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基于影响因素可靠度的改进OD反推算法 被引量:5
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作者 邓亚娟 陈小鸿 《中国公路学报》 EI CAS CSCD 北大核心 2007年第3期103-108,共6页
通过4组测试方案,采用敏感性分析、数理统计分析方法分析了先验矩阵总量、分布结构以及观测OD对数量对OD反推结果的影响程度;提出了考虑先验矩阵和观测路段流量可靠度的改进极大熵算法。研究结果表明:先验矩阵总量基本不影响OD反推结果... 通过4组测试方案,采用敏感性分析、数理统计分析方法分析了先验矩阵总量、分布结构以及观测OD对数量对OD反推结果的影响程度;提出了考虑先验矩阵和观测路段流量可靠度的改进极大熵算法。研究结果表明:先验矩阵总量基本不影响OD反推结果;先验矩阵分布结构决定着反推结果的准确性;OD反推要求观测路段包含所有OD对,且OD对数量越多,反推结果越准确,基本不会出现OD信息冗余;在反推过程中考虑先验矩阵和观测路段流量可靠度,有助于提高反推精度。 展开更多
关键词 交通工程 od反推算 理论分析 先验矩阵 观测流量 贡献度 可靠度
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OD反推中调查路段选取方法研究 被引量:5
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作者 陈宗军 李克平 孙剑 《交通与计算机》 2007年第1期104-106,112,共4页
以OD反推中的调查路段选取原则为基础,提出了一种在有先验OD矩阵前提下,用于OD反推的调查路段选取实用方法——OD期望线截取法;借助交通规划软件Visum,验证了此方法符合调查路段选取的4个基本准则。以杭州市中心区道路网为例,对比最大... 以OD反推中的调查路段选取原则为基础,提出了一种在有先验OD矩阵前提下,用于OD反推的调查路段选取实用方法——OD期望线截取法;借助交通规划软件Visum,验证了此方法符合调查路段选取的4个基本准则。以杭州市中心区道路网为例,对比最大流量路段法验证了OD期望线截取法的有效性。结果表明在同样的调查路段数下,OD期望线截取法的GEH值由5.99下降到5.02,最大50位OD覆盖率由64%上升到72%。 展开更多
关键词 od反推 调查路段 VISUM od期望线截取
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基于仿真ODS法的某车型后门锁扣动刚度优化设计
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作者 曾维和 张德彬 +2 位作者 吴强 苟黎刚 管迪 《汽车实用技术》 2020年第10期54-57,共4页
文章基于NASTRAN对某SUV车型后门锁扣动刚度进行仿真分析,根据动刚度仿真结果对原有方案提出了两种轻量化构思方案,然后对轻量化方案的动刚度进行验证比较,优选出综合性能更优越的轻量化方案;最后对优选的轻量化方案进行ODS仿真分析,根... 文章基于NASTRAN对某SUV车型后门锁扣动刚度进行仿真分析,根据动刚度仿真结果对原有方案提出了两种轻量化构思方案,然后对轻量化方案的动刚度进行验证比较,优选出综合性能更优越的轻量化方案;最后对优选的轻量化方案进行ODS仿真分析,根据ODS分析结果对锁扣安装结构优化设计,既提升了动刚度性能又实现减重降本的目标。研究结果表明:与初始方案比,优化后的锁扣安装结构能实现单侧减重0.65kg,轻量化比例高达33.2%,轻量化降本效果显著。优化方案后门锁扣X/Y/Z向动刚度均有不同程度增加,动刚度水平提升至与初始方案基本相当。 展开更多
关键词 后门锁扣 动刚度 odS仿真 结构优化
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京杭运河黄河以北山东段航道货运量预测
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作者 张楠 陈乾阳 张毅濠 《山东交通科技》 2024年第1期145-148,共4页
根据京杭运河黄河以北山东段的航道区位特点,提出航道货运量组成分为境内货运量和过境货运量;根据腹地经济和全社会货运量发展情况,通过回归模型、弹性系数等数学模型计算境内货运量;根据综合交通运输通道的货运量发展情况,预测过境货运... 根据京杭运河黄河以北山东段的航道区位特点,提出航道货运量组成分为境内货运量和过境货运量;根据腹地经济和全社会货运量发展情况,通过回归模型、弹性系数等数学模型计算境内货运量;根据综合交通运输通道的货运量发展情况,预测过境货运量;并通过设定京杭运河沿线省市之间的多种运输情景,量化分析货运的经济优势。结果表明:京杭运河黄河以北山东段2035年货运量预测值为2900万t,2050年货运量预测值为5400万t,相比较于铁路、公路等综合交通运输方式,京杭运河的货运成本可降低10%以上,经济优势显著,发展前景广阔。 展开更多
关键词 运输需求 货运量 od法 京杭运河 运输费用 运输效率
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Quantum Dynamics Study on D+OD+ Reaction: Competition between Exchange and Abstraction Channels
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作者 许文武 张佩宇 何国钟 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2013年第1期73-76,I0004,共5页
Quantum dynamics for the D+OD+ reaction at the collision energy range of 0.0-1.0 eV was studied on an accurate ab initio potential energy surface. Both of the endothermic abstraction (D+OD+-→O++D2) and thermo... Quantum dynamics for the D+OD+ reaction at the collision energy range of 0.0-1.0 eV was studied on an accurate ab initio potential energy surface. Both of the endothermic abstraction (D+OD+-→O++D2) and thermoneutral exchange (D+OD+--*D+OD+) channels were investigated from the same set of time-dependent quantum wave packets method under cen- trifugal sudden approximation. The reaction probability dependence with collision energy, the integral cross sections, and the thermal rate constant of the both channels are calculated. It is found that there is a convex structure in the reaction path of the exchange reaction. The calculated time evolution of the wave packet distribution at J=0 clearly indicates that the convex structure significantly influences the dynamics of the exchange and abstraction channels of title reaction. 展开更多
关键词 Time-dependent quantum wave packet method Potential energy surface D+od reaction
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A Superlinerly Convergent ODE-type Trust Region Algorithm for LC^1 Optimization Problems 被引量:5
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作者 OUYi-gui HOUDing-pi 《Chinese Quarterly Journal of Mathematics》 CSCD 2003年第2期140-145,共6页
In this paper, a new trust region algorithm for unconstrained LC1 optimization problems is given. Compare with those existing trust regiion methods, this algorithm has a different feature: it obtains a stepsize at eac... In this paper, a new trust region algorithm for unconstrained LC1 optimization problems is given. Compare with those existing trust regiion methods, this algorithm has a different feature: it obtains a stepsize at each iteration not by soloving a quadratic subproblem with a trust region bound, but by solving a system of linear equations. Thus it reduces computational complexity and improves computation efficiency. It is proven that this algorithm is globally convergent and locally superlinear under some conditions. 展开更多
关键词 LC1 optimization odE methods trust region algorithm superlinear convergence
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规划网络路段交通量预测模型研究
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作者 沈文 《东北公路》 北大核心 2000年第3期36-38,共3页
交通量预测是公路网络规划过程中的一项重要工作 ,本文在传统的路段交通量预测方法的基础上 ,介绍了路段交通量 OD模型法 ,根据实际道路网的形状 ,通过使路段交通量的预测值与观测值一致来进行模型推算 ,从而计算出规划网络上的交通量... 交通量预测是公路网络规划过程中的一项重要工作 ,本文在传统的路段交通量预测方法的基础上 ,介绍了路段交通量 OD模型法 ,根据实际道路网的形状 ,通过使路段交通量的预测值与观测值一致来进行模型推算 ,从而计算出规划网络上的交通量。与现有方法相比 。 展开更多
关键词 交通量预测模型 公路网络规划 od模型
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Trust Region Algorithm for a Class of Nonlinear Complementarity Problem 被引量:3
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作者 OU Yi-gui 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2007年第4期558-566,共9页
In this paper, an ODE-type trust region algorithm for solving a class of nonlinear complementarity problems is proposed. A feature of this algorithm is that only the solution of linear systems of equations is required... In this paper, an ODE-type trust region algorithm for solving a class of nonlinear complementarity problems is proposed. A feature of this algorithm is that only the solution of linear systems of equations is required at each iteration, thus avoiding the need for solving a quadratic subproblem with a trust region bound. Under some conditions, it is proven that this algorithm is globally and locally superlinear convergent. The limited numerical examples show its efficiency. 展开更多
关键词 nonlinear complementarity problems odE methods trust region methods Fischer-Burmeister function
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Exact Solutions to a Combined sinh-cosh-Gordon Equation 被引量:1
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作者 魏龙 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第10期599-602,共4页
Based on a transformed Painlev~ property and the variable separated ODE method, a function transfor- mation method is proposed to search for exact solutions of some partial differential equations (PDEs) with hyperbo... Based on a transformed Painlev~ property and the variable separated ODE method, a function transfor- mation method is proposed to search for exact solutions of some partial differential equations (PDEs) with hyperbolic or exponential functions. This approach provides a more systematical and convenient handling of the solution process of this kind of nonlinear equations. Its key point is to eradicate the hyperbolic or exponential terms by a transformed Painleve property and reduce the given PDEs to a variable-coefficient the resulting equations by some methods. As an application, are formally derived. ordinary differential equations, then we seek for solutions to exact solutions for the combined sinh-cosh-Gordon equation 展开更多
关键词 function transformation method variable separated odE method combined sinh-cosh-Gordonequation
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Exact Solutions for Fractional Differential-Difference Equations by an Extended Riccati Sub-ODE Method 被引量:2
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作者 冯青华 《Communications in Theoretical Physics》 SCIE CAS CSCD 2013年第5期521-527,共7页
In this paper, an extended Riccati sub-ODE method is proposed to establish new exact solutions for fractional differential-difference equations in the sense of modified Riemann-Liouville derivative. By a fractional co... In this paper, an extended Riccati sub-ODE method is proposed to establish new exact solutions for fractional differential-difference equations in the sense of modified Riemann-Liouville derivative. By a fractional complex transformation, a given fractional differential-difference equation can be turned into another differential-difference equation of integer order. The validity of the method is illustrated by applying it to solve the fractional Hybrid lattice equation and the fractional relativistic Toda lattice system. As a result, some new exact solutions including hyperbolic function solutions, trigonometric function solutions and rational solutions are established. 展开更多
关键词 fractional differential-difference equations exact solutions Riccati sub-odE method fractional complex transformation
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Efficient implementation of the Barnes-Hut octree algorithm for Monte Carlo simulations of charged systems 被引量:1
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作者 GAN ZeCheng XU ZhenLi 《Science China Mathematics》 SCIE 2014年第7期1331-1340,共10页
Computer simulation with Monte Carlo is an important tool to investigate the function and equilibrium properties of many biological and soft matter materials solvable in solvents.The appropriate treatment of long-rang... Computer simulation with Monte Carlo is an important tool to investigate the function and equilibrium properties of many biological and soft matter materials solvable in solvents.The appropriate treatment of long-range electrostatic interaction is essential for these charged systems,but remains a challenging problem for large-scale simulations.We develop an efficient Barnes-Hut treecode algorithm for electrostatic evaluation in Monte Carlo simulations of Coulomb many-body systems.The algorithm is based on a divide-and-conquer strategy and fast update of the octree data structure in each trial move through a local adjustment procedure.We test the accuracy of the tree algorithm,and use it to perform computer simulations of electric double layer near a spherical interface.It is shown that the computational cost of the Monte Carlo method with treecode acceleration scales as log N in each move.For a typical system with ten thousand particles,by using the new algorithm,the speed has been improved by two orders of magnitude from the direct summation. 展开更多
关键词 ELECTROSTATICS Monte Carlo fast algorithms OCTREE colloidal interfaces
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SIGNAL ESTIMATION WITH BINARY-VALUED SENSORS
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作者 Leyi WANG Gang George YIN +1 位作者 Chanying LI Weixing ZHENG 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2010年第3期622-639,共18页
This paper introduces several algorithms for signal estimation using binary-valued outputsensing.The main idea is derived from the empirical measure approach for quantized identification,which has been shown to be con... This paper introduces several algorithms for signal estimation using binary-valued outputsensing.The main idea is derived from the empirical measure approach for quantized identification,which has been shown to be convergent and asymptotically efficient when the unknown parametersare constants.Signal estimation under binary-valued observations must take into consideration oftime varying variables.Typical empirical measure based algorithms are modified with exponentialweighting and threshold adaptation to accommodate time-varying natures of the signals.Without anyinformation on signal generators,the authors establish estimation algorithms,interaction between noisereduction by averaging and signal tracking,convergence rates,and asymptotic efficiency.A thresholdadaptation algorithm is introduced.Its convergence and convergence rates are analyzed by using theODE method for stochastic approximation problems. 展开更多
关键词 IDENTIFICATION signal estimation.
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