• Journal of the Korean earth science society
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• v.43 no.6
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• pp.691-711
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• 2022

The state-of-the-art Earth system model as a virtual Earth is required for studies of current and future climate change or climate crises. This complex numerical model can account for almost all human activities and natural phenomena affecting the atmosphere of Earth. The Unified Model (UM) from the United Kingdom Meteorological Office (UK Met Office) is among the best Earth system models as a scientific tool for studying the atmosphere. However, owing to the expansive numerical integration cost and substantial output size required to maintain the UM, individual research groups have had to rely only on supercomputers. The limitations of computer resources, especially the computer environment being blocked from outside network connections, reduce the efficiency and effectiveness of conducting research using the model, as well as improving the component codes. Therefore, this study has presented detailed guidance for installing a new version of the UM on high-performance parallel computers (Linux clusters) owned by individual researchers, which would help researchers to easily work with the UM. The numerical integration performance of the UM on Linux clusters was also evaluated for two different model resolutions, namely N96L85 (1.875° ×1.25° with 85 vertical levels up to 85 km) and N48L70 (3.75° ×2.5° with 70 vertical levels up to 80 km). The one-month integration times using 256 cores for the AMIP and CMIP simulations of N96L85 resolution were 169 and 205 min, respectively. The one-month integration time for an N48L70 AMIP run using 252 cores was 33 min. Simulated results on 2-m surface temperature and precipitation intensity were compared with ERA5 re-analysis data. The spatial distributions of the simulated results were qualitatively compared to those of ERA5 in terms of spatial distribution, despite the quantitative differences caused by different resolutions and atmosphere-ocean coupling. In conclusion, this study has confirmed that UM can be successfully installed and used in high-performance Linux clusters.

• Journal of the Korean Society of School Health
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• v.11 no.2
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• pp.171-187
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• 1998

In recent years, adolescent issues including smoking, drinking, drug abuse, juvenile delinquency, deviant sexual behavior, mental health problems, high suicide rate, juvenile delinquency and absence without due notice, etc are emerging as serious social problems and the debate on these controversial issues is heating up. The previous studies on adolescent health behavior and social juvenile delinquency such as run-away from home and absence without due notice have been conducted mostly by cause analysis utilizing social demographic factors or biological factors. In other words, the main factors analyzed were demographic and economic factors or parent's educational level, etc, which were the fixed environmental ones that were unable to cause the change in the health behavior. Accordingly, the purpose of this study is to analyze factors which are changeable and fixable among the factors influencing the adolescent's health behavior and misconducts and, eventually influencing factors which can be used as the basis to establish health policies and health promotion program to reduce the health risk behavior and misconducts of adolescents. The study subjects were selected by dividing senior high school student in Seoul by region and through random sampling. The 890 subjects were selected from 10 schools including the preparatory school, vocational schools and institutional schools. The duration of the study was for July 1-5, 1997 for the first survey and the second one, for August 25-September 10. Regarding the analysis method, the SAS program was used. The adoptablity of theoretical model was tested through covariance structural analysis utilizing PC-LISREL 8.12 Program. The major findings of the study are as follows: As a result of establishing the model of factors influencing health behavior and juvenile delinquency, in case of male students as the health behavior self-efficacy, education level of fathers, economic level, self-control and the health interest of parent were higher, students were more likely to practice the health promoting behavior. Juvenile delinquency and health risk behavior were prevalent among those with the less shyness, the lower health behavior self-efficacy, lower self-control, lower self-assertiveness, lower economic level. The self-control was the most powerful factor. In case of female students, those with higher health behavior self-efficacy were more likely to practice the health promoting behavior whereas those with lower health behavior self-efficacy, lower self-control, lower self- assertiveness, less shyness were more likely to practice health risk behavior and juvenile delinquency. In case of prep schools, those with higher health behavior self-efficacy and better perceived health status were more likely to practice the health promoting behavior while those with less shyness, lower health behavior self-efficacy and lower academic achievement were more likely to engage in health risk behavior and juvenile delinquency. In case of vocational schools, as health behavior self-efficacy and economic level were higher, the practice rate of health promoting behavior was higher. As the self-control, shyness, self-assertiveness, health behavior self-efficacy were lower, the rate of health risk behavior and juvenile delinquency were higher. In case of social institutional schools, as, the health behavior self-efficacy, social support and economic level, health interest of parents were higher, the rate of health promoting behavior were higher. As the self-control, shyness, self-assertiveness, health behavior self-efficacy and social support were lower, the rate of health risk behavior and juvenile delinquency were higher. So the health promoting behavior was positively related to the health behavior self-efficacy, health interest of parents, social support, education level of fathers, level of perceived health status, economic level. The health risk behavior and juvenile delinquency were higher with the lower health behavior self-efficacy, self-control and self-assertiveness, lower health locus control, less shyness and loneliness, lower economic level and academic achievement. In conclusion, the health risk behavior and juvenile delinquency can be reduced by enhancing self-control, self-assertiveness, health behavior self-efficacy and social support. According to the final model drawn by connecting health behavior and juvenile delinquency, the reduction of health risk behavior can greatly contribute to decreasing social juvenile delinquency as the process of juvenile delinquency was extended from common behaviors to problem behaviors and further into juvenile delinquency.

• Health Policy and Management
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• v.8 no.2
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• pp.125-148
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• 1998

Accurate vital statistics are essential for a national health planning and evaluation. Among various vital statistics, birth and death rates, and infant and matemal mortality rates together with the causes of death are the very basic ones for above purposes as well as for the maternal and child health management. These statistics are based on the birth and death reports. It is required by law to report every birth and death within one month after its occurrence. However, in case of a neonatal death occurring prior to the birth report, most of the birth and death are not reported. Thus accurate infant and maternal mortality rates are not available yet in Korea. The main objective of this study is to develop a birth and infant death reporting system via computer network. We designed a new birth report form based on the current form and data from the analysis of medical record forms of 14 hospitals. A new form is basically addition of essential medical information to the current birth report form. Since a revision of the rules and regulations related wtih the birth report is necessary to use a new form, we kept the current from intact to make it acceptable to the government office for a field trial. We also developed computer programs for data input for birth and death reports at a medical faciltiy, data processing for production of maternal and child health indices at a health center, and management of maternal and child health services including immunization and postantal care at health center. The birth certificate and birth report can be printed out at a medical facility. The computer packages were programmed by Borland Delphi 3.0 and can be run under Windows 95 system. We proposed a new birth and death reporting system via computer network after a field trial for data input, transmission, and processing. The medical and demographic data o birth and death at medical facilities will be sent to health centers directly via computer network. The health center will retain the medical data for analysis and forward only the data for birth and death reports required by current regulations to the Dong, Up, or Myun Office. Once the birth or death is reported via computer network to the Dong Office, then the Dong Office will notify the baby's mother of the birth report and request to submit the baby's name by mail. When the baby's name its submitted. the Dong Office will forward the birth reports to the Common Court and Statistics Agency in the same way as the current system, Upon the completion of birth registration of the Common Court, the court will issue the birth certificate to mother which will be used in lieu of the family record. The advantages of proposed birth and death reporting system via computer network ar as follows ; I) The accuracy, timing, and completeness of reporting will be improved and more accurate maternal and child health indices can be obtained, ii) The maternal and child health services of health center will be obtained, iii) Epidemiologic data for pregnancy and birth can be obtained, iv) Manpower for birth and death reporting will be saved.

• Korean Journal of Environmental Biology
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• v.27 no.2
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• pp.183-190
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• 2009

Characterization of the analysis of forest vegetation, soil environmental conditions and water quality were performed from March 2003 to March 2007. The two basins were characterized by cultivated area (Kaesim reservoir) and mountain area (Jangchan reservoir), and divided into eleven small basins, where dynamics of pollutants, forest vegetation and soil environmental conditions were surveyed. The vegetation can be divided into 10 types by $Z\ddot{u}rich$-Montpellier school's method. Pearson coefficients between vegetation type and water quality were correlated with dissolved oxygen (DO) in the Quercus variabilis community at the 5% level and total phosphorus (TP) in the Larix leptolepis plantation at the 1% level. Especially total phosphorous and total nitrogen increased in small basins where the proportion of cultivated and residential area increased. The analysis of influences of pollutant discharge on water quality showed that pollutant charge was very low in forest land area ($Y_{T-P}$=-0.0017X+0.2215, r=0.16, $Y_{COD}$=- 0.0395X+8.5051 r=0.47). The soil types of western area were comparatively simple, but those of eastern area were complicated with regosols, red-yellow soils, lithosoles, etc. The pH, total solid (TS) and volatile substance (VS) of the forest and agricultural land soils collected in each site were 5.4~6.9, 75.8~80.2%, and 3.80%~5.80%, respectively. According to the analytical result of soil environmental conditions, heavy metal contents fell short to the mean value of natural conditions. Runoff amount (Y) and depth of topsoil (X) were negatively correlated, $Y_{ron}=-1.0088X_{top}+35.378$ (r=0.68). The correlation was much lower in up-stream but much higher in down-stream, because permeation into soil particle was larger on down-stream due to its more or less gentle slope. Pearson coefficients between soil pH and water pH were statistically significant at 1% level.

• Journal of Intelligence and Information Systems
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• v.21 no.3
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• pp.53-77
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• 2015

Korea has witnessed an increasing number of domestic patent applications, but a majority of them are not utilized to their maximum potential but end up becoming obsolete. According to the 2012 National Congress' Inspection of Administration, about 73% of patents possessed by universities and public-funded research institutions failed to lead to creating social values, but remain latent. One of the main problem of this issue is that patent creators such as individual researcher, university, or research institution lack abilities to commercialize their patents into viable businesses with those enterprises that are in need of them. Also, for enterprises side, it is hard to find the appropriate patents by searching keywords on all such occasions. This system proposes a patent recommendation system that can identify and recommend intellectual rights appropriate to users' interested fields among a rapidly accumulating number of patent assets in a more easy and efficient manner. The proposed system extracts core contents and technology sectors from the existing pool of patents, and combines it with secondary social knowledge, which derives from tags information created by users, in order to find the best patents recommended for users. That is to say, in an early stage where there is no accumulated tag information, the recommendation is done by utilizing content characteristics, which are identified through an analysis of key words contained in such parameters as 'Title of Invention' and 'Claim' among the various patent attributes. In order to do this, the suggested system extracts only nouns from patents and assigns a weight to each noun according to the importance of it in all patents by performing TF-IDF analysis. After that, it finds patents which have similar weights with preferred patents by a user. In this paper, this similarity is called a "Domain Similarity". Next, the suggested system extract technology sector's characteristics from patent document by analyzing the international technology classification code (International Patent Classification, IPC). Every patents have more than one IPC, and each user can attach more than one tag to the patents they like. Thus, each user has a set of IPC codes included in tagged patents. The suggested system manages this IPC set to analyze technology preference of each user and find the well-fitted patents for them. In order to do this, the suggeted system calcuates a 'Technology_Similarity' between a set of IPC codes and IPC codes contained in all other patents. After that, when the tag information of multiple users are accumulated, the system expands the recommendations in consideration of other users' social tag information relating to the patent that is tagged by a concerned user. The similarity between tag information of perferred 'patents by user and other patents are called a 'Social Simialrity' in this paper. Lastly, a 'Total Similarity' are calculated by adding these three differenent similarites and patents having the highest 'Total Similarity' are recommended to each user. The suggested system are applied to a total of 1,638 korean patents obtained from the Korea Industrial Property Rights Information Service (KIPRIS) run by the Korea Intellectual Property Office. However, since this original dataset does not include tag information, we create virtual tag information and utilized this to construct the semi-virtual dataset. The proposed recommendation algorithm was implemented with JAVA, a computer programming language, and a prototype graphic user interface was also designed for this study. As the proposed system did not have dependent variables and uses virtual data, it is impossible to verify the recommendation system with a statistical method. Therefore, the study uses a scenario test method to verify the operational feasibility and recommendation effectiveness of the system. The results of this study are expected to improve the possibility of matching promising patents with the best suitable businesses. It is assumed that users' experiential knowledge can be accumulated, managed, and utilized in the As-Is patent system, which currently only manages standardized patent information.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.36 no.3
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• pp.26-36
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• 2018

This study aims to examine the characteristics of landscape through the analysis of location and the landscape of Gugok while also conducting the empirical study through the literature review, field study, and digital analysis of the Okgung Gugok. Oksan Gugok is a set of songs set in Ogsan Creek(玉山川)or Jagyese Creek(紫溪川, 紫玉山), which flows in front of the Oksan Memorial Hall(李彦迪), which is dedicated to the Lee Eong-jeok (李彦迪). We first ascertained the location and configuration of Oksan Gogok. Second, we confirmed the accurate location of Oksan Gogok by utilizing the digital topographic map of Oksan Gogok which was submitted by Google Earth Pro and Geographic Information Center as well as the length of the longitude of the gravel measured by the Trimble Juno SB GPS. Through the study of the literature and the field investigation, The results of the study are as follows. First, Yi Eonjeok was not a direct composer of Oksan Gugok, nor did he produce "Oksan Gugokha(Music)". Lee Ia-sung(李野淳), the ninth Youngest Son of Tweo-Kye, Hwang Lee, visited the "Oksan Gugokha" in the spring of 1823(Sunjo 23), which was the 270th years after the reign of Yi Eonjeok. At this time, receiving the proposal of Ian Sung, Lee Jung-eom(李鼎儼), Lee Jung-gi(李鼎基), and Lee Jung-byeong(李鼎秉), the descendants of Ian Sung set up a song and created Oksan Gugok Music. And the Essay of Oksan Travel Companions writted by Lee Jung-gi turns out being a crucial data to describe the situation when setting up the Ok-San Gugok. Second, In the majority of cases, Gogok Forest is a forest managed by a Confucian Scholar, not run by ordinary people. The creation of "Oksan Bugok Music" can be regarded as an expression of pride that the descendants of Yi Eonjeok and Lee Hwang, and next generation of several Confucian scholars had inherited traditional Neo-Confucian. Third, Lee Jung-eom's "Oksan Donghaengki" contains a detailed description of the "Oksan Gugokha" process and the process of creating a song. Fourth, We examined the location of one to nine Oksan songs again. In particular, eight songs and nine songs were located at irregular intervals, and eight songs were identified as $36^{\circ}01^{\prime}08.60^{{\prime}{\prime}}N$, $129^{\circ}09^{\prime}31.20^{{\prime}{\prime}}E$. Referring to the ancient kingdom of Taojam, the nine-stringed Sainam was unbiased as a lower rock where the two valleys of the East West congregate. The location was estimated at $36^{\circ}01^{\prime}19.79^{{\prime}{\prime}}N$, $129^{\circ}09^{\prime}30.26^{{\prime}{\prime}}E$. Fifth, The landscape elements and landscapes presented in Lee Jung-eom's "Oksan Gugokha" were divided into form, semantic and climatic elements. As a result, Lee Jung-eom's Cho Young-gwan was able to see the ideal of mountain water and the feeling of being idle in nature as well as the sense of freedom. Sixth, After examining the appearance of the elements and the frequency of the appearance of the landscape, 'water' and 'mountain' were the absolute factors that emphasized the original curved environment at the mouth of Lee Jung-eom. Therefore, there was gugokga can gauge the fresh ideas(神仙思想)and retreat ever(隱居思想). This inherent harmony between the landscape as well as through the mulah any ideas that one with nature and meditation, Confucian tube.

• Journal of Global Scholars of Marketing Science
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• v.18 no.2
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• pp.65-88
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• 2008

Since the implementation of economic reforms in 1978, the Chinese economy grows rapidly at an average annul growth rate of 9% over the post two decades. Franchising has been widely recognized as an important source of entrepreneurial activity. Trust is important in that it facilitates relational exchanges by permits partners to transcend short-run inequities or risks to concentrate on long-term profits or gains. In the relationship between the franchisors and franchisees, trust has been described as an important source of competitive advantage. However, little research has been done on the factors affecting trust in Chinese franchisor-franchisee relationships. The purpose of this study is to investigate what factors affect the trust in the franchise system in China, and to provide guidelines and insights to franchisors which enter Chinese market. In this study, according to Morgan and Hunt (1994), trust is defined as the extending when one party has confidence in an exchange partner's reliability and integrity. We offered a conceptual model of the empirical study. The model shows that the factors affecting the trust include franchisor's supports, communication, satisfaction with previous outcome and conflict. We also suggested the franchisor's supports and communication like to enhance the franchisee's satisfaction with previous outcome, and the franchisor's supports, communication and he franchisee's satisfaction with previous outcome tend to decrease conflict. Before the formal study, a pretest involving exploratory interviews with owners from three franchisees was conducted to make sure the questionnaire was relevant and clear to the respondents. The data were collected using trained interviewers to carry out personal interviews with the aid of an unidentified, muti-page, structured questionnaire. The respondents comprised of owners, managers, and owner managers of franchisee-owned food service franchises located in Beijing, China. Even though a total of 256 potential franchises were initially contacted, the finally usable sample consisted of 125 respondents. As expected, the sampling method was successful in soliciting respondents with waried personal and firm characteristics. Self-administrated questionnaires were used for all measures. And established scales were used to measure the latent constructs in this study. The measures tapped the franchisees' perceptions of the relationship with the referent franchisor. Five-point Likert-type scales ranging from "strongly disagree" (=1) to "strongly agree" (=7) were used throughout the constructs (trust, eight items; support, five items; communication, four items; satisfaction, six items; conflict, three items). The reliability measurements traditionally employed, such as the Cronbach's alpha, were used. All the reliabilities were greater than.80. The proposed measurement model was estimated using SPSS 12.0 and AMOS 5.0 analysis package. We conducted A series of exploratory factor analyses and confirmatory factor analyses to assess the convergent validity, discriminant validity, and reliability. The results indicate reasonable overall fits between the model and the observed data. The overall fit of measurement model were $X^2$= 159.699, p=0.004, d.f. = 116, GFI =.879, NFI =.898, CFI =.969, IFI =.970, TLI =.959, RMR =.058. The results demonstrated that the data reasonably fitted the model. We also examined construct reliability and reliability and average variance extracted (AVE). The construct reliability of each construct was greater than.80 and the AVE of each construct was greater than.50. According to the analysis of Structure Equation Modeling (SEM), the results of path model indicated an adequate fit of the model: $X^2$= 142.126, p = 0.044, d.f. = 115, GFI =.892, NFI =.909, CFI =.981, IFI =.981, TLI =.974, RMR =.057. As hypothesized, the results showed that it is strategically important to establish trust in a franchise system, and the franchisor's supports, communication and satisfaction with previous outcome tend to reinforce franchisee's trust. The results also showed trust seems to decrease as the experience of conflict episodes increases. And we also noticed that franchisor's supports and communication tend to enhance the franchisee's satisfaction with previous outcome, and communication tend to decrease conflict. If the trust between the franchisor and franchisee can be established in a franchise system, franchising offers many benefits and reduces many costs. To manage a mutual trust of relationship with their franchisees, franchisor's should provide support effectively to their franchisees. Effective assistant services have direct effect on franchisees' satisfaction with previous outcome and trust in franchisor. Especially, franchise sales process, orientation, and training in the start-up period are key elements for success of the franchise system. Franchisor's support is an accumulated separate satisfaction evaluation with different kind of service provided by the franchisor. And providing support definitely can improve the trustworthy image of the franchisor. In the franchise system, conflicts of interests and exertions of different power sources are very common. The experience of conflict episodes seems to negatively relate to trust. Therefore, it is important to reduce the negative side of the relationship conflicts. Communication actually plays a broader role in reducing conflict and establish mutual trust in franchisor-franchisee relationship. And effective communication between franchisors and franchisees can improve franchisees' satisfaction toward the franchise system. As the diversification of Chinese markets, both franchisors and franchisees must keep the relevant, timely, and reliable communication. And it is very important to improve the quality of communication. Satisfaction with precious outcomes seems to positively relate to trust. Franchisors and franchisees that are highly satisfied with the previous outcomes that flow from their relationship will perceive their partner as advancing their goal achievement. Therefore, it is necessary for both franchisor and their franchisees to make the welfare of partner with effort. Little literature has focused on what factors affect the trust between franchisors and their franchisees in China. This study developed the hypotheses regarding the factors affecting trust in the transaction relationship. The results of data analysis supported the hypotheses strongly. There are certain limitations in this study. First, we may point out that some other factors missed in this study could be significantly important. Second, the context of this study, food service industry, limits its potential generalizability for all franchise systems. More studies in different categories of franchise system are needed to broaden its generalizability. Third, the model was tested empirically in a sample in Beijing, more empirical tests of the proposed model in other Chinese areas are needed. Finally, the analysis in this study was solely based on the perception of franchisees and the opinions of franchisors were not included.

• Journal of Korean Society of Forest Science
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• v.74 no.1
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• pp.47-55
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• 1986

During the past 4 years, I have made a careful analysis of the present rotating system of hunting areas, on the one hand, by asking a group of hunters to fill out a questionnaire, and on the other hand, by referring to the written documents on the subject. And, as a result, it is concluded that this system, by varying the hunting grounds each year, contains in itself several problems as follows. 1. The hunters find it quite inconvenient to use a different hunting ground year after year and they also complain that the present hunting ground charge is more than it is worth. Therefore, it is expected that the number of hunters will explosively increase in the future with the betterment of hunting conditions. 2. The hunters have almost no information about game and they are, as a whole, lacking in the ethics of hunting. 3. The allotment of time in hunting training courses is not so sufficient that it is next to impossible to improve the quality of hunters. 4. As a rule, the population density of wildlife is so sparse that it falls short of the proper standard of it. 5. The present hunting system does not seem to contribute to the advancement of tourism. 6. It is absolutely necessary to make a general survey of the situation of wildlife for the legal protection of it. Besides, the interests of hunters are so closely tied up with those of farmers and foresters that dreastic measures should be taken to settle their conflicting differences. For the purpose of solving the above-mentioned problems and at the same time, of developing sound hunting practices in the long run, I hereby make two suggestions. 1. The Establishment of the Hunting License Test System It is desirable to issue a license to a prospective hunter after he has met a special qualification and then passed a test so that he may have bits of information needed for his hunting activities. 2. The Introduction of The Revier System The fundamental concept of this system is based on the assumption that the private landowner should reserve a right to the pursuit of game and take responsibility for wildlife management.

• Journal of Hospice and Palliative Care
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• v.18 no.2
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• pp.85-96
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• 2015

In Korea, modern art therapy was developed in the 1960s and 1970s in the form of supplementary activities for patients in psychiatry. Along with the foundation of the Korean Association for Clinical Art in 1982 by psychiatric doctors, the therapy involved more various arts forms such as music, art, dance, poetry therapy, and psychodrama. More organizations with specific expertise opened such as the Korean Art Therapy Association, Korean Art Therapy Association, etc. in the 1990s and the Korea Arts Therapy Institute in 2001. As of April 2015, the members of the Korean Art Therapy Association total 15,000, including 6,200 regular members. The arts in integrative arts therapy (IAT) is an individual's creative activity which is related to his inner world, and the forms of IAT include music, drawing, dance and poetry therapy. From the aspect of phenomenology, IAT is psychophysical therapy involving the arts that helps patients recognize and perceive their experiences with an aim of at a recovery of the body and creativity from the phenomenological aspect. It is also a therapeutic activity that targets growth and development of the body and mind. Meta-analysis of the effects of art therapy with a focus on that involving music, drawing, dance movement and IAT in recent years in Korea, significant effects were observed in all factors but physical function. The biggest effect was mentality adaptation followed by activity adaptation and physiology. In the run up to the implementation of the daily flat-rate system for the health insurance reimbursement for palliative care in July 2015, the Ministry of Health and Welfare is reviewing the coverage of music therapy, drawing therapy and flower therapy, which are currently practiced by 56 hospice institutes in Korea. This is a meaningful step because the coverage of hospice and palliative care came after that of art therapy for psychiatric patients was approved in 1977. Still, there is a need clarify the therapeutic mechanism by exploring causality among the treatment media, mediation type and treatment effects. To address the issue of indiscriminately issued licenses, more efforts are needed to ensure expertise and identity of the licensed therapists through education, training and supervision.

• Information Systems Review
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• v.11 no.1
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• pp.161-179
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• 2009

Nowadays an increasing number of Internet users are running individual websites as Blog or Cyworld. As this type of personal media has a great influence on communication among people, business comes to care about Network Effect, Network Software, and Social Network. For instance, Cyworld created the web service called 'Minihompy' for individual web-logs, and acquired 2.4milion users in 2007. Although many people assumed that the popularity of Minihompy, or Blog would be a passing fad, Cyworld has improved its service, and expanded its Network with various contents. This kind of expansion reflects survival efforts from infinite competitions among ISPs (Internet Service Provider) with focus on enhancing usability to users. However, Cyworld's Network Effect is gradually diminished in these days. Both of low production cost of service vendors and the low searching/conversing costs of users combine to make ISPs hard to keep their market share sustainable. To overcome this lackluster trend, Cyworld has adopted new strategies and try to lock their users in their service. Various efforts to improve the continuance and expansion of Network effect remain unclear and uncertain. If we understand beforehand how a service would improve Network effect, and which service could bring more effect, ISPs can get substantial help in launching their new business strategy. Regardless many diverse ideas to increase their user's duration online ISPs cannot guarantee 'how the new service strategies will end up in profitability. Therefore, this research studies about Network effect of Cyworld's 'Minihompy' using System-Dynamics method which could analyze dynamic relation between users and ISPs. Furthermore, the research aims to predict changes of Network Effect based on the strategy of new service. 'Page View' and 'Duration Time' can be enhanced for the short tenn because they enhance the service functionality. However, these services cannot increase the Network in the long-run. Limitations of this research include that we predict the future merely based on the limited data. We also limit the independent variables over Network Effect only to the following two issues: Increasing the number of users and increasing the Service Functionality. Despite of some limitations, this study perhaps gives some insights to the policy makers or others facing the stiff competition in the network business.