FLIP AND N-S BIFURCATION BEHAVIOR OF A PREDATOR-PREY MODEL WITH PIECEWISE CONSTANT ARGUMENTS AND TIME DELAY

In this paper, the stability and bifurcation behaviors of a predator-prey model with the piecewise constant arguments and time delay are investigated. Technical approach is fully based on Jury criterion and bifurcation theory. The interesting point is that the model will produce two different branches by limiting branch parameters of different intervals. Besides, image simulation is also given.

ASYMPTOTIC EQUIVALENCE OF ALTERNATELY ADVANCED AND DELAYED DIFFERENTIAL SYSTEMS WITH PIECEWISE CONSTANT GENERALIZED ARGUMENTS

In this paper, we investigate the existence, uniqueness and the asymptotic equiv- alence of a linear system and a perturbed system of differential equations with piecewise alternately advanced and retarded argument of generalized type （DEPCAG）. This is based in the study of an equivalent integral equation with Cauchy and Green matrices type and in a solution of a DEPCAG integral inequality of Gronwall type. Several examples are also given to show the feasibility of results.

ON THE LASOTA-WAZEWSKA MODEL WITH PIECEWISE CONSTANT ARGUMENT

In this article, a delay differential equation with piecewise constant argument is considered; the existence and global attractivity condition of almost periodic solution and quasi-periodic solution are obtained.

Asymptotically Antiperiodic Solutions for a Nonlinear Differential Equation with Piecewise Constant Argument in a Banach Space

In this paper, we give sufficient conditions for the existence and uniqueness of asymptotically w-antiperiodic solutions for a nonlinear differential equation with piecewise constant argument in a Banach space when w is an integer. This is done using the Banach fixed point theorem. An example involving the heat operator is discussed as an illustration of the theory.

3D Multiphase Piecewise Constant Level Set Method Based on Graph Cut Minimization

Segmentation of three-dimensional(3D) complicated structures is of great importance for many real applications.In this work we combine graph cut minimization method with a variant of the level set idea for 3D segmentation based on the Mumford-Shah model.Compared with the traditional approach for solving the Euler-Lagrange equation we do not need to solve any partial differential equations.Instead,the minimum cut on a special designed graph need to be computed.The method is tested on data with complicated structures.It is rather stable with respect to initial value and the algorithm is nearly parameter free.Experiments show that it can solve large problems much faster than traditional approaches.

An Improved Mumford-Shah Model and Its Applications to Image Processing with the Piecewise Constant Level Set Method

为快分割并且降噪，提高 penalization 学期的古典 Mumford-Shah (MS ) 模型需要，即增加 penalization 参数，它导致目标的渐渐的消失。在这份报纸，我们建议一个改进 Mumford-Shah (IMS ) 模型避免现象，并且采用 piecewise 常数水平集合方法(PCLSM ) 和坡度降下方法解决最小化问题。数字实验被给显示出新模型和算法的效率和优点。

L0 Regularization for the Estimation of Piecewise Constant Hazard Rates in Survival Analysis

In a survival analysis context, we suggest a new method to estimate the piecewise constant hazard rate model. The method provides an automatic procedure to find the number and location of cut points and to estimate the hazard on each cut interval. Estimation is performed through a penalized likelihood using an adaptive ridge procedure. A bootstrap procedure is proposed in order to derive valid statistical inference taking both into account the variability of the estimate and the variability in the choice of the cut points. The new method is applied both to simulated data and to the Mayo Clinic trial on primary biliary cirrhosis. The algorithm implementation is seen to work well and to be of practical relevance.

Analytical Approach to Differential Equations with Piecewise Continuous Arguments via Modified Piecewise Variational Iteration Method

In the present article, we apply the modified piecewise variational iteration method to obtain the approximate analytical solutions of the differential equations with piecewise continuous arguments. This technique provides a sequence of functions which converges to the exact solution of the problem. Moreover, this method reduces the volume of calculations because it does not need discretization of the variables, linearization or small perturbations. The results seem to show that the method is very reliable and convenient for solving such equations.

The piecewise constant method in gait design through optimization

The objective of this paper is to introduce the piecewise constant method in gait design of a planar,under actuated,five-link biped robot model and to discuss the advantages and disadvantages.The piecewise constant method transforms the dynamic optimal control problem into a static problem.

一类带有分段常数变元的线性时滞微分方程的振动判据

针对一类带有分段变元的线性时滞微分方程,在系数缓慢变化的情形下,利用Bolzano-Weierstrass定理,建立判定其振动性的充分条件,将已有的下极限型条件改进为上极限型条件,进而可以判定部分原先所不能判定的方程的振动性,并采用2个例子证明其有效性。

BDS/GPS对流层延迟估计及对精密单点定位的影响

针对对流层湿延迟参数估计及水平梯度处理策略对精密单点定位影响的问题,以9个多系统实验网实测数据为基础,设计了6种对流层延迟处理方案并进行实验.实验结果表明,观测时长在8 h时段内,BDS/GPS定位模式下,对流层延迟的水平梯度处理不宜采用随机游走模型;采用随机游走估算对流层湿延迟参数,且不估算或使用分段常数处理水平梯度的策略相对占优.动静态精密单点定位结果显示,BDS/GPS采用分段常数或随机游走进行对流层湿延迟参数估算和分段常数处理水平梯度的策略相对占优,采用随机游走处理水平梯度的策略稍弱.总体而言,BDS较GPS估算的对流层延迟及定位精度稍弱;海洋周边6种方案解算结果差异较内陆站大.静态精密单点定位模式下,随着观测时长的增加,6种方案定位误差趋势趋于一致,误差大小基本在2 cm内,观测时长大于12 h时,随机游走估算对流层湿延迟参数和不考虑水平梯度的处理策略整体较优.

A Set of Almost Automorphic Functions and Applications

For a set S of real numbers, we introduce the concept of S-almost automorphic functions valued in a Banach space. It generalizes in particular the space of Z-almost automorphic functions. Considering the space of S-almost automorphic functions, we give sufficient conditions of the existence and uniqueness of almost automorphic solutions of a differential equation with a piecewise constant argument of generalized type. This is done using the Banach fixed point theorem.

具有分段常数参数的Cohen-Grossberg神经网络的全局指数稳定

主要研究了具有分段常数参数的Cohen-Grossberg神经网络的全局指数稳定性,得到了保证平衡点的存在唯一性的充分条件,通过线性不等式方法,并构造适当的李雅普诺夫泛函,提出了系统的平衡点的全局指数稳定性的判据,最后给了一个数值例子验证所得结果的有效性。

Determination of pKa values of alendronate sodium in aqueous solution by piecewise linear regression based on acid-base potentiometric titration

As a mono-sodium salt form of alendronic acid,alendronate sodium presents multi-level ionization for the dissociation of its four hydroxyl groups.The dissociation constants of alendronate sodium were determined in this work by studying the piecewise linear relationship between volume of titrant and p H value based on acidbase potentiometric titration reaction.The distribution curves of alendronate sodium were drawn according to the determined p Ka values.There were 4 dissociation constants(pKa_1=2.43,pKa_2=7.55,pKa_3=10.80,pKa_4=11.99,respectively) of alendronate sodium,and 12 existing forms,of which 4 could be ignored,existing in different p H environments.

MULTIDIMENSIONAL MULTI-KNOTS PIECEWISE LINEAR SPECTRAL SEQUENCES

Motivated by representing multidimensional periodic nonlinear and non-stationary signals （functions）, we study a class of orthonormal exponential basis for L2（Id） with I ：= [0, 1）, whose exponential parts are piecewise linear spectral sequences with p-knots. It is widely applied in time-frequency analysis.

Continuous Piecewise Linear Approximation of BV Function

Nonlinear approximation is widely used in signal processing. Real-life signals can be modeled as functions of bounded variation. Thus the variable knot of approximating function could be self- adaptively chosen by balancing the total variation of the target function. In this paper, we adopt continuous piecewise linear approximation instead of the existing piecewise constants approximation. The results of experiments show that this new method is superior to the old one.

基于分段二次流变模型的泥石流流速垂向分布

泥石流流速垂向分布是泥石流动力学的核心研究内容之一,它关系到泥石流堆积、运移、冲击力、运动摩阻等重要工程设计参数的计算。本文对二次流变模型进行分段处理,建立泥石流流速垂向分布理论计算公式,用17组试验数据对模型进行验证。结果表明:分段流变模型能较好地拟合试验数据;基于试验数据,建立了卡门常数与含沙量之间的关系,给出了流速为0的位置与中值粒径和含沙量的关系。

Existence of almost periodic solutions of neutral differential equations with piecewise constant argument

Based on the properties on almost periodic sequence, it is proved that the almost periodic solutions for a class of neutral differential equations with piecewise constant argument exist.

Pseudo almost periodic solutions for the systems of differential equations with piecewise constant argument [t]

In this paper, we investigate the existence and uniqueness of new almost periodic type solutions, so-called pseudo almost periodic solutions for the systems of differential equations with piecewise constant argument by means of introducing the notion of pseudo almost periodic vector sequences.