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دسترسی آزاد مقاله
1 - حل عددی مدل کسری عفونت HIV در سلولهای CD4+T
محمد رضا دوستدار طیبه دمرچلی علیرضا وحیدیدر این مقاله، مدل کسری عفونت HIV در سلولهای CD4+T بررسی قرار میگیرد. در این مدل، مشتقات کسری در مفهوم کاپوتو در نظر گرفته میشوند. در این روش، دستگاه معادلات دیفرانسیل معمولی از مرتبه کسری به یک دستگاه معادلات جبری تبدیل میگردد که میتوان آن را با استفاده از یک روش عددی م چکیده کاملدر این مقاله، مدل کسری عفونت HIV در سلولهای CD4+T بررسی قرار میگیرد. در این مدل، مشتقات کسری در مفهوم کاپوتو در نظر گرفته میشوند. در این روش، دستگاه معادلات دیفرانسیل معمولی از مرتبه کسری به یک دستگاه معادلات جبری تبدیل میگردد که میتوان آن را با استفاده از یک روش عددی مناسب حل نمود. همچنین، در بحث آنالیز خطا، کران بالای خطا ارائه شده است. کارایی و دقت روش، با استفاده از یک نمونه عددی برای برخی مشتقات صحیح و کسری بررسی و برخی مقایسه ها و نتایج گزارش شده است. در این مقاله، مدل کسری عفونت HIV در سلولهای CD4+T بررسی قرار میگیرد. در این مدل، مشتقات کسری در مفهوم کاپوتو در نظر گرفته میشوند. در این روش، دستگاه معادلات دیفرانسیل معمولی از مرتبه کسری به یک دستگاه معادلات جبری تبدیل میگردد که میتوان آن را با استفاده از یک روش عددی مناسب حل نمود. همچنین، در بحث آنالیز خطا، کران بالای خطا ارائه شده است. کارایی و دقت روش، با استفاده از یک نمونه عددی برای برخی مشتقات صحیح و کسری بررسی و برخی مقایسه ها و نتایج گزارش شده است. پرونده مقاله -
دسترسی آزاد مقاله
2 - Numerical Solution of Interval Volterra-Fredholm-Hammerstein Integral Equations via Interval Legendre Wavelets Method
N. khorrami A. Salimi Shamloo B. Parsa MoghaddamIn this paper, interval Legendre wavelet method is investigated to approximated the solution of the interval Volterra-Fredholm-Hammerstein integral equation. The shifted interval Legendre polynomials are introduced and based on interval Legendre wavelet method is define چکیده کاملIn this paper, interval Legendre wavelet method is investigated to approximated the solution of the interval Volterra-Fredholm-Hammerstein integral equation. The shifted interval Legendre polynomials are introduced and based on interval Legendre wavelet method is defined. The existence and uniqueness theorem for the interval Volterra-Fredholm-Hammerstein integral equations is proved. Some examples show the effectiveness and efficiency of the approach. پرونده مقاله -
دسترسی آزاد مقاله
3 - Injection into Orbit Optimization using Orthogonal Polynomials
Sedigheh Shahmirzaee Jeshvaghany Farshad Pazooki Alireza Basohbat NovinzaddehIn this study, the problem of determining an optimal trajectory of a nonlinear injection into orbit problem with minimum time was investigated. The method was based on orthogonalpolynomial approximation. This method consisted of reducing the optimal control problem to a چکیده کاملIn this study, the problem of determining an optimal trajectory of a nonlinear injection into orbit problem with minimum time was investigated. The method was based on orthogonalpolynomial approximation. This method consisted of reducing the optimal control problem to a system of algebraic equations by expanding the state and control vector as Chebyshev or Legendre polynomials with undetermined coefficients. The main characteristic of this technique was that it converted the differential expressions arising from the system dynamics and the performance index into some nonlinear algebraic equations, thereby greatly simplifying the problem solution. Our research effort focused on applying a Chebyshev series expansion to optimize the trajectory profile of a point-mass Satellite Launch Vehicle (SLV). This paper is divided as follows: first, the Chebyshev and Legender series expansion to optimization are introduced. Then, the flight mechanics model of the point-mass SLV is given. Next, our optimization problem is described and optimization results are presented and discussed. پرونده مقاله -
دسترسی آزاد مقاله
4 - Numerical solution of Fredholm and Volterra integral equations using the normalized Müntz−Legendre polynomials
فرشته صائمی حمیده ابراهیمی محمود شفیعیThe current research approximates the unknown function based on the normalized Müntz−Legendre polynomials (NMLPs) in conjunction with a spectral method for the solution of nonlinear Fredholm and Volterra integral equations. In this method, by using operationa چکیده کاملThe current research approximates the unknown function based on the normalized Müntz−Legendre polynomials (NMLPs) in conjunction with a spectral method for the solution of nonlinear Fredholm and Volterra integral equations. In this method, by using operational matrices, a system of algebraic equations is derived that can be readily handled through the use of the Newton scheme. The stability, error bound, and convergence analysis of the method are discussed in detail by preparing some theorems. Several illustrative examples are provided formally to show the efficiency of the proposed method. پرونده مقاله -
دسترسی آزاد مقاله
5 - Analysis of Test Day Milk Yield by Random Regression Models and Evaluation of Persistency in Iranian Dairy Cows
M. Elahi Torshizi A.A. Aslamenejad M.R. Nassiri H. Farhangfar J. Solkner M. Kovac G. Meszaros S. MalovrhVariace / covariance components of 227118 first lactaiom test-day milk yield records belonged to 31258 Iranian Holstein cows were estimated using nine random regression models. Afterwards, different measures of persistency based on estimation breeding value were evaluat چکیده کاملVariace / covariance components of 227118 first lactaiom test-day milk yield records belonged to 31258 Iranian Holstein cows were estimated using nine random regression models. Afterwards, different measures of persistency based on estimation breeding value were evaluated. Three functions were used to adjust fixed lactation curve: Ali and Schaeffer (AS), quadratic (LE3) and cubic (LE4) order of Legendre polynomial but for random effects, unequal order of Legendre polynomials (LE3, LE4, LE5 and Ali and Schaffer) functions were evaluated. Heterogeneous residual variance considered during days in milk and evaluation of models was based on eigenvalues and associated eigenvectors and residual variance. Model with Ali and Schaeffer function for fixed part and LE3 and LE4 for additive and permanent environmental effects was selected as the best model for random regression analysis in first parity dairy cows. The highest and lowest heritability were observed in the middle (0.29) and beginning (0.08) of lactation, respectively. Persistency measurement proposed by Cobuci (PSY1) (difference between estimation breeding value between 290 and 90 days) was preferential for using in further genetic evaluations for persistency in milk yield of Iranian Holstein cows. پرونده مقاله -
دسترسی آزاد مقاله
6 - Exploring the Use of Random Regression Models withLegendre Polynomials to Analyze Clutch Sizein Iranian Native Fowl
ع. عبادی تبریزی م. طهمورث‌پور ع. نجاتی جوارمیRandom regression models (RRM) have become common for the analysis of longitudinal data or repeated records on individual over time. The goal of this paper was to explore the use of random regression models with orthogonal / Legendre polynomials (RRL) to analyze new rep چکیده کاملRandom regression models (RRM) have become common for the analysis of longitudinal data or repeated records on individual over time. The goal of this paper was to explore the use of random regression models with orthogonal / Legendre polynomials (RRL) to analyze new repeated measures called clutch size (CS) as a meristic trait for Iranian native fowl. Legendre polynomial functions of increasing order 0 (no covariate) to 4 were fitted to the age at sexual maturity (ASM) and 1 to 10 to the additive genetic and permanent environmental effects. Days in production (clutch) were used as time variables. Homogeneity of residual variance through the time was assumed. Analyses were carried out within restricted maximum likelihood algorithm (REML) using WOMBAT software. Adequacy of models was checked by Bayesian information criterion (BIC). The resulted BICs suggested a model composed of the second order polynomial for ASM and 8th order polynomial for additive genetic and permanent environmental effect was the most suitable for adjusting the present records. The highest phenotypic and permanent environmental variance of CS was at the beginning of the production period. Additive genetic variance was fairly consistent during 210 and 265 days of age (d 210-d265). Estimates of heritability for CS ranged from 0.033 to 0.199 for d 161 and d 242 in the first cycle of egg production, respectively. The ratio of animal permanent environmental variance to phenotypic variance was in the range of 0.01 and 0.264. The estimated ranges for additive genetic and permanent environmental correlations were -0.18 to 0.99 and -0.5 to 0.99, respectively and were high between the adjacent ages and they tended to decrease at nonadjacent ages. پرونده مقاله -
دسترسی آزاد مقاله
7 - Genetic Analysis of Milk Yield in Iranian Holstein Cattle by the Test Day Model
ی. نادری N. امام جمعه کاشان ر. واعظ ترشیزی م. امین افشارUsing monthly test day records the genetic parameters of Iranian Holstein cattle in first lactation were studied. Data of 277400 test-day milk records from 65320 cows and 2210 sires were analyzed by an animal random regression model using restricted maximum likelihood m چکیده کاملUsing monthly test day records the genetic parameters of Iranian Holstein cattle in first lactation were studied. Data of 277400 test-day milk records from 65320 cows and 2210 sires were analyzed by an animal random regression model using restricted maximum likelihood methodology. The model included herd-test-date, interaction between year-season of calving, days in milk (linear and quadratic) and dam age (linear and quadratic) as fixed effects and random regression coefficients for additive genetic and permanent environmental effects. The average of 305 days milk yield was 9760 (±1324) kilogram. Differences of milk yield among provinces were significant (P<0.05). The average of heritability estimates of milk was 0.50. The genetic correlations between adjacent test-day records were high and decreased with increase in interval between tests. پرونده مقاله -
دسترسی آزاد مقاله
8 - Numerical Solution Two-Dimensional Volterra-Fredholm Integral Equations of the Second Kind with Block-Pulse Functions Based on Legendre Polynomials
Jafar Khazaian Nouredin Parandin Farajollah Mohammadi Yaghoobi Nasrin Karami KabirIn this paper, we present a new numerical technique based on Block-pulse functions to solve two-dimensional Volterra-Fredholm integral equations of the second kind. To produce Block-pulse functions, the orthogonal Legendre polynomials is used. Furthermore, operational m چکیده کاملIn this paper, we present a new numerical technique based on Block-pulse functions to solve two-dimensional Volterra-Fredholm integral equations of the second kind. To produce Block-pulse functions, the orthogonal Legendre polynomials is used. Furthermore, operational matrix is applied to convert two-dimensional Volterra-Fredholm integral equations to a linear algebraic system. The convergence analysis of the new method is discussed. Finally, some numerical examples are given to confirm the applicability and efficiency of the new method for solving two-dimensional Volterra-Fredholm integral equations of the second kind. پرونده مقاله
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