• Journal of Korea Technology Innovation Society
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• v.11 no.2
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• pp.145-170
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• 2008

The existence of network is indeed the single most important factor that brings about new business phenomena in the new digital economy, especially in the IT industry. Network effect refers to a phenomenon that the increase in size of the network leads to increased network value and user utility. It determines the competitive structure of an industry and the performances of industry competitors (Shapiro and Varian, 1999). The phenomenon of increasing returns and winner-take-all enjoyed by the early winner in the competition can be attributed to the existence of positive feedback which increases the value of network and induces more users into join the network (Arthur, 1996; Shapiro and Varian, 1999; Song and Lee, 2003). This research attempts to shed light on the topic of innovation and competitive strategy of network-based industries. We analyze the case of the Korean mobile communications industry, in which a shift in technological paradigm from 2G to 3G brought new changes to the competitive structure of the industry. The Korean mobile communications industry makes an ideal case for analysis since it is an industry whose value is inherently dependent upon its user network. It is characterized by the typical increasing returns, in which a monopolizing player is enjoying firstmover's network effects. Because of the existence of network in the mobile communications industry, latecomers' disruptive innovations could not outcompete the incumbent's sustaining innovations. The contribution of this research lies in laying a groundwork for future studies by introducing a numerical simulation model to analyze the complexity theory and network effect.

• Korean Journal of Agricultural and Forest Meteorology
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• v.19 no.4
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• pp.232-245
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• 2017

In this study, the high-resolution numerical simulation results considering landuse characteristics are analyzed by using single layer Urban Canopy Model (UCM) in Weather Research Forecast (WRF). For this, the impact of urban parameters such as roughness length and anthropogenic heat in UCM is analyzed. These values are adjusted to Seoul metropolitan area in Korea. The results of assessment are verified against observation from surface and flux tower. Forecast system equipped with UCM shows an overall improvement in the simulations of meteorological parameters, especially temperature at 2 m, surface sensible and latent heat flux. Major contribution of UCM is appreciably found in urban area rather than non-urban. The non-urban area is indirectly affected. In simulated latent heat flux, applying UCM is possible to simulate the change similarly with observations on urban area. Anthropogenic heat employed in UCM shows the most realistic results in terms of temperature and surface heat flux, indicating thermodynamic treatment of UCM could enhance the skills of high resolution forecast model in urban and non-urban area.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.3
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• pp.1342-1349
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• 2013

This study was performed to investigate the factors which impact on the health-related quality of life of young-old(65-69 yr), old-old(70-79 yr), and oldest-old(80 yr or above) women in vulnerable elderly received home care service from public health centers in B city. The data were collected from 383 elderly women using structured questionnaires from September to November, 2010. Multiple regression with the SPSS WIN 18.0 program were used to analyze the data. There were statistically significant differences among young-old, old-old, and oldest-old women regarding the health-related quality of life, life satisfaction, cognitive function, frail condition. The models including life satisfaction, frail condition, cognitive function, perceived health status, number of chronic diseases were explained variance of the health-related quality of life elderly women differently like 42.8% of young-old, 28.9% of old-old, and 31.5% of oldest-old. Finally, frail condition and life satisfaction were predictors in explaining the level of health-related quality of life among vulnerable old women regardless of age. Based on the findings of the study, health promotion programs should be developed to improve health-related quality of life of vulnerable aged women according to age differences.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.4
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• pp.724-729
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• 2008

In the case of 'MAEMI', the Typhoon which formed in September, 2003, the largest-scale damage of tidal wave was caused by the co-occurrence of Typhoon surge and full tide. Until now Korea has been focusing on the calculating the amount of damage and its restoration to cope with these sea and harbor disasters. It is essential to establish some systematic counterplans to diminish such damages of large-scale tidal invasion on coastal lowlands considering the recent weather conditions of growing scale of typhoons. Therefore, the purpose of this research is to make the counterplans for prevention against disasters fulfilled effectively based on the data conducted by comparing and analyzing the accuracy between observation values and the results of estimating the greatest overflow area according to abnormal tidal levels centered on Masan area where there was the severest damage from tidal wave at that time. It's necessary utilize data like high-resolution satellite image and LiDAR(etc.) for correct analysis data considering geographical characteristics of dangerous area from the storm surge. And we must make a solution to minimize the damage by making data of dangerous section of flood into GIS Database using those data (as stated above) and drawing correcter damage function.

• Korean Journal of Social Welfare Studies
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• v.44 no.3
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• pp.237-269
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• 2013

The purposes of the study are to describe the feature of the program components, and to identify their changes in the process of designing the social work programs in the community service agencies in Korea. In order to achieve these purposes, the researchers constructed an analytical framework including 24 program components derived from the related literatures. Data was collected by questionnaires answered by the social workers who were in charge of the program development and implementation. Descriptive statistics analysis and factor analysis were applied to exam the features of the program components in 195 social service programs developed by the funds from the Community Chest of Korea and a private funding foundation. As the result of the analysis, the three noticeable features are found; (1) the agencies have very actively involved in the designing work in the process of developing practice guideline, however they have less involved in the designing work in the process of implementing program; (2) program components which are low level in design activities are intervention models, staff education, and practical ethics; (3) 8 categories of components derived from the theoretical perspective are reduced to 6 categories in the process for developing practice guidelines, finally to 4 categories in the process for implementing the programs. The implications of major findings were discussed in academic and practical perspectives in Korea, including future research works in the area.

• Review of Culture and Economy
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• v.21 no.3
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• pp.59-88
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• 2018

This study examines demand of the Korean TV VOD using monthly aggregate data and time series analysis models. In particular, the impact of box office attendance, number of IPTV subscribers, income and price of substitutes on TV VOD market is analyzed. Data on TV VOD download during the period 2013 January to 2018 June are used for the empirical analysis. TV VOD demand shows lower level of seasonality than box office attendance and the share of monthly top1 movie in TV VOD platform is also lower than that of box office attendance. The relationship between a movie's holdback and box office performance does not seem consistent. The empirical result of ARDL model reveals that in the short-run box office attendance, number of IPTV subscribers and price of substitutes have significant impact on TV VOD demand. The result on the long-term relation shows that income is the only determinant of TV VOD demand. The impact of box office attendance on TV VOD is not shown to be robust both for the short-term and long-term.

• Korean Journal of Social Welfare Studies
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• no.39
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• pp.221-252
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• 2008

The current social service delivery system for people with disabilities has four critical problems: absence of needs assessment, absence of case management, shortage of professional workers, and absence of local social welfare agencies. The Ministry of Health, Welfare, and Family of Korea has pushed forward with a project to reform the welfare infra-structure for people with disabilities since 2007. It's main purpose is to reorganize the social service delivery system for people with disabilities. A report from the project makes two suggestions: introduction of new standards for disability and set-up of disability service determination centers. The new standards for disability are suggested to include a work ability test and a welfare needs assessment tool as well as a medical standard. Three models for disability service determination centers are suggested: independent model, local governmental model, and public corporational model. Tentative operations using the three models are on the way in the second half of 2008. In order to reform the social service delivery system for people with disabilities, this study makes a fundamental suggestion: set-up of about 120 local welfare agencies over which the Ministry of Health, Welfare, and Family can have direct control, and which are equipped with professional workers who are able to perform needs assessment and case management. In actuality, welfare centers for disabled people are the best options for local welfare agencies for disabled people.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.258-258
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• 2019

계산 격자에 기반하여 천수 흐름을 모의할 때, 그 격자에 담긴 물의 양을 정확하게 파악할 필요가 있다. 예를 들어, 초기조건으로 수위가 부여된다면 계산격자의 기하 특성에 맞추어 흐름 변수인 수심이나 흐름 단면적으로 바꾸어야하기 때문이다. 필요에 따라서는 모의 결과를 수위로 보이거나 격자 속 수심을 계산에 사용할 수도 있으므로 그 역변환도 고려되어야 한다. 2차원의 삼각형 계산격자에 대해서는 물의 부피와 수위 관계(volume/free-surface relationship)가 이미 정확(exact)하게 구명되어 있다(Hwang, 2017, J. KWRA). 그런데 1차원 문제의 횡단면에서 흐름 단면적과 수위의 관계(area/free-surface relationship)는 수위로부터 면적 환산에 대해서는 정확하나 그 역변환은 그렇지 않다. 매 시간 단계에서 갱신된 흐름 단면적으로부터 수위를 환산하기 위해 미리 작성된 면적-수위 자료를 이용한 선형 보간이 적용된다(Goodell, 2011, The RAS Solution). 이때, 환산 정확도는 자료의 해상도에 의존된다. 다행히 하천 횡단면 대부분을 채워 흐르는 홍수모의에서는 이 문제가 그리 심각하지는 않다. 심지어 수위가 복단면 저수로 턱에 걸쳐있어 흐름단면적이 급변하는 경우에도 환산 수위의 정확도는 크게 훼손되지 않는다. 그러나 미미한 환산 오차일지라도 그로 인해 수위가 저수로 턱을 넘거나 그보다 작을 수 있다. 이 경우, 홍수터의 잠김여부에 따라 수면폭(top width)이 실제 계산 결과에 비해 크게 달라질 수밖에 없다. 수면폭 오차는 그것을 이용하여 결정되는 수리 수심(hydraulic depth)이나 평균 하상고(mean bed level)의 산정에도 전파된다. 이 연구에서는 하천 횡단면에서 수위와 흐름 단면적 사이의 환산 정확도를 크게 높일 수 있는 기법을 제시하였다. 먼저 하천 횡단면에서 주어진 수위에 대해 흐름 단면적을 산정할 수 있는 알고리듬을 보였다. 또한, 횡단면에서 수위와 흐름 단면적의 관계가 단조 증가 함수(monotonically increasing function)임에 착안하여 그 역변환에 대해 해 찾기(root finding) 방법의 하나인 Brent 기법을 적용하였다. 이 기법은 주어진 구간에서 도함수가 알려져 있지 않은 경우에 대해서도 효과적으로 해를 찾을 수 있는 것으로 알려져 있다(Press et al., 2002, Numerical Recipes in C, 2nd Ed.). 내성천 하류 수계의 333개 단면에서 수면폭에 대한 상대 오차를 살펴보면, 선형 보간에 의한 기존 방법으로는 면적-수위 자료의 수가 1,000개가 되어도 그 최대치가 1% 이내에 들지 않은 반면, 이 연구에서 제시한 기법으로 면적-수위 자료 없이도 1% 이내로 줄어드는 것을 확인하였다. 다만, 반복 계산에 의한 계산 시간의 증대를 피할 수 없다. 미리 작성된 면적-수위 자료를 이용하면 계산 비용을 줄일 수 있으며, 약 35개의 구간으로 나누었을 때 비용 대비오차가 적절하였다. 이 연구는 한국건설기술연구원(주요사업 과제번호: 20190116-001)의 지원에 의한 것이다.

• Journal of Service Research and Studies
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• v.8 no.3
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• pp.115-136
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• 2018

Recently R&D projects take a collaborative works which involve industries, research institutions, and academic fields together. Collaborative R&D enjoys the economy of scales and economic efficiencies in that costs and risks share each others and compensate their competences. But there are some problems. The imbalance of power, the asymmetry of information, loss of trust, and opportunism among the co-researchers make the collaborative R&D difficult to succeed and disappointed outcomes. There are many variables on explaining the interorganizational relationships. Among them, I choose some relevant variables, construct research model and some hypotheses. Independent variables are fairness and quality, and dependent variables is loyalty. And trust are treated as the intervening variable between the independent variables and dependent variable. To test the research model and some hypothesis empirically, I collected the data using the questionnaire, The questionnaire was distributed to the persons that do collaborative R&D in Daeduck Innopolis. Sample size was 448, it was enough to analyze statistically. Data were analysed using the SPSS and AMOS. Procedural fairness and distributive fairness affect the organizational trust positively, and procedural fairness and distributive fairness affect member trust positively. Procedural quality and outcome quality affect the organizational quality positively. Procedural quality affects the member trust positively, but outcome quality does not affect member trust. Procedural fairness and distributive fairness does not affect the loyalty positively. Procedural quality does not affects loyalty, but outcome quality affects the loyalty positively. The organizational trust affects loyalty positively, and member quality affect loyalty positively.

• Korean Journal of Environment and Ecology
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• v.33 no.3
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• pp.366-374
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• 2019

This study aims to analyze the characteristics of ventilation corridor and propose its utilization strategies in Jeonju city in order to discuss how to utilize urban ventilation corridors as a planning factor for reducing heat wave impact and fine particle pollution. For these purposes, cold air characteristics such as cold air flow and height of cold air in Jeonju area located in the Honam Jeongmaek were analyzed and major ventilation corridors were specified. Based on them, we proposed mountain management strategies for securing and utilizing ventilation corridors. We used KALM (Kaltluftabflussmodell), a cold air simulation model developed in Germany and identified both the cold air flow and the height of cold air layer generated during 6 hours at night. As a result, the cold air flow generated in the forests located in the northeast and east sides of the Jeonju city became clear and the height of cold air layer increased in the valley terrain and farmland areas with time. In particular, Jeonju City has an ideal structure of urban ventilation corridor. Based on the results, the area where the cold air generation is active was designated as the 'cold air conservation area', and the area requiring the management for the good cold air flow was as the 'cold air management area'. This study is expected to be used as basic data of policy making and research for reducing heat wave impact and fine particle pollution such as climate change adaptation policy and urban forest plans for ventilation corridor composition.