• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.3
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• pp.586-597
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• 2004

MAC (Medium Access Control) protocol is necessary for a OLT (Optical Line Termination) to allocate bandwidth to ONUs (Optical Network Units) dynamically in ATM PON (Passive Optical Network) operated in a kind of optical subscriber network having tree topology. The OLT collect information about ONUs and provide all permission with each ONU effectively by means of MAC protocol. Major functions of MAC protocol are composed of the algorism for distributing permission demanded by a ONU dynamically and allocation all permission used in APON properly. Sometimes MAC get to be a element of limiting the whole operation speed and occupy a most frequent operation part of the TC (Transmission Convergence) function module so it have to be designed to guarantee the best quality for each traffic. This paper introduce the way of implementation of a algorism which satisfy all of the upper renditions. This MAC algorism allocate bandwidth according to a number of working ONU and the information of the queue length dynamically and distribute permission for same interval to minimize delay variation of each ONU cell. MAC scheduler for the dynamic bandwidth allocation which is introduced in this paper has look-up table structure that makes programming possible. This structure is very suitable for implementation and operated in high speed because it require very simple and small chip size.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.1
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• pp.36-46
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• 2011

The purpose of this study was to manufacture colored Hanji for interior materials by combining color therapy and natural dyeing. To manufacture colored Changhoji for interior materials, seven species of dyestuff were selected as a results of preliminary natural dyeing. As mordants, 0.5% $AlK(SO_4)_2{\cdot}12H_20$ and 0.5% $Cu(CH_3COO)_2{\cdot}H_2O$ solution were used respectively. To estimate natural dyeing properties of Changhoji, the value of $L^*,\;a^*,\;b^*$ and Munsell HV/C were measured by spectrophotometer. The super eight colors produced as follows; red from safflower, orang from goldthread and gardenia, yellow from turmeric, green and turquoise from indigo and pagoda tree flower, violet and magenta from sappanwood, and blue from indigo.

• Parasites, Hosts and Diseases
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• v.44 no.2 s.138
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• pp.133-138
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• 2006

This experiment was undertaken to screen the acaricidal effects of herb essential oils (pennyroyal, ylang ylang, citronella, lemon grass, tea tree, and rosemary) at different doses (0.1, 0.05, 0.025, 0.0125, and $0.00625{\mu}l/cm2$) and exposure times (5, 10, 20, 20, 30 and 60 min) on house dust mites Dermatophgoides farinae and D. pteronyssinus. The most effective acaricidal components of pennyroyal (Mentha pulegium) were analyzed using a gas chromatography-mass spectrometer (GC-MS). Of these essential oils, the most effective was pennyroyal, which is composed essentially of pulegone (> 99%), at a dose of $0.025{\mu}l/cm^2$, which at an exposure time of 5 min killed more than 98% of house dust mites. In the pennyroyal fumigation test, the closed method was more effective than the open method and maximum acaricidal effect was 100% at $0.025{\mu}l/cm^2$, 60 min. The results show that herb essential oils, in particular, pennyroyal was proved to have potent acaricidal activity.

• Asian Journal of Turfgrass Science
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• v.19 no.1
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• pp.27-38
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• 2005

This study was conducted to find out withering and dying trends of turfgrasses on the base of tree, and to investigated how much area of turfgrasses withering and dying were progressed on angle of inclination at golf course. Turfgrasses withering and dying on base of trees on slope was extended more to the down-solpe direction than to the up-solpe direction. This trend was common in all experiment plot. Turfgrasses on the base of trees were withered and dead by competing with tree root fur nutrients and moisture in soil. But the trend of the withering and dying in some experiment plots occurred by soil erosion following turfgrass withering and dying occurring on upside ridge. This trend was generally appeared in region of tree community at upside ridge. The form of turfgrass withering and dying on the base of tree in some experiment plots was similar to that of the tree crown. This withering and dying from occurred at the $11^{th}$ experiment plot in Ji San Golf Course and the $6^{th}$ experiment plot in East valley Golf Course.

• Journal of the Korean association of regional geographers
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• v.3 no.1
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• pp.155-163
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• 1997

The Mongolian ger is ideally suited to the mongol's steppe climate and the nomadic way of life. This is a multipurpose dwelling which can be easily collapsed, transported to another place and put up again fully preserving its original shape. The pastoral nomadic ger has two key components: the wooden framework and the felt cover. The wooden parts are the walls(khana), the long poles(un), the smoke escape(toono) and its supports(bagana). One wall consists of 10-15 branches of willow tree. each about 1.5m high bound together in a way making it possible to fold it for transportation and then unfold it like an accordion. The unfolded walls are connected to form a circle. The long poles(un) are fastened to the upper part of the walls, with the other end passed through the toono hole, the only sky window and smoke escape through it from the ger. The toono is propped up by two posts, called bagana. All this forms the wooden framework of the ger, which is covered with felt. When the herders fire up their metal stoves, the temperature inside the ger becomes quite comfortable. Because the nomads live in a climate where there is only one growing season in a year, they do not make long migrations to new pastures. Livestock subsist on standing vegetation for eight months of the year. The basic pasture migration strategy is to leave enough standing vegetation at the end of the growing season in September to suffice until the new growth appears the following May. Mongolians use a type of compressed tea leaf that is called "brick" tea in English because it is rock solid and roughly the shape of a brick. And they consume a larger percent(88%) of fat from animal products such as meat, milk, butter, and cheese than any other people in the world. Milk products made from the milk of sheep, yak, and goats are major foods in the nomad's diet, but they are produced mainly in summer when all the animals are lactating. Mongolians made their special nomadic food culture on the steppe.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.6 s.348
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• pp.9-22
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• 2006

When the legacy multicast routing protocols are adopted in If-based mobile core networks, there are some problems such as traffic injection from unnecessary sources, traffic overhead by group management and router performance degradation by large amount of multicast session information. In this paper, we propose a stateless multicast mechanism which has no need to maintain multicast information for session status and reduces redundant network overhead for maintaining multicast tree. In addition interworking with IGMPv3 gets rid of traffic from unnecessary sources which have no registration from receivers. The operations of essential components including a gateway node for interworking with the legacy Internet multicast network, a gateway node for transparency to radio access network and a intermediate node in mobile core networks, are definitely defined and the proposed communication architecture is completed. Finally we evaluate and approve the performance of the proposed architecture by means of well-designed network simulation.

• Journal of the Korean Applied Science and Technology
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• v.31 no.2
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• pp.285-295
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• 2014

Citrus essential oil were extracted from citron peel of cultivated in Gohong (CCP) using environmentally friendly supercritical carbon dioxide method. Antioxidant activity and aroma composition of the essential oils extracted by the SC-$CO_2$ method were evaluated by comparing with those extracted by organic solvent method. Fatty acid composition, DPPH scavenging, and antioxidant activity of the oils obtained by different extraction condition of SC-$CO_2$ method were investigated and their antioxidant activities were compared with commercially available lavender, eucalyptus and tea tree oils. As the results, linoleic acid was most abundantly found from CCP oil extracted by the SC-$CO_2$ method and cis-11,144-eicosadienoic acids was second abundantly found. Radical scavenging ability of DPPH was 98% when the concentration of CCP oil was 50 mg/mL. This scavenging ability increased with the increase of oil concentration. On the other hand, flavonoids content (84 mg/100g) of the CCP oil extracted by the SC-$CO_2$ method was slightly higher than that (75 mg/100g) by hexane extraction. The results, obtained from CCP oil by GC-MS, indicated that, among 66 components, the content of terpenes was 55.8% and limonene was 27.3%.

• Journal of Korean Academy of Nursing
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• v.29 no.6
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• pp.1284-1293
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• 1999

This study was designed to investigate the effect of aromatherapy on skin xerosis and pruritus in patients undergoing maintenance hemodialysis. Twenty one subjects of this study were selected from St. Paul's Hosipital in Seoul. All the subjects were received the mineral oil massage at the arm without fistular three timesper week for 4 weeks. After 2 weeks period of wash-out, the subjects were received the aromatherapy of lavender and tea tree essence oil in the same way. This study was carried out from March 20 to June 13, 1998. Pruritus score, skin pH and stratum corneum hydration were measured before and after each treatment. But, biochemical parameters were measured before the treatment of the mineral oil massage, after the treatment of the mineral oil massage and the aromatherapy. Data of this study were analyzed by paired t-test, repeated measures ANOVA, Bonferroni multiple comparisons and Pearson correlation coefficient. The results were as follows ; 1. Pruritus score was significantly decreased after the aromatherapy, while no significant change after the treatment of the mineral oil massage. Therefore, there was a significant difference in the priritus score between the two treatments. 2. Stratum corneum hydration was significantly increased after the aromatherapy, while no significant change after the treatment of the mineral oil massage. Therefore, there was a significant difference in the stratum corneum hydration between the two treatments. 3. Skin pH was significantly increased after the treatment of the mineral oil massage, while no significant change after the aromatherapy. Therefore, there was no significant difference in the skin pH between the two treatments.4. After the aromatherapy, the serum calcium was significantly increased. Whereas the serum parathyroid hormone intact was significantly decreased compared with the treatment of the mineral oil massage. But the level of the serum Ca and PTH-intact were within the normal range. 5. Stratum corneum hydration was decreased corresponding to the duration of hemodialysis, while pruritus score and skin pH showed no change corresponding to the duration of hemodialysis and the age of the subjects. The correlation of pruritus score on skin pH, stratum corneum hydration and biochemical parameters was not significant. In conclusion, this findings indicate that aromatherapy may be effective in decreasing skin xerosis and pruritus score in uremic pruritus patients undergoing maintenance hemodialysis.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.32 no.2 s.57
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• pp.99-103
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• 2006

Natural essential oils showed anti-microbial activity on relatively broad spectrum of bacterial and fungal species. These materials had much more intensive anti-microbial activities than synthetic preservatives on C. albicans, A niger, and P. acnes, especially. In the experimental group, anti-microbial activity was order of tea tree oil (from Melaleuca alternifolia) > methylparaben > phytoncide (from Chamaecyparis obtusa). Also, natural essential oils had anti-oxidative and anti-inflammatory effects. These results suggest that natural essential oils can be useful as good cosmetic ingredients such as natural preservatives and anti-oxidants.

• The korean journal of orthodontics
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• v.39 no.3
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• pp.177-184
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• 2009

Objective: The aim of this study was to investigate the occurrence rate of bacteremia following toothbrushing with toothpastes composed of several antibacterial agents and compare the results with the conventional oral hygiene maintaining methods in orthodontic patients. Methods: This clinical study included 100 adult orthodontic patients who were divided into 4 groups. Each group comprised of 25 patients, wearing fixed orthodontic appliances. In the first group, bacteremia was assessed after toothbrushing without using any toothpaste. In the second group, a 0.2% chlorhexidine gluconate mouthrinse was used before brushing with no toothpaste. In the third group, subjects brushed with a commonly used toothpaste which did not include an additional antimicrobial agent. The fourth experimental group used toothpaste which included tea tree oil, clove oil, peppermint oil and bisabolol as antimicrobial elements. Pre- and post-brushing blood samples were obtained using a strict aseptic technique. All samples were microbiologically evaluated using blood culture bottles. Results: Toothbrushing in orthodontic patients yielded to an increase in the occurrence rate of bacteremia when using normal toothpaste or no toothpaste at all. Conclusions: The use of chlorhexidine mouthwash before toothbrushing, and brushing with antimicrobial toothpaste did not show a statistically significant difference in preventing the occurrence of bacteremia (p > 0.05).