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1.
Universal learning network and its application to robust control   总被引:6,自引:0,他引:6  
Universal learning networks (ULNs) and robust control system design are discussed, ULNs provide a generalized framework to model and control complex systems. They consist of a number of interconnected nodes where the nodes may have any continuously differentiable nonlinear functions in them and each pair of nodes can be connected by multiple branches with arbitrary time delays. Therefore, physical systems which can be described by differential or difference equations and also their controllers can be modeled in a unified way. So, ULNs constitute a superset of neural networks or fuzzy neural networks. In order to optimize the systems, a generalized learning algorithm is derived for the ULNs, in which both the first order derivatives (gradients) and the higher order derivatives are incorporated. The derivatives are calculated by using forward or backward propagation schemes. These algorithms for calculating the derivatives are extended versions of back propagation through time (BPTT) and real time recurrent learning (RTRL) by Williams in the sense that generalized nonlinear functions and higher order derivatives are dealt with. As an application of ULNs, the higher order derivative, one of the distinguished features of ULNs, is applied to realizing a robust control system in this paper. In addition, it is shown that the higher order derivatives are effective tools to realize sophisticated control of nonlinear systems. Other features of ULNs such as multiple branches with arbitrary time delays and using a priori information will be discussed in other papers.  相似文献
2.
This paper discusses parallel wire mechanisms where an end-effector of the mechanism is suspended by multiple wires. The mechanisms enable not only three-dimensional (3-D) positioning but also 3-D orienting of the end-effector, unlike typical wire suspension-type mechanisms such as overhead crane. To discuss the parallel-wire-suspended mechanisms generally, two forms of basic dynamic equations are presented. Then the parallel wire mechanisms are classified into two types based on the basic equations. Dynamical properties of the two types of wire-suspended positioning mechanism are discussed. In this paper, one of the wire-suspended mechanism, incompletely restrained-type parallel wire mechanism, is mainly discussed on its inverse dynamics problem and its trajectory control problem. The inverse dynamics problem for the incompletely restrained-type mechanism plays an important role on its control problem, because the mechanism has low stiffness based on incomplete constraints on the suspended object which is governed by its dynamics. The paper proposes an antisway control method for the suspended object. In the method, the inverse dynamics calculation is used for nonlinear dynamics compensation to control the suspended object of the incompletely restrained parallel wire mechanism.  相似文献
3.
Acquiring 3-D models from sequences of contours   总被引:5,自引:0,他引:5  
This paper explores shape from contour for acquiring 3-D graphics models. In this method, a continuous sequence of images is taken as an object rotates. A smooth convex shape can be estimated instantaneously from its contour and by the first derivative of contour movement (trace of contour, or contour distribution with time). We also analyze shapes that do not satisfy the conditions of smoothness and visibility, which are indispensable for modeling an object. A region that does not expose as contour yields a nonsmoothness in the tracked contour movement. We can thus detect such a region by contour distribution filtering and extract its accurate location by computing the left and right derivatives of the distribution. This has not been studied previously. These unknown regions are obtained for further investigation using other visual cues. A general approach for building a geometrical object model using contours is then described. The entire process from silhouettes to a 3-D model is based local computation; this is promising for producing shapes in real time. Our direct goal is to establish 3-D graphics models of human faces for the growing needs of visual communications. We have obtained some good results  相似文献
4.
K-winners-take-all circuit with O(N) complexity   总被引:4,自引:0,他引:4  
Presents a k-winners-take-all circuit that is an extension of the winner-take-all circuit by Lazzaro et al. (1989). The problem of selecting the largest k numbers is formulated as a mathematical programming problem whose solution scheme, based on the Lagrange multiplier method, is directly implemented on an analog circuit. The wire length in this circuit grows only linearly with the number of elements, and the circuit is more suitable for real-time processing than the Hopfield networks because the present circuit produces the solution almost instantaneously-in contrast to the Hopfield network, which requires transient convergence to the solution from a precise initial state. The selection resolution in the present circuit is, however, only finite in contrast to the almost infinite resolution in the Hopfield networks.  相似文献
5.
研究了一种新的带有开关机制的ULN建模方法, 不仅对其中的参数而且对时间延迟都进行了调整以适应非线性系统的建模要求. 对非线性系统识别问题的仿真结果表明, 所提方法具有比仅使用参数优化的传统方法更好的性能. 还用带有开关机制的ULN对网络规模是如何影响动态系统泛化能力的问题进行了研究.  相似文献
6.
Learning Petri network and its application to nonlinear systemcontrol   总被引:3,自引:0,他引:3  
According to recent knowledge of brain science it is suggested that there exists functions distribution, which means that specific parts exist in the brain for realizing specific functions. This paper introduces a new brain-like model called Learning Petri Network (LPN) that has the capability of functions distribution and learning. The idea is to use Petri net to realize the functions distribution and to incorporate the learning and representing ability of neural network into the Petri net. The obtained LPN can be used in the same way as a neural network to model and control dynamic systems, while it is distinctive to a neural network in that it has the capability of functions distribution. An application of the LPN to nonlinear crane control systems is discussed. It is shown via numerical simulations that the proposed LPN controller has superior performance to the commonly-used neural network one.  相似文献
7.
Environmental gas sensing   总被引:3,自引:0,他引:3  
Solid-electrolyte sensors for detecting air pollutants are urgently needed for the sake of environmental protection. Rapid progress is being marked in the development of sensors for CO2, NO2, NO, SO2, ozone and fluorocarbons. Some of them, such as the CO2 sensor, have almost reached a stage of practical application, while others are very promising. Most of these sensors have been fabricated with ceramic materials that are solid electrolytes and oxide semiconductors. The current status of research and development for air-pollutant sensing is described briefly.  相似文献
8.
Division-based analysis of symmetry and its application   总被引:2,自引:0,他引:2  
A computational method, DAS, is proposed for symmetry analysis of a planar figure closed by a simply connected curve. DAS determines both the symmetric axis and the symmetric point pairs on the curve, consistently, based on the duality of two geometric plane divisions, the Delaunay triangulation and the Voronoi diagram  相似文献
9.
10.
A Model for Slicing JAVA Programs Hierarchically   总被引:2,自引:0,他引:2       下载免费PDF全文
Program slicing can be effectively used to debug, test, analyze, understand and maintain objectoriented software. In this paper, a new slicing model is proposed to slice Java programs based on their inherent hierarchical feature. The main idea of hierarchical slicing is to slice programs in a stepwise way, from package level, to class level, method level, and finally up to statement level. The stepwise slicing algorithm and the related graph reachability algorithms are presented, the architecture of the Java program Analyzing TOol (JATO) based on hierarchical slicing model is provided, the applications and a small case study are also discussed.  相似文献
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