• Journal of Wetlands Research
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• v.18 no.3
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• pp.324-329
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• 2016

Constructed wetlands are widely applied in urban and rural areas for various purposes such as pollutants reduction, acquisition of eco-spaces and habitats, flooding reduction, acquisition of water resources and environmental education. Since the design of constructed wetlands utilizes ecosystems, special consideration must be given to ecological mechanisms, environmental mechanisms and hydrological mechanisms. To ensure the sustainable functionality of constructed wetlands, it is necessary to achieve stable flow rate and velocity, and remove sediments to ensure sufficient space for detention. To enhance the efficiency of constructed wetland sedimentation basins, this study determined the optimal position for baffle installation, and applied Computational Fluid Dynamics (CFD) to the cross-sectional design of wetlands. CFD analysis revealed that the decrease in flow velocity with baffle installation enhanced the efficiency of sedimentation of particulate matters. Vertical baffles had higher sedimentation efficiency than those with an inclined angle. When vertical baffles were installed in the sedimentation basin of a hybrid constructed wetland to reduce non-point source pollutants in urban areas, the average flow velocity within the basin decreased by 10~30%, while the sedimentation efficiency improved by 1.3~1.5 times. The application of CFD to constructed wetlands is expected to improve the cost efficiency of designing hybrid constructed wetlands with high removal efficiency.

• Journal of Convergence for Information Technology
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• v.10 no.1
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• pp.149-157
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• 2020

This study aimed to explore the change of engineering students' competencies through the havruta class. In the havruta class, engineering students' competencies were compared with pre-test and post-test. The research tool was developed by selecting learning readiness, academic self-efficacy, and communication ability as the learner's competence in the havruta class. Finally, 105 data were analyzed with SPSS 21.0 for windows. First, there was a statistically significant difference in learning readiness. Second, there was no statistically significant difference in academic self-efficacy. Third, there was a statistically significant difference in communication ability. It was found that there was a positive change of competencies in learning readiness ability and communication ability in the havruta class. Although the findings are difficult to generalize to all majors, these results will be a useful basis for instructors who want to apply the havruta class.

• Journal of Korea Society of Industrial Information Systems
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• v.22 no.4
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• pp.117-129
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• 2017

The Purpose of this Study is to Identify the Learning Modules of the National Competency Standard (NCS) Related to the Information Systems Development Curriculum of 4-year Colleges, to Explore the Possibility of Applying NCS to the Curriculum, and to Examine Implications. The Importance of 26 Competency Units in the Applied SW Engineering of NCS was Compared by Area Experts Composed of 14 Information Systems Developers and Professors of 7 Universities who Teach Software Engineering Subjects Through the Hierarchical Analysis Process (AHP). The Results of the Study as Follows. First, the Relative Importance of the Competency Elements was in order of 'Confirming the Requirements', 'Checking the UI Requirements', 'Designing the Physical Data Repository', 'Testing Developer Integration', and 'Fixing Developer Defects'. Second, while the Entry and Intermediate Level Developer Group Determined that the Competency Elements Related to the IS Development Implementation Stage is more Important, the Advanced IS Developer Groups Consider the Competency Elements Related to the Theory-oriented Design Stage as Important Competency. In Addition, the Group of College Professors was Found to Choose all the Practical and Theoretical Competency Elements that Two Developers Groups Considered Important. Implications of the Study Suggested that the Job Performance Competence and Quality of Education Related to IS Development can be Enhanced.

• Environmental Engineering Research
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• v.13 no.3
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• pp.131-135
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• 2008

In this study, Fe(VI) was employed as a multi-functional agent to treat the simulated industrial wastewater contaminated with Cu(II)-EDTA through oxidation of EDTA, decomplexation of Cu(II)-EDTA and subsequent removal of free copper through precipitation. The decomplexation of $10^{-4}\;M$ Cu(II)-EDTA species was performed as a function of pH at excess concentration of Fe(VI). It was noted that the acidic conditions favor the decomplexation of Cu(II)-EDTA as the decomplxation was almost 100% up to pH 6.5, while it was only 35% at pH 9.9. The enhanced degradation of Cu(II)-EDTA with decreasing the pH could be explained by the different speciation of Fe(VI). $HFeO_4^-$ and $H_2FeO_4$, which are relatively more reactive than the unprotonated species $FeO_4^{2-}$, are predominant species below neutral pH. It was noted that the decomplexation reaction is extremely fast and within 5 to10 min of contact, 100% of Cu(II)-EDTA was decomplexed at pH 4.0. However, at higher pH (i.e., pH 10.0) the decomplexation process was relatively slow and it was observed that even after 180 min of contact, maximum ca 37% of Cu(II)-EDTA was decomplexed. In order to discuss the kinetics of the decomplexation of Cu(II)-EDTA, the data was slightly fitted better for the second order rate reaction than the first order rate reaction in the excess of Fe(VI) concentration. On the other hand, the removal efficiency of free Cu(II) ions was also obtained at pH 4.0 and 10.0. It was probably removed through adsorption/coagulation with the reduced iron i.e., Fe(III). The removal of total Cu(II) was rapid at pH 4.0 whereas, it was slow at pH 10.0. Although the decomplexation was 100% at lower pH, the removal of free Cu(II) was relatively slow. This result may be explicable due to the reason that at lower pH values the adsorption/coagulation capacity of Fe(III) is greatly retarded. On the other hand, at higher pH values the decomplexation of Cu(II)-EDTA was partial, hence, slower Cu(II) removal was occurred.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.6
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• pp.681-689
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• 2019

Web usage pattern discovery is an advanced means by using web log data, and it's also a specific application of data mining technology in Web log data mining. In education Data Mining (DM) is the application of Data Mining techniques to educational data (such as Web logs of University, e-learning, adaptive hypermedia and intelligent tutoring systems, etc.), and so, its objective is to analyze these types of data in order to resolve educational research issues. In this paper, the Web log data of a university are used as the research object of data mining. With using the database OLAP technology the Web log data are preprocessed into the data format that can be used for data mining, and the processing results are stored into the MSSQL. At the same time the basic data statistics and analysis are completed based on the processed Web log records. In addition, we introduced the Apriori Algorithm of Web usage pattern mining and its implementation process, developed the Apriori Algorithm program in Python development environment, then gave the performance of the Apriori Algorithm and realized the mining of Web user access pattern. The results have important theoretical significance for the application of the patterns in the development of teaching systems. The next research is to explore the improvement of the Apriori Algorithm in the distributed computing environment.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.4
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• pp.765-773
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• 2017

With the end of the HFA (Hyogo Framework Action) in 2015, SFDRR (Sendai Framework for Disaster Risk Reduction) was adopted as a new agenda for disaster risk reduction at the 3th WCDRR (World Conference on Disaster Risk Reduction), held in March 2015. Continued understanding of the international agenda for reducing disaster risk is critical to disaster risk reduction at the national level as well as international level. Therefore, in this study, we analyzed major changes in the international agenda for disaster risk reduction as the transition from HFA to SFDRR, and analyzed South Korea's major achievements in the HFA and the implementation status of SFDRR in South Korea. In addition, SFDRR emphasizes the role of science and technology in policy making, and examined research trends in science and technology. 49.9% of the efforts were made to prevent the disasters during the disaster management stage, and plans related to priority 1 (40.4%) and 4 (35.8%) were mainly promoted. Science and technology research and development for disaster management were analyzed as active, but 79.7% of the tasks were related to priority 4, and it is necessary to develop all four priorities. Recently, disaster management using next-generation disaster prevention technologies such as satellite technology and big data is required, and it is expected that it will contribute effectively to mitigate disaster risk through establishment of education and policy to support it.

• Journal of Korea Technology Innovation Society
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• v.15 no.1
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• pp.47-75
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• 2012

Basic research have contributed to technological growth or economic growth in U.S. Specially recent studies say that universities also contribute to economic development through scientific activities like science research, education, technology transfers. But we can not assure whether scientific knowledge was connected to real technology or economic performance, and it is difficult to figure out the effect of scientific output. "What is the exact performance of scientific knowledge?" It is still obscure. In this context, this paper analyzes characteristics of the linkage of science and technology. Data are U.S. R&D expenditure, scientific articles, citation of articles in U.S. patents by fields and sectors. As a result, university sector has the most weight of the linkage of science and technology. But, in relative connection rate analysis, industrial sector's is stronger than any other sectors. In the field analysis, linkage of science and technology is very strong in Chemistry, Physics, Biological sciences fields. And recently the linkage was increased in the fields of Computer science, Agricultural science, Engineering. Finally, this paper supports funding policy or estimation policy of government to product of scientific knowledge. University sector is still important because it has the most weight of the linkage. Scientific knowledge of industrial sector is also important. The connection rate of industrial science is the strongest in all sectors. And this research classify the R&D type by science fields. Considering the differences of science fields is needed to product science knowledge effectively.

• Journal of Navigation and Port Research
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• v.39 no.6
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• pp.457-463
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• 2015

A gas turbine engine plays an important role as a prime mover that is used in the marine transportation field as well as the space/aviation and power plant fields. However, it has a complicated structure and there is a time delay element in the combustion process. Therefore, an elaborate mathematical model needs to be developed to control a gas turbine engine. In this study, a modeling technique for a gas generator, a PLA actuator, and a metering valve, which are major components of a gas turbine engine, is explained. In addition, sub-models are obtained at several operating points in a steady state based on the trial running data of a gas turbine engine, and a method for controlling the engine speed is proposed by designing an NPID controller for each sub-model. The proposed NPID controller uses three kinds of gains that are implemented with a nonlinear function. The parameters of the NPID controller are tuned using real-coded genetic algorithms in terms of minimizing the objective function. The validity of the proposed method is examined by applying to a gas turbine engine and by conducting a simulation.

• Journal of Korea Water Resources Association
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• v.55 no.10
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• pp.749-759
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• 2022

The paradigm of water cycle management in the watershed is changing due to the increase in abnormal climate phenomena caused by climate change and the increase in impervious area due to urbanization. Research is continuously underway based on Low Impact Development technology that can suppress water cycle distortion. In this study, factors that can reflect water cycle distortion were selected before applying LID, and the PSR index for each 148 watershed was calculated for the the Nakdonggang River basin. As of 1975, the PSR index is calculated by calculating the pressure index P, which represents the rate of change in impervious surface area to 2019, the phenomenon index S, which represents the rate of change in water cycle for each subwatershed, and the Low Impact Development area countermeasure index R. The lower PSR index value, the higher the priority management watershed, and the water cycle recovery priority management watershed was calculated in the order of 1, 2, 87, 90, 91, and 147. It is expected that the efficient application of low-impact development factors in accordance with the order of priority management of water cycle by subwatershed in the large area will contribute to the recovery of water cycle distortion.

• Korean Journal of Ecology and Environment
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• v.56 no.3
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• pp.196-206
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• 2023

Benthic attached diatoms (BADs), a major primary producer in lotic stream and river ecosystems are micro-sized organisms and require a highly magnified microscopic technique in the observation work. Thus, it is often not easy to ensure accuracy and precision in both qualitative and quantitative analyses. This study proposed a new technique applicable to improve quality control of aquatic ecosystem monitoring and assessment using BADs. In order to meet the purpose of quality control, we developed a permanent mounting slide technique which can be used for both qualitative and quantitative analyses simultaneously. We designed specimens with the combination of grid on both cover and slide glasses and compared their efficiency. As a result of observation and counting of BADs, the slide glass designed with the color-lined grid showed the highest efficiency compared to other test conditions. We expect that the method developed in this study could be effectively used to analyze BADs and contributed to improve the quality control in aquatic ecosystem health monitoring and assessment.