• Economic and Environmental Geology
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• v.54 no.1
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• pp.21-33
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• 2021

The purpose of this study is to determine the order of priority for the use of amendments, matching the optimal amendment to the specific site in Korea. This decision-making process must prioritize the stabilization and economic efficiency of amendment for heavy metals and metalloid based on domestic site contamination scenarios. For this study, total 5 domestic heavy metal contaminated sites were selected based on different pollution scenarios and 13 amendments, which were previously studied as the soil stabilizer. Batch extraction experiments were performed to quantify the stabilization efficiency for 8 heavy metals (including As and Hg) for 5 soil samples, representing 5 different pollution scenarios. For each amendment, the analyses using XRD and XRF to identify their properties, the toxicity characteristics leaching procedure (TCLP) test, and the synthetic precipitation leaching procedure (SPLP) test were also conducted to evaluate the leaching safety in applied site. From results of batch experiments, the amendments showing > 20% extraction lowering efficiency for each heavy metal (metalloid) was selected and the top 5 ranked amendments were determined at different amount of amendment and on different extraction time conditions. For each amendment, the total number of times ranked in the top 5 was counted, prioritizing the feasible amendment for specific domestic contaminated sites in Korea. Mine drainage treatment sludge, iron oxide, calcium oxide, calcium hydroxide, calcite, iron sulfide, biochar showed high extraction decreasing efficiency for heavy metals in descending order. When the economic efficiency for these amendments was analyzed, mine drainage treatment sludge, limestone, steel making slag, calcium oxide, calcium hydroxide were determined as the priority amendment for the Korean field application in descending order.

• Journal of The Korean Society of Agricultural Engineers
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• v.59 no.1
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• pp.45-55
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• 2017

Climate change causes changes in rainfall patterns, temperature and drought frequency. Climate change impact influences on water management and crop production. It is critical issue in agricultural industry. Rice is a staple cereal crop in South Korea and Korea uses a ponding system for its paddy fields which requires a significant amount of water. In addition, water supply has inter-relationship with crop production which indicates water productivity. Therefore, it is important to assess overall impacts of climate change on water resource and crop production. A water footprint concept is an indicator which shows relationship between water use and crop yield. In addition, it generally composed of three components depending on water resources: green, blue, grey water. This study analyzed the change trend of water footprint of paddy rice under the climate change. The downscaled climate data from HadGEM3-RA based on RCP 8.5 scenario was applied as future periods (2020s, 2050s, 2080s), and historical climate data was set to base line (1990s). Depending on agro-climatic zones, Suwon and Jeonju were selected for study area. A yield of paddy rice was simulated by using FAO-AquaCrop 5.0, which is a water-driven crop model. Model was calibrated by adjusting parameters and was validated by Mann-Whitney U test statistically. The means of water footprint were projected increase by 55 % (2020s), 51 % (2050s) and 48 % (2080s), respectively, from the baseline value of $767m^2/ton$ in Suwon. In case of Jeonju, total water footprint was projected to increase by 46 % (2020s), 45 % (2050s), 12 % (2080s), respectively, from the baseline value of $765m^2/ton$. The results are expected to be useful for paddy water management and operation of water supply system and apply in establishing long-term policies for agricultural water resources.

• 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.

• The KIPS Transactions:PartC
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• v.9C no.5
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• pp.699-708
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• 2002

Since various terminals and different networks get involved in playing of a multimedia presentation, the case that the presentation QoS at a destination should be different from the QoS of multimedia data at a source occurs frequently. For playing the multimedia presentation, the multimedia data at a source should be transcoded into the multimedia data satisfying the QoS required at the terminal. The problem of generating the transcoding path is that, for a given multimedia presentation, different transcoding paths depending the terminal and networks should be generated. That is, a fixed transcoding path cannot be applied to a multimedia presentation. Instead, whenever the terminal and network to play the presentation get determined, a proper transcoding path should be regenerated automatically. In this paper, the algorithm for generating the transcoding path and the method for checking the playability of the generated path are proposed. The generating algorithm adopted the technique of Context Free Grammar in describing the set of transcoding resources and a user's transcoding rules in order to utilize the well-known compiler techniques. For the playability check, a method of computing the transcoding time and the delay time between data units are proposed. Finally all the proposed methods were implemented in the stream engine, called Transcore and the presentation-authoring tool, called VIP, we had developed. And the test results with a sample scenario were presented at the last.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.1
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• pp.107-113
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• 2009

This study has been conducted for the long-term riverbed change prediction on Geum River and Miho Stream surrounding the planned Multifunctional Administrative City and the neighboring regions by the construction of a small dam. Based on the analysis of vertical riverbed changes of the cross-sectional data for the years 1988, 2002 and 2007, minimum bed elevation significantly decreased in both Geum River and Miho Stream in 2007 as compared to 1988. Compared to 2002, however, a slight elevation change was observed. To make a long-term prediction on riverbed changes by the construction of a small dam, a one dimensional HEC-RAS 4.0 model has been used. By the fixed bed model test, the water levels were calibrated. By using the cross-sectional data of 1988 and 2002, verification was conducted under a movable bed model. According to the prediction of riverbed changes for each scenario with varying height of small dam, minor impact is expected around Miho Stream while major impact is expected around Geum River by 2017, as the small dam height increases. If the small dam is 7m-high, for example, it's been simulated that 1.59m deposition would be expected around the upper stream of Miho Stream Confluence while 1.98m scour would be expected around the downstream of the small dam.

• Tunnel and Underground Space
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• v.31 no.6
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• pp.469-479
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• 2021

As a material for preventing spalling of concrete, the effectiveness of PP fiber has already been confirmed. However, it is necessary to consider the maximum temperature that occurs during a fire, and to solve the mixing problem and the strength reduction problem that occur depending on the mixing amount. In this study, the fire resistance performance of tunnel segment linings according to the PP fiber content and air volume under the RABT fire scenario was investigated. As a result, no spalling or cross-sectional loss occurred in all test specimens, and when the PP fiber content was small, the maximum temperature was relatively high and the maximum temperature arrival time was also fast. On the other hand, no trend was found for the maximum temperature and arrival time according to the difference in air volume. In the internal temperature distribution results for the PP fiber mixing amount of 0.75, 1.0, 1.5, and 2.0 kg/m³, the results of 0.75 and 1.0 kg/m³ showed similar temperature distribution, and the results of 1.5 and 2.0 kg/m³ were similar. It was confirmed that the internal temperature distribution tends to decrease at the same depth when the amount of PP fiber mixed is large, and it was confirmed that a remarkable difference occurred from the results of 1.0 kg/m³ and 1.5 kg/m³ of PP fiber mixed amounts.

• Journal of Biomedical Engineering Research
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• v.44 no.6
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• pp.363-376
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• 2023

According to the COVID-19, development of various medical software based on IoT(Internet of Things) was accelerated. Especially, interest in a central software system that can remotely monitor and control ventilators is increasing to solve problems related to the continuous increase in severe COVID-19 patients. Since medical device software is closely related to human life, this study aims to develop central monitoring system that can remotely monitor and control multiple ventilators in compliance with medical device software development standards and to verify performance of system. In addition, to ensure the safety and reliability of this central monitoring system, this study also specifies risk management requirements that can identify hazardous situations and evaluate potential hazards and confirms the implementation of cybersecurity to protect against potential cyber threats, which can have serious consequences for patient safety. As a result, we obtained medical device software manufacturing certificates from MFDS(Ministry of Food and Drug Safety) through technical documents about performance verification, risk management and cybersecurity application.The purpose of this study is to conduct a usability assessment to ensure that ergonomic design has been applied so that the ventilator central monitoring system can improve user satisfaction, efficiency, and safety. The rapid spread of COVID-19, which began in 2019, caused significant damage global medical system. In this situation, the need for a system to monitor multiple patients with ventilators was highlighted as a solution for various problems. Since medical device software is closely related to human life, ensuring their safety and satisfaction is important before their actual deployment in the field. In this study, a total of 21 participants consisting of respiratory staffs conducted usability test according to the use scenarios in the simulated use environment. Nine use scenarios were conducted to derive an average task success rate and opinions on user interface were collected through five-point Likert scale satisfaction evaluation and questionnaire. Participants conducted a total of nine use scenario tasks with an average success rate of 93% and five-point Likert scale satisfaction survey showed a high satisfaction result of 4.7 points on average. Users evaluated that the device would be useful for effectively managing multiple patients with ventilators. However, improvements are required for interfaces associated with task that do not exceed the threshold for task success rate. In addition, even medical devices with sufficient safety and efficiency cannot guarantee absolute safety, so it is suggested to continuously evaluate user feedback even after introducing them to the actual site.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.6
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• pp.666-671
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• 2023

As international environmental regulations on ship emissions are gradually strengthened, interest in electric propulsion and hybrid propulsion ships is increasing, and various solutions are being developed and applied to these ships, especially stabilization of the power system and system efficiency. The direct current distribution system is being applied as a way to increase the power. In addition, verification and testing of safety and performance of marine DC distribution systems is required. As a result of establishing a DC distribution test bed, verifying the performance of the DC distribution (variable speed power generation) system, and analyzing fuel consumption, this study applied a variable speed power generation system that is applied to DC power distribution for ships, and converted the power output from the generator into a rectifier. A system was developed to convert direct current power to connect to the system and monitor and control these devices. Through tests using this DC distribution system, the maximum voltage was 751.5V and the minimum voltage was 731.4V, and the voltage fluctuation rate was 2.7%, confirming that the voltage is stably supplied within 3%, and a variable speed power generation system was installed according to load fluctuations. When applied, it was confirmed through testing that fuel consumption could be reduced by more than 20% depending on the section compared to the existing constant speed power generation system.

• Journal of the Society of Disaster Information
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• v.17 no.4
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• pp.864-881
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• 2021

Purpose: This study aims is to provide a total care solution preventing disaster based on Big Data and AI technology and to service safety considered by individual situations and various risk characteristics. The purpose is to suggest a method that customized comprehensive index services to prevent and respond to safety accidents for calculating the living safety index that quantitatively represent individual safety levels in relation to daily life safety. Method: In this study, we use method of mixing AHP(Analysis Hierarchy Process) and Likert Scale that extracted from consensus formation model of the expert group. We organize evaluation items that can evaluate life safety prevention services into risk indicators, vulnerability indicators, and prevention indicators. And We made up AHP hierarchical structure according to the AHP decision methodology and proposed a method to calculate relative weights between evaluation criteria through pairwise comparison of each level item. In addition, in consideration of the expansion of life safety prevention services in the future, the Likert scale is used instead of the AHP pair comparison and the weights between individual services are calculated. Result: We obtain result that is weights for life safety prevention services and reflected them in the individual risk index calculated through the artificial intelligence prediction model of life safety prevention services, so the comprehensive index was calculated. Conclusion: In order to apply the implemented model, a test environment consisting of a life safety prevention service app and platform was built, and the efficacy of the function was evaluated based on the user scenario. Through this, the life safety index presented in this study was confirmed to support the golden time for diagnosis, response and prevention of safety risks by comprehensively indication the user's current safety level.

• The Korean Journal of Emergency Medical Services
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• v.22 no.1
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• pp.7-19
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• 2018

Purpose: With the purpose of educating and producing outstanding paramedics by enhancing their competencies, this study aimed to make policy suggestions to re-establish the education system and improve the national examination and the certification scheme. Methods: This study used focus group interviews and questionnaires to collect data. Totally, there were 277 subjects, including experts from the education and field. Data were collected from September 9 to 20, 2016, and analyzed using SPSS 22.0. Results: To strengthen the curriculum of paramedics, this study suggested 27 courses with 94 credits as the standardized curriculum and derived 9 core competencies of paramedics. For the national examination, this study suggested consolidating written test subjects, adding scenario questions to practical tests, and applying critical criteria to simple practical tests that performs a procedure, grading these tests on a pass/fail basis. In addition, this study suggested converting certification into license, reflecting paramedics' healthcare job characteristics. Conclusion: The quality of emergency medical services in Korea will improve when those with core competencies that originated from the standardized curriculum based on the results of this study acquire their certification through the national test scheme, and the certification management system creates a virtuous cycle to further enhance paramedics' professionalism.