汉语三字词声调的模式分析

汉语三字词的声调模式是复杂的。本文对4 男4 女各192 个三字词的声调进行分析,选择各音节的头尾差和相对调位比为特征,在进行特征抽取、统计和分析的基础上,研究了三字调整声调的模式和变调规则。本文的结果对三字词和连续语音声调的识别具有重要价值。     

Bayesian Landmark Learning for Mobile Robot Localization

To operate successfully in indoor environments, mobile robots must be able to localize themselves. Most current localization algorithms lack flexibility, autonomy, and often optimality, since they rely on a human to determine what aspects of the sensor data to use in localization (e.g., what landmarks to use). This paper describes a learning algorithm, called BaLL, that enables mobile robots to learn what features/landmarks are best suited for localization, and also to train artificial neural networks for extracting them from the sensor data. A rigorous Bayesian analysis of probabilistic localization is presented, which produces a rational argument for evaluating features, for selecting them optimally, and for training the networks that approximate the optimal solution. In a systematic experimental study, BaLL outperforms two other recent approaches to mobile robot localization.     

一种融合PCA 和KFDA 的人脸识别方法

提出一种融合PCA和KFDA的人脸识别方法，即在进行非线性映射之前，首先利用经典的主分量分析(C—PCA)进行降维，然后执行KFDA．为进一步降低整个算法的计算时问，又提出一种I—PCA KFDA方法，它直接基于图像矩阵的主分量分析(I—PCA)．ORL标准人脸库的试验结果表明，与现有的核Fisher鉴别分析方法相比，两种方法可将特征抽取的速度分别提高3倍和7倍，其识别精度没有丝毫的降低．     

Boundary Layers in an Ocean Related System

In this article two regularizations of an hyperbolic model system derived from the primitive equations of the ocean (or the atmosphere) are presented. The two regularized systems converge to different limits as the regularization parameter converges to 0. Numerical approximations of these equations and numerical simulations are also presented     

会展建筑中的大空间排烟系统分析

通过对会展建筑中的大空间展厅的火灾情形、排烟量及排烟方式的分析,得出了一个适合此类建筑的排烟系统设计的经济合理的参考方案.     

蒸发器母液循环泵、过料泵泵壳泄漏分析及对策

介绍我公司氧化铝厂KESTNER蒸发器母液循环泵、过料泵泵壳的泄漏情况 ,分析泄漏原因 ,提出相应的改进措施     

关于剖面符号边界问题的研究

总结了剖面符号可能的四种边界类型,指出了常见的边界错误情况,论证了剖视图中剖面符号不能穿越粗实线。     

Thermal characterization of gallium arsenic nitride epilayer on gallium arsenide substrate using pulsed photothermal reflectance technique

Thermal conductivity of gallium arsenic nitride (GaAsN) epilayer on gallium arsenide (GaAs) substrate prepared by molecular beam epitaxy technique was measured using pulsed photothermal reflectance technique. Three-layer model incorporated thermal boundary resistance was applied to extract the thermal properties from the sample's photothermal response. Within the thickness ranging from 20 to 80 nm, no thickness dependent relationship with thermal conductivity of GaAsN epilayer was found, and the average thermal conductivity is approximately 27 W/mK at room temperature. The thermal boundary resistance at the Au/GaAsN interface is in the order of 10⁻⁸ m²K/W.     

Numerical Modeling of Grain Boundary Effects in the Diffusional Creep of Copper Interconnect Lines

We propose a numerical simulation technique to model the process of diffusional creep and stress relaxation that occurs in Cu-damascene interconnects of integrated circuit devices in processing stage. The mass flow problem is coupled to the stress analysis through vacancy flux and equilibrium vacancy concentration. The technique is implemented in a software package that seamlessly integrates the problem-oriented code with commercially available finite element program MSC.Marc. It is utilized to model the Coble creep phenomenon by introducing the nanoscale grain boundary region having the thickness on the order of several layers of atoms. As an illustration, the two-dimensional problem of stress relaxation in a single grain subjected to prescribed displacements and tractions is examined.     

Influence of grain boundaries on short crack growth behaviour of IGSCC

Understanding short crack behaviour is essential for predicting the lifetime of light water reactor components. However, crack growth rates of short cracks are unsteady due to microstructural obstacles such as grain boundaries. On the other hand, the statistical behaviour of short cracks can be deduced from crack size distributions. Some papers have pointed out that the crack size distributions obtained by stress corrosion cracking tests showed a kink in the distribution line. This kink suggests that the short crack growth rate is slow compared with that of long cracks. And it can be thought that the slow growth rate is caused by the microstructural obstacles. This study investigated the influence of grain boundaries on the short crack growth behaviour of intergranular stress corrosion cracking. A crack growth simulation model, which considered the mechanical effects of the crack kink and bifurcation by grain boundaries, was developed. The crack depth distribution obtained by the simulation also exhibited a kink in the distribution line as seen in the experimental results. This suggests that grain boundaries play an important role in short crack growth behaviour.