• Title/Summary/Keyword: orthogonal functions

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Application of DINEOF to Reconstruct the Missing Data from GOCI Chlorophyll-a (GOCI Chlorophyll-a 결측 자료의 복원을 위한 DINEOF 방법 적용)

  • Hwang, Do-Hyun;Jung, Hahn Chul;Ahn, Jae-Hyun;Choi, Jong-Kuk
    • Korean Journal of Remote Sensing
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    • v.37 no.6_1
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    • pp.1507-1515
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    • 2021
  • If chlorophyll-a is estimated through ocean color remote sensing, it is able to understand the global distribution of phytoplankton and primary production. However, there are missing data in the ocean color observed from the satellites due to the clouds or weather conditions. In thisstudy, the missing data of the GOCI (Geostationary Ocean Color Imager) chlorophyll-a product wasreconstructed by using DINEOF (Data INterpolation Empirical Orthogonal Functions). DINEOF reconstructs the missing data based on spatio-temporal data, and the accuracy was cross-verified by removing a part of the GOCI chlorophyll-a image and comparing it with the reconstructed image. In the study area, the optimal EOF (Empirical Orthogonal Functions) mode for DINEOF wasin 10-13. The temporal and spatialreconstructed data reflected the increasing chlorophyll-a concentration in the afternoon, and the noise of outliers was filtered. Therefore, it is expected that DINEOF is useful to reconstruct the missing images, also it is considered that it is able to use as basic data for monitoring the ocean environment.

The numerical grid generation using the nearly orthogonal boundary-fitted curvilinear coordinate systems (근사직교 경계고정 곡선좌표계를 사용한 수치적 격자생성)

  • 맹주성;신종균
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.12 no.3
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    • pp.561-565
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    • 1988
  • In the present study, a new method of generating a nearly orthogonal boundary-fitted coordinate systems with automatic grid spacing control is introduced. Applications of the method to a two dimensional simply-connected region is then demonstrated. The nearly orthogonal boundary-fitted method has the following features, (a) Strong grid control in the .eta.-direction can be made, (b) The generated boundary-fitted coordinates are nearly orthoronal, (c) Both the .xi.-and .eta.-direction control function are mathematically derived. Especially the .eta.-direction control function is derived under the assumption that the .eta.-direction grid spacing is by far smaller than the .xi.-direction grid spacing when the .eta.-direction grid line is strongly clustered. (d) The grid control functions are dynamically adjusted by the metric scale factors imposed on the boundary. The control function is fully automatic and eliminates the need of user manipulation of the control function.

The Size Optimization Design of Crane using the Table of Orthogonal Array and Finite Element Analysis (직교배열표와 유한요소해석을 이용한 크레인의 치수최적설계)

  • 홍도관;최석창;안찬우
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.1471-1474
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    • 2003
  • The correlation between the object function and the design parameter is shown on this paper by using the characteristic function for tile mixed result of the structure analysis. tile buckling analysis and the table of orthogonal array according to the original crane's dimensional change. About the above two object functions, the effective of design change according to the change of design parameters could be estimated. Also, the crane's weight is reduced up to 20.58 percent maintaining the structural stability according to the thickness of plate.

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The Study of Neural Networks Using Orthogonal function System in Hidden-Layer (직교함수를 은닉층에 지닌 신경회로망에 대한 연구)

  • 권성훈;최용준;이정훈;유석용;엄기환;손동설
    • Proceedings of the IEEK Conference
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    • 1999.06a
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    • pp.482-485
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    • 1999
  • In this paper we proposed a heterogeneous hidden layer consisting of both sigmoid functions and RBFs(Radial Basis Function) in multi-layered neural networks. Focusing on the orthogonal relationship between the sigmoid function and its derivative, a derived RBF that is a derivative of the sigmoid function is used as the RBF in the neural network. so the proposed neural network is called ONN(Orthogonal Neural Network). Identification results using a nonlinear function confirm both the ONN's feasibility and characteristics by comparing with those obtained using a conventional neural network which has sigmoid function or RBF in hidden layer

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Modeling radon diffusion equation in soil pore matrix by using uncertainty based orthogonal polynomials in Galerkin's method

  • Rao, T.D.;Chakraverty, S.
    • Coupled systems mechanics
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    • v.6 no.4
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    • pp.487-499
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    • 2017
  • This paper investigates the approximate solution bounds of radon diffusion equation in soil pore matrix coupled with uncertainty. These problems have been modeled by few researchers by considering the parameters as crisp, which may not give the correct essence of the uncertainty. Here, the interval uncertainties are handled by parametric form and solution of the relevant uncertain diffusion equation is found by using Galerkin's Method. The shape functions are taken as the linear combination of orthogonal polynomials which are generated based on the parametric form of the interval uncertainty. Uncertain bounds are computed and results are compared in special cases viz. with the crisp solution.

Proper orthogonal decomposition in wind engineering - Part 1: A state-of-the-art and some prospects

  • Solari, Giovanni;Carassale, Luigi;Tubino, Federica
    • Wind and Structures
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    • v.10 no.2
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    • pp.153-176
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    • 2007
  • The Proper Orthogonal Decomposition (POD) is a statistical method particularly suitable and versatile for dealing with many problems concerning wind engineering and several other scientific and humanist fields. POD represents a random process as a linear combination of deterministic functions, the POD modes, modulated by uncorrelated random coefficients, the principal components. It owes its popularity to the property that only few terms of the series are usually needed to capture the most energetic coherent structures of the process, and a link often exists between each dominant mode and the main mechanisms of the phenomenon. For this reason, POD modes are normally used to identify low-dimensional subspaces appropriate for the construction of reduced models. This paper provides a state-of-the-art and some prospects on POD, with special regard to its framework and applications in wind engineering. A wide bibliography is also reported.

FINITE INTEGRALS ASSOCIATED WITH THE PRODUCT OF ORTHOGONAL POLYNOMIALS AND WRIGHT FUNCTION

  • Khan, Nabiullah;Khan, Mohammad Iqbal;Khan, Owais
    • Honam Mathematical Journal
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    • v.43 no.4
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    • pp.597-612
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    • 2021
  • Several useful and interesting extensions of the various special functions have been introduced by many authors during the last few decades. Various integral formulas associated with Wright function have been studied and a noteworthy amount of work have found in literature. The principal object of the present paper is to evaluate finite integral formulas containing the product of orthogonal polynomials with generalized Wright function. These integral formulas are expressed in terms of Srivastava and Daoust function. Some interesting particular cases are obtained from the main results by specialising the suitable values of the parameters involved.

Extended Quasi Orthogonal Functions for 3G CDMA Systems (3G CDMA 시스템을 위한 확장 준직교 함수)

  • Lee Kwang-Jae;Moon Myung-Ryong;Hou Jia;Lee Moon-Ho
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.16 no.7 s.98
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    • pp.697-708
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    • 2005
  • The forward link of the 3G CDMA system may become limited under the increasing of the number of users. The conventional channelization code, Walsh code, has not enough sizes f3r much possible users, therefore, the quasi orthogonal function(QOF), which process optimal crosscorrelation with Walsh code, is considered. In this paper, we investigate quasi orthogonal function on Jacket matrices, which can lead lower correlations values and better performance in 3G CDMA system. Moreover, to simplify the detector and improve the BER performance, a novel detection for QOF CDMA system is proposed. Finally, the simple recursive generation of the bent sequences for QOF mask function is discussed.

Unsupervised Incremental Learning of Associative Cubes with Orthogonal Kernels

  • Kang, Hoon;Ha, Joonsoo;Shin, Jangbeom;Lee, Hong Gi;Wang, Yang
    • Journal of the Korean Institute of Intelligent Systems
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    • v.25 no.1
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    • pp.97-104
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    • 2015
  • An 'associative cube', a class of auto-associative memories, is revisited here, in which training data and hidden orthogonal basis functions such as wavelet packets or Fourier kernels, are combined in the weight cube. This weight cube has hidden units in its depth, represented by a three dimensional cubic structure. We develop an unsupervised incremental learning mechanism based upon the adaptive least squares method. Training data are mapped into orthogonal basis vectors in a least-squares sense by updating the weights which minimize an energy function. Therefore, a prescribed orthogonal kernel is incrementally assigned to an incoming data. Next, we show how a decoding procedure finds the closest one with a competitive network in the hidden layer. As noisy test data are applied to an associative cube, the nearest one among the original training data are restored in an optimal sense. The simulation results confirm robustness of associative cubes even if test data are heavily distorted by various types of noise.