• Solar Energy
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• v.7 no.2
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• pp.86-97
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• 1987

Natural convection in the annulus between a horizontal conducting tube and a cylinder with spacers has been studied by 2-dimensional numerical method with finite difference techniques. The effects of Rayleigh number, conductivities of conducting tube and spacer, and position of spacers were studied analytically. In case of vertical spacers, the maximum local Nusselt number appears at ${\theta}{\approx}50^{\circ}$ in a conducting tube and ${\theta}{\approx}30^{\circ}$ in an outer cylinder, The local Nusselt numbers show positive values on the lower spacer, but negative values on the surface of the upper spacer. In case of horizontal spacers, the flow over the spacer is more active than that of under the spacer as the Rayleigh number increases. The maximum local Nusselt appeares at ${\theta}=180^{\circ}$ in a conducting tube and at ${\theta}=0^{\circ}$ in an outer cylinder. The local Nusselt numbers show positive values on the upward surface, but negative values on the downward surface of spacer. As the dimensionless conductivity increases, the mean Nusselt number remarkably increases at $K_w/K_f<48$ and show almost even at $K_w/K_f{\ge}48$. The mean Nusselt number of a conducting tube with vertical spacers is 5.12 percent less and with horizontal spacers is 11.33 percent less than that of a conducting tube without spacer at $Ra=10^4$, Pr = 0.7 and $K_w/K_f=48$.

• The Journal of the Korea Contents Association
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• v.10 no.1
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• pp.202-212
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• 2010

The purpose of this study is at clarifying what the genre oriented characteristics of virtual reality programs are. For this, the tests of 'We Are Married' being broadcasted in 'Sunday, Sunday Night' Part 1 of MBC from episode 1 to 8. As a result of analysis, this program was mixing together virtuality and reality by placing the image of virtual couple's life and presentness of entertainers existing in reality appearing at the studio. Also, it was forming sympathy with users as it satisfies fantasy and sense of reality toward marriage by the entertainer couples showing love and conflict that may happen between real couples after setting various categories of couple types. Also, through the device for the public space to confess private feelings through television, it shows the boundary between public domain and private domain breaking up. Along with this, it has implemented amusement characteristics by inspiring enjoyment of users by a substituted satisfaction through various forms of impressions presented to spouse such as materials, effort, gesture or language, etc. Accordingly, the virtual reality program shows authenticity, fiction and amusement by being mixed together and we can see that such genre oriented characteristics act as important strategy appealing to users based on breakup of boundary and genre oriented ambiguity.

• The Journal of Korean Association of Computer Education
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• v.8 no.2
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• pp.61-73
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• 2005

Mobile games have emerged as the most innovative entertainment technology, adding new revenue streams, taking advantage of the potential of wireless applications and service offerings. Mobile games, like any other types of computer game, offer a unique value for users in providing an exciting digital experience in virtual worlds. Players can become empowered through the development of new characters and strategies within games to achieve rewarding successes against the computers and other players. In this paper, we attempt to examine the motives of adolescents for playing mobile games. Based on data collected from survey, we have identified Escape, Arousal and Fantasy, Challenge and Competition, Diversion and Relaxation, Social interaction as the key motivators for playing mobile games. We also investigated the extent to which use and gratifications are predicted by demographic factors as well as by gaming experience. Statistical results confirm that most of the demographic factors played critical roles in determining the level of motivations for playing games. The results from this research might give mobile game industry some useful guidelines for developing mobile edu-game and market expansion strategy.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.10
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• pp.72-82
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• 1999

The error diffusion algorithm is excellent for reproducing continuous gray-scale images to bianry images and also has good edge characteristics. However, it is well known that artifacts with objectionable patterns can occur in the halftoned images. On the other hand, a halftone algorithm using blue noise mask has been proposed. where the halftoning is achieved by a pixelwise comparison of gray-scale image with an array, the blue noise mask. It doesn't have pattern artifacts, but the halftoned image looks unclear because the quantization errors are not feedbacked compared to the error diffusion. In this paper, edge enhanced error diffusion which dithers the threshold with the blue noise mask is proposed. We show that the proposed algorithm can produce unstructured and edge enhanced halftone images. This algorithm is analyzed by the concept of an equivalent input image. The performace of the proposed algorithm is compared with that of the conventional halftoning by measuring the radially averaged power spectrum and edge correlation.

• Journal of the Korean Institute of Gas
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• v.8 no.3 s.24
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• pp.8-15
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• 2004

This paper presents von Mises stress, deformation, and rotating distortion moment characteristics of inner tank bottom plate as a function of a cryogenic temperature difference along the radial distance from the center area to the corner one. The calculated results show that the filling level of LNG at the beginning of the cool-down process is very important for the design safety analysis of the inner tank. Obviously the thermal loading by a temperature difference between the LNG vapor gas of $-80^{\circ}C$ and a LNG temperature of $-162^{\circ}C$ affects to the thermal related characteristics of the bottom plates and annular one. From the computed results, the temperature difference by a vapor gas and liquid of LNG may lead to the thermal instability of the bottom plate. This phenomenon may cause the system failure of an inner tank.

• Journal of Digital Convergence
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• v.11 no.11
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• pp.783-793
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• 2013

Neo-liberalism after IMF bailout made the Korean book market flushing with rose due to the alleged self-development books. Vision of self-development books under neoliberal social system is inevitably reduced to a means of capital pursuing commercialization in line with improving the competitiveness of privates through the development of human resources. Characteristics of self-development books, which attributes personal fail to personal responsibility and lack of essential element compared to others in a competitive society, trap individuals forced to choose into anxiety and helplessness. Self-development and healing is a complementary relationship. Human beings needs healing -healing humanities- in the process of self-development. Therefore, humanities should trigger developing and perceiving his own 'reflexive life skills'. Individual's sense of happiness in life and his own experience is very important, and the conscious relationship about their own feelings could elicit 'self-reinforcement'.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.12
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• pp.1111-1119
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• 2010

In this study, condensation heat transfer coefficients of R-410A were obtained in flattened tubes made from round tubes with an inner diameter of 5.0 mm. The saturation temperature was $45^{\circ}C$; the heat flux, 10 kW/$m^2K$; the mass flux, 100-400 kg/$m^2s$; and the quality, 0.2-0.8. The results showed that the effect of the aspect ratio on the condensation heat transfer coefficient depended on the flow pattern. For annular flow, the heat transfer coefficient increased as the aspect ratio increased. For stratified flow, however, the reverse was true: the pressure drop increased as the aspect ratio increased. Existing correlations adequately predicted the heat transfer coefficients and pressure drops of the flattened tubes.

• The Journal of the Convergence on Culture Technology
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• v.6 no.4
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• pp.31-37
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• 2020

This study examines the way poetry text is inserted in dramas and the way poets represent themselves through the drama "The climax" (2011). The drama features Lee Yuk-sa, a poet and independence activist, as a central figure and chooses a narrative structure that follows his life. The drama maximizes the lyricity and visual beauty of the drama by inserting his poems with fantastic images at the most dramatic moments of the poet's life. The image presented with the poem maximizes Lee Yuk-sa's intense hardship, while portraying the poem as a crystal of this hardship. Thus, the drama "The climax" uses Lee Yuk-sa's poetry to visualize the inner world of the central character Lee Yuk-sa. Lee Yuk-sa's poems are used in conjunction with his image to simultaneously represent the beauty of poetry and the upright spirit of the poet. This is the result of a balanced portrayal of Yi Yuk-sa, a poet and independence activist, as an intellectual who acts. The drama "The climax" is the main text that sincerely performed the representations of poems and poets through video.

• Applied Microscopy
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• v.29 no.2
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• pp.223-230
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• 1999

The epithelium of the rectum in the mosquito larvae, Culex pipiens pallens: Culicidae, was observed with electron microscope. The rectum of posterior hindgut was composed of epithelial tissue which were covered with cuticular intima on the luminal side, connective tissue and muscular tissue. The rectal epithelial cells were squamous absorptive cells, and apical plasma membranes were highly folded to form apical infoldings with mitochondria inserted them. The lateral plasma membranes were irregularly infolded and well developed mitochondria were found closely associated with infoldings . And intercellular spaces (or channels) were formed between the epithelial cells, whereas speptate junction was found near the apical zone between them. Also basal plasma membrane were infolded which made basal infoldings ('basal labyrinth'), and were covered with thin basal lamina. Rcetal epithelium was surrounded by the connective tissue which was contained axon and tracheole cells. Connective tissue was covered with the bundles of circular and longitudinal muscles.

• Archives of design research
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• v.12 no.4
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• pp.69-77
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• 1999

In creating an illustration, rather than depend on the subjective expression of the illustrator, one should consider the characteristics of child cognitive development. Illustrations should be those which can arouse child's interesting and which can be educational. To do this, first, characteristic expressions shown in children's pictures can be used to arouse child's interesting. In creating an illustration, one should consider sufficiently "intuitive form" and "representative form" in order to appeal to curiosity of child. Second, illustrations should be able to be helpful to the development of child's intellect, emotion and imagination. The form is desired to be adequately exaggerated or reduced feature, to have anthropomorphic figure and to be fantastic composition considering the egocentrism and animalism of the child. As mentioned above, it can be said characteristic expression in picture book illustrations are affected by the two points - fascinating expression drawn by child and expression by illustrator, which can be helpful to the development of intellect, emotion and imagination.otion and imagination.