• 한국전산유체공학회지
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• 제20권4호
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• pp.58-62
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• 2015

Recent studies on wall-bounded shear flow have emphasized the significance of the stable manifold of simple nonlinear invariant solutions to the Navier-Stokes equation in the formation of the boundary between the laminar and turbulent regions in state space. In this paper we present newly discovered homoclinic orbits of the Kawahara and Kida(2001) periodic solution in plane Couette flow. We show that as the Reynolds number decreases a pair of homoclinic orbits move closer to each other until they disappear to exhibit homoclinic tangency.

• 기술혁신연구
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• 제10권2호
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• pp.107-129
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• 2002

Expansion and enhancement of information and communication infrastructure can create a market closer to an ideal type for a perfect competition, utilizing a cyber space in the network (with the expanded usage of Internet and e-commerce) and it could be a market of a monopolistic form. The government can take one of the two approaches responding to this monopolization of the digital market. First, the government maintains laissez-faire policy since the monopoly cannot be maintained over a long period of time due to an increasing in the production, decrease in the price, profit resulting from this and rapid technology evolution. Second, the government can actively interrupt the monopolization of the digital market. Monopolization in a digital market can lead to a market failure. Unstable market structure and too much frequent merger and acquisition contribute to making the digital market very dynamic. Information goods exchanged in the digital market have the features of very low marginal cost required to copy the original product whereas its initial fixed cost is very high. This explains why the information products are not priced based on the existing marginal price determination principles and why companies producing them have various product sales strategies (price/product differentiation strategy, and other sales strategies).

• Tuberculosis and Respiratory Diseases
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• 제40권4호
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• pp.353-356
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• 1993

Advent of new imaging modalities such as computed tomography, magnetic resonance imaging and ultrasound contributed greately to the specific imaging diagnosis. However plain chest X-ray is still most prequently used for imaging diagnosis of respiratory disease in clinical pratic and it is important to make a good quality of X-ray film and good interpretation. The optimal chest X-ray should be taken with full inspiration without rotation and motion and the exposure is at the level of barely demonstrable thoracic vertebral disc space. It is recommended that higk KVP technique for detection of lesions which is overlaped by mediastinum, heart and rib cage. It is better to examine chest X-ray film start at some distance(6-8 feet) and closer to the film later on and the reader should not read a film in fatigue condition. The reading room should be quiet and relately dark illumination. It is important, to make a good X-ray film and good interpretation to reduce the observer error.

• 천문학회보
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• 제39권1호
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• pp.59.2-59.2
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• 2014

Radiative transfer models in a spherical, turbulent interstellar medium (ISM), in which the photon source is situated at the center, are calculated to investigate the correlation between the scattered light and the dust column density. The medium is modeled using fractional Brownian motion structures that are appropriate for turbulent ISM. The correlation plot between the scattered light and optical depth shows substantial scatter and deviation from simple proportionality. It was also found that the overall density contrast is smoothed out in scattered light. In other words, there is an enhancement of the dust-scattered flux in low-density regions, while the scattered flux is suppressed in high-density regions. The correlation becomes less significant as the scattering becomes closer to being isotropic and the medium becomes more turbulent. Therefore, the scattered light observed in near-infrared wavelengths would show much weaker correlation than the observations in optical and ultraviolet wavelengths. We also find that the correlation plot between scattered lights at two different wavelengths shows a tighter correlation than that of the scattered light versus the optical depth.

• 대한전기학회논문지
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• 제45권1호
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• pp.159-163
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• 1996

Simulated electron tunneling time through a potential barrier is compared with theoretical phase time. For a GaAs/Al/sub 0.3/Ga/sub 0.7/As/GaAs potential barrier with 300 meV height and 3 nm or 5 nm width, simulations are performed with various average electron energies and momentum deviations. The simulation results become closer to the theoretical phase time as the average electron energy decreases and as the momentum deviation decreases. It is also shown that a barrier, which is due to the peak spectrum shift in the momentum space after tunneling. (author). refs., figs.

• 대한음성학회:학술대회논문집
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• 대한음성학회 2005년도 추계 학술대회 발표논문집
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• pp.97-100
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• 2005

The aim of the present study is to compare the vowel formants between generations in Daegu dialect. 20 Daegu dialect speakers were participated in this study; 10 were in their 40's, the other 10were in their 20's. As a result, the distance of /ㅣ/ and /ㅐ/, and, /ㅡ/ and /ㅓ/ in 20's is further than 40's, while the distance of /ㅗ/ and in 20's is closer than 40's. It seems reasonable to conclude that vowels in Daegu dialect change to have their own stable space, but /ㅗ/ and /ㅜ/ does not.

• 터널과지하공간
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• 제6권1호
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• pp.30-38
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• 1996

A two dimensional analysis program for groundwater flow in fractured network was developed to analyze the influence of discontinuity characteristics on groundwater flow. This program involves the generation of discontinuities and also connectivity analysis. The discontinuities were generated by the probabilistic density function(P.D.F.) reflecting the characteristics of discontinuities. And the fracture network model was completed through the connectivity analysis. This program also involves the analysis of groundwater flow through the discontinuity network. The result of numerical experiment shows that the equivalent hydraulic conductivity increased and became closer to isotropic as the density and trace length increased. And hydraulic head decreased along the fracture zone because of much water-flow. The grouting increased the groundwater head around cavern. An analysis of groundwater flow through discontinuity network was performed around underground oil storage cavern which is now under construction. The probabilistic density functions(P.D.F) were obtained from the investigation of the discontinuity trace map. When the anisotropic hydraulic conductivity is used, the flow rate into the cavern was below the acceptable value to maintain the hydraulic containment. But when the isotropic hydraulic conductivity is used, the flow rate was above the acceptable value.

• International Journal of Internet, Broadcasting and Communication
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• 제16권3호
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• pp.164-169
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• 2024

The history of animals raised by humans began in prehistoric times, and in modern times they were classified as livestock and pets. As social awareness changes, the term 'companion animal' is used instead of 'pet', and related content has also become more diverse. Recently, digital contents such as virtual pet training, memorial space, and AI health diagnosis using metaverse and AI technology are developing. Developed digital content makes pet care convenient and provide emotional support and economic benefits to users. As technology develops and content becomes more diverse, the relationship between pets and humans will become closer in the future, and related laws and ethical guidelines will need to be established.

• 한국실내디자인학회논문집
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• 제18권5호
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• pp.183-190
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• 2009

Increase in the elderly population has given rise to various social problems throughout Korean society, and what is more, although the greater demand of medical treatment, its development is still in its early stages. Given that Specialized Geriatrics Hospital has stood amid a range of spatial complication and it should faithfully reflect the needs of elderly population, we need a better understanding of Specialized Geriatrics Hospital. This study suggested the foundation to plan of Specialized Geriatrics Hospital through analyzing and evaluating spatial configuration of Specialized Geriatrics Hospital by "Space Syntax" and "J-Graph" The study focused on Specialized Geriatric Hospitals existing in Korea which owned more than 100 beds. The result of this study is summarized as follows; First, the rate of separated convex showed that the portions of the Treatment of outpatients and Supply have increased, but onthe other hand the portion of the The ward has been on the decrease. Second, in the case of Treatment of outpatients, it was structured Tree-shaped and the Tree-shaped could be separated with two types: waiting room and wailing room with lounge. in the case of The ward, it was structured Tree-shaped and also Ring-shaped. The more recently opened Geriatrics Hospital, the closer to Ring-shaped. Third, the access to the Ccentral treatment was low though the access to the core of the each floor was high. Fourth, in the progress of intelligibility, the fact that its value has decreased is becoming a serious problem of medical development for the elderly population finally, according to J-graph's analysis, the hallway made the spatial depth of rooms and public space more deepened. This caused by scattered arrangement of public spaces. As the only planning were considered in this study, It therefore needs more diversified approaches considering physical factors such like real distance and area.

• 한국실내디자인학회논문집
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• 제26권4호
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• pp.30-41
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• 2017

Sunlight is perceived by human beings first through the epidermis to space, and is a non - material medium that provides physical awareness of space, diversified expression of spaces, and plenty experience. The purpose of this study is to investigate the characteristics of active building skin based on the inflow of natural light required by humans, looked through among the works of Jacques Herzog & Pierre de Meuron, which show the characteristics of active building skin, TEA(Tenerife Espacio de las Artes, 2008), Messe Basel New Hall (2013) and Elbphilharmonie (2016). First, the interaction between Sunlight and space is divided into spatial characteristics and sensitivities according to their concepts, properties, and characteristics. The characteristics of active skin by light are classified into a physical approach and a constructive approach. Second, (El Croquis 152/153) and analyzed the images, detail drawings, and elevations, and simulated them in 3D to express the relationship between light and active building skin. Third, the changes of light intensity, light color, and distribution of light according to the time of light entering and the skin are determined from 6:00 am to 6:00 pm. Fourth, the images taken from January 30th to February 7th, 2017 on the site were compared with the computer simulated images, and the relationship between active skin and light was compared. This study is to recognize the existence and necessity of light required for human being through the activated epidermis differentiated from the limited or closed epidermis focused on information transmission, I would like to emphasize that I would like to take a step closer to the necessity and possibility of new attempts and developments so that I can feel the various experiential spaces by.