• Journal of Wetlands Research
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• v.14 no.4
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• pp.519-535
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• 2012

In order to establish a rainfall-runoff model, calibration of hydrological parameters for the model is very important. Especially, Curve Number(CN), estimated by NRCS method, is a main factor to apply unit hydrograph theory to calculation of peak discharge. For using NRCS method, it is needed selecting AMC because CN is strongly connected with that. In this study, we focus our concern on finding a applicable standard for selecting AMC for CN. For this, three dams which are Boryeong, Habchon, Namgang are selected as target basins to use observed data including rainfall and dam inflow. As a result of this research, it is found that CN must be included as a calibrated parameter to calculate effective rainfall for the rainfall-runoff model. Also, it is preferred to use PWRMSE of HEC-HMS program as a objective function for optimizing hydrological parameters. From the analyzing result of variation of AMC for peak discharge, it is recommended to apply AMC-III to estimation of CN for calculating effective rainfall of design hydrograph.

• Korean Journal of Remote Sensing
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• v.30 no.5
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• pp.587-596
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• 2014

Soil moisture is one of the most important interests in hydrological response and the interaction between the land surface and atmosphere. Estimation of Antecedent Wetness Conditions (AWC) which is soil moisture condition prior to a rainfall in the basin should be considered for rainfall-runoff prediction. In this study, Soil Wetness Index (SWI), Antecedent Precipitation Index ($API_5$), remotely sensed Soil Moisture ($SM_{rs}$), and 5 days ground Soil Moisture ($SM_{g5}$) were selected to estimate the AWC at four study area in the Korean Peninsula. The remotely sensed soil moisture data were taken from the AMSR-E soil moisture archive. The maximum potential retention ($S_{obs}$) was obtained from direct runoff and rainfall using Soil Conservation Service-Curve Number (SCS-CN) method by rainfall data of 2011 for each study area. Results showed the great correlations between the maximum potential retention and SWI with a mean correlation coefficient which is equal to -0.73. The results of time length representing the time scale of soil moisture showed a gap from region to region. It was due to the differences of soil types and the characteristics of study area. Since the remotely sensed soil moisture has been proved as reasonable hydrological variables to predict a wetness in the basin, it should be continuously monitored.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.3
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• pp.603-612
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• 2010

Recently, with the advance of computing and networking technique, the high speed internet becomes widespread, however, it is still hard job to do streaming the media which requires high network bandwidth over the internet. Previous VoD system researches for streaming over the internet mainly proposed techniques that controls the QoS(Quality of Service) of the media in proportion to the network status. Though, this could be the solution for the service provider while the service user who wants constant QoS may not satisfy with variable QoS. In the paper, we propose greedy precedent frame transmission technique, GPFT, for guarantee of constant QoS. In GPFT, Streaming VoD server prefetches precedent frames and transmits the frame greedily by increasing the frame transmission rate while the available network bandwidth is high. The GPFT uses the prefetched precedent frames to guarantee the QoS while the available network bandwidth is low. The experiment result shows that the proposed GPFT could guarantee the constant QoS by prefetching the frames adaptively to the network bandwidth with the characteristic of video stream.

• Journal of Korea Water Resources Association
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• v.50 no.10
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• pp.691-701
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• 2017

The objective of this study is to evaluate the long-term drought outlook information based on long-term forecast data for the 2015 drought event. In order to estimate the Standardized Precipitation Index (SPI) for different durations (3-, 6-, 9-, 12-months), we used the observation precipitation of 59 Automated Synoptic Observing System (ASOS) sites, forecast and hindcast data of GloSea5. The Receiver Operating Characteristic (ROC) analysis and statistical analysis (Correlation Coefficient, CC; Root Mean Square Error, RMSE) were used to evaluate the utilization of drought outlook information for the forecast lead-times (1~6months). As a result of ROC analysis, ROC scores of SPI(3), SPI(6), SPI(9) and SPI(12) were estimated to be over 0.70 until the 2-, 3-, 4- and 5-months. The CC and RMSE values of SPI(3), SPI(6), SPI(9) and SPI(12) for forecast lead-time were estimated as (0.60, 0.87), (0.72, 0.95), (0.75, 0.95) and (0.77, 0.89) until the 2-, 4-, 5- and 6-months respectively.

• Journal of the Korea Institute of Building Construction
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• v.17 no.2
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• pp.199-209
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• 2017

The measurement of business performance is important to secure the competitiveness of construction companies. Therefore, the purpose of this study is to analyze what is needed to increase the competitiveness of small & medium construction companies. In order to analyze efficiently, this study reconfirms the effectiveness of Key Performance Indicators(KPI) of construction companies selected from previous studies. The empirical analysis to find differences of KPI between small & medium construction companies and big construction companies is performed using the 4,286 construction company samples extracted by 'KIS-Value Data Base'. The results of the empirical analysis show that there are significant differences in characteristics of KPI between small & medium construction companies and big construction companies. Particularly, small & medium construction companies are relatively insufficient to invest for the purpose of preparation for future and long-term growth. Additionally, empirical tests reconfirm that most of the KPIs from previous survey studies are suitable as a performance indicators. The contribution of this study is to analyze empirically small & medium construction company's strong & weak points and the effectiveness of KPIs derived from previous studies.

• Journal of Korea Water Resources Association
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• v.44 no.7
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• pp.537-551
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• 2011

Based on optimal input data combination selected in the earlier study, Neuro-Fuzzy flood forecasting model linked Takagi-Sugeno fuzzy inference theory with neural network in Wangsukcheon and Gabcheon is established. The established model was applied to Wangsukcheon and Gabcheon and water levels for lead time of 0.5 hr, 1 hr, 1.5 hr, 2.0 hr, 2.5 hr, 3.0 hr are forecasted. For the verification of the model, the comparisons between forecasting floods and observation data are presented. The forecasted results have shown good agreements with observed data. Additionally to evaluate quantitatively for applicability of the model, various statistical errors such as Root Mean Square Error are calculated. As a result of the flood forecasting can be simulated successfully without large errors in all statistical error. This study can greatly contribute to the construction of a high accuracy flood information system that secure lead time in medium and small streams.

• Korean Journal of Health Education and Promotion
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• v.27 no.5
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• pp.73-78
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• 2010

Background: Although collaboration for community health is emphasized, the concept and process of collaboration are rather unclear. International research has classified the types of collaboration and focused on the factors influencing successful collaboration. Greater attention is needed for collaboration practice and research domestically. Findings: By the level of intensity, the types of collaboration range from simpler networking to more formal and sophisticated collaboration. A 4-stage collaboration development consists of formation, implementation, maintenance, and institutionalization stages. Influential factors for collaboration development include: shared goals; operational structure and process; sufficient resources; member and leadership characteristics; environment and climate for collaboration; and information exchange and communication. Discussion: Most of collaboration research so far has dealt with partnerships and coalition building with community-based organizations, and much attention is given to private-public partnership for health. Contextual understanding and collaborative environment are the foremost tasks for us to enhance collaboration for community health in our centralized public health system.

• Journal of Korean Library and Information Science Society
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• v.36 no.2
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• pp.49-68
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• 2005

The purpose of this study is to examine the research trends and their experiment results on the applications of the language models for information retrieval. We reviewed the previous studies with the following categories: (1) the first generation of language modeling information retrieval (LMIR) experiments which are mainly focused on comparing the language modeling information retrieval with the traditional retrieval models in their retrieval performance, and (2) the second generation of LMIR experiments which are focused on comparing the expanded language modeling information retrieval with the basic language models in their retrieval performance. Through the analysis of the previous experiments results, we found that (1) language models are outperformed the probabilistic model or vector space model approaches, and (2) the expended language models demonstrated better results than the basic language models in their retrieval performance.

• The Journal of Korean Association of Computer Education
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• v.16 no.1
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• pp.81-95
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• 2013

Academic procrastination has been a concern for educators. The purpose of this study is to investigate the relationship among task value, academic self-efficacy, autonomous motivation, self-regulated learning, and academic procrastination in e-learning courses. Based on the literature review, the path model was proposed and tested with 212 university students who registered in e-learning courses. The results showed that task value and academic self-efficacy positively influenced autonomous motivation and self-regulated learning, and autonomous motivation and self-regulated learning reduced the level of academic procrastination directly or indirectly. Implications and strategies to reduce procrastination were discussed based on the findings.

• The Journal of Korean Association of Computer Education
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• v.14 no.4
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• pp.21-31
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• 2011

User-created content(UCC) is on the rapid increase both in terms of quantity and the quality of sharing and enjoying each others. However, not much research has been done on school's adoption of this innovative contents for educational purposes. The aim of this case study is to identify the determinants of students' attitude toward using UCC in elementary school classes. This study employs the perceived educational value, ease of use, social influence, fun, computer self-efficacy, cooperativity and concentration as the antecedents of attitude, and collected 246 survey responses from 5th and 6th grade students. The results indicate that the perceived educational value, ease of use and socal influence have significant impact on the attitude toward using UCC. It was also found that the cooperativity, fun and ease of use determine the level of perceived educational value, and that the computer self-efficacy, fun and concentration influence the perceived ease of use. Some useful suggestions, concerning the utilizing UCC for educational purpose in elementary school classes, are also presented.