• Journal of Environmental Impact Assessment
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• v.27 no.3
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• pp.291-306
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• 2018

This study was designed to predict potential habitat of Japanese evergreen oak (Quercus acuta Thunb.) in Korean Peninsula considering its dispersal ability under climate change. We used a species distribution model (SDM) based on the current species distribution and climatic variables. To reduce the uncertainty of the SDM, we applied nine single-model algorithms and the pre-evaluation weighted ensemble method. Two representative concentration pathways (RCP 4.5 and 8.5) were used to simulate the distribution of Japanese evergreen oak in 2050 and 2070. The final future potential habitat was determined by considering whether it will be dispersed from the current habitat. The dispersal ability was determined using the Migclim by applying three coefficient values (${\theta}=-0.005$, ${\theta}=-0.001$ and ${\theta}=-0.0005$) to the dispersal-limited function and unlimited case. All the projections revealed potential habitat of Japanese evergreen oak will be increased in Korean Peninsula except the RCP 4.5 in 2050. However, the future potential habitat of Japanese evergreen oak was found to be limited considering the dispersal ability of this species. Therefore, estimation of dispersal ability is required to understand the effect of climate change and habitat distribution of the species.

• The Korean Journal of Applied Statistics
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• v.28 no.1
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• pp.61-74
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• 2015

Structural equation modeling (SEM) is a widely used in social sciences such as education, business administration, and psychology. In SEM, the latent variable score is the estimate of the latent variable which cannot be observed directly. This study uses stagewise structural equation modeling(stagewise SEM; SSEM) by partitioning the whole model into several stages. The traditional estimation method minimizes the discrepancy function using the variance-covariance of all observed variables. This method can lead to inappropriate situations where exogenous latent variables may be affected by endogenous latent variables. The SSEM approach can avoid such situations and reduce the complexity of the whole SEM in estimating parameters.

• Journal of the Korean Geographical Society
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• v.51 no.2
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• pp.201-217
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• 2016

We accessed the climate change effects on the distributions of warm-evergreen broad-leaved trees (shorten to warm-evergreens below) in the Korean Peninsula (KP). For this, we first selected nine warm-evergreens with the northern distribution limits at mid-coastal areas of KP and climate variables, coldest month mean temperature and coldest quarter precipitation, known to be important for warm-evergreens growth and survival. Next, species distribution models (SDMs) were constructed with generalized additive model (GAM) algorithm for each warm-evergreen. SDMs projected the potential geographical distributions of warm evergreens under current and future climate conditions in associations with land uses. The nine species were categorized into three groups (mid-coastal, southwest-coastal, and southeast-inland) based on their current spatial patterns. The effects of climate change and land uses on the distributions depend on the current spatial patterns. As considering land uses, the potential current habitats of all warm-evergreens decrease over 60%, showing the highest reduction rate for the Kyungsang-inland group. SDMs forecasted the expansion of potential habitats for all warm-evergreens under climate changes projected for 2050 and 2070. However, the expansion patterns were different among three groups. The spatial patterns of projected coldest quarter precipitation in 2050 and 2070 could account for such differences.

• Journal of the Korean Society for Library and Information Science
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• v.56 no.4
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• pp.455-472
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• 2022

The purpose of this study is to analyze variables affecting the number of circulated books which is one of the indicators representing the library use behavior. For the analysis, 2015-2019 data for public libraries was acquired from the National Library Statistics System. The Latent Growth Model estimating a latent intercept and a latent slop based on the individual library trajectories was applied. The results are as followed; first, the circulation rate tends to be decreased. Second, the most affecting factor on the library circulation decrease was the collection budget. This study suggests increasing a collection budget in order to prevent the library circulation decrease while the library is operating in a daily routine.

• Journal of the Korean earth science society
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• v.33 no.7
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• pp.583-595
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• 2012

The potential for tropical cyclogenesis in a given oceanic and atmospheric environments can be represented by genesis potential index (GPI). Using the 18 Coupled Model Inter Comparison Project phase 5 (CMIP5) models, the annual cycle of GPI and interannual variability of GPI are analyzed in this study. In comparison, the annual cycle of GPI calculated from reanalysis data is revisited. In particular, GPI differences between CMIP5 models and reanalysis data are compared, and the possible reasons for the GPI differences are discussed. ENSO (El Nino and Southern Oscillation) has a tropical phenomenon, which affects tropical cyclone genesis and its passages. Some dynamical interpretations of tropical cyclogenesis are suggested by using the fact that GPI is a function of four large-scale parameters. The GPI anomalies in El Nino or La Nina years are discussed and the most contributable factors are identified in this study. In addition, possible dynamics of tropical cyclogenesis in the Northern Hemisphere Pacific region are discussed using the large-scale factors.

• Journal of Digital Convergence
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• v.16 no.6
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• pp.385-397
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• 2018

This study used latent class analysis to identify heterogeneous subgroups with respect to health condition among adolescents. We also examined associations between latent classes and verified to determine how the patterns of health condition relate to social capital. This study used data from Korean Survey on the Rights of Children and Youth in 2015, which consists of 6,912 from middle and high school students. The findings are as follows. Latent class analysis revealed a three-class solution. Results indicated that family social capital and school capital significantly verified to the above latent classes all family type. But, community social capital not significantly predicted to the above latent classes only single parent families. Policy implications for improving the health condition of adolescents are discussed.

• Journal of Gifted/Talented Education
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• v.18 no.3
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• pp.519-542
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• 2008

The purpose of the present study was to examine the emotional characteristics related to gifted children's happiness, such as happiness index, optimism, psychological wellbeing, and school education happiness. For the study, 201 gifted students who were currently enrolled in gifted education centers, 124 potentially gifted students who were nominated by teachers for their scientific interests and high performances, and 141 general middle school students participated in the study. The results indicated that both the gifted and the potentially gifted students showed significantly higher emotional characteristics related to happiness compared to the general students. There was no significant difference between the gifted and the potentially gifted in the diverse aspects of happiness. Interestingly, significant interaction between gender and giftedness was found. Girls were happier when they were identified as the gifted, compared to the boys. Variables related to the happiness were also investigated, and the results indicated that the peer relationship and the family happiness were the most important variables that explained gifted children's happiness in general.

• Journal of The Korean Association For Science Education
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• v.31 no.6
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• pp.876-886
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• 2011

This study was carried out to investigate the difference of gender of academic self-efficacy, external motivation, interest and science achievement for high school students of Korea and to verify the structural relationship among these variables using PISA 2006 data. The major findings of this study are as follows. According to Multi-group analysis, Latent means analysis (LMA), where boys were used as the reference group, girls showed lower latent mean values on the academic self-efficacy, extrinsic motivation and interest. Academic self-efficacy was found to have a greater effect on achievement compared to external motivation and interest. According to structural equation modeling (SEM) analysis, academic self-efficacy and extrinsic motivation affected interest. Academic selfefficacy, external motivation, and interest affected science achievement. Lastly, interest mediated academic selfefficacy and external motivation on science achievement.

• Journal of the Korean Geographical Society
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• v.35 no.5
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• pp.665-680
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• 2000

본 연구의 목적은 미국의 산타아나 강 상류 유역분지 내 잠재적 퇴적물 생산량의 공간적 분포 패턴을 고찰하는데 있다. 이를 위해 산타아나 강 상류지역을 42개의 하부 유역분지로 나눈 후에 각 유역분지에 퇴적물 생산량에 영향을 주는 지형 기복 요소, 면적-형태 요소, 지질 요소, 기후 요소와 관련하여 20개의 변수를 GIS를 이용하여 추출하였다. 이러한 20개의 변수들을 기초로 군집분석하여 42개 하부 유역분지들의 잠재적 퇴적물 생산량을 평가한 결과 4개 지역으로 구분되었다. 평가 결과 <발톤> 평기자 포함된 제2지역이 산타아나 강 상류 유역분지에서 가장 퇴적작용이 왕성한 지역으로 나타났다. 이 지역은 낮은 기복 및 고도와 미고화된 물질로 피복된 지역이 97%를 차지하고 있다. 잠재적 퇴적물 생산량이 가장 높은 지역은 제 2지역의 상류부에 분포하는 유역분지들(제 4지역)로서 높은 기복과 고도뿐만 아니라 침식 면적이 넒으며, 과거의 빙하작용이 있었던 지역이다. 특히 단층선이 퇴적작용이 크게 이루어지고 있는 지역(제2지역)과 잠재적 퇴적물 생산량이 가장 높은 지역(제4지역) 사이에 분포하고 있어, 사면경사의 급변으로 제 2 지역의 퇴적작용은 더욱 가속화 될 것이다.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.67-70
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• 2012

현재 국내외에서는 양질의 증발산을 관측하여 활용하기 위해 증발접시 (evaporation pan), 침루계 (lysimeter) 등을 이용하여 실측하거나 Flux Tower에서 Eddy covariance technique, Bowen ratio method 등을 이용하여 경험적으로 산정하고 있다. 이러한 방법으로 산정되는 증발산은 크게 두 분류로 나눌 수 있다. 일반적인 기후 상태에서 유역의 토양이 증발산에 방해를 받지 않을 정도로 충분히 물을 포함하고 있고, 식생이 조밀한 상태에서의 증발산량을 의미하는 잠재 증발산과 실제 산정치인 실제 증발산으로 나눌 수 있다 (Thornthwait, 1939). 본 연구에서는 유역의 잠재 증발산을 산정하여 실제 증발산과 비교를 통해 적용성을 확인하고자 한다. 잠재 증발산을 산정하는 방법은 Moderate Resolution Imaging Spectroradiometer (MODIS) 인공위성 데이터를 이용한 원격탐사 기술을 적용하여 산정한다. 원격탐사 기술은 지상 관측의 단점을 보완한 것으로써, 날씨, 인간 활동 등 주변 외부 환경의 영향에 민감하게 반응하여 공간적인 분포 현황을 파악하는 것이 어려운 지상 관측의 한계점을 대체하기 위한 방법이다. 이들 방법으로는 가장 널리 쓰이는 Penman-Monteith (Penman, 1948; Monteith, 1965), 일별 최대, 최저, 평균 기온을 이용한 Hargreaves 방법 (Hargreaves, 1985)과 Priestley-Taylor 방법 (Priestley and Taylor, 1972) 등의 세 가지 방법을 소개하였다. 세 가지 방법으로 산정된 잠재 증발산을 통해 해당 유역의 잠재 증발산의 공간적인 거동을 파악해 볼 수 있다.