基于GoGCN的软件系统类交互关系预测

软件系统是一个复杂的人工制品,类之间的交互关系对软件质量有着潜在影响,如软件缺陷的级联传播效应就是一个典型.如何准确预测软件系统中类之间合理关系,优化设计结构是软件质量保障的一个开放问题.从软件网络观的视角,综合考虑软件系统中类与类之间关系(外部图),以及每个类内部方法之间关系(内部图),将软件系统抽象成一个图中图结构的软件网络,并在此基础上提出一种基于图中图卷积神经网络的类交互关系预测方法.首先对每个类内部图进行卷积得到类节点的初始特征,再通过外部图的卷积更新类节点的表征向量,最后通过计算类节点对的评估值进行交互预测.根据在6个Java开源项目上的实验结果显示,图中图结构有助于提高软件系统结构的表征能力,且所提方法与常规网络嵌入方法相比, AUC值和AP值的平均增长率超过5.5%.与此同时,和两种同行方法相比, AUC值和AP值的平均增长率分别在9.36%和5.22%以上.     

On the equivalence and range of applicability of graph-based representations of logic programs

Logic programs under Answer Sets semantics can be studied, and actual computation can be carried out, by means of representing them by directed graphs. Several reductions of logic programs to directed graphs are now available. We compare our proposed representation, called Extended Dependency Graph, to the Block Graph representation recently defined by Linke [Proc. IJCAI-2001, 2001, pp. 641-648]. On the relevant fragment of well-founded irreducible programs, extended dependency and block graph turns out to be isomorphic. So, we argue that graph representation of general logic programs should be abandoned in favor of graph representation of well-founded irreducible programs, which are more concise, more uniform in structure while being equally expressive.     

The analysis and partial synthesis of truss structures via theorem proving

A use of theorem proving for the analysis and partial synthesis of truss structures is presented. The behavior of a truss structure is modeled as the set union of the behavior of its constituent components where the behavior of each component is modeled by a set of constraints. This component/constraint model is formally represented by a set of axioms using predicate logic. The axioms are then used toanalyze and partiallysynthesize truss structures via theorem proving.Constraint logic programming is identified as a suitable implementation vehicle for the analysis and partial synthesis of truss structures via theorem proving. Several important implications of the formulation for structural design automation, data base integrity, and parallel processing are discussed.     

Qualitative behavioral reasoning from components’ interfaces to components’ functions for DMU adaption to FE analyses

A digital mock-up (DMU), with its B-Rep model of product components, is a standard industrial representation that lacks geometric information about interfaces between components. Component shapes reflect common engineering practices that influence component interfaces with interferences and not only contacts.The proposed approach builds upon relationships between function, behavior, and shape to derive functional information from the geometry of component interfaces. Among these concepts, the concept of behavior is more difficult to set up and connect to the geometry of interfaces and functions. Indeed, states and design rules are introduced to express the behavior of components through a qualitative reasoning process. This reasoning process, in turn, takes advantage of domain knowledge rules and facts, checking the validity of certain hypotheses that must hold true all along a specific state of the product’s lifecycle, such as operational, stand-by or relaxed states. Eliminating configurations that contradict one or more of those hypotheses in their corresponding reference state reduces ambiguity, subsequently producing functional information in a bottom-up manner.This bottom-up process starts with the generation of a conventional interfaces graph (CIG) with components as nodes, and conventional interfaces (CIs) as arcs. A CI is initially defined by a geometric interaction that can be a contact or an interference between two components. CIs are then populated with functional interpretations (FIs) according to their geometric properties, producing potentially many combinations. A first step of the reasoning process, the validation against reference states, reduces the number of FIs per CI.Domain knowledge rules are then applied again to group semantics of component interfaces into one functional designation per component to connect together geometric entities of its boundary with its function.     

对逻辑覆盖软件测试准则的公理化评估

由于形式规格说明采用一种精确、一致、容易被机器自动处理的符号系统来描述软件需求,因而形式规格说明为测试用例的自动生成和软件功能的验证提供了基础.在基于形式规格说明的测试过程中逻辑覆盖测试准则是一组常用的测试准则,如何选择和使用其中的每个测试准则是应用这组测试准则时面临的主要问题.因此分析和比较这组测试准则中每个测试准则的性质将为测试工程师选择测试准则提供指导和帮助.对测试充分性准则的公理化评估是一种比较测试准则的方式,这种方式将对理想的测试准则的直觉需求定义为一组公理,然后通过检查测试准则是否满足该组公理来分析和比较相应的测试准则.描述了一组理想的逻辑覆盖测试准则应该具有的性质和用来确定一个测试充分性准则是否完全的生成算法.这组性质被形式化地定义为一组公理.利用这种形式化的定义,用定理的形式精确地给出了这些性质之间的关系.最后通过这组公理系统来评估现有的逻辑覆盖测试准则.评估的结果为测试人员在实际过程中选择逻辑覆盖测试准则提供了指导.     

Slicing Software for Model Construction

Applying finite-state verification techniques (e.g., model checking) to software requires that program source code be translated to a finite-state transition system that safely models program behavior. Automatically checking such a transition system for a correctness property is typically very costly, thus it is necessary to reduce the size of the transition system as much as possible. In fact, it is often the case that much of a program's source code is irrelevant for verifying a given correctness property.In this paper, we apply program slicing techniques to remove automatically such irrelevant code and thus reduce the size of the corresponding transition system models. We give a simple extension of the classical slicing definition, and prove its safety with respect to model checking of linear temporal logic (LTL) formulae. We discuss how this slicing strategy fits into a general methodology for deriving effective software models using abstraction-based program specialization.     

构件软件变更风险分析技术

构件软件相较于传统软件系统有更快的演化速度,对其变更进行有效的度量将有利于后期的维护活动.本文分别针对代码可见及不可见两种类型的构件,运用改进的构件依赖图建模,表示构件软件系统.分两步分析构件变更所带来的风险:首先在计算变更比例的基础上度量单个构件的变更风险,再通过将构件依赖图转化成构件依赖树来计算变更的构件集给系统所带来的风险.此外,结合实例系统的分析给出了所提出的变更风险度量的若干性质.     

一种软构件依赖关系的拓扑布局算法

本文提出了一种圆环型的有向图拓扑布局算法,能够清晰地展示软构件之间的相互依赖关系,有助于设计人员更好地理解和分析多构件系统中构件间依赖关系的整体态势,进而优化系统结构,提高系统性能,实现高效的软构件组装。     

A graphical approach to relational reasoning

Relational reasoning is concerned with relations over an unspecified domain of discourse. Two limitations to which it is customarily subject are: only dyadic relations are taken into account; all formulas are equations, having the same expressive power as first-order sentences in three variables. The relational formalism inherits from the Peirce-Schröder tradition, through contributions of Tarski and many others.Algebraic manipulation of relational expressions (equations in particular) is much less natural than developing inferences in first-order logic; it may in fact appear to be overly machine-oriented for direct hand-based exploitation.The situation radically changes when one resorts to a convenient representation of relations based on labeled graphs. The paper provides details of this representation, which abstracts w.r.t. inessential features of expressions.Formal techniques illustrating three uses of the graph representation of relations are discussed: one technique deals with translating first-order specifications into the calculus of relations; another one, with inferring equalities within this calculus with the aid of convenient diagram-rewriting rules; a third one with checking, in the specialized framework of set theory, the definability of particular set operations. Examples of use of these techniques are produced; moreover, a promising approach to mechanization of graphical relational reasoning is outlined.     

软件构架动态行为建模与检测

针对软件构架描述语言在分析、验证软件构架动态行为中的不足,用抽象代数对构件、连接器和体系结构配置进行抽象,提出了软件构架层次模型,并采用Pr／T网对软件构架动态行为建模．提出基于线性时序逻辑的软件构架动态行为模型检测方法,给出了该方法的算法描述．最后,详细描述了电子商务系统中并发控制机制的建模过程和检测结果．提出的软件构架动态行为建模与检测方法结合了Pr／T网和线性时序逻辑的优点,为开展软件构架动态行为的分析、验证提供了理论基础．     

基于图的谱分割技术的面向对象软件系统分解*

主要是以一种带权类依赖图作为面向对象系统的UML类图的抽象表示,其中类依赖图的各边上权值对应于类图中的相应关系。针对带权类依赖图运用代数图论中图的Laplace谱的连通特性以迭代分割的方式对其进行划分,得到所需开发的系统构件。通过实验表明,该方法是一种有效的面向对象软件系统分解方法,并且分解所得到的构件具有较高的内聚性。     

面向对象的动态图编辑器的设计与实现

提出了一种面向对象的动态图编辑器,该动态图编辑器区别一般图编辑器的方面在于：可以根据用户的需要在任何时候动态地执行用户程序定义的方法;产生可序列化的图;编辑部分和显示部分既能合并使用也能分开使用;允许用户定义任意形状的结点和弧;具有处理无向图和有向图的双重功能。用户可以分别利用交互式编辑环境和图布局机制输入小型图和中、大型图。动态图编辑器体系结构建立在软件工程设计模式和面向对象设计思想的基础上,用ＪＡ－ＶＡ２实现。     

基于图文法的动态软件体系结构支撑环境

使用类型化的属性图及其图文法来直观而形式地刻画软件体系结构和体系结构风格,用图转换来刻画动态体系结构的重配置行为.基于这种刻画,构建了一个动态软件体系结构支撑环境.该环境一方面,通过一个基于图文法的编辑器来支持体系结构图模型的可视化构造和操纵;另一方面,基于内置运行时体系结构技术实现了体系结构图模型在具体系统中的物理实施,并使得图模型上的图转换操作可以自动映射到实际系统的动态重配置上.再加上一系列的辅助设施,形成了一个较为完整的基于图文法的动态软件体系结构支撑环境.     

Monitoring dynamic integrity constraints based on temporal logic

Dynamic integrity constraints are used to specify admissible sequences of database states. We present algorithmic fundamentals of monitoring constraints expressed in temporal logic. The essential means are finite transition graphs which can be constructed from temporal formulae by utilizing an appropriate normalform. To ensure admissibility of a state sequence, the integrity monitor has to follow a corresponding path through the graph and to check certain nontemporal conditions in each state; these conditions are provided as edge labels. Thus, monitoring dynamic integrity is reduced to a controlled checking of static integrity. All errors in present database behaviour are detected as well as many inevitable future errors.     

并行软件模型检测

并行化是提高模型检测效率的重要手段。该文研究了基于标号迁移系统的C程序模型检测,提出一种软件模型检测并行化的方法。该方法利用软件模型检测工具模块化验证(MAGIC)的模块化特性对C程序进行组件分解,将各组件均衡地分发到若干计算节点,由节点调用MAGIC完成验证。由于保证节点间只有少量的通信与同步,该方法能达到较好的并行加速比,具有良好的可扩展性。实验结果显示,该方法大幅压缩了检测时间,有利于大规模软件的形式化验证。     

事件触发下多智能体系统固定时间二分一致性

针对具有符号有向图的一阶多智能体系统,研究了其固定时间二分一致性问题。为降低控制过程中多智能体系统的能量损耗,提出了一种基于事件触发机制的分布式控制协议。以图论和李雅普诺夫理论为主要研究工具,给出了多智能体系统在所设计控制协议作用下实现固定时间二分一致性的充分条件和与系统初始状态无关的收敛时间上界,并证明了使用该协议可以有效避免对智能体的连续控制和Zeno行为的发生。数值算例验证了所得理论结果的有效性。     

Copying Errors in Object-Oriented Design

This paper presents a solution to an integration problem arising when copying (reusing) software components developed for one domain into software structures in a similar domain. This particular problem has not been previously addressed in the design of object-oriented languages whose intent is to enhance software reuse and software integration. Object structures are directed graphs where edges are either inheritance or client- server associations, and nodes are abstract data types. The formal logic for abstract data types used in the formal method is first-order predicate logic, and the proof system uses natural deductive logic. This is the background formal logic system, and the semantic part of each object definition uses this logic. A solution to the copyability problem is presented using the new properties of inheritance relation in copyable and out copyable, as well as client-server fan in copyable and fan out copyable. This solution to the copyability problem is presented by means of an effective method using a framework for identifying and assessing potential errors in a given object- oriented structure. Several different kinds of formal logic errors are identified which can occur during copying of object definitions represented as abstract data types into object-oriented structures.     

Connective fault tolerance in multiple bus systems

We present an efficient approach to characterizing the fault tolerance of multiprocessor systems that employ multiple shared buses for interprocessor communication. Of concern is connective fault tolerance, which is defined as the ability to maintain communication between any two fault-free processors in the presence of faulty processors, buses, or processor-bus links. We introduce a model called processor-bus-link (PBL) graphs to represent a multiple-bus system's interconnection structure. The model is more general than previously proposed models, and has the advantages of simple representation, broad application, and the ability to model partial bus failures. The PBL graph implies a set of component adjacency graphs that highlights various connectivity features of the system. Using these graphs, we propose a method for analyzing the maximum number of faults a multiple-bus system can tolerate, and for identifying every minimum set of faulty components that disconnects the processors of the system. We also analyze the connective fault tolerance of several proposed multiple-bus systems to illustrate the application of our method     

面向构件化软件的合约检查测试框架

基于构件软件开发的主要思想是使用现存的构件来建构软件系统。而这样的系统由于构件本身的特点导致了许多测试困难。B. Meyer将构件与其客户代码之间的关系形式化地定义为一种合约,它严格限定了构件对象之间的交互规则。通过对合约的监视和检查,可以容易地发现构件之间的交互错误,从而达到集成测试构件化软件的目的。该文提出了一种基于合约检查的构件集成测试框架 (contract-checking test framework,CCTF)。讨论了该框架合约检查的思想、5大功能模块以及其测试流程,并介绍了将CCTF应用到构件化软件测试平台实现的一些关键技术。