• Journal of the Korean Magnetics Society
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• v.24 no.4
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• pp.123-127
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• 2014

We developed a digital 3-axis flux-gate magnetometer for magnetic field signal measurement from warship during demagnetizing and degaussing processes. For the magnetometer design, we considered following points; the distance between magnetic field measurement station and magnetometer located under sea is about several 100 m, the magnetometer is exposed to magnetic field of ${\pm}1mT$ during demagnetizing process, and magnetometer is located under the sea about 30 m depth. To overcome long distance problem, magnetometer could be operated on wide input supply voltage range of 16~36 V using DC/DC converter, and for the data communication between the magnetometer and measurement station a RS422 serial interface was employed. To improve perming effect due to the ${\pm}1mT$ during demagnetizing process, magnetometer could be compensated external magnetic field up to ${\pm}1mT$ but magnetic field measuring rang is only ${\pm}100{\mu}T$. The perming effect was about ${\pm}2nT$ under ${\pm}1mT$ external magnetic field. The magnetometer was tested water vessel with air pressure up to 6 bar for the sea water pressure problems. Linearity of the magnetometer was better than 0.01 % in the measuring range of ${\pm}0.1mT$ and noise level was $30pT/\sqrt{Hz}$ at 1 Hz.

• Macromolecular Research
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• v.10 no.3
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• pp.158-167
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• 2002

In order to endow with new bioactive functionality from small intestine submucosa (SIS) powder as natural source to poly (L-lactide) (PLA) and poly (lactide-co-glycolide) (PLGA) synthetic biodegradable polymer, porous SIS/PLA and SIS/PLGA as natural/synthetic composite scaffolds were prepared by means of the solvent casting/salt leaching methods for the possibility of the application of tissue engineered bone and cartilage. A uniform distribution of good interconnected pores from the surface to core region was observed the pore size of 40~500 ${\mu}{\textrm}{m}$ independent with SIS amount using the solvent casting/salt leaching method. Porosities, specific pore areas as well as pore size distribution also were almost same. After the fabrication of SIS/PLA hybrid scaffolds, the wetting properties was greatly enhanced resulting in more uniform cell seeding and distribution. Five groups as PGA non-woven mesh without glutaraldehyde (GA) treatment, PLA scaffold without or with GA treatment, and SIS/PLA (Code No.3 ; 1 : 12 of salt content, (0.4 : 1 of SIS content, and 144 ${\mu}{\textrm}{m}$ of median pore size) without or with GA treatment were implanted into the back of nude mouse to observe the effect of SIS on the induction of cells proliferation by hematoxylin and eosin, and von Kossa staining for 8 weeks. It was observed that the effect of SIS/PLA scaffolds with GA treatment on bone induction are stronger than PLA scaffolds, that is to say, in the order of PLA/SIS scaffolds with GA treatment > PLA/SIS scaffolds without GA treatment > PGA nonwoven > PLA scaffolds only with GA treatment = PLA scaffolds only without GA treatment for the osteoinduction activity. The possible explanations are (1) many kinds of secreted, circulating, and extracellular matrix-bound growth factors from SIS to significantly affect critical processes of tissue development and differentiation, (2) the exposure of SIS to GA resulted in significantly calcification, and (3) peri-implant fibrosis due to covalent bonding between collagen molecule by crosslinking reaction. In conclusion, it seems that SIS plays an important role for bone induction in SIS/PLA scaffolds for the application of tissue engineering area.

• Journal of the Korean Chemical Society
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• v.62 no.5
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• pp.398-411
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• 2018

The purpose of this study is to investigate the effects of research project activities using the science writing heuristic on science inquiry abilities and attitudes toward science in high school students. For this purpose, we conducted the research project activities using the science writing heuristic consisting of questioning, experimental design, observation, argument and evidence, reading, and reflection steps for 73 students of the second year of science core course in high school in Jeonnam. In order to analyze the effects of the program, we surveyed the scientific inquiry ability and attitude toward science, investigated the perception of the research project class applying science writing heuristic, and conducted interviews when there was difficulty in interpreting the results. And the results of this study are as follows. First, among the science inquiry abilities, the score of Reasoning, Hypothesis setting, Finding variables, Operational definition, Experimental design, Graphing and data interpretation, Generalization was significantly improved statistically (p<.05), but the score of Expectation was not statistically significant (p>.05). Second, among the attitudes toward science, the score of 'Leisure interest in science', 'Enjoyment of science lessons', 'Career interest in science' was significantly improved statistically (p<.05). And the score of 'Attitude to scientific inquiry' decreased but it's not significant statistically. The high school research project applying science writing heuristic had a positive effect on scientific inquiry ability and scientific attitude but it could be burden to students because it is led by students in a form different from general science class for a long time. And so continuous study on research project that minimize these disadvantages and maximize their merits is needed.

• Journal of Gifted/Talented Education
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• v.26 no.1
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• pp.77-99
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• 2016

The purpose of this study was to examine the effect of GI-STEAM program on leadership, creative personality, and learning flow of elementary Gifted Students. GI-STEAM program was the convergence model of Group Investigation that belongs to Co-learning and STEAM framework of learning criterion. The participants were 16 gifted students in a Korean elementary school located in Gyeong-gi province. The experimental design was one group pretest-posttest design. After a pretest on leadership, creative personality, and learning flow was conducted, classes were carried out as GI-STEAM program for the gifted student and a post-test was conducted. The study results of the class that was conducted twelve times for two weeks are as follows. First, Individual area of leadership is meaningfully developed in statistics after GI-STEAM program. The sub-domains of leadership, such as the communication, organization management, society commitment and teamwork showed a statistically significant improvement. Second, the domain of creative personality didn't show meaningful difference after GI-STEAM program. However, the aesthetic in the sub-domains of the creative personality showed a statistically significant improvement. Third, learning flow was meaningfully developed in statistics after GI-STEAM program. The sub-domains of the leadership, such as the balance between challenge and ability, integration with behavior and consciousness, concrete feedback and Autotelic experience showed a statistically significant improvement. In conclusion, GI-STEAM is an effective program for improving ability of communication, aesthetic sensibility, which are core competency of 'creative-convergence' gifted students. For this reason, it is highly considered that various programs applying GI-STEAM should be developed.

• Journal of Distribution Science
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• v.13 no.12
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• pp.73-84
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• 2015

Purpose - Various social issues have arisen since the beginning of the 21st century therefore, enterprises that disregarded social issues have become unsustainable, and social enterprises have appeared to address these issues. A social enterprise is a social mission-focused organization that uses a market-based strategy and has a vulnerable business structure. To be self-sustainable, a social enterprise should make consumers aware of the value that it provides and secure its profitability through consumer consumption. From this perspective, this study investigates the relationship between perceived value (utilitarian and hedonic) and loyalty, and examines how memory and attitudes play mediating roles between perceived value and loyalty. For these purposes, the author developed a structural model consisting of several variables. In this model, perceived value, which was utilitarian and hedonic, was proposed to affect the memory and attitudes toward social enterprise products, thus increasing loyalty. Therefore, memory and attitudes were proposed as core mediating variables between perceived value and loyalty. Research design, data, and methodology - To analyze the proposed model, data were collected from 582 respondents and analyzed using SPSS 21.0 and AMOS 21.0. To test unidimensionality and the nomological validity of the measures of each construct, we employed a scale refinement procedure. The results of the reliability test with Cronbach's α and confirmatory factor analysis warranted the unidimensionality of the measures for each construct. In addition, the nomological validity of the measures was warranted from the results of the correlation analysis. The result of the overall model analysis demonstrated a good fit (χ²=529.881, df=144, χ²/df=3.680, p-value=0.000, GFI=0.905, NFI=0.948, CFI=0.961, RMR=0.036, RMSEA=0.068). Results - The findings are summarized as follows. First, the hedonic and utilitarian value of social enterprise products had positive effects on memory and attitudes. Second, the hedonic value of social enterprise products more strongly affects memory and attitudes than utilitarian value. Third, memory and attitudes had positive effects on loyalty. Lastly, memory had a stronger effect on loyalty than attitudes. Conclusions - The purchase rate of social enterprises' products increases only if the products are included in the "information search" and "alternative evaluation" processes in consumers' purchase decision-making processes. Therefore, a social enterprise must actively promote the fact that it pursues a social value, and shares both the hedonic and utilitarian values of its products. Accordingly, because hedonic value has a more significant impact on a company and attitudes, a social enterprise should develop hedonic values for product consumption, thereby leading consumers who care about value consumption to purchase its products. Moreover, a social enterprise must maintain good memories and attitudes for consumers because memory does not change over time, although attitude does. The limitations of this study and suggestions for future research are as follows. This study viewed "consumer loyalty" as the success factor of social enterprises, thereby considers an "increase in sales" as the success factor. Therefore, in future studies, diverse factors, including social contribution and word-of-mouth intention, should be regarded. In addition, future studies need to thoroughly review and make assurances about the relationship between memory and attitude.

• Journal of Digital Convergence
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• v.8 no.1
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• pp.55-69
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• 2010

This thesis looks closely at the moderating effect of individual variables while we analyzed how corporate's ethics policies have influence on his ethical decision-making behaviors. The subjects of the research were full-time employees (n=211) in the Seoul metropolitan region. The research model was substantiated through statistical analysis of credibility and validity, correlation, variance, and moderated regression analysis (MRA). This study found that within an organization with a code of ethics, the level of enforcement of the code and the level of employee awareness of core values sought by the company determined the level of influence of the code on ethical decision making. In other words, internal factors exerted a greater influence than external evaluation of a corporation's ethical decision making practices and therefore, it is necessary for decision-making practices to be transparent and recognized by the members within an organization. The study also found that the employee's awareness about the long-term visions of the company at a higher level and the employees who have a locus of control to their members internally acted as independent variables as well as control variables on the ethical decision-making. In addition, there were great differences in the level of ethical decision-making among the variables used as controls, which means these differences were related to the individual variables. Accordingly, in order to get ethical decision-making practices at a higher level, a education & training program will be designed and implemented variously as considering on the particular characteristics of the control variables we used in this study.

• Journal of the Korean Geotechnical Society
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• v.20 no.9
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• pp.115-124
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• 2004

According to Sagong and Paik (2003), the side resistance of rock socketed drilled shafts is affected by rock quality, types, uniaxial compressive strength, and confining stress. Their approach based upon the Hoek-Brown criterion provides reasonable predictions of the side resistance. In this study, we propose an equation to calculate the side resistance considering size effects of the shafts and investigate the influence of drilled shaft diameter on the side resistance. A new method employs the modified Hoek-Brown criterion together with an empirical size effect of rock core. From the previous field tests, 12 pile load test results were collected and compared with prediction calculated from the equation proposed in this study. In a given condition, similar results between measurement and estimate are observed. From the parametric study on the GSI, confining stress, uniaxial compressive of intact rock and pile size, it is shown that uniaxial compressive strength is the most influential parameter on the side resistance. Though pile size shows the least influence on the resistance, the size effect is apparent as rock quality increases.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.480-480
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• 2008

Vacuum circuit breaker(VCB) is now emerging as an alternative of gas circuit breaker(GCB) which uses SF6 gas as insulating material whose dielectric strength is outstanding. But we have to reduce SF6 gas because SF6 gas is one of greenhouse gas and efforts to reduce greenhouse gas are now trend of the world. Therefore, we can say VCB is the optimal alternative of GCB because vacuum is environmentally friendly. The vacuum interrupter is the core part of VCB to interrupt arcing current. There are mainly two methods to extinguish arc. One is radial magnetic field (RMF) method and the other is axial magnetic field (AMF) method. We deals with RMF method in this paper. Compared with AMP, RMF arc quenching method has different principle to extinguish arc. In case of RMF method, pinch effect is much larger than AMF method. Because of pinch effect RMF type contact electrodes have the single large spot which is severly damaged and melted while AMF type contact electrodes have small and multiple spots which are slightly damaged and melted. To prevent contact electrode being damaged and melted from high temperature-arc, RMF method uses Lorentz force to move arc. In this paper we calculated and compared the arc driving force of two cases and we analyzed the force acting on each part of arc by means of commercial finite element method software Maxwell 3D. They have 3petals and we considered two cases. One is the case when fixed(upper) and movable(lower) contacts are in mirror arrangement (Case 1). The other is the case when one of two contacts (movable contact) is revolved at maximum angle as possible as it can be (Case 2). And at each case above, we analyzed arc driving force at two positions, position 1 is the closest to the center of contact and position 2 is near the edge of petal on fixed contact. As a result we could find that Case 2 generated stronger arc driving force than Case 1 at position 1. But at position 2 Case 1 generated stronger arc driving force than Case 2. This simulation method can contribute to optimizing spiral-type electrode designs in a view of arc driving force.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.4
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• pp.419-425
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• 2014

The current work investigated the variation of numerical solutions according to the grid number, the distance of the first grid point off the ship surface, turbulence modeling and discretization. The subject vessel is KVLCC. A commercial code, Gridgen V15 and FLUENT were used the generation of the ship hull surface and spatial system and flow computation. The first part of examination, the effect of solutions were accessed depending on the grid number, turbulence modeling and discretization. The second part was focus on the suitable selection of the distance of the first grid point off the ship surface: $Y_P+$. When grid number and discretization were fixed the same value, the friction resistance showed differences within 1 % but the pressure resistance showed big differences 9 % depending on the turbulence modeling. When $Y_P+$ were set 30 and 50 for the same discretization, friction resistance showed almost same results within 1 % according to the turbulence modeling. However, when $Y_P+$ were fixed 100, friction resistance showed more differences of 3 % compared to $Y_P+$ of 30 and 50. Whereas pressure resistance showed big differences of 10 % regardless of turbulence modeling. When turbulence modeling and discretization were set the same value, friction, pressure and total resistance showed almost same result within 0.3 % depending on the grid number. Lastly, When turbulence modeling and discretization were fixed the same value, the friction resistance showed differences within 5~8 % but the pressure resistance showed small differences depending on the $Y_P+$.

• The Journal of the Convergence on Culture Technology
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• v.4 no.1
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• pp.337-351
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• 2018

This paper discusses 5G IOT, Augmented Reality, Cloud Computing, Big Data, Future Autonomous Driving Vehicle technology, and presents 5G utilization of Pyeongchang Winter Olympic Games and Jeju Smart City model. The reason is that 5G is the main artery of the 4th industry.5G is the fourth industrial aorta because 5G is the core infrastructure of the fourth industrial revolution. In order for the AI, autonomous vehicle, VR / AR, and Internet (IoT) era to take off, data must be transmitted several times faster and more securely than before. For example, if you send a stop signal to LTE, which is a communication technology, to a remote autonomous vehicle, it takes a hundredth of a second. It seems to be fairly fast, but if you run at 100km / h, you can not guarantee safety because the car moves 30cm until it stops. 5G is more than 20 gigabits per second (Gbps), about 40 times faster than current LTE. Theoretically, the vehicle can be set up within 1 cm. 5G not only connects 1 million Internet (IoT) devices within a radius of 1 kilometer, but also has a speed delay of less than 0.001 sec. Steve Mollenkov, chief executive officer of Qualcomm, the world's largest maker of smartphones, said, "5G is a key element and innovative technology that will connect the future." With 5G commercialization, there will be an economic effect of 12 trillion dollars in 2035 and 22 million new jobs We can expect to see the effect of creation.