• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.4
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• pp.385-410
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• 2016

The disposal facility in Gyeongju is planning to dispose of 800,000 packages of low- and intermediate- level radioactive waste. This facility will be developed as a complex disposal facility that has various types of disposal facilities and accompanying management. In this study, based on the comprehensive development plan of the disposal facility, a preliminary post-closure safety assessment is performed to predict the phase development of the total capacity for the 800,000 packages to be disposed of at the site. The results for each scenario meet the performance target of the disposal facility. The assessment revealed that there is a significant impact of the inventory of intermediate-level radionuclide waste on the safety evaluation. Due to this finding, we introduce a disposal limit value for intermediate-level radioactive waste. With stepwise development of safety case, this development plan will increase the safety of disposal facilities by reducing uncertainties within the future development of the underground silo disposal facilities.

• Journal of Korean Society of Transportation
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• v.35 no.6
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• pp.545-556
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• 2017

Various assessment indexes have been developed and utilized to evaluate the driver workload. However, existing workload assessment indexes do not fully reflect driving habits and driving patterns of individual drivers. In addition, there exists significant differences in the amount of workload experienced by a driver and the ability to overcome the driver's workload. To overcome these limitations associated with existing indexes, this study has developed a novel workload assessment index to reflect an individual driver's driving pattern. An average of the absolute values of the steering velocity for each driver are set as a threshold value in order to reflect the driving patterns of individual drivers. Further, the sum of the areas of the steering velocities exceeding the threshold value, which is defined as erratic steering area (ESA) in this study, was quantified. The developed ESA index is applied in evaluating the driver workload of manually driven vehicles in automated vehicle platooning environments. Driving simulation experiments are conducted to collect drivers' responsive behavior data which are used for exploring the relationship between the NASA-TLX score and the ESA by the correlation analysis. As a result, ESA is found to have the greatest correlation with the NASA-TLX score among the various driver workload evaluation indexes in the lane change scenario, confirming the usefulness of ESA.

• Journal of the Korea Concrete Institute
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• v.28 no.6
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• pp.685-693
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• 2016

The outer tank of a liquefied natural gas (LNG) storage tank is a longitudinally and meridionally pre-stressed concrete (PSC) wall structure. Because of the current trend of constructing larger LNG storage tanks, the pre-stressing forces required to increase wall strength must be significantly increased. Because of the increase in tank sizes and pre-stressing forces, an extreme loading scenario such as a bomb blast or an airplane crash needs to be investigated. Therefore, in this study, the blast resistance performance of LNG storage tanks was analyzed by conducting a blast simulation to investigate the safety of larger LNG storage tanks. Test data validation for a blast simulation of reinforced concrete panels was performed using a specific FEM code, LS-DYNA, prior to a full-scale blast simulation of the outer tank of a 270,000-kL LNG storage tank. Another objective of this study was to evaluate the safety and serviceability of an LNG storage tank with respect to varying amounts of explosive charge. The results of this study can be used as basic data for the design and safety evaluation of PSC LNG storage tanks.

• Journal of the Korea Concrete Institute
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• v.28 no.6
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• pp.673-683
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• 2016

In recent years, frequent terror or military attack by explosion, impact, fire accidents have occurred. Particularly, World Trade Center collapse and US Department of Defense Pentagon attack on Sept. 11 of 2001. Also, nuclear power plant incident on Mar. 11 of 2011. These attacks and incidents were raised public concerns and anxiety of potential terrorist attacks on major infrastructures and structures. Therefore, the extreme loading researches were performed of prestressed concrete (PSC) member, which widely used for nuclear containment vessel and gas tank. In this paper, to evaluate the blast resistance capacity and its protective performance of bi-directional unbonded prestressed concrete member, blast tests were carried out on $1,400{\times}1,000{\times}300mm$ for reinforced concrete (RC), prestressed concrete without rebar (PSC), prestressed concrete with rebar (PSRC) specimens. The applied blast load was generated by the detonation of 55 lbs ANFO explosive charge at 1.0 m standoff distance. The data acquisitions not only included blast waves of incident pressure, reflected pressure, and impulse, but also included displacement, acceleration, and strains at steel, concrete, PS tendon. The results can be used as basic research references for related research areas, which include protective design and blast simulation under blast loading.

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.4
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• pp.298-306
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• 2016

Planting date shift is one of the means of adapting to climate change in Kimchi Cabbage growers in major production areas in Korea. This study suggests a method to estimate the potential yield of Kimchi Cabbage based on daily temperature accumulation during the growth period from planting to maturity which is determined by a plant phenology model tuned to Kimchi Cabbage. The phenology model converts any changes in the thermal condition caused by the planting date shift into the heat unit accumulation during the growth period, which can be calculated from daily temperatures. The physiological maturity is estimated by applying this model to a variable development rate function depending either on growth or heading stage. The cabbage yield prediction model (Ahn et al., 2014) calculates the potential yield of summer cabbage by accumulating daily heat units for the growth period. We combined these two models and applied to the 1km resolution climate scenario (2000-2100) based on RCP8.5 for South Korea. Potential yields in the current normal year (2001-2010) and the future normal year (2011-2040, 2041-2070, and 2071-2100) were estimated for each grid cell with the planting dates of July 1, August 1, September 1, and October 1. Based on the results, we divided the whole South Korea into 810 watersheds, and devised a three - dimensional evaluation chart of the time - space - yield that enables the user to easily find the optimal planting date for a given watershed. This method is expected to be useful not only for exploring future new cultivation sites but also for developing cropping systems capable of adaptation to climate change without changing varieties in existing production areas.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.28 no.4
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• pp.321-340
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• 2017

The purpose of this study is to design a teaching model applying a problem-based learning model and to analyze the educational benefits that students felt. This study initiated a problem-based learning model from an analysis of existing studies. Through the consultation of experts, the scenario was modified. The problem was designed according to the design stage activity (problem analysis, PBL class suitability judgment, contents analysis, learner analysis, environment analysis, PBL operating environment decision, PBL class) and Strategic Design (problem situation design, learning resource design, Facilitation design, operational strategy design, evaluation design, PBL operating environment design). Based on the initial scenarios, the researcher analyzed the results of the problem - based learning through learners' reflective diaries. The researcher was able to confirm that the critical thinking and creativity were improved in the first PBL problem situation, and the method for smooth communication and cooperation was utilized. The results on analyzing the effects of education about the first problem-based learning and students' opinions about modification will be used for the second revision and supplement of the course design. This study introduces a case of PBL course development and expects further application and research.

• Journal of Korean society of Dental Hygiene
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• v.4 no.1
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• pp.119-132
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• 2004

The purpose of this study was to introduce PBL to dental hygienist education in an effort to raise a question about the inauthentic and inappropriate curriculum. PBL is one of learning methods to enhance the problem-solving ability of learners, and it's attempted to develop a PBL package focusing on dental hygienist roles to lay the foundation for producing competent and expert dental hygienists with a good problem- solving ability. The literature concerned was reviewed from November 2002 through January 2003 to determine whether or not PBL was applicable to dental-hygienist course, and that turned out to be effective for dental hygienist education. And then a PBL package was developed to train students to be knowledgeable and have a knowhow and excellent problem-solving skills. The characteristics of the PBL package could be described as follows: First, that focused on dental hygienist roles to serve the purpose of this study to remedy the current unrealistic and improper curriculum and improve the problem-solving skills of learners. Second, time factor was taken into account. In this four-week course for two credits, there are four classes a week, and it's required to take six or eight weeks to apply the PBL package, which is expected to demotivate students. Therefore, it's planned to conduct more weekly classes to make a proper progress. Third, a wide variety of teaching aids were put to use, and learner would be encouraged to be more interactive and utilize teaching aids properly, and eventually, they could have an opportunity to better express themselves. Fourth, online real-time learner discussion would be attended by this researcher. Learners would have a discussion in real time in the Internet cafe chat room, and different discussion time would be allocated to each team. This researcher would take part in each team's discussion once or more. Fifth, learners would prepare one or more journal(s) about four-hour Internet cafe learning. They have to make it twice a week at least, and it would be a good opportunity for learners to look back on themselves and their teams, and their learning effect would be greater. Specific rules were presented to help them make a successful self-examination. Sixth, there are some spaces in the lower part of objective test sheets to have students describe why they make a particular answer choice. They would be asked to depict the reason of their prior evaluation and lecture assessment especially because their responses would be important for more successful discussion and feedback. Seventh, problem-solving approach was designed to attain learning objectives, stimulate the creative thinking of learners and help them share a more systematic discussion. That would serve as a secondhand guide not to make them digress when they discuss by using information they acquire from a scenario presented in class.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.725-731
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• 2020

This study analyzed the impact of increasing orange imports on the domestic fruit markets, focusing on the period January to May when oranges were imported and sold intensively after implementation of the Korea-US FTA. In this study, only citrus fruits that compete with U.S. oranges were limited to domestic fruits; of these, Hallabong, which is consistent with consumption of U.S. oranges, was selected as an analysis target. A dynamic recursive simulation model was established to evaluate the ex-post effects of the Korea-U.S. FTA, and to conduct mid and long-term forecasts for the Hallabong market. In addition, major policy simulations were performed on the Hallabong market to assess the effect of each scenario. The ex-post impact evaluation reveals that between December and February, Hallabong had no effect on the seasonal tariff of oranges. However, from 2012 to 2017, the actual import decreased by 21.9 billion won annually due to the TRQ, with the accumulated 6-year decrease being 131.5 billion won. Major policy simulation analysis shows that the change in the unit cost of import due to the U.S orange crop and the increase of Hallabong export will help in expanding the market, and thus effectively increase income.

• Journal of Navigation and Port Research
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• v.33 no.1
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• pp.9-19
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• 2009

This paper describes empirical approach methodology for the quantitative risk assessment of maritime transportation accident (MTA) of a merchant ship. The principal aim of this project is to estimate the risk of MTA that could degrade the ship safety by analyzing the underlying factors contributing to MTA based on the IMO's Formal Safety Assessment techniques and, by assessing the probabilistic risk level of MTA based on the quantitative risk assessment methodology. The probabilistic risk level of MTA to Risk Index (RI) composed with Probability Index (PI) and Severity Index (SI) can be estimated from proposed Maritime Transportation Accident Model (MTAM) based on Bayesian Network with Bayesian theorem Then the applicability of the proposed MTAM can be evaluated using the scenario group with 355 core damaged accident history. As evaluation results, the correction rate of estimated PI, $r_{Acc}$ is shown as 82.8%, the over ranged rate of PI variable sensitivity with $S_p{\gg}1.0$ and $S_p{\ll}1.0$ is shown within 10%, the averaged error of estimated SI, $\bar{d_{SI}}$ is shown as 0.0195 and, the correction rate of estimated RI, $r_{Acc}$(%), is shown as 91.8%. These results clearly shown that the proposed accident model and methodology can be use in the practical maritime transportation field.

• Journal of Korea Water Resources Association
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• v.50 no.3
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• pp.181-190
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• 2017

Population congestion and increasing porosity caused by urbanization and increasing rainfall intensity are the main reasons for urban inundation damage. In order to reduce the damage to urban flooding, it is necessary to take a inundation analysis model that can be considered the topographic impact (i.e., building and road) and simulate the detailed inundation areas. In this study, Grid based Inundation Analysis Model (GIAM) is developed using a two-dimensional shallow water equations. The study area is Gangnam basin, with a surface area of $7.4km^2$, which includes 5 drainage areas such as Nonhyun, Yeoksam, Seocho 1, 2, and 3. EPA SWMM5 is used for simulating the overflows at each manhole. GIAM model is constructed to allow for simulating a inundation area with 6 m grid size. The inundation analysis is conducted in two heavy rainfall events (Sep. 21, 2010 and July 27, 2011) for the model evaluation. The accuracy of the simulated inundation area is calculated 0.61 and 0.57 at POD index using the historical flooded area report. The developed model will be used as a tool for analyzing the flood prone areas based on rainfall scenario, and a tool for predicting the detailed inundation area in the real-time.