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1.
基于量子逻辑的自动机和文法理论   总被引:10,自引:1,他引:9       下载免费PDF全文
邱道文 《软件学报》2003,14(1):23-27
初步建立了基于量子逻辑的自动机和文法理论的基本框架.引入了量子文法(称为l值文法),特别是证明了任意l值正规文法生成的语言(称为量子语言)等价于某种基于量子逻辑且含动作(的自动机(称为l值自动机)识别的语言,反之,任意l值自动机识别的语言等价于某l值正规文法生成的语言.建立了l值泵引理,并得到量子语言的判定性刻画.最后简要讨论了正规文法与量子文法(即l值正规文法)的关系.因此,为进一步研究更复杂的量子自动机(如量子下推自动机和Turing机)和量子文法(如量子上下文无关文法和上下文有关文法)奠定了基础.  相似文献
2.
Petri网语言的Pumping引理   总被引:9,自引:0,他引:9  
Petri网语言是Petri网理论的重要组成部分,也是系统行为分析的一种重耍的工具.Petri网语言的Pumping引理反映了Petri网语言的共性,可用来证明某些语言不是Petri网语言,已经证明,当一个Petri网语言可被某个有界Petri网产生时,此语言是正规语言,因此,正规语言的Pumping引理对此语言是有效的,但正规语言的Pumping引理并小适用于所有的Petrl网语言.文中给出了一种Petri网语言的Pumping引理,证明其对任意无空标注的Petri网语言都有效,并且+正规语言的Pumping引理是此引理的一种特殊形式.利用此Pumping引理可以证明某些语言是不能由Petri网产生的。  相似文献
3.
正则语言的特征性质   总被引:3,自引:0,他引:3       下载免费PDF全文
叶瑞芬  沈百英 《软件学报》1995,6(7):416-419
通常的关于正则语言的泵引理实际上是刻划了某语言为正则语言的一个必要条件.本文通过修改这个必要条件,得到了关于正则语言的充分必要条件,又泵引理或广义泵引理所叙述的结果作为推论而得到.另外,我们叙述了几个强弱不同的充要条件,以便供不同的使用(作为必要条件来使用,应该是越强越好,但作为充分条件来使用,又应该是越弱越好).  相似文献
4.
量子自动机的刻画   总被引:2,自引:0,他引:2       下载免费PDF全文
邱道文 《软件学报》2003,14(1):9-15
澄清了各类量子自动机之间的相互关系,并给出了量子自动机的各种等价刻画定理.引入G-量子自动机、g-量子自动机、(广义)量子自动机及G-量子文法和g-量子文法,并阐明了它们与其他量子自动机之间的等价关系.在一定条件下讨论了G(g)-量子自动机与G(g)-量子文法的等价性,从而解决了关于量子文法产生量子正规语言的问题.讨论了量子语言与正规语言的关系,特别是回答了Gudder提出的两个公开问题.最后,给出了一种减少状态空间维数的方法.  相似文献
5.
Obtaining shorter regular expressions from finite-state automata   总被引:1,自引:0,他引:1  
We consider the use of state elimination to construct shorter regular expressions from finite-state automata (FAs). Although state elimination is an intuitive method for computing regular expressions from FAs, the resulting regular expressions are often very long and complicated. We examine the minimization of FAs to obtain shorter expressions first. Then, we introduce vertical chopping based on bridge states and horizontal chopping based on the structural properties of given FAs. We prove that we should not eliminate bridge states until we eliminate all non-bridge states to obtain shorter regular expressions. In addition, we suggest heuristics for state elimination that leads to shorter regular expressions based on vertical chopping and horizontal chopping.  相似文献
6.
上下文无关Petri网语言的Pumping引理   总被引:1,自引:0,他引:1  
Petri网语言可分为正规Petri网语言、上下文无关Petri网语言和Petri网语言三类,Pumping引理反映了一类语言的共性.对于正规Petri网语言类和Petri网语言类都已给出了其相应的Pumping引理,而对于上下文无关Petri网语言类的Pumping引理却一直未给出.本文通过分析上下文无关Petri网语言的结构性质,给出了上下文无关Petri网语言的Pumping引理,并且正规Petri网语言的Pumping引理是上下文无关Petri网语言的Pumping引理的一种特殊形式,而上下文无关Petri网语言的Pumping引理又是Petri网语言Pumping引理的一种特殊形式,从而完整地解决了三类Petri网语言Pumping引理以及它们之间的关系.  相似文献
7.
Various characterizations of codes are given with a finite synchronization delay. Decidability and bounds on the delay are established in particular cases.Work done at Summer Research Institute of the Canadian Mathematical Congress, supported by the National Research Council of Canada.  相似文献
8.
Regular model checking is a method for verifying infinite-state systems based on coding their configurations as words over a finite alphabet, sets of configurations as finite automata, and transitions as finite transducers. We introduce a new general approach to regular model checking based on inference of regular languages. The method builds upon the observation that for infinite-state systems whose behaviour can be modelled using length-preserving transducers, there is a finite computation for obtaining all reachable configurations up to a certain length n. These configurations are a (positive) sample of the reachable configurations of the given system, whereas all other words up to length n are a negative sample. Then, methods of inference of regular languages can be used to generalize the sample to the full reachability set (or an overapproximation of it). We have implemented our method in a prototype tool which shows that our approach is competitive on a number of concrete examples. Furthermore, in contrast to all other existing regular model checking methods, termination is guaranteed in general for all systems with regular sets of reachable configurations. The method can be applied in a similar way to dealing with reachability relations instead of reachability sets too.  相似文献
9.
We describe a new way to model deletion operations on formal languages, called deletion along trajectories. We examine its closure properties, which differ from those of shuffle on trajectories, previously introduced by Mateescu et al. In particular, we define classes of non-regular sets of trajectories such that the associated deletion operation preserves regularity. Our results give uniform proofs of closure properties of the regular languages for several deletion operations.

We also show that deletion along trajectories serves as an inverse to shuffle on trajectories. This leads to results on the decidability of certain language equations, including those of the form LTX=R, where L,R are regular languages and X is unknown.  相似文献

10.
We consider probabilistic automata on a general state space and study their computational power. The model is based on the concept of language recognition by probabilistic automata due to Rabin (Inform. Control 3 (1963) 230) and models of analog computation in a noisy environment suggested by Maass and Orponen (Neural Comput. 10 (1998) 1071), and Maass and Sontag (Neural Comput. 11 (1999) 771). Our main result is a generalization of Rabin's reduction theorem that implies that under very mild conditions, the computational power of such automata is limited to regular languages.  相似文献
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