共查询到20条相似文献，搜索用时 316 毫秒
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基于Wu-Ritt特征集方法和V.Gerdt的对合除法, 我们定义了非线性偏微分方程组的关于一般延拓方向的对合特征集 (ICS). 影响ICS方法的两个主要因素为: 延拓方向和变量的序. 本文中, 应用ICS方法处理在计算偏微分方程组的对称群过程中产生的大型偏微分方程组. 在实验的基础上, 总结了对于ICS方法较好的延拓方向和变量的序. 相似文献
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Xiao-feng Song Wei-min Chen Yi-Ping Phoebe Chen Bin Jiang 《Information processing & management》2009,45(5):584-592
Sequential minimal optimization (SMO) is quite an efficient algorithm for training the support vector machine. The most important step of this algorithm is the selection of the working set, which greatly affects the training speed. The feasible direction strategy for the working set selection can decrease the objective function, however, may augment to the total calculation for selecting the working set in each of the iteration. In this paper, a new candidate working set (CWS) Strategy is presented considering the cost on the working set selection and cache performance. This new strategy can select several greatest violating samples from Cache as the iterative working sets for the next several optimizing steps, which can improve the efficiency of the kernel cache usage and reduce the computational cost related to the working set selection. The results of the theory analysis and experiments demonstrate that the proposed method can reduce the training time, especially on the large-scale datasets. 相似文献
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Automatic text classification is the problem of automatically assigning predefined categories to free text documents, thus allowing for less manual labors required by traditional classification methods. When we apply binary classification to multi-class classification for text classification, we usually use the one-against-the-rest method. In this method, if a document belongs to a particular category, the document is regarded as a positive example of that category; otherwise, the document is regarded as a negative example. Finally, each category has a positive data set and a negative data set. But, this one-against-the-rest method has a problem. That is, the documents of a negative data set are not labeled manually, while those of a positive set are labeled by human. Therefore, the negative data set probably includes a lot of noisy data. In this paper, we propose that the sliding window technique and the revised EM (Expectation Maximization) algorithm are applied to binary text classification for solving this problem. As a result, we can improve binary text classification through extracting potentially noisy documents from the negative data set using the sliding window technique and removing actually noisy documents using the revised EM algorithm. The results of our experiments showed that our method achieved better performance than the original one-against-the-rest method in all the data sets and all the classifiers used in the experiments. 相似文献
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Ibrahim Develi 《Journal of The Franklin Institute》2005,342(1):69-84
This paper considers the problem of detecting the optimal spreading codes (OSC) in a given code set for a direct sequence-code division multiple access system that employs despreading sequences weighted by adjustable chip waveforms. Due to computational complexity required to detect the OSC in a code set, a simple and efficient strategy is introduced. Analysis and numerical results show that the proposed strategy can successfully distinguish the spreading codes being most suitable references for a given code set in which the candidate spreading codes have equal crosscorrelation properties. 相似文献
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租糙集理论作为一种处理不完备信息的有利工具,巳广泛应用于人工智能的许多领域,特别是数据挖掘和知识发现领域.文章将基于粗糙集理论的数据挖掘技术应用于钢结构缺陷模式识别的知识发现,在智能诊断的知识自动获取方面取得了较好的效果. 相似文献
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James A. Dyer 《Journal of The Franklin Institute》1975,299(1):9-31
This paper is a study of models of spaces of duration-limited signals considered as set functions. Models for the space of bounded signals, signals of bounded area and signals of finite energy are considered. It is shown that by using set function models and a Stieltjes integral for set functions one can derive integral representations for all bounded linear operators on each of these spaces. It is also shown that impulse functions can be treated rigorously as signals of bounded area in these models without introducing singularities, or requiring impulses to be considered as functionals on a signal space rather than as signals. Finally, analogues to differentiation and indefinite integration are introduced. The applications of these models to physical problems are illustrated by reformulating lumped parameter electrical network theory in a set function formalism, and approximate solutions to the resulting equations are shown. 相似文献
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In this paper we consider the problem of permuting a large sparse n×n matrix into an optimum bordered triangular form using nonsymmetric permutations. By making use of the degree switching operations in the digraph of the matrix and minimum essential set of the digraph we present a formal solution to the problem. Next we present an algorithm for finding a minimal essential set for a strongly connected digraph using the structural properties of the digraph. We also present an algorithm for permuting a n×n matrix into a near optimum bordered triangular form by making use of output set assignment concepts. Examples are given to illustrate our algorithms. 相似文献
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一种基于k最近邻的快速文本分类方法 总被引：5，自引：0，他引：5
k最近邻方法是一种简单而有效的文本分类方法,但是传统的k最近邻分类方法在搜索k个最近邻时需要高强度的相似性计算,尤其是在训练集数据量很大情况下,全局的最优搜索几乎是不可能的.因此,加速k个最近邻的搜索是k最近邻方法实用的关键.本文提出了一种基于k最近邻的快速文本分类方法,它能够保证在海量数据集中进行快速有效的分类.实验结果表明这一方法较传统方法性能有显著提升. 相似文献
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提出的方法能灵活地进行数据库SQL查询,它可以干扰一系列的约束条件,并且这种方法能够允许用户假定一组约束和查询一起。系统重写这个查询去查找相应的与约束一致的数据。这个重写是SQL,以便能被商业数据库系统有效地优化和执行。使用TPC-H基准的数据和查询比较脏数据多粒度的执行性能,实验显示该方法是可行的。 相似文献
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Shuang Shi Xin Lu Yujunrong Ma Shunqing Ren 《Journal of The Franklin Institute》2019,356(6):3644-3660
This paper is concerned with the output reachable set estimation for discrete-time switched systems. The switching signal is considered as persistent dwell-time (PDT), which is more general and flexible compared with the common dwell-time and average dwell-time switching. The estimation of output reachable set is determined by a collection of bounding ellipsoids based on a family of quasi-time-dependent (QTD) Lyapunov functions. Furthermore, a set of non-fragile QTD controllers is designed. Finally, two examples are employed to illustrate the potentials of proposed methods. 相似文献
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《专利审查指南》第一部分第三章第9．2．4规定,“成套产品外观设计专利申请中不应包含某一件或者几件产品的相似外观设计。”由于成套产品外观设计和相似外观设计两者存在范围上的重合,成套产品外观设计专利申诘中包含相似外观设计的情况仍时有出现。为此,本文从理论分析出发,对相关案例进行类型分析,力图为审查员和中请人给出实践中可操作的针对性建议。 相似文献
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[目的/意义]预警是情报分析工作的核心与难点。有效识别征候是成功预警的前提,一组有效的指标集合又是征候识别的基本依据,征候识别的精准度、对征候价值判断的准确性均需以精确的指标为参照。所以,探究预警监控指标集的构建方法是进行正确预警的基础性工作。[方法/过程]在前人理论研究的基础上,通过综合归纳与案例演绎的方法,在明确了"指标""征候"等预警基本概念及指标来源的基础上,设计提出了指标集的构建流程,明确了指标集的构建原则。[结果/结论]通过从巴基斯坦为防御国的视角出发,以印巴冲突为例,探究预警指标集的构建路径,基本确认了预警指标集"确定指标来源、提取指标、指标效度验证"的构建流程,明确了各流程的操作方法并探讨了该构建流程的普适性作用,为预警指标集构建路径在其他预测性领域的运用、预警指标体系与智能技术的结合提供了参考和依据。 相似文献
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作业是教师检测学生对所学知识的掌握情况和对教学方式进行查漏补缺的一种有效方式,有效提高中职英语作业的有效性和针对性成为英语教师的教学重点,本文从针对性、趣味性、综合性、板块式和归纳性等方面谈巧妙布置中职英语作业的策略。 相似文献
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分析了线性选择方法的两个缺陷,提出了一种基于聚集密度的非线性自适应选择方法。算法基本思想是：首先将每代种群划分成Pareto劣解集和Pareto非劣解集,然后依照个体的聚集密度分别在劣解集和非劣解集中构造一种偏序集,分别按照不同的等概率在这两个偏序集中选择个体,其中劣解偏序集的个体选择概率远小于非劣解偏序集的个体选择概率,根据两个偏序集中的容量自动计算出两个选择概率。这种非线性选择方法既体现了劣解集和非劣解集中个体的绝对平等性及非劣解集对劣解集的相对优先选择权,又充分考虑到了Pareto最优解的分布性。理论分析和数值计算表明,这种新的选择机制不仅能改善排序选择法的收敛性,而且能得到分布性良好的Pareto最优解。 相似文献
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《Information processing & management》2016,52(6):1074-1085
Literature shows interdisciplinary research as an essential driver for innovation. Ideas that are used as a starting point for this research are of an interdisciplinary nature because they combine aspects from different disciplines. The identification of interdisciplinary ideas at an early stage enables the start of interdisciplinary research and thus, it enables advances to be made in the innovation process. We propose a new methodology that combines semantic clustering and classification to estimate the interdisciplinary nature of ideas from a set of given ideas. The set is created automatically by use of an existing idea mining approach. Ideas from this set are semantically clustered to obtain concepts that are latent in the data. The relationship between each concept and each discipline pair from a set of given disciplines is calculated. Based on the degree of relationship, concepts are used to represent the interdisciplinary field spanned by the two disciplines. The ideas standing behind these concepts are identified as interdisciplinary ideas. As a result, the proposed methodology enables an estimation of the interdisciplinary nature of given ideas. The results might be helpful for researchers as well as for decision makers in the field of innovation management. 相似文献
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In this paper, we develop a matrix-based methodology to investigate the problems of stability and stabilizability for a deterministic finite automaton (DFA) in the framework of the semi-tensor product (STP) of matrices. First, we discuss the equilibrium point stability (resp., set stability) of a DFA, i.e., verifying whether or not all state trajectories starting from a subset of states converge to a specified equilibrium point (resp., subset of states). The necessary and sufficient conditions for verifying both stabilities are given, respectively. Second, equilibrium point stabilizability (resp., set stabilizability) of a DFA is investigated as verifying the issue of whether or not a DFA can be globally or locally stabilized to a specified equilibrium point (resp., subset of states) by a permissible state-feedback controller. Based on the pre-reachability set and invariant-subset defined in this paper, the matrix-based criteria for verifying equilibrium point stabilizability and set stabilizability are derived, respectively. Furthermore, for each type of stabilizability, all permissible state-feedback controllers for the case of minimal length state trajectories, called optimal state-feedback controllers, are characterized by using the proposed polynomial algorithms. Finally, two examples are presented to illustrate the effectiveness of the theoretical results. 相似文献