首页 | 官方网站   微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 437 毫秒
1.
提出了一种基于茶学词典和统计算法相结合的茶学知识概念抽取方法。该方法以茶学词典为基础,首先对非结构化数据源进行中文分词处理,然后采用两种统计算法对分词结果进行概念抽取。通过使用丰富的茶学词典来降低统计算法时间复杂度,提高了中文分词和概念抽取的精度和效率。实验结果表明,词库的丰富程度决定了概念抽取的效果,可以通过不断丰富词库,进一步提高概念抽取精度。  相似文献   

2.
提出了一种基于茶学词典和统计算法相结合的荼学知识概念抽取方法。该方法以茶学词典为基础,首先对非结构化数据源进行中文分词处理,然后采用两种统计算法对分词结果进行概念抽取。通过使用丰富的荼学词典来降低统计算法时间复杂度,提高了中文分词和概念抽取的精度和效率。实验结果表明,词库的丰富程度决定了概念抽取的效果,可以通过不断丰富词库,进一步提高概念抽取精度。  相似文献   

3.
One approach to data analysis in recognition problems on precedents is investigated. The search task for logical regularities of the classes is considered. The concept of elementary predicate is introduced. This predicate determines the belonging of the object to any half-space in the space of features. The logical regularities, which are the disjunctive forms from elementary predicates, are examined. The search methods for these logical regularities are proposed. These methods are based on the constructing convex hulls of subsets of the training sample.  相似文献   

4.
The fuzzy weighted average (FWA), which is a function of fuzzy numbers and is useful as an aggregation method in engineering or management science based on fuzzy sets theory. It provides a discrete approximate solution by α-cuts level representation of fuzzy sets and interval analysis. Since the FWA method has an exponential complexity, thus several researches have focused on reducing this complexity. This paper also presents an enhanced fuzzy weighted average approach to achieve the objective of reducing the complexity. This proposed approach is through an improved initial solution for original FWA algorithm, and a two-phase concept by extending and applying both the algorithms of Chang et al. [4] and Guu [14]. Although the complexity of the proposed FWA algorithm is O(n) the same as Guu [14] which is the best level achieved to date. But from the experimental results appear that the proposed algorithm is more efficient, which only needs a few evaluated numbers and spend much less overall CPU time than Guu [14] and other FWA algorithms. In order to demonstrate the usefulness of this study, a practical example for unmanned aerial vehicle (UAV) selecting under military requirement has illustrated. Additionally, a computer-based interface, which helps the decision maker make decisions more efficiently, has been developed.  相似文献   

5.
一种基于决策矩阵的属性约简及规则提取算法   总被引:17,自引:1,他引:16  
研究了Rough集理论中属性约简和值约简问题,扩展了决策矩阵的定义,提出了一种基于决策矩阵的完备属性约简算法,该算法利用决策属性把论域划分成多个等价类,然后利用每个等价类对应的决策矩阵计算属性约简。与区分矩阵相比,采用决策矩阵可以有效地减少存储空间,提高约简算法效率。同时,借助决策矩阵进行值约简,提出了一种新的规则提取算法,使最终得到的决策规则更加简洁。实验结果表明,本文提出的属性约简和值约简算法是正确、有效、可行的。  相似文献   

6.
In this paper, we propose new adaptive algorithms for the extraction and tracking of the least (minor) or eventually, principal eigenvectors of a positive Hermitian covariance matrix. The main advantage of our proposed algorithms is their low computational complexity and numerical stability even in the minor component analysis case. The proposed algorithms are considered fast in the sense that their computational cost is O(np) flops per iteration where n is the size of the observation vector and p<n is the number of eigenvectors to estimate.We consider OJA-type minor component algorithms based on the constraint and non-constraint stochastic gradient technique. Using appropriate fast orthogonalization procedures, we introduce new fast algorithms that extract the minor (or principal) eigenvectors and guarantee good numerical stability as well as the orthogonality of their weight matrix at each iteration. In order to have a faster convergence rate, we propose a normalized version of these algorithms by seeking the optimal step-size. Our algorithms behave similarly or even better than other existing algorithms of higher complexity as illustrated by our simulation results.  相似文献   

7.
为了减少时钟偏差规划所需的时间,提出一种准线性时间复杂度的时钟偏差规划方法.该方法以整数来描述延迟大小的时钟偏差规划算法,限制每次对时钟延迟调整的步进至少为1,降低了算法的时间复杂度;改变了传统的预先生成完整的时序图作为算法输入的流程,采用一种新的增量式延迟提取策略为时钟偏差规划算法提取关键边的权重,减少了生成时序图所需要的时间.实验结果表明,采用文中方法进行时钟偏差规划的效率很高,对包含数千触发器的基准测试电路,其运行时间仅为数十秒.  相似文献   

8.
Two novel algorithms for the fast computation of the Zernike and Pseudo-Zernike moments are presented in this paper. The proposed algorithms are very useful, particularly in the case of using the computed moments, as discriminative features in pattern classification applications, where the computation of single moments of several orders is required. The derivation of the algorithms is based on the elimination of the factorial computations, by computing recursively the fractional terms of the orthogonal polynomials being used. The newly introduced algorithms are compared to the direct methods, which are the only methods that permit the computation of single moments of any order. The computational complexity of the proposed method is O(p 2) in multiplications, with p being the moment order, while the corresponding complexity of the direct method is O(p 3). Appropriate experiments justify the superiority of the proposed recursive algorithms over the direct ones, establishing them as alternative to the original algorithms, for the fast computation of the Zernike and Pseudo-Zernike moments.  相似文献   

9.
Object contours contain important visual information which can be applied to numerous vision tasks. As recent algorithms focus on the accuracy of contour detection, the entailed time complexity is significantly high. In this paper, we propose an efficient and effective contour extraction method based on both local cues from pixels and global cues from saliency. Experimental results demonstrate that a good trade-off between accuracy and speed can be achieved by the proposed approach for contour detection.  相似文献   

10.
Traditional Support Vector Machine (SVM) solution suffers from O(n 2) time complexity, which makes it impractical to very large datasets. To reduce its high computational complexity, several data reduction methods are proposed in previous studies. However, such methods are not effective to extract informative patterns. In this paper, a two-stage informative pattern extraction approach is proposed. The first stage of our approach is data cleaning based on bootstrap sampling. A bundle of weak SVM classifiers are constructed on the sampled datasets. Training data correctly classified by all the weak classifiers are cleaned due to lacking useful information for training. To further extract more informative training data, two informative pattern extraction algorithms are proposed in the second stage. As most training data are eliminated and only the more informative samples remain, the final SVM training time is reduced significantly. Contributions of this paper are three-fold. (1) First, a parallelized bootstrap sampling based method is proposed to clean the initial training data. By doing that, a large number of training data with little information are eliminated. (2) Then, we present two algorithms to effectively extract more informative training data. Both algorithms are based on maximum information entropy according to the empirical misclassification probability of each sample estimated in the first stage. Therefore, training time can be further reduced for training data further reduction. (3) Finally, empirical studies on four large datasets show the effectiveness of our approach in reducing the training data size and the computational cost, compared with the state-of-the-art algorithms, including PEGASOS, LIBLINEAR SVM and RSVM. Meanwhile, the generalization performance of our approach is comparable with baseline methods.  相似文献   

11.
An approach to the construction of algorithms that are efficient for complexity and that calculate -solutions to computation and applied mathematics problems is described in the first part of the present paper. This approach is applied for creation of T-efficient algorithms used to solve some classes of nonlinear integral equations, ordinary differential equations, and global optimization.  相似文献   

12.
Abstract: Feature extraction helps to maximize the useful information within a feature vector, by reducing the dimensionality and making the classification effective and simple. In this paper, a novel feature extraction method is proposed: genetic programming (GP) is used to discover features, while the Fisher criterion is employed to assign fitness values. This produces non‐linear features for both two‐class and multiclass recognition, reflecting the discriminating information between classes. Compared with other GP‐based methods which need to generate c discriminant functions for solving c‐class (c>2) pattern recognition problems, only one single feature, obtained by a single GP run, appears to be highly satisfactory in this approach. The proposed method is experimentally compared with some non‐linear feature extraction methods, such as kernel generalized discriminant analysis and kernel principal component analysis. Results demonstrate the capability of the proposed approach to transform information from the high‐dimensional feature space into a single‐dimensional space by automatically discovering the relationships between data, producing improved performance.  相似文献   

13.
针对线性的互信息特征提取方法,通过研究互信息梯度在核空间中的线性不变性,提出一种快速、高效的非线性特征提取方法。该方法采用互信息二次熵快速算法及梯度上升的寻优策略,提取有判别能力的非线性高阶统计量;在计算时避免传统非线性特征提取中的特征值分解运算,有效降低计算量。通过UCT数据的投影和分类实验表明,该方法无论在投影空间的可分性上,还是在算法时间复杂度上,都明显优于传统算法。  相似文献   

14.
Zhao  Guodong  Wu  Yan 《Neural Processing Letters》2019,50(2):1257-1279

As known, the supervised feature extraction aims to search a discriminative low dimensional space where the new samples in the sample class cluster tightly and the samples in the different classes keep away from each other. For most of algorithms, how to push these samples located in class margin or in other class (called hard samples in this paper) towards the class is difficult during the transformation. Frequently, these hard samples affect the performance of most of methods. Therefore, for an efficient method, to deal with these hard samples is very important. However, fewer methods in the past few years have been specially proposed to solve the problem of hard samples. In this study, the large margin nearest neighbor (LMNN) and weighted local modularity (WLM) in complex network are introduced respectively to deal with these hard samples in order to push them towards the class quickly and the samples with the same labels as a whole shrink into the class, which both result in small within-class distance and large margin between classes. Combined WLM with LMNN, a novel feature extraction method named WLMLMNN is proposed, which takes into account both the global and local consistencies of input data in the projected space. Comparative experiments with other popular methods on various real-world data sets demonstrate the effectiveness of the proposed method.

  相似文献   

15.
The aim of this paper is to use formal power series techniques to study the structure of small arithmetic complexity classes such as GapNC 1 and GapL. More precisely, we apply the formal power series operations of inversion and root extraction to these complexity classes. We define a counting version of Kleene closure and show that it is intimately related to inversion and root extraction within GapNC 1 and GapL. We prove that Kleene closure, inversion, and root extraction are all hard operations in the following sense: there is a language in AC 0 for which inversion and root extraction are GapL-complete and Kleene closure is NLOG-complete, and there is a finite set for which inversion and root extraction are GapNC 1 -complete and Kleene closure is NC 1 -complete, with respect to appropriate reducibilities. The latter result raises the question of classifying finite languages so that their inverses fall within interesting subclasses of GapNC 1 , such as GapAC 0 . We initiate work in this direction by classifying the complexity of the Kleene closure of finite languages. We formulate the problem in terms of finite monoids and relate its complexity to the internal structure of the monoid. Some results in this paper show properties of complexity classes that are interesting independent of formal power series considerations, including some useful closure properties and complete problems for GapL.  相似文献   

16.
针对传统克隆选择算法的不足,提出了一个基于球面杂交的新型克隆选择算法。在该算法的每次迭代过程中,动态地计算出每个抗体的变异概率,根据抗体的亲和度将抗体种群动态分为记忆单元和一般抗体单元,并以球面杂交方式对种群进行调整,从而加快了算法的全局搜索速度。实例验证了所提算法的有效性、可行性。  相似文献   

17.
基于内容的图像检索(Content-based Image Retrieval,CBIR)以其极高的理论与应用价值成为了图像处理领域的研究热点。提取和匹配图像特征是CBIR的主要手段。然而提取图像的有效特征是极其困难的。利用HSV颜色空间特性以及人类对颜色的感知规律,提出一种颜色识别方法。应用此方法对图像的像素进行一种保持结构的分类,并在类内提取结构特征。图像的特征匹配将在同类像素集合间进行,降低了图像特征提取与匹配的复杂性。实验表明,提出的图像检索方法有良好的效果。  相似文献   

18.
Proposes a theoretical model for analysis of classification methods, in which the teacher knows the classification algorithm and chooses examples in the best way possible. The authors apply this model using the nearest-neighbor learning algorithm, and develop upper and lower bounds on sample complexity for several different concept classes. For some concept classes, the sample complexity turns out to be exponential even using this best-case model, which implies that the concept class is inherently difficult for the NN algorithm. The authors identify several geometric properties that make learning certain concepts relatively easy. Finally the authors discuss the relation of their work to helpful teacher models, its application to decision tree learning algorithms, and some of its implications for experimental work  相似文献   

19.
Several classes of sequential algorithms to approximate themaximum acyclic subgraph problem are examined. The equivalentfeedback arc set problem isNP-complete and there are only a few classes of graphs for which it is known to be inP. Thus, approximation algorithms are very important for this problem. Our goal is to determine how effectively the various sequential algorithms parallelize. Of the sequential algorithms we study, natural decision problems based on several of them are provedP-complete. Parallel implementations usingO(log ¦V¦) time and ¦E¦ processors on an EREW PRAM exist for the other algorithms. Interestingly, the parallelizable algorithms appear very similar to some of theinherently sequential algorithms. Thus, for approximating the maximum acyclic subgraph problem small algorithmic changes drastically alter parallel complexity, unlessNC equalsP.  相似文献   

20.
This paper proposes a cost-effective and edge-directed image super-resolution scheme. Image super-resolution (image magnification) is an enthusiastic research area and is desired in a variety of applications. The basic idea of the proposed scheme is based on the concept of multi-kernel approach. Various stencils have been defined on the basis of geometrical regularities. This set of stencils is associated with the set of kernels. The value of a re-sampling pixel is obtained by calculating the weighted average of the pixels in the selected kernel. The time complexity of the proposed scheme is as low as that of classical linear interpolation techniques, but the visual quality is more appealing because of the edge-orientation property. The experimental results and analysis show that proposed scheme provides a good combination of visual quality and time complexity.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号