• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.2
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• pp.36-49
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• 2016

A subway system is one of the major transportation modes at a metropolitan area. When it meets the other lines, the metro station, so-called transferring station, is usually threatened by severe pedestrian congestion and safety issue of transit users including the transportation vulnerable. Although transportation planners forecast travel demand at the beginning, it is not easy to predict pedestrian flows precisely for a long term if land use plans have dramatically changed. Due to expensive costs, structural extension of metro stations is limited. Therefore, it requires efficient and technical improvements as meeting the demand of pedestrian and physical characteristics. In this study, the core mechanism of pedestrian movement-based simulation model was introduced and evacuation scenarios were analyzed with the developed model. As a result, the multiple optimal routes for unexpected events at the solid space of the multiple stories are easily searched through the simulator and in the case of Sadang Station, travel time can be reduced by 60% when the evacuation information and intuitive design are provided.

• Journal of the Korean Society of Safety
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• v.34 no.5
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• pp.144-152
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• 2019

According to the National Police Agency, point-to-point speed enforcement system is being installed and operated in 97 sections across the country. It is more effective than other enforcement systems in terms of stabilizing the traffic flow and inhibiting the kangaroo effect. But it is only 5.1% of the total enforcement systems. The National Police Agency is also aware that its operation ratio is very low and it is necessary to expand point-to-point speed enforcement system. Hence, this study aims to provide the expansion basis of the point-to-point speed enforcement operation through analysis of the quantitative effects and development the accident prediction model. Firstly, this study analyzed the effectiveness of point-to-point speed enforcement system. Naive before-after study and comparison group method(C-G Method) were used as methodologies of analyzing the effectiveness. The result of using the naive before-after study was significant. Total accidents, EPDOs and casualty crashes decreased by 42.15%, 70.64% and 45.30% respectively. And average speed and the ratio of exceeding speed limit decreased by 6.92% and 20.50%p respectively. Moreover, using the C-G method total accidents, EPDOs and casualty crashes decreased by 31.35%, 66.62% and 10.04% respectively. And average speed and the ratio of exceeding speed limit decreased by 3.49% and 56.65%p respectively. Secondly, this study developed a prediction model for the probability of casualty crash. It was dependant on factors of traffic volume, ratio of exceeding speed limit, ratio of heavy vehicle, ratio of curve section, and presence of point-to-point speed enforcement. Finally, this study selected the most danger sections to the major highway and evaluated proper installation sections to the recent installation section by applying the accident prediction model. The results of this study are expected to be useful in establishing the installation standards for the point-to-point speed enforcement system.

• Nuclear Engineering and Technology
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• v.19 no.2
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• pp.85-98
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• 1987

To analyze the aerosol dynamics in severe accidents of LMFBR, a new computer code entitled MCAD (Multicomponent Aerosol Dynamics) has been developed. The code can treat two component aerosol system using relative collision probability of each particles as sequences of accident scenarios. Coagulation and removal mechanisms incorporating Brownian diffusion and gravitational sedimentation are included in this model. In order to see the effect of particle geometry, the code makes use of the concept of density correction factor and shape factors. The code is verified using the experimental result of NSPP-300 series and compared to other code. At present, it fits the result of experiment well and agrees to the existing code. The input variables included are very uncertain. Hence, it requires uncertainty and sensitivity analysis as a supplement to code development. In this analysis, 14 variables are selected to analyze. The input variables are compounded by experimental design method and Latin hypercube sampling. Their results are applied to Response surface method to see the degree of regression. The stepwise regression method gives an insight to which variables are significant as time elapse and their reasonable ranges. Using Monte Carlo Method to the regression model of LHS, the confidence level of the results of MCAD and their variables is improved.

• Science of Emotion and Sensibility
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• v.22 no.2
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• pp.83-100
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• 2019

The purposes of this study are to identify the meaning of the geometrical patterns preferred by ancient Korean peoples and to classify them into some groups by their similarity. We investigated various patterns found on clothing and relics from GoJoseon to Goguryeo period, and utilized secondary sources such as history articles, Internet materials and photo and analyzed the associations of the varied patterns found in pottery, handicrafts, and clothing with the ancient cultures. We found the letters (ㅇ, ㅁ, and ㅅ of Korean alphabet, Hangul) preferred by ancestors who worshipped nature to identify the significations attached by them to particular patterns. The results confirm the following: first, the circle pattern indicated the sun, moon, stars in the sky, a bronze mirror, and a man's face. Circles and ovals were also observed to represent the individual souls of the clan or community. Second, square patterns symbolized the land and the patterns that signified the wellbeing of family and the country. Oblique rectangles were more frequently used as they represented a double use of the triangle, a shape that implied mystic power. Third, triangle symbolized regeneration, power, and humanity. While the Neolithic Age jade remnants of hair combs appear not to be irrelevant to the process of comb-shaped pottery production of the time, many fine comb-like lines may be found on bronze mirrors. Through its review of the glorious designs inherited from and established by ancient ancestors, the present research endeavor may help in identifying the spirits and traditions of Korean history.

• Convergence Security Journal
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• v.21 no.1
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• pp.177-189
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• 2021

Defense R&D is a key process for securing weapons systems determined by mid- and long-term needs to cope with changing future battlefield environments. In particular, the test and evaluation provides information necessary to determine whether or not to switch to mass production as the last gateway to research and development of weapons systems and plays an important role in ensuring performance linked to the life cycle of weapons systems. Meanwhile, if you look at the recent changes in the operational environment of the Korean Peninsula and the defense acquisition environment, you can see three main characteristics. First of all, continuous safety accidents occurred during the operation of the weapon system, which increased social interest in the safety of combatants, and the efficient execution of the limited defense budget is required as acquisition costs increase. In addition, strategic approaches are needed to respond to future battlefield environments such as robots, autonomous weapons systems (RAS), and cyber security test and evaluation. Therefore, in this study, we would like to present strategies for improving the testing and evaluation of weapons systems by considering the characteristics of the security environment that has changed recently. To this end, the improvement strategy was derived by analyzing the complementary elements of the current weapon system operational test and evaluation system in a multi-dimensional model and prioritized through the hierarchical analysis method (AHP).

• (The) Korean Journal of Educational Psychology
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• v.22 no.2
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• pp.367-384
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• 2008

The purpose of this study was to develop picture testing instrument for measuring children's causal reasoning ability on events that can occur in daily life. The measurement instrument contains three domain of human development; haman behavior domain, human psychology domain, and natural/physical domain. Through this study, researchers designed a concept model based on theoretical framework and prior studies and investigated the reliability and validity of the measurement instrument which was developed in accordance with the concept model. For the empirical validation research, a pretest was conducted to 336 elementary school students in grade 2 to 4 in Seoul. Considering reliability and validity of the developed measurement instrument and factor loadings, researchers sorted out 18 questions. And then 18 question test and KICE Critical Thinking Ability Test was conducted to 509 elementary school students in grade 1 to 4 in Seoul. According to the result of the tests, the researchers sorted out final 12 questions. The Cronbach's alpha, reliability of the children's causal reasoning ability test consisted of the final 12 question, was significant as .72. Also, the result of exploratory factor analysis showed that factors of this test were haman behavior domain, human psychology domain, and natural/physical domain. Moreover, the correlation between the KEDI Reasoning Ability Test(2003) scores and the scores of the test developed in the current study was significant as .55. Finally, the result of the analysis about children's grade differences, the development by discrepancy of age was significant in total points and that of each domain. The children's causal reasoning ability test developed by this study can be useful not only for the evaluation of children's thinking ability but also for screening of the handicapped children in thinking ability development.

• Environmental and Resource Economics Review
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• v.30 no.4
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• pp.607-625
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• 2021

The objective of this study is to estimate the relationship between CO₂ emissions and both nuclear power and renewable energy generation, and compare the cost efficiencies of nuclear power and renewable energy generation in reducing CO₂ emissions in Korea. The results show that nuclear power and renewable energy generation should be increased by 1.344% and 7.874% to reduce CO₂ emissions by 1%, respectively. Using the estimated coefficients and the levelized costs of electricity by source including the external costs, if the current amount of electricity generation is one megawatt-hour, the range of generation cost of nuclear power generation to reduce 1% CO₂ emissions is $0.72~$1.49 depending on the level of external costs. In the case of renewable energy generation, the generation cost to reduce 1% CO₂ emissions is $6.49. That is, to mitigate 1% of CO₂ emissions at the total electricity generation of 353 million MWh in 2020 in Korea, the total generation costs range for nuclear power is $254 million~$526 million for the nuclear power, and the cost for renewable energy is $2.289 billion for renewable energy. Hence, we can conclude that, in Korea, nuclear power generation is more cost-efficient than renewable energy generation in mitigating CO₂ emissions, even with the external costs of nuclear power generation.

• Journal of Practical Engineering Education
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• v.13 no.3
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• pp.515-532
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• 2021

The purpose of this study was to analysis of PBL for Korean Apprenticeship Program in Mechanical Engineering. The details of the study were as follows: First, the perception related to the PBL of Korean apprenticeship program was investigated. Second, the utilization and the operational difficulties of PBL for Korean Apprenticeship Program were investigated. Third, the supporting system for PBL was suggested. Research methods were literature research, questionnaire survey and FGI. The survey was conducted online from July 15 to August 14, 2021. A total of 515 respondents responded. A total of 108 in 515 respondents were in Mechanical Engineering. FGI conducted a total of 25 people who actual use PBL in the field of Korean Apprenticeship Program. Conclusions and suggestions based upon the result of this study are as follows. First, It is necessary to improve the utilization of PBL for Korean Apprenticeship Program in Industry. Second, PBL is necessary to apply optionally according to the job and field situation. Third, it is necessary to support system of evaluation for PBL in Korean Apprenticeship Program. Finally, related operation model and guideline need to be prepared for best practice.

• Journal of Service Research and Studies
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• v.12 no.3
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• pp.45-59
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• 2022

This study attempted to investigate how the transformational leadership perceived by flowers of telemarketing organizations. In particular, this study explored the moderating effect of followership in the relationship between transformational leadership and organizational performance. To verify the research model, 321 surveys collected from 10 domestic call centers were analyzed. Reliability, correlation, factor analysis, and hierarchical regression analysis were performed, and as a result of the analysis, it was found that the transformational leadership in the telemarketing organizations had a positive effect on organizational performance. In addition, it was confirmed that goal consistency, proactive participation, critical thinking, and team spirit, which are the four sub-variables of followership, all have a positive (+) effect on organizational performance, and both goal consistency and proactive participation moderate the relationship between transformational leadership and organizational performance. Considering the special working environment of telemarketing organizations, the results of this study suggest the need for a corporate educational role to increase transformational leadership and followership and the need to build environments by setting up an atmosphere for members to exercise follow-up, and opening up communication structures for members to follow.

• Journal of Science Education
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• v.46 no.2
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• pp.165-177
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• 2022

This study aims to develop a field trip program for the Hantan River geopark in Pocheon using Orion's field trip model. The selected learning sites were the Hwajeogyeon and Bidulginang Falls, famous geosites of the Hantan River geopark in Pocheon. The field trip program consisted of six preparatory units, two field trip units, and two summary units. The preparatory stage helped reduce the novelty space considering cognitive, psychological, and geographical factors. In the field trip stage, students acquire concepts linked to learning elements in the curriculum scientifically and encourage interest in science. In the summary stage, students organized the geological phenomena observed in the field and inferred the vicinity of the Pocheon Hantan River region. The field trip program was modified to give enough time for observation activities to increase students' interest in science and to connect concepts with learning elements in the curriculum in the outdoor learning phase to allow students' convergent thinking. Implementing the field trip program raises students' interest and attitude in science.