• Journal of Korean Elementary Science Education
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• v.33 no.2
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• pp.231-241
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• 2014

This study is subject to compare the STEAM and the STEM education of Korea, the U.K., and the U.S. to find their differences and similarities, as well as the implications in implementing the STEAM education in Korea. In order to accomplish this, the educational objectives, contents and topics, teaching and learning methods, subjects and timing for education, and convergence curriculum were compared; also, after choosing the representative program of each country, a cross-comparative analysis was done for the teaching and learning method distribution ratio, content element distribution ratio, program distribution ratio, STEAM domain ratio, curriculum structure and domain ratio, frequency of inquiry process, basic inquiry, integrated inquiry frequency, hourly basic inquiry, and integrated inquiry process. As a result, it was possible to obtain 77 programs, a total of 656 class hours of Korea, 65 programs and 846 class hours of the U.S., and 75 programs and 774 class hours of the U.K. The results are as follows: Korea's STEAM and the U.K. and the U.S.' STEM all include science, technology, engineering, arts, and mathematics, but in terms of frequency, Korea's STEAM has higher figure in arts. However, the U.K. and the U.S. have higher frequency of debate and discussion, and there were many cases of a student, after receiving feedback from other students, modifying the work.

• Journal of Convergence Society for SMB
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• v.6 no.4
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• pp.99-106
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• 2016

In this paper, we propose an adaptive FEC scheme in visible light communication using white LED. To this end, we investigate the red, green and blue mixing ratio of white LED in order to achieve the white color, and the mixing ratio of those wavelength can be defined as 4 types. Based on those properties, the FEC technique is applied to the wavelength band with the lowest mixing ratio according to mixing ratio types. At that point, we use a LDPC channel coding scheme as the FEC technique. Therefore, the proposed system can mitigate the reduction of data rate and improve total BER performance.

• Journal of the Korean Society of Industry Convergence
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• v.2 no.2
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• pp.61-68
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• 1999

The variety of crystalline structure and mechanical properties of PP filament treated with dry heat treatment at different draw ratio has been studied. Crystalline structure and mechanical properties of annealed PP filament at different draw ratio has been examined by XRD, UTM, and density method. Heat treatment has been carried out $100^{\circ}C$, $120^{\circ}C$ $140^{\circ}C$ for 30min. in dry oven. From the results of this study, it found the following facts. It was found that the crystallinity and crystallite size of (110) plane of sample were increased with increasing of annealed temperature and draw ratio. The crystalline form of annealed sample which was undrawn showed ${\alpha}$, ${\beta}$ mixing form below $120^{\circ}C$ and showed ${\alpha}$ form at $140^{\circ}C$. But the crystalline form of annealed sample which was drawn showed ${\alpha}$ form at $120^{\circ}C$. Initial modulus and tensile strength were increased with increasing of annealing temperature, and the degree of orientation was decreased with decreasing of annealing temperature.

• Journal of the Korean Society of Industry Convergence
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• v.10 no.4
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• pp.275-283
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• 2007

This study aims at the calculation of a variation of flow characteristics of main channel for tributary inflow in river junction. So this study was analyzed the variation of flow depth and velocity in main channel for a change of inflow degree. For this purpose, FLDWAV model are carried out for variations of $30^{\circ}$, $60^{\circ}$ and $90^{\circ}$ tributary inflow at junction. Results show that velocity ratio(V1/V3) increases and flow depth ratio(H1/H3) decreases for discharge ratio(Q1/Q3) of upstream and downstream when degree increases in junction. And FLDWAV model was applied at a real river junctions. Selected area is a junction of Gumho river and Sin stream. Results show that pattern is similar to a virtual channel.

• Journal of Institute of Convergence Technology
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• v.4 no.2
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• pp.11-15
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• 2014

Magnet gear transfers a high speed torque of the driving side to a low speed following side. Of course, the torque is amplified as much as a ratio between pole number of magnet gears constituting both sides through ferromagnet modulator. However, the parameters of the overall magnetic system influence the transmitting torque strongly. They include a pole number of permanent magnet, magnet thickness, reducing ratio, harmonic modulator thickness, and open ratio etc. In this paper, the influences of the parameters are analyzed using finite element method tool. By comparison, a desirable design specification is proposed, including a recommended modulator pattern.

• Journal of the Korean Society of Industry Convergence
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• v.13 no.1
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• pp.31-39
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• 2010

An exergy analysis is carried out for the regenerative gas turbine cycle which has a potential of enhanced thermal efficiency and specific power owing to the more possible water injection than that of inlet fogging under the ambient conditions. Using the analysis model in the view of the second law of thermodynamics, the effects of pressure ratio, water injection ratio and ambient temperature are investigated on the performance of the system such as exergetic efficiency, heat recovery ratio of recuperator, exergy destruction or loss ratios, and on the optimal conditions for maximum exergy efficiency. The results of computation for the typical cases show that the regenerative gas turbine system with afterfogging can make a notable enhancement of exergy efficiency.

• Journal of Communications and Networks
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• v.9 no.1
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• pp.67-74
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• 2007

The performance of dual diversity receivers operating over correlated Ricean fading channels is analyzed. Using a previously derived rapidly converging infinite series representation for the bivariate Ricean probability density function, analytical expressions for the statistics of dual-branch selection combining, maximal-ratio combining, and equal-gain combining output signal-to-noise ratio (SNR) are derived. These expressions are employed to obtain novel analytical formulae for the average output SNR, amount of fading, average bit error probability, and outage probability. The proposed mathematical analysis is used to study various novel performance evaluation results with parameters of interest the fading severity, average input SNRs, and the correlation coefficient. The series convergence rate is also examined verifying the fast convergence of the analytical expressions. The accuracy of most of the theoretical performance evaluation results are validated by means of computer simulations.

• Journal of Institute of Convergence Technology
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• v.12 no.1
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• pp.7-12
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• 2022

The reduction ratio of the magnetic gear is determined by the ratio of the number of poles between the high-speed permanent magnet layer and the low-speed permanent magnet layer. In general, it is known that the greater the least common multiple of both poles, the smaller the torque ripple called by cogging of the magnetic force generated in the magnetic gear. However, little is known about the effect of the harmonic modulator that filters the magnetic field in the magnetic gear to magnetically couple the high-speed side and the low-speed side except for the number of poles. In this study, torque ripple characteristics according to changes in modulator shape such as opening ratio and tooth thickness are analyzed using a finite element analysis tool.

• Journal of the Institute of Convergence Signal Processing
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• v.24 no.1
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• pp.1-14
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• 2023

Underwater images carry information that is useful in the fields of aquaculture, underwater military security, navigation, transportation, and so on. In this research, we transmitted an underwater image through various underwater mediums in the presence of underwater turbulence and beam attenuation effects using a high-speed visible optical carrier signal. The optical beam undergoes scintillation because of the turbulence and attenuation effects; therefore, distorted images were observed at the receiver end. To understand the behavior of the communication media, we obtained the bit error rate (BER) performance of the system with respect to the average signal-to-noise ratio (SNR). Also, the structural similarity index (SSI) and peak SNR (PSNR) metrics of the received image were evaluated. Based on the received images, we employed suitable nonlinear filters to recover the distorted images and enhance them further. The BER, SSI, and PSNR metrics of the specific nonlinear filters were also evaluated and compared with the unfiltered metrics. These metrics were evaluated using the on-off keying and binary phase-shift keying modulation techniques for the 50-m and 100-m links for beam attenuation resulting from pure seawater, clear ocean water, and coastal ocean water mediums.

• Journal of electromagnetic engineering and science
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• v.4 no.2
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• pp.93-96
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• 2004

In this paper we introduce a new escalator(ESC) structure-based adaptation algorithm. The proposed algorithm is independent of eigenvalues spread ratio(ESR) of channel and has faster convergence speed than that of the conventional ESC algorithms. This algorithm combines the fast adaptation ability of least square methods and the orthogonalization property of the ESC structure. From the simulation results the proposed algorithm shows superior convergence speed and no slowing down of convergence speed when we increase the ESR of the channel.