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排序方式: 共有292条查询结果,搜索用时 15 毫秒
41.
Dynamic simulation of grain boundary migration in two dimensions requires the combined movement of grain boundaries and three-junctions. In this work, a method of dynamic simulation is described where the migration is broken down into two steps: I. The grain boundaries migrate with frozen threejunctions. II. The three-junctions are released in order to obtain equilibrium. In principle, the development of any initial two-dimensional grain-structure can be studied. The CPU-time and memory requirements increase with increasing number of grains. 相似文献
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介绍了霍尔传感器的优点和对其特性曲线进行拟合的必要性;对三次样条函数在霍尔传感器特性曲线拟合中的应用进行了理论分析,应用软件Matlab6.5结合实验数据对UGN3501U型传感器的UH—B曲线进行了拟合;给出了传感器拟合点减少的方案,这样,可以减少成本和工作量,但对相对误差影响不大。结果表明,原拟合的曲线与减少拟合点后的拟合曲线两者都很光滑、精度高且相对误差都很小,这种方法有很强的实用性和较高的理论价值。 相似文献
44.
Rosaria Lombardo 《Food quality and preference》2011,22(8):714-724
When the information given by a panel of judges on wine sensory characteristics is resumed in a three-way table, Y, and the objective is to extract knowledge from a chemical data-set, X, which has a predictive power for wine sensorial variables, the study of the relationships between chemical–physical variables and sensorial data sets is really complex. In this paper after resuming the information in Y, we propose to consider multivariate additive partial least squares via splines, recently presented in literature, to predict Y by X. 相似文献
45.
Wei-Hsin Chen Zong-Lin Tsai Min-Hsing Chang Siming You Pei-Chi Kuo 《International Journal of Hydrogen Energy》2021,46(31):16717-16733
For proton exchange membrane fuel cells (PEMFCs), the distribution of reactant streams in the reactor is critical to their efficiency. This study aims to investigate the optimal design of the inlet/outlet flow channel in the fuel cell stack with different geometric dimensions of the tube and intermediate zones (IZ). The tube-to-IZ length ratio, the IZ width, and the tube diameter are adjusted to optimize the geometric dimensions for the highest pressure uniformity. Four different methods, including the Taguchi method, analysis of variance (ANOVA), neural network (NN), and multiple adaptive regression splines (MARS), are used in the analyses. The results indicate the tube diameter is the most impactive one among the three factors to improve the pressure uniformity. The analysis suggests that the optimal geometric design is the tube-to-IZ length ratio of 9, the IZ width of 14 mm, and the tube diameter of 9 mm with the pressure uniformity of 0.529. The relative errors of the predicted pressure uniformity values by NN and MARS under the optimal design are 1.62% and 3.89%, respectively. This reveals that NN and MARS can accurately predict the pressure uniformity, and are promising tools for the design of PEMFCs. 相似文献
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Weakening the tight coupling between geometry and simulation in isogeometric analysis: From sub‐ and super‐geometric analysis to Geometry‐Independent Field approximaTion (GIFT) 下载免费PDF全文
Elena Atroshchenko Satyendra Tomar Gang Xu Stéphane P.A. Bordas 《International journal for numerical methods in engineering》2018,114(10):1131-1159
This paper presents an approach to generalize the concept of isogeometric analysis by allowing different spaces for the parameterization of the computational domain and for the approximation of the solution field. The method inherits the main advantage of isogeometric analysis, ie, preserves the original exact computer‐aided design geometry (for example, given by nonuniform rational B‐splines), but allows pairing it with an approximation space, which is more suitable/flexible for analysis, for example, T‐splines, LR‐splines, (truncated) hierarchical B‐splines, and PHT‐splines. This generalization offers the advantage of adaptive local refinement without the need to reparameterize the domain, and therefore without weakening the link with the computer‐aided design model. We demonstrate the use of the method with different choices of geometry and field spaces and show that, despite the failure of the standard patch test, the optimum convergence rate is achieved for nonnested spaces. 相似文献
48.
Qui X. Lieu Jaehong Lee 《International journal for numerical methods in engineering》2017,112(13):2025-2047
The paper introduces a novel multiresolution scheme to topology optimization in the framework of the isogeometric analysis. A new variable parameter space is added to implement multiresolution topology optimization based on the Solid Isotropic Material with Penalization approach. Design density variables defined in the variable space are used to approximate the element analysis density by the bivariate B‐spline basis functions, which are easily obtained using k‐refinement strategy in the isogeometric analysis. While the nonuniform rational B‐spline basis functions are used to exactly describe geometric domains and approximate unknown solutions in finite element analysis. By applying a refined sensitivity filter, optimized designs include highly discrete solutions in terms of solid and void materials without using any black and white projection filters. The Method of Moving Asymptotes is used to solve the optimization problem. Various benchmark test problems including plane stress, compliant mechanism inverter, and 2‐dimensional heat conduction are examined to demonstrate the effectiveness and robustness of the present method. 相似文献
49.
We investigate the use of smooth spline spaces over regular triangulations as a tool in (isogeometric) Galerkin methods. In particular, we focus on box splines over three-directional meshes. Box splines are multivariate generalizations of univariate cardinal B-splines sharing the same properties. Tensor-product B-splines with uniform knots are a special case of box splines. The use of box splines over three-directional meshes has several advantages compared with tensor-product B-splines, including enhanced flexibility in the treatment of the geometry and stiffness matrices with stronger sparsity. Boundary conditions are imposed in a weak form to avoid the construction of special boundary functions. We illustrate the effectiveness of the approach by means of a selection of numerical examples. 相似文献
50.
多元自适应样条回归是一种有效的针对高维数据回归建模方法,将该算法应用于入侵检测系统,根据入侵检测中存在的噪声数据和异常数据问题,提出了基于模糊算法的多元自适应样条回归方法。通过基于KDD1999数据集的训练和测试,与SVM在数据集上的测试结果进行对比,得出结论:该算法在入侵检测应用方面优于SVM算法。 相似文献