项重写系统的并行实现方案

项重写系统的并行归约可以提高归约的效率，在无共享内存的Ｔｒａｎｓｐｕｔｅｒ网络上实现时要考虑任务的分配，项的拼装，归约任务的控制等问题，其中怎么样减少机间的机内进程的通信慢提高系统效果的关键。本文从控制方式角度讨论在不同拓扑结构的Ｔｒａｎｓｐｕｔｅｒ网络上实现项重写系统的方案，重点介绍基于树形结构下的控制方法，进程安排和通讯形式。     

项重写的图实现

图重写能够有效地实现项重写。文章从项重写的图实现的角度出发，研究了图重写模拟项重写的正确性和完备性：在无环出现的情况下，图重写对一切项重写下正确；在无环出现的条件下，图重写对左线性合流的项重写是完备的。     

依赖项重写系统及其在程序设计语言中的应用

面重写系统是一种简洁通用的计算模型,在许多领域中有着重要的应用。     

项重写系统等价性的归纳证明

尽管学者们在计算机软件理论及相关数学理论方面做出了不懈的努力,但伴随着计算机硬件的高速发展而来的软件危机却日益严峻,其原因复杂多样。其中,主要原因之一是缺乏程序验证的方法和工具。程序设计的主要步骤有:描述问题、设计程序、实现程序及测试程序。需要注意的是,这里是测试程序的正确性而非证明程序的正确性,这样程序的正确性就不能从根     

重写系统的模块分解

Ｍｉｄｄｅｌｄｏｒｐ和Ｔｏｙａｍａ证明，强加构造原则到项重写系统可获得完备概念的模块性，并且系统分解成的各部分间可共亨函数符号和重量写规则。本文推广他们的结论，当构造性的项重写系统引用定义在其它系统中的函数符号时，完备概念的模块性仍保持。该结论对代数规范和基于项重写的编程语言等方面是很有意义的。     

项重写系统弱基终止性的归纳证明

1.引言项重写系统是一种受到广泛研究和应用的形式计算模型。一个项重写系统由一组称为重写规则的定向等式组成。例如,下面的R是一个由五个重写规则组成的、定义用({0,s})表示的自然数集N上的两倍函数d(x)=2×n:N→N的项重写系统:     

基于项重写的动态可重构系统建模与仿真框架

可重构系统建模与仿真是一项复杂的任务.本文从可重构计算模式的基本特征出发,建立计算与通讯并重的生产者-消费者系统架构,并提取其数据、计算、通讯基本元素,解决运行时的调度和加载问题,形成基于项重写理论的动态可重构计算系统建模框架.最后指出基于本框架进行系统规范描述、系统设计和仿真验证的方法与步骤.并以实例说明了不同的调度策略产生满足不同规范的应用系统,显示了本框架的通用性.     

基于梯形逻辑的联锁系统形式化验证方法

铁路联锁系统设计通常采用梯形逻辑进行建模。为了实现对铁路联锁系统进行形式化验证的目的,根据梯形逻辑的状态变迁语义,将梯形逻辑表示的联锁系统模型转换成模型检测工具NuSMV的语言,并将铁路联锁系统的安全需求表示为计算树逻辑(CTL),最后实现基于NuSMV的铁路联锁系统设计模型的形式化验证。     

高效率重写型程序的设计

本文考虑如何设计高效率(即重写步数较少的)重写型程序。文中以计算Fibonacci数列的程序为例．比较具有相同功能的重写型程序,展示编写高效率重写型程序的可能性。介绍利用动态项重写计算编写高效率重写型程序的直观、简洁的方法。其中．动态项重写计算是项重写系统的元计算模型,其计算同样基于项重写。     

基于重写逻辑的UML模型一致性检查方法

在模型驱动开发的场景下,保证UML模型的一致性具有重要意义,但目前大多数UML／MDA工具仪提供了有限支持。该文提出了一种基于代数重写逻辑的UML模型一致性检查的方法。首先定义了基于两级代数规范的实施构架以分别检查UML模型的没讣时和运行时语义一致性,其次定义了检查包括类图、状态机图和顺序图在内的多图一致性的重写规则。该方法为保持面向可执行的UML模型的一致性提供了有效支持。     

Formal Semantics and Analysis of Component Connectors in Reo

We present an operational semantics for a component composition language called Reo. Reo connectors exogenously compose and coordinate the interactions among individual components that comprise a complex system, into a coherent collaboration. The formal semantics we present here paves the way for a rigorous study of the behavior of component composition mechanisms. To demonstrate the feasibility of such a rigorous approach, we give a faithful translation of Reo semantics into the Maude term rewriting language. This translation allows us to exploit the rewriting engine and the model-checking module in the Maude tool-set to symbolically run and model-check the behavior of Reo connectors.     

Prototyping SOS Meta-theory in Maude

We present a prototype implementation of SOS meta-theory in the Maude term rewriting language. The prototype defines the basic concepts of SOS meta-theory (e.g., transition formulae, deduction rules and transition system specifications) in Maude. Besides the basic definitions, we implement methods for checking the premises of some SOS meta-theorems (e.g., GSOS congruence meta-theorem) in this framework. Furthermore, we define a generic strategy for animating programs and models for semantic specifications in our meta-language. The general goal of this line of research is to develop a general-purpose tool that assists language designers by checking useful properties about the language under definition and by providing a rapid prototyping environment for scrutinizing the actual behavior of programs according to the defined semantics.     

Addressed Term Rewriting Systems: Syntax, Semantics, and Pragmatics: Extended Abstract

We present a formalism called Addressed Term Rewriting Systems, which can be used to define the operational semantics of programming languages, especially those involving sharing, recursive computations and cyclic data structures. Addressed Term Rewriting Systems are therefore well suited for describing object-based languages, as for instance the family of languages called , involving both functional and object-based features.     

TA4SP的认证性扩展

认证性是安全协议检测的重要特性之一,但TA4SP自动协议证明器无法对安全协议的认证性进行检测。针对该问题,提出一种TA4SP的认证性检测方法。该方法基于对TA4SP设计原理的分析,采用分层认证思想,实现对其认证性的理论扩展,其结构清晰、易于形式化。实例表明,通过该方法改进后的TA4SP能有效检测安全协议的认证性。     

A rewriting logic framework for operational semantics of membrane systems

Existing results in membrane computing refer mainly to P systems’ characterization of Turing computability, also to some polynomial solutions to NP-complete problems by using an exponential workspace created in a “biological way”. In this paper we define an operational semantics of a basic class of P systems, and give two implementations of the operational semantics using rewriting logic. We present some results regarding these implementations, including two operational correspondence results, and discuss why these implementations are relevant in order to take advantage of good features of both structural operational semantics and rewriting logic.     

Deduction, Strategies, and Rewriting

Automated deduction methods should be specified not procedurally, but declaratively, as inference systems which are proved correct regardless of implementation details. Then, different algorithms to implement a given inference system should be specified as strategies to apply the inference rules. The inference rules themselves can be naturally specified as (possibly conditional) rewrite rules. Using a high-performance rewriting language implementation and a strategy language to guide rewriting computations, we can obtain in a modular way implementations of both the inference rules of automated deduction procedures and of algorithms controling their application. This paper presents the design of a strategy language for the Maude rewriting language that supports this modular decomposition: inference systems are specified in system modules, and strategies in strategy modules. We give a set-theoretic semantics for this strategy language, present its different combinators, illustrate its main ideas with several examples, and describe both a reflective prototype in Maude and an ongoing C++ implementation.     

Invariant-driven specifications in Maude

This work presents a general mechanism for executing specifications that comply with given invariants, which may be expressed in different formalisms and logics. We exploit Maude’s reflective capabilities and its properties as a general semantic framework to provide a generic strategy that allows us to execute Maude specifications taking into account user-defined invariants. The strategy is parameterized by the invariants and by the logic in which such invariants are expressed. We experiment with different logics, providing examples for propositional logic, (finite future time) linear temporal logic and metric temporal logic.     

On Reachability and Spatial Reachability in Fragments of BioAmbients

BioAmbients is a powerful model for representing various aspects of living cells. The model provides a rich set of operations for the movement and interaction of molecules. The richness of the language motivates the study of dialects of the full model and the comparison with other computational models. In this paper we investigate the limit between decidability and undecidability of two decision problems, namely reachability and spatial reachability, for semantic and syntactic fragments of BioAmbients providing movement capabilities and merge. Our results illustrate the power of merge with respect to the other movement operations of BA for properties like reachability. Furthermore, they establish an interesting connection between BioAmbients and other computational models like associative-commutative term rewriting and Petri nets with transfer arcs.     

面向安全攸关系统中小概率事件的统计模型检测

在开放运行环境中,安全攸关系统的不确定性行为有可能导致小概率事件的发生,而此类事件的可靠性指标往往很高,小概率事件一旦发生就会产生灾难性的后果,严重威胁到人们的生命、财产安全.因此,评估、预测小概率事件发生的概率,对于提高系统的可靠性具有重要意义.统计模型检测是一种基于模拟的模型验证技术,结合了系统的快速模拟及统计分析技术,能够有效提高模型检测的效率,适用于验证、评估安全攸关系统的可靠性,但其面临的挑战性问题之一是在可接受的样本数量下,使用统计模型检测技术难以预测、评估小概率事件发生的概率.因此,提出一种改进的统计模型检测框架,设计和开发基于机器学习的统计模型检测器,实现在相对较少的样本数量下预测和评估小概率事件发生的概率.结合轨道交通控制系统中避碰控制案例分析,进一步证明改进后的统计模型检测器能够有效预测和评估安全攸关系统中小概率事件发生的概率.