• Clean Technology
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• v.22 no.3
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• pp.190-195
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• 2016

The thermal decomposition of waste energetic materials such as TNT, RDX and composition B in a commercial rotary kiln has previously been carried out. As part of the demilitarization process, the thermal decomposition of homogeneous double base propellant (DB) used in M8 and consisting predominantly of nitrocellulose and nitroglycerine is examined with respect to a number of operating conditions. A single condensed phase reaction with 4 species and 365 gas phase reactions and 59 species are considered. Simulation results show the sensitivity of the thermal decomposition of DB with temperature and velocity. At relatively low velocity with constant inlet hot air temperature, temperature in the rotary kiln was found to be highest, 953 K and 1300 K for cases 3 and 6 respectively. Illustrating that optimum operating temperature can be achieved by controlling the inlet velocity without additional cooling systems.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.3
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• pp.149-156
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• 2011

This experimental design and response surface methodology (RSM) have been applied to the investigation of the electro-UV-ultrasonic complex process for the disinfection of E. coli in the water. The disinfection reactions of electro-UV-ultrasonic process were mathematically described as a function of parameters power of electrolysis ($X_1$), UV ($X_2$), and ultrasonic process ($X_3$) being modeled by use of the Box-Behnken technique, which was used for fitting 2nd order response surface model. The application of RSM yielded the following regression equation, which is empirical relationship between the residual E. coli number (Ln CFU) in water and test variables in coded unit: residual E. coli number (Ln CFU) = 23.69 - 3.75 Electrolysis - 0.67 UV - 0.26 Ultrasonic - 0.16 Electrolysis UV + 0.05 Electrolysis Ultrasonic + 0.27 $Electrolysis^2$ + 0.14 $UV^2$ - 0.01 $Ultrasonic^2$). The model predictions agreed well with the experimentally observed result ($R^2$ = 0.983). Graphical 2D contour and 3D response surface plots were used to locate the optimum range. The estimated ridge of maximum response and optimal conditions for residual E. coli number (Ln CFU) using 'numerical optimization' of Design-Expert software were 1.47 Ln CFU/L and 6.94 W of electrolysis, 6.72 W of UV and 14.23 W of ultrasonic process. This study clearly showed that response surface methodology was one of the suitable methods to optimize the operating conditions and minimize the residual E. coli number of the complex disinfection.

• Journal of the Korean Data and Information Science Society
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• v.26 no.6
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• pp.1175-1188
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• 2015

The Ministry of Education of Korea announced the university structural reform plans which reduces 160,000 of the university entrance quota during 10 years from January 2014. Because the reduction plans of entrance quota influence regional economy as well as students and universities, naive evidence of the Ministry of Education of Korea is disappointed. In this research, we forecast the total number of the university entrance exam candidate by 2032 including not only third grade high school students but also repeaters according to the 16 metropolises and provinces in Korea. We also forecast the regional university recruiting rate using the forecasts of the total number of the university entrance exam candidates. However, we can not make more realistic results because we can not apply the inter-regional movement of students to the forecast. In order to handle this limitation, we first estimated the rank of the whole 7,277 departments of all universities in Korea and assigned the quotas according to the estimated rank for each departments and then we calculated the local university recruiting rate. The estimated the university recruiting rates of 16 metropolises and provinces can provide more noticeable results of characteristics and problems than that of nationwide.

• Journal of the Korean earth science society
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• v.43 no.2
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• pp.324-347
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• 2022

Geological information on the Korean Peninsula plays a significant role in science education because it provides a basic knowledge foundation for public use and creates an opportunity to learn about the nature of geology as a historical science. In particular, the Mesozoic Era, when the Korean Peninsula experienced a high degree of tectonic activity, is a pivotal period for understanding the geological history of the Korean Peninsula. This study aimed to analyze whether content regarding the geology of the Mesozoic Era are reliably and consistently presented in the 'Geology of the Korean Peninsula' section of Earth Science II textbooks based on the 2015 revised curriculum. Four textbooks for Earth Science II were analyzed, focusing on the sedimentary strata, tectonic movement, and granites of the Mesozoic Era. The analysis items were terms, periods, and rock distribution areas. The consistency within and among textbooks and of textbooks and scientific knowledge was analyzed for each analysis item. Various inconsistencies were found regarding the geological terms, periods, and rock distribution areas of the Mesozoic Era, and suggestions for its improvement were discussed based on these inconsistencies. It is essential to develop educational materials that are consistent with the latest scientific knowledge through collaboration between the scientific and educational communities.

• Hwankyungkyoyuk
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• v.6 no.1
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• pp.199-209
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• 1994

To investigate the trends in environmental education research of foreign countries, the paper published in the Journal of Environmental Education from 1984 to 1992 were analyzed. Major results of this study are as follows: 1. Total number of the paper analyzed was 178 and the average numbers of paper published per year were similar. 2. Researchers' majors were various. 3. The major targets of the researches in environmental education were school students. 4. Questionnaire was used in many researches and the main area of researches was strategy for environmental education. 5. Major type of research was survey and the main area of researches was strategy for environmental education. 6. The affective domain was highly concerned in environmental education researches.

• Journal of the Korea Convergence Society
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• v.10 no.2
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• pp.75-81
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• 2019

The purpose of this study was to perform a convergence study for the investigation of the trend of research topics related to thyroid cancer in Korea. We collected related research papers from DBpia and employed LDA-based topic model. In result, we identified four research topics, each of which concerns "Surgery", "Disease aggressiveness", "Survival analysis", and "Well-being of patients". With multinomial logistic regression, we found significant time trend, where "Surgery"-related topic was popular before 2000, topics regarding "Disease aggressiveness" and "Survival analysis" were frequently addressed in the 2000s, and "Survival analysis" and especially "Well-being of patients" have been pursued since 2010. The findings would serve as a reference guide for research directions. Future work may examine whether the recent change in research topics is observed in other diseases.

• Journal of the Korea Society for Simulation
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• v.27 no.4
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• pp.9-18
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• 2018

This paper proposes new algorithms of accessibility indices to analyze the connectivity of the Korean highway network. First of all, we find a transportation network that presents Korea's highway network in graphs in 2011 and 2017. And we analyze and compare the nation's highway network in 2011 and 2017 using concepts such as associated number, the relative distance, the accessibility, the degree of connectivity, the index of dispersion, the diameter of graph theory. To do this, an algorithm is presented which can easily obtain various accessibility indices from a given transportation network. Using the simulation results of this study, we can find city that is the center of traffic in the highway transportation network. In addition, cities that are included in the network but are relatively underdeveloped can be found and used as basic data for enhancing the connectivity of the nationwide traffic in the future. Moreover, the proposed algorithms of accessibility indices, which are modeled on highway transport networks, can help identify the accessibility space structure of each city and provide criteria for efficient and reasonable selection of alternatives in various regional planning processes, including transportation.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.23 no.4
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• pp.204-217
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• 2018

This study proposes a cost-effective method to monitor coastal environments using e-Navigation-implemented domestic and international ferries, and to analyze big data of records such as wind, temperature, salinity, waves, and currents that are gathered through e-Navigation system. First, we present the concept and architecture of e-Navigation operation system based on the General Information Center on Maritime Safety and Security. Then, the marine observation system that can be applied to ferries operating in our nation's territory is discussed. Analytical methods, such as spatio-temporal mixed effects model, ensemble method, and meshfree method, in handling real-time big data obtained by the e-Navigation observing system are then explained in detail. This study will support the implementation of the Korean e-Navigation project that focuses on the safety of small vessels such as coasters and fishing vessels.

• Journal of the Korean Society for information Management
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• v.36 no.1
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• pp.169-190
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• 2019

This study aims to identify the effects of teachers' recognition and application of 2015 revised national curriculum on their educational information needs in high schools. Several in-depth interviews and a questionnaire survey with the teachers, who were in charge of teaching common courses, such as Korean language, mathematics, English, social studies, and science, in general public high schools in Incheon, were executed for the purpose. As a result, the teachers' recognition and application affected their educational information needs in part. Especially, new demands on small sized copies and learning information sources were identified which were related to the application of 2015 revised national curriculum. Based on the results, we proposed several improvements of school library operations, such as small sized local consortium for sharing resources and providing referral services, in order to strengthen the gateway role of school libraries.

• Information Systems Review
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• v.22 no.4
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• pp.41-58
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• 2020

This study addresses the issue of which factors make domestic works have turnover intention. To pursue this research issue, we utilized a public database "2017 Occupational Migration Path Survey", administerd by Korea Employment Information Service (KEIS). Decision tree method was applied to extract crucial factors influencing workers' turnover intention. They include 'the degree of matching the level of education with the level of work', 'the possibility of individual development', 'the job-related education and training', 'the promotion system', 'wage and income', 'social reputation for work' and 'the stability of employment'.