用于验证多智能体系统的APTL模型检测器

由于经典的线性时序逻辑表达能力有限,设计并开发了基于交替投影时序逻辑（alternating projection temporal logic,简称APTL）的模型检测工具.根据王海洋等人提出的APTL符号模型检测方法,设计并实现了APTL模型检测器MCMAS_APTL.该工具可用于多智能体系统（multi-agent system,简称MAS）的性质验证.MCMAS_APTL检查MAS是否满足具体性质的过程如下：首先,用解释系统编程语言（interpreted system programming language,简称ISPL）描述要验证的系统IS,用APTL公式P描述要验证的性质;然后,符号化表示系统IS,并将非P转化为范式;最后,计算所有满足非P的路径的起始状态集合.如果得到的状态集合中包含系统的初始状态,则说明系统不满足公式P;反之,则说明系统满足公式P.详细阐述了实现MCMAS_APTL的过程,并且通过验证机器人足球赛的例子展示了MCMAS_APTL的性能.     

一个命题投影时序逻辑符号模型检测器

现有模型检测工具的形式化规范语言,如计算树逻辑(computation tree logic,简称CTL)和线性时序逻辑(linear temporal logic,简称LTL)等的描述能力不足,无法验证ω正则性质.提出了一个命题投影时序逻辑(propositional projection temporal logic,简称PPTL)符号模型检测工具——PLSMC(PPTL symbolic model checker)的设计与实现过程.该工具基于著名的符号模型检测系统NuSMV,实现了PPTL的符号模型检测算法.PLSMC的规范语言PPTL具有完全正则表达能力,这使得定性性质和定量性质均可被验证.此外,PLSMC可以有效地缓解模型检测工具中容易发生的状态空间爆炸问题.最后,利用PLSMC对铁路公路交叉道口护栏控制系统的安全性质和周期性性质进行验证.实验结果表明,PPTL符号模型检测工具扩充了NuSMV系统的验证能力,使得时间敏感、并发性和周期性等实时性质可以被描述和验证.     

基于命题投影时序逻辑的单调速率调度算法模型检测

提出了基于命题投影时序逻辑(propositional projection temporal logic,简称PPTL)的单调速率调度(rate monotonic scheduling,简称RMS)模型检测方法.该方法使用SPIN模型检测器的系统建模语言PROMELA为任务调度系统建模,使用PPTL描述系统期望的性质,通过SPIN验证系统模型是否满足性质,从而得知一个任务组在RMS下是否可调度.同时,RMS算法控制下的任务调度系统的其他性质也可以得到验证.     

新型属性图文法反应式规约验证方法

属性图文法广泛应用在软件设计阶段建模和分析阶段。命题式时序逻辑（propositional temporal logic）无法直接表达建模实体包含随时间演化的关联属性反应式规约,提出一种可支持通用图文法转换系统中相应规约的验证方法,通过引入标记节点及属性,将包含相应关联属性的规约公式等价转换为命题式时序逻辑,从而可以间接支持该类型规约的验证。以流行的对象式属性图文法模型检测工具GROOVE为平台,结合启发案例,验证了所提出方法的有效性。     

ETL的符号化模型检验

为使符号化模型检验技术适用于全部ω-正规性质,研究了ETL(extended temporal logic)的符号化模型检验方法.首先,扩展了LTL(linear temporal logic)的Tableau方法,给出了ETL的Tableau构造方法,进而给出了该方法基于BDD(binary decision diagram)的符号化实现.同时,在NuSMV的基础上实现了支持ETL符号化验证的模型检验工具ENuSMV.该工具允许用户自定义时序连接子,从而可以检验全部ω-正规性质.实验结果表明,ETL性质能够被高效地采用符号化技术加以检验.     

基于线性时序逻辑的实时系统模型检查

模型检查是一种用于并发系统的性质验证的算法技术.LTLC(linear temporal logic with clocks)是一种连续时间时序逻辑,它是线性时序逻辑LTL的一种实时扩充.讨论实时系统关于LTLC公式的模型检查问题,将实时系统关于LTLC公式的模型检查化归为有穷状态转换系统关于LTL公式的模型检查,从而可以利用LTL的模型检查工具来对LTLC进行模型检查.由于LTLC既能表示实时系统的性质,又能表示实时系统的实现,这就使得时序逻辑LTLC的模型检查过程既能用于实时系统的性质验证,又能用于实时系统之间的一致性验证.     

带有时钟变量的线性时序逻辑与实时系统验证

为了描述实时系统的性质和行为,10多年来,各种不同的时序逻辑,如Timed Computation Tree Logic,Metric Interval Temporal Logic和Real-Time Temporal Logic等相继提出来.这些时序逻辑适于表示实时系统的性质和规范,但不适于表示实时系统的实现模型.这样,在基于时序逻辑的实时系统的研究中,系统的性质和实现通常是用两种不同的语言来表示的.定义了一个带有时钟变量的线性时序逻辑(linear temporal logic with clocks,简称LTLC).它是由Manna和Pnueli提出的线性时序逻辑在实时情况下的一个推广.LTLC既能表示实时系统的性质,又能很方便地表示实时系统的实现.它能在统一的语义框架中表示出从高级的需求规范到低级的实现模型之间的不同抽象层次上的系统描述,并且能用逻辑蕴涵来表示不同抽象层次的系统描述之间的语义一致性.LTLC的这个特点将有助于实时系统的性质验证和实时系统的逐步求精.     

面向事件图和事件时态逻辑的模型检验方法

针对目前没有适合直接对事件图模型进行性质规约的时态逻辑语言,提出一种基于事件的时态逻辑(event temporal logic,简称ETL).ETL以事件作为原子命题,根据事件图的特点增加了对事件取消操作、模型实例化、时间约束和同时事件优先级的表达能力,便于仿真领域的用户在模型检验过程中简洁地对基于事件图的模型应满足的性质进行描述.然后,在ETL公式和自动机理论的基础上,给出了面向事件图和ETL的模型检验方法来判断事件图模型是否满足ETL描述的性质规约.实例验证了ETL对事件图模型具有足够的表达能力以及该方法的有效性.     

基于直觉模糊集的不确定时序逻辑模型

针对现有时序逻辑在描述复杂不确定时间信息方面的局限性,提出了一种基于直觉模糊集的不确定时序逻辑模型。该模型分别定义了离散论域和连续论域下的不确定点时序逻辑、点-时段时序逻辑以及时段时序逻辑的判定公式;引入直觉模糊集的犹豫度参数,使得推理结果更加精确。最后通过实例对两类不确定时间信息进行描述,并对其时序逻辑关系的可能性进行度量。通过分析表明该模型是比较优越的。     

行为时序逻辑与自反线性时序逻辑的关系

为了能够将哲学逻辑中的公理系统运用到行为时序逻辑的研究中。对行为时序逻辑公式的语义进行形式化定义．从语义和语法两方面研究行为时序逻辑公理系统和具有自反性质的线性时序逻辑公理系统之间的联系．提出并证明行为时序逻辑公式转换为自反线性时序逻辑公式的定理。按照集合论和模型论的思想,定义行为时序逻辑中项和行为时序逻辑原子公式的概念。定义Lesilie Lamport所提出的行为时序逻辑公式的语义。证明自反线性时序逻辑公理系统适用于行为时序逻辑公理系统．以此为基础证明行为时序逻辑的简单规则、基本规则和附加规则。     

ITL semantics of composite Petri nets

interval temporal logic (itl) and Petri nets are two well developed formalisms for the specification and analysis of concurrent systems. itl allows one to specify both the system design and correctness requirements within the same logic based on intervals (sequences of states). As a result, verification of system properties can be carried out by checking that the formula describing a system implies the formula describing a requirement. Petri nets, on the other hand, have action and local state based semantics which allows for a direct expression of causality aspects in system behaviour. As a result, verification of system properties can be carried out using partial order reductions or invariant based techniques. In this paper, we investigate a basic semantical link between temporal logics and compositionally defined Petri nets. In particular, we aim at providing a support for the verification of behavioural properties of Petri nets using methods and techniques developed for itl.     

On the Construction of Monitors for Temporal Logic Properties

Temporal logic is a valuable tool for specifying correctness properties of reactive programs. With the advent of temporal logic model checkers, it has become an important aid for the verification of concurrent and reactive systems. In model checking the temporal logic properties are verified against models expressed in the tool's modelling language. In addition, model-checking techniques are useful to test actual implementations or to verify models of the system that are too detailed to be analysed by a model checker, by means of, for instance, simulation.A tableau construction is an algorithm that translates a temporal logic formula into a finite-state automaton that accepts precisely all the models of the formula. It is a key ingredient to checking satisfiability of a formula as well as to the automata-theoretic approach to model checking. An improvement to the efficiency of tableau constructions has been the development of on-the-fly versions.In this paper, we present a particular tableau construction for the incremental analysis of execution traces during test, simulation or model-checking. The automaton forms the basis of a monitor that detects both good and bad prefix of a particular kind, namely those that are informative for the property under investigation. We elaborate on the construction of the monitor and demonstrate its correctness.     

A user-friendly interface to specify temporal properties of concurrent systems

In model checking environments, system requirements are usually expressed by means of temporal logic formulas. We propose a user-friendly interface (UFI) with the aim of simplifying the writing of concurrent system properties. The tool is endowed with a graphical interface that supplies a set of patterns from the natural language; the defined patterns constitute a logic (UFL) that is adequate to express the classes of properties usually checked on actual systems. Moreover, UFI is integrated with the CWB-NC tool-kit which is a verification environment based on process algebras and the mu-calculus temporal logic; UFI supports the automatic translation of UFL formulas into mu-calculus formulas and save the translation in the format required by the CWB-NC. Nevertheless, UFI is a flexible tool that can be easily integrated with other environments.     

Model-based Runtime Verification Framework for Self-optimizing Systems

This paper describes a novel on-line model checking approach offered as service of a real-time operating system (RTOS). The verification system is intended especially for self-optimizing component-based real-time systems where self-optimization is performed by dynamically exchanging components. The verification is performed at the level of (RT-UML) models. The properties to be checked are expressed by RT-OCL terms where the underlying temporal logic is restricted to either time-annotated ACTL or LTL formulae. The on-line model checking runs interleaved with the execution of the component to be checked in a pipelined manner. The technique applied is based on on-the-fly model checking. More specifically for ACTL formulae this means on-the-fly solution of the NHORNSAT problem while in the case of LTL the emptiness checking method is applied.     

反应系统的连续时序逻辑表示和验证

引进一个称为LTLC的连续时间时序逻辑，用来对反应系统进行规范与验证．LTLC的一个重要特点是它能在统一的逻辑框架下表示反应系统及其性质，这样就可将系统与性质问的满足关系转化为逻辑公式间的蕴涵关系．同时，采用非负实数集作为时间域还使我们可以利用标准的存在量词来表示变量隐藏，并可用逻辑蕴涵来表示反应系统间的求精关系．该文首先给出了LTLC的一个简单介绍，然后讨论了如何使用LTLC对反应系统进行表示与推理，最后证明了一个关于LTLC的可判定性结果．此结果可用于有穷状态反应系统的自动验证．     

Verifying specifications in the language L against temporal properties nonexpressible in this language

Verification methods for reactive algorithms specifications in the language L are considered. The verification is performed with respect to properties expressed in the class GR(1) of the temporal logic LTL and is reduced to checking the satisfiability of formulas in the language L.     

LORETO: a tool for reducing state explosion in verification of LOTOS programs

LOTOS is a formal specification language for concurrent and distributed systems. Basic LOTOS is the version of LOTOS without value‐passing. A widely used approach to the verification of temporal properties is model checking. Often, in this approach the formal specification is translated into a labeled transition system on which formulae expressing properties are checked. A problem with this verification technique is state explosion: concurrent systems are often represented by automata with a prohibitive number of states. In this paper we show how, given a set ρ of actions, it is possible to automatically obtain for a Basic LOTOS program a reduced transition system to which only the arcs labeled by actions in ρ belong. The set ρ of actions plays a fundamental role in conjunction with a temporal logic defined by the authors in a previous paper: selective mu‐calculus. The reduced system with respect to ρ preserves the truth value of all selective mu‐calculus formulae with actions from the set ρ. We act at both syntactic and semantic levels. From a syntactic point of view, we define a set of transformation rules obtaining a smaller program. On the semantic side, we define a non‐standard semantics which dynamically reduces the transition system during generation. We present a tool implementing both the syntactic and the semantic reduction. Copyright © 1999 John Wiley & Sons, Ltd.     

Game-theoretic simulation checking tool

Model checking is one of the most commonly used methods for checking program correctness. In this method, one verifies a program model given by the Kripke structure (labeled transition system) rather than the program itself. The specification is usually given as a temporal logic formula. In many subtasks of model checking, it is necessary to use relations that are defined on the set of program models and preserve the satisfiability of temporal logic formulas. There exist many relations of this kind, which are called simulation relations. In the present paper, we introduce a tool designed to check a wide class of simulation relations between finite models of programs. This tool is based on the simulation checking game-theoretic approach. The tool consists of two components. The first component is the formal language, which allows one to define various simulation relations in terms of an antagonistic two-player game. The second component is a software tool that, given two labeled transition systems and simulation definition, is able to check whether this simulation is satisfied between these labeled transition systems.     

Verification of external specifications of reactive systems

External specification is currently approached by specification languages for describing and analyzing system requirements. The external specification can be defined during the early stages of the system development and can be very useful for: checking the class/system/subsystem requirements; checking the system composition; evaluating costs of reuse; defining validated reference requirements, histories, and traces for the final validation. The paper presents a collection of criteria in order to formally verify the external specification of reactive systems/subsystems. The verification criteria are grounded on the Tempo Reale object-oriented language (TROL) specification model for real-time systems. In TROL, the external specification is expressed in terms of ports and clauses with temporal constraints. The goal of the verification criteria presented is to check the completeness and consistency of the external specification with special attention to temporal constraints. These criteria can be applied to other real-time specification models and have been enforced in the tool object oriented machine state (TOOMS) tool. A practical example illustrates the verification process that embodies these criteria