共查询到19条相似文献，搜索用时 203 毫秒
1.
A fast integration method for translating-pulsating source Green’s function in Bessho form简 总被引：1，自引：0，他引：1
The singularities and oscillatory performance of translating-pulsating source Green＇s function in Bessho form were analyzed. Relative numerical integration methods such as Gaussian quadrature rule, variable substitution method （VSM）, and steepest descent integration method （SDIM） were used to evaluate this type of Green＇s function. For SDIM, the complex domain was restricted only on the 0-plane. Meanwhile, the integral along the real axis was computed by use of the VSM to avoid the complication of a numerical search of the steepest descent line. Furthermore, the steepest descent line was represented by the B-spline function. Based on this representation, a new self-compatible integration method corresponding to parametric t was established. The numerical method was validated through comparison with other existing results, and was shown to be efficient and reliable in the calculation of the velocity potentials for the 3D seakeeping and hydrodynamic performance of floating struc- tures moving in waves. 相似文献
2.
In this paper, a new method named as the gradually descent method was proposed to solve the discrete global optimization problem. With the aid of an auxiliary function, this method enables to convert the problem of finding one discrete minimizer of the objective function f to that of finding another at each cycle. The auxiliary function can ensure that a point, except a prescribed point, is not its integer stationary point if the value of objective function at the point is greater than the scalar which is chosen properly. This property leads to a better minimizer of f found more easily by some classical local search methods. The computational results show that this algorithm is quite efficient and reliable for solving nonlinear integer programming problems. 相似文献
3.
Accuracy and fastness of iris localization are very important in automatic iris recognition. A new fast iris localization algorithm based on improved generalized symmetry transform (GST) was proposed by utilizing iris symmetry. GST was improved in three aspects: 1 ) A new distance weight function is defined. The new weight function, which is effective in iris localization, utilized the characteristic of irises that the iris is a circular object and it has one inner boundary and one outer boundary. 2) Each calculation of the symmetry measurement of a pair of symmetry points was performed by taking one point of a pair as the starting point of the transformation. This is the most important reason for fast iris localization, due to which, repetitious computation was largely excluded. 3) A new phase weight function was proposed to adjust GST to locate circle target much better because the inner part of iris is darker than the outer part. The edge map of iris image was acquired and GST was only implemented on the edge point, which decreased computation without loss of accuracy. The modification of distance weight function and phase weight function leads to the accuracy of localization, and other ideass peed up the localization. Experiments show that the average speed of new algorithm is about 7.0-8.5 times as high as traditional ones including integro-differential operator and Hough transform method. 相似文献
4.
In this paper, the LCVM mixing rule is extended to the multi-parameter equations of state by combining infinite-pressure and zero-pressure mixing rule models. The new LCVM-type mixing rule, coupled with Patel-Teja equation of state （EOS） is applied for vapor-liquid equilibria of different polar and non-polar systems in which the NRTL activity coefficient model is used to calculate the excess Gibbs free energy. The tested results agree well with existing experimental data within a wide range of temperatures and pressures. In comparison with the Van der Waals mixing rule, the new mixing rule gives much better correlations for the vapor-liquid equilibria of non-polar and polar systems. 相似文献
5.
Interior-point methods （IPMs） for linear optimization （LO） and semidefinite optimization （SDO） have become a hot area in mathematical programming in the last decades. In this paper, a new kernel function with simple algebraic expression is proposed. Based on this kernel function, a primal-dual interior-point methods （IPMs） for semidefinite optimization （SDO） is designed. And the iteration complexity of the algorithm as O（n^3/4 log n/ε） with large-updates is established. The resulting bound is better than the classical kernel function, with its iteration complexity O（n log n/ε） in large-updates case. 相似文献
6.
Rule Generation Based on Dominance Matrices and Functions 总被引：2，自引：0，他引：2
Rough set theory has proved to be a useful tool for rule induction. But, the theory based on indiscemibility relation or similarity relation cannot induce rules from decision tables with criteria. Greco et al have proposed a new rough set approach based on dominance relation to handle the problems. In this paper, the concept of dominance matrix is put forward and the dominance function is constructed to compute the minimal decision rules that are more general and applicable than the ones induced by the classical rough set theory. In addition,the methodology of simplification is presented to eliminate the redundancy in the rule set. 相似文献
7.
Mesoscopic characteristics of a clayey soil specimen subjected to macroscopic loading are examined using a medical-use computerized tomography （CT） instrument. Disturbed state concept （DSC） theory is based on the utilization of the hardening model. DSC indirectly describes material behavior by claiming that the actual response of the material is expressed in terms of the relative intact （RI） response and the fully adjusted （FA） response. The occurrence of mesoscopic structural changes of material has similarities with the occurrence of a macroscopic response of the material under loadings. In general, the relative changing value of a softening material is three to five times more than that of a hardening material. Whether special zones exist or not in a specimen cross section does not affect the following conclusion： hardening material and softening material show mechanical differences with CT statistical indices values prominently changing, and the change is related to the superposing of a disturbance factor. A new disturbance factor evolution function is proposed. Thus, mesoscopic statistical indices are introduced to describe macroscopic behavior through the new evolution function. An application of the new evolution function proves the effectiveness of the amalgamation of a macroscopic and a mesoscopic experimental phenomenon measurement methods. 相似文献
8.
For an arbitrary subset P of the reals, a function f ： V →P is defined to be a P-dominating function of a graph G = （V, E） if the sum of its function values over any closed neighbourhood is at least 1. That is, for every v ∈ V, f（N[v]） ≥ 1. The definition of total P-dominating function is obtained by simply changing ‘closed＇ neighborhood N[v] in the definition of P-dominating function to ‘open＇ neighborhood N（v）. The （total） P-domination number of a graph G is defined to be the infimum of weight w（f） = ∑v ∈ V f（v） taken over all （total） P-dominating function f. Similarly, the P-edge and P-star dominating functions can be defined. In this paper we survey some recent progress on the topic of dominating functions in graph theory. Especially, we are interested in P-, P-edge and P-star dominating functions of graphs with integer values. 相似文献
9.
Mean decision power （MDP） is an important criterion of a new reduction model, and relative decision power （RDP） and amount of rules （AR） are key parameters of MDP. This paper presents two important properties： relationship between RDP and AR, and relationship between MDP rule set of parent decision table and MDP rule set of child decision table. These properties can help better understanding of the new reduction model and are useful tools by which one can rapidly derive an MDP rule set. 相似文献
10.
V. B. Saputra S. K. Ong A. Y. C. Nee 《上海大学学报(英文版)》2014,(3):222-230
This paper presents a calibration method for parallel manipulators using a measurement system specially installed on an external fixed frame. The external fixed frame is important as an error reference for calibration in certain operations, such as in the configuration of a parallel manip- ulator functioning as a machine tool where the workpiece is fixed to a worktable. The pose of the end-effector is mea- sured using three digital indicators installed on the external fixed frame. To enable measurement, the end-effector is assumed to be a plane large enough that all digital indicators could touch. The error is defined as the difference between the theoretical and actual readings of the digital indicators. The geometric parameters of the parallel manipulator are optimized to minimize this error. This calibration method is low cost and feasible for compensating geometric parameter errors for a parallel manipulator. Optimal pose selection for the calibration is achieved using a swarm intelligence search algorithm. The method is implemented on a prototype of a six degrees-of-freedom （DOFs） Gough-Stewart platform constructed to function as a machine tool. 相似文献
11.
提出一个新的修正Hestenes-Stiefel(HS)非线性共轭梯度法(MHSCG算法).在精确线搜索下MH-SCG算法化归为标准的HS共轭梯度算法.该算法产生的搜索方向不依赖于线搜索准则而具有充分下降性.新方法在一个修正Armijo型线搜索下具有全局收敛性.数值试验表明,对于多数算例新算法比PRP、HS、LS算法具有更好的计算结果. 相似文献
12.
An efficient method for tracing planar implicit curves 总被引：1，自引：0，他引：1
YU Zheng-sheng CAI Yao-zhi OH Min-jae KIM Tae-wan PENG Qun-sheng 《浙江大学学报(A卷英文版)》2006,7(7):1115-1123
INTRODUCTION Tracing a planar implicit curve f(x, y)=0 on a rectangular region [xl, xr]×[yb, yt] is of great interest in Computer-Aided Design and Computer Graphics. While parametric curves are easy to plot, plotting implicit curves is a challenging problem. Planar im- plicit curve plotting method can be classified into two categories (Shou et al., 2005; Martin et al., 2002; Lopes et al., 2002). In the first category are subdivi- sion methods (Shou et al., 2005; Martin et al., 2002) … 相似文献
13.
本文采用集中性和多样性策略对禁忌搜索进行改进,提出了一种基于模糊神经网络的混合禁忌搜索优化算法(FNN-based Hybrid Tabu Search Algorithm,FNN-HTS),用于同时优化模糊神经网络的结构和参数以提取出一组尽量精练的模糊规则。在FNN-HTS中,禁忌搜索用于同时优化网络结构和隶属函数参数,结合最小二乘法快速求解规则后件的线性参数。非线性函数逼近的实验结果表明所提出的方法能获得一组更精练的规则和更小的误差。 相似文献
14.
How do young children most readily learn new concepts and rules? The authors contribute a new study to the literature on this important subject. They tested two design strategies on 69 elementary school children to investigate (a) the effect of using three types of pictorial supports to focus student attention on the important features of a concept or rule as described in accompanying written material and (b) the importance of specific pretraining instruction on how to use the pictorial to notice and label relevant rules and concepts. Posttests showed it works better to supply pictures than to have students draw their own, and both these methods work better than having students form mental images of the material studied. All three types of pictorials required about the same student time-on-task. The authors also found that specific pretraining instruction in how to use the pictorials is very important. The learning task involved two arithmetical rules—intersection and empty set. 相似文献
15.
提出了一种改进的LS共轭梯度法,该方法具有不依赖于所采用的线搜索方法的充分下降性.并证明了该方法在Armijo型搜索下求解非凸问题的全局收敛性,相关的数值实验结果检验了算法的有效性. 相似文献
16.
田婧 《湖南第一师范学报》2009,9(2):130-132
目的论包含目的法则、连贯法则和忠实法则。通过分析可以发现,王佐良的英译本《雷雨》符合目的论的三个法则．实现了他的预期目的。译本把握了原作的创作精神,再现了戏剧人物形象——谈吐恰如其人,语气切合其境,句式流畅明快。 相似文献
17.
Kikumi K. Tatsuoka Menucha Birenbaum Jerry Arnold 《Journal of Educational Measurement》1989,26(4):351-361
The purpose o f this study was to examine the consistency with which students applied procedural rules for solving signed-number operations across identical items presented in different orders. A test with 64 open-ended items was administered to 161 eighth graders. The test consisted o f two 32-item subtests containing identical items. The items in each subtest were in random order. Students'responses to each subtest were compared with respect to the identified underlying rules o f operation used to solve each problem set. The results indicated that inconsistent rule application was common among students who had not mastered signed-number arithmetic operations. In contrast, mastery level students, those who use the right rules, show a stable pattern o f rule application in signed-number arithmetic. These results are discussed in light of the hypothesis testing approach to the learning process. 相似文献
18.
把综合测评规则界定为学校与学院指导下的研究生自治规则,既可以体现对研究生主体地位的尊重，又能为学校与学院的指导、监督提供依据。综合测评规则是测评周期内评价研究生客观表现的依据，承载着引导、认知、衡量三个基础功能。研究生综合测评的主要问题包括规则缺位引发的矛盾、规则不明引起的冲突、解决方式导致的纷争。解决问题的总体思路是确立综合测评规则的权威，通过正当程序优化规则的修订和运行机制，探索外在权威转化为规则权威的方法，畅通诉求表达渠道。基于实践的探索和研究，为研究生综合素质评价体系的科学化、规范化构建贡献了个案智慧。 相似文献