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دسترسی آزاد مقاله
1 - Transverse perturbation on three-dimensional ion acoustic waves in electron–positron–ion plasma with high-energy tail electron and positron distribution
M. Shahmansouri E. AstarakiAbstractThe basic features of nonlinear ion acoustic (IA) waves are theoretically studied in a superthermal electron–positron–ion (e–p–i) plasma with weakly transverse perturbation. A three-dimensional Kadomtsev–Petviashvili (KP) equation governing evolution of weakly n چکیده کاملAbstractThe basic features of nonlinear ion acoustic (IA) waves are theoretically studied in a superthermal electron–positron–ion (e–p–i) plasma with weakly transverse perturbation. A three-dimensional Kadomtsev–Petviashvili (KP) equation governing evolution of weakly nonlinear IA waves is derived by means of a reductive perturbation method. The energy integral equation is used to study the existence domain of the localized structures. It is found that deviation from thermodynamics equilibrium increases the existence domain of solitary solution and also makes the IA solitary structure more spiky. The ion concentration has an important effect on the existence domain of solitary solution, as for low ion density the primitive domain reduces significantly. پرونده مقاله -
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2 - روش جدید تفاضلات متناهی ضمنی برای حل معادلات دیفرانسیل جزئی مرتبه کسری زمان- مکان دوطرفه
حمید رضا خدابنده لو الیاس شیوانیان شعبان مصطفائیمعادلات دیفرانسیل جزئی مرتبه کسری تعمیمی از معادلات دیفرانسیل جزئی کلاسیک می‌شد. تاریخ حساب دیفرانسیل کسری، تقریبا هم قدمت حساب دیفرانسیل مرتبه‌ی صحیح است، حساب دیفرانسیل و انتگرال کسری زمینه‌ای از مطالعات ریاضی است که از تعاریف اولیه، از عملگرهای مشتق و انتگرال حساب دی چکیده کاملمعادلات دیفرانسیل جزئی مرتبه کسری تعمیمی از معادلات دیفرانسیل جزئی کلاسیک می‌شد. تاریخ حساب دیفرانسیل کسری، تقریبا هم قدمت حساب دیفرانسیل مرتبه‌ی صحیح است، حساب دیفرانسیل و انتگرال کسری زمینه‌ای از مطالعات ریاضی است که از تعاریف اولیه، از عملگرهای مشتق و انتگرال حساب دیفرانسیل و انتگرال معمولی به وجود آمده است. هرچند بخاطر فقدان سابقه ی کاربردی، حساب دیفرانسیل کسری پیشرفت کمی داشته است .بعلاوه این مدلها در موضوعاتی مثل جریانات سیال و... کاربرد دارد. در این مقاله، ما بعضی از روش‌های کاربردی را برای حل معادلات دیفرانسیل جزئی کسری زمانی با مقادیر اولیه و مرزی با ضرایب متغییر روی دامنه‌ی متناهی مورد استفاده قرار داده‌ایم. سازگاری، پایداری و در نتیجه همگرایی روش را اثبات کرده، و نشان داده ایم که روش کرانک - نیکلسون کسری با تقریب گرانوالد انتقال یافته بدون شرط پایدار است. این پژوهش از هردوجنبه‌ی تئوری و عددی حائز اهمیت می باشد، که در اینجا ما با ساختمان و تحلیل همگرایی الگوهای گسسته سازی سروکار داریم. و همچنین نتایج عددی ارائه و از نظر مرتبه همگرایی با جواب تحلیلی دقیق مقایسه گردیده است. پرونده مقاله -
دسترسی آزاد مقاله
3 - An Explicit Single-step Method for Numerical Solution of Optimal Control Problems
M. Ebadi I. Malihmaleki AR. Haghigi A. EbadianIn this research we used forward-backward sweep method(FBSM) in order to solve optimal control problems. In this paper, one hybrid method based on ERK method of order 4 and 5 are proposed for the numerical approximation of the OCP. The convergence of the new method has چکیده کاملIn this research we used forward-backward sweep method(FBSM) in order to solve optimal control problems. In this paper, one hybrid method based on ERK method of order 4 and 5 are proposed for the numerical approximation of the OCP. The convergence of the new method has been proved .This method indicate more accurate numerical results compared with those of ERK method of order 4 and 5 for solving OCP. پرونده مقاله -
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4 - On Optimal Quadrature Rule for Solving Fuzzy Fredholm Integral Equations
R. Ezzati M. M. SadatrasouIn this paper, we present an efficient iterative procedure based on optimal fuzzy quadrature formula to solve fuzzy integral equations. Error estimation and the numerical stability analysis with respect to the choice of the first iteration are given. Some illustrative a چکیده کاملIn this paper, we present an efficient iterative procedure based on optimal fuzzy quadrature formula to solve fuzzy integral equations. Error estimation and the numerical stability analysis with respect to the choice of the first iteration are given. Some illustrative and comparative numerical experiments confirm the optimization of the successive ‎method.‎ پرونده مقاله -
دسترسی آزاد مقاله
5 - Design an Adaptive Sliding Mode Controller for a Class of Underactuated Systems
Hossein Moeinkhah Mohammad Ahmadi BalootakiThe majority of underactuated systems are nonholonomic, due to non-integrable differential constraints. Therefore, controlling an underactuated system is considered as a challenging problem. In this study, an adaptive controller based on super-twisting sliding mode cont چکیده کاملThe majority of underactuated systems are nonholonomic, due to non-integrable differential constraints. Therefore, controlling an underactuated system is considered as a challenging problem. In this study, an adaptive controller based on super-twisting sliding mode controller is proposed for a class of robust underactuated systems subjected to uncertainties and external disturbances. The adaptive compensator was designed so that there would be no need to the upper bound of the external disturbance. The controller parameters of adaptive sliding mode control are tuned based on a multi-objective non-dominated sorting of genetic optimization algorithm. The results of simulation and the demonstration of the effectiveness and applicability of the proposed scheme are presented. پرونده مقاله -
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6 - On the Analysis of FGM Beams: FEM with Innovative Element
M Zakeri A Modarakar Haghighi R AttarnejadThis paper aims at presenting a new efficient element for free vibration and instability analysis of Axially Functionally Graded Materials (FGMs) non-prismatic beams using Finite Element Method (FEM). Using concept of Basic Displacement Functions (BDFs), two- node eleme چکیده کاملThis paper aims at presenting a new efficient element for free vibration and instability analysis of Axially Functionally Graded Materials (FGMs) non-prismatic beams using Finite Element Method (FEM). Using concept of Basic Displacement Functions (BDFs), two- node element extends to three-node element for obtaining much more exact results using FEM. First, BDFs are introduced and computed using energy method such as unit-dummy load method. Afterward, new efficient shape functions are developed in terms of BDFs during the procedure based on the mechanical behavior of the element in which presented shape functions benefit generality and accuracy from stiffness and force method, respectively. Finally, deriving structural matrices of the beam with respect to new shape functions; free vibration and instability analysis of the FGM beam are studied using finite element method for all types of AFGM beams and the convergence of FEM has been studied. The results from both free vibration and instability analysis are in perfect agreement with those of previously published. پرونده مقاله -
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7 - Crack Influences on the Static and Dynamic Characteristic of a Micro-Beam Subjected to Electro Statically Loading
A.R Shahani G Rezazadeh A RahmaniIn the present work the pull-in voltage of a micro cracked cantilever beam subjected to nonlinear electrostatic pressure was studied. Two mathematical models were employed for modeling the problem: a lumped mass model and a classical beam model. The effect of crack in t چکیده کاملIn the present work the pull-in voltage of a micro cracked cantilever beam subjected to nonlinear electrostatic pressure was studied. Two mathematical models were employed for modeling the problem: a lumped mass model and a classical beam model. The effect of crack in the lumped mass model is the reduction of the effective stiffness of the beam and in the beam model; the crack is modeled as a massless rotational spring the compliance of which is related to the crack depth. Using these two models the pull-in voltage is extracted in the static and dynamic cases. Stability analysis is also accomplished. It has been observed that the pull-in voltage decreases as the crack depth increases and also when the crack approaches the clamped support of the beam. The finding of this research can further be used as a non-destructive test procedure for detecting cracks in micro-beams. پرونده مقاله -
دسترسی آزاد مقاله
8 - Crack analysis related to the stability of gravity and concrete dams using CADAM software (Case study: Dez regulatory dam)
علی بهشتی حسن کیامنشThe present study investigates the stress and crack analysis in weighted concrete dams under constant acceleration resulting from earthquakes in the horizontal direction and induced earthquakes generated by the dam reservoir. This analysis was performed using CADAM soft چکیده کاملThe present study investigates the stress and crack analysis in weighted concrete dams under constant acceleration resulting from earthquakes in the horizontal direction and induced earthquakes generated by the dam reservoir. This analysis was performed using CADAM software. The main purpose of stress calculations is to determine the amount of tensile length of the gap that is created by the inertial forces in the dam and the effect of these stresses on the stability of the concrete dam. CADAM software was developed in 2003 at the University of Montreal to analyze concrete dams in a variety of situations. In this paper, the gap and its effect on the stability of the concrete weight barrier with a maximum earthquake of 0.28 g were analyzed and the results were analyzed separately in each executive joint. In all joints, the minimum coefficient of safety against stability (at least 1.3) was obtained. Looking at the tables of results, it can be concluded that the stability of the regulating dam is suitable for acceleration of horizontal earthquake equal to 0.28 g. They are acceptable in earthquake and normal conditions. پرونده مقاله -
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9 - کاربرد تئوری فازی در تحلیل پایداری شیروانی ها(با نگرشی به زمین لغزش محمد آباد جیرفت)
مهدی محمدی حسین توکلی حمید شجاعی -
دسترسی آزاد مقاله
10 - Studying the Effect of Horizontal Drains on Stability of Heterogeneous and Homogeneous Earth Dams during Rapid Drawdown Condition
Alireza Hajiani Boushehrian Azadeh Rezaee Arash VafamandOne of the main concerns to design earth dam is the stability of the upstream slope of the earth dam in phase of rapid drawdown. Confined pore water pressure reduces the effective stress in this mode, so possibility of the instability and slippage will be increased. The چکیده کاملOne of the main concerns to design earth dam is the stability of the upstream slope of the earth dam in phase of rapid drawdown. Confined pore water pressure reduces the effective stress in this mode, so possibility of the instability and slippage will be increased. The main goal of this research is to investigate changes in the pore water pressure by using horizontal drains in upstream slope of the earth dams and the improvement in case of the factor of safety. In this study, firstly, the homogeneous and heterogeneous modes of the earth dam are considered and then rapid drawdown mode are modeled in two upstream slope modes without the horizontal drain and with the upstream slope including up to seven horizontal drains. These two modes are modeled by using GEOSTUDIO software. According to the obtained results, improvement by horizontal drains leads to increase in dissipation of pore water pressure and also increase the stability of the safety factor of the upstream slope up to 24% for homogeneous dams and 17% for heterogeneous dams. Practical equations were also presented to show the relation between the numbers of horizontal drains, the factor of safety and the pore water pressure. In order to study the influence of the horizontal drains on the upstream slope of the earth dams during the rapid drawdown condition, Molasadra earth dam geometry is used both in the modes of homogenous and heterogeneous dam. Molasadra dam and power station is located in about 13 kilometers of southwest of Sadeh county, around of Eghlid town in the north of Fars province in Iran. پرونده مقاله -
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11 - پایداری عملکرد دانه برخی ارقام گندم نان در مناطق سرد و معتدل ایران
علیرضا تاری نژادبررسی عملکرد ژنوتیپ ها به علت وجود اثرمتقابل ژنوتیپ×محیط، معمولاً در دامنه وسیعی از شرایط محیطی مورد آزمایش قرار می گیرد تا اطلاعات حاصله بتواند کارایی مربوط به گزینش و معرفی ارقام را افزایش دهد. به منظور بررسی پایداری عملکرد دانه برخی ارقام معرفی شده در طی سال ها چکیده کاملبررسی عملکرد ژنوتیپ ها به علت وجود اثرمتقابل ژنوتیپ×محیط، معمولاً در دامنه وسیعی از شرایط محیطی مورد آزمایش قرار می گیرد تا اطلاعات حاصله بتواند کارایی مربوط به گزینش و معرفی ارقام را افزایش دهد. به منظور بررسی پایداری عملکرد دانه برخی ارقام معرفی شده در طی سال های گذشته به مناطق سرد و معتدل کشور، بیست رقم گندم نان در قالب طرح بلوک های کامل تصادفی با سه تکرار در ایستگاه تحقیقات کشاورزی دانشگاه آزاد اسلامی واحد تبریز، از پاییز 1388 به مدت چهار سال زراعی کشت گردید. با توجه به معنی دار بودن اثرمتقابل ژنوتیپ در محیط، تجزیه پایداری با تمام روش های ممکن انجام گردید تا پایدارترین و پرمحصول ترین ارقام شناسایی گردند. نتایج حاصل از انجام روش های مختلف تجزیه پایداری نشان داد روش های تک متغیره تجزیه پایداری غیرپارامتری ارقام با عملکرد پایین، روش های امی و GGE بای پلات، ارقام با پتانسیل عملکرد متوسط به بالا و گزینش همزمان ارقام با عملکرد بسیار بالا را به عنـوان ژنوتیپ های پایدار معرفی می نماید. بر اساس اکثر روش های پارامتر پایداری، رقم بهار با تیپ رشد بهاره معرفی شده در سال 1387، مهدوی با تیپ رشد فاکلداتیو آزادسازی شده در سال 1374 و در مرتبه بعدی رقم آزادی با تیپ رشد زمستانه معرفی شده در سال 1358به ترتیب با میانگین عملکرد 27/7، 13/7 و 88/6 تن در هکتار پایدارترین و پرمحصول ترین رقم در بین ارقام محسوب شدند و می توان این ارقام را به عنوان یکی از والدین تلاقی ها، در برنامه های به نژادی جهت تولید ارقام پرمحصول و پایدار استفاده نمود. پرونده مقاله -
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12 - Stability of Robust Lyapunov Based Control of Flexible-Joint Robots Using Voltage Control Strategy Revisited
Ali DeylamiMany advanced robot applications such as assembly and manufacturing require mechanical interaction of the robot manipulator with the environment. Any back-stepping based control strategy proposed for position control of electrical flexible joint robots requires a conver چکیده کاملMany advanced robot applications such as assembly and manufacturing require mechanical interaction of the robot manipulator with the environment. Any back-stepping based control strategy proposed for position control of electrical flexible joint robots requires a convergence of internal signals to its desired value called a fictitious control signal. This problem is complicated and time-consuming, whereas a 5th-order nonlinear differential equation describes each joint of the robot. The best idea is to focus on the convergence of main signals while the other signals in the system remain bounded. With this in mind, this paper present a robust Lyapunov-based controller for the flexible joint electrically driven robot (FJER) considering input nonlinearities associated with actuator constraints. It also finds uncertainties associated with robot dynamics. The proposed approach is based on a third-order model instead of a fifth-order model of the robotic system. The stability is guaranteed in the presence of both structured and unstructured uncertainties. The actuator/link position errors asymptotically converge to zero while the other signals are bounded. Simulation results on a 2-DOF electrical robot manipulator effectively verify the efficiency of the proposed strategy. پرونده مقاله -
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13 - Task-space Control of Robots Using an Adaptive Taylor Series Uncertainty Estimator Revisited
Masoud ShahhosseiniThis paper presents an improved version of the article “task-space control of robots uses an adaptiveTaylor series uncertainty estimator” by designing a more general framework for dealing withactuator saturation. There are four important issues about the afo چکیده کاملThis paper presents an improved version of the article “task-space control of robots uses an adaptiveTaylor series uncertainty estimator” by designing a more general framework for dealing withactuator saturation. There are four important issues about the aforementioned article. Firstly, thesaturated and unsaturated regions have been discussed separately in that article, while this paperpresents a unified approach for stability analysis. Secondly, the linear parameterization of unknownmulti-variable vector-valued nonlinearities represented in the aforementioned article is not true.Consequently, it will affect the stability analysis significantly and the obtained results are doubtful.Thirdly, although the tracking error is bounded in the saturated area, it may be unacceptable due toundesirable performance. Thus, performance evaluation is needed to verify the satisfactoryoperation of the control system. However, in the aforementioned article, performance evaluationhas not been presented. Fourthly, the aforementioned paper applies the Taylor series as a universalapproximator without verifying the conditions of the universal approximation theorem. This paperproves that the Taylor series can satisfy the conditions of this theorem. All these four importantissues are addressed in this paper and a modified version of the aforementioned article is presented. پرونده مقاله -
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14 - Stability analysis of jointed rock slopes using key block method (Case study: Gas Flare site in 6, 7 and 8 phases of South Pars Gas Complex)
Mohammad Azarafza Ali Reza Yarahmadi Bafghi Ebrahim Asghari-Kaljahi Gholamreza Bahmannia Mohammadreza Moshrefy-farStability analysis and calculation of safety factor of slopes especially jointed rock slopes, the most important noticeable issue for stability analysis of slopes. Numerical modeling of soil and rock slope stability analysis most widely used in engineering geology. In t چکیده کاملStability analysis and calculation of safety factor of slopes especially jointed rock slopes, the most important noticeable issue for stability analysis of slopes. Numerical modeling of soil and rock slope stability analysis most widely used in engineering geology. In this study, for analyze the complex slope used geotechnical modeling. Geotechnical modeling was separated into two parts, the first intended for geometrical modeling and the second for two-dimensional mechanical modeling. This model based on the proposed algorithm developed in MATHEMATICA software. Modeling on the complex slope in the Gas Flare site has been implemented. Due to the location of the Gas Flare site in Assalouyeh anticline, slopes are in Mishan and Aghajari marl formations. Because of the STR - 01 slope complicated conditions and discontinuity system, for stability analysis have been selected. The main body of this slope is divided into two distinct parts with different mechanical properties. The STR - 01-1 Section due to the high fragmentation, discontinuity system and low spacing, in pseudo-soil conditions can be found on site. In this section, the overall structure of the body is still preserved, but the rock body is so badly crushed. For this reason, the rock mass as soil condition is considered and analysed. The STR - 01-2 section as a STR - 01-1 section is not crushed. Then for the STR -01-2 section, structural analysis under jointed rock mass condition. The proposed algorithm used for this analysis, is based on the appropriate assumptions and the ability to accurately. Finally for geotechnical model control, results of the proposed method with the results of Basic key group method and numerical modeling with distinct element method by UDEC and for pseudo-soil conditions with finite difference method by Flac/slope are calculated and compared. The results of the proposed method are in good agreement with the results of the numerical methods. پرونده مقاله -
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15 - Stability analysis and numerical modelling of toppling failure of discontinuous rock slope (A Case study)
Shahrzad Nikoobakht Mohammad AzarafzaOn the north-side of Phase 7 gas flare site located in South Pars Gas Complex (SPGC), Assalouyeh, Iran has a discontinuous rock slope that due to tectonic activity has been vertical mode folded. Also, the coastal climate caused to weathering of mass and occurring toppli چکیده کاملOn the north-side of Phase 7 gas flare site located in South Pars Gas Complex (SPGC), Assalouyeh, Iran has a discontinuous rock slope that due to tectonic activity has been vertical mode folded. Also, the coastal climate caused to weathering of mass and occurring toppling failure in this slope. This instability causes some problems in accessing the flare site. So, this slope need to stability analysis and stabilization. In order to stability analysis of this discontinuous rock slope, utilized the distinct elements method (DEM). The modelling process of toppling failures in UDEC is divided to geometrical and mechanical modelling. The result of modelling has good agreement with the toppling failures definition and process. پرونده مقاله -
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16 - New Applications on Linguistic Mathematical Structures and Stability Analysis of Linguistic Fuzzy Models
Jafar Tavoosi Sajjad RahmatiIn this paper some algebraic structures for linguistic fuzzy models are defined for the first time. By definition linguistic fuzzy norm, stability of these systems can be considered. Two methods (normed-based & graphical-based) for stability analysis of linguist fuzzy s چکیده کاملIn this paper some algebraic structures for linguistic fuzzy models are defined for the first time. By definition linguistic fuzzy norm, stability of these systems can be considered. Two methods (normed-based & graphical-based) for stability analysis of linguist fuzzy systems will be presented. At the follow a new simple method for linguistic fuzzy numbers calculations is defined. At the end two simple (stable and unstable) systems are modeled by linguistic fuzzy logic then stability of them by both methods are checked. In this paper some algebraic structures for linguistic fuzzy models are defined for the first time. By definition linguistic fuzzy norm, stability of these systems can be considered. Two methods (normed-based & graphical-based) for stability analysis of linguist fuzzy systems will be presented. At the follow a new simple method for linguistic fuzzy numbers calculations is defined. At the end two simple (stable and unstable) systems are modeled by linguistic fuzzy logic then stability of them by both methods are checked. پرونده مقاله -
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17 - Dynamics of Food Chain Model: Role of Alternative Resource for Top Predator
ANUJ KUMAR MANJU AGARWALIn this paper, effect of alternative resource for top predator in food chain model with holling type III functional response is seen . Proposed model is demonstrated in respect of analytical as well numerical results. Bifurcation study with the variation of alternative چکیده کاملIn this paper, effect of alternative resource for top predator in food chain model with holling type III functional response is seen . Proposed model is demonstrated in respect of analytical as well numerical results. Bifurcation study with the variation of alternative resource and half saturation constants are done numerically. Simulation results shows that suitable alternative resource has the capability to prevent top predator extinction. پرونده مقاله -
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18 - Mathematical Model of Herpes Simplex Virus – II (HSV-II) with Global Stability Analysis
Eshetu Gurmu Boka Bole Purnachandra KoyaIn this paper, a nonlinear deterministic mathematical model of ordinary differential equations has been formulated to describe the transmission dynamics of HSV-II. The well-posedness of the formulated model equations was proved and the equilibrium points of the model ha چکیده کاملIn this paper, a nonlinear deterministic mathematical model of ordinary differential equations has been formulated to describe the transmission dynamics of HSV-II. The well-posedness of the formulated model equations was proved and the equilibrium points of the model have been identified. In addition, the basic reproduction number that governs the disease transmission was obtained from the largest eigenvalue of the next-generation matrix. Both local and global stability of the disease-free equilibrium and endemic equilibrium point of the model equation was established using the basic reproduction number. The results show that, if the basic reproduction is less than one then the solution converges to the disease-free steady-state and the disease-free equilibrium is locally asymptotically stable. On the other hand, if the basic reproduction number is greater than one the solution converges to endemic equilibrium point and the endemic equilibrium is locally asymptotically stable. Also, sensitivity analysis of the model equation was performed on the key parameters to find out their relative significance and potential impact on the transmission dynamics of HSV-II. Finally, numerical simulations of the model equations are carried out using the software DE Discover 2.6.4 and MATLAB R2015b with ODE45 solver. The results of simulation show that treatment minimizes the risk of HSV-II transmission from the community and the stability of disease-free equilibrium is achievable when R0<1. پرونده مقاله -
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19 - Mathematical Modeling of COVID-19 Pandemic with Treatment
Abayneh BezabihIn this paper, mathematical model of COVID-19 Pandemic is discussed. The positivity, boundedness, and existence of the solutions of the model equations are proved. The Disease-free & endemic equilibrium points are identified. Stability Analysis of the model is done with چکیده کاملIn this paper, mathematical model of COVID-19 Pandemic is discussed. The positivity, boundedness, and existence of the solutions of the model equations are proved. The Disease-free & endemic equilibrium points are identified. Stability Analysis of the model is done with the concept of Next generation matrix. we investigated that DFEP of the model E_0 is locally asymptotically stable if α≤β+δ+μ & unstable if α>β+δ+μ . It is shown that if reproduction number is less than one, then COVID-19 cases will be reduced in the community. However, if reproduction number is greater than one, then covid-19 continue to persist in the Community. Lastly, numerical simulations are done with DEDiscover 2.6.4. software. It is observed that with Constant treatment, increase or decrease contact rate among persons leads great variation on the basic reproduction number which is directly implies that infection rate plays a vital role on decline or persistence of COVID-19 pandemic. پرونده مقاله -
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20 - Stability Analysis of Fractional Order Mathematical Model of Leukemia
Lahoucine BoujallalIn this paper, we propose a fractional order model of leukemia in terms of a system of ordinary differential equations with the Caputo derivative that provides convenience for initial conditions of the differential equations. Firstly, we prove the global existence, posi چکیده کاملIn this paper, we propose a fractional order model of leukemia in terms of a system of ordinary differential equations with the Caputo derivative that provides convenience for initial conditions of the differential equations. Firstly, we prove the global existence, positivity, and boundedness of solutions. The local stability properties of the equilibrium are obtained by using fractional Routh-Hurwitz stability criterion. Furthermore, a suitable Lyapunov functions are constructed to prove the global stability of equilibrium. Finally, numerical simulation of the model are presented to illustrate our theoretical results for different choices of fractional order of derivative α. Then, we can observe the impact of fractional derivative α on the evolution of the model states. پرونده مقاله -
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21 - Coronavirus (covid-19) Transmission Dynamics with Vaccination: A Mathematical Model Analysis
Mengesha Firdawoke Mekash MohammedIn this paper, a nonlinear mathematical model of COVID-19 was developed. An SVEIHR model has been proposed using a system of ordinary differential equations. The model’s equilibrium points were found, and the model’s stability analysis and sensitivity analys چکیده کاملIn this paper, a nonlinear mathematical model of COVID-19 was developed. An SVEIHR model has been proposed using a system of ordinary differential equations. The model’s equilibrium points were found, and the model’s stability analysis and sensitivity analysis around these equilibrium points were investigated. The model’s basic reproduction number is investigated in the next-generation matrix. The disease free equilibrium of the COVID-19 model is stable if the basic reproduction number is less than unity; if the basic reproduction number is greater than unity, the disease free equilibrium is unstable. We also utilize numerical simulation to explain how each parameter affects the basic reproduction number. پرونده مقاله -
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22 - A Computational Approach for Fractal Mobile-Immobile Transport with Caputo-Fabrizio Fractional Derivative
Sadegh SadeghiThis paper deals with a spectral collocation method for the numerical solution of linear and nonlinear fractal Mobile/Immobile transport (FM/IT) model with Caputo-Fabrizio fractional derivative (C-F-FD). In the time direction, the finite difference procedure is used to چکیده کاملThis paper deals with a spectral collocation method for the numerical solution of linear and nonlinear fractal Mobile/Immobile transport (FM/IT) model with Caputo-Fabrizio fractional derivative (C-F-FD). In the time direction, the finite difference procedure is used to construct a semi-discrete problem and afterwards by applying a Chebyshev-spectral method, we obtain the approximate solution. The unconditional stability of the proposed method is proved which provides the theoretical basis of proposed method for solving the considered equation. Finally, some numerical experiments are included to clarify the efficiency and applicability of our proposed concepts in the sense of accuracy and convergence ratio. پرونده مقاله -
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23 - SPOT PATTERNS IN GRAY SCOTT MODEL WITH APPLICATION TO EPIDEMIC CONTROL
Muhammad Abdullahi Yau M. U. Adehi Muktari GarbaIn 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 چکیده کاملIn 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. پرونده مقاله -
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24 - پایداری عملکرد ژنوتیپ های امیدبخش نخود در کشت پائیزه با استفاده از روش GGEbiplot
پیام پزشکپور رحمت الله کریمی زاده امیر میرزائی محمد برزعلیهدف از انجام این تحقیق شناسایی ژنوتیپ های پر محصول و پایدار نخود در شرایط متفاوت محیطی بود. در این آزمایش 18 ژنوتیپ نخود در قالب طرح بلوک‌های کامل تصادفی در سه تکرار و در چهار ایستگاه تحقیقات کشاورزی شامل لرستان، ایلام، گچساران و گنبد به مدت دو سال زراعی (95-1393) در ش چکیده کاملهدف از انجام این تحقیق شناسایی ژنوتیپ های پر محصول و پایدار نخود در شرایط متفاوت محیطی بود. در این آزمایش 18 ژنوتیپ نخود در قالب طرح بلوک‌های کامل تصادفی در سه تکرار و در چهار ایستگاه تحقیقات کشاورزی شامل لرستان، ایلام، گچساران و گنبد به مدت دو سال زراعی (95-1393) در شرایط دیم مورد مقایسه قرار گرفتند. نتایج نشان داد که بیشترین و کمترین میزان عملکرد دانه به ترتیب در محیط‌های خرم‌آباد سال دوم (5/2911 کیلوگرم در هکتار) و ایلام سال اول (9/742 کیلوگرم در هکتار) به دست آمد. از بین ژنوتیپ‌های نخود مورد بررسی، بیشترین و کمترین میانگین عملکرد دانه به ترتیب به ژنو تیپ‌های G2 (47/1509 کیلوگرم در هکتار) و G13 (3/1266 کیلوگرم در هکتار) اختصاص داشت. سهم محیط، ژنو تیپ و اثر متقابل آن‌ها در تغییرات عملکرد دانه به ترتیب 7/87، 65/0 و 64/11 درصد بود. اثر متقابل ژنو تیپ و محیط با استفاده از مدل بای پلات تفکیک شد و طبق تجزیه مقادیر منفرد، دو مؤلفه اصلی اول به ترتیب 6/36=PC1 و 5/19=PC2 درصد از تغییرات کل داده‌ها را توجیه کردند. بر اساس نمودار GGE بای پلات، ژنو تیپ های G2، G6 و G12 از عملکرد دانه و پایداری بیشتری نسبت به سایر ژنو تیپ ها برخوردار بودند. ژنو تیپ G2 از طرفی عملکرد دانه بالاتری داشته و از طرف دیگر پایداری عملکرد نسبتاً بالاتری نیز نشان داد و به عنوان ژنو تیپ برتر نسبت به سایر ژنو تیپ‌ها معرفی گردید. پرونده مقاله
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