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交通事故分析模型方程组病态性的处理 被引量:2
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作者 张建 蒙彦宇 《北华大学学报(自然科学版)》 CAS 2006年第5期468-473,共6页
为了解决汽车碰撞事故再现模型病态性的问题,采用汽车碰撞模拟法分析了参数变化对模型病态性的影响.以矩阵扰动理论为基础分析了模型病态性的本质,给出了参数扰动条件下模型解的相对误差数学表达式,提出了如何处理原始方程组解决模... 为了解决汽车碰撞事故再现模型病态性的问题,采用汽车碰撞模拟法分析了参数变化对模型病态性的影响.以矩阵扰动理论为基础分析了模型病态性的本质,给出了参数扰动条件下模型解的相对误差数学表达式,提出了如何处理原始方程组解决模型病态性的方法,通过计算实例证明了该方法的有效性。 展开更多
关键词 交通事故 模型病态性 事故分析模型 条件数
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病态乘性误差模型的加权最小二乘正则化迭代解法及精度评定 被引量:5
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作者 王乐洋 陈涛 邹传义 《测绘学报》 EI CSCD 北大核心 2021年第5期589-599,共11页
针对乘性误差模型的病态问题,引入Tikhonov正则化方法,导出了病态乘性误差模型的加权最小二乘正则化解。顾及加权最小二乘正则化法在求解病态乘性误差模型时,参数估值与观测值之间存在复杂的非线性关系,本文利用一种无需求导、通过加权... 针对乘性误差模型的病态问题,引入Tikhonov正则化方法,导出了病态乘性误差模型的加权最小二乘正则化解。顾及加权最小二乘正则化法在求解病态乘性误差模型时,参数估值与观测值之间存在复杂的非线性关系,本文利用一种无需求导、通过加权的方式便能够计算非线性函数的均值和均方误差阵的比例对称采样的无迹变换(scaled unscented transformation,SUT)法,对病态乘性误差模型进行精度评定。模拟算例和真实算例结果表明,本文提出的加权最小二乘正则化迭代解法可以有效减弱模型的病态性,基于SUT法的精度评定方法能够得到比已有方法更为合理的精度信息,具有较强的适用性。 展开更多
关键词 病态误差模型 TIKHONOV正则化 L曲线法 精度评定 SUT法
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Existence for positive steady states of an eco-epidemiological model
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作者 王雅萍 陈文彦 《Journal of Southeast University(English Edition)》 EI CAS 2011年第1期119-122,共4页
An eco-epidemiological model with an epidemic in the predator and with a Holling type Ⅱ function is considered.A system with diffusion under the homogeneous Neumann boundary condition is studied.The existence for a p... An eco-epidemiological model with an epidemic in the predator and with a Holling type Ⅱ function is considered.A system with diffusion under the homogeneous Neumann boundary condition is studied.The existence for a positive solution of the corresponding steady state problem is mainly discussed.First,a prior estimates(positive upper and lower bounds) of the positive steady states of the reaction-diffusion system is given by the maximum principle and the Harnack inequation.Then,the non-existence of non-constant positive steady states by using the energy method is given.Finally,the existence of non-constant positive steady states is obtained by using the topological degree. 展开更多
关键词 eco-epidemiological model EXISTENCE positive steady states
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Epidemiological modeling of passive worm propagation on the P2P file-sharing network
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作者 Feng Chaosheng Qin Zhiguang +1 位作者 Laurissa Tokarchuk Muhammad Adeel 《High Technology Letters》 EI CAS 2011年第3期230-235,共6页
The peer-to-peer(P2P) file-sharing network as a vehicle of disseminating files has become very popular. The appearance of dozens of kinds of passive worms on this network has, however, made it unsecured. This proble... The peer-to-peer(P2P) file-sharing network as a vehicle of disseminating files has become very popular. The appearance of dozens of kinds of passive worms on this network has, however, made it unsecured. This problem has been paid attention and a few of models for passive worm propagation has been presented. Unfortunately, the dynamic properties of this network are ignored in these models. Given the fact, the characteristics of both this network and the passive worm are identified, and on this basis a new mathematical model of passive worm propagation on the P2P network is presented in applying epidemiology in this paper. Note that the dynamic properties of this network are considered in the presented model. The model has been validated by large scale simulation experiments, which demonstrates that the presented model may be used for analyzing the behaviors of passive worms and predicting the trend of their propagation. 展开更多
关键词 passive worms PROPAGATION modeling P2P networks FILE-SHARING simulation
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A NOVEL APPLICATION OF A CLASSICAL METHOD FOR CALCULATING THE BASIC REPRODUCTIVE NUMBER, Ro FOR A GENDER AND RISK STRUCTURED TRANSMISSION DYNAMIC MODEL OF HUMAN PAPILLOMAVIRUS INFECTION
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作者 KATY TOBIN CATHERINE COMISKEY 《International Journal of Biomathematics》 2013年第6期149-161,共13页
Mathematical models are increasingly being used in the evaluation of control strategies for infectious disease such as the vaccination program for the Human PapiUomavirus (HPV). Here, an ordinary differential equati... Mathematical models are increasingly being used in the evaluation of control strategies for infectious disease such as the vaccination program for the Human PapiUomavirus (HPV). Here, an ordinary differential equation (ODE) transmission dynamic model for HPV is presented and analyzed. Parameter values for a gender and risk structured model are estimated by calibrating the model around the known prevalence of infection. The effect on gender and risk sub-group prevalence induced by varying the epidemiological parameters are investigated. Finally, the outcomes of this model are applied using a classical mathematical method for calculating R0 in a heterogeneous mixing population. Estimates for R0 under various gender and mixing scenarios are presented. 展开更多
关键词 Transmission dynamic models HPV ODE SIR model R0
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