parasite population delay model of malaria type with stochastic perturbation and environmental criterion for limitation of disease we present a stochastic delay model of an infectious disease malaria transmitted by a vectors mosquitoes after an incubation time a criterion for limitation of disease is found

global dynamics for a new high dimensional sir model with distributed delay abstract in this paper a new high dimensional sir epidemic model with double epidemic hypothesis and delays is proposed which is a high dimensional system of impulsive functional differential equations with time delays the linear chain trick technique is employed to prove the upper boundedness of solutions of the impulsive delay differential equations and scaling method techniques for inequalities and classification method are used to study the permanence of the high dimensional system we also prove that the infection free periodic solution of the system is globally attractive when r 1 1 and the system is permanent under r 2 1 moreover numerical simulation for impulsive and delayed system is presented to illustrate our main conclusions which shows that time delays and pulse vaccination have significant effects on the dynamics behaviors of the model the feature of the present paper is that the double epidemic hypothesis have different forms of delays to more realistically describe the spread of epidemic though which makes the high dimensional system more complex

dynamic behavior for a nonautonomous sirs epidemic model with distributed delays a nonautonomous sirs epidemic model with distributed delay is investigated two new threshold values r and r are derived the model is permanent as r 1 and r 1 implies the extinction of the disease using the liapunov functional method global behavior of the model is studied

traveling waves for a diffusive sir model with delay abstract in this paper we study traveling waves connecting the infection free equilibrium state and the endemic equilibrium state for a diffusive sir model with delay and saturated incidence rate since this system does not enjoy the comparison principle we will use an iteration process to construct a pair of upper and lower solutions with the aid of the pair of upper and lower solutions we can apply the schauder fixed point theorem to construct a family of solutions of the truncated problems which via the limiting argument can generate the traveling wave indeed we show that there exists c 0 such that this system admits a traveling wave solution with speed c iff c c

global stability of a delayed sir epidemic model with density dependent birth and death rates an sir epidemic model with density dependent birth and death rates is formulated in our model it is assumed that the total number of the population is governed by logistic equation the transmission of infection is assumed to be of the standard form namely proportional to i t h n t h where n t is the total variable population size i t is the size of the infective population and a time delay h is a fixed time during which the infectious agents develop in the vector we consider transmission dynamics for the model stability of an endemic equilibrium is investigated the stability result is stated in terms of a threshold parameter that is a basic reproduction number r 0

exact closed form frequency equations for thick circular plates using a third order shear deformation theory abstract this paper presents for the first time exact closed form frequency equations and transverse displacement for thick circular plates with free soft simply supported hard simply supported and clamped boundary conditions based on reddy s third order shear deformation theory hamiltonian and minimum potential energy principles are used to extract the equations of dynamic equilibrium and natural boundary conditions of the plate the new formulation is verified by comparing the results with their counterparts reported in open literature natural frequencies of circular plates with different boundary conditions are tabulated in dimensionless form for various values of thickness radius ratios the results presented on the basis of exact closed form frequency equations are expected to serve as reliable benchmarks

blind adaptive spatiotemporal filtering for wide band cyclostationary signals an algorithm that blindly adapts spatiotemporal filters to extract from sensor array data one or more desired signals having known cyclostationarity properties is presented this method referred to as the spectral self coherence restoral score method can accommodate multiple signals of interest multiple interferers and unknown noise does not require complicated searches and requires knowledge of only a cycle frequency of the desired signal the score method is reinterpreted using the framework of canonical correlation analysis and extended to accommodate wide band received data that do not adhere to the narrow band assumption background information on cyclostationarity is presented and canonical correlation analysis is explained briefly the score method for wide band array data is from the perspective of canonical correlation analysis results of computer simulations are presented to illustrate the performance of the method and to compare it with that of the minimum variance distortionless response beamformer

complete global analysis of a two scale network sirs epidemic dynamic model with distributed delay and random perturbations the model validation results are established the basic reproduction numbers at three human vector contact levels are computed the stochastic stability of equilibria is proven interplay between stability and human mobility are exhibited in real life scenarios a stochastic sirs epidemic dynamic model with distributed time delay for vector borne diseases in two scale network structured populations is presented the distributed delay accounts for the varying incubation period of the disease furthermore the disease dynamics is influenced by random environmental perturbations in the disease transmission process as well as the two scale human mobility process the basic reproduction numbers at three human vector contact levels in the two scale population are computed and the results for the stochastic asymptotic stability of the equilibria are presented moreover the asymptotic stability results are exhibited in several real life scenarios and the significance of the results are presented numerical simulation results are presented

natural frequency information for circular and annular plates abstract this paper presents the results of an extensive literature search and review of available sources of numerical natural frequency information for stationary circular and annular elastic plates in addition to the source information is given regarding the specific plate theory boundary conditions geometric properties and material properties used to determine the natural frequency information sources of information are tabulated according to the above parameters for easy reference and selection of desired information a description of the various plate theories including the basic governing partial differential equation of motion is also given this information may be particularly useful to experimentalists and designers when natural frequency data are required without the need for detailed analysis

convergence results in a well known delayed predator prey system abstract in this paper we provide a detailed and explicit procedure of obtaining some regions of attraction for the positive steady state assumed to exist of a well known lotka volterra type predator prey system with a single discrete delay our procedure requires the delay length to be small a detailed example is presented the method used here is to construct a proper liapunov functional in a restricted region

stability analysis of delayed sir epidemic models with a class of nonlinear incidence rates we analyze stability of equilibria for a delayed sir epidemic model in which population growth is subject to logistic growth in absence of disease with a nonlinear incidence rate satisfying suitable monotonicity conditions the model admits a unique endemic equilibrium if and only if the basic reproduction number r0 exceeds one while the trivial equilibrium and the disease free equilibrium always exist first we show that the disease free equilibrium is globally asymptotically stable if and only if r0 1 second we show that the model is permanent if and only if r0 1 moreover using a threshold parameter r0 characterized by the nonlinear incidence function we establish that the endemic equilibrium is locally asymptotically stable for 1 r0 r0 and it loses stability as the length of the delay increases past a critical value for 1 r0 r0 our result is an extension of the stability results in j j wang j z zhang z jin analysis of an sir model with bilinear incidence rate nonl anal rwa 11 2009 2390 2402

spurious and true eigensolutions of helmholtz bies and bems for a multiply connected problem the spurious eigenvalues of an annular domain have been verified for the singular and hypersingular boundary element methods bems and circumvented by using the burton miller approach do they also occur in other formulations continuous formulations such as the singular and hypersingular boundary integral equations bies the null field bies and the fictitious bies or such discrete formulations as the null field bems and the fictitious bems for the ten formulations of the multiply connected problem the study of otherwise the same issues is continued in the present paper by using the degenerate kernels and the fourier series it is demonstrated analytically for the six continuous formulations of bies that spurious eigensolutions depend on the geometry of the inner boundary but not on that of the outer boundary this conclusion can be extended to the six discrete formulations of bems to filter out the spurious eigenvalues the chief combined helmholtz integral equation formulation method is used here instead of the burton miller approach the optimum number and appropriate positions of the chief points are also addressed it is then shown that in the null field and fictitious bems the spurious and true eigenvalues can be detected and distinguished by using the singular value decomposition updating techniques in conjunction with the fredholm alternative theorem illustrative examples show the validity of the proposed methodologies

global stability of a delayed sirs epidemic model with saturation incidence and temporary immunity in this paper a delayed sirs epidemic model with saturation incidence and temporary immunity is investigated the immunity gained by experiencing a disease is temporary whenever infected the diseased individuals will return to the susceptible class after a fixed period by analyzing the corresponding characteristic equations the local stability of an endemic equilibrium and a disease free equilibrium is discussed by comparison arguments it is proved that if the basic reproduction number is less than unity the disease free equilibrium is globally asymptotically stable if the basic reproduction number is greater than unity by means of an iteration technique sufficient conditions are obtained for the global asymptotic stability of the endemic equilibrium numerical simulations are carried out to illustrate the main theoretical results

asymptotic moments of estimated cyclic correlation matrices the first and second moments of the cyclic cross correlogram matrix of two vector valued cyclostationary processes are derived in this paper these results generalize those of hurd 1989 to accommodate incommensurate cycle frequencies and complex vector valued discrete time nongaussian processes as an example application of the results the moments of the left singular vectors of the cyclic cross correlogram matrix are derived which are needed in the performance analysis of subspace fitting methods of direction of arrival estimation for cyclostationary signals including even those methods that do not exploit cyclostationarity but are often applied in practice to cyclostationary signals

stability and bifurcation analysis of a delayed predator prey model of prey dispersal in two patch environments abstract in this paper a class of delayed predator prey model of prey dispersal in two patch environments is considered by analyzing the associated characteristic transcendental equation its linear stability is investigated and hopf bifurcation is demonstrated some explicit formulae determining the stability and the direction of the hopf bifurcation periodic solutions bifurcating from hopf bifurcations are obtained by using the normal form theory and center manifold theory some numerical simulation for justifying the theoretical analysis are also provided finally biological explanations and main conclusions are given

collocation approach to the helmholtz eigenvalue problem on multiply connected domains we present a collocation approach to the numerical solution of the helmholtz eigenvalue problem on multiply connected domains of arbitrary shape in two dimensions a suitable representation of the helmholtz equation on an uniform grid is obtained and the problem is converted to the calculation of the first few eigenvalues and eigenvectors of a large sparse matrix the accuracy of this approach is tested by performing a comparison with results available in the literature the flexibility and simplicity of the method make easy the application to arbitrary geometries

permanence of an sir epidemic model with density dependent birth rate and distributed time delay abstract in this paper we investigate the permanence of an sir epidemic model with a density dependent birth rate and a distributed time delay we first consider the attractivity of the disease free equilibrium and then show that for any time delay the delayed sir epidemic model is permanent if and only if an endemic equilibrium exists numerical examples are given to illustrate the theoretical analysis the results obtained are also compared with those from the analog system with a discrete time delay

the vibration modes of concentrically supported free circular plates abstract vibration of a circular plate internally concentrically supported is basic in structural mechanics the complete first six frequencies and mode shapes are determined for clamped simply supported sliding and ring supports using exact characteristic frequency equations complex mode switches occur as the support radius is varied asymptotic formulas for large support radii are derived different types of singularities as the support radius shrinks to zero are distinguished and classified

vibration of annular plate concentrators with conical cross section in this paper the torsional vibration and radial vibration of isotropic metal thin annular plates with conical cross section are deduced by using bessel functions and according to electro mechanical analogy the electro mechanical equivalent circuits are obtained based on the electro mechanical equivalent circuits the resonance frequency equations and the expressions of angular and radial displacement amplitude magnifications are derived and the resonance frequencies and magnifications are solved by analytical method the relationships between torsional and radial resonance frequencies and geometrical dimensions are discussed and the relationships between angular and radial displacement amplitude magnifications and the ratio of outer radius over inner radius are analyzed modal shapes are analyzed by finite element method ansys it is shown that the values calculated by using the theory of this paper are in good agreement with the results simulated by ansys the method can serve as benchmark values for researchers to validate other variable thickness thin annular plates

global stability of an sir epidemic model with constant infectious period in this paper we derive and study an sir epidemic model with constant infectious period which is incorporated as a time delay both trivial and endemic equilibrium are found and their stability is investigated using lyapunov functional approach sufficient conditions for global stability of endemic equilibrium is obtained

transverse vibration of annular circular and elliptic plates using the characteristic orthogonal polynomials in two dimensions abstract characteristic orthogonal polynomials in two variables have been generated over the annular region occupied by a circular or elliptic plate satisfying the essential boundary conditions these are used to express the displacement in the transverse vibration of the plate the rayleigh ritz method is then applied to study the fundamental mode of vibration comparison has been made with the known results for circular annular plates in some cases the results for the elliptic annular plate are entirely new and are not available elsewhere all the results are summarized in tables covering various combinations of the boundary conditions

dynamics of a discretized sir epidemic model with pulse vaccination and time delay we derive a discretized sir epidemic model with pulse vaccination and time delay from the original continuous model the sufficient conditions for global attractivity of an infection free periodic solution and permanence of our model are obtained improving discretization our results are corresponding to those in the original continuous model

hybrid stabilization and synchronization of nonlinear systems with unbounded delays the stabilization of nonlinear systems with bounded and unbounded time delays via hybrid control is studied we investigate and identify switching rules for which stabilization can be verified a priori when this approach is inadequate stabilizing state dependent switching rules are constructed this method is based on partitioning the state space into switching regions unwanted physical behavior such as chattering and zeno behavior is avoided sufficient conditions are established using razumikhin like theorems the theoretical results provide insight into how hybrid control strategies can be constructed to synchronize a class of nonlinear systems with unbounded delay the findings are illustrated through numerical simulations

frequency constants for transverse vibration of annular disks frequency constants for the transverse vibration of thin annular disks are presented all nine combinations of the boundary conditions free simply supported and clamped are included for poisson s ratios of 0 0 0 3 and 0 5 many of these cases have been treated earlier in the literature but with occasional significant error consequently several tests of the validity of the present solutions are described

the sound power of an individual mode of a clamped free annular plate abstract the main aim of this study is an analysis of sound radiation of some clamped free and free clamped annular plates the plates are embedded in some infinite perfectly rigid baffles and vibrate with the free field condition satisfied the kirchhoff love linear theory of a perfectly elastic plate is used to solve the plates equations of motion the sound pressure at the plates surfaces is expressed by its hankel transform the closed path integral technique known from the literature and the stationary phase method are used to find the standardized active and reactive sound power of an individual mode in the form of some high frequency asymptotic formulae useful for some highly efficient engineering computations their non oscillating and oscillating parts have been separated it is assumed that the vibration and sound radiation are axisymmetric and time harmonic low fluid loading is also assumed the complex sound power of an individual mode forms the basis for computing the total sound power of some excited and damped vibrations in the fluid the total sound power is not discussed in this study

on the polygonal membrane with a circular core the purpose of the present paper is two fold first we study in detail the asymptotic properties where the center core shrinks to a point ie the membrane is pinned at the center second we show that the point match method yields results that differ considerably from those of laura et al especially when the fixed center core is large

an epidemic model of a vector borne disease with direct transmission and time delay abstract this paper considers an epidemic model of a vector borne disease which has direct mode of transmission in addition to the vector mediated transmission the incidence term is assumed to be of the bilinear mass action form we include both a baseline ode version of the model and a differential delay model with a discrete time delay the ode model shows that the dynamics is completely determined by the basic reproduction number r 0 if r 0 1 the disease free equilibrium is globally stable and the disease dies out if r 0 1 a unique endemic equilibrium exists and is locally asymptotically stable in the interior of the feasible region the delay in the differential delay model accounts for the incubation time the vectors need to become infectious we study the effect of that delay on the stability of the equilibria we show that the introduction of a time delay in the host to vector transmission term can destabilize the system and periodic solutions can arise through hopf bifurcation

backward bifurcation of an epidemic model with saturated treatment function an epidemic model with saturated incidence rate and saturated treatment function is studied here the treatment function adopts a continuous and differentiable function which can describe the effect of delayed treatment when the number of infected individuals is getting larger and the medical condition is limited the global dynamics of the model indicate that the basic reproduction number being the unity is a strict threshold for disease eradication when such effect is weak however it is shown that a backward bifurcation will take place when this delayed effect for treatment is strong therefore driving the basic reproduction number below the unity is not enough to eradicate the disease and a critical value at the turning point is deduced as a new threshold some sufficient conditions for the disease free equilibrium and the endemic equilibrium being globally asymptotically stable are also obtained mathematical results in this paper suggest that giving the patients timely treatment improving the cure efficiency and decreasing the infective coefficient are all valid methods for the control of disease

global analysis of an infection age model with a class of nonlinear incidence rates abstract sir infection age models with a very general class of nonlinear incidence rates f s j are investigated we give a necessary and sufficient condition for global asymptotic stability of the free equilibrium related to the basic reproduction number furthermore additional conditions allow us to prove an exponential stability of this disease free equilibrium finally by using a lyapunov functional we show the global asymptotic stability of the endemic equilibrium whenever it exists

blind wideband spatio temporal filtering based on higher order cyclostationarity properties in this paper a new method for blind minimum mean square error mmse spatio temporal signal filtering is proposed to obtain a blind version of the mmse filter the proposed method utilizes the signal selectivity property of the higher order cyclostationary statistics hocs exhibited by the signal of interest an accurate estimate of the transfer function of the mmse filter is obtained also in the presence of strong frequency overlapped interfering signals which would render standard stationarity based techniques ineffective the method is useful when the desired signal cannot be accurately extracted by exploiting its second order cyclostationarity properties because they are too weak and or they are shared by the interference and noise signals as well the performance analysis which is carried out by computer simulations in the case of quadrature amplitude modulated qam modulated signals with partially overlapping bands substantiates the effectiveness of the proposed method

determination of natural frequencies of a thick spinning annular disk using a numerical rayleigh ritz s trial function consideration is given in this paper to the problem of a thick spinning annular disk constrained at its inner radius mindlin s transverse shear deformation and rotary inertia terms are included in the eigenvalue formulation in the modified rayleigh ritz method used here the admissible or trial functions are developed numerically by an iterative scheme so that all the forced as well as natural boundary conditions are fully satisfied the natural frequencies for different mode shapes of the disk have been computed and are presented in a nondimensional form as a function of rotating speed

a general approximate solution of the problem of free vibrations of annular plates of stepped thickness abstract an approximate solution to the title problem is proposed for the case in which the inner boundary of the circular plate is free and the outer edge is elastically restrained against rotation the displacement amplitude is approximated by means of a superposition of simple polynomial co ordinate functions which satisfy identically the boundary conditions at the outer edge only and which yield excellent accuracy in the case of simply connected circular plates the optimized rayleigh ritz method is then used to generate the frequency determinant minimizing the eigenvalues with respect to an exponential parameter contained in each polynomial co ordinate function a comparison with eigenvalues obtained using a finite element solution is also presented and good agreement is shown to exist

multiple epidemic waves in delayed susceptible infected recovered models on complex networks we consider a delayed susceptible infected recovered epidemic model on an uncorrelated complex network and address the effect of time lag on the shape and multiple waves of epidemic curves we show that when the transmission rate is above a threshold a large delay can cause multiple waves with larger amplitudes in the second and subsequent waves

analysis of an improved epidemic model with stochastic disease transmission abstract this paper proposes an improved logistic epidemic model and carries out the complete parameters analysis of asymptotic behavior of infectious diseases some interesting details such as the threshold value of outbreak of epidemics and critical states of disease spread are derived the mean and variance of proportion of infected population are given explicitly the results show that our model is more reasonable and applicable to describe the real situation especially p 1 2 might be considered as the alarm for relate institutions to make effective policies to prevent and control some epidemics