• Title/Summary/Keyword: Approximate Calculation

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An efficient 3D inversion of magnetotelluric data

  • Han, Nu-Ree;Choi, Ji-Hyang;Nam, Myung-Jin;Kim, Hee-Joon;Lee, Tae-Jong;Song, Yoon-Ho;Suh, Jung-Hee
    • 한국지구물리탐사학회:학술대회논문집
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    • 2007.06a
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    • pp.261-266
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    • 2007
  • An efficient three-dimensional (3D) inversion of magnetotelluric (MT) data can be carried out by using approximate sensitivities or avoiding the calculation of a full sensitivity matrix. In this paper, we propose approximate sensitivities for efficient 3D MT inversion based on the Gauss-Newton method and test and compare four kinds of sensitivities. Applying the four sensitivities to both synthetic and field data shows that the effects of sensitivities are highly dependent on data and thus applying various combinations of sensitivities is recommended for efficient inversion and good images.

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A Study on the Natural Period Estimation for the Buildings of Upper Wall and Lower Frame Type (상부벽식-하부골조를 가진 복합구조물의고유주기 산정에 관한 연구)

  • 박기수
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 1999.10a
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    • pp.170-177
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    • 1999
  • The natural period calculation equations specified in the current building code are empirical formulas that depend on height and material type of the structure. Building with the upper wall and lower frame type is a unique structure which composed of two different structural system This type of structure needs either the deep transfer girder or the thick transfer plate that brings the sudden change of stiffness and mass. Therefore the natural period equations recommended by the current code can not be applied directly. In this study the natural period of building with typical plan obtained by dynamci analysis is compared with that of various codes. Ad approximate estimation equation for the natural period of building with the upper wall and lower frame type obtained by regression analysis is recommended. by the current code can not be applied directly. In this study the natural period of building with typical plan obtained by dynamic analysis is compared with that of various codes, And approximate estimation equation for the natural period of building with the upper wall and lower frame type obtained by regression analysis is recommended.

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Closed-form solution of axisymmetric deformation of prestressed Föppl-Hencky membrane under constrained deflecting

  • Lian, Yong-Sheng;Sun, Jun-Yi;Dong, Jiao;Zheng, Zhou-Lian;Yang, Zhi-Xin
    • Structural Engineering and Mechanics
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    • v.69 no.6
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    • pp.693-698
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    • 2019
  • In this study, the problem of axisymmetric deformation of prestressed $F{\ddot{o}}ppl-Hencky$ membrane under constrained deflecting was analytically solved and its closed-form solution was presented. The small-rotation-angle assumption usually adopted in membrane problems was given up, and the initial stress in membrane was taken into account. Consequently, this closed-form solution has higher calculation accuracy and can be applied for a wider range in comparison with the existing approximate solution. The presented numerical examples demonstrate the validity of the closed-form solution, and show the errors of the contact radius, profile and radial stress of membrane in the existing approximate solution brought by the small-rotation-angle assumption. Moreover, the influence of the initial stress on the contact radius is also discussed based on the numerical examples.

Approximation Equation for Broad Bandwidth Antenna Design Using CMMS

  • Min, Kyeong-Sik;Lee, Ji-Chul
    • Journal of electromagnetic engineering and science
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    • v.10 no.4
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    • pp.296-302
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    • 2010
  • This paper proposes an approximate equation for broad bandwidth conditions in an antenna feeding probe design with a cylindrical magneto material structure (CMMS). The bandwidth calculation has been conducted according to the relation between the distance ($r_m$) between the magneto material and feeding probe, and the magneto material thickness ($t_m$) for a given ${\mu}_r$. The bandwidth of a proposed antenna with CMM feeding structure is improved about 182 %, when ${\mu}_r=20+j0.001$, in comparison with the bandwidth of an antenna without CMMS. The maximum error extent between the bandwidth calculated by the approximation equation and by the numerical calculation of the proposed antenna is about $\pm$3.2 % for ${\mu}_r=10+j0.001$. The approximation equation proposed in this study can solve the conventional problem of the complex process and the long time required for reiterative calculation, and allow simple and precise design with prediction. The accuracy of an approximated equation is compared with the results calculated by a commercial tool and verified by reasonable agreement between them.

An Implementation of Knowledge-based BIM System for Representing Design Knowledge on Massing Calculation in Architectural Pre-Design Phase (건축기획 매스 규모산정의 설계지식 재현을 위한 지식기반 BIM 시스템 구현)

  • Lee, Byung-Soo;Ji, Seung-Yeul;Jun, Han-Jong
    • Korean Journal of Computational Design and Engineering
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    • v.21 no.3
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    • pp.252-266
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    • 2016
  • An architectural pre-design, which is conducted prior to the architecture design, supports fundamental configuration during the entire AEC project by predicting the cost, demand, etc., of the building, and is therefore gaining importance. In particular, the massing calculation of the pre-design phase should be prioritized, as it is fundamental to architectural outline. However, most architects depend on only their experience and intuition while conceptualizing an integrated framework of design conditions, including the building code and requirements for the massing calculation of the object. Therefore, many difficulties arise in terms of performing appropriate tasks. Thus, the purpose of this study is to implement a knowledge-based BIM for explicitly representing the design knowledge, which is the basis of decision making for an architect while performing the massing calculation. In particular, the 3D knowledge relevant to a project can be provided and accumulated in the massing calculation by the BIM system; this facilitates an integral understanding. Consequently, the approximate result of massing calculation in 3D BIM environment, through both the knowledge-based BIM template and plug-in, can be swiftly provided to the architect. In addition, the architect can invent various alternatives, estimate resulting costs, and reuse the accumulated knowledge in future BIM design processes.

Estimation of Large Amplitude Motions and Wave Loads of a Ship Advancing in Transient Waves by Using a Three Dimensional Time-domain Approximate Body-exact Nonlinear 2nd-order BEM (3 차원 시간영역 근사비선형 2 차경계요소법에 의한 선체의 대진폭 운동 및 파랑하중 계산)

  • Hong, Do-Chun;Hong, Sa-Young;Sung, Hong-Gun
    • Journal of the Society of Naval Architects of Korea
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    • v.47 no.3
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    • pp.291-305
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    • 2010
  • A three-dimensional time-domain calculation method is of crucial importance in prediction of the motions and wave loads of a ship advancing in a severe irregular sea. The exact solution of the free surface wave-ship interaction problem is very complicated because of the essentially nonlinear boundary conditions. In this paper, an approximate body nonlinear approach based on the three-dimensional time-domain forward-speed free-surface Green function has been presented. The Froude-Krylov force and the hydrostatic restoring force are calculated over the instantaneous wetted surface of the ship while the forces due to the radiation and scattering potentials over the mean wetted surface. The time-domain radiation and scattering potentials have been obtained from a time invariant kernel of integral equations for the potentials which are discretized according to the second-order boundary element method (Hong and Hong 2008). The diffraction impulse-response functions of the Wigley seakeeping model advancing in transient head waves at various Froude numbers have been presented. A simulation of coupled heave-pitch motion of a long rectangular barge advancing in regular head waves of large amplitude has been carried out. Comparisons between the linear and the approximate body nonlinear numerical results of motions and wave loads of the barge at a nonzero Froude number have been made.

A Study on the Using of Chosun-Sanhak for the Enriched Learning about Pi (원주율에 대한 심화학습을 위한 조선산학의 활용 연구)

  • Choi, Eunah
    • Journal of Educational Research in Mathematics
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    • v.27 no.4
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    • pp.811-831
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    • 2017
  • The purpose of this study is to analyze the contents of pi of Chosun-sanhak and organize the teaching and learning activities to help to understand the concept of pi deeply using the analysis results. The results of this study are as follows. First, Chosun-sanhak used various approximate values of pi and those were represented as the form to reveal the meaning of the ratio of radius and circumference. Second, There were the freedom of selection of the approximate values of pi suitably. Lastly, the enriched leaning about pi need to draw a distinction pi from approximate values of pi, choose the suitable approximate values of pi and compare the method of calculation of circumference and the area of circle of Chosun-sanhak and today's mathematics. In conclusion, I proposed several issues which is worth exploring further in relation to pi and Chosun-Sanhak.

An Analysis of Bit Error Probability of Reed-Solomon/Convolutional Concatenated Codes (Reed-Solomon/길쌈 연쇄부호의 비트오율해석)

  • 이상곤;문상재
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.30A no.8
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    • pp.19-26
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    • 1993
  • The bit error probability of Reed-Solomon/convolutional concatenated codes can be more exactly calculated by using a more approximate bound of the symbol error probability of the convolutional codes. This paper obtains the unequal symbol error bound of the convolutional codes, and applies to the calculation of the bit error probability of the concatenated codes. Our results are tighter than the earlier studied other bounds.

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EXISTENCE OF PERIODIC SOLUTIONS TO LIAPUNOV CHARACTERISTIC INDEX EQUATIONS

  • Wang, Han You;Ouyang, Jun;Yao, Zhuo
    • Journal of the Chungcheong Mathematical Society
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    • v.19 no.2
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    • pp.123-131
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    • 2006
  • In this paper, a numerical programming for Liapunov index of differential equations with periodic coefficients depending on parameters is given. The associated equations are given at first, then existence of periodic solutions to the associated equations is proved in this paper. And we compute periodic solution u(t) of the associated equations. Finally, we give the error of approximate calculation.

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A new CAD-compatible non-quasi-static MOS tansient model (새로운 CAD용 Non-Quasi-Static MOS 과도 전류 모델)

  • 권대한;류윤섭;김기혁;황성우
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.34D no.12
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    • pp.31-38
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    • 1997
  • A new CAD-compatible non-quasi-static (NQS) MOS transient model is presented. A new type of weighted residual method, the collcoatin method, is adopted to obtian an approximate ordinary differntial equation from the continuity eqation. Contrasting to the conventional NQS models, the new model can directly include the variatin of the depletion charge and the derived transient current sare expressed with only physically meaningful variables. The new model predicts transient behaviors reasonably well in the calculation including cutoff regions where the depletion charge rapidly changes.

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