eng
Islamic Azad University, Central tehran Branch
International Journal of Mathematical Modelling & Computations
2228-6225
2228-6233
2014-03-21
4
4 (FALL)
299
307
521869
ANALYSIS OF RENEWAL INPUT STATE DEPENDENT VACATION QUEUE WITH $N$-POLICY
Vijaya Laxmi Pikkala
1
Suchitra Vepada
2
Andhra University, Visakhapatnam India
Andhra University, Visakhapatnam India
This paper analyzes renewal input state dependent queue with $N$- policy wherein the server takes exactly one vacation. Using the supplementary variable technique and recursive method, we derive the steady state system length distributions at various epochs. Various performance measures has been presented. Finally, some numerical computations in the form of graphs are presented to show the parameter effect on various performance measures.
http://ijm2c.iauctb.ac.ir/article_521869_f3aa2e39f9752bab4ffc7ea08b1aa816.pdf
Finite buffer
State dependent
Single vacation
$N$-policy
Supplementary variable
eng
Islamic Azad University, Central tehran Branch
International Journal of Mathematical Modelling & Computations
2228-6225
2228-6233
2014-03-21
4
4 (FALL)
309
329
521870
AN INTELLIGENT FAULT DIAGNOSIS APPROACH FOR GEARS AND BEARINGS BASED ON WAVELET TRANSFORM AS A PREPROCESSOR AND ARTIFICIAL NEURAL NETWORKS
Mahmuod Akbari
1
Hadi Homaei
2
Mohammad Heidari
3
Shahrekord University Iran, Islamic Republic of
Shahrekord University Iran, Islamic Republic of
Islamic Azad University Iran, Islamic Republic of
In this paper, a fault diagnosis system based on discrete wavelet transform (DWT) and artificial neural networks (ANNs) is designed to diagnose different types of fault in gears and bearings. DWT is an advanced signal-processing technique for fault detection and identification. Five features of wavelet transform RMS, crest factor, kurtosis, standard deviation and skewness of discrete wavelet coefficients of normalized vibration signals has been selected. These features are considered as the feature vector for training purpose of the ANN. A wavelet selection criteria, Maximum Energy to Shannon Entropy ratio, is used to select an appropriate mother wavelet and discrete level, for feature extraction. To ameliorate the algorithm, various ANNs were exploited to optimize the algorithm so as to determine the best values for ‘‘number of neurons in hidden layer” resulted in a high-speed, meticulous three-layer ANN with a small-sized structure. The diagnosis success rate of this ANN was 100% for experimental data set. Some experimental set of data has been used to verify the effectiveness and accuracy of the proposed method. To develop this method in general fault diagnosis application, three different examples were investigated in cement industry. In first example a MLP network with well-formed and optimized structure (20:15:7) and remarkable accuracy was presented providing the capability to identify different faults of gears and bearings. In second example a neural network with optimized structure (20:15:4) was presented to identify different faults of bearings and in third example an optimized network (20:15:3) was presented to diagnose different faults of gears. The performance of the neural networks in learning, classifying and general fault diagnosis were found encouraging and can be concluded that neural networks have high potential in condition monitoring of the gears and bearings with various faults.
http://ijm2c.iauctb.ac.ir/article_521870_995970f0c2fe76e90de2cdfd65eee46d.pdf
Discrete wavelet transform
artificial neural network
Fault diagnosis
Vibration analysis
eng
Islamic Azad University, Central tehran Branch
International Journal of Mathematical Modelling & Computations
2228-6225
2228-6233
2014-03-21
4
4 (FALL)
331
339
521871
USING PG ELEMENTS FOR SOLVING FREDHOLM INTEGRO-DIFFERENTIAL EQUATIONS
Majid Karami
1
South Tehran Branch, Islamic Azad university Iran, Islamic Republic of
In this paper, we use Petrov-Galerkin elements such as continuous and discontinuous Lagrange-type k-0 elements and Hermite-type 3-1 elements to find an approximate solution for linear Fredholm integro-differential equations on $[0,1]$. Also we show the efficiency of this method by some numerical examples
http://ijm2c.iauctb.ac.ir/article_521871_5089b868603fc0fa47735683d227a105.pdf
integro-differential equations
Petrov-Galerkinmethod
Regular pair
Trial space
Test space
eng
Islamic Azad University, Central tehran Branch
International Journal of Mathematical Modelling & Computations
2228-6225
2228-6233
2014-03-21
4
4 (FALL)
341
355
521872
RESOLUTION METHOD FOR MIXED INTEGER LINEAR MULTIPLICATIVE-LINEAR BILEVEL PROBLEMS BASED ON DECOMPOSITION TECHNIQUE
Habibe Sadeghi
1
Leila Karimi
2
Iran, Islamic Republic of
In this paper, we propose an algorithm base on decomposition technique for solvingthe mixed integer linear multiplicative-linear bilevel problems. In actuality, this al-gorithm is an application of the algorithm given by G. K. Saharidis et al for casethat the rst level objective function is linear multiplicative. We use properties ofquasi-concave of bilevel programming problems and decompose the initial probleminto two subproblems to names RMP and SP. The lower and upper bound providedfrom the RMP and SP are updated in each iteration. The algorithm converges whenthe dierence between the upper and lower bound is less than an arbitrary tolerance.Finally, we give some numerical examples are presented in order to show the eciencyof algorithm.
http://ijm2c.iauctb.ac.ir/article_521872_35c15e5bd53756c0e5bdf5893dc345ff.pdf
Bilevel programming
Mixed integer linear programming
Benders decomposition
Multiplicative programming
eng
Islamic Azad University, Central tehran Branch
International Journal of Mathematical Modelling & Computations
2228-6225
2228-6233
2014-03-21
4
4 (FALL)
357
364
521873
EXISTENCE OF FIXED POINTS OF CERTAIN CLASSES OF NONLINEAR MAPPINGS
odwin Amechi Okeke
1
Johnson O Olaleru
2
Department of Mathematics, University of Lagos, Nigeria Nigeria Lecturer,Department of Mathematics,University of Lagos,Nigeria.
Department of Mathematics, University of Lagos, Nigeria. Professor,Department of Mathematics,University of Lagos,Nigeria.
In this study, we introduce the classes of $phi$-strongly pseudocontractive mappings in the intermediate sense and generalized $Phi$-pseudocontractive mappings in the intermediate sense and prove the existence of fixed points for those maps. The results generalise the results of several authors in literature including Xiang [Chang He Xiang, Fixed point theorem for generalized $Phi$-pseudocontractive mappings, Nonlinear Analysis 70 (2009) 2277-2279].
http://ijm2c.iauctb.ac.ir/article_521873_1adc1d9256741dc0ad38e2d2cfc3bd8b.pdf
generalized $Phi$-pseudocontractive mappings in the intermediate sense
Banach spaces
fixed point
eng
Islamic Azad University, Central tehran Branch
International Journal of Mathematical Modelling & Computations
2228-6225
2228-6233
2014-03-21
4
4 (FALL)
365
376
521874
TENSION TRIGONOMETRIC SPLINES INTERPOLATION METHOD FOR SOLVING A LINEAR BOUNDARY VALUE PROBLEM
Omar El Khayyari
1
Abdellah Lamnii
2
Jaoud Dabounou
3
Faculty of Science and Technology University Hassan first, Settat Morocco Morocco
Faculty of Science and Technology, University Hassan first, Settat Morocco
Faculty of Science and Technology, University Hassan first, Settat Morocco
By using the trigonometric uniform splines of order 3 with a real tension factor, a numericalmethod is developed for solving a linear second order boundary value problems (2VBP) withDirichlet, Neumann and Cauchy types boundary conditions. The moment at the knots isapproximated by central finite-difference method. The order of convergence of the methodand the theory is illustrated by solving test examples. Experimental results demonstrate thatour method is more effective for the problems where the exact solution is trigonometric orhyperbolic.
http://ijm2c.iauctb.ac.ir/article_521874_baa4d7d431588203cd3cb242c204ff77.pdf
Trigonometric B-splines
Tension factor
Boundary value problems
eng
Islamic Azad University, Central tehran Branch
International Journal of Mathematical Modelling & Computations
2228-6225
2228-6233
2014-03-21
4
4 (FALL)
377
387
521875
CAS WAVELET METHOD FOR THE NUMERICAL SOLUTION OF BOUNDARY INTEGRAL EQUATIONS WITH LOGARITHMIC SINGULAR KERNELS
Hojatollah Adibi
1
M. Shamooshaky
2
Pouria Assar
3
Department of Mathematics, amirkabir University,Iran Department of mathematics, IAU,TCB Iran, Islamic Republic of
Amirkabir University of Technology
In this paper, we present a computational method for solving boundary integral equations with loga-rithmic singular kernels which occur as reformulations of a boundary value problem for the Laplacian equation. Themethod is based on the use of the Galerkin method with CAS wavelets constructed on the unit interval as basis.This approach utilizes the non-uniform Gauss-Legendre quadrature rule for approximating logarithm-like singularintegrals and so reduces the solution of boundary integral equations to the solution of linear systems of algebraicequations. The properties of CAS wavelets are used to make the wavelet coe±cient matrices sparse, which eventuallyleads to the sparsity of the coe±cient matrix of the obtained system. Finally, the validity and e±ciency of the newtechnique are demonstrated through a numerical example.
http://ijm2c.iauctb.ac.ir/article_521875_972f715926840cc1696e1b75ff5cc5ee.pdf
Boundary integral equation
Logarithmic singular kernel
Galerkin Method
CAS wavelet
Laplacian equation
sparse matrix
eng
Islamic Azad University, Central tehran Branch
International Journal of Mathematical Modelling & Computations
2228-6225
2228-6233
2014-03-21
4
4 (FALL)
389
400
521876
SPOT PATTERNS IN GRAY SCOTT MODEL WITH APPLICATION TO EPIDEMIC CONTROL
Muhammad Abdullahi Yau
1
M. U. Adehi
2
Muktari Garba
3
Department of Mathematical Sciences, Nasarawa State University Keffi, Nigeria; Nigeria
Department of Statistics, Waziri Umaru Federal Polytechnic Birnin-Kebbi, Nigeria. Nigeria
In this work, we analyse a pair of two-dimensional coupled reaction-diusion equations known as the Gray-Scott model, in which spot patterns have been observed. We focus on stationary patterns, and begin by deriving the asymptotic scaling of the parameters and variables necessary for the analysis of these patterns. A complete bifurcation study of these solutions is presented. The main mathematical techniques employed in this analysis of the stationary patterns is the Turing instability theory. This paper addresses the question of how popula-tion diusion aects the formation of the spatial patterns in the Gray-Scott model by Turing mechanisms. In particular, we present a theoretical analysis of results of the numerical simulations in two dimensions. Moreover, there is a critical value for the system within the linear regime. Below the critical value the spatial patterns are impermanent, whereas above it stationary spot patterns can exist over time. We have observed the formation of spatial patterns during the evolution, which are sparsely isolated ordered spot patterns that emerge in thespace. In this research we focuse on three areas: rst, the biology; second, the mathematics and third, the application. We use these spatial patterns to understand the nature of disease spread and that means to understand the mechanism of interaction of the populations. There remains uncertainty in the mechanisms surrounding the genesis of how epidemics spread in their spatial enveronment. The role of mathematical modelling in understanding the spreadand control of epidemics can never be over emphised.
http://ijm2c.iauctb.ac.ir/article_521876_bebbadae6dabca89403cbeee7e82f048.pdf
Pattern Formation
Turing instability
Gray-Scott model
stability analysis