• Title/Summary/Keyword: 구조모형 추정

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Application of Artificial Neural Network to Improve Quantitative Precipitation Forecasts of Meso-scale Numerical Weather Prediction (중규모수치예보자료의 정량적 강수추정량 개선을 위한 인공신경망기법)

  • Kang, Boo-Sik;Lee, Bong-Ki
    • Journal of Korea Water Resources Association
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    • v.44 no.2
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    • pp.97-107
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    • 2011
  • For the purpose of enhancing usability of NWP (Numerical Weather Prediction), the quantitative precipitation prediction scheme was suggested. In this research, precipitation by leading time was predicted using 3-hour rainfall accumulation by meso-scale numerical weather model and AWS (Automatic Weather Station), precipitation water and relative humidity observed by atmospheric sounding station, probability of rainfall occurrence by leading time in June and July, 2001 and August, 2002. Considering the nonlinear process of ranfall producing mechanism, the ANN (Artificial Neural Network) that is useful in nonlinear fitting between rainfall and the other atmospheric variables. The feedforward multi-layer perceptron was used for neural network structure, and the nonlinear bipolaractivation function was used for neural network training for converting negative rainfall into no rain value. The ANN simulated rainfall was validated by leading time using Nash-Sutcliffe Coefficient of Efficiency (COE) and Coefficient of Correlation (CORR). As a result, the 3 hour rainfall accumulation basis shows that the COE of the areal mean of the Korean peninsula was improved from -0.04 to 0.31 for the 12 hr leading time, -0.04 to 0.38 for the 24 hr leading time, -0.03 to 0.33 for the 36 hr leading time, and -0.05 to 0.27 for the 48 hr leading time.

Observations on the Coastal Ocean Response to Typhoon Maemi at the East Sea Real-time Ocean Buoy (동해 실시간 해양관측 부이로부터 관측한 태풍 매미에 대한 연안해양의 반응 고찰)

  • Nam, Sung-Hyun;Yun, Jae-Yul;Kim, Kuh
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.9 no.3
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    • pp.111-118
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    • 2004
  • An ocean buoy was deployed 10 km off Donghae city, Korea at a depth of 130 m to measure meteorological (air pressure, air temperature, wind speed, wind gust, wind direction, relative humidity) and oceanographic data (water properties and currents in the whole column) in real-time. The buoy recorded a maximum wind gust of 25 m/s (10 minutes' average speed of 20 m/s) and a minimum air pressure of 980 hPa when the eye of typhoon Maemi passed by near the Uljin city, Korea at 03:00 on 13 September 2003. The wave height reached maximum of 9 m with the significant wave height of 4 m at 04:00 (1 hour after the passage of Maemi). The currents measured near the surface reached up to about 100 cm/s at 13:00 (10 hours after the passage of Maemi). The mixed layer (high temperature and low salinity) thickness, which was accompanied by strong southward current, gradually increased from 20 m to 40 m during the 10 hours. A simple two layer model for the response to an impulsive alongshore wind over an uniformly sloping bottom developed by Csanady (1984) showed reasonable estimates of alongshore and offshore currents and interface displacement for the condition of typhoon Maemi at the buoy position (x=8.15 km) during the 10 hours.

The Effects of Transformational, Transactional Leadership on the Creativity of Team Members in R&D Organization: Mediating Effect of Team Climate and Moderating Effect of Organizational Culture (변혁적, 거래적 리더십이 연구개발조직 구성원의 창의성에 미치는 영향: 팀 풍토의 조절효과 및 조직문화의 조절효과)

  • Seo, Jeong-Seok;Kim, Byung-Keun
    • Journal of Korea Technology Innovation Society
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    • v.20 no.3
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    • pp.684-708
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    • 2017
  • This paper investigates the effects of transformational leadership and transactional leadership on the creativity of members in R&D organizations. We also analyze the leadership mechanism and the influence of effective environment by using team climate as a mediator and using adhocracy and hierarchy organizational culture as moderator. Data were collected through surveys of Korean Public Research Institutes conducting mainly basic science and applied sciences. 327 valid samples were tested using a structural equation model (SEM). Empirical results confirm that transactional leadership exhibits stronger direct effect on the creativity than transformational leadership. However, in indirect effects mediated by creative team climate, transformational leadership is found to be stronger than transactional leadership. It may reflect the characteristics of R&D organization. Also, through the verification of the moderating effect of the organizational culture, the adhocracy organizational culture appears to improve the creativity and the hierarchical organizational culture appears to inhibit the creativity. It is confirmed that the influence of organizational culture is statistically significant in R&D organizations with strong autonomy and independence. It is suggested that the leadership on the creativity of the members in the R&D organization may be indirect in the context of the team and the organization as well as the direct effects according to the type.

Turnover intention and Its Influencing factors among care workers (요양보호사의 이직의도 및 영향요인)

  • Sung, kyoung-Ja
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.5
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    • pp.285-293
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    • 2017
  • This study examined the causal relationship among job stress, fatigue, and job satisfaction, which affect the turnover intention of elderly nursing home care workers. Data were collected from Sep.15 to Sep. 30, 2014. Structured self-administered questionnaires were delivered and collected without the respondents' personal information. The subjects were 232 female care workers working in nursing homes in D city. The data were analyzed using the SPSSWIN 21.0 and AMOS 21.0 programs. Covariance structure analysis was performed to estimate the causal relationship between the variables affecting the turnover intention of care workers. The results of the analysis were as follows. The variables included in this study were fatigue, which comprised 4.9% of job stress. Job satisfaction explained 54.6% of job stress and fatigue. The turnover intention was 46.2% due to job stress, fatigue, and job satisfaction. In other words, job stress, fatigue, and job satisfaction had a direct or indirect effect on the turnover intention of care workers. In conclusion, job stress, fatigue, and job satisfaction affect the turnover intention. Therefore, a policy to improve the work environment and working conditions is needed to reduce the turnover intention of care workers, and fulfill their duties in a stable life time workplace.

A Study on the Reasons for Participation in the Training of the Work-Learning Parallel Program (중소기업 일·학습병행제의 훈련 참여 이유에 관한 연구)

  • Park, Chan-Jun;Lim, Sang-Ho
    • Industry Promotion Research
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    • v.5 no.1
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    • pp.47-52
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    • 2020
  • In this study, parallel work-learning training, which was started in 2013 as a pre-employment promotion policy, is an important factor that determines the success or failure of training. As a time when various institutional supplementation is needed to encourage company participation, this study is to identify the factors of participation of companies participating in work-learning parallel. To this end, a questionnaire survey was conducted of companies participating in parallel work-learning in Chungnam, and the results were analyzed using the structural equation model. As a result of the study, the reason for the company's participation in parallel work-learning was firstly, 84% of government subsidy received education and training expenses. Second, 66% of workers were able to pay less than regular workers, and thirdly, it was easy to hire new employees in the field. 26%, 17% of them were invited by acquaintances for no particular reason. Therefore, the study suggests that participation in the work-learning parallel training contributes to the management costs, management of employee turnover, and human resource development. In future research, it is necessary to subdivide tests and estimates by conducting studies on regions, occupations, gender, wages, and years of service in Korea.

An Analysis for the Causality between Regional Knowledge Production Activity and Regional Economic Growth (지식창출활동과 지역경제성장 간의 인과관계 분석)

  • Lee, Hee-Yeon;Lee, Je-Yeon
    • Journal of the Economic Geographical Society of Korea
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    • v.13 no.3
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    • pp.297-311
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    • 2010
  • The purpose of this study is to analyze the causality among GRDP, patent, investment of R &D, and researcher among 16 Metropolitan cities and provinces in Korea. Using the annual data ranged from 1998 to 2008, the causality test for time-series data such as unit roots test and Granger causality test were performed. We estimate the Panel-Var of the four variables to find out the various Granger causal relations for two groups which are classified by the patent productivity. The panel data causality results reveal that there are bidirectional causality relations among four variables for the more patent-productivity group. The patent has bi-directional effects on GRDP and R&D. The patent cause GRDP and vice versa, patent cause R&D and vice versa. Patent not only has strong direct impact on GRDP and R&D but also has affected by the increase of GRDP and R&D through the interactive feedback mechanism. However, the causality patterns are somewhat different between the more patent-productive region and the less patent-productive region. There exists one directional causality between the R&D and GRDP for the less patent-productivity group. Such result may imply that the type of regional innovation policy should be differentiated between two groups. Regional economic policy efforts should be placed on increasing the knowledge productivity and on strengthening the regional competitiveness through the regional innovative infrastructure.

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An Analysis of the Effects of Political and Economic Forces on the Export of Renewable Energy Technologies (재생에너지 기술의 수출에 대한 정치·경제요인의 영향 분석)

  • Sung, Bong-Suk;Nian, Liu
    • Management & Information Systems Review
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    • v.37 no.2
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    • pp.209-233
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    • 2018
  • This study investigates the question of how political and economic factors may affect the export of renewable energy technologies. The relationships are tested using panel data for 19 OECD member countries over the period 1992-2012. Before establishing the empirical model, the current study checks the characteristics of the panel data, which includes various panel framework analyses, such as tests for the presence of normality, structural breaks, first-order autocorrelation, heteroscedasticity, cross-sectional dependence, panel unit-root. From the panel framework analyses, a dynamic panel model is established to test the relationship between the variables examined in this study. In order to reduce the bias of the estimation of the dynamic panel model and obtain efficient parameters, this study uses the bias-corrected least square dummy variable(LSDVC) estimator to estimate the empirical model. The results of this study show that governmental policies expressed as coercive pressure and market size positively affect the export growth of renewable energy technologies. However, public pressure and traditional energy industry have no significant effects on export performance. Policy implications are presented based on the results of this study.

The Effects of Mothers' Parenting Stress on Chilren's Learning Readiness Mediating Effects of Paren-Child Interactions and Parental Attitudes (어머니의 양육 스트레스가 아동의 학습준비도에 미치는 영향: 부모-자녀 상호작용과 온정적 양육태도의 매개효과)

  • Kim, Yeoung-Mi
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.12
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    • pp.563-573
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    • 2019
  • The purpose of this study is to confirm whether the parenting stress of mothers with preschool children mediated the parent-child interaction and parenting attitude on children's learning readiness. Data was used from the 5th (2012) to 7th (2014) Korean Children's Panel, and a total of 1,480 data sets were used for the analysis. The age of study participants was five years old. The Amos 23.0 program was used as an analytical tool, and the structural equation model analysis was applied to estimate the path coefficient corresponding to the research question. First, it was expected that mothers' parenting stress negatively affected the parent-child interaction, mother's parenting attitude, and children's readiness. Second, it was assumed that parent-child interaction and the mother's warm parenting attitude were positively significant to children's readiness. Third, the relationship between the parenting stress of mothers and children's learning readiness was partially mediated by a positive parenting attitude. The current study supplies valuable data to establish the educational support and efficiency strategy for domestic children. This study is meaningful in that it provides basic data in preparing a plan to more effectively provide educational support for domestic children.

An Analysis of the Productivity Changes of Korean Pharmaceutical Industry Using Bootstrapped Malmquist Index (Bootstrapped Malmquist 지수를 이용한 국내 의약품산업의 생산성 변화 요인 분석에 관한 연구)

  • So, Soon-Hu
    • Management & Information Systems Review
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    • v.35 no.4
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    • pp.141-153
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    • 2016
  • This study estimates the productivity change of pharmaceutical industry and decompose the change into technical efficiency change and technological change to explore ways to improve the productive efficiency. Unlike most previous studies, this study employs the non-radial and non-oriented slacks-based Malmquist productivity index which can deals directly with the input excesses and output shortfalls. In addition a smoothed bootstrap method is applied to estimate statistical confidence intervals for the Malmquist Index and its components. For the empirical analysis a balanced panel data set is constructed covering ten years over the period from 2005 to 2014. The input variables used in this study are number of workers, tangible assets and major production cost. The gross production is selected as a main output variable. The empirical results suggest that the productivity of pharmaceutical industry has decreased due mainly to decline in the technological progress rather than improvements in technical efficiency. An analysis result shows that the scale efficiency outweighs the pure efficiency in determining the technical efficiency of pharmaceutical industry. Therefore, in order to enhance the competitiveness of domestic pharmaceutical industry, it is important to continue supporting policies to promote the technology innovation capability through efficient R&D investment and industry reform strategy.

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Regionalization of Extreme Rainfall with Spatio-Temporal Pattern (극치강수량의 시공간적 특성을 이용한 지역빈도분석)

  • Lee, Jeong-Ju;Kwon, Hyun-Han;Kim, Byung-Sik;Yoon, Seok-Yeong
    • Proceedings of the Korea Water Resources Association Conference
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    • 2010.05a
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    • pp.1429-1433
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    • 2010
  • 수공구조물의 설계, 수자원 관리계획의 수립, 재해영향 검토 등을 수행할 때, 재현기간에 따른 확률개념의 강우량, 홍수량, 저수량 등을 산정하여 사용하게 되며, 보통 대상지역의 장기 수문관측 자료를 이용하여 수문사상의 확률분포를 산정한 후 재현기간을 연장하여 원하는 설계빈도에 해당하는 양을 추정하게 된다. 미계측지역 또는 관측자료의 보유기간이 짧은 지역의 경우는 지역빈도 분석 결과를 이용하게 된다. 지역빈도해석을 위해서는 강우자료들의 동질성을 파악하는 것이 가장 기본적인 과정이 되며 이를 위해 통계학적인 범주화분석이 선행되어야 한다. 지점 빈도분석의 수문학적 동질성 판별을 위해 L-moment 방법, K-means 방법에 의한 군집분석 등이 주로 사용되며 관측소 위치좌표를 이용한 공간보간법을 적용하여 시각화하고 있다. 강수량은 시공간적으로 변하는 수문변량으로서 강수량의 시간적인 특성 또한 강수량의 특성을 정의하는데 매우 중요한 요소이다. 이러한 점에서 본 연구를 통해 강수지점의 공간적인 좌표 및 강수량의 양적인 범주화에 초점을 맞춘 기존 지역빈도분석의 범주화 과정에 덧붙여 시간적인 영향을 고려할 수 있는 요소들을 결정하고 이를 활용할 수 있는 범주화 과정을 제시하고자 한다. 즉, 극치강수량의 발생 시기에 대한 정량적인 분석이 가능한 순환통계기법을 이용하여 관측 지점별 시간 통계량을 산정하고, 이를 극치강수량과 결합하여 시 공간적인 특성자료를 생성한 후 이를 이용한 군집화 해석 모형을 개발하는데 연구의 목적이 있다. 분석 과정에 있어서 시간속성의 정량화 및 일반화는 순환통계기법을 사용하였으며, 극치강수량과 발생시점의 속성자료는 각각의 평균과 표준편차를 이용하였다. K-means 알고리즘을 이용해 결합자료를 군집화 하고, L-moment 방법으로 지역화 결과에 대한 검증을 수행하였다. 속성 결합 자료의 군집화 효과는 모의데이터 실험을 통해 확인하였으며, 우리 나라의 58개 기상관측소 자료를 이용하여 분석을 수행하였다. 예비해석 단계에서 100회의 군집분석을 통해 평균적인 centroid를 산정하고, 해당 값을 본 해석의 초기 centroid로 지정하여, 변동적인 클러스터링 경향을 안정화시켜 해석이 반복됨에 따라 군집화 결과가 달라지는 오류를 방지하였다. 또한 K-means 방법으로 계산된 군집별 공간거리 합의 크기에 따라 군집번호를 부여함으로써 군집의 번호순서대로 물리적인 연관성이 인접하도록 설정하였으며, 군집간의 경계선을 추출할 때 발생할 수 있는 오류를 방지하였다. 지역빈도분석 결과는 3차원 Spline 기법으로 도시하였다.

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