• Journal of Korean Society on Water Environment
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• v.28 no.4
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• pp.582-594
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• 2012

A simple ecohydorlogic model that simulates hydrologic components and vegetation dynamics simultaneously based on equations of soil water dynamics and vegetation's growth and mortality is discussed. In order to simulate ungauged watersheds, the proposed model is calibrated with indirected estimated observation data set; 1) empirically estimated annual vaporization, 2) monthly surface runoff estimated by NRCS-CN method, and 3) vegetation fraction estimated by SPOT/VEGETATION NDVI. In order to check whether the model is performed well with indirectly estimated data or not, four upper dam watersheds (Andong, Habcheon, Namgang, Milyang) in Nakdong River watershed are selected, and the model is verified.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1870-1875
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• 2006

This study was carried out to investigate the applicability of SAC-SMA model with parameters which were derived from analytical relationships proposed by Koren etc. (2000), with various data of soil properties in a basin. The studied basin is Yongdam dam basin and the daily runoff with 2003-year hydrological data was simulated. Simulated runoff results were compared with those measured at three check points(Chuchun, Donhyang and Yongdam) and analyzed through the statistical techniques such as VE(Volume Error), RMSE(Root Mean Squared Error) and CORR(Correlation). As a result of analyses, the good agreement was obtained between simulated and measured results.

• Journal of The Korean Society of Agricultural Engineers
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• v.48 no.2
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• pp.37-43
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• 2006

A hydrological drought index, MSWSI (Modified Surface Water Supply Index) was suggested based on SWSI (Surface Water Supply Index). With the available data of spatially distributed observation station of precipitation, dam storage, stream water level and natural groundwater level, South Korea was divided into 32 regions. This was conducted to represent the calculated index as a spatially distributed information. Monthly MSWSI was evaluated for the period of 1974 and 2001. It is necessary to compare this result with PDSI (Palmer Drought Severity Index) and SPI (Standard Precipitation Index), and check the applicability of the suggested index in our hydrological drought situation.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.316-316
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• 2021

Erosion in a watershed is one of the main sources of sediment inflow in dams. While sediment management practices can be performed to reduce and manage sedimentation in reservoirs, managing the sediment inflow before it reaches the reservoir should also be consider. The accurate location of areas with high erosion and deposition rates should be determined in order to propose an appropriate sediment management procedure such as the construction of check dams. In this study, the projected rainfall from HadGEMRA-3 for RCP 8.5, was used in C-SEM, a distributed rainfall-erosion model, to determine the projected spatial erosion patterns in Cheoncheon catchment, which is located in the upstream part of Yongdam Dam.

• Journal of Korean society of Dental Hygiene
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• v.4 no.2
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• pp.277-291
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• 2004

The purpose of this study is to analyze the dental hygienists' overall performance in operative restoration and the clinical performance in operative restoration according to dental hygienists' career and to provide basic data for establishing the appropriate range of dental hygienists' work. Subjects of this study are 339 dental hygienists working at dental clinic and hospital nationwide, selected by their working place, career, type of clinic, and location of clinical institution. The distribution of people who responded to the survey shows that 81 belong to beginner level(less than 2 years since entering clinic), 115 intermediate level(2 to 3 years since entering clinic), 81 higher level(4 to 5 years since entering clinic) and 62 advanced level(more than 6 years since their entering clinic). In terms of the types of clinical institution, 178 belong to dental clinics and 161 belong to dental hospitals. The survey used in this study are focused on perception about clinical performance in operative dentistry and adequacy of the work. Operative dentistry consists of operative restoration and endodontic therapy. The operative restoration consists of 15 categories such as patient welcoming, examination and diagnosis, planning of treatment, anesthesia, control of moisture, cavity preparation, pulp protection, matrix band application, amalgam filling, resin filling, glass ionomer cement filling, abrasive strip removal, rubber dam removal, bite check and polishing, patient education, and arrangement. The reliability was Cronbach's Alpha .9453. SPSS 10.0 for Windows was used to analyze the responses. One way ANOVA was utilized to verify the differences in the dental hygienists' job performance in operative restoration and their job performance according to career. When significant difference was found. Duncan multi comparison post hoc was done. To sum up the results of this study, patient welcoming look the first place in the operative restoration. It was followed by patient education, examination and diagnosis, introducing treatment plan, resin filling, glass ionomer cement filling, amalgam filling, bite check and polishing, anesthesia, pulp protection, control of moisture, abrasive strip removal, cavity preparation, matrix band application, rubber dam removal, and anesthesia. In terms of the clinical performance by career, there were significant differences in 19 activities such as medical eraluation, oral examination, patient charting, intra oral readio graphs, firm developing fixing mounting, curing light gun, education of attention content after operation. Based on the results of this study, the specific range of operative restoration for dental hygienists should be focused on providing basic data for dentists' diagnosis, alleviation of fear and aching accompanied by injection and anesthesia, data providing for dentists' decision of anesthesia degree, and maximization of control of moisture.

• Journal of the Korean association of regional geographers
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• v.11 no.1
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• pp.29-39
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• 2005

Silk Road is the term involving all traffic roads connecting the East to the West, and ancient Korean culture has became globalized through Silk Road. In this paper, natural environment of Silk Road is considered as fundamental data in order to understand the Western culture introduced through Silk Road. Silk Road region is classified into Loess Plateau district; arid basin district; and high mountains district; Hesi Corridor(河西回廊) is the transition zone that the southeastern part of $W{\breve{u}}w{\bar{e}}i$(武威) is Loess Plateau district; other northwestern part is arid basin district Loess Plateau district, composed of homogeneous fines, has experienced dramatic soil loss by bringing under cultivation. At recent times, reforestation and construction of check-dam have been in operation to cope with this problems, Arid basin district; although at midlatitude, is desert climate because it is far from the ocean and is surrounded by high mountains. Oasis of Hesi Corridor is continuous linearly, but that of arid basin district is sporadic. In $H{\bar{a}}mi$ and $T{\breve{u}}l{\breve{u}}f{\bar{a}}n$(吐魯番) fruit-growing using karez flourishes, And glacier of $Ti{\bar{a}}nshian$(天山) Mts. and $Q{\bar{i}}lian$(祁連) Mts. is very important to arid basin district because of supplying water resource. In the tundra zone surrounding alpine glacier, are distributed widely solifluction lobes and earth hummocks.

• Journal of Korea Water Resources Association
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• v.33 no.4
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• pp.393-405
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• 2000

Monthly runoff was estimated using TOPMODEL which simulates ground water movement as well as surface runoff in the area of catchment. SAYUN dam which is being operated by Korea Water Resources Corporation was selected for the study, and the topographic factors of the watershed were analyzed using 1/5,000 digital map and GIS software(Arc/Info). The comparison shows good agreement between observed monthly runoff and the computation results simulated by using TOPMODEL. The catchment area of SAYUN dam was modeled by using various grid sizes in order to check the sensitivity of grid size, and the grid size of 180m was found most proper among 6 different sizes. TOPMODEL was also found superior to the existing monthly runoff models such as Kajiyama, KRIHS and Tank. Because the model requires limited number of parameters and considers topographic aspects, it is reckoned to be very useful for practical use.

• Journal of the Earthquake Engineering Society of Korea
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• v.18 no.4
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• pp.161-170
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• 2014

Newmark-type deformation analysis has rarely been done in Korea due to the popularity of simple pseudo-static limit equilibrium analysis and detailed time-history FE/FD dynamic analysis. However, the Korean seismic dam design code updated in 2011 prescribes Newmark-type deformation analysis as a major dynamic analysis method for the seismic evaluation of fill dams. In addition, a design PGA for dynamic analysis is significantly increased in the code. This paper aims to study the seismic evaluation of four existing large fill dams through advanced FEM/Newmark-type deformation analyses for the artificial earthquake time histories with the design PGA of 0.22g. Dynamic soil properties obtained from in-situ geo-physical surveys are applied as input parameters. For the FEM/Newmark analyses, sensitivity analyses are performed to study the effects of input PGA and $G_{max}$ of shell zone on the Newmark deformation. As a result, in terms of deformation, four fill dams are proved to be reasonably safe under the PGA of 0.22g with yield coefficients of 0.136 to 0.187, which are highly resistant for extreme events. Sensitivity analysis as a function of PGA shows that $PGA_{30cm}$ (a limiting PGA to cause the 30 cm of Newmark permanent displacement on the critical slip surface) is a good indicator for seismic safety check. CFRD shows a higher seismic resistance than ECRD. Another sensitivity analysis shows that $G_{max}$ per depth does not significantly affect the site response characteristics, however lower $G_{max}$ profile causes larger Newmark deformation. Through this study, it is proved that the amplification of ground motion within the sliding mass and the location of critical slip surface are the dominant factors governing permanent displacements.

• Journal of Korean Society of Disaster and Security
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• v.16 no.4
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• pp.33-43
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• 2023

The impact of prolonged rainfall, such as during the monsoon season or intense concentrated rainfall over a short period, can lead to mountainous disasters such as landslides and debris flows. These events, such as landslides and debris flows, cause both human and material damage, prompting the implementation of various measures and research to prevent them. In the context of researching debris flow disasters, numerical models for debris flows provide a relatively simple way to analyze the risk in a study area. However, since empirical equations are applied in these models, yielding different results and variations in input variables across models, the validation of numerical models becomes essential. In this study, a numerical model for debris flows was employed to compare and analyze the mitigation effects of facilities such as check dams and water channel work, aiming to reduce the damage caused by debris flows.

• Journal of the Korean GEO-environmental Society
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• v.19 no.4
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• pp.33-38
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• 2018

The internal erosion due to poor compaction of the material was the main cause of collapse of the embankment in Korea. The assessment of the compaction state of the dam body was a very important check in the safety diagnosis of the embankment. In this study, the correlation between dynamic cone penetration test and plate loading test which is the most typical compaction evaluation technique was analyzed to verify the applicability of the dynamic cone penetration test in evaluating the compaction state of the dam body. The standard penetration tests were carried out six times to define soil properties and depth of the test site. The spatial distributions were obtained by the Kriging method after 15 times of plate loading tests and 47 times of dynamic cone penetration tests. The Pearson correlation coefficient between the spatial distribution of the plate loading test and the dynamic cone penetration test spatial distribution at the constant penetration depth was calculated. The load distribution in the plate loading test and the blow counts at penetration depths of 5 cm, 10 cm and 15 cm in the dynamic cone penetration test showed a weak positive correlation.