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91.
Toshihiko Hoshide Junpei Fujita 《Journal of Materials Engineering and Performance》2008,17(5):627-632
Strength of ground ceramics may be affected by residual stress as well as surface flaws induced by grinding. Strength prediction
for ground ceramics is convenient for mechanical design of ceramic components. In this article, a numerical procedure based
on fracture mechanics was proposed to estimate strength distribution of ground ceramics by considering grinding-induced residual
stress. Bending strength and residual stress of ground ceramics were measured for three grinding-conditions. By comparison
of simulated results with experimental ones, it was revealed that strength characteristics in experiments were well simulated
by using the proposed procedure. 相似文献
92.
Morten
rregaard Nielsen 《时间序列分析杂志》2005,26(2):279-304
Abstract. We consider semiparametric estimation in time‐series regression in the presence of long‐range dependence in both the errors and the stochastic regressors. A central limit theorem is established for a class of semiparametric frequency domain‐weighted least squares estimates, which includes both narrow‐band ordinary least squares and narrow‐band generalized least squares as special cases. The estimates are semiparametric in the sense that focus is on the neighbourhood of the origin, and only periodogram ordinates in a degenerating band around the origin are used. This setting differs from earlier studies on time‐series regression with long‐range dependence, where a fully parametric approach has been employed. The generalized least squares estimate is infeasible when the degree of long‐range dependence is unknown and must be estimated in an initial step. In that case, we show that a feasible estimate which has the same asymptotic properties as the infeasible estimate, exists. By Monte Carlo simulation, we evaluate the finite‐sample performance of the generalized least squares estimate and the feasible estimate. 相似文献
93.
H. Luo 《Microsystem Technologies》2006,12(4):324-329
This paper focuses on tracking, reconstruction and motion estimation of a well-defined MEMS optical switch from a microscopic
view. For out-of-view reconstruction, a homography capable of transforming feature points and feature lines between a microscopic
image and a CAD model of the switch is implemented. The homography between two sequential microscopic images is decomposed
and factorized for motion estimation. Optical flow has also been explored to provide rough estimations of rotation centre
and angle. The paper also illustrates motion parameter optimization principles to deal with uncertainty inherent in micro
world. After non-linear optimization, estimation accuracy for rotation angle and rotation centre can reach 0.06° and pixel
level, respectively. 相似文献
94.
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97.
The discrimination problem for two normal populations with the same covariance matrix when additional information on the population is available is considered. A study of the robustness properties against training sample contamination of classification rules that incorporate this additional information is performed. These rules have received recently attention where their total misclassification probability (TMP) is proved to be lower than Fisher's linear discriminant rule. The results of a simulation study on the TMP which compares the behaviour of the new rules against Fisher's rule and some of its robustified versions under different types of contamination are presented. These results show that the rules that incorporate the additional information not only have lower TMP, but they also prevent against some types of contamination. In order to achieve prevention from all types of contamination a robustifed version of these rules is recommended. 相似文献
98.
A. K. Srivastava Ram M. Shrestha S. C. Srivastava Rabin Shrestha Dharam Paul 《国际能源研究杂志》2003,27(7):671-685
The power sector in India at present comprises of five separate regional electricity grids having practically no integrated operation in between them. This study analyses the utility planning, environmental and economical effects of integrated power sector development at the national level in which the regional electric grids are developed and operated as one integrated system. It also examines the effects of selected CO2 emission reduction targets in the power sector and the role of renewable power generation technologies in India. The study shows that the integrated development and operation of the power system at the national level would reduce the total cost including fuel cost by 4912 million $, total capacity addition by 2784 MW, while the emission of CO2, SO2 and NOx would be reduced by 231.6 (1.9%), 0.8 (0.9%), 0.4 (1.2%) million tons, respectively, during the planning horizon. Furthermore, the study shows that the expected unserved energy, one of the indices of generation system reliability, would decrease to 26 GWh under integrated national power system from 5158 GWh. As different levels of CO2 emission reduction targets were imposed, there is a switching of generation from conventional coal plants to gas fired plants, clean coal technologies and nuclear based plants. As a result the capacity expansion cost has increased. It was found that wind power plant is most attractive and economical in the Indian perspective among the renewable options considered (Solar, wind and biomass). Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
99.
浅谈建筑企业施工项目部的成本控制 总被引:1,自引:0,他引:1
指出控制工程项目的直接费用要从“四算对比”入手,介绍了施工项目的成本分析方法,阐述了施工项目内部控制的主要措施,以确保施工成本控制在计划成本范围内。 相似文献
100.
GPS RTK(Real Time Kinematic)技术的快速定位功能为其应用创造了良好的条件,但其定位精度验后估计的欠缺又使其应用受到一定的限制。本文针对此问题进行了研究,给出了GPS RTK测量成果的精度估计方法,并对GPS RTK测量技术用于控制测量的可行性进行了探讨,导出了相应的测量限差,为CPS RTK测量技术用于控制测量提供了理论依据和技术规定。 相似文献