• Nuclear Engineering and Technology
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• v.15 no.4
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• pp.267-279
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• 1983

An analytical system has been established for scrutinizing both uranium- and plutonium-fueled lattices moderated by light water. This system consists of two primary codes. One is a unit cell program called KICC, which has theoretical foundation on the models of GAM and THERMOS incorporated with appropriate approximate treatments for various phenomena, whereas the other is a multi-dimensional diffusion-depletion program entitled KIDD. The adequacy of this system is verified by performing extensive benchmark calculations on a variety of critical experiments. The average value of effective multiplication factors for the selected nineteen UO$_2$ critical experiments of heterogeneous lattice structure is calculated to be 1.0006 with a standard deviation of 0.0039. Power distributions have also been calculated for some critical experiments fueled with both uranium and plutonium of varying concentrations. The maximum percentage difference between the measured and calculated power distributions appears to be less than 5%. This result, together with the previously reported result, illustrates that the KICC/KIDD system is a very effective tool for the analysis of a light water reactor core.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.3B
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• pp.408-422
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• 2000

In this paper, we propose a generalized vector channel model for wireless communication systems using antenna arrays. The proposed channel model reflects path loss. spatial-temporal variation of shadowing, multipath fading , Doppler effect, spatial distribution of local scatterers and delay spread due to remote dominant scatterers. In addition, we use a discrete ray model in which respective ray signal experiences independent shadowing, fading and Doppler shift, and impinges on antenna arrays at a distinct angle. Based on the proposed mode. we derive the relations on the spatial and temporal correlations of the received signals and implement a spatial channel simulator. By comparing the theoretical values with the simulated ones, we verify the effectiveness of the implemented simulator. The simulator is then used to generate an arbitrary channel impulse response and to analyze the channel characteristics under various environments.

• Journal of Korea Game Society
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• v.7 no.2
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• pp.21-32
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• 2007

It is significant to simulate scattering of light within media for realistic image synthesis; however, this requires costly computation. This paper introduces a practical image-space approximation technique for interactive subsurface scattering. We use a general two-pass approach, which creates transmitted irradiance samples onto shadow maps and computes illumination using the shadow maps. We estimate single scattering efficiently using a method similar to common shadow mapping with adaptive deterministic sampling. A hierarchical technique is applied to evaluate multiple scattering, based on a diffusion theory. We further accelerate rendering speed by tabulating complex functions and utilizing level of detail. We demonstrate that our technique produces high-quality images of animated scenes with blurred shadow at hundreds frames per second on graphics hardware. It can be integrated into existing interactive systems easily.

• School Mathematics
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• v.19 no.4
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• pp.795-817
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• 2017

Whereas noticing with relation to teacher expertise has been steadily studied in international contexts, there have been very few studies in Korea in this area. Given this, this paper reviewed the meanings of noticing based on Sherin and van Es as well as Jacobs et al. who provided foundational work and then analyzed recent studies on teacher noticing. A review of literature showed that recent international studies on noticing tend to elaborate the theoretical framework of noticing, diversify the methods of research on noticing, and extend to the range of noticing. This paper also included an analysis of domestic studies dealing with noticing either explicitly or implicitly. This paper is expected to serve as a basis to foster conceptual understanding of teacher noticing and to derive follow-up studies in Korea.

• Journal of Korean Society of Transportation
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• v.30 no.2
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• pp.127-136
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• 2012

Multi-car rear-end collision accidents have three categories: sequential collision from the rear which is commonly referred to as chain reaction collision, sequential collision from the front, and mixed-order collision. This paper suggests several effective methods of reconstruction analysis for multi-car rear-end collision accidents. First, by incorporating the traditional empirical method which uses vehicle damage caused by brake dive and passenger injuries, with results of theoretical analysis made within mechanics of rigid body, it is made possible for the method to be put to immediate practical use. A methodology to precisely analyze multi-car rear-end collision accidents was suggested using a simulation program simultaneously with a video event data recorder which is starting to be widely used in domestic vehicles. To go beyond the simple intuitive analysis of the video event data recorder, the simulation analysis based on the results of video analysis was executed to acquire various information, so that the causes and responsibility could be clearly stated.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.5
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• pp.935-943
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• 1988

The forming limit diagram is assessed as a means of estimating the forming characteristics of sheet metal and is usually determined experimentally. The strain rates used in the determination are likely to be low. However, often in practice, the strain rates are much higher, so if forming limit diagram is determined at low rates, it may not be appropriate. This paper reconsiders the forming limit diagram for mild steel and aluminum sheet up to variation in strain rate from 10$^{-2}$ sec to 20/sec where its forming has been carried out under oil pressure using a hydraulic bulge test with circular and elliptical dies. To obtain higher strain rate, an impact bulge test had been employed with the same die sets as those used for a hydraulic bulge test. The results obtained are as follows: (1) As the strain rate increases, the fracture pressure increases and the polar height at fracture decreases. (2) Experiment has shown that, in the positive quadrant of the forming limit diagram, the diagram is lowered with increasing strain rate and the effect of strain rate changes according to strain paths and materials..

• The Journal of the Korea Contents Association
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• v.3 no.2
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• pp.1-10
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• 2003

A semiotic approach to modem visual arts has emerged since French post-structuralism was introduced to Anglo -American academics by "deconstruction" or "postmodemi sm." It views a work of art as a sign, which is its math odical assumption and, at the same time, makes its appli cation more accessible. In the milieu of modem visual arts' effort to be intimate with general audience, modem art photography is now fared with the request to be a familar and universal domain, instead of being left only in photo books as artistic and academic achievements. More specifically, various photo images puter graphics to such megaexhibitions as "Gwangju Biennale,. "Media City Seo ul," and "Pusan International Art Festival," are main objects of study. A coherent and scientific analysis of visual semitotics is still on the way, however, it is an urgent task how to read and interpret a photo image with multiple meanings. This study argues that visual seniotics can be a powerful tool to enhance the understanding of art photography. After all, seniotics is a product of age； we live in the age of legibility, that is, of reading the work of art well as the social events and phenomena. art well as the social events and phenomena.

• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.1104-1111
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• 2017

In this study, the authors aimed to give careful consideration to the circulation of bioenergy (Qi) by using cardiorespiratory massage technique. Finding enlightenment in harmony with nature thousands of years ago, our ancestors created Qi using natural breathing and tried to achieve good health and long life by controling the up and down movement. Experiencing the importance of the abdomen during the hungry times, also, grandmothers cured diseases by rubbing the abdomen, which is the ocean of life with their soft, soothing touch of hand. Naval breathing therapy was formed, based on natural breathing, emotional recognition of grandmothers' soft, soothing touch, and the Theory of Unified Reason and Energy that is the key of Oriental medicine. Natural breathing and Yakson massage are kinds of naturopathy to change body and mind, cure diseases naturally, and maintain the improvement in physical functions by taking care of the abdomen through the creation of Qi and the up and down movement and keeping dynamic balance between the natural world and the inside and outside of human body. It is anticipated that this study could contribute to the practical spread for an active application of naval breathing therapy and be broadly used in scientific clinical researches.

• The Journal of the Korea Contents Association
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• v.19 no.10
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• pp.137-145
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• 2019

Eco-museums can be called "living museums" without walls covering specific areas. Eco-museums protect, preserve and display the integrity, completeness and protozoic of nature and cultural heritage, and emphasize the organic relationship between people and heritage. In 1971, the concept of "ecomuseum" was presented by Frenchman George Henry Rivier. "Environment" includes natural and human life. It then spread to Canada, Britain, the United States and China[1]. The first Ecological Museum and the concept of this study, the existing literature, high and each Su donghai, Hu chaoxiang and Liviere selects, six in the study of factors. Museum was analyzed by the ecology of the frame of analysis of several countries. According to the analysis results, the frame of this theory will not only be applicable to the research of the ecological museum in the ecological museum, but it will also be able to use this theory frame for the analysis of the ecological museum in China's minority areas in the future.

• Journal of the Korea Society of Computer and Information
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• v.5 no.3
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• pp.29-32
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• 2000

Layered video coding schemes allow the video information to be transmitted in multiple video bitstreams to achieve scalability. they are attractive in theory for two reasons. First, they naturally allow for heterogeneity in networks and receivers in terms of client processing capability and network bandwidth. Second, they correspond to optimal utilization of available bandwidth when several video qualify levels are desired. In this paper we propose a scalable video codec architectures with motion estimation, which is suitable for real-time audio and video communication over packet networks. The coding algorithm is compatible with ITU-T recommendation H.263+ and includes various techniques to reduce complexity. Fast motion estimation is Performed at the H.263-compatible base layer and used at higher layers, and perceptual macroblock skipping is performed at all layers before motion estimation. Error propagation from packet loss is avoided by Periodically rebuilding a valid Predictor in Intra mode at each layer.