• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.326-334
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• 2010

In this study, we provide a comprehensive review of the CIP(Constrained Interpolation Pro file/Cubic Interpolated Propagation) method with a pressure-based algorithm that is known as a general numerical solver for soled liquid, gas and plasmas. And also we introduce a body-fitted grid system(Soroban grid) for computation of strongly nonlinear marine hydrodynamic problems such as slamming water on deck, wave impact by green water. This grid system can keep the third-order accuracy in time and space with the help of the CIP method. The grid system consists of the straight lines and grid points. In the 2-dimensional grid case, each grid points moving in these lines like abacus - Soroban in Japanese. The length of each line can be different and the number of grid points in each line can be different. Mesh generation and searching of upstream departure point are very simple and possible to mesh-free treatment. To optimize computation of free-surface and multi-fluid flows, We adopt the C-CUP method. In most of the earlier computations, the C-CUP method was used with a staggered-grid approach. Here, because of the mesh free nature of the Soroban grid, we use the C-CUP method with a collocated-grid approach.

• Fire Science and Engineering
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• v.21 no.2 s.66
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• pp.36-41
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• 2007

In this study, we determined TBP(T-branched pipe) would be available in Fire Safety Codes with strength analyses. A common FEM Program(ABAQUS) was used as analyses method, and the analyses results were confirmed by strength tests of the T-branch pipe. As a result, we concluded that the T-branch pipe can be used safely. Further more, we determined what kind of stainless steel pipe can be used in place of carbon steel pipe(KS D 3507). The stainless steel pipe name Is KS D 3576(stainless steel pipe) 10S, so they can be applied for piping in fire protection system.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.1
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• pp.19-26
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• 2012

In this study the progressive collapse behavior of a moment frame with infill steel panels is evaluated using nonlinear static pushdown analysis. The analysis model is a two story two span structure designed only for gravity load, and the load-displacement relationship is obtained with the center column removed. To obtain local stress and strain as well as the global structural behavior, finite element analysis is conducted using ABACUS. Through the analysis the effect of the span length and the thickness of the steel plate on the progressive collapse behavior of the structure is investigated, and the effect of the dividing the infill panel using stud columns is also studied. According to the analysis results, the thickness of the panels required to prevent progressive collapse increases as the span length increases, and as the number of panel division increases the progressive collapse resisting capacity increases slightly but the effect is not significant. It is also observed that when the infill panel is installed in only a part of the span the progressive collapse resisting capacity is somewhat increased.

• Journal of the Korea Concrete Institute
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• v.22 no.1
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• pp.29-39
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• 2010

In this study, experimental test and numerical analysis were conducted to investigate the heat transfer characteristics and fiber performance of high strength concrete. The fire characteristics of the high strength concrete that couldn't be obtained through the test due to specific requirements and restrictions were forecast using numerical analysis approach. The outcome from the numerical analysis and the test were compared to verify and improve the reliability of the analysis. A numerical analysis of 80 and 100 MPa high strength concrete cases were carried out to identify the heat transfer characteristics and fire behavior using software, ABACUS (V6.8) From the results of verification experiment, a 25~55% level of beam shrinkage reduction was observed compared to the concrete without Fiber-Cocktail, indicating the improved fire resistance performance, which appeared to be attributable to the function of Fiber-Cocktail that was able to control the heat transfer characteristics and ultimately result in enhancing the fire resistance performance.

• Journal for History of Mathematics
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• v.25 no.4
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• pp.1-10
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• 2012

In Chinese mathematics, there have been two numeral systems, namely one in spoken language for recording and the other by counting rods for computations. They concerned with problems dealing with practical applications, numbers in them are concrete numbers except in the process of basic operations. Thus they could hardly develop a pure theory of numbers. In Song dynasty, 0 and TianYuanShu were introduced, where the coefficients were denoted by counting rods. We show that in this process, counting rods took over the role of the numeral system in spoken language and hence counting rod numeral system plays the role of that for abstract numbers together with the tool for calculations. Decimal fractions were also understood as denominate numbers but using the notions by counting rods, decimals were also admitted as abstract numbers. Noting that abacus replaced counting rods and TianYuanShu were lost in Ming dynasty, abstract numbers disappeared in Chinese mathematics. Investigating JianJie YiMing SuanFa(簡捷易明算法) written by Shen ShiGui(沈士桂) around 1704, we conclude that Shen noticed repeating decimals and their operations, and also used various rounding methods.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.1
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• pp.1-7
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• 2021

Investor mood from social media is gaining increasing attention for leading a price movement in stock market. Based on the behavioral finance theory, this study argues that sentiment extracted from social media using big data technique can predict a real-time (short-run) price momentum in Chinese stock market. Collecting Sina Weibo posts that related to COVID-19 using keyword method, a daily influential weighted sentiment factors is extracted from the sizable raw data of over 2 millions of posts. We examine one supervised and 4 unsupervised sentiment analysis model, and use the best performed word-frequency and BiLSTM mdoel. The test result shows a similar movement between stock price change and sentiment factor. It indicates that public mood extracted from social media can in some extent represent the investors' sentiment and make a difference in stock market fluctuation when people are concentrating on a special events that can cause effect on the stock market.