• Title/Summary/Keyword: complementary functions method

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Dynamic response of curved Timoshenko beams resting on viscoelastic foundation

  • Calim, Faruk Firat
    • Structural Engineering and Mechanics
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    • v.59 no.4
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    • pp.761-774
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    • 2016
  • Curved beams' dynamic behavior on viscoelastic foundation is the subject of the current paper. By rewritten the Timoshenko beams theory formulation for the curved and twisted spatial rods, governing equations are obtained for the circular beams on viscoelastic foundation. Using the complementary functions method (CFM), in Laplace domain, an ordinary differential equation is solved and then those results are transformed to real space by Durbin's algorithm. Verification of the proposed method is illustrated by solving an example by variating foundation parameters.

A unified method for stresses in FGM sphere with exponentially-varying properties

  • Celebi, Kerimcan;Yarimpabuc, Durmus;Keles, Ibrahim
    • Structural Engineering and Mechanics
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    • v.57 no.5
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    • pp.823-835
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    • 2016
  • Using the Complementary Functions Method (CFM), a general solution for the one-dimensional steady-state thermal and mechanical stresses in a hollow thick sphere made of functionally graded material (FGM) is presented. The mechanical properties are assumed to obey the exponential variations in the radial direction, and the Poisson's ratio is assumed to be constant, with general thermal and mechanical boundary conditions on the inside and outside surfaces of the sphere. In the present paper, a semi-analytical iterative technique, one of the most efficient unified method, is employed to solve the heat conduction equation and the Navier equation. For different values of inhomogeneity constant, distributions of radial displacement, radial stress, circumferential stress, and effective stress, as a function of radial direction, are obtained. Various material models from the literature are used and corresponding temperature distributions and stress distributions are computed. Verification of the proposed method is done using benchmark solutions available in the literature for some special cases and virtually exact results are obtained.

Two rectangular elements based on analytical functions

  • Rezaiee-Pajand, Mohammad;Karimipour, Arash
    • Advances in Computational Design
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    • v.5 no.2
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    • pp.147-175
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    • 2020
  • To achieve appropriate stresses, two new rectangular elements are presented in this study. For reaching this aim, a complementary energy functional is used within an element for the analysis of plane problems. In this energy form, the Airy stress function will be used as a functional variable. Besides, some basic analytical solutions are found for the stress functions. These trial functions are matched with each element number of degrees of freedom, which leads to a number of equations with the anonymous constants. Subsequently, according to the principle of minimum complementary energy, the unknown constants can be expressed in terms of displacements. This system can be rewritten in terms of the nodal displacement. In this way, two new hybrid-rectangular triangular elements are formulated, which have 16 and 40 degrees of freedom. To validate the outcomes, extensive numerical studies are performed. All findings clearly demonstrate accuracies of structural displacements, as well as, stresses.

CIS CODES OVER 𝔽4

  • Kim, Hyun Jin
    • Korean Journal of Mathematics
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    • v.28 no.2
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    • pp.285-294
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    • 2020
  • We study the complementary information set codes (for short, CIS codes) over 𝔽4. They are strongly connected to correlation-immune functions over 𝔽4. Also the class of CIS codes includes the self-dual codes. We find a construction method of CIS codes over 𝔽4 and a criterion for checking equivalence of CIS codes over 𝔽4. We complete the classification of all inequivalent CIS codes of length up to 8 over 𝔽4.

Camparision and Analysis about the Weighted-Ordinate Colorimetric Method and the Direct Colorimetric Method of Halftone Dot Printing Colors (망점색인쇄물의 분광측색법과 자극치직독측색법에 대한 비교분석)

  • SangNamLee
    • Journal of the Korean Graphic Arts Communication Society
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    • v.6 no.1
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    • pp.13-39
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    • 1988
  • Test colors are halftone dot printed at the rate of 10% halftone dot area by process inksblack, cyan, magenta and yellow ink. Reproduced colors are measured by the weighted-ordinate colorimetric method and the direct colorimetric method. The weighted-ordinate colorimetric method compare favorably with the direct colorimetric method, because the former has good regular changes of tristimuIus values, chromacity coordinates, excitation purities, value functions and has smaller errors of dominant and complementary wavelengths than the latter. All test colors classify with the Munsell renotation.tation.

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Enhancement of Signal-to-noise Ratio Based on Multiplication Function for Phi-OTDR

  • Li, Meng;Xiong, Xinglong;Zhao, Yifei;Ma, Yuzhao
    • Current Optics and Photonics
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    • v.2 no.5
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    • pp.413-421
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    • 2018
  • We propose a novel methodology based on the multiplication function to improve the signal-to-noise ratio (SNR) for vibration detection in a phi optical time-domain reflectometer system (phi-OTDR). The extreme-mean complementary empirical mode decomposition (ECEMD) is designed to break down the original signal into a set of inherent mode functions (IMFs). The multiplication function in terms of selected IMFs is used to determine a vibration's position. By this method, the SNR of a phi-OTDR system is enhanced by several orders of magnitude. Simulations and experiments applying the method to real data prove the validity of the proposed approach.

Parameter estimation of linear function using VUS and HUM maximization (VUS와 HUM 최적화를 이용한 선형함수의 모수추정)

  • Hong, Chong Sun;Won, Chi Hwan;Jeong, Dong Gil
    • Journal of the Korean Data and Information Science Society
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    • v.26 no.6
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    • pp.1305-1315
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    • 2015
  • Consider the risk score which is a function of a linear score for the classification models. The AUC optimization method can be applied to estimate the coefficients of linear score. These estimates obtained by this AUC approach method are shown to be better than the maximum likelihood estimators using logistic models under the general situation which does not fit the logistic assumptions. In this work, the VUS and HUM approach methods are suggested by extending AUC approach method for more realistic discrimination and prediction worlds. Some simulation results are obtained with both various distributions of thresholds and three kinds of link functions such as logit, complementary log-log and modified logit functions. It is found that coefficient prediction results by using the VUS and HUM approach methods for multiple categorical classification are equivalent to or better than those by using logistic models with some link functions.

Three Dimensional Interlaminar Stress Analysis of a Composite Patch Using Stress Functions (응력함수를 이용한 복합재 적층 패치의 3차원 층간 응력 해석)

  • Lee, Jae-Hun;Cho, Maeng-Hyo;Kim, Heung-Soo
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2009.04a
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    • pp.488-491
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    • 2009
  • 본 논문에서는 응력함수와 Kantorovich method를 이용하여 기저판(substrate)에 인장과 굽힘이 작용할 때 복합재 패치의 3차원 응력을 해석하였다. 면내 방향과 면외 방향의 두 응력함수에 가상 공액일의 법칙(Complementary virtual work principle)을 적용하였으며 복합재 패치의 자유 경계조건과 바닥의 기저판으로부터 전달되는 전단 수직 응력 조건을 부여하였다. 이를 통해서 패치 구조물의 지배방정식을 연립 미분 방정식 형태의 고유치 문제로 변환하여 응력함수를 구하였다. 위 방법의 타당성과 효용성을 검증하기 위한 수치 예제로 cross-ply, angle-ply, quasi-isotropic의 패치 적층 배열을 고려하였으며, 층간 응력함수 값이 자유 경계에서 최고치를 나타내고 패치 중심부로 갈수록 급격히 감소하는 모습을 확인하였다. 제안된 기법은 기저판에 인장하중이 작용하는 경우뿐만 아니라 굽힘 하중이 작용하는 경우에도 정확한 예측이 가능하여, 패치 구조물의 층간 응력을 포함한 3차원 응력을 해석하는데 있어서 효율적인 해석 도구로서 사용할 수 있을 것이라 사료된다.

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A Complementary Quadtree in Consideration for Gradient of Homogeneous Regions (동질 영역의 기울기를 고려한 상보 쿼드트리)

  • Kim, Sin-Jin;Lee, Jong-Yeop;Kim, Yeong-Mo;Go, Gwang-Sik
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.39 no.3
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    • pp.36-41
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    • 2002
  • Generally, cartoon images are simple and involve a small number of colors and often include large homogeneous regions with same color or gradient. In this paper, effective compression method for complementary quadtree was suggested for cartoon images, by using those properties. And with progressive transmission, this method involves a progressive increase in the image resolution at the receiver from a lower to a higher resolution during the transmission of data. This is an effective way of using a limited transmission channel, because, after estimating the value of the data in the early transmission period, a decision can be made whether or not to proceed with the transmission of the remaining part. Since the proposed method is lossless and involves progressive transmission, it was compared with progressive PNG and progressive GIF, which had same functions.

COMPOUNDED METHOD FOR LAND COVERING CLASSIFICATION BASED ON MULTI-RESOLUTION SATELLITE DATA

  • HE WENJU;QIN HUA;SUN WEIDONG
    • Proceedings of the KSRS Conference
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    • 2005.10a
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    • pp.116-119
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    • 2005
  • As to the synthetical estimation of land covering parameters or the compounded land covering classification for multi-resolution satellite data, former researches mainly adopted linear or nonlinear regression models to describe the regression relationship of land covering parameters caused by the degradation of spatial resolution, in order to improve the retrieval accuracy of global land covering parameters based on 1;he lower resolution satellite data. However, these methods can't authentically represent the complementary characteristics of spatial resolutions among different satellite data at arithmetic level. To resolve the problem above, a new compounded land covering classification method at arithmetic level for multi-resolution satellite data is proposed in this .paper. Firstly, on the basis of unsupervised clustering analysis of the higher resolution satellite data, the likelihood distribution scatterplot of each cover type is obtained according to multiple-to-single spatial correspondence between the higher and lower resolution satellite data in some local test regions, then Parzen window approach is adopted to derive the real likelihood functions from the scatterplots, and finally the likelihood functions are extended from the local test regions to the full covering area of the lower resolution satellite data and the global covering area of the lower resolution satellite is classified under the maximum likelihood rule. Some experimental results indicate that this proposed compounded method can improve the classification accuracy of large-scale lower resolution satellite data with the support of some local-area higher resolution satellite data.

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