Leong Wah June
Universiti Putra Malaysia
Davidon–Fletcher–Powell formulaDiagonal matrixQuasi-Newton methodNonlinear programmingGradient methodLocal convergenceRain gaugeMathematical optimizationRandom searchDiagonalBroyden–Fletcher–Goldfarb–Shanno algorithmMathematical analysisMonsoonOptimization problemLinear algebraMean absolute percentage errorGradient descentMeteorologyNonlinear systemGeneralized method of momentsEstimation theoryNewton fractalDerivation of the conjugate gradient methodJacobian matrix and determinantHessian matrixNonlinear conjugate gradient methodScale (ratio)Mathematics Subject ClassificationApplied mathematicsDerivative-free optimizationUnconstrained optimizationOptimization methodsRectangular pulseMathematicsEnvironmental scienceFeature (machine learning)Computer scienceMoment (mathematics)Numerical analysisCategorical variableSymmetric rank-oneConvergence (routing)Cluster analysisHydrology (agriculture)Broyden's methodConjugate gradient methodPattern searchNewton's methodBiconjugate gradient methodConjugate residual method
8Publications
4H-index
79Citations
Publications 8
Newest
#1Nur Allysa Mohd Redzuan Chan (UPM: Universiti Putra Malaysia)
#2Wendy Ling Shinyie (UPM: Universiti Putra Malaysia)H-Index: 1
Last. Leong Wah June (UPM: Universiti Putra Malaysia)H-Index: 4
view all 3 authors...
Stochastic rainfall model can be very useful to solve problem related in hydrology, agricultural science, and engineering. The objective of this study is to study the hourly rainfall in Peninsular Malaysia, to estimate the parameters of the models using the generalized method of moments (GMM), and to identify the performance of Bartlett Lewis rectangular pulse model (BLRPM) for the rainfall data using mean absolute percentage error (MAPE). Hourly rainfall datasets of five raingauge stations whic...
#3Leong Wah JuneH-Index: 4
Last. Azfi Zaidi Mohammad SofiH-Index: 2
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In this paper we present a new search direction known as the CG-BFGS method, which uses the search direction of the conjugate gradient method approach in the quasi-Newton methods. The new algorithm is compared with the quasi-Newton methods in terms of the number of iterations and CPU-time. The Broyden-Fletcher-Goldfarb-Shanno (BFGS) method is used as an updating formula for the approximation of the Hessian for both methods. Our numerical analysis provides strong evidence that our CG-BFGS method ...
Source
#1Mohd Rivaie (UiTM: Universiti Teknologi MARA)H-Index: 8
#2Mustafa Mamat (UMT: Universiti Malaysia Terengganu)H-Index: 16
Last. Ismail Mohd (UMT: Universiti Malaysia Terengganu)H-Index: 8
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Abstract Nonlinear conjugate gradient (CG) methods have played an important role in solving large-scale unconstrained optimization. Their wide application in many fields is due to their low memory requirements and global convergence properties. Numerous studies and modifications have been conducted recently to improve this method. In this paper, a new class of conjugate gradient coefficients ( β k ) that possess global convergence properties is presented. The global convergence result is establi...
Source
#1Mohd RivaieH-Index: 8
#2Mustafa MamatH-Index: 16
Last. Ismail MohdH-Index: 8
view all 4 authors...
Conjugate gradient (CG) methods have played an important role in solving largescale unconstrained optimization due to its low memory requirements and global convergence properties. Numerous studies and modifications have been devoted recently to improve this method. In this paper, a new modification of conjugate gradient coefficient ( k β ) with global convergence properties are presented. The global convergence result is established using exact line searches. Preliminary result shows that the p...
#1Mohammed Waziri Yusuf (UPM: Universiti Putra Malaysia)H-Index: 2
#2Leong Wah JuneH-Index: 4
Last. Malik Abu HassanH-Index: 9
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The basic requirement of Newton’s method in solving systems of nonlinear equations is, the Jacobian must be non-singular. This condition restricts to some extent the application of Newton method. In this paper we present a modification of Newton’s method for systems of nonlinear equations where the Jacobian is singular. This is made possible by approximating the Jacobian inverse into a diagonal matrix by means of variational techniques. The anticipation of our approach is to bypass the point in ...
Abstract —Clustering is one of an interesting data mining topicsthat can be applied in many fields. Recently, the problem of clusteranalysis is formulated as a problem of nonsmooth, nonconvex opti-mization, and an algorithm for solving the cluster analysis problembased on nonsmooth optimization techniques is developed. Thisoptimization problem has a number of characteristics that make itchallenging: it has many local minimum, the optimization variablescan be either continuous or categorical, and ...
#1Mustafa MamatH-Index: 4
#2Ismail MohdH-Index: 4
Last. Leong Wah JuneH-Index: 4
view all 3 authors...
In this paper we present two new numerical methods for unconstrained large-scale optimization. These methods apply update formulae, which are derived by considering different techniques of ap- proximating the objective function. Theoretical analysis is given to show the advantages of using these update formulae. It is observed that these update formulae can be employed within the framework of limited mem- ory strategy with only a modest increase in the linear algebra cost. Comparative results wi...
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