• Journal of Korea Game Society
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• v.13 no.3
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• pp.85-94
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• 2013

In this paper, we propose a scheme to reduce the number of shadow tests conducted during rendering of ray tracing. The shadow test is a very important process in ray tracing to generate photo-realistic images. In the rendering phase, the ray tracer determines whether to cull the shadow test based on information calculated from a shadow test conducted on the kd-tree in the preprocessing phase. In conventional rendering process, the proposed method can be used with little modification. The proposed method is suitable for a static scene, in which the geometry and light source does not change in the same manner as it does in the conventional method. The validity of the proposed scheme is verified and its performance is evaluated during cycle-accurate simulation. Through experiment results, we found that we could reduce up to 17% of the shadow test.

• Journal of the Korean GEO-environmental Society
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• v.9 no.1
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• pp.11-16
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• 2008

In this paper, vertical earth pressure by CANDE program is compared with that by some equations such as the equation by Janssen, Marston, Spangler, and Handy to calculate vertical earth pressure with respect to several factors acting on a rigid buried-pipe filled cohesionless soil. As a result of comparative analysis of vertical earth pressure with each equation, primary factors are affected by backfill width, backfill depth and wall friction. Moreover, vertical earth pressure is linearly increased with backfill depth and width from results of the finite element method. Handy's Equation is reasonable for finite element method while Marston equation is overestimated in case of the design of buried-pipe and box.

• Journal of the Korean Ceramic Society
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• v.55 no.2
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• pp.153-159
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• 2018

Porous ceramic plates were prepared from Onggi clay and bamboo charcoal powder at 1100 and $1200^{\circ}C$ and their porous properties and water absorption, and the cooling effect of porous plates, were investigated to produce eco-friendly porous ceramics for a self-cooling system that relies on the evaporation of absorbed water. Porous properties were dependent on the particle size of charcoal powder pore forming additive and the firing temperature; properties were also found to be dependent on the total pore volume, average pore size and porosity, which had values of $0.103-0.243cm^3/g$, 0.81 - 2.56 mm and 20.9 - 38.2%, respectively, at $1100^{\circ}C$ and $0.04-0.18cm^3/g$, 0.33 - 2.03 mm and 10.8 - 30.9%, respectively, at $1200^{\circ}C$. Cooling temperature difference of flowing air parallel to surface of porous ceramic plates fired with two kinds of charcoal powder at $1100^{\circ}C$ was $3.5-3.6^{\circ}C$ at $26^{\circ}C$ and 60% of relative humidity in a closed box. Cooling temperature difference was dependent on the number of porous plates and the distance between porous plates. A simple and eco-friendly cooling system using porous ceramic plates fired from Onggi clay and charcoal powder was proposed.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.8
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• pp.879-885
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• 2008

A rotordynamic analysis was performed with a decant-type centrifuge, which is a kind of industrial centrifuge. The system is composed of screw rotor, bowl rotor, driving motors, gear box, and support rolling element bearings. These rotors have a rated speed of 4300 rpm, and were modeled utilizing a rotordynamic FE method for analysis, which was verified through 3-D FE analysis. Design goals are to achieve wide separation margins of lateral critical speeds, and favorable unbalance responses of the rotor in the operating range. Then, a complex analysis rotordynamic analysis of the system was carried out to evaluate its forward synchronous critical speeds and mode shapes, whirl natural frequencies, and unbalance responses under various balance grade. As a result of analysis, the rotordynamic analysis performed by separating a screw rotor and bowl rotor may cause an error in predicting critical speed of entire system. Therefore, the rotordynamic analysis of a coupled rotor combining a screw and bowl rotor must be performed in order to more accurately estimate dynamic characteristics of the decanter-type centrifuge as presented in this paper. Also, rolling element bearings with suitable stiffness should be selected to keep enough separation margin. In addition, in establishing balance grade of a screw and bowl rotor, ISO G2.5 balance grade is more recommended than ISO G6.3, in particular balancing correction of a screw rotor based on ISO G2.5 grade is strongly recommended.

• The Journal of Internal Korean Medicine
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• v.19 no.2
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• pp.278-299
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• 1998

This study was aimed to evaluate the anti-stress effect of danchisoyosan on the rats stressed by immobilization. The experimental animals were immobilized in the stress box($5{\times}5{\times}20cm$) for 12 hours in a day during 3 days, and administered $500mg/5m{\ell}/g$ of Danchisoyosan extract for 14 days before stress. There were measured the change of body weight and organ weight under immobilized-stress. The norepinephrine, epinephrine, dopamine, serotonine contents were measured by HPLC method in rat brain. There were measured the GOT, GPT contents in serum and tissue lipid peroxidation in the brain, liver, spleen, adrenalgland, pancreas, testes, thymus, heart. The following results were obtained: 1. The change of organ weight was significantly lower in control than normal group. Sample group inhibited decreased weight from stress comparing to control group. 2. Lipid peroxidation in the liver was significantly higher in control than normal group. Sample group shows significant decrease comparing to control group. 3. Lipid peroxidation in the kidney was significantly higher in control than normal group. Sample group shows significant decrease comparing to control group. 4. GPT contents in serum was significantly higher in control than normal group. Sample up shows significant decrease comparing to control group. 5. Dopamine contents in the brain was significantly higher in control than normal group. Sample group shows significant decrease comparing to control group. 6. Serotonine contents in the brain was significantly higher in control than normal group. Sample group shows significant decrease comparing to control group.

• Journal of the Korean Institute of Landscape Architecture
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• v.33 no.2 s.109
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• pp.32-47
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• 2005

This study was carried out to investigate and propose a green-wall system with evergreen plants for urban greening of Tongyeong City. To achieve these goals, the requirements and possibilities for wall greening were investigated and evaluated considering the location, topography, and climate of Tongyeong City. Existing walls were analyzed and then a suitable green wall system is proposed. Tongyeong City and its 151 islands covers the central and the southern parts of the Goseong peninsula. Most of the land is covered with hills and mountains; $43.9\%$ of the land area has a slope greater than $15\%$ and most hills and mountains near the urban area have a slope of more than $30\%$. As a result of the topographical properties, concrete retaining walls can often be seen along the streets in urbanized areas. These retaining walls are not only unattractive, but they also create environmental problems, and thus should be replaced with native evergreen plants. Options for replacing the retaining walls include evergreen vine-plants such as Hedaa spp. and Euonymus radicans, but native evergreen shrubs such as Pittosporum tobira, Nandina domestica, Raphiolepis umbellata, Ilex cornuta, flex crenata, Fatsia japonic, and Aucuba japonica may be a more attractive option. Current wall conditions are unsuitable for planting vines, therefore, a reservoir-drainage-type plant box filled with a light artificial substrate is required for greening these concrete retaining walls. These might be irrigated in the dry season and fertilized annually by an appropriate system. These plant boxes could be attached along the entire walls. An experiment investigating effects of substrates and bark-chip mulching on the growth of Hedera spp. showed that the mixture of cerasoil and field soil(v/v, 4:6) was superior to field soil alone and to the mixture of perlite small grain, large grain, and field soil(v/v/v, 2:2:6). Bark-chip mulching tended to increase the growth of Hedera spp..

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.277-280
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• 2011

After the concept of Cloud Computing was first introduced, IT industry had focused on it. The Cloud Computing market is increasing as many major coporations have been participating in it. Now, the possibility of Mobile Cloud Computing has rising. Needless to say, the growth of Mobile Cloud Computing is explosive. Mobile industry changes its operational system from FeaturePhone to SmartPhone which are based on iPhone or Android. The number of Smart phone users in Korea exceeds 10 millions. Through this study, we will examine sorts and acctual situations of available domestic and international Mobile Cloud Computing Services in SmartPhone. Also, we will investigate the problems of current Mobile Cloud Computing and present the solutions.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.76-79
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• 2010

lately, vehicle blackbox increasing importance and usability Is needed accuracy and variety of information. because, blackbox help to analyze the exact cause of the accident and use as objective evidence in vehicle-related crime. In the paper, to overcome the limitations of the existing black box, use various sensors and vehicle information blackbox store current state of the vehicle with OBD-II protocol using vehicle state information and store exact current location and direction information of the vehicle with Gyro sensor and GPS and use global time of GPS for synchronization of information. In addition, blackbox back the information up with wifi. because, when blackbox damaged, dirvers were able to verify the information.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.2
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• pp.263-274
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• 1996

Titanium dioxide ($TiO_{2}$) film has been widely used as anti-reflection coating for solar cells but not as masking oxide for metallisation and diffusion of impurities. In this paper we have investigated the properties of $TiO_{2}$ for possible incorporation into solar cell processing sequence. Thus the use of a spray deposition system to form the $TiO_{2}$ film and the characterisation of this film to ascertain its suitability to solar cell processing. The spray-on $TiO_{2}$ film was found to be resistant to all the chemicals used in conjunction with solar cell processing. The high temperature anealing (in oxygen ambient) of the spray-on $TiO_{2}$ film resulted in an increased refractive index, which indicated the growth of an underlying thin film of $SiO_{2}$ film for the passivation of silicon surface which would reduce the recombination activities of the fabricated device. Most importantly, the successful incorporation of the $TiO{2}$ film will lead to the reduction of the many high temperature processing steps of solar cell to only one.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.11
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• pp.2677-2685
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• 2013

Car running data collected from the vehicle is a native image data and sensing data of it. Hence, it can be used as a set of objective data based on which events that took place outside the car can be analyzed and determined. In this paper, we designed and implemented a emergency situation detection system to sense, store, and analyze signals related to car movements, driver's various operation states, collision pulse, etc when a car collision accident occurs on the actual road by sensing and analyzing the car movements and driver's operation status. The suggested system provides information on the driver's reaction right before the collision, operation state of the vehicle, and physical movement. The collected and analyzed data on vehicle running can be utilized to clarify the cause of a collision accident and to handle it in a just manner. Besides, it can contribute to grasping and correcting wrong driving habits of the driver and to saving.