2021-07-24T07:54:08Z https://ajmc.aut.ac.ir/?_action=export&rf=summon&issue=313
2020-02-01 10.22060
AUT Journal of Mathematics and Computing AJMC 2020 1 1 A meshless numerical investigation based on the RBF-QR approach for elasticity problems Mostafa Abbaszadeh Mehdi Dehghan In the current research work, we present an improvement of meshless boundary element method (MBEM) based on the shape functions of radial basis functions-QR (RBF-QR) for solving the two-dimensional elasticity problems. The MBEM has benefits of the boundary integral equations (BIEs) to reduce the dimension of problem and the meshless attributes of moving least squares (MLS) approximations. Since the MLS shape functions don’t have the delta function property, applying boundary conditions is not simple. Here, we propose the MBEM using RBF-QR to increase the accuracy and efficiency of MBEM. To show the performance of the new technique, the two-dimensional elasticity problems have been selected. We solve the mentioned model on several irregular domains and report simulation results. Boundary element method RBF-QR approach Two-dimensional elasticity problems Meshless Method 2020 02 01 1 15 https://ajmc.aut.ac.ir/article_3379_ffbd2283d5745c4b85031e1eaf021000.pdf
2020-02-01 10.22060
AUT Journal of Mathematics and Computing AJMC 2020 1 1 The bimodal standard normal density and kurtosis Javad Behboodian Maryam Sharafi Zahra Sajjadnia Mazyar Zarepour  In this article, first a density by the name ”The bimodal standard normal density” is introduced and denoted by bφ(z). Then, a definition for the kurtosis of bimodal densities relative to bφ(z) is presented. Finally, to illustrate the introduced kurtosis, a few examples are provided and a real data set is studied, too. normal density mixed normal density bimodal standard normal density kurtosis of a bimodal density 2020 02 01 17 25 https://ajmc.aut.ac.ir/article_3040_cba0b169b1d9096e97113d867cacd623.pdf
2020-02-01 10.22060
AUT Journal of Mathematics and Computing AJMC 2020 1 1 (α, β)-Metrics with Killing β of Constant Length Tayebeh Tabatabaeifar Behzad Najafi The class of (α,β)-metrics is a rich and important class of Finsler metrics, which is extensively studied. Here, we study (α,β)-metrics with Killing of constant length 1-form β and find a simplified formula for their Ricci curvatures. Then, weshow that if F=α+β+b\frac{β^2}{α} is an Einstein Finsler metric, then α is an Einstein Riemann metric. Finsler metric (α,β)-metric Einstein manifold 2020 02 01 27 36 https://ajmc.aut.ac.ir/article_3038_ec3b89402c7338eacb774d68fb1a1cb0.pdf
2020-02-01 10.22060
AUT Journal of Mathematics and Computing AJMC 2020 1 1 On Sobolev spaces and density theorems on Finsler manifolds Behrooz Bidabad Alireza Shahi Here, a natural extension of Sobolev spaces is defined for a Finsler structure F and it is shown that the set of all real C∞ functions with compact support on a forward geodesically complete Finsler manifold (M, F), is dense in the extended Sobolev space H p 1 (M). As a consequence, the weak solutions u of the Dirichlet equation ∆u = f can be approximated by C∞ functions with compact support on M. Moreover, let W ⊂ M be a regular domain with the C r boundary ∂W, then the set of all real functions in C r (W) ∩ C 0 (W) is dense in H p k (W), where k ≤ r. Finally, several examples are illustrated and sharpness of the inequality k ≤ r is shown Density theorem Sobolev spaces Dirichlet problem Finsler space 2020 02 01 37 45 https://ajmc.aut.ac.ir/article_3039_ef823186580a9c859620d42c8543c999.pdf
2020-02-01 10.22060
AUT Journal of Mathematics and Computing AJMC 2020 1 1 A simple greedy approximation algorithm for the unit disk cover problem Mahdi Imanparast Seyed Naser Hashemi Given a set P of n points in the plane, the unit disk cover problem, which is known as an NP-hard problem, seeks to find the minimum number of unit disks that can cover all points of P. We present a new 4-approximation algorithm with running time O(n log n) for this problem. Our proposed algorithm uses a simple approach and is easy to understand and implement. computational geometry approximation algorithms unit disk cover problem facility location 2020 02 01 47 55 https://ajmc.aut.ac.ir/article_3044_69fd7125903ed84f45ff4a2b2a419779.pdf
2020-02-01 10.22060
AUT Journal of Mathematics and Computing AJMC 2020 1 1 The Complementary Odd Weibull Power Series Distribution: Properties and Application Mehdi Goldoust In this paper, a new four-parameters model called the complementary odd Weibull power series (COWPS) distribution is defined and its properties are explored. This new distribution exhibits several new and well-known hazard rate shapes such as increasing, decreasing, bathtub-shaped and J-shape hazard rates. Some of its mathematical properties are obtained including moments, quantiles reliability, and moment generating functions. The maximum likelihood estimation method is used to estimate the vector of parameters. A simulation study is presented to investigate the performance of the estimators. Finally, The usefulness of the model has been demonstrated by applying it to a real-life dataset. Odd Weibull distribution Power series distribution Compound distribution Maximum Likelihood Estimation 2020 02 01 57 67 https://ajmc.aut.ac.ir/article_3722_1be02552deb40e99ef41e3344ca6aa8e.pdf
2020-02-01 10.22060
AUT Journal of Mathematics and Computing AJMC 2020 1 1 A generalization of Marshall-Olkin bivariate Pareto model and its applications in shock and competing risk models Shirin Shoaee Esmaeil Khorram Statistical inference for extremes has been a subject of intensive research during the last years. In this paper, we generalize the Marshall-Olkin bivariate Pareto distribution. In this case, a new bivariate distribution is introduced by compounding the Pareto Type II and geometric distributions. This new bivariate distribution has natural interpretations and can be applied in fatal shock models or in competing risks models. We call the new proposed model Marshall-Olkin bivariate Pareto-geometric (MOBPG) distribution, and then investigate various properties of the new distribution. This model has five unknown parameters and the maximum likelihood estimators cannot be afforded in explicit structure. We suggest to use the EM algorithm to calculate the maximum likelihood estimators of the unknown parameters, and this structure is quite flexible. Also, Monte Carlo simulations are performed to investigate the effectiveness of the proposed algorithm. Finally, we analyze a real data set to investigate our purposes. Bivariate model Competing risk model Expectation-Maximization algorithm Pareto Type II distribution Shock model 2020 02 01 69 87 https://ajmc.aut.ac.ir/article_3125_8385d20bf3dcd48513f53a4a97c11981.pdf
2020-02-01 10.22060
AUT Journal of Mathematics and Computing AJMC 2020 1 1 The Validity of a Thompson’s Problem for PSL(4, 7) Behrooz Khosravi Cyrus Kalantarpour Let $pi_e(G)$ be the set of elements orders of $G$. Also let $s_n$ be the number of elements of order $n$ in $G$ and ${rm nse}(G)= lbrace s_nmid nin pi_e(G) rbrace$.In this paper we prove that if $G$ is a group such that ${rm nse}(G)= {rm nse}(rm PSL(4,7))$, $19bigvert|G|$ and $19^2nmid|G|$, then $Gcong rm PSL(4,7)$. As a consequence of this result it follows that Thompson's problem is satisfied for the simple group $rm PSL(4,7)$. Thompson’s problem Characterization Number of elements of the same order Projective special linear group Hall subgroup NSE Sporadic groups Python 2020 02 01 89 94 https://ajmc.aut.ac.ir/article_3746_c15795a34e3e77400bdbc8563d65144d.pdf
2020-02-01 10.22060
AUT Journal of Mathematics and Computing AJMC 2020 1 1 A real-time decision support system for bridge management based on the rules generalized by CART decision tree and SMO algorithms Shadi Abpeykar Mehdi Ghatee Under dynamic conditions on bridges, we need a real-time management. To this end, this paper presents a rule-based decision support system in which the necessary rules are extracted from simulation results made by Aimsun traffic micro-simulation software. Then, these rules are generalized by the aid of fuzzy rule generation algorithms. Then, they are trained by a set of supervised and the unsupervised learning algorithms to get an ability to make decision in real cases. As a pilot case study, Nasr Bridge in Tehran is simulated in Aimsun and WEKA data mining software is used to execute the learning algorithms. Based on this experiment, the accuracy of the supervised algorithms to generalize the rules is greater than 80%. In addition, CART decision tree and sequential minimal optimization (SMO) provides 100% accuracy for normal data and these algorithms are so reliable for crisis management on bridge. This means that, it is possible to use such machine learning methods to manage bridges in the real-time conditions. Intelligent Transportation Systems Knowledge Extraction Learning Algorithms Traffic Simulators Fuzzy Rule Generation Algorithm 2020 02 01 95 100 https://ajmc.aut.ac.ir/article_3043_5969ea2b069b3fd8d1e298c8a6383f87.pdf
2020-02-01 10.22060
AUT Journal of Mathematics and Computing AJMC 2020 1 1 Statistical and Fuzzy Clustering Methods and their Application to Clustering Provinces of Iraq based on Agricultural Products Israa Atiyah Seyed Mahmoud Taheri The important approaches to statistical and fuzzy clustering are reviewed and compared, and their applications to an agricultural problem based on a real-world data are investigated. The methods employed in this study includes some hierarchical clustering and non-hierarchical clustering methods and Fuzzy C-Means method. As a case study, these methods are then applied to cluster 15 provinces of Iraq based on some agricultural crops. Finally, a comparative and evaluation study of different statistical and fuzzy clustering methods is performed. The obtained results showed that, based on the Silhouette criterion and Xie-Beni index, fuzzy c-means method is the best one among all reviewed methods Hierarchical Clustering Non-Hierarchical Clustering Fuzzy C-Means Clustering 2020 02 01 101 112 https://ajmc.aut.ac.ir/article_3245_a255154ebe44780b879781a7e0ee6123.pdf
2020-02-01 10.22060
AUT Journal of Mathematics and Computing AJMC 2020 1 1 Smartphone-based System for Driver Anger Scale Estimation Using Neural Network on Continuous Wavelet Transformation Hamid Reza Eftekhari Monitoring of the driver decreases accidents by reducing the risky behaviors and causes decreases the fuel consumption by preventing aggressive behavior. But this monitoring is costly due to built-in equipment. In this study, we propose a new model to recognize driving behavior by smartphone data without any extra equipment in the vehicles which is an important added value for smartphones. This recognition process is done in this paper based on the continuous wavelet transformation on accelerometer data. Then these patterns are fed to multilayer perceptron neural network to extend the information extracted from the corresponding features. Also the magnetometer sensor is used to detect the maneuvers through the driving period. Results show the accuracy of the proposed system is near 80% for pattern recognition. Driver scale based on a standard questionnaires regarding to driver angry scale (DAS), is also estimated by the proposed multilayer perceptron neural network with 3.7% errors in the average. Risky behavior Driver monitoring smartphone Wavelet transformation Multilayer perceptron neural network 2020 02 01 113 124 https://ajmc.aut.ac.ir/article_3287_964f797962c44f02c009a4313255f902.pdf
2020-02-01 10.22060
AUT Journal of Mathematics and Computing AJMC 2020 1 1 Adopting GRASP to solve a novel model for bus timetabling problem with minimum transfer and fruitless waiting times Javad Zamani Kafshani Seyyed Ali Mirhassani Farnaz Hooshmand This paper addresses a variant of bus timetabling problem assuming that travel times changes dynamically over the planning horizon. In addition to minimizing the transfer waiting time, another objective, namely minimizing the fruitless waiting time, is introduced in this paper as a new realistic objective. First, the problem is formulated as a mixed integer linear programming model. Then, since commercial solvers become inefficient to solve moderate and large sized instances of the problem (due to the NP-hardness), a GRASP heuristic algorithm is developed. Computational experiments over a variety of random instances verify the performance of the proposed method. Bus timetabling Dynamic travel time Transfer waiting time Fruitless waiting time GRASP 2020 02 01 125 134 https://ajmc.aut.ac.ir/article_3323_85cc256ebddca4a51b227d38698683da.pdf