• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.8
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• pp.3800-3805
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• 2012

Infrared(IR) reflective black cool pigment and paint which is used for interior/exterior materials(IR reflectance >30%) to prevent heat island effect and to increase energy efficiency were studied. Cool pigment was synthesized using mixture of $Fe_2O_3$ and $Cr_2O_3$ with calcination from 900 to $1,200^{\circ}C$. Cool paint was prepared by formulation of cool pigment, acrylic resins, and other additives. Results showed that optimum color fixation of pigment obtained by mole ratio of Fe to Cr was 0.9 with calcination temperature at $1,000^{\circ}C$. The cool paint formulated by 20% pigment and 1.5% dispersive additive with $125{\mu}m$ thickness of coated layer showed optimum IR reflectance. Temperature difference on surface between cool paint and ordinary paint(STD) was $36.5^{\circ}C$ and IR reflectance(TSR) was 39.3% at wavelength from 700 to 2,500nm. And color change was not detected during 500hrs weathering test.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.276-279
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• 2004

Plasma enhanced chemical vapor deposition (PECVD) of silicon nitride (SiN) is a proven technique for obtaining layers that meet the needs of surface passivation and anti-reflection coating. In addition, the deposition process appears to provoke bulk passivation as well due to diffusion of atomic hydrogen. This bulk passivation is an important advantage of PECVD deposition when compared to the conventional CVD techniques. A further advantage of PECVD is that the process takes place at a relatively low temperature of 300t, keeping the total thermal budget of the cell processing to a minimum. In this work SiN deposition was performed using a horizontal PECVD reactor system consisting of a long horizontal quartz tube that was radiantly heated. Special and long rectangular graphite plates served as both the electrodes to establish the plasma and holders of the wafers. The electrode configuration was designed to provide a uniform plasma environment for each wafer and to ensure the film uniformity. These horizontally oriented graphite electrodes were stacked parallel to one another, side by side, with alternating plates serving as power and ground electrodes for the RF power supply. The plasma was formed in the space between each pair of plates. Also this paper deals with the fabrication of multicrystalline silicon solar cells with PECVD SiN layers combined with high-throughput screen printing and RTP firing. Using this sequence we were able to obtain solar cells with an efficiency of 14% for polished multi crystalline Si wafers of size 125 m square.

• Advances in aircraft and spacecraft science
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• v.3 no.3
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• pp.243-257
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• 2016

The increase of air traffic volume has brought an increasing amount of issues related to carbon and NOx emissions and noise pollution. Aircraft manufacturers are concentrating their efforts to develop technologies to increase aircraft efficiency and consequently to reduce pollutant discharge and noise emission. Ultra High By-Pass Ratio engine concepts provide reduction of fuel consumption and noise emission thanks to a decrease of the jet velocity exhausting from the engine nozzles. In order to keep same thrust, mass flow and therefore section of fan/nacelle diameter should be increased to compensate velocity reduction. Such feature will lead to close-coupled architectures for engine installation under the wing. A strong jet-wing interaction resulting in a change of turbulent mixing in the aeroacoustic field as well as noise enhancement due to reflection phenomena are therefore expected. On the other hand, pressure fluctuations on the wing as well as on the fuselage represent the forcing loads, which stress panels causing vibrations. Some of these vibrations are re-emitted in the aeroacoustic field as vibration noise, some of them are transmitted in the cockpit as interior noise. In the present work, the interaction between a jet and wing or fuselage is reproduced by a flat surface tangential to an incompressible jet at different radial distances from the nozzle axis. The change in the aerodynamic field due to the presence of the rigid plate was studied by hot wire anemometric measurements, which provided a characterization of mean and fluctuating velocity fields in the jet plume. Pressure fluctuations acting on the flat plate were studied by cavity-mounted microphones which provided point-wise measurements in stream-wise and spanwise directions. Statistical description of velocity and wall pressure fields are determined in terms of Fourier-domain quantities. Scaling laws for pressure auto-spectra and coherence functions are also presented.

• Journal of the Korean School Mathematics Society
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• v.24 no.2
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• pp.191-216
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• 2021

This study analyzes how statistical literacy is implemented along with the statistical problem-solving process as described in the Statistical Estimation Unit of the textbook by the 2015 revised mathematics curriculum. The analytical framework was developed from the literature, and consists of 'context', 'variability', 'mathematical and statistical knowledge', 'using of technological instruments', 'critical attitude', and 'communication'. From the perspective of the statistical problem-solving process, the analysis revealed that many tasks equivalent to 'Analyzing Data' but lacked tasks related to 'Interpreting Results' and 'Formulating Questions'. As a result of analyzing the reflection of each element of statistical literacy, 'mathematical and statistical knowledge' was the most common task, but 'critical attitude' and 'using of technological instruments' were rarely dealt with. Based on the results of this textbook analysis, it was intended to provide implications for improving the curriculum and the development of textbooks for the growth of statistical literacy.

• Journal of Engineering Education Research
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• v.24 no.6
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• pp.3-19
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• 2021

This study aimed to introduce a case study of a basic engineering design course using the ENACT model for fostering social responsibility of engineers, and to investigate the educational effects of the course. Since the ENACT model was designed to encourage STEM college students to pursue responsible problem solving based on their understanding of socioscientific issues, we assumed that it would be beneficial for engineering students to foster their social responsibility as well as their understanding of science/engineering-related issues. A total of 49 engineering students who enrolled in the course participated in the study. Data included students' course artifacts, reflection papers, and responses to survey questionnaires. Results indicated that the students became more aware of nature of science and technology after the program, and began to solve the problems while considering the views of multiple stakeholders. They highly valued the experience of communicating with others as engaging in the civic activities. They also expressed high satisfaction and feeling of achievement on the course learning. We expect the ENACT model to be an effective teaching guideline that fosters the social responsibility of engineering students and furthermore, engineering ethics.

• 한국노년학
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• v.30 no.1
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• pp.65-80
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• 2010

Purpose: The purpose of this study was to develop a wisdom scale among Korean elderly with high validity and reliability. Method: The process of the development of this scale follows: A conceptual framework was identified based on literature a review of the elderly and discussion with experts in physiology and sociology. Total 128 items were developed. Through reliability testing, factor analysis, 60 preliminary items, and 4-points scale were selected. By a means of the internal consistency for 60 items, 33 items were deleted. Finally, 27 items were remained. To verity 27 items, factor analysis, reliability testing, and correlation were done. Data were collected from 480 elderly subjects in Daegu, Kyungpook Province, and Busan, Kyungnam Province from August, 2008 to February, 2009. Results: From the results of the factor analysis for 27 items, 3 factors were extracted. These factors were labeled as 'empathic emotion', 'self-reflection', and 'bitter experience of life'. Cronbach's Alpha for the 27 items was .921 and correlation coefficient of ego-integrity was .69. Conclusion: An exploratory study of the variables related to wisdom among the elderly is needed for criterion validity of this scale. A study on wisdom for different age groups is needed for re-verification.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.1
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• pp.27-32
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• 2019

This study describes the design and implementation of a simulated signal generator to demonstrate the performance of VHF band radar for the detection of small targets in RCS(Radar Cross Section). The transmission and reception antenna beam widths used in the simulated signal generating apparatus may be large, which may cause problems in the degree of isolation. Interference signal immunity and isolation characteristics are improved by considering operating conditions of VHF radar to solve isolation of antennas. Simulated signal generator performs the following: VHF radar transmission and reception correction, simulation signal generation, target Doppler, RCS and distance simulation, remote control, and GPS clock synchronization function. After the fabrication of the simulated signal generator, the main characteristics, such as the output characteristics and the reflection signal simulations, were tested. When the microwave radar assembly is completed in the future, it will be utilized for the performance evaluation of VHF radar.

• Korean Journal of Optics and Photonics
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• v.29 no.6
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• pp.262-267
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• 2018

In this paper, we designed a new antireflective film to improve the optical efficiency of organic light-emitting diode displays (OLEDs). The reflection characteristics in the normal and side viewing directions of OLEDs with the antireflective film were calculated, depending on the degree of polarization and transmittance of the currently used polarizer when used in the antireflective film of an OLED. The results showed that when the polarization degree of the commercial polarizer (99.990~99.995%) is lowered to 99.900%, the average reflectance of the antireflective film is increased by about 0.1% (2.5% in terms of rate of increase) which is difficult to notice with the human eye, while the transmittance is increased by 1.63~3.34% (4.2~8.2% in terms of rate of increase). This study provides an optimal design for high-light-efficiency OLEDs with good antireflection properties.

• Korean Journal of Remote Sensing
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• v.35 no.1
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• pp.39-55
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• 2019

In this study, we have proposed an improved method to detect forest fires by correcting the reflected signals of day images using the middle-wavelength infrared (MWIR) channel. The proposed method is allowed to remove the reflected signals only using the image itself without an existing data source such as a land-cover map or atmospheric data. It includes the processing steps for calculating a solar-reflected signal such as 1) a simple correction model of the atmospheric transmittance for the MWIR channel and 2) calculating the image-based reflectance. We tested the performance of the method using the MODIS product. When compared to the conventional MODIS fire detection algorithm (MOD14 collection 6), the total number of detected fires was improved by approximately 17%. Most of all, the detection of fires improved by approximately 30% in the high reflection areas of the images. Moreover, the false alarm caused by artificial objects was clearly reduced and a confidence level analysis of the undetected fires showed that the proposed method had much better performance. The proposed method would be applicable to most satellite sensors with MWIR and thermal infrared channels. Especially for geostationary satellites such as GOES-R, HIMAWARI-8/9 and GeoKompsat-2A, the short acquisition time would greatly improve the performance of the proposed fire detection algorithm because reflected signals in the geostationary satellite images frequently vary according to solar zenith angle.

• The Research Journal of the Costume Culture
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• v.26 no.6
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• pp.823-835
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• 2018

The body is an important object of costume expression, and the reflection of the aesthetics of the body according to age, culture, individual or group determines the form of the costume. In particular, British artist Leigh Bowery provided many designers and celebrities with original design ideas. Leigh Bowery's costumes are related to the carnival concept. Thus, this study analyzed Leigh Bowery's life and works, and examined Michael Bakhtin's grotesque carnivalesque theory. Based on Bakhtin's carnival theory around 100 works by Leigh Bowery, in the form of YouTube videos and DVD clips were analyzed in this study. The results of the analysis Leigh Bowery's body and costume research are as follows. First, this study can define fetishism as a characteristic of costumes such as body suits, harnesses, high-heeled boots, and stockings, that stress the body. Second, the character of the body is not expressed as that of an idealized body, but the fat and ugly aspect are revealed. Third, Leigh Bowery's costumes are characterized by ambiguity. The costumes blur the boundaries between women and men. Fourth, common sense, combined with normal and bizarre, brings out a strong sense of carnival humor with ridiculousness arising from the gap between reality and reality. His performance has had a significant impact on victims of discrimination or unequal treatment in sexual, racial, and age-related situations. This study should inspire many designers through the study of Leigh Bowery's body expression and dress, but it also introduces fashion icons that are not well known in Korea.