共查询到20条相似文献,搜索用时 15 毫秒
1.
STUDY ON AN SIS EPIDEMIC MODEL WITH TIME VARIANT DELAY 总被引:1,自引:1,他引:0
YUAN Sanling MA Zhien 《系统科学与复杂性》2002,15(3):299-306
In this paper, we study an SIS epidemic model with a time variant delay. By means of Liapunov functional, some sufficient conditions of global stability to endemic equilibrium and disease free equilibrium have been obtained. The influence of time delay on the stability of equilibria is displayed. 相似文献
2.
CUI Jing''''an 《系统科学与复杂性》1994,(1)
GLOBALASYMPTOTICSTABILITYINN-SPECIESCOOPERATIVESYSTEMWITHTIMEDELAYS¥CUIJing'an(DepartmentofMathematics,XinjingUniversity,Urum... 相似文献
3.
ON AN SIS EPIDEMIC MODEL WITH STAGE STRUCTURE 总被引:8,自引:0,他引:8
XIAOYanni CHENLansun 《系统科学与复杂性》2003,16(2):275-288
A SIS infectious disease model with stage structure consisting of immature and mature stages is proposed using a discrete time delay. The aim of the paper is to investigate under which conditions the disease becomes endemic or not and to find the difference between the model with stage structure and the corresponding model without stage structure. It is shown that either there exists a unique endemic equilibrium point which is globally asymptotically stable or the disease dies out by using an iterative scheme. The effect of the time delay on the populations at equilibria is considered. 相似文献
4.
JIANGLiqiang MAZhien P.Fergola 《系统科学与复杂性》2005,18(1):19-26
In this paper, by applying the method of Liapunov functionals we study the global stability of the positive equilibrium of a competing chemostat model with delayed nutrient recycling. The sufficient conditions of the global stability (involved in average time delay or not) are obtained. 相似文献
5.
QIUZhipeng 《系统科学与复杂性》2005,18(3):396-403
In this paper, the asymptotic behavior of three types of population models with delays and diffusion is studied. The first represents one species growth in the patch Ω and periodic environment and with delays recruitment, the second models a single species dispersal among the m patches of a heterogeneous environment, and the third models the spread of bacterial infections. Sufficient conditions for the global attractivity of periodic solution are obtained by the method of monotone theory and strongly concave operators. Some earlier results are extended to population models with delays and diffusion. 相似文献
6.
井竹君 《系统科学与复杂性》1989,(4)
A predator-prey system,depending on several parameters,is investigated forbifurcation of equilibria,Hopf bifurcation,global bifurcation occurring saddle connection,and global existence and nonexistence of limit cycles,and changes of the topological structureof trajectory as parameters are varied. 相似文献
7.
GLOBAL AND LOCAL BIFURCATION IN PERTURBATIONS OF NON-SYMMETRY AND SYMMETRY OF HAMILTONIAN SYSTEM 总被引:3,自引:0,他引:3
LIU Zhengrong 《系统科学与复杂性》1995,(4)
GLOBALANDLOCALBIFURCATIONINPERTURBATIONSOFNON-SYMMETRYANDSYMMETRYOFHAMILTONIANSYSTEM¥LIUZhengrong(InstituteofAppliedMathemati... 相似文献
8.
THE HOPF BIFURCATION DIRECTION OF A FOUR DIMENSIONAL ELECTRONIC NEURAL NETWORK SYSTEM 总被引:2,自引:0,他引:2
1.IntroductionCurrentlybifurcationtheoryiswidelyusedinmanymathematicalmodelsofvariousfieldssuchasbiologyjmechanics,medicalscience,managementofnaturalresourcesandthetheoryofneuralnetowrks.Inadifferentialdynamicalsystem,averyimportalltproblemistheexistencea… 相似文献
9.
A system of three-unit networks with coupled cells is investigated.The general formula for bifurcation direction of Hopf bifurcation is calculated and the estimate formula of period of the periodic solution is given. 相似文献
10.
CHEN Jufang 《系统科学与复杂性》1997,(3)
1.IntroductionDifferellceequationswithtimedelayhavebeenanimportantclassofmathematicallllodels.Fol'instance,inbiology,systemsofdifferenceequationshavebeedmuchusedtomodeltheinteractiollsofspecieswithlion-overlappinggeneration,butthemodelwillberelatedtodifferenceequationswithtimedelaywhenollemustconsidertheinfluenceoftimedelayeffectforspecies11limber.Thereisextensiveresearchondifferentialequationswithtimedelaybutthereisoillylittleworkdoneondifferenceequationswithtimedelay.Ouraimistoestablishstabi… 相似文献
11.
MENG Xinzhu 《系统科学与复杂性》2005,18(4):488-497
The uniform permanence and global asymptotic stability of a class of almost periodic Lotka-Volterra type N-species competitive systems with diffusion and delays are investigated. It is shown that the system is uniformly persistent under some appropriate conditions, and new sufficient conditions are obtained for the global asymptotic stability of the unique positive almost periodic solution of the system. 相似文献
12.
WU Jianhua 《系统科学与复杂性》1994,(3)
STABILITYOFSTEADY-STATESOLUTIONSOFTHECOMPETITIONMODELINTHECHEMOSTAT¥WUJianhua(Xi'anInstituteofHighway,Xi,an710064,China)LIYan... 相似文献
13.
SONGXinyu CHENLansun 《系统科学与复杂性》2002,15(3):307-314
In this paper, we consider a nonautonomous competitive model with dispersion and a finite number of discrete delays. The system, which consists of two Lotka-Volterra patches, has two competitors: one can disperse between the two patches, but the other is confined to one patch and cannot disperse. Our purpose is to demonstrate that the dispersion rates have no effect on the uniform persistence of the solutions of the system. Furthermore, we establish the conditions under which the system admits a positive periodic solution which attracts all solutions. 相似文献
14.
A STAGE-STRUCTURED SI ECO-EPIDEMIOLOGICAL MODEL WITH TIME DELAY AND IMPULSIVE CONTROLLING* 总被引:1,自引:0,他引:1
This paper formulates a robust stage-structured SI eco-epidemiological model with periodic constant pulse releasing of infectious pests with pathogens. The authors show that the conditions for global attractivity of the 'pest-eradication' periodic solution and permanence of the system depend on time delay, hence, the authors call it "profitless". Further, the authors present a pest management strategy in which the pest population is kept under the economic threshold level (ETL) when the pest population is uniformly persistent. By numerical analysis, the authors also show that constant maturation time delay for the susceptible pests and pulse releasing of the infectious pests can bring obvious effects on the dynamics of system. 相似文献
15.
YANG Xiaojing 《系统科学与复杂性》1997,(1)
1.IntroductionT.Dated]obtainedanalgebraicclassificationofplanehomogeneousquadraticvectorfields,A.Cima[2]gaveanalgebraicandtopologicalclassificationofhomogeneouscubicvectorfieldsintheplane.Theirmethodswerebasedontheclassificationofforth-orderbinaryformsdev… 相似文献
16.
LING Jiaoxiu WENG Peixuan 《系统科学与复杂性》2005,18(4):464-477
In this paper, we derive a lattice model for a single species on infinite patches of one-dimensional space with that the maturation could occur at any age. The formulation involves a distribution of possible ages of maturation and a probability density function on which ecological assumptions are made. The following results are obtained: the existence and isotropy of the unique nonnegative solution for initial value problem, the extinction of the species provided with the non-existence of positive equilibria, and the existence of wavefronts with the wave speed c 〉 c*. 相似文献
17.
The present paper deals with the periodic behaviours of an age-structured populationmodel.The period-similarity is proposed,which reveals a certain similar structure between thosepopulation models with distinct age structure.In addition,other results show that the fluctuations ofan age-structured population are closely related with the age structure. 相似文献
18.
HUANGHaivang LIULaifu 《系统科学与复杂性》2003,16(1):19-29
In this paper the existence and stability of the positive equilibrium of the size-structured population model are proved by Rabinowitz‘s theorem and the local linearization method.The result here shows that near the bifurcation point where a branch of positive equilibria appears,the stability of the positive equilibrium on the branch is dcpendent on the direction of the bifurcation.The argument for the model of age-structured population is generalized in this paper. 相似文献
19.
1.IntroductionTheconceptsofrelativedegreeandzerodynamicshavebeenproposedbyByrnes,Isidoriandotherstotreatlocalfeedbackstabilizationproblemofnonlinearcolltrolsystems.Oneofthekeypointsforthismethodistousecelltermanifoldtheory.[1]wasoneoftheearliestworksusingcentermanifoldtechniqueinthisarea.Firstofall,wewilldescribethecentermanifoldmethodthroughanexampletoshowhowthecentermanifoldmethodcanbeusedtosolvethestabilizationproblem.Forconvenience,wecitesomebasicresultsfrom[2].Theorem1.1Considerasystemw… 相似文献
20.
YULean WANGShouyang K.K.Lai Y.Nakamori 《系统科学与复杂性》2005,18(1):1-18
Various mathematical models have been commonly used in time series analysis and forecasting. In these processes, academic researchers and business practitioners often come up against two important problems. One is whether to select an appropriate modeling approach for prediction purposes or to combine these different individual approaches into a single forecast for the different/dissimilar modeling approaches. Another is whether to select the best candidate model for forecasting or to mix the various candidate models with different parameters into a new forecast for the same/similar modeling approaches. In this study, we propose a set of computational procedures to solve the above two issues via two judgmental criteria. Meanwhile, in view of the problems presented in the literature, a novel modeling technique is also proposed to overcome the drawbacks of existing combined forecasting methods. To verify the efficiency and reliability of the proposed procedure and modeling technique, the simulations and real data examples are conducted in this study.The results obtained reveal that the proposed procedure and modeling technique can be used as a feasible solution for time series forecasting with multiple candidate models. 相似文献