• Title, Summary, Keyword: Numerical

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SOME OBSERVATIONS ON THE NUMERICAL INDEX AND THE POLYNOMIAL NUMERICAL INDEX

  • Kim, Sun Kwang
    • Bulletin of the Korean Mathematical Society
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    • v.53 no.1
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    • pp.119-126
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    • 2016
  • In this paper, we study both the numerical index and the polynomial numerical index. First, we give a sufficient condition for a Banach space X to have lushness. Second, we study the relation between the renormings of a Banach space and the k-order polynomial numerical index. This shows that every real Banach spaces of dimension greater that 1 can be renormed to have 2-order polynomial numerical index ${\alpha}$ for any ${\alpha}{\in}[0,1/18)$.

Analysis of Hydraulic Characteristics in the Middle Reaches of Nak-Dong River using 2-Dimensional Numerical Analyis Model (2차원 수치해석모형을 이용한 낙동강 중류구간의 하천흐름 해석)

  • Han, Sung-Dea;Choi, Hyun;Ahn, Chang-Hwan;Lee, Je-Yun
    • Proceedings of the Korea Water Resources Association Conference
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    • pp.1732-1736
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    • 2008
  • The characteristics of a river flow analysis are significant for river maintenance plan. At the present time, HEC-RAS, 1-Dimensional Numerical Analysis Model, is mainly applied to analyze the character of a river flow. The shape of a river is somewhat in longitudinal linear form. It was suspected that the usage of 1-dimensional numerical analysis model is more economical. Development of numerical analysis models and computers are possible to calculate large volume. Hence, it is possible to adapt the analysis of the key stations by 2-dimensional numerical analysis model. The limitation of 1-Dimensional Numerical Analysis Model is that it is hard to evaluate structure affection of numerical simulation by energy loss coefficient at river structure analyzing. When adaptation of the 2-dimensional numerical analysis model in river structure ensues, it takes more objective analyzing than 1-dimensional numerical analysis model for flow affection by river structure. 2-dimensional numerical analysis model consults with the different structure position of hydraulic characteristics and different water depth of shape and scope in vertical flow. 1-dimensional numerical analysis model is possible to simulate with only energy loss coefficient for sudden river section changing, sudden waterway changing by curved. 2-dimensional numerical analysis model use original geographical features. So the model removes technical subjectivity of faulty judgment. It is an objective analysis.

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ON NUMERICAL RANGE AND NUMERICAL RADIUS OF CONVEX FUNCTION OPERATORS

  • Zaiz, Khaoula;Mansour, Abdelouahab
    • Korean Journal of Mathematics
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    • v.27 no.4
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    • pp.879-898
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    • 2019
  • In this paper we prove some interesting inclusions concerning the numerical range of some operators and the numerical range of theirs ranges with a convex function. Further, we prove some inequalities for the numerical radius. These inclusions and inequalities are based on some classical convexity inequalities for non-negative real numbers and some operator inequalities.

The study on the possibility of performance analysis for the compressive member using the numerical method (수치해석법을 활용한 압축부재 성능 해석의 가능성에 대한 연구)

  • Kim, Gwang-Chul
    • Journal of the Korea Furniture Society
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    • v.21 no.1
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    • pp.26-39
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    • 2010
  • This is a leading study to replace the structural analysis methodology on the specific traditional joint by a numerical analysis. Tests were carried out to test the compressive methodologies with the numerical results. The Japanese larch was used as a sample. The Orthotropic property of wood was specifically considered for the finite element numerical analysis. Linear numerical analysis and non-linear numerical analysis for the BEAM element and the two SOLID elements of ANSYS were used to analyze the compressive performance. In addition, more finely divided elements were used to raise the accuracy of the numerical result. Finally, the statistically significant differences were tested between that of the analytical and numerical results. It could be concluded that the SOLID 64 element shows the most optimum result when the non-linear analysis with the more finely divided element was used. However, finely dividing of the element is a considerable time consuming process, and it is quite difficult to raise the accuracy of the non-linear numerical analysis. Therefore, if considering the vertical displacement to be of the only interest, the BEAM element is more efficient than the SOLID element because the BEAM element is reflected as a simple line, which is less time consuming and difficult in dividing the elements. But, the BEAM element cannot accurately model the knot as a strength defect factor which is an important property in the orthotropic property of wood. Therefore, the SOLID element should be used to model the strength defect factor, knot, as it can be efficiently applied on the structural size flexure member which could be more strongly effected by the knot. In addition, it is useful at times when the failure types of members are to be more closely investigated, as the SOLID element is able to examine the local stress distribution of the member. The conclusion drawn by this study is of the good concordance between analytical results and numerical results of compressive wood members, but how orthotropic properties should only be considered. The numerical analysis on the specific Korean traditional joints will be based on the current study results.

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A Comparative Study on Hydraulic Characteristics of Curved Channel by Hydraulic Model Experiments and Numerical Analysis (수리모형과 수치해석을 통한 만곡부 하천의 수리학적 특성 비교 고찰)

  • Seo, Dong-Il;Choi, Han-Kuy
    • Journal of Industrial Technology
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    • v.27 no.A
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    • pp.85-94
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    • 2007
  • This study, regarding curved channel, was performed to compare and analyze hydraulic characteristics and the speed of water and water level for left bank and right bank through hydraulic model experiments and numerical analysis. Real channels that had characteristics of curved channel were selected as objectives. In order to easily operate one and two dimensional numerical analysis and comparison for total 2.4Km model channel, measuring point was set up as 200m. HEC-RAS model was applied as one dimensional numerical analysis program and SMS model was used as two dimensional numerical analysis program. In respect of speed of water, the average speed of water for right bank recorded 8.33m/s in a model experiment and 3.08m/s, 8.57m/s were average speed of water for right bank in one dimensional and two dimensional numerical analysis. The average speed of water of two dimensional numerical analysis was quite similar to that of model experiments. Also, as for water level, maximum observational errors between one and two dimensional numerical analysis for right and left bank of model experiments were 0.66m, 0.84m and 0.28m, 0.48m for each. It was found that two dimensional numerical analysis had a similar result to hydraulic model experiments. Accordingly, from the result of this study, two dimensional numerical analysis should be used rather than one dimensional numerical analysis, when numerical analysis for curved channel is conducted.

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NUMERICAL SIMULATIONS OF GALAXY FORMATION

  • Peiran, Sebastien
    • Publications of The Korean Astronomical Society
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    • v.25 no.3
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    • pp.71-76
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    • 2010
  • The current status of numerical simulations of galaxy formation is reviewed. After a description of the main numerical simulation techniques, I will present several applications in order to illustrate how numerical simulations have improved our understanding of the galaxy formation process.

Numerical Solutio of Inverse Problem of Fuzzy Modeling with Pseudo First Order Approzimation

  • Ikoma, Norikazu;Hirota, Kaoru
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • pp.1230-1233
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    • 1993
  • Numerical solution of inverse problem of Takagi-Sugeno fuzzy model is proposed. The method is located on the application of numerical optimization to the fuzzy model. Steepest descent method is used for the numerical optimization. We use the linear approximation of fuzzy model, called pseudo first order approximation, by fixing the membership value on the neighborhood of the corresponding input. It is introduced in order to reduce the difficulty of optimization process. The efficiency of this method is shown by a numerical experiment.

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Validation of Numerical Codes Applied to Floating Offshore Structures

  • Choi, Hang S.
    • Journal of Hydrospace Technology
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    • v.2 no.1
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    • pp.55-64
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    • 1996
  • Herein a review is made on the validation problem of numerical codes applied to floating offshore structures. Since the dynamic behaviour of offshore floating structures in water waves is in general complex and nonlinear, a numerical approach seems to be promising. However, numerical codes are likely involved with uncertainties and they at the present status show apparent scatterness in typical bechmark tests, particularly in second-order wave forces. Convergence test is the minimum requirement for the validation of numerical codes. Some other practical check points are introduced to clarify the potential error sources. It is concluded that a standard procedure for validation must be urgently established sothat numerical methods can safely be used as a rational design tool.

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Role of Supercomputers in Numerical Prediction of Weather and Climate (기상 및 기후의 수치예측에 대한 슈퍼컴퓨터의 역할)

  • Park, Seon-Ki
    • Atmosphere
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    • v.14 no.4
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    • pp.19-23
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    • 2004
  • Progresses in numerical prediction of weather and climate have been in parallel with those of computing resources, especially the development of supercomputers. Advanced techniques in numerical modeling, computational schemes, and data assimilation cloud not have been practically achieved without the aid of supercomputers. With such techniques and computing powers, the accuracy of numerical forecasts has been tremendously improved. Supercomputers are also indispensible in constructing and executing the synthetic Earth system models. In this study, a brief overview on numerical weather / climate prediction, Earth system modeling, and the values of supercomputing is provided.