确定型模糊多重集有限自动机的极小化

主要研究确定型模糊多重集有限自动机的状态极小化问题。给出了模糊多重集有限自动机的同余和同态概念,并利用同余和同态关系研究了确定型模糊多重集有限自动机的极小化问题。进一步从确定型模糊多重集有限自动机自身出发,构造出极小模糊多重集有限自动机,并给出了极小化的算法。     

扰动模糊有限状态机的转移结构

利用代数方法和扰动模糊集的概念,引入了扰动模糊有限状态机概念。为研究扰动模糊有限状态机的转移结构,提出了扰动模糊有限状态机的扰动后继、扰动子系统、扰动子机、扰动生成元、扰动基等概念,并研究了其相关性质。     

基于正态分布对模糊概念自动计算的FPDA应用设计

计算机控制系统具有自动机的特征,可以用有限自动机理论来对其进行描述,有限自动机是计算机科学各个方面的重要基石。但除确定性的有限自动机理论外,还有许多模糊事件应该由模糊自动机的隶属函数来解决,文中将重点放在具有正态分布特征的事件上。提出了一种实现自动运算的模糊自动机模型,若要在正态分布中得到“可能发生”和“很可能发生”这类模糊型事件的概率,可以只用这种模型实现自动计算。     

BCI-代数的扰动模糊q-理想*

将扰动模糊集应用于BCI-代数中,引入了BCI-代数的扰动模糊q-理想的概念,研究了它相关性质,讨论了扰动模糊q-理想与扰动模糊理想、扰动模糊子代数之间的关系,给出了扰动模糊q-理想的几个等价刻画和扩展定理,指出了BCI-代数的扰动模糊q-理想的同态象与同态原象在一定条件下仍是扰动模糊q-理想。     

含不匹配扰动非严格反馈系统的输出反馈补偿控制

针对一类非严格反馈非线性系统,系统中包含不确定函数和未知外部扰动,提出一种带不匹配扰动补偿的输出反馈模糊控制器.采用模糊逻辑系统逼近未知的非线性函数,同时构造模糊状态观测器观测系统未知状态.考虑观测器和控制器会受到外部扰动和模糊逼近误差构成的不匹配总扰动信号影响,采用改进的扰动观测器对不匹配扰动进行估计和补偿,使扰动观测误差能够在有限时间内平缓地收敛到任意小的范围,消除不匹配扰动信号对模糊观测器设计的影响.同时在控制器设计中进行扰动的精确补偿,提高系统的抗扰动性.通过Lyapunov函数证明了闭环系统所有信号都是有界的.最后,通过数值仿真进一步验证了所提出方法的有效性.     

模糊有限自动机的最小化算法优化

现有的模糊自动机最小化算法没有涉及到对模糊自动机状态的隶属度迁移和变化的讨论,优化的模糊自动机最小化算法弥补了这类算法的不足之处。该算法将模糊有限自动机首先转化为单个初始状态的模糊自动机,然后再将转化后的模糊自动机化简为最小模糊自动机,算法在转化过程中单独讨论了模糊自动机状态隶属度的转化方式,使得算法更加严谨和简化。     

类严格反馈系统的模糊弱扰动解耦控制

大多数实际系统含有不确定项,且受到扰动的影响.采用模糊逻辑方法估计不确定项是降低不确定性影响的常见方法之一,而模糊近似扰动解耦是抑制扰动影响的主要手段.模糊近似扰动解耦对应的增益不等式包含无界项,所以无实际价值,为此提出模糊弱扰动解耦的控制方法.该方法采用模糊万能逼近定理估计不确定项,利用反步法设计控制器使得闭环系统具有弱扰动解耦性能,即闭环系统稳定且输出的范数不大于正常数加上扰动范数与正常数之积.仿真结果验证了模糊弱扰动解耦控制器能够保证闭环系统的弱扰动解耦性能.     

Lukasiewicz逻辑值上下文无关语言的代数刻画

提出了基于Lukasiewicz逻辑的下推自动机（l-VPDA）的概念,从代数角度研究了此类自动机的性质,同时建立此类自动机的代数刻画,即利用模糊状态构造,证明了任意以终状态方式接受模糊语言的l-VPDA与状态转移为经典函数且具有l值模糊终状态的l-VPDA间的相互等价性;并证明任意以空栈方式接受模糊语言的l-VPDA与状态转移除一步转移为模糊的以外,其余都是经典函数的l-VPDA是相互等价的;详细研究了l-值模糊上下文无关语言的代数和层次刻画,以及对于正则运算的封闭性。     

水利工程用液压清淤泵模糊自抗扰控制方法设计

水利工程用液压清淤泵受阶跃负载扰动的影响导致工作效率降低。为有效提升液压清淤泵工作效率、降低阶跃负载扰动带来的影响,提出一种针对水利工程用液压清淤泵的模糊自抗扰控制方法。首先,确定液压清淤泵自抗扰控制过程中相关影响因素;再基于影响因素分析结果确定液压清淤泵模糊自抗扰控制流程对影响因素进行控制;最后实现水利工程用液压清淤泵模糊自抗扰控制。实验证明:该方法得到的液压清淤泵负载扰动值与实际负载扰动值相接近,可以准确估计阶跃负载扰动;控制水利工程用液压清淤泵后,液压清淤泵响应速度较快,含淤值在0.030L/min左右,容积效率为98.73%,整体控制效果较好。     

一类严格反馈系统变比例增益精确微分补偿控制

针对包含不确定函数和未知外部扰动的一类严格反馈型非线性系统,提出基于精确扰动观测器的变比例增益自适应模糊控制器.系统中的未知不确定函数由模糊逻辑系统在线逼近,同时将模糊逻辑系统的逼近误差和未知外部扰动定义为总扰动,利用精确扰动观测器进行精确微分补偿控制. 将非线性函数应用于设计可调节的输出反馈增益,有效消除系统的稳态误差,使得系统跟踪误差可以控制在零的任意小邻域内.最后,通过Lyapunov定理证明闭环系统中所有信号均是有界的.数值仿真表明了所提出方案的有效性.     

The relationships among several types of fuzzy automata

We discuss the relationships among several types of fuzzy automata in which all fuzzy sets are defined by membership functions whose codomains are a lattice-ordered monoid L. These automata include nondeterministic L-valued finite automata with Λ-move, nondeterministic L-valued finite automata, deterministic L-valued finite automata, and L-valued finite-state automata. We consider all that come with fuzzy initial states and fuzzy final states or with crisp initial states or crisp final states. Some comparative results concerning the power of fuzzy automata used in the existing literature to recognize fuzzy languages are given systematically.     

Stochastic grammars and languages

This paper summarizes some recent results concerned with the extension of formal languages to their corresponding stochastic versions. Weighted grammars and languages are first defined, and stochastic grammars and languages are defined as a special case of weighted grammars and languages. Fuzzy grammars and languages, which have some properties similar to weighted grammars and languages, are also discussed. Stochastic automata are defined from the language recognition viewpoint. Languages accepted by stochastic finite-state and pushdown automata, with and without a cutpoint, are studied. Weighted and stochastic programmed and indexed grammars, and stochastic nested stack automata are defined. Finally, some decidability problems of stochastic (weighted, fuzzy) languages are discussed, and problems for further research are suggested.This work was supported by the National Science Foundation Grant GK-18225.     

Formal power series and regular operations on fuzzy languages

In this paper we study formal power series over a quantale with coefficients in the algebra of all languages over a given alphabet, and representation of fuzzy languages by these formal power series. This representation generalizes the well-known representation of fuzzy languages by their cut and kernel languages. We show that regular operations on fuzzy languages can be represented by regular operations on power series which are defined by means of operations on ordinary languages. We use power series in study of fuzzy languages which are recognized by fuzzy finite automata and deterministic finite automata, and we study closure properties of the set of polynomials and the set of polynomials with regular coefficients under regular operations on power series.     

Deciding co-observability is PSPACE-complete

In this note, we reduce the deterministic finite-state automata intersection problem to the problem of deciding co-observability for regular languages using a polynomial-time many-one mapping. This demonstrates that the problem of deciding co-observability for languages marked by deterministic finite-state automata is PSPACE-complete. We use a similar reduction to reduce the deterministic finite-state automata intersection problem to deciding other versions of co-observability introduced in a previous paper. These results imply that the co-observability of regular languages most likely cannot be decided in polynomial time unless we make further restrictions on the languages. These results also show that deciding decentralized supervisor existence is PSPACE-complete and therefore probably intractable.     

Regular grammars with truth values in lattice-ordered monoid and their languages

In this study, we introduce the concept of lattice-valued regular grammars. Such grammars have become a necessary tool for the analysis of fuzzy finite automata. The relationship between lattice-valued finite automata (LA) and lattice-valued regular grammars (LRG) are discussed and we get the following results, for a given LRG, there exists an LA such that they accept the same languages, and vice versa. We also show the equivalence between deterministic lattice-valued regular grammars and deterministic lattice-valued finite automata.     

Finite fuzzy automata, regular fuzzy languages, and pattern recognition

Fuzzy set theory is summarized, and finite fuzzy automata and languages are described. Some results in fuzzy languages based on the “max(min)” rule are discussed. An application of fuzzy languages in syntactic pattern analysis is described and is illustrated by a simple example.     

Sufficient conditions of deterministic implementation of finite-state automata with retention of the numbers of their states

The following three conditions for nondeterministic finite-state automata are defined: input embeddability, output embeddability, and input decomposability. Automata satisfying these conditions are called nondeterministic automata with embeddability. A method for deterministic implementation of such automata with retention of the numbers of their states is proposed. These automata correspond to block-procedural high-level programming languages. Translated from Kibernetika i Sistemnyi Analiz, No. 3, pp. 55–62, May–June, 2000.     

Intuitionistic fuzzy recognizers and intuitionistic fuzzy finite automata

Intuitionistic fuzzy recognizers and intuitionistic fuzzy finite automata are discussed. The notions of intuitionistic fuzzy recognizer, complete accessible intuitionistic fuzzy recognizer, intuitionistic fuzzy finite automata, deterministic intuitionistic fuzzy finite automata, and intuitionistic fuzzy language are introduced. It is shown that the languages recognized by intuitionistic fuzzy recognizer are regular, and the intuitionistic fuzzy languages recognized by the intuitionistic fuzzy finite automaton and the intuitionistic fuzzy languages recognized by deterministic intuitionistic fuzzy finite automaton are equivalent. This work is supported by National Science Foundation of China (Grant No.10571112), “TRAPOYT” of China and National 973 Foundation Research Program(Grant No.2002CB312200).     

Fuzzy multiset finite automata and their languages

Inspired by the generalizations from grammars and finite automata to fuzzy grammars and fuzzy finite automata, respectively, we introduce the concepts of fuzzy multiset grammars and fuzzy multiset finite automata (FMFAs), as the generalizations of multiset grammars and multiset finite automata, respectively. The relationship between fuzzy multiset regular grammars and FMFAs is discussed. Furthermore, we define some operations on fuzzy multiset languages, and prove that the family of FMFA languages is closed under the operations.