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111.
112.
具有多值约束的线性递归查询的有效计算 总被引:1,自引:0,他引:1
本文给出三个算法,分别用于把给定的右线性、左线性或左-右线性递归程序改写为一组更有效的规则.与Ullman等人的变换算法不同,本文的算法允许查询的初始约束可以是含任意多个约束元组的集合,而不必是单值的;这样,本文的算法不仅可以用于查询的求值,而且也可以用于子目标的处理.变换算法的正确性和变换后规则的有效性也在本文简略讨论. 相似文献
113.
A new curvature technique calculation for surface tension contribution in PLIC-VOF method 总被引:1,自引:0,他引:1
The volume of fluid (VOF) methods have been used for numerous numerical simulations. Among these techniques used to define
the moving interface, the piecewise linear interface reconstruction (PLIC-VOF) is one of the most accurate. A study of the
superficial tension impact on two-phase flow with free surface is presented. A new method based on direct staggered grid is
developped to include surface tension in PLIC-VOF. The new numerical curvature calculation method doesn't need smoothed colour
function and leads to less “spurious current”. This technique is applied to the calculus of surface tension force in the case
of the rise of air bubble in viscous liquid and the fall of liquid drop in the same liquid on free surface. Droplets, thin
layer and capillarity waves are observed after the free surface rupture for different Bond number. The influence of surface
tension calculus is then obvioused and when the drop hit the free surface, wavelets propagate toward the virtual boundaries
imposed. 相似文献
114.
William E Acree Jr Michael H Abraham 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2006,81(8):1441-1446
The contentions made in an earlier paper [J Chem Technol Biotechnol 80 : 133–137 (2005)] that the coefficients of the Abraham solvation equation do not provide meaningful information on the molecular properties of ionic liquid solvents is refuted. The objections noted in the earlier paper disappear when the solvation equation model is correctly applied to the experimental data. It is further shown that the coefficients of the Abraham solvation equations can be used to characterize ionic liquids and can be used to select solvents for the solubility of gaseous solutes. Copyright © 2006 Society of Chemical Industry 相似文献
115.
High accuracy path tracking for vehicles in presence of sliding: Application to farm vehicle automatic guidance for agricultural tasks 总被引:1,自引:0,他引:1
Roland Lenain Benoit Thuilot Christophe Cariou Philippe Martinet 《Autonomous Robots》2006,21(1):79-97
When designing an accurate automated guidance system for vehicles, a major problem is sliding and pseudo-sliding effects. This is especially the case in agricultural applications, where five-centimetre accuracy with respect to the desired trajectory is required, although the vehicles are moving on slippery ground. It has been established that RTK GPS was a very suitable sensor to achieve automated guidance with such high precision: several control laws have been designed for vehicles equipped with this sensor, and provide the expected guidance accuracy as long as the vehicles do not slide. In previous work, further control developments have been proposed to take sliding into account: guidance accuracy in slippery environments has been shown to be preserved, except transiently at the beginning/end of curves. In this paper, the design of this control law is first recalled and discussed. A Model Predictive Control method is then applied in order to preserve accuracy of guidance even during these curvature transitions. Finally, the overall control scheme is implemented, and improvements with respect to previous guidance laws are demonstrated through full-scale experiments. 相似文献
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This paper derives the admissible decompositions for a time series dynamic linear model, assuming only that the model is observable. The decompositions depend on factorizations of the characteristic polynomial of the state evolution matrix G into relatively prime factors. This generalizes the method of West (1997 ) which considers one decomposition in the particular case where G is diagonalizable. Conditions are derived for a decomposition to be independent. These results show that no autoregressive process of order d has an independent decomposition for any integer d . Two illustrations of this procedure are discussed in detail. 相似文献
119.
T. Bag 《Information Sciences》2006,176(19):2910-2931
In this paper, definitions of strongly fuzzy convergent sequence, l-fuzzy weakly convergent sequence and l-fuzzy weakly compact set are given in a fuzzy normed linear space. The concepts of fuzzy normal structure, fuzzy non-expansive mapping, uniformly convex fuzzy normed linear space are introduced and fixed point theorems for fuzzy non-expansive mappings are proved. 相似文献
120.
自适应相干噪声衰减技术 总被引:6,自引:0,他引:6
去除噪声是必需的地震数据处理过程。由于地表条件和地震波激发、传播以及接收条件等诸多方面的原因,时常引起地震记录上出现各种相干干扰波。本文主要针对地震数据处理中地震剖面上存在的各种相干噪声,提出了时问一空间域自适应相干噪声衰减技术,以进行信噪分离。这种方法把噪声在整个处理平面上的视速度近似看作常量(正值或负值),可以有效地消除地震剖面上的线性噪声、面波以及多次波等,并且对信号的保真度高。本文方法是复杂地区低信噪比地震数据处理的一种理想的噪声去除方法,具有运算速度快、压制噪声效果好等优点。 相似文献