Fatigue life calculation by means of the cycle counting and spectral methods under multiaxial random loading

The paper contains a new algorithm for estimation of fatigue life in HCF regime under multiaxial random loading using spectral methods. Loading of Gaussian distribution and narrow‐ and broad‐band frequency spectra were assumed. Various characteristic states of multiaxial loading were considered. The equivalent stress history was determined with use of the failure criteria of multiaxial fatigue based on the critical plane. For determination of the critical plane position, the method of variance was applied. During simulation, the authors compared the results obtained by a spectral method in the frequency domain with those from the rain‐flow algorithm in the time domain. The paper also contains the results of fatigue tests for 18G2A structural steel subjected to bending and combined bending with torsion. The tests were performed in order to verify the proposed algorithms for determination of fatigue life. It has been shown that under multiaxial random loading results of fatigue life calculated according to the considered algorithms in frequency and time domains are well correlated with the results of experiments.     

基于离散泰勒级数的新型联想记忆系统

基于离散泰勒级数提出一种对任意阶多维函数可实现无差逼近的新型联想记忆系统，详细讨论了该系统的插值算法、训练规则及寻址机制，新型联想记忆系统相对于CMAC具有逼近精度更高、占用存储单元较少、学习速度较快等优点，该系统在信号处理、模式识别、过程建模及高精度实时智能控制等领域具有广泛的应用价值，仿真实例表明了系统的可行性与有效性。     

遗传-多点退火接力混合算法的应用

遗传-多点退火接力混合算法是先进行遗传算法操作,再接力使用模拟退火法操作的一种尝试。其关键在于遗传算法中变异的处理及退火中初始温度和降温值的处理。给出了该方法的基本过程和原型过程的数学描述,对算法中的罚因子,变异情况及温度值的选取进行了分析。通过具体实例的计算结果表明,将此方法用于非线性约束优化是可行的。     

基于Agent的遗传算法描述与演化模型研究

Agent是指具有智能的人或其它智能物.它具有自治、反响、推测、协作、自学习和相互学习等能力,本文基于Darwin自然进化论与Mendel遗传变异理论,给出Agent的遗传算法与演化模型.这些理论的提出,进一步丰富和完善了Agent的研究内容.     

OSPF路由协议及其实现算法

随着网络规模的不断扩大，路由器在沟通子网连接和实现信息交换方面的重要作用逐渐被人们所认知。介绍了OSPF(Open Shortest Path First)路由协议的特征、实现算法和工作原理等内容。OSPF已成为目前Internet广域网和Itranet企业网采用最多，应用最广泛的路由协议之一。OSPF路由协议是由IETF(Internet Engineering Task Force)IGP工作小组提出的，是一种基于SPF算法的路由协议。     

Mapping of Sahelian vegetation parameters from ERS scatterometer data with an evolution strategies algorithm

The West African Sahel rainfall regime is known for its spatio-temporal variability at different scales which has a strong impact on vegetation development. This study presents results of the combined use of a simple water balance model, a radiative transfer model and ERS scatterometer data to produce map of vegetation biomass and thus vegetation cover at a spatial resolution of 25 km. The backscattering coefficient measured by spaceborne wind scatterometers over Sahel shows a marked seasonality linked to the drastic changes of both soil and vegetation dielectric properties associated to the alternating dry and wet seasons. For lack of a direct observation, METEOSAT rainfall estimates are used to calculate temporal series of soil moisture with the help of a water balance model. This a priori information is used as input of the radiative transfer model that simulates the interaction between the radar wave and the surface components (soil and vegetation). Then, an inversion algorithm is applied to retrieve vegetation aerial mass from the ERS scatterometer data. Because of the nonlinear feature of the inverse problem to be solved, the inversion is performed using a global stochastic nonlinear inversion method. A good agreement is obtained between the inverse solutions and independent field measurements with mean and standard deviation of −54 and 130 kg of dry matter by hectare (kg DM/ha), respectively. The algorithm is then applied to a 350,000 km² area including the Malian Gourma and Seno region and a Sahelian part of Burkina Faso during two contrasted seasons (1999 and 2000). At the considered resolution, the obtained herbaceous mass maps show a global qualitative consistency (r²=0.71) with NDVI images acquired by the VEGETATION instrument.     

信息网格中具有动态变更适应性的元数据发布策略

信息源元数据的动态变更可能造成应用对信息源引用关系不一致，在不改应用程序的条件下，用户不能正确访问信息源。基于网格地址空间模型，使得应用程序通过虚拟层元数据，即应用领域元数据，来间接使用信息源元数据；当信息源元数据变更时，不是改应用程序而是通过调整信息源元数据和应用领域元数据之间的映射来保证应用对信息源引用关系的一致性，从元数据发布的角度出发，提出了一个具有动态适应性的元数据发布算法(Vega adaptive mapping)，通过此算法自动调整信息源元数据和应用领域元数据之间的映射；并将此算法相应的方法和现有的元数据发布方法进行了比较，比较结果表明此方法在适应元数据变更性方面具有一定的优越性。     

一种高效的视图维护算法

通过选择性算法将增量式视图维护和视图自维护有效地融合在一起．同时它还利用相关性算法对不相关更新进行过滤，可以有效地降低消息总数和数据的通信量，从而大大提高视图维护的效率，具有现实的应用意义．     

基于偏序关系的遗传算法求解多峰函数优化问题

该文设计了基于偏序关系的演化算法求解多峰函数优化问题新算法。并从偏序关系的性质出发,从理论上为该算法的收敛性提供了一定的依据,进而为其搜索操作提供了明确的方向,避免了演化搜索过程中的盲目性。     

应用于回归神经网络的基于梯度的典型算法的归纳与分析

首先给出了分层全回归神经网络的一个综合形式及其状态方程,然后归纳了几种典型的基于梯度的回归神经网络训练算法,描述了算法的具体步骤,并分析比较了算法特点及相互联系,最后指出对回归神经网络尤其是其训练算法研究存在的难点及研究重点。