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Global stability coefficient of large underground caverns under static loading and earthquake wave condition
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作者 CHEN Peng-fei JIANG Quan +3 位作者 LIU Jian LI Shao-jun CHEN Tao HE Ben-guo 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第8期2826-2843,共18页
Underground energy and resource development,deep underground energy storage and other projects involve the global stability of multiple interconnected cavern groups under internal and external dynamic disturbances.An ... Underground energy and resource development,deep underground energy storage and other projects involve the global stability of multiple interconnected cavern groups under internal and external dynamic disturbances.An evaluation method of the global stability coefficient of underground caverns based on static overload and dynamic overload was proposed.Firstly,the global failure criterion for caverns was defined based on its band connection of plastic-strain between multi-caverns.Then,overloading calculation of the boundary geostress and seismic intensity on the caverns model was carried out,and the critical unstable state of multi-caverns can be identified,if the plastic-strain band appeared between caverns during these overloading processes.Thus,the global stability coefficient for the multi-caverns under static loading and earthquake was obtained based on the corresponding overloading coefficient.Practical analysis for the Yingliangbao(YLB)hydraulic caverns indicated that this method can not only effectively obtain the global stability coefficient of caverns under static and dynamic earthquake conditions,but also identify the caverns’high-risk zone of local instability through localized plastic strain of surrounding rock.This study can provide some reference for the layout design and seismic optimization of underground cavern group. 展开更多
关键词 underground caverns global stability coefficient static-dynamic overload local instability
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A positive trend in the stability of global offshore wind energy
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作者 Chongwei Zheng 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2024年第1期123-134,共12页
The recognition on the trend of wind energy stability is still extremely rare,although it is closely related to acquisition efficiency,grid connection,equipment lifetime,and costs of wind energy utilization.Using the ... The recognition on the trend of wind energy stability is still extremely rare,although it is closely related to acquisition efficiency,grid connection,equipment lifetime,and costs of wind energy utilization.Using the 40-year(1979–2018)ERA-Interim data from the European Center for Medium-Range Weather Forecasts,this study presented the spatial-temporal distribution and climatic trend of the stability of global offshore wind energy as well as the abrupt phenomenon of wind energy stability in key regions over the past 40 years with the climatic analysis method and Mann-Kendall(M-K)test.The results show the following 5 points.(1)According to the coefficient of variation(C_(v))of the wind power density,there are six permanent stable zones of global offshore wind energy:the southeast and northeast trade wind zones in the Indian,Pacific and Atlantic oceans,the Southern Hemisphere westerly,and a semi-permanent stable zone(North Indian Ocean).(2)There are six lowvalue zones for both seasonal variability index(S_(v))and monthly variability index(M_(v))globally,with a similar spatial distribution as that of the six permanent stable zones.M_(v) and S_(v) in the Arabian Sea are the highest in the world.(3)After C_(v),M_(v) and S_(v) are comprehensively considered,the six permanent stable zones have an obvious advantage in the stability of wind energy over other sea areas,with C_(v) below 0.8,M_(v) within 1.0,and S_(v) within 0.7 all the year round.(4)The global stability of offshore wind energy shows a positive climatic trend for the past four decades.C_(v),M_(v) and S_(v) have not changed significantly or decreased in most of the global ocean during 1979 to2018.That is,wind energy is flat or more stable,while the monthly and seasonal variabilities tend to shrink/smooth,which is beneficial for wind energy utilization.(5)C_(v) in the low-latitude Pacific and M_(v) and S_(v) in both the North Indian Ocean and the low-latitude Pacific have an obvious abrupt phenomenon at the end of the20th century. 展开更多
关键词 global oceans wind energy stability spatial-temporal distribution climatic trend
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Probabilistic Global Maximum Power Point Tracking Algorithm for Continuously Varying Partial Shading Conditions on Autonomous PV Systems
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作者 Kha Bao Khanh Cao Vincent Boitier 《Energy and Power Engineering》 2024年第1期21-42,共22页
A photovoltaic (PV) string with multiple modules with bypass diodes frequently deployed on a variety of autonomous PV systems may present multiple power peaks under uneven shading. For optimal solar harvesting, there ... A photovoltaic (PV) string with multiple modules with bypass diodes frequently deployed on a variety of autonomous PV systems may present multiple power peaks under uneven shading. For optimal solar harvesting, there is a need for a control schema to force the PV string to operate at global maximum power point (GMPP). While a lot of tracking methods have been proposed in the literature, they are usually complex and do not fully take advantage of the available characteristics of the PV array. This work highlights how the voltage at operating point and the forward voltage of the bypass diode are considered to design a global maximum power point tracking (GMPPT) algorithm with a very limited global search phase called Fast GMPPT. This algorithm successfully tracks GMPP between 94% and 98% of the time under a theoretical evaluation. It is then compared against Perturb and Observe, Deterministic Particle Swarm Optimization, and Grey Wolf Optimization under a sequence of irradiance steps as well as a power-over-voltage characteristics profile that mimics the electrical characteristics of a PV string under varying partial shading conditions. Overall, the simulation with the sequence of irradiance steps shows that while Fast GMPPT does not have the best convergence time, it has an excellent convergence rate as well as causes the least amount of power loss during the global search phase. Experimental test under varying partial shading conditions shows that while the GMPPT proposal is simple and lightweight, it is very performant under a wide range of dynamically varying partial shading conditions and boasts the best energy efficiency (94.74%) out of the 4 tested algorithms. 展开更多
关键词 PHOTOVOLTAIC PV global Maximum Power Point tracking GMPPT Fast Varying Partial Shading Conditions Autonomous PV Systems GMPPT Review
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Global Stability Analysis of the Mathematical Model for Malaria Transmission between Vector and Host Population
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作者 Raghad Alsulami Amal Almatrafi +2 位作者 Nehad Almohammadi Hanin Alosaimi H. A. Batarfi 《American Journal of Computational Mathematics》 2024年第2期275-289,共15页
In this paper, we discuss a mathematical model of malaria transmission between vector and host population. We study the basic qualitative properties of the model, the boundedness and non-negativity, calculate all equi... In this paper, we discuss a mathematical model of malaria transmission between vector and host population. We study the basic qualitative properties of the model, the boundedness and non-negativity, calculate all equilibria, and prove the global stability of them and the behaviour of the model when the basic reproduction ratio R0 is greater than one or less than one. The global stability of equilibria is established by using Lyapunov method. Graphical representations of the calculated parameters and their effects on disease eradication are provided. 展开更多
关键词 Malaria Transmission global stability Lyapunov Function
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Fixed-Time Antidisturbance Consensus Tracking for Nonlinear Multiagent Systems With Matching and Mismatching Disturbances
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作者 Xiangmin Tan Chunyan Hu +3 位作者 Guanzhen Cao Qinglai Wei Wei Li Bo Han 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第6期1410-1423,共14页
In this paper,fixed-time consensus tracking for mul-tiagent systems(MASs)with dynamics in the form of strict feed-back affine nonlinearity is addressed.A fixed-time antidistur-bance consensus tracking protocol is prop... In this paper,fixed-time consensus tracking for mul-tiagent systems(MASs)with dynamics in the form of strict feed-back affine nonlinearity is addressed.A fixed-time antidistur-bance consensus tracking protocol is proposed,which consists of a distributed fixed-time observer,a fixed-time disturbance observer,a nonsmooth antidisturbance backstepping controller,and the fixed-time stability analysis is conducted by using the Lyapunov theory correspondingly.This paper includes three main improvements.First,a distributed fixed-time observer is developed for each follower to obtain an estimate of the leader’s output by utilizing the topology of the communication network.Second,a fixed-time disturbance observer is given to estimate the lumped disturbances for feedforward compensation.Finally,a nonsmooth antidisturbance backstepping tracking controller with feedforward compensation for lumped disturbances is designed.In order to mitigate the“explosion of complexity”in the tradi-tional backstepping approach,we have implemented a modified nonsmooth command filter to enhance the performance of the closed-loop system.The simulation results show that the pro-posed method is effective. 展开更多
关键词 Antidisturbance BACKSTEPPING consensus tracking fixed-time stability multiagent system(MASs) strict feedback affine nonlinear systems.
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Stability of second order Hopfield neural networks with time delays
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作者 Wang Shuna Liu Jiang 《江苏师范大学学报(自然科学版)》 CAS 2024年第3期49-55,共7页
Dynamical behaviors of a class of second order Hopfield neural networks with time delays is investigated.The existence of a unique equilibrium point is proved by using Brouwer's fixed point theorem and the counter... Dynamical behaviors of a class of second order Hopfield neural networks with time delays is investigated.The existence of a unique equilibrium point is proved by using Brouwer's fixed point theorem and the counter proof method,and some sufficient conditions for the global asymptotic stability of the equilibrium point are obtained through the combination of a suitable Lyapunov function and an algebraic inequality technique. 展开更多
关键词 Hopfield neural network Lyapunov function existence and uniqueness global asymptotic stability
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Global Stability in a Graph p-Laplacian SIR Epidemic ModelS
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作者 Ling Zhou Yu Zhang Zuhan Liu 《Journal of Applied Mathematics and Physics》 2023年第12期3962-3969,共8页
A p-Laplacian ( p > 2 ) reaction-diffusion system on weighted graphs is introduced to a networked SIR epidemic model. After overcoming difficulties caused by the nonlinear p-Laplacian, we show that the endemic equi... A p-Laplacian ( p > 2 ) reaction-diffusion system on weighted graphs is introduced to a networked SIR epidemic model. After overcoming difficulties caused by the nonlinear p-Laplacian, we show that the endemic equilibrium is globally asymptotically stable if the basic reproduction number r<sub>0</sub> is greater than 1, while the disease-free equilibrium is globally asymptotically stable if r<sub>0</sub> is lower than 1. We extend the stability results of SIR models with graph Laplacian ( p = 2 ) to general graph p-Laplacian. 展开更多
关键词 P-LAPLACIAN NETWORK global stability Lyapunov Function
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Vision-based fatigue crack detection using global motion compensation and video feature tracking
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作者 Rushil Mojidra Jian Li +3 位作者 Ali Mohammadkhorasani Fernando Moreu Caroline Bennett William Collins 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2023年第1期19-39,共21页
Fatigue cracks that develop in civil infrastructure such as steel bridges due to repetitive loads pose a major threat to structural integrity.Despite being the most common practice for fatigue crack detection,human vi... Fatigue cracks that develop in civil infrastructure such as steel bridges due to repetitive loads pose a major threat to structural integrity.Despite being the most common practice for fatigue crack detection,human visual inspection is known to be labor intensive,time-consuming,and prone to error.In this study,a computer vision-based fatigue crack detection approach using a short video recorded under live loads by a moving consumer-grade camera is presented.The method detects fatigue crack by tracking surface motion and identifies the differential motion pattern caused by opening and closing of the fatigue crack.However,the global motion introduced by a moving camera in the recorded video is typically far greater than the actual motion associated with fatigue crack opening/closing,leading to false detection results.To overcome the challenge,global motion compensation(GMC)techniques are introduced to compensate for camera-induced movement.In particular,hierarchical model-based motion estimation is adopted for 2D videos with simple geometry and a new method is developed by extending the bundled camera paths approach for 3D videos with complex geometry.The proposed methodology is validated using two laboratory test setups for both in-plane and out-of-plane fatigue cracks.The results confirm the importance of motion compensation for both 2D and 3D videos and demonstrate the effectiveness of the proposed GMC methods as well as the subsequent crack detection algorithm. 展开更多
关键词 global motion compensation fatigue crack detection computer vision parallax effect distortion induced fatigue crack video stabilization camera motion in-plane fatigue crack out-of-plane fatigue crackanalysis
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Electronic image stabilization system based on global feature tracking 被引量:7
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作者 Zhu Juanjuan Guo Baolong 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2008年第2期228-233,共6页
A new robust electronic image stabilization system is presented, which involves feature-point, tracking based global motion estimation and Kalman filtering based motion compensation. First, global motion is estimated ... A new robust electronic image stabilization system is presented, which involves feature-point, tracking based global motion estimation and Kalman filtering based motion compensation. First, global motion is estimated from the local motions of selected feature points. Considering the local moving objects or the inevitable mismatch, the matching validation, based on the stable relative distance between the points set is proposed, thus maintaining high accuracy and robustness. Next, the global motion parameters are accumulated for correction by Kalman filteration. The experimental result illustrates that the proposed system is effective to stabilize translational, rotational, and zooming jitter and robust to local motions. 展开更多
关键词 electronic image stabilization global motion estimation feature tracking Kalman filter.
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Discounted Iterative Adaptive Critic Designs With Novel Stability Analysis for Tracking Control 被引量:9
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作者 Mingming Ha Ding Wang Derong Liu 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2022年第7期1262-1272,共11页
The core task of tracking control is to make the controlled plant track a desired trajectory.The traditional performance index used in previous studies cannot eliminate completely the tracking error as the number of t... The core task of tracking control is to make the controlled plant track a desired trajectory.The traditional performance index used in previous studies cannot eliminate completely the tracking error as the number of time steps increases.In this paper,a new cost function is introduced to develop the value-iteration-based adaptive critic framework to solve the tracking control problem.Unlike the regulator problem,the iterative value function of tracking control problem cannot be regarded as a Lyapunov function.A novel stability analysis method is developed to guarantee that the tracking error converges to zero.The discounted iterative scheme under the new cost function for the special case of linear systems is elaborated.Finally,the tracking performance of the present scheme is demonstrated by numerical results and compared with those of the traditional approaches. 展开更多
关键词 Adaptive critic design adaptive dynamic programming(ADP) approximate dynamic programming discrete-time nonlinear systems reinforcement learning stability analysis tracking control value iteration(VI)
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Global Asymptotic Stability of Neural Networks with Time Delay
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作者 肖晓丹 张洁 《科技信息》 2008年第19期207-208,共2页
The global asymptotic stability problem of Cellular neural networks with delay is investigated.A new stability condition is presented based on Lyapunov-Krasovskii method,which is dependent on the size of delay.The res... The global asymptotic stability problem of Cellular neural networks with delay is investigated.A new stability condition is presented based on Lyapunov-Krasovskii method,which is dependent on the size of delay.The result is given in the form of LMI,and the admitted upper bound of the delay can be obtained easily.The time delay dependent and independent results can be obtained,which include some results in the former literature.Finally,a numerical example is given to illustrate the effectiveness of the main results. 展开更多
关键词 时间延迟 神经网络 自动化系统 稳定性
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Modeling and small-signal stability analysis of doubly-fed induction generator integrated system 被引量:1
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作者 Tianming Gu Puyu Wang +3 位作者 Dingyuan Liu Ao Sun Dejian Yang Gangui Yan 《Global Energy Interconnection》 EI CSCD 2023年第4期438-449,共12页
Owing to their stability,doubly-fed induction generator(DFIG)integrated systems have gained considerable interest and are the most widely implemented type of wind turbines and due to the increasing escalation of the w... Owing to their stability,doubly-fed induction generator(DFIG)integrated systems have gained considerable interest and are the most widely implemented type of wind turbines and due to the increasing escalation of the wind generation penetration rate in power systems.In this study,we investigate a DFIG integrated system comprising four modules:(1)a wind turbine that considers the maximum power point tracking and pitch-angle control,(2)induction generator,(3)rotor/grid-side converter with the corresponding control strategy,and(4)AC power grid.The detailed small-signal modeling of the entire system is performed by linearizing the dynamic characteristic equation at the steady-state value.Furthermore,a dichotomy method is proposed based on the maximum eigenvalue real part function to obtain the critical value of the parameters.Root-locus analysis is employed to analyze the impact of changes in the phase-locked loop,short-circuit ratio,and blade inertia on the system stability.Lastly,the accuracy of the small-signal model and the real and imaginary parts of the calculated dominant poles in the theoretical analysis are verified using PSCAD/EMTDC. 展开更多
关键词 Doubly-fed induction generator(DFIG) Maximum power point tracking DICHOTOMY Small-signal stability
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PERSISTENCE AND GLOBAL STABILITY FOR A THREE-SPECIES RATIO-DEPENDENT PREDATOR-PREY SYSTEM WITH TIME DELAYS IN TWO-PATCH ENVIRONMENTS 被引量:12
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作者 徐瑞 陈兰荪 《Acta Mathematica Scientia》 SCIE CSCD 2002年第4期533-541,共9页
A three-species ratio-dependent predator-prey diffusion model with time delays is investigated. It is shown that the system is uniformly persistent under some appropriate conditions, and sufficient conditions axe obta... A three-species ratio-dependent predator-prey diffusion model with time delays is investigated. It is shown that the system is uniformly persistent under some appropriate conditions, and sufficient conditions axe obtained for the global stability of the positive equilibrium of the system. 展开更多
关键词 time delay diffusion uniform persistence global asymptotic stability
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Stabilization and trajectory tracking of autonomous airship's planar motion 被引量:7
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作者 Zhang Yan Qu Weidong +1 位作者 Xi Yugeng Cai Zili 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2008年第5期974-981,共8页
The stabilization and trajectory tracking problems of autonomous airship's planar motion are studied. By defining novel configuration error and velocity error, the dynamics of error systems are derived. By applying L... The stabilization and trajectory tracking problems of autonomous airship's planar motion are studied. By defining novel configuration error and velocity error, the dynamics of error systems are derived. By applying Lyapunov stability method, the state feedback control laws are designed and the close-loop error systems are proved to be uniformly asymptotically stable by Matrosov theorem. In particular, the controller does not need knowledge on system parameters in the case of set-point stabilization, which makes the controller robust with respect to parameter uncertainty. Numerical simulations illustrate the effectiveness of the controller designed. 展开更多
关键词 AIRSHIP planar motion stabilIZATION trajectory tracking ROBUSTNESS Lyapunov stability Matrosov theorem.
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GLOBAL STABILITY OF AN SIRS EPIDEMIC MODEL WITH DELAYS 被引量:14
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作者 靳祯 马知恩 韩茂安 《Acta Mathematica Scientia》 SCIE CSCD 2006年第2期291-306,共16页
In this article, an SIRS epidemic model spread by vectors (mosquitoes) which have an incubation time to become infectious is formulated. It is shown that a disease-free equilibrium point is globally stable if no end... In this article, an SIRS epidemic model spread by vectors (mosquitoes) which have an incubation time to become infectious is formulated. It is shown that a disease-free equilibrium point is globally stable if no endemic equilibrium point exists. Further, the endemic equilibrium point (if it exists) is globally stable with a respect "weak delay". Some known results are generalized. 展开更多
关键词 SIRS epidemic model time delay global asymptotic stability lyapunov functional
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GLOBAL ASYMPTOTIC STABILITY OF THE PERIODIC LOTKA-VOLTERRA SYSTEM WITH TWO-PREDATORS AND ONE-PREY 被引量:15
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作者 LUZHONGHUA CHENLANSUN 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 1995年第3期267-274,共8页
The three species Lotka-Volterra periodic model with two predators and one prey is considered.A set of easily verifiable sufficient conditions is obtained.Finallyt an example is given to illustrate the feasibility of ... The three species Lotka-Volterra periodic model with two predators and one prey is considered.A set of easily verifiable sufficient conditions is obtained.Finallyt an example is given to illustrate the feasibility of these conditions. 展开更多
关键词 PERIODIC EXISTENCE global asymptotic stability
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GLOBAL ASYMPTOTIC STABILITY IN N-SPECIES NONAUTONOMOUS LOTKA-VOLTERRACOMPETITIVE SYSTEMS WITH DELAYS 被引量:12
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作者 徐瑞 陈兰荪 M.A.J.Chaplain 《Acta Mathematica Scientia》 SCIE CSCD 2003年第2期208-218,共11页
A delayed n-species nonautonomous Lotka-Volterra type competitive system without dominating instantaneous negative feedback is investigated. By means of a suitable Lyapunov functional, sufficient conditions are derive... A delayed n-species nonautonomous Lotka-Volterra type competitive system without dominating instantaneous negative feedback is investigated. By means of a suitable Lyapunov functional, sufficient conditions are derived for the global asymptotic stability of the positive solutions of the system. As a corollary, it is shown that the global asymptotic stability of the positive solution is maintained provided that the delayed negative feedbacks dominate other interspecific interaction effects with delays and the delays are sufficiently small. 展开更多
关键词 Nonautonomous Lotka-Volterra competitive system finite and infinite delay global asymptotic stability Lyapunov functional
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GLOBAL STABILITY OF EXTENDED MULTI-GROUP SIR EPIDEMIC MODELS WITH PATCHES THROUGH MIGRATION AND CROSS PATCH INFECTION 被引量:7
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作者 Yoshiaki MUROYA Yoichi ENATSU Toshikazu KUNIYA 《Acta Mathematica Scientia》 SCIE CSCD 2013年第2期341-361,共21页
In this article, we establish the global stability of an endemic equilibrium of multi-group SIR epidemic models, which have not only an exchange of individuals between patches through migration but also cross patch in... In this article, we establish the global stability of an endemic equilibrium of multi-group SIR epidemic models, which have not only an exchange of individuals between patches through migration but also cross patch infection between different groups. As a result, we partially generalize the recent result in the article [16]. 展开更多
关键词 multi-group SIR epidemic model PATCH global asymptotic stability Lyapunovfunction
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ON GLOBAL STABILITY OF A NONRESIDENT COMPUTER VIRUS MODEL 被引量:6
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作者 Yoshiaki MUROYA Huaixing LI Toshikazu KUNIYA 《Acta Mathematica Scientia》 SCIE CSCD 2014年第5期1427-1445,共19页
In this paper, we establish new sufficient conditions for the infected equilibrium of a nonresident computer virus model to be globally asymptotically stable. Our results extend two kind of known results in recent lit... In this paper, we establish new sufficient conditions for the infected equilibrium of a nonresident computer virus model to be globally asymptotically stable. Our results extend two kind of known results in recent literature. 展开更多
关键词 nonresident computer virus model PERMANENCE global asymptotic stability Lyapunov function
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GLOBAL ASYMPTOTIC STABILITY FOR A NONLINEAR DELAY DIFFERENCE EQUATION 被引量:7
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作者 LiXianyi ZhuDeming 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2002年第2期183-188,共6页
In this paper,a sufficient condition for the global asymptotic stability of the solutions of the following nonlinear delay difference equation is obtained, xn+ 1=xn+xn- 1xn- 2 +a xnxn- 1+xn- 2 +a, n =0 ,1 ,..., ... In this paper,a sufficient condition for the global asymptotic stability of the solutions of the following nonlinear delay difference equation is obtained, xn+ 1=xn+xn- 1xn- 2 +a xnxn- 1+xn- 2 +a, n =0 ,1 ,..., where a∈ [0 ,∞ ) and the initial values x- 2 ,x- 1,x0 ∈ (0 ,∞ ) .As a special case,a conjecture by Ladas is confirmed. 展开更多
关键词 nonlinear delay difference equation global asymptotic stability SEMICYCLE
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