving DTV broadcasting services. For utilization of this area, The bit of a service data was converted to black and white $8{\times}8$ block image. Converted block images are compressed with active video and are delivered to a receiver as only DC coefficients in a video stream. video quality is not effected by the proposed method, and service data was perfectly recovered in receiver without errors by using block average and threshold. The proposed utilization of HD essential padding area can possibly overcome the limited transmission stream rate with the bandwidth of HD broadcasting. If service data in transport or video stram were transferred using this padding area, it is possible to improve video quality with expanded video stream rate. Additionally, because the proposed methods are based on well-established standards, it is also useful for world-wide HD broadcasting systems such as ATSC, DVB, and IPTV.

• Journal of the Korean Home Economics Association
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• v.42 no.8
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• pp.65-76
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• 2004

The purpose of this study is to offer essential information related to early childhood education and care policy. Using the Korea Labor and Income Panel Study(KLIPS) Vol.5., this study analyzed sociodemographic factors that decide the use and type of institute for early childhood education and care. The following results are obtained： First, it is not easy for young children under three years old to use education and care institutes because of their preference for home care. Second, the mother's job status affects the child's use of child care centers and private institutes for education except for the using of early child education centers. Third, the affecting main factors for the use of child care centers are quite similar to critical factors for use of the private institute for education. Thus, young children using the private institute for education could be interpreted as coming from a low-income class compared with the children using the early child education centers.

• The Journal of Information Systems
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• v.24 no.3
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• pp.155-169
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• 2015

While information technology(IT) users' behaviors has been considered one of the most important research topics and studied in very many ways, 'non-use' has not been focused as a research topic. However, understanding non-use provides new insights for analyzing and understanding the essential nature of IT uses with wider frames and more qualitative dimension. The objective of this study is to provide some guidelines for studying non-use. For this purpose, the previous studies for non-use were reviewed focusing on resistance, suggested potential research issues and some research methodologies based on grounded theory.

• Journal of The Korean Society of Agricultural Engineers
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• v.50 no.3
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• pp.61-69
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• 2008

Land-use in northern Cheongju region is changing rapidly because of the increased interactions of human activities with the environment as population increases. Land-use change detection is considered essential for monitoring the growth of an urban complex. The analysis was undertaken mainly on the basis of the multi-temporal Landsat images (1991, 1992 and 2000) and DEM data in a post-classification analysis with GIS to map land-use distribution and to analyse factors influencing the land-use changes for Cheongju city. The area of each land-use category was also calculated for monitoring land-use changes. Land-use statistics revealed that substantial land-use changes have taken place and that the built-up areas have expanded by about $17.57km^2$ (11.47%) over the study period (1991 - 2000). This study illustrated an increasing trend of urban and barren lands areas with a decreasing trend of agricultural and forest areas. Land-use changes from one category to others have been clearly represented by the NDVI composite images, which were found suitable for delineating the development of urban areas and land use changes in northern Cheongju region. Rapid economic developments together with the increasing population were noted to be the major factors influencing rapid land use changes. Urban expansion has replaced urban and barren lands.

• Journal of Energy Engineering
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• v.5 no.1
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• pp.1-7
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• 1996

Coal consumption in Asia is projected to increase by about 1.3 billion tons over the 1993-2010 period. The expansion in coal consumption for electricity generation is the dominant factor in the large increase in coal consumption. Without effective control measures, the projected increase in coal consumption will have a serious impact on environmental effects of increased coal use in Asia. Thus, the introduction of appropriate CCTs is considered essential to achieving the twin goals of expanded use of coal decreased environmental impacts.

• Solar Energy
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• v.18 no.3
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• pp.71-80
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• 1998

In thermal energy storage system, energy collected from many types of heat source is stored in a storage tank and then supply to load for demand. Lately, practical use of thermal energy storage system and attention to essential use of energy have been increased. From this point of view, especially, a study about the energy extraction process from a storage tank is necessary. So in this study, useful rate of hot water and hot water extraction efficiency was analysed respect to dynamic and geometric parameters dominating the hot water extraction process.

• Proceedings of the Safety Management and Science Conference
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• 2004.05a
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• pp.129-136
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• 2004

Environmental factors for automotive consist of temperature, humidity, vibration(sine & random), gas, an electrical load and so on. These environmental factors are impressed in a automotive. Dependability is essential requirement in many electronic parts. Among components of automotive, the connector connecting electrical signals is one of the most important parts. Automotive -connector is inspected according to each manufacturer's test standard in which dependability should be considered. This paper aims to verify that current test standard is suitable for dependability, and present an inductive life test for automotive connector based on the field data in use-condition.

• Proceedings of the KSR Conference
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• 1998.05a
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• pp.442-449
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• 1998

Since it is essential for traction motors to reduce size and weight to achieve given traction effort, they need high input voltage. But the lack of input voltage occurs periodically due to the characteristics of train system. Therefore traction inverters use over-modulation PWM to maximize inverter's voltage gain. On the other hand, IGBT inverters can use higher frequency twice than GTO ones, which resulted in the need for novel optimal synchronous PWM strategy. This paper suggests that linearly-compensated overmodulation/optimal synchronous PWM strategy and also the simulation results of the method for a real traction motor-intertia model are presented.