• Journal of KIISE:Information Networking
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• v.30 no.3
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• pp.329-342
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• 2003

Most of the existing multicast routing protocols for ad-hoc networks do not take into account the efficiency of the protocol for the cases when there are large number of sources in the multicast group, resulting in either large overhead or poor data delivery ratio when the number of sources is large. In this paper, we propose a multicast routing protocol for ad-hoc networks, which particularly considers the scalability of the protocol in terms of the number of sources in the multicast groups. The proposed protocol designates a set of sources as the core sources. Each core source is a root of each tree that reaches all the destinations of the multicast group. The union of these trees constitutes the data delivery mesh, and each of the non-core sources finds the nearest core source in order to delegate its data delivery. For the efficient operation of the proposed protocol, it is important to have an appropriate number of core sources. Having too many of the core sources incurs excessive control and data packet overhead, whereas having too little of them results in a vulnerable and overloaded data delivery mesh. The data delivery mesh is optimally reconfigured through the periodic control message flooding from the core sources, whereas the connectivity of the mesh is maintained by a persistent local mesh recovery mechanism. The simulation results show that the proposed protocol achieves an efficient multicast communication with high data delivery ratio and low communication overhead compared with the other existing multicast routing protocols when there are multiple sources in the multicast group.

• Journal of agricultural medicine and community health
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• v.25 no.2
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• pp.245-263
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• 2000

This study was conducted to provide the basic data about the health effects of pesticide exposure among farmers for agricultural health study. We analyzed 412 self-administered questionnaires collected from the male farmers who spray pesticides in Kyoung-ju area, Korea. Survey questions were about chronic symptoms, acute symptoms while pesticide spraying, pesticide intoxication accident, safety rules, protective equipments etc. The correlations among the variables related to pesticide exposure and the factors in acute pesticide poisoning and chronic symptoms of farmers were also analyzed. For chronic symptoms, the prevalence of 'tiredness and languor', 'lumbago', 'nocturia', 'shoulder pain', 'numbness', and, for acute symptoms while pesticide spraying, the experience rate of 'itching sense of skin', 'dizziness/headache', 'fatigue', 'eye glaring' were high compared with other symptoms. For 'experience of intoxication accident by pesticide in family', 7.1% of the subjects experienced the accident and the causes were pesticide spraying, food contamination by pesticide, suicide etc. Among safety rules, 'take a bath after spraying', 'change clothes after spraying' were kept relatively well, and, for protective equipments, hat, boots, mask, gloves, protective clothes(lower) were put on relatively well. The factors associated with acute pesticide poisoning were the extent of keeping safety rules, spraying time, orchard cultivation, agricultural area and spraying days per year etc. And the factors associated with chronic symptoms were acute symptoms while pesticide spraying, agricultural area, farming career, extent of keeping safety rules, extent of agricultural work and the pesticide exposure index etc. From these results, it is suggested that to reduce the health effects by pesticide exposure among farmers, the education to promote to keep safety rules and wear protective equipments, and information services should be recommended. And further studies on the long term health effects of pesticide exposure among farmers are required.

• Korean Journal of Heritage: History & Science
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• v.51 no.4
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• pp.66-83
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• 2018

This article focuses how the materials of hatstrings of the 19th to 20th century gat, the Korean top hat for men among the collections of National Folk Museum of Korea, was transformed after port opening treaties with overseas since 1876. As a result of analyzing the materials of the hatstrings, amber, tortoiseshell, wood and bamboo as the traditional materials were used, and ivory, glass (soda glass, lead glass, alkali mixed glass) and plastics (cellulose nitrate, phenol-formaldehyde, polystyrene, acryl) were newly used for the hatstrings. Bamboo, wood and amber were the most frequently used materials. Bamboo was mainly used for the pipe of hatstring and were combined with beads and central decorations of other materials. This shows the trend of bamboo hatstring according to the simplification of the clothing and the culture by Regent Heungseon Daewongun. Ambers were used in the central decorations and beads and the origin of ambers was baltic amber just like the amber relics found in Korea. Compositions of glass were soda glass and alkali mixed glass which were excavated or handed down in Korea from ancient times to Joseon dynasty. But in the case of lead glass, Na2O was detected and it is considered to be a new type lead glass for crafts which came from overseas after port opening since 1876 because it showed the characteristic that it deviates from the lead glass component found in Korea. Plastics such as cellulose nitrate and phenol-formaldehyde were used as new synthetic materials to replace traditional materials such as tortoiseshell, amber, and coral as in the West. Cracks, crazing, crumbly and yellowing of cellulose nitrate of hatstrings were observed by deterioration. The survey of the materials of the 19th to 20th century hatstrings among the collections of National Folk Museum of Korea showed that the introduction of new materials such as glass and plastics were used to replace natural materials such as tortoiseshell and amber along with the use of traditional materials after port opening since 1876.

• (The)Study of the Eastern Classic
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• no.49
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• pp.393-430
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• 2012

In this paper, Bowen's family therapy from the perspective of the theory, narrative analysis of Korean novels, three Regis - tration Subsection.Bowen's description of the individual's behavior is causing problems within the family of anxiety and self-differentiation using two variables. The home if problems or conflicts expressed in these works, the figures showed that the undifferentiated ego at the center of the problem. Undifferentiated ego character felt extreme anxiety when their alienation from the relationship of the family-oriented jeokjangja Undifferentiated ego to relieve anxiety and to consolidate their position in the family relationship, so people were strongly united with each other. Sohyunseongnok, Chossisamdaerok series structures and patterns of a series of domestic problems occur, "mother and son, self-differentiation self undifferentiated undifferentiated ego and self-differentiation mother son, mother and self-ego undifferentiated undifferentiatedcan be subdivided into the son '.Established a symbiotic relationship between them and the U.S. established the presence of a pattern, healer, depending on the deployment method depends narrative. And is divided accordingly, self-determination and to the Son, a son, a son to be born again through repentance of the execution. Depending on the presence or absence healer than what was described on the deployment structure differs. Undifferentiated ego and self undifferentiated mother son family therapist within the family, the problem is solved. Son, a son to repent and be born again, and that caused the problem. Ego Undifferentiated mother and son self-differentiation, undifferentiated ego and self-differentiation mother son home my healer in the absence son committed suicide and executions each tragedy occurred. Personal level, but occurred at home conflicts or problems about this when analyzing the Three-generation stories of the Joseon Dynasty, by applying the theory of Bowen's Family Therapy view dimension in the relationship between family were. Toughness or desire of any one individual, but serious conflicts and problems within the family, the institution of the family itself is the root cause was. And was able to reveal aspects of narrative flow, depending on the presence or absence of family therapists vary significantly depending on his role in the rest of the family comfort and peace determines whether the Three-generation stories of the Joseon Dynasty, received an important narrative of men and axis formation. In a gauze-like situation of this problem in the Three-generation stories of the Joseon Dynasty, a personal desire or toughness in confined without the dimension of the entire family. And extrinsic psychological approach against the background of the wall in the main narrative of the sufferings of women of Korean novels, approached significance.