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排序方式: 共有100条查询结果,搜索用时 31 毫秒
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基于滑动Kriging插值的MLPG法求解结构非耦合热应力问题 总被引:3,自引:1,他引:2
将基于滑动Kriging插值的无网格局部Petrov-Galerkin(MLPG)法用来求解二维结构非耦合热应力问题,首先进行瞬态热传导的求解,然后再通过顺序耦合法将不同时刻节点温度作为附加体力项施加到应力分析中.瞬态温度场和非耦合热应力分析通过加权余量法来离散,同时用Heaviside分段函数作为局部弱形式的权函数.由于滑动Kriging插值构造的形函数满足Kroneckerδ函数的性质,因此方便了本质边界条件的施加.刚度矩阵形成过程中只涉及到边界积分而没有涉及到区域积分,因此可以减少计算工作量,最后通过两个数值算例来验证本文方法的有效性. 相似文献
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Bert Bettonvil Enrique del Castillo Jack P.C. Kleijnen 《European Journal of Operational Research》2009
This article studies simulation-based optimization with multiple outputs. It assumes that the simulation model has one random objective function and must satisfy given constraints on the other random outputs. It presents a statistical procedure for testing whether a specific input combination (proposed by some optimization heuristic) satisfies the Karush–Kuhn–Tucker (KKT) first-order optimality conditions. The article focuses on “expensive” simulations, which have small sample sizes. The article applies the classic t test to check whether the specific input combination is feasible, and whether any constraints are binding; next, it applies bootstrapping (resampling) to test the estimated gradients in the KKT conditions. The new methodology is applied to three examples, which gives encouraging empirical results. 相似文献
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结构优化中的建模方法概述 总被引:6,自引:0,他引:6
建立优化模型是结构优化前的最佳选择. 由于工程实际问题的复杂性, 很难建立显式表
达的模型, 即使少数问题能够建立显式表达的模型, 也难以求解. 因此需要借助近似方法建
立模型, 为了便于求解或提高求解效率, 通常还要对模型进行变换. 文中列举了结构优化中
常用的近似建模方法, 并根据建立近似显式的途径和敏度分析的方法对其进行分类, 详细介
绍了近几年来广泛应用的样本点构造方法, 然后描述了它们在结构优化中的应用和具体实现
过程, 分析了它们的优缺点和应用范围, 指出了结构优化建模方法今后的发展方向. 相似文献
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In order to produce an accurate noise map of a city or a region, it is necessary to make noise measurements at certain locations and these measurements must be modeled with the most suitable mathematical algorithm. A homogeneous and representative distribution of the noise measurement points is the first key factor in the production of sound noise maps. The second key element is the calculation of the noise values of gridding points based on noise measurement points according to the selected mathematical calculation method and the generation of maps according to these gridding points. In this study, a noise map of the Isparta city center and its periphery was produced using inverse distance weighted (IDW), Kriging and multiquadric interpolation methods with different parameters and four grid resolution. Then, the influence of parameter selection for each method was investigated in themself by taking into account grid resolution, namely 10 ∗ 10 m, 50 ∗ 50 m, 100 ∗ 100 m and 200 ∗ 200 m, and the performance of three method with 50 ∗ 50 m grid resolution were compared with each other. In addition, the noise mapping of the city of Isparta were produced by Kriging method with respect to maximum, average and minimum noise data and they were evaluated by considering the national environmental noise thresholds. 相似文献
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基于Kriging模型的汽轮机基础动力优化设计 总被引:3,自引:0,他引:3
随着汽轮机容量的增加和核电站的迅速发展,汽轮机基础动力优化设计已经成为世界前沿的研究课题.本文提出一种基于Kriging模型的有效优化方法,用以求解上述动力优化设计问题.该问题的优化模型是在汽轮机基础框架重量约束条件下,优化汽轮机基础中柱的位置和粱、柱的截面面积,使基础振动的最大幅值最小化.Kriging模型用于建立基础振动的最大动位移幅值与设计变量间的近似函数关系,从而避免了优化迭代中灵敏度分析.开发了动力分析程序,作为黑箱用于动力响应分析.算例结果表明,本文方法在效率和稳定性上优于序列线性规划方法. 相似文献
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For structural systems with both epistemic and aleatory uncertainties, the effect of epistemic uncertainty on failure probability is measured by the variance based sensitivity analysis, which generally needs a “triple-loop” crude sampling procedure to solve and is time consuming. Thus, the Kriging method is employed to avoid the complex sampling procedure and improve the computational efficiency. By utilizing the Kriging predictor model, the conditional expectation of failure probability on the given epistemic uncertainty can be calculated efficiently. Compared with the Sobol’s method, the proposed one can ensure reasonable accuracy of results but with lower computational cost. Three examples are employed to demonstrate the reasonability and efficiency of the proposed method. 相似文献
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Michael L. Stein 《Journal of computational and graphical statistics》2013,22(4):866-885
Compactly supported autocovariance functions reduce computations needed for estimation and prediction under Gaussian process models, which are commonly used to model spatial and spatial-temporal data. A critical issue in using such models is the loss in statistical efficiency caused when the true autocovariance function is not compactly supported. Theoretical results indicate the value of specifying the local behavior of the process correctly. One way to obtain a compactly supported autocovariance function that has similar local behavior to an autocovariance function K of interest is to multiply K by some smooth compactly supported autocovariance function, which is called covariance tapering. This work extends previous theoretical results showing that covariance tapering has some asymptotic optimality properties as the number of observations in a fixed and bounded domain increases. However, numerical experiments show that for purposes of parameter estimation, covariance tapering often does not work as well as the simple alternative of breaking the observations into blocks and ignoring dependence across blocks. When covariance tapering is used for spatial prediction, predictions near the boundary of the observation domain are affected most. This article proposes an approach to modifying the taper to ameliorate this edge effect. In addition, a justification for a specific approach to carrying out conditional simulations based on tapered covariances is given. Supplementary materials for this article are available online. 相似文献