• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.5
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• pp.299-308
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• 2022

This study was conducted to predict the tendency for heat exchange and boil-off gas (BOG) in a liquefied hydrogen tank under sloshing excitation. First, athe fluid domain excited by sloshing was modeled using a multiphase-thermal flow domain in which liquid hydrogen and hydrogen gas are in the saturated state. Both the the volume of fluid (VOF) and Eulerian-based multi-phase flow methods were applied to validate the accuracy of the pressure prediction. Second, it was indirectly shown that the fluid velocity prediction could be accurate by comparing the free surface and impact pressure from the computational fluid dynamics with those from the experimental results. Thereafter, the heat ingress from the external convective heat flux was reflected on the outer surfaces of the hydrogen tank. Eulerian-based multiphase-heat flow analysis was performed for a two-dimensional Type-C cylindrical hydrogen tank under rotational sloshing motion, and an inflation technique was applied to transform the fluid domain into a computational grid model. The heat exchange and heat flux in the hydrogen liquid-gas mixture were calculated throughout the analysis,, whereas the mass transfer and vaporization models were excluded to account for the pure heat exchange between the liquid and gas in the saturated state. In addition, forced convective heat transfer by sloshing on the inner wall of the tank was not reflected so that the heat exchange in the multiphase flow of liquid and gas could only be considered. Finally, the effect of sloshing on the amount of heat exchange between liquid and gas hydrogen was discussed. Considering the heat ingress into liquid hydrogen according to the presence/absence of a sloshing excitation, the amount of heat flux and BOG were discussed for each filling ratio.

• Analytical Science and Technology
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• v.19 no.6
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• pp.460-467
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• 2006

Carbon-coated $TiO_2$ was prepared by $CCl_4$ solvent mixing method with different heat treatment temperature (HTT). Since the carbon layers derived from pitch on the $TiO_2$ particles were porous, the carbon-coated $TiO_2$ sample series showed a good adsorptivity and photo decomposition activity. The BET surface area was decreased by the increasing of the heat treatment temperature. The SEM results present to the characterization of surface texture on the carbon-coated $TiO_2$ sample and carbon distributions on the surfaces for all the materials used. The main elements of C, O and Ti were shown from EDX spectra. And the quantity of these elements is very rich in the samples. From XRD data, the pristine anatase peaks were observed in the X-ray diffraction patterns for the carbon-coated $TiO_2$ at the different HTTs. However, the rutile peaks were observed for the carbon-coated $TiO_2$ at HTT of 1073 K and 1123 K. Finally, the excellent photocatalytic activity of carbon-coated $TiO_2$ with UV-vis spectra between absorbance and time could be attributed to the homogeneous coated carbon on the external surface and structural phase transform, and the photocatalytic activity was decreased by the increasing of the HTT.

• The Journal of Korean Medicine
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• v.16 no.2 s.30
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• pp.453-489
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• 1995

The research of the phrases related with physiology of stomach and spleen in the contents of Huang Di Nei Jing(黃帝內經) known as the Bible of oriental medicine will make a contribution to a deep understanding of disease of stomach and spleen and a proper clinical diagnosis and treatment of them. In this research of the most appropriate glosses recorded nine kinds of representative medical books including Huang Di Nei Jing Somoon(黃帝內經素問) of Wang Bing(王氷) were picked out: The summaries of the selected contents are as follows: 1. The word 'saliva(涎)' in 'the spleen controls saliva(脾爲涎)' can be viewed as a generic term referring to oral cavity secretion gland as well as the secretion fluid of salivary gland. 2. The phases 'a large reservoir(太倉)', barn organs', 'a reserboir of food stuff', 'a stomach as the market(胃爲之市)', etc mean the function of stomach to receive food(胃主受納). 3. The phase 'generation of five tastes(五味出焉)' means both 'the function of stomach to transform food into chyme(胃主腐熟)' and 'the channelling function of spleen.(脾主運化)' 4. The flowing of the food-Qi(食氣) into stomach brings about spreading Jung(精) into liver and then percolating Jung(精) flow into channel. The channel-Qi(脈氣) flows into lung through channel. As a result, all kinds of channels gather together in lung and Jung(精) is sent into skin and hair. The assembly of Jung(精) with skins and channels moves Qi(氣) into fu-organ and so jung(精) and mental activity(神明) in fu-organ(府) come to be in four organs(四臟). Then if Qi(氣) comes back to power balance unit(權衡) being in the state of equilibrium(權衡以平), the hole of Qi(氣口) comes to determine the matter of life and death through achieving Chun-quan-chi(-寸-關-尺). The above mentioned phrases means the digestion, asorption and transmission of food. When food is taken in stomach, Jung-Qi(精氣) comes to be over flowed upward into spleen, back into lung, finally downward into bladders through water-conduit(水道) controlled by lung. When water- Jung(水精) radiates into whole body with channels of five organs(五臟), both of them fit together with and yin-yang(陰-陽). Therefore, the grasping of the rise and decline of yin-yang(陰C-陽) is necessary to consult patients. The above mentioned phrases is properly viewed to designate the asorption, transmission and excretion of food. 5. Spleen controls flesh(脾之合肉也), the state of spleen is known by human lips, and what this means is that liver plays functions of spread and expansion(肝主疏泄). 6. The phrase 'Jung Jung'((中精)) in 'gallbladder dominates Jung jung(膽主中精)', which in one of the specific expression of 'liver plays functions of spread and expansion(肝主疏泄). 7. It is right that the phase 'The eleven organs in all are determined by gallbladder'(凡十,一臟取決於膽也) is correctly paraphrased as 'only one of ten organs, spleen, is determined by gallbladder'.(凡十,一臟取決於膽也), 8. The small intestine is an organ. which receives the materials digested and sends them out. This means that the function of transforming materials(化物) factually refers to that of separating clearity and blur(泌別淸濁). And it is also thought to have the function of ascending clearity and descending blur(升淸降濁), 9. A large intestine is a transmitting organ(傳導之官) from which a change comes out(變化出焉). the phrase 'change'(變化) in this sentence means both the intake of water and nutrition and the formation procedure of stool through excretion of mucocele.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.8
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• pp.253-263
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• 2013

Frequency Scanning Interferometry(FSI) system, one of the most promising optical surface measurement techniques, generally results in superior optical performance comparing with other 3-dimensional measuring methods as its hardware structure is fixed in operation and only the light frequency is scanned in a specific spectral band without vertical scanning of the target surface or the objective lens. FSI system collects a set of images of interference fringe by changing the frequency of light source. After that, it transforms intensity data of acquired image into frequency information, and calculates the height profile of target objects with the help of frequency analysis based on Fast Fourier Transform(FFT). However, it still suffers from optical noise on target surfaces and relatively long processing time due to the number of images acquired in frequency scanning phase. 1) a Polarization-based Frequency Scanning Interferometry(PFSI) is proposed for optical noise robustness. It consists of tunable laser for light source, ${\lambda}/4$ plate in front of reference mirror, ${\lambda}/4$ plate in front of target object, polarizing beam splitter, polarizer in front of image sensor, polarizer in front of the fiber coupled light source, ${\lambda}/2$ plate between PBS and polarizer of the light source. Using the proposed system, we can solve the problem of fringe image with low contrast by using polarization technique. Also, we can control light distribution of object beam and reference beam. 2) the signal processing acceleration method is proposed for PFSI, based on parallel processing architecture, which consists of parallel processing hardware and software such as Graphic Processing Unit(GPU) and Compute Unified Device Architecture(CUDA). As a result, the processing time reaches into tact time level of real-time processing. Finally, the proposed system is evaluated in terms of accuracy and processing speed through a series of experiment and the obtained results show the effectiveness of the proposed system and method.

• The Journal of the Acoustical Society of Korea
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• v.20 no.4
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• pp.35-41
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• 2001

This paper describes Linear Discriminant Analysis and common vector extraction for speech recognition. Voice signal contains psychological and physiological properties of the speaker as well as dialect differences, acoustical environment effects, and phase differences. For these reasons, the same word spelled out by different speakers can be very different heard. This property of speech signal make it very difficult to extract common properties in the same speech class (word or phoneme). Linear algebra method like BT (Karhunen-Loeve Transformation) is generally used for common properties extraction In the speech signals, but common vector extraction which is suggested by M. Bilginer et at. is used in this paper. The method of M. Bilginer et al. extracts the optimized common vector from the speech signals used for training. And it has 100％ recognition accuracy in the trained data which is used for common vector extraction. In spite of these characteristics, the method has some drawback-we cannot use numbers of speech signal for training and the discriminant information among common vectors is not defined. This paper suggests advanced method which can reduce error rate by maximizing the discriminant information among common vectors. And novel method to normalize the size of common vector also added. The result shows improved performance of algorithm and better recognition accuracy of 2％ than conventional method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.3 s.118
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• pp.248-256
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• 2007

In this paper, we propose a selective DFT spreading method to solve a high PAPR problem in uplink OFDMA system. A selective characteristic is added to the DFT spreading, so the DFT spreading method is mixed with SLM method. However, to minimize increment of computational complexity, differently with common SLM method, our proposed method uses only one DFT spreading block. After DFT, several copy branches are generated by multiplying with each different matrix. This matrix is obtained by linear transforming the each phase rotation in front of DFT block. And it has very lower computational complexity than one DFT process. For simulation, we suppose that the 512 point IFFT is used, the number of effective sub-carrier is 300, the number of allowed sub-carrier to each user's is 1/4 and 1/3 and QPSK modulation is used. From the simulation result, when the number of copy branch is 4, our proposed method has more than about 5.2 dB PAPR reduction effect. It is about 1.8 dB better than common DFT spreading method and 0.95 dB better than common SLM which uses 32 copy branches. And also, when the number of copy branch is 2, it is better than SLM using 32 copy branches. From the comparison, the proposed method has 91.79 % lower complexity than SLM using 32 copy branches in similar PAPR reduction performance. So, we can find a very good performance of our proposed method. Also, we can expect the similar performance when all number of sub-carrier is allocated to one user like the OFDM.

• The Southeast Asian review
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• v.20 no.3
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• pp.263-297
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• 2010

The relics of the Southeast Asian civilizations in the first phase are found with the relics from India, China, and even further West of Persia and Rome. These relics are the historic marks of the ancient interactions of various continents, mainly through the maritime trade. The traces of the indic culture, which appears in the historic age, are represented in the textual records and arts, regarded as the essence of the India itself. The ancient Hindu arts found in various locations of Southeast Asia were thought to be transplanted directly from India. However, Neither did the Gupta Hindu Art of India form the mainstream of the Gupta Art, nor did it play an influential role in the adjacent areas. The Indian culture was transmitted to Southeast Asia rather intermittently than consistently. If we thoroughly compare the early Hindu art of India and that of Southeast Asia, we can find that the latter was influenced by the former, but still sustained Southeast Asian originality. The reason that the earliest Southeast Asian Hindu art is discovered mostly in continental Southeast Asia is resulted from the fact that the earliest networks between India and the region were constructed in this region. Among the images of Hindu gods produced before the 7th century are Shiva, Vishnu, Harihara, and Skanda(the son of Shiva), and Ganesha(the god of wealth). The earliest example of Vishnu was sculpted according to the Kushan style. After that, most of the sculptures came to have robust figures and graceful proportions. There are a small number of images of Ganesha and Skanda. These images strictly follow the iconography of the Indian sculpture. This shows that Southeast Asians chose their own Hindu gods from the Hindu pantheon selectively and devoted their faiths to them. Their basic iconography obediently followed the Indian model, but they tried to transform parts of the images within the Southeast Asian contexts. However, it is very difficult to understand the process of the development of the Hindu faith and its contents in the ancient Southeast Asia. It is because there are very few undamaged Hindu temples left in Southeast Asia. It is also difficult to make sure that the Hindu religion of India, which was based on the complex rituals and the caste system, was transplanted to Southeast Asia, because there were no such strong basis of social structure and religion in the region. "Indianization" is an organized expansion of the Indian culture based on the sense of belonging to an Indian context. This can be defined through the process of transmission and progress of the Hindu or Buddhist religions, legends about purana, and the influx of various epic expression and its development. Such conditions are represented through the Sanskrit language and the art. It is the element of the Indian culture to fabricate an image of god as a devotional object. However, if we look into details of the iconography, style, and religious culture, these can be understood as a "selective reception of foreign religious culture." There were no sophisticated social structure yet to support the Indian culture to continue in Southeast Asia around the 7th century. Whether this phenomena was an "Indianization" or the "influx of elements of Indian culture," it was closely related to the matter of 'localization.' The regional character of each local region in Southeast Asia is partially shown after the 8th century. However it is not clear whether this culture was settled in each region as its dominant culture. The localization of the Indian culture in Southeast Asia which acted as a network connecting ports or cities was a part of the process of localization of Indian culture in pan-Southeast Asian region, and the process of the building of the basis for establishing an identity for each Southeast Asian region.