On the Expressiveness of Context-Sensitive Graph Grammars

上下文相关图文法是描述可视化语言的形式化工具.为了直观地刻画并高效地分析可视化语言,已有图文法形式框架均着重于文法形式和分析算法的研究,而忽略了对它们之间表达能力的分析.在对已有上下文相关图文法形式框架的关键特征进行分析和归纳的基础上,通过构造不同形式框架之间的转换算法,揭示并形式化证明了它们表达能力之间的关系.而且,转换算法在不同形式框架之间建立了关联,使图文法的应用不必再局限于一个框架,而是可以选择不同框架分别进行图的描述和分析,从而提高了上下文相关图文法的易用性.     

上下文相关图文法的表达能力分析

上下文相关图文法是描述可视化语言的形式化工具.为了直观地刻画并高效地分析可视化语言,已有图文法形式框架均着重于文法形式和分析算法的研究,而忽略了对它们之间表达能力的分析.在对已有上下文相关图文法形式框架的关键特征进行分析和归纳的基础上,通过构造不同形式框架之间的转换算法,揭示并形式化证明了它们表达能力之间的关系.而且,转换算法在不同形式框架之间建立了关联,使图文法的应用不必再局限于一个框架,而是可以选择不同框架分别进行图的描述和分析,从而提高了上下文相关图文法的易用性.     

可视化语言技术在软件开发中的应用

可视化语言技术比一维文本语言在描述软件组成方面具有优越性.由于图表和图形概念在系统建模中的广泛使用,可视化语言可以应用于需求分析、设计、测试和维护等软件开发的各个阶段.除了具有直观易见的特点之外,图文法在计算机上的精确建模和验证能力,为设计可视化语言提供了一个坚实的理论基础.讨论了可视化语言的形式理论基础,回顾了相关的可视化图形编程环境.特别提出了一种空间图文法,并且用该图文法定义了统一建模语言的行为语义.基于空间图文法,开发了一种基于模式驱动的框架,以帮助软件架构与设计.     

属性文法中变元间的关系

本文从模式的语义、句法描述着眼,分析了一个属性文法的产生式变元间的几种关系,把 这些关系作为语义部分的内容,从而推广了属性文法,以推广后的属性文法为基础,引入控制 连接图作为主要的限制条件,提出一种"语义程序文法",并把标准模式与畸变模式之间的联系 用限制条件描述.最后利用变元间的关系,把模式的描述与知识的表达联系起来.     

含无序产生式的故事分析文法的研究

基于故事分析文法的故事理解法是本文作者在其博士论文中提出的一种面向故事深层含义的对语法、语义和语用综合进行理解的形式化方法，故事分析文法是一种高维的上下文有关文法，为了提高它的描述能力和表达范围，本文定义了一种特殊的产生式：无序产生式，并将它引入故事分析文法，讨论了由此带来的对故事分析文法的影响和无序产生式在故事分析文法中的性质，最后给出了含无序产生式的故事分析文法的一个子类文法的语法分析算法．     

基于容错Earley解析算法的领域语义文法自动学习方法

精细化的领域文本分析是高质量领域知识获取的重要前提,它通常依赖于大量某种形式的语义文法产生式,但总结这些文法通常耗时耗力.对此,文中提出了 一种基于容错Earley解析算法的语义文法自动学习方法,根据种子文法自动生成新的语义文法(包括词类和文法产生式),以减少人工成本.该方法利用优化后的容错Earley解析器,对输入的语句进行容错解析,然后根据容错解析生成的解析树产生候选语义文法,最后对候选语义文法进行过滤或纠正得到最终的语义文法.在5种不同疾病的中医医案的实验中,该方法的词类学习的正确率达到63.88％,文法产生式学习的正确率达到81.78％.     

Tabular表达式的指称语义研究

Tabular 表达式是一种采用表格化结构组织函数或关系的形式化描述工具,在需求工程领域中具有广泛的应用,为Tabular 表达式建立形式的语义模型是非常必要的.针对Tabular 表达式通用模型,给出了Tabular 表达式的形式文法及指称语义.通过定义形式文法中各语法单元的语义指派方程,描述了Tabular 表达式的指称语义,分别对传统类型Tabular 表达式和新类型Tabular 表达式中一些典型表类型的指称语义进行了描述,并与其他几种Tabular 表达式的语义描述方法进行了比较.分析结果表明：该语义描述方法不仅准确描述了Tabular 表达式的语义,而且不再受Tabular 表达式模型和Tabular 表达式类型的限制,打破了现有方法的局限性,是一种非常有效的方法.     

形式语义学发展简介

一.前言最近十年,形式描述和说明技术有了迅速发展。从对程序设计语言的形式描述来说,最初的一次正规、严格的形式描述是Algol 60的文法描述,接着 IBM 的研究人员对 PL/I 的文法和语义作了严格的形式描述,Wirth 也和 Hoare 合作对其杰作 PASCAL 语言作了公理化语义描述,目前又发表了对 Ada 的形式描述。形势是,一种程序语言的推出,若无严格的形式(文法与语义)定义,似乎无法叫人信赖。与此同时,对各     

并行性挖掘的图文法方法

并行性分析技术一般通过对程序的控制与数据流图或相关依赖图的分析来实现,因而需要从程序中抽取出相应依赖图的算法的支持.本文基于上下文相关图文法RGG形式框架,定义了一种任务级的并行编程图语言GPPL来直接描述顺序或并行程序的控制与数据流图,而且设计了相应的并行性分析算法以挖掘GPPL图程序的并行性特征.GPPL图语言可视为并行程序设计与程序代码生成之间的协同语言,从而使并行性挖掘避免了从程序中抽取出相应依赖图的过程.与已有的描述顺序或并行程序的图语言及其分析算法相比,GPPL图程序形式更为简洁和直观,易于设计,描述能力也更强;基于GPPL图的并行性分析算法的分析能力更强,而且具有可扩展性.     

转换文法与程序转换

本文提出一种新的语义描述文法——转换文法。使用这种转换文法,可以描述程序语言之间的形式转换。程序转换算法根据转换文法,可把源语言程序转换为目标语言程序。     

Parsing nonlinear languages

The diagrammatic approach to user interfaces for computer-aided software development toolkits, visual query systems, and visual programming environments, is based on the use of diagrams and charts traditionally drawn on paper. In particular, the VLG system (Visual Language Generator) has been proposed to generate icon-oriented visual languages customized for given applications. The syntactical model underlying the interpretation of a visual language in VLG has been designed to describe icon-oriented visual languages. In order to enable the VLG system to apply to any kind of graphical languages, like diagrammatic ones, it is necessary to find a more general syntactical model able to support both their generation and interpretation. This paper addresses the comprehension of the features that a grammatical formalism for nonlinear languages must have to match any requirement for an efficient parsing. To this aim, relation grammars support an easy implementation of a general parsing algorithm for multidimensional languages, parametric with respect to the rewriting rules of the grammar. We compare the expressive power of relation grammars to grammatical formalisms for graph grammars     

一种基于边的上下文相关图文法形式化框架

围绕解决图文法中的主要问题——嵌入问题,提出了一种基于边的上下文相关图文法形式化框架,并对由此定义的文法的一些性质及相应的归约算法进行了讨论.对所提出的图文法与已有的文法进行了比较.同时,展望了今后值得进一步研究的一些问题和方向.     

Meta-modelling and graph grammars for multi-paradigm modelling in AToM<Superscript>3</Superscript>

This paper presents the combined use of meta-modelling and graph grammars for the generation of visual modelling tools for simulation formalisms. In meta-modelling, formalisms are described at a meta-level. This information is used by a meta-model processor to generate modelling tools for the described formalisms. We combine meta-modelling with graph grammars to extend the model manipulation capabilities of the generated modelling tools: edit, simulate, transform into another formalism, optimize and generate code. We store all (meta-)models as graphs, and thus, express model manipulations as graph grammars.We present the design and implementation of these concepts in AToM³ (A_To_ol for M_ulti-formalism, M_eta-M_odelling). AToM³ supports modelling of complex systems using different formalisms, all meta-modelled in their own right. Models in different formalisms may be transformed into a single common formalism for further processing. These transformations are specified by graph grammars. Mosterman and Vangheluwe [18] introduced the term multi-paradigm modelling to denote the combination of multiple formalisms, multiple abstraction levels, and meta-modelling. As an example of multi-paradigm modelling we present a meta-model for the Object-Oriented Continuous Simulation Language OOCSMP, in which we combine ideas from UML class diagrams (to express the OOCSMP model structure), Causal Block Diagrams (CBDs), and Statecharts (to specify the methods of the OOCSMP classes). A graph grammar is able to generate OOCSMP code, and then a compiler for this language (C-OOL) generates Java applets for the simulation execution.     

Graph grammars with string-regulated rewriting

Multicellular organisms undergo a complex developmental process, orchestrated by the genetic information in their cells, in order to form a newborn individual from a fertilized egg. This complex process, not completely understood yet, is believed to have a key role in generating the impressive biotic diversity of organisms found on earth. Inspired by mechanisms of Eukaryotic genetic expression, we propose and analyse graph grammars with string-regulated rewriting. In these grammatical systems a genome sequence is represented by a regulatory string, a graph corresponds to an organism, and a set of graph grammar rules represents different forms of implementing cell division. Accordingly, a graph derivation by the graph grammar resembles the developmental process of an organism. We give examples of the concept and compare its generative power to the power of the traditional context-free graph grammars. We demonstrate that the power of expression increases when genetic regulation is included in the model, as compared to non-regulated grammars. Additionally, we propose a hierarchy of string-regulated graph grammars, arranged by expressive power. These results highlight the key role that the transmission of regulatory information during development has in the emergence of biological diversity.     

上下文相关图文法分析及其应用初探

图文法是一种对可视化语言进行形式化定义的元语言，具有表达自然、能力强大的特点.随着使用可视化语言的最终用户编程技术的广泛应用，图文法分析尤其是上下文相关图文法分析在工程应用中的重要性日益突出.国内外相关文献或着重于纯理论探讨，或局限于特定语法类的特定应用，不利于工程应用人员参考.本文选取简洁明了的符号体系，介绍上下文相关图文法分析的一般性过程，并将其中规则选取关键步骤描述为CSP问题，利用已有的针对CSP问题的优化方法来优化算法，介绍了现有的优化方法并给出实现算法;同时，结合自身实践，讨论其在一个面向体系结构的Web服务集成系统中的应用.     

Defining the abstract syntax of visual languages with advanced graph grammars—A case study based on behavior trees

Diagrammatic visual languages can increase the ability of engineers to model and understand complex systems. However, to effectively use visual models, the syntax and semantics of these languages should be defined precisely. Since most diagrammatic visual models that are currently used to specify systems can be described as (directed) typed graphs, graph grammars have been identified as a suitable formalism to describe the abstract syntax of visual modeling languages. In this article, we investigate how advanced graph-transformation techniques, such as conditional, structure-generic and type-generic graph-transformation rules, can help to improve and simplify the specification of the abstract syntax of a visual modeling language. To demonstrate the practicability of an approach that unifies these advanced graph-transformation techniques, we define the abstract syntax of behavior trees (BTs), a graphical specification language for functional requirements. Additionally, we provide a translational semantics of BTs by formalizing a translation scheme to the input language of the SAL model checking tool for each of the graph-transformation rules.     

Expressive Completeness of Duration Calculus

This paper compares the expressive power of first-order monadic logic of order, a fundamental formalism in mathematical logic and the theory of computation, with that of the propositional version of duration calculus (PDC), a formalism for the specification of real-time systems. Our results show that the propositional duration calculus is expressively complete for first-order monadic logic of order. Our semantics for PDC conservatively extends the standard semantics to all positive (including infinite) length intervals. Hence, in view of the expressive completeness, liveness properties can be specified in PDC. This observation refutes a widely believed misconception that the duration calculus cannot specify liveness properties.