• Journal of Engineering Education Research
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• v.11 no.1
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• pp.85-100
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• 2008

The purpose of this study is development of 'F1 in Schools Program' for elementary school student and validation of the program. Fifteen students were originally chosen from the W elementary school in Cheongju, Chungcheogbuk-Do. The children were tested on their understanding of science and 'F1 in Schools Program'. After developing the 'F1 in Schools Program', it was used in the classroom to evaluate applicability and to examine the responses from students, parents and schools. The program consists of 60 classes and the time of each class is 40 minutes. This study was conducted for 10 days from January 22nd, 2007 to February 2nd, 2007. CAD(Computer Aided Design), CFD(Computation Fluid Dynamics), CAM(Computer Aided manufacturing) and CNC Machine were used in this study and proved to be good materials for students in that they increased the students' participation and imagination. However, the children's cognitive and creative abilities as well as manuals written in English hampered the process. Most students, parents, schools seemed to be satisfied with use of the program. However, the schools showed that there was not enough understanding of the program as a whole. The processes with which students build and inspect using the $CO_2$Model Car not only improves the processing of the model but also enhanced the students scientific understanding related to the car speed.

• Journal of Conservation Science
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• v.36 no.5
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• pp.351-367
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• 2020

The pigments of three old and new celestial charts folding screens(『Celestial Chart(Folding Screen)』 and 『Old and New Celestial Charts, Eight-Panel Folding Screen』 of National Folk Museum of Korea and 『Koudou-Nanboku-Ryousouseizu』 of National Diet Library of Japan) were analyzed to estimate their dating. It was estimated that the 『Celestial Charts(Folding Screen)』 was painted using traditional pigments from the Joseon dynasty such as azurite, indigo lake, malachite, atacamite, vermilion, iron oxide, cochineal, gamboge, orpiment, lead white, talc and soot. The green and blue colors of the 『Old and New Celestial Charts, Eight-Panel Folding Screen』 and 『Koudou-Nanboku-Ryousouseizu』 were painted using artificial inorganic pigments such as emerald green and ultramarine blue. These pigments were imported from Europe post the mid-19th century. In the 『Old and New Celestial Chart, Eight-Panel Folding Screen』, only artificial inorganic pigments were used for green and blue colors. However in the 『Koudou-Nanboku-Ryousouseizu』, emerald green and atacamite in green color, and ultramarine blue and indigo lake in blue color were used together. Based on both the results of pigment analysis and the study of star charts and inscriptions, the 『Celestial Charts(Folding Screen)』 was painted post mid-18th century. The 『Koudou-Nanboku-Ryousouseizu』 and 『Old and New Celestial Charts, Eight-Panel Folding Screen』 were painted after green and blue artificial pigments were imported in the mid-19th century. The 『Koudou-Nanboku-Ryousouseizu』 in which both traditional and western artificial pigments were used, can be dated earlier than the 『Old and New Celestial Chart, Eight-Panel Folding Screen』.

• Science of Emotion and Sensibility
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• v.20 no.1
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• pp.105-114
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• 2017

Nowadays, novel and innovative technology including 3D printers, internet of things (IoT), and wearable devices are rapidly emerging. As we must constantly keep up with the most recent trends, words like convergence, multidisciplinarity, and design revolution indeed define society today. Due to the expansion of such diverse technological, industrial, and academic convergence trends, the role of design is becoming evermore essential in development of products as well as creative services. Even the government is pushing towards a 'creative economy' by encouraging ICT convergence to create novel industries as well as advanced jobs. In order to adapt flexibly to such changes in global trends, a solid academic curriculum centered around 'ICT+Design' must be developed. In the current research, we analyzed various literature and benchmarked the major universities both domestic and foreign. Also we utilized a survey-based approach against subjects who are experts or design specialists working in environments related to industry and research. In our proposed integrated ICT+Design educational curriculum, students familiarize themselves with design perspectives and methodology to creatively carry out the course. Moreover, experts from design and ICT came together in an act of 'Radical Collaboration' in which they shared their unique 'Design Thinking' in order to promote understanding and cooperation. Furthermore, industry experts have also taken part as mentors in order to create a workplace-oriented course with various integrated projects. Most importantly, the course was designed so that in addition to research, students can really get hands-on with their ideas in the creativity-integrated workplace.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.6
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• pp.1121-1140
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• 1992

In metal cutting the shape of generated chip varies according to cutting conditions, characteristics of workpiece and geometry of cutting tool. The best surface roughness of machined workpiece is obtained when generating flow type contrinuous chip. If the generated chip is not broken, that is not only tangled workpiece and cutting tool, but also may give damage on the machined surface of workpiece or danger for a operator. The flow type continuous chip may bring the low productivity in high speed any heavy cutting, automatic machining process and non-human factory. There are two type of chip break process ; controlling cutting condition and using chip breaker. In present study we carried out the experiment on new type chip breaker compared with conventional type and proved the efficiency of a new type and showed the chip break condition to be applied in actual metal cutting. In the experiment SM 20 C as a workpiece material and WC as a tool material were used and cutting speed of 30-150m/min, feed of 0.071-0.210mm/rev and depth of cut of 1mm were applied as cutting condition. The results of the experiment are as follows : (1) The mechanism of chip curl can be explained more clearly by plastic flow of workpiece material and moment of shearing force. (2) The most effective radius of curled chip and flat distance from cutting edge is 2.0-2.5mm and 1.5mm in both types. (3) The effective inclination angle of chip break surface and side cutting edge angle are 30.deg.- 45.deg. and 20.deg. in conventional type, while the radius of arc surface, lower arc angle A, upper arc angle B and side cutting edge angle are 3mm, 20.deg.- 45.deg., 0.deg.- 45.deg. and 10.deg.- 20.deg. in new type. (4) The probability to be obtained 100% chip breaking ratio is much higher in new type than in conventional type.

• Journal of the Mineralogical Society of Korea
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• v.23 no.3
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• pp.243-250
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• 2010

Froth flotation of complex copper ore from Indonesia Jambi mine has been carried out to produce high-grade Cu concentrate. Since the ore contained minor Cu sulfides in addition to major Cu carbonate (malachite), copper concentrate was recovered by two-stage process of flotation, which consisted of copper sulfide flotation using xanthate followed by copper oxide flotation using oleic acid. The copper sulfide concentrate of 57.5% Cu grade with 9.5% recovery was obtained by copper sulfide flotation under conditions of 300 g/t collector (1 : 1 mixture of xanthate series Aero Promoter 211 and Aero Promoter 242) and pH 6.0 pulp. In subsequent copper oxide flotation on sink products, the concentrate of 30.8% Cu grade with 92.1% recovery was obtained under the conditions of oleic acid 300 g/t, AF65 50 g/t, pH 8.0 and 2 times cleaning. The flotation techniques which can achieve a Cu grade of 36.1% and a recovery of 92.1% have been developed from the two-stage process of flotation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.438-445
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• 2017

Tanzania has abundant copper deposits, but copper-metal extraction remains low there, owing to the lack of suitable copper recovery processes and insufficient funds for developing mining technologies. Accordingly, leaching and solvent extraction methods for the extraction of copper from copper ore were studied with a particular emphasis on developing a simple processing method for small-scale copper mining. Chrysocolla ore was used as the copper-bearing mineral and sulfuric acid was used as the leaching reagent. A maximum copper recovery of 95.1% was obtained when the particles in the sample were smaller than $53{\mu}m$, the concentration of 98%(w/w) sulfuric acid in the leaching solution was 5.0 g/L and the stirring rate was between 60 and 80 rpm. The highest selectivity of $Cu^2+$ in the solvent extraction was obtained using 15% LIX-70 in kerosene. In the pH range from 0.5 to 3.0, the efficiency of $Cu^2+$ extraction increased with increasing pH. However, at pH values higher than 3.0, other metal ions were extracted into the organic phase more readily than $Cu^2+$. The highest solvent extraction rate obtained was 96.5% at pH values of 2.0 and 3.0 using 15% LIX-70.

• Journal of Practical Engineering Education
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• v.13 no.2
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• pp.327-332
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• 2021

Materials used for education include SM20C, Al6061, and acrylic. SM20C materials are used a lot in certification tests and functional competitions as carbon steel, but they are also used in industrial sites. Al6061 is said to be a material that produces a lot of tools because it has lower hardness than carbon steel and is highly flexible. When practical guidance is given to students using acrylic materials, it is a material that causes vibration and tool damage due to excessive cutting. In this process, we examine how impact on the 5-axis equipment 2NC head can affect precision control. The weakest part of a five-axis equipment is the head that controls the AC axis. In the event of precision and cumulative tolerances in this area, the precision of all products is reduced. Thus, a key part of the 2NC head, the spindle housing was carried out using Al7075 T6 (U.S. Alcoasa) material and the entire body using FCD450 (spherical graphite cast iron). In the vibration and cutting process acting on these two materials, the analysis was carried out to determine the value of applying the force as a finite element analysis under extreme conditions. We hope that using these analytical data will help students see and understand the structure of 5-axis machining rather than 5-axis cutting.

• Journal of Korean Society of Forest Science
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• v.108 no.2
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• pp.224-232
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• 2019

The movement of fish to the upper and the lower parts of a mountain stream was investigated based on the installation of specific types of structures within the stream. The results indicated that as the flow rate increases after a rain, the height of the drop in an open-type structure, such as a concrete box, is decreased so that the floating fishes, such as the Chinese minnow fish, move relatively easily from the upper to the lower parts and from the lower to the upper parts of the stream. In contrast, the fishes released from an upper point of a wall-type structure with <1 m, such as rocks drop works and stone masonry for stream-grade stabilization, were trapped in the lower part of the stream and, even after the rainy season, it was difficult for the fish to move from the lower to the upper parts of the stream. In particular, the barrier-type structures ${\geq}3m$ limit the movement of fish, even when there are few drainage holes at the lower end of the dam, and there is no space for the fishes to communicate with each other, even when the flow rate is high; therefore, although the fish are active, they are restricted to move according to the type and characteristics of the structures. When installing structures in a mountain stream, the height of the structure must be low enough to allow the fish to communicate with each other or an open-type structure must be installed. The fish habitat and water conditions within the stream must be considered when designing the type and height of the in-stream structures.

• Convergence Security Journal
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• v.18 no.2
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• pp.167-177
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• 2018

Major countries, such as the U.S., UK and Germany have reformed their national intelligence systems in the face of transnational, asymmetric and comprehensive threats since September 11, 2001 and have strengthened the intelligence capacity involved in countering terrorism and WMD proliferation, right/left extremism threats. The Korean Moon Jae-in government is preparing a reform plan to eliminate illegal political intervention and abuse of power by the National Intelligence Service(NIS) and to rebuild it as an efficient national intelligence agency for national security. In discussing the reform direction of the NIS, it is necessary to discuss in detail whether adopting a separate model of intelligence agencies to restrict domestic intelligence activities of the NIS and concentrate on foreign intelligence activities or establish new domestic intelligence agencies. Second, as for the issue of transferring anti-Communism investigation authority of the NIS to the police, it needs to be carefully considered in terms of balancing the efficiency and professionalism of intelligence agency activity in the context of North Korea's continuous military provocation, covert operations and cyber threats. Third, it should strive to strengthen the control and supervision functions of the administration and the National Assembly to ensure the political neutrality of the NIS in accordance with the democratization era, to guarantee citizens' basic rights and to improve the transparency of budget execution.

• The Journal of Sustainable Design and Educational Environment Research
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• v.19 no.4
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• pp.26-39
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• 2020

This study analyzed the usage characteristics and requirements of students who are users of the middle school education space, and the following results were obtained: First, we could see that various types of classes were needed, such as lecture-style classes, team projects, and four-person consultation and discussion classes, in a way that helped to improve the desirable teaching patterns and learning ability. Second, the place where space was used during the break and the relationship between peers, revealed that most of them were in the classroom and the hallway, and the peer group was composed of three to eight people or more, that were active with various compositions. Third, a gym, library, toilet, stairway, cafeteria, nurse's office, and teachers' room appeared in the center of the building, indicating the need for a balanced layout. Fourth, physical education (dance) rooms, audiovisual rooms (performance rooms), workshops (personal creation), snack bar, rest area, spacious indoor square, and study rooms were needed as facilities that can help learning activities other than current facilities. These outcomes show that the existing classroom layout and space composition formats require some spatial restructuring.