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1.
Geodesic Active Contours   总被引:17,自引:17,他引:167  
A novel scheme for the detection of object boundaries is presented. The technique is based on active contours evolving in time according to intrinsic geometric measures of the image. The evolving contours naturally split and merge, allowing the simultaneous detection of several objects and both interior and exterior boundaries. The proposed approach is based on the relation between active contours and the computation of geodesics or minimal distance curves. The minimal distance curve lays in a Riemannian space whose metric is defined by the image content. This geodesic approach for object segmentation allows to connect classical snakes based on energy minimization and geometric active contours based on the theory of curve evolution. Previous models of geometric active contours are improved, allowing stable boundary detection when their gradients suffer from large variations, including gaps. Formal results concerning existence, uniqueness, stability, and correctness of the evolution are presented as well. The scheme was implemented using an efficient algorithm for curve evolution. Experimental results of applying the scheme to real images including objects with holes and medical data imagery demonstrate its power. The results may be extended to 3D object segmentation as well.  相似文献
2.
熵在随机系统故障诊断和容错控制中的应用   总被引:14,自引:14,他引:0  
长期以来,关于随机动态系统的故障诊断和容错控制的研究一直是控制理论和应用的重要领域之一。随机控制系统故障诊断的目标是建立有效的故障估计算法以使残差信号方差最小。这种方法仅适用于高斯型残差或者具有对称分布的概率密度函数的残差。然而,对非高斯残差而言,仅使用残差信号的方差不能够全面表示残差的不确定性。针对非高斯随机动态控制系统提出了新的故障诊断和容错控制算法,以使故障诊断中残差信号的熵极小化,同时极小化故障状态下闭环控制系统跟踪误差的熵。  相似文献
3.
一种LabWindows/CVI与MATLAB混合编程的实现方法   总被引:14,自引:14,他引:7  
Labwindows/CVI是一套面向测控领域的优秀软件开发平台;MATLAB具有强大的数据处理函数库和多样且简易的绘图方法。本文提出的修改LabWindows/CVI和MATLAB的ActiveX服务函数,并进行封装、建立动态连接库的方法.为用户实现Labwindows/CVI共享MATLAB的软件工具包.拓宽LabWindows/CVI在测控领域的应用.提高编程效率提供了有益的帮助。文末给出了LabWindows/CVI和MATLAB混合编程的实例。  相似文献
4.
Boolean Feature Discovery in Empirical Learning   总被引:7,自引:7,他引:12  
5.
Exploring dynamic self-adaptive populations in differential evolution   总被引:7,自引:7,他引:1  
Although the Differential Evolution (DE) algorithm has been shown to be a simple yet powerful evolutionary algorithm for optimizing continuous functions, users are still faced with the problem of preliminary testing and hand-tuning of the evolutionary parameters prior to commencing the actual optimization process. As a solution, self-adaptation has been found to be highly beneficial in automatically and dynamically adjusting evolutionary parameters such as crossover rates and mutation rates. In this paper, we present a first attempt at self-adapting the population size parameter in addition to self-adapting crossover and mutation rates. Firstly, our main objective is to demonstrate the feasibility of self-adapting the population size parameter in DE. Using De Jong's F1–F5 benchmark test problems, we showed that DE with self-adaptive populations produced highly competitive results compared to a conventional DE algorithm with static populations. In addition to reducing the number of parameters used in DE, the proposed algorithm actually outperformed the conventional DE algorithm for one of the test problems. It was also found that that an absolute encoding methodology for self-adapting population size in DE produced results with greater optimization reliability compared to a relative encoding methodology.  相似文献
6.
系统鲁棒性的若干问题——背景、现状与挑战*   总被引:6,自引:6,他引:23  
本文进行系统鲁棒性分析的综述,全文分四节,第1节是引言,给出了问题的缘由、现代鲁棒分析的提法与一些基本概念,第2节介绍并评论了多项式代数方法的一些突破性进展,如Kharitonov定理、棱边定理与其它一些结果,在第3节中,对稳定矩阵的摄动界分析和基于状态空间描述与李亚普诺夫方法的鲁棒性的讨论作了介绍,最后在第4节中论述了基于输入输出描述的方法和H~∞方法。  相似文献
7.
Asynchronous Stochastic Approximation and Q-Learning   总被引:6,自引:6,他引:15  
We provide some general results on the convergence of a class of stochastic approximation algorithms and their parallel and asynchronous variants. We then use these results to study the Q-learning algorithm, a reinforcement learning method for solving Markov decision problems, and establish its convergence under conditions more general than previously available.  相似文献
8.
基于分解与动态规划策略的汉语未登录词识别   总被引:6,自引:6,他引:25  
未登录词的识别是汉语自动分词中的主要问题,本文以对中国人名,中国地名和外国译名进行整体识别为目标,采用分解处理策略降低了整体处理难度,并使用动态规划方法实现了最佳路径的搜索,较好地解决了未登录词之间的冲突问题,通过对真实语料识别的测试,证明该方法可以提高未登录词识别的正确率和召回率。  相似文献
9.
动态流程模拟及其在精馏塔的操作分析中的应用   总被引:6,自引:6,他引:6  
采用HYSYS流程模拟软件,对丙烯丙烷精馏塔进行动态流程模拟,分析了丙烯丙烷精馏塔在操作条件变化和进料流量及进料成分干扰变化时,整个塔的动态响应变化过程,研究了常规PID控制方案以及通常的先进控制方案所存在的问题,为改进的集实时优化与先进控制于一体的控制方案设计提供了依据。  相似文献
10.
Discovering correlated spatio-temporal changes in evolving graphs   总被引:6,自引:6,他引:0  
Graphs provide powerful abstractions of relational data, and are widely used in fields such as network management, web page analysis and sociology. While many graph representations of data describe dynamic and time evolving relationships, most graph mining work treats graphs as static entities. Our focus in this paper is to discover regions of a graph that are evolving in a similar manner. To discover regions of correlated spatio-temporal change in graphs, we propose an algorithm called cSTAG. Whereas most clustering techniques are designed to find clusters that optimise a single distance measure, cSTAG addresses the problem of finding clusters that optimise both temporal and spatial distance measures simultaneously. We show the effectiveness of cSTAG using a quantitative analysis of accuracy on synthetic data sets, as well as demonstrating its utility on two large, real-life data sets, where one is the routing topology of the Internet, and the other is the dynamic graph of files accessed together on the 1998 World Cup official website.
Jeffrey ChanEmail:
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