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1.
§1. IntroductionThispaperisconcernedwiththeasymptoticbehavioroftheoscillatorysolutionsofnonlin-earforcedneutraldelaydifferentialequationsoftheform[x(t)-∑mi=1pi(t)x(t-τi)]′ ∑nj=1qj(t)f(x(t-σj))=r(t), t≥t0,(1)wherepi,qj,r∈C([t0,∞),R),τi,σj≥0,i=1,2,…,m;j=1,2,…,n,f∈C(R,R),xf(x)>0forx≠0.Whenpi(t)≡0,i=1,2,…,m,Eq.(1)reducestox(t) ∑nj=1qj(t)f(x(t-σj))=r(t), t≥t0,(2)whoseasymptoticbehaviorofallsolutionshasbeenstudiedinJ.R.Yan[5].Whenr(t)≡0,f(x)≡xandm=n=1,Eq.(1)reducesto[…  相似文献   

2.
主要研究了二阶微分系统具有奇异正定超线性周期边值问题多重正解的存在性问题,利用Leray-Schauder抉择定理和锥不动点定理给出了奇异正定超线性周期边值问题-(p(t)x′)′+q1(t)x=f1(t,x,y),t∈I=[0,1]-(p(t)y′)′+q2(t)y=f2(t,x,y)x(0)=x(1),x[1](0)=x[1](1)y(0)=y(1),y[1](0)=y[1](1)(1.1)的多重正解的存在性,其中非线性项fi(t,x,y)(i=1,2)在x=∞,y=∞点处超线性,在(x,y)=(0,0)处具有奇性.这里定义x[1](t)=p(t)x′(t),y[1](t)=p(t)y′(t)为准导数,其中系数p(t),qi(t)(i=1,2)是定义在[0,1]上的可测函数,且p(t)>0,qi(t)>0(i=1,2),a.e[0,1],fi(t,x,y)∈C(I×R×R,R+),R+=(0,+∞).  相似文献   

3.
<正> 本文用[1]的求积法给出了下面的НСИУ组的近似解: (1)令w_i(t)=f_i[z,u_1(t),u_2(t)],i=1,2.假定函数f_i(t,,u_1,u_2),i=1,2,t∈(a,b),u_1,u_2∈(—∞,+∞),满足条件  相似文献   

4.
1IntroductionThetheoryofimpulsivedifferelltialequationsisanimportantbranchofdeferentialequations(see[1]).Inthispapertweconsidertheetistenceofininilnaland~malsolutionsfortheperindicboundaryValueproblems(PBVP)ofnonlinearimpulsiveintegrodmerentialequationsofmiredtypeinBanachspacewherejEC[JxExExE,E],J=[0,Zx],EisarealBanachspace10相似文献   

5.
张蕾  姜健飞 《数学季刊》2006,21(4):597-607
In this paper we introduce two sequences of operator functions and their dual functions:f_k(t)=((tlog t)~k-(t-1)~k)/(log~k 1t)(k=1,2,...),gk(t)=((t-1)~k-log~k t)/(log~k 1t)(k=1,2,...)and f_k~*=(t~klog~(k 1)t)/((tlog t)~k-(t-1)~k)(k=1,2,...),g_k~*(t)=(t~klog~(k 1)t)/((t-1)~k-log~k t)(k=1,2,...)definedon(0, ∞). We find that they are all operator monotone functions with respect to the strictly chaotic order and some ordinary orders among positive invertible operators.Indeed,we extend the results of the operator monotone function(tlog t -t 1)/(log~2t)which is widely used in the theory of heat transfer of the heat engineering and fluid mechanics[1].  相似文献   

6.
1.IntroductionThispaPerdealswiththenumericalsolutionofthefollowinginitialvalueproblemswherey:R-C,T(t)2oisthedelayterm,of(t):R-Cistheinitialfunction,whereasy(t)isunknownfort>o.Letusconsiderthefollowinglineardelaydifferentialequation:wherey:R-C,a3barecomplex,T>oisaconstantdelayW(t)denotesagivenfunctiononl-T,o].Itiswellknownthat(see[1,2]),ifW(t)iscontinuousandiflbl<-Re(a),(1-3)thenthesolutiony(t)to(1.2)tendstozeroast-+ooforeveryT>O.Inthiscasethesolutiony(t)to(1.2)iscaJledasymptoticallystab…  相似文献   

7.
§1 IntroductionAnvarovandLarinov[1]introducedthefollowingprey-predatorsystem:x(t)=x(t)[α-γy(t)-γ∫∞0K1(s)y(t-s)ds-∫∞0∫∞0R1(s,θ)y(t-s)y(t-θ)dθds],y(t)=y(t)[-β μx(t) μ∫∞0K2(s)x(t-s)ds ∫∞0∫∞0R2(s,θ)x(t-θ)x(t-s)dθds],(1)whereα,γ,βandμarepositiveconstants,Ki∈C([0,∞),(0,∞))andRi∈C([0,∞)×[0,∞),(0,∞)),i=1,2.Fortheecologicalsenseofsystem(1),wereferto[1,2]andrefer-encescitedtherein.Sincerealisticmodelsrequiretheinclusionoftheeffectofchangingen-vironment,itmot…  相似文献   

8.
1.IntroductionInthispaper,weinvestigatetheperiodicboundaryvalueproblem(PBVP)forfirstordernonlinearimpulsiveintegro-differentialeauationsofmixedtypeinaBanachspaceE:wherefEC[JxExExE,E],J=[0,2r]ticECIE,E](k=1,2,',m:KECID,R ],D={(t,s)EJxJ:t2s},HEC[JxJ,R ],R denotesthesetofallnonnegativenumbers,and0相似文献   

9.
1IntroductionInthispaper,wediscussthecompletesolutionoftheLinearNon-HomogeneousMatrixDifferentialEquations(LNHMDEs)describedbyA(p)PNH(t)=B(p)U(t),t2o,(1)wherepgd/dtthedifferentialoperator,A(p)=A,,Pq' A,,-1Pq1-' ' A1p AoERfa],",,rankR(.)A(p)=rlAieR",,i=O,1,2,',qi,qi>1,B(p)=Blpl BI-,P,-' -.' B1p BOeR[P],'",BjER'",j=o,1,2,...,l,l2o,PNH(t):[o, oc)-R'isthepseudostateoftheLNHMDE,u(f):[o, oo)-R"isanitimespiecewisecontinuouslydifferentiablefunctioncalledtheinputoftheLNHMDE…  相似文献   

10.
1IntroductionConsidertheneutraldifferentialequationswherepiERfori=l,2,...,m;o相似文献   

11.
A class of regression model selection criteria for the data with correlated errors is proposed. The proposed class of selection criteria is an estimator of weighted prediction risk. In addition, the proposed selection criteria are the generalizations of several commonly used criteria in statistical analysis. The theoretical and asymptotic properties for the class of criteria are established. Further, in the medium-sample case, the results based on a simulation study are quite consistent with the theoretical ones. The proposed criteria perform well in the simulations. Several applications are also given for a variety of statistical models.  相似文献   

12.
In this paper, we compare two modified Gaussian pseudolikelihood criteria (GPCs) with existing Gaussian pseudolikelihood criterion and empirical likelihood based criteria to choose the working correlation matrix in generalized estimating equations approach. Rich simulation studies are conducted to investigate the performance of these criteria under a range of model settings. The results show that the modified criteria outperform the original GPC and empirical likelihood based criteria in most cases in terms of selection accuracy. Empirical likelihood based criteria perform better to identify exchangeable structure in data with binary response. In the end, these criteria are applied to epilepsy seizure and Madras longitudinal schizophrenia study clinical data sets analysis.  相似文献   

13.
Two of the main approaches in multiple criteria optimization are optimization over the efficient set and utility function program. These are nonconvex optimization problems in which local optima can be different from global optima. Existing global optimization methods for solving such problems can only work well for problems of moderate dimensions. In this article, we propose some ways to reduce the number of criteria and the dimension of a linear multiple criteria optimization problem. By the concept of so-called representative and extreme criteria, which is motivated by the concept of redundant (or nonessential) objective functions of Gal and Leberling, we can reduce the number of criteria without altering the set of efficient solutions. Furthermore, by using linear independent criteria, the linear multiple criteria optimization problem under consideration can be transformed into an equivalent linear multiple criteria optimization problem in the space of linear independent criteria. This equivalence is understood in a sense that efficient solutions of each problem can be derived from efficient solutions of the other by some affine transformation. As a result, such criteria and dimension reduction techniques could help to increase the efficiency of existing algorithms and to develop new methods for handling global optimization problems arisen from multiple objective optimization.  相似文献   

14.
Prioritized OWA aggregation   总被引:2,自引:0,他引:2  
We indicate that the problem of prioritized criteria arises in situations in which there exists a relationship between the criteria so that lack of satisfaction by the higher priority criteria cannot be readily compensated for by satisfaction by lower priority criteria. Typical of this situation is the relationship between safety and cost. We consider the problem of criteria aggregation in this environment. Central to our approach is the use of importance weights to enforce this prioritization imperative. We apply our use of priority based importance weights to the case where the scope of the criteria aggregation is an OWA type aggregation.  相似文献   

15.
Two simple criteria for global robust stability of Hopfield-type interval neural networks with delay are presented. The criteria turn out to be modified versions of an earlier criterion due to Cao, Huang, and Qu. Examples show the effectiveness of the modified criteria. Numerical simulations are carried out to confirm the applicability of the modified criteria.  相似文献   

16.
In this technical note, equivalent stability criterion with minimal number of variables for three recently reported stability criteria is proposed for a class of linear systems with additive time-varying delays. The existing delay-dependent stability criteria for additive time-delay systems have more number of matrix variables in the LMI; and hence, they require more computational cost. The proposed equivalent criteria, unlike the original ones, encompass only the matrix variables that are associated in the Lyapunov-Krasovskii functional, making the criteria mathematically less complex and computationally more attractive. The complexity involved in the existing stability criteria is attributed to the fact the cross-terms that emanate from the time-derivative of the Lyapunov-Krasovskii functional are dealt with free-weighting matrices. Hence, apart from the matrix variables that are associated in the corresponding Lyapunov-Krasovskii functional, the existing criteria also have additional matrix variables in them. In this paper, we have devised techniques to eliminate the free-weighting matrices in the existing stability criteria without sacrificing the conservatism. The resulting equivalent stability criteria, therefore, have least possible number of variables in the LMI; and hence, have minimum computational burden. The effectiveness of the proposed equivalent criteria is validated on a numerical example.  相似文献   

17.
This paper proposes two types of alternative criteria of optimality for the continuous time portfolio selection problem. The optimality criteria, the so–called Laplace–Stieltjes transform (LST) criteria, are based on the assumption that the financial agent has a target level for the wealth accumulation process. These criteria are closely related to the so–called threshold stopping investment rule. We analytically derive the LST criteria and numerically compare them with the well–known Kelly criterion. It is shown that the portfolio strategies suggested may overcome the problem that the growth portfolio is often overestimated in several investment situations.  相似文献   

18.
研究一类高阶两项微分方程的振荡原则,利用变分原理及微分方程振荡性的扰动理论得到了此类微分方程的振荡与非振荡原则.  相似文献   

19.
Some novel, linear matrix inequality based, criteria for the uniqueness and global robust stability of the equilibrium point of Hopfield-type neural networks with delay are presented. A comparison of the present criteria with the previous criteria is made.  相似文献   

20.
Using a linear transformation similar to the Kummer transformation, some new oscillation criteria for linear Hamiltonian systems are established. These results generalize and improve the oscillation criteria due to I.S. Kumari and S. Umanaheswaram [I. Sowjaya Kumari, S. Umanaheswaram, Oscillation criteria for linear matrix Hamiltonian systems, J. Differential Equations 165 (2000) 174-198], Q. Yang et al. [Q. Yang, R. Mathsen, S. Zhu, Oscillation theorems for self-adjoint matrix Hamiltonian systems, J. Differential Equations 190 (2003) 306-329], and S. Chen and Z. Zheng [Shaozhu Chen, Zhaowen Zheng, Oscillation criteria of Yan type for linear Hamiltonian systems, Comput. Math. Appl. 46 (2003) 855-862]. These criteria also unify many of known criteria in literature and simplify the proofs.  相似文献   

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