• The Journal of the Acoustical Society of Korea
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• v.13 no.6
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• pp.75-82
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• 1994

The ray paths and travel times of sound wave in the ocean depend on the physical properties of the propagating media. Ocean Acoustic Tomography(OAT), which is inversely estimate the travel time variations between fixed sources and receivers the physical properties of the corresponding media can he understood. To apply ocean survey technology by using the OAT, the tomographic procedure requires forward problem that variation of the travel times be identified with the variability of the medium. Also, received signals must be satisfied the necessary conditions of ray path stability, identification and resolution in order for OAT to work. The canonical ocean has been determined based on the historical data and its travel time and ray path are used as reference values. The sound speed of canonical ocean in the East Sea is about 1523 m/s at the surface and 1458 m/s at the sound channel axis(400m). Sound speeds in the East Sea are perturbed by warm eddy whose horizontal extension is more than 100 km with deeper than 200 m in depth scale. In this study, an acoustic source and receiver are placed at the depth above the sound channel axis, 350 m, and are separated by 200 km range. Ray paths are identified by the ray theory methed in a range dependent medium whose sound speeds are functions of a range and depth. The eigenray information obtained from interpolation between the rays bracketing the receiver are used to simulate the received signal by convolution of source signal with the eigenray informations. The source signal is taken as a 400 Hz rectangular pulse signal, bandwidth is 16 Hz and pulse length is 64 ms. According to the analysis of the received signal and identified ray path by using numerical model of underwater sound propagation, simulated signals satisfy the necessary conditions of OAT, applied in the East Sea.

• The Journal of Art Theory & Practice
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• no.4
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• pp.77-104
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• 2006

The propaganda paintings in oil colors or in forms of posters made from 1949 to 1966 have gone through some changes experiencing the influence of the Soviet Union Art and discussion of nationalization, while putting political messages of the time in the picture planes. The propaganda paintings which have been through this process became an effective means of encouraging the illiterate people in political ideologies, production, and learning. Alike other propaganda paintings in different mediums, the ones which were painted in oil colors and in the form of posters have been produced fundamentally based on Mao Zedong's intensification of the literary art on the talks on literature at Yenan. Yet, the oil paintings and posters were greatly influenced by the socialist realism and propaganda paintings of the Soviet Union, compared to other propaganda paintings in different mediums. Accordingly, they were preponderantly dealt in the discussions of nationalization of the late '50s. To devide in periods, the establishment of People's Republic of China in 1949 as a diverging point, the propaganda paintings made before and after 1949 have differences in subject matters and styles. In the former period, propaganda paintings focused on the political lines of the Communists and enlightenment of the people, but in the latter period, the period of Cultural Revolution, the most important theme was worshiping Mao Zedong. This was caused by reflection of the social atmosphere, and it is shown that the propaganda painters had reacted sensitively to the alteration of politics and the society. On the side of formalities, the oil paintings and posters made before the Cultural Revolution were under a state of unfolding several discussions including nationalization while accepting the Soviet Union styles and contents, and the paintings made afterwards show more of unique characteristics of China. In 1956, the discussion about nationalization which had effected the whole world of art, had strongly influenced the propaganda paintings in oil colors more than anything. There were two major changes in the process of making propaganda paintings in oil colors. One was to portray lives of the Chinese people truthfully, and the other was to absorb the Chinese traditional styles of expression. After this period, the oil painters usually kept these rules in creating their works, and as a result, the subject matters, characters, and backgrounds have been greatly Sinicized. For techniques came the flat colored surface of the new year prints and the traditional Chinese technique of outlining were used for expressing human figures. While the propaganda paintings in oil colors achieved high quality and depth, the posters had a very direct representation of subject matters and the techniques were unskilled compared to the oil paintings. However, after the establishment of People's Republic of China, the posters were used more than any other mediums for propagation of national policy and participation of the political movements, because it was highly effective in delivering the policies and political lines clearly to the Chinese people who were mostly illiterate. The poster painters borrowed techniques and styles from the Soviet Union through books and exhibitions on Soviet Union posters, and this relation of influences constantly appears in the posters made at the time. In this way, like the oil paintings, the posters which have been made with a direct influence of the Soviet Union had developed a new, sinicised process during the course of nationalization. The propaganda paintings in oil colors or in forms of posters, which had undergone the discussion of nationalization, had put roots deep down in the lives of the Chinese people, and this had become another foundation for the amplification of influences of political propaganda paintings in the following period of Cultural Revolution.

• Science of Emotion and Sensibility
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• v.21 no.4
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• pp.55-62
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• 2018

The two main requirements of wearable optical fiber fabrics are that they must presuppose a high degree of flexibility and they must maintain the luminance effect in both flat and bent conformations. Therefore, woven optical fiber fabrics that satisfy the above conditions were developed by both weaving and by using computer embroidery. First, we measured the brightness of the wearable optical fiber fabric in the flat state at a total of 10 measurement points at intervals of 1 cm. Second, the wearable optical fiber fabric was placed horizontally on the forearm, where three-dimensional bending occurs, and the luminance values were recorded at the same 10 measurement points. For the woven fabric in the flat state, the maximum, minimum, average, and standard deviation luminance values were $5.23cd/m^2$, $2.74cd/m^2$, $3.56cd/m^2$, and $1.11cd/m^2$, respectively. The corresponding luminance values from the bent forearm were $7.92cd/m^2$ (maximum), $2.37cd/m^2$ (minimum), $4.42cd/m^2$ (average), and $2.16cd/m^2$ (standard deviation). In the case of the computer-embroidered fabric, the maximum, minimum, average, and standard deviation luminance values in the flat state were $7.56cd/m^2$, $3.84cd/m^2$, $5.13cd/m^2$, and $1.04cd/m^2$, respectively, and in the bent forearm state were $9.6cd/m^2$, $3.63cd/m^2$, $6.13cd/m^2$, and $2.26cd/m^2$, respectively. Therefore, the computer-embroidered fabric exhibited a higher luminous effect than the woven fabric because the detailed structure reduced light-loss due to the backside fabric. In both types of wearable optical fiber fabric the luminance at the forearm was 124% and 119%, respectively, and the light emitting effect of the optical fiber fabric was maintained even when bent by the human body. This is consistent with the principle of Huygens, which defines the wave theory of light, and also the Huygens-Fresnel-Kirchhoff principle, which states that the intensity of light increases according to the magnitude of the angle of propagation of the light wavefront (${\theta}$).

• Journal of the Daesoon Academy of Sciences
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• v.29
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• pp.241-278
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• 2017

This study aims to classify broadscale anti-religious movements in Korea based on critical public sentiment and analyze the meanings of these movements. To carry out the research, global religious changes that have occurred in modern times were closely looked into first. The world religions have had an influence on the world's religious awareness. As a result, they intend to acquire universality on their own individual grounds while keeping consistency with the past. This phenomenon used to appear to retain the identity, recreate tradition, transform itself to fit in the present times, pursue innovation, or even become overshadowed by other forms of thought such as when religions have collided with nationalism. How does Korean society perceive the changes that emerged in world religions? In general, the circumstances that Korea faces in this era tend to manifest themselves via the Internet, multimedia, and Youtube wherein they sound off on religion and this includes criticism of Christianity, demand for reformation, attack on minor religions, pro-reform academic circles and media, and the propagation of anti-theism. Criticism of religion is interpreted as an anti-religious movement. The secularism and anti-theism brought up by some Western scholars and critical theories of religion from scientific or historical perspectives are being spread through bookstores. Christianity is prone to reflecting on itself and trying to emphasizing a meta-religious spirituality. This in short, characterizes anti-religious movements in Korea. Indeed, criticism against particular religions has also emerged in the past. However, anti-religious movements that have recently come into existence in Korea are in some regards unprecedented when compared to that of the past in terms of their patterns and context. Especially, the active anti-Christianity movement in general is definitely a new phenomenon. This research mainly focused on Christianity, but on-going anti-religious movements will be a major topic for further research that aims to understand the religious changes unfolding in Korea.

• Economic and Environmental Geology
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• v.5 no.4
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• pp.187-209
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• 1972

Drilling position is one of the most important factors affecting on the blasting effects. There has been many reports on several blasting factors of burn-cut by Messrs. Brown and Cook, but in this study the author tried to compare drilling positions of burn-cut to pyramid-cut, and also to correlate burn-cut effects of drilling patterns, not being dealt by Prof. Ito in his theory, which emphasized on dynamical stress analysis between explosion and free face. According to former theories, there break out additional tensile stress reflected at the free face supplemented to primary compressive stress on the blasting with one-free-face. But with these experimented new drilling patterns of burn-cut, more free faces and nearer distance of each drilling holes make blasting effects greater than any other methods. To promote the above explosive effect rationary, it has to be considered two important categories under-mentioned. First, unloaded hole in the key holes should be drilled in wider diameter possibly so that it breaks out greater stress relief. Second, key holes possibly should have closer distances each other to result clean blasting. These two important factors derived from experiments with, theories of that the larger the dia of the unloaded hole, it can be allowed wider secondary free faces and closes distances of each holes make more developed stress relief, between loaded and unloaded holes. It was suggested that most ideal distance between holes is about 4 clearance in U. S. A., but the author, according to the experiments, it results that the less distance allow, the more effective blasting with increased broken rock volume and longer drifted length can be accomplished. Developed large hole burn-cut method aimed to increase drifting length technically under the above considerations, and progressive success resulted to achieve maximum 7 blasting cycles per day with 3.1m drifting length per cycle. This achievement originated high-speed-drifting works, and it was also proven that application of Metallic AN-FO on large hole burn-cut method overcomes resistance of one-free-face. AN-FO which was favored with low price and safety handling is the mixture of the fertilizer or industrial Ammonium-Nitrate and fuel oil, and it is also experienced that it shows insensible property before the initiation, but once it is initiated by the booster, it has equal explosive power of Ammonium Nitrate Explosives (ANE). There was many reports about AN-FO. On AN-FO mixing ratio, according to these experiments, prowdered AN-FO, 93.5 : 6.5 and prilled AN-FO 94 : 6, are the best ratios. Detonation, shock, and friction sensities are all more insensitive than any other explosives. Residual gas is not toxic, too. On initation and propagation of the detonation test, prilled AN-FO is more effective than powered AN-FO. AN-FO has the best explosion power at 7 days elapsed after it has mixed. While AN-FO was used at open pit in past years prior to other conditions, the author developed new improved explosives, Metallic AN-FO and Underwater explosive, based on the experiments of these fundmental characteristics by study on its usage utilizing AN-FO. Metallic AN-FO is the mixture of AN-FO and Al, Fe-Si powder, and Underwater explosive is made from usual explosive and AN-FO. The explanations about them are described in the other paper. In this study, it is confirmed that the blasting effects of utilizing AN-FO explosives are very good.