• Korean Journal of Remote Sensing
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• v.34 no.5
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• pp.721-738
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• 2018

The purpose of this study is to create landslide vulnerability using frequency ratio (FR) and evidential belief functions (EBF) model which are two methods of probability model and to select appropriate model for each region through comparison of results in Sacheon-myeon and Jumunjin-eup of Gangneung. 762 locations in Sacheon-myeon and 548 landscapes in Jeonju-eup were constructed based on the interpretation of aerial photographs. Half of each landslide point was randomly selected for modeling and remaining landslides were used for verification purposes. Twenty landslide-inducing factors classified into five categories such as topographic elements, hydrological elements, soil maps (1:5,000), forest maps (1:5,000), and geological maps (1:25,000) were considered for the preparation of landslide vulnerability in the study. The relationship between landslide occurrence and landslide inducing factors was analyzed using FR and EBF models. The two models were then verified using the AUC (curve under area) method. According to the results of verification, the FR model (AUC = 81.2%) was more accurate than the EBF model (AUC = 78.9%) at Jeonjun-eup. In the Sacheon-myeon, the EBF model (AUC = 83.6%) was more accurate than the FR model (AUC = 81.6%). Verification results show that FR model and EBF model have high accuracy with accuracy of around 80%.

• Journal of Korean Society for Geospatial Information Science
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• v.24 no.1
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• pp.17-24
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• 2016

At present, summer cloudburst and local torrential rainfalls have increased in this country, because of climatic change. Therefore, studies on prevention of soil loss have been actively proceeded, and Korea Forest Service has offered landslide hazard map. Landslide hazard map divides risks into 5 classes, by giving weight with 9 kinds of elements. In August 25 2014, soil loss occurred in the whole Oryun Tunnel, Geumjeong-gu, Busan, because of local torrential heavy rain. As a result of comparing with landslide hazard map, the area where soil loss occurred in reality is a safety zone on hazard map. Rainfall, soil map, geological map, forest type map, gradient, drainage network, watershed, basin shape, and efflux of the whole Oryun Tunnel where soil loss occurred were analyzed. As a result of an analysis, it is judged that soil, forest type, much efflux and peak discharge, degree of water network and basin shape of a place where landslide occurred are causes of soil loss. It is judged that efflux, peak discharge, and basin shape by the localized rainfall that is not considered in landslide hazard map of them are the biggest causes of soil loss. It is judged that efflux, peak discharge, degree of water network and basin shape by the rainfall are important through a study on a causual analysis on soil loss in the whole Oryun Tunnel where is one of occurrence area where a lot of propertywere lost by the record local torrential rainfalls. A localized torrential downpour should be prepared by considering these elements on judgement of a landslide hazard area.

• Journal of Science Education
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• v.38 no.2
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• pp.415-429
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• 2014

The purpose of this study was to develop the 'airplane' science program based on Renzulli's Enrichment Triad Model for the gifted elementary students and investigate the effects of the program on attitude toward self-directed learning attitude, attitude toward laboratory work, and creative personality. Participants were 37 gifted students of local elementary school gifted classrooms. The results of this study were as follows: First, self-directed learning attitude was improved significantly including all sub-areas. Second, the attitude toward laboratory work was improved significantly including all sub-areas. Third, creative personality was improved significantly including all sub-areas. Finally, students' satisfaction about program had an average of 4.52 out of 5 points. Boys showed higher satisfaction on 'program management' and 'teacher's activities' than girls.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.6
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• pp.384-392
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• 2000

To establish N fertilizer recommended scheme for the Chinese cabbage cultivation in green house based on the soil test of nitrate nitrogen, relationship among the content of soil nitrate and fertilizer effects and fertilizer N use efficiency were investigated from nine soils which differed amount of nitrate nitrogen from $14mg\;kg^{-1}$ to$226mg\;kg^{-1}$. The amount of nitrate nitrogen in soil showed a positive correlation with the dry weight of chinese cabbage in the plot of no fertilization. When the fertilizer effects were calculated by difference between the plots of fertilization and no fertilization in the dry weight and the amount of N uptake, a negative correlation was obtained between the amount of nitrate nitrogen in soils and the fertilizer effects. There was also a negative correlation between the amount of nitrate nitrogen in soils and fertilizer use efficiency. Recommendation of application rate of nitrogen fertilizer based on content of $NO_3-N$ in soils was evaluated by the regression equation among the content of soil nitrate, fertilizer effects and fertilizer N use efficiency. Incase the content of $NO_3-N$ nitrogen in soil is more than $200mg\;kg^{-1}$, No N fertilization is recommended; However, The standard N fertilization($320kg\;ha^{-1}$) is recommended for the soils with less than $50mg\;kg^{-1}$. For the soils ranged from $50mg\;kg^{-1}$ to $200mg\;kg^{-1}$ in the amount of nitrate nitrogen, an equation has been developed in order to calculate the recommended amount of fertilizer N.

• Economic and Environmental Geology
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• v.47 no.1
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• pp.49-59
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• 2014

Rainfall-induced landslides are caused by reduction of effective stress and shear strength due to rainfall infiltration. In order to analyze the susceptibility of landslides, the statistical analysis approach has been used widely but this approach has the limitation which cannot take into account of landslide triggering mechanism. Therefore, the physically based model which can consider the process of landslide occurrence was proposed and commonly used. However, the most previous physically based model analyses evaluate and consider the strength characteristics for saturated soil only in the susceptibility analysis. But the strength parameters for unsaturated soil such as matric suction should be considered with the strength parameters for saturated soil since the shear strength in unsaturated soil also plays important role in the stability of slope. Consequently this study suggested the modified physically based slope model which can evaluate strength characteristics for both of saturated and unsaturated soils. In addition, this study evaluated the thickness of saturated part in slope with rainfall intensity and hydraulic characteristics of slope on the basis of physically based model. In order to evaluate the feasibility, the proposed model was applied to practical example in Jinbu area, Gangwon-do, which was experienced large amount of landslides in July 2006. The ROC graph analysis was used to evaluate the validation of the model, and the analysis results were compared with the results of the previous analysis approach.

• Korean Journal of Environmental Agriculture
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• v.26 no.3
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• pp.223-227
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• 2007

This study was carried out to establish the reasonable level of nitrogen (N) fertilization based on soil nitrate nitrogen $(NO_3-N)$ content for cucumber (Cucumis sativus L.) under plastic film house. Cucumber plants were cultivated with standard and free N fertilization in eight soils which had various amount of $NO_3-N$ ranging from 67 to 343 mg/kg. The yield of cucumber was in the range of 1006 to 2369 g/plant depending on the nitrogen supplying capability of soils. The amount of $NO_3-N$ in the soil was negatively correlated with agronomic efficiency (AE) and N use efficiency (NUE). The critical level of soil $NO_3-N$ content for cucumber in N free fertilization was found to be about 260 mg/kg in Cate-Nelson analysis of variance between soil $NO_3-N$ and AE or NUE. Also the same critical soil $NO_3-N$ content was found in the yield and amount of N uptake of cucumber under N free fertilization. A standard N fertilization was required when soil $NO_3-N$ content was below 70 mg/kg. The optimal application rate of N fertilizer for cucumber in the soils containing $NO_3-N$ between 260-70 mg/kg could be recommended by the equation Y=-1.032X+269.2 (Y: N fertilization rate, kg/ha; X : soil $NO_3-N$ content mg/kg).

• Journal of the Korean Association of Geographic Information Studies
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• v.15 no.1
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• pp.119-132
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• 2012

Recently, forest soil sediment disasters resulting from locally concentrated heavy rainfall have been occurring frequently in steep slope areas. The importance of landslide hazard map is emerging to analyze landslide vulnerable areas. This study was carried out to develop HyGIS-Landslide based on Hydro Geographic Information System in order to analyze forest soil sediment disaster in the mountainous river basin. HyGIS-Landslide is one of HyGIS components designed by considering the landslide hazard criteria of Korea Forest Service. It could show the distribution of landslide hazard areas after calculating the spatial data. In this system, the user could reset the weight of hazard criteria to reflect the regional characteristics of the landslide area. This component provided user interface that could make the latest spatial data available in the area of interest. HyGIS-Landslide could be applied to the surveyor's compensation score and it was possible to reflect the landslide risk exactly through it. Also, it could be used in topographic analysis techniques providing spatial analysis and making topographical parameters in HyGIS. Finally the accuracy could be acquired by calculating the landslide hazard grade map and landslide mapping data. This study applied HyGIS-Landslide at the Gangwon-do province sample site. As a result, HyGIS-Landslide could be applied to a decision support system searching for mountainous disaster risk region; it could be classified more effectively by re-weighting the landslide hazard criteria.

• Geotechnical Engineering
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• v.9 no.4
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• pp.103-118
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• 1993

This paper presents the results of investigation of the rainstorm induced landslides occurred in the districts of Yongin, Ansung and Osan on July 21st 1991. More than two thousand and sirs hundred landsilides took place during or after a 3-t hours heavy rainfall and about 466 ha mountain slopes were affected by slope failures. The result of study on the effect of-iainfall on landslides shows that landslides began to occur where daily and maximum hourly rainfall exceeded 114mm and 40mm respectively, and all districts (myun) where maximum hourly rainfall exceeded 62mm were affected by landslides. The morphological study on landslides on Talbongsan area reveals that, by Walker's classi fication using D IL(failure depth ratio), 50% of the landslides were classified as flows, 20% of them as translational slides, and 30% were between flow and slide and there were few rotational slides. Over 90% of landslides tookplace at slopes of 20$^{\circ}$-40$^{\circ}$ in slope and 50m or shorter in length And more than 50% of the crown of slides locates at higher than 0.7 times of slope hight. Any differences between the kinds of tree in landslide resisting effects are shown in this case.

• Communications of Mathematical Education
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• v.31 no.1
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• pp.49-70
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• 2017

The purpose of this study was to investigate the relative influence of multiple error sources and to find optimal measurement conditions that obtain a desired level of reliability of a creative attitude test in mathematical creativity. This study analyzed the scores of the Creative Attitude Scale-Korea allowed to access publicly of 125 general students and 109 mathematically gifted students by performing a multivariate generalizability analysis. The main results were as follows. First, based on reliability, the Creative Attitude Scale-Korea was measured less precisely for mathematically gifted students. On the contrary, based on the conditional standard error of measurement, it was measured less precisely for general students. However, the Creative Attitude Scale-Korea showed strong reliability in both groups. Second, the optimal weights should adjust to .3, .3, .4 in mathematically gifted students and .4, .4, .2 in general students with three scoring components of divergent attitude, problem solving attitude, and convergent attitude based on the maximum reliability. Third, to approach desirable reliability, it is possible to use one component of divergent attitude in general students but three components of divergent attitude, problem solving attitude, and convergent attitude in mathematically gifted students. Finally this study proposed application plans for the Creative Attitude Scale-Korea and future directions of research.

• 한국노년학
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• v.38 no.3
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• pp.409-433
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• 2018

The purpose of this study is to examine the effect of contact with the elderly in a daily life on children's ageist attitude. Acknowledging the people's tendency to report in socially appropriate ways to the explicit attitude measurement, implicit measurement is introduced, and relation with the daily contact with elderly(DCE) is analyzed. The research question are as follows: 1) Are these two attitudes explained by different factors? 2) Can DCE alleviate both children's implicit and explicit ageist attitude? 3) How do the contact with grandparent and neighboring elderly affect the children's explicit and implicit ageist attitude? Data was collected from 503 fourth to sixth grade elementary school children. Child-Age Implict Association Test is used to measure implicit ageist attitude. Multinominal logistic analysis and ordered logistic analysis was applied. Followings are the main results: First, explicit and implicit ageist attitudes are found to be related with different predictors. Second, Elderly contact seems to lighten children's ageist attitude overall. Third, the effects of grandparental contact and the neighboring elderly contact on two different ageism were different. While the effect of elderly neighbor contact is limited to the expression of ageism, grandparental contact has a influence not only on the explicit but also on the implicit ageism, even though the effect on implicit attitude is limited in extent. Forth, not the quality of contact but the quantity of it was related to implicit ageist attitude. This result contradicts conventional idea of Intergroup Contact Theory. In the further research, the predictor of implicit ageist attitude need to be throughly examined.