一种基于模糊概念格和代码分析的软件演化分析方法

软件系统的演化分析是程序分析和程序理解的一个重要方面.通过演化分析可以了解系统需求和设计的演化趋势,从而更好地理解系统的需求和设计决策.文中在前期工作所提出的基于模糊概念格的程序分析方法基础上,进一步将其用于系统演化分析,提出了一种基于模糊概念格的软件演化分析方法.该方法利用基于概念相似度度量的松弛树匹配的方法建立不同版本概念格中概念和概念子格之间的映射关系,在此基础上通过结构差异分析来发现各种演化类型.实验表明,该方法能够有效地发现不同版本之间的高层演化信息,有助于开发人员理解系统的演化历史以及相关的设计决策.     

面向开源软件的演化确认方法

软件演化确认是软件工程领域的一个重点和热点的研究方向。由于开源软件具有群智开发,演化过程不可控和不可建模等特点,使得传统的确认方法不适合于开源软件,故从功能语义角度提出了一种软件演化确认方法,试图将代码按主题的方式进行聚类,每一个主题表征软件系统的一个功能集合,演化确认工作被转化为功能集合与演化需求之间的映射关系。通过对现有开源软件的源代码进行实验,获取了大量的真实可靠实验数据,对这些实验数据进行分析后得出的实验结果表明该方法相较基于文本的基线方法,更能有效区分是否已经演化,可以用于对软件演化进行确认工作。     

基于UML实时系统的分析和设计

介绍了统一建模语言的最新版本UML2及应用UML2进行实时系统设计的作用及意义.探讨了UML2中用在实时系统设计中的概念.结合一个使用UML2为家庭安全系统设计的例子,着重分析了系统的静态结构和动态行为,通过类图、顺序图、状态图等UML图描述系统的方法从整体上对系统建模,说明实时系统分析与设计过程.使用UML分析和设计系统能够提高软件设计的效率和质量增强软件的维护性和复用性.     

元胞自动机的演化行为研究*

基于元胞自动机演化行为研究与仿真系统,通过对元胞自动机的一、二、三维演化行为的研究,从统计和渐进的角度对元胞自动机进行了分类,将元胞自动机的演化行为动态统计图与沃尔弗拉姆对于元胞自动机的分类对应起来研究.这些从不同视角得到的结果有助于对元胞自动机的演化行为进行深入研究;但从统计和渐进的角度对元胞自动机进行分类是否具有普适性,是需要进一步研究探讨的问题.     

一种基于动作语义的UML1.X-2.0模型转换方法

虽然UML2.0标准被OMG组织采纳已久,但由于UML1.X标准在工业界的广泛使用,仍然存在大量的实用模型和应用软件,它们在UML2.0标准之下已不能准确描述系统.UML2.0建模工具并不支持从UML1.X模型到UML2.0模型的转换.从顶层元模型的角度比较了这两个版本的不同,采用声明式和命令式混合的模型框架,给出了一种基于动作语义的UML模型转换方法,并用ASL描述交互元模型的转换实例,验证了方法的可行性.该方法将减少用户的重复劳动,实现软件的模型重用,也适用于其他元模型或模型层次上的转换.     

演化算法中一种基于单分类的预选择策略

演化算法中,预选择算子用于为后续的环境选择过程筛选出好的潜在候选后代解.现有预选择算子大多基于适应值评估、代理模型或分类模型.由于预选择过程本质上是一个分类过程,因此基于分类的预选择过程天然适用于演化算法.先前研究工作采用二分类或多分类模型进行预选择,需预先准备“好”和“差”两组或具有区分性的多组训练样本来构建分类模型,而随着演化算法的执行,“好”解和“差”解之间的界限将愈加模糊,因此准备具有区分性的两组或多组训练样本将变得具有挑战性.为解决该问题,本文提出了一种基于单分类的预选择策略(One-class Classification based PreSelection,OCPS),首先将当前种群中的解均视为“好”类样本,之后只利用该类“好”样本构建单分类模型,然后利用构建的模型对产生的多个候选解进行标记与选择.提出的策略应用在三个代表性演化算法中,数值实验结果表明,提出的策略能够提升现有演化算法的收敛速度.     

基于版本间克隆映射的演化模式识别及谱系构建

针对当前克隆谱系的构建方法较为复杂、演化模式亟需扩充等问题,提出了新的克隆代码演化模式,并根据软件版本间的克隆代码映射关系自动构建了克隆谱系。首先,针对软件每一版本进行克隆检测并利用潜在狄利克雷分配（LDA）抽取克隆代码的主题信息;然后,根据克隆代码主题的相似度确定版本间克隆代码的映射关系;进而,根据已有的映射关系为克隆代码添加演化模式并分析演化特征;最终,结合映射信息与演化模式信息完成克隆谱系的构建。针对4款开源软件进行了克隆谱系的构建实验,实验结果表明所提克隆谱系构建方法可行,证实了新提出的演化模式在克隆代码演化过程中确实存在。实验发现约90%的克隆代码在软件演化过程中比较稳定,约67%的克隆群经历的发布版本数不超过发布版本总数的一半。实验结论及理论分析将为克隆代码的后续研究及克隆代码的维护与管理提供有力支持。     

基于变化的服务演化一致性判定

由于Web服务处在开放、动态、多变的网络环境下,为了有效响应用户需求、运行平台及外部环境的变化,服务必须具备演化的能力。演化后的服务应维持与原伙伴服务或服务用户之间的正常交互,这种性质称为演化一致性。由于Web环境的多样性,服务开发者对演化一致性的判定的标准并不统一。对于服务演化一致性判定问题,现有方法大多基于固定的判定标准,缺乏可调节、细粒度的定量分析且不能显式地反映服务版本之间的变化。针对上述不足,面向服务演化导致的变化,从服务的结构层和非功能层两个角度建立基于变化的服务描述模型,并在该模型的基础上引入演化一致度对演化一致性进行度量。基于所提出的方法,设计并实现了一个服务演化一致性判定工具,验证了所提出方法的可行性与有效性。     

基于软件代码演化信息的克隆谱系提取方法

针对现有克隆演化模式分类不清晰、克隆谱系提取工具少且效率低等问题,提出了根据克隆代码映射关系和演化信息自动构建克隆谱系的方法。首先通过词频向量计算、代码行距以及克隆属性相结合分阶段映射版本间克隆;然后根据映射结果为克隆群和克隆片段添加演化模式;最后串联所有版本中的克隆映射关系和演化模式构建克隆谱系。对4款开源软件进行实验并人工验证,实验结果表明克隆谱系提取工具——ECG的可行性和高效性。此外,从提取结果中发现,在演化过程中约42%的克隆代码未发生变化,发生不一致变化的克隆代码约占3.48%,此类克隆可能会引入潜在bug需要被重点关注。该方法将为克隆代码质量评估和管理提供参考和支持。     

面向流数据分类的在线学习综述

流数据分类旨在从连续不断到达的流式数据中增量学习一个从输入变量到类标变量的映射函数,以便对随时到达的测试数据进行准确分类.在线学习范式作为一种增量式的机器学习技术,是流数据分类的有效工具.主要从在线学习的角度对流数据分类算法的研究现状进行综述.具体地,首先介绍在线学习的基本框架和性能评估方法,然后着重介绍在线学习算法在一般流数据上的工作现状,在高维流数据上解决“维度诅咒”问题的工作现状,以及在演化流数据上处理“概念漂移”问题的工作现状,最后讨论高维和演化流数据分类未来仍然存在的挑战和亟待研究的方向.     

Analyzing the evolutionary history of the logical design of object-oriented software

Today, most object-oriented software systems are developed using an evolutionary process model. Therefore, understanding the phases that the system's logical design has gone through and the style of their evolution can provide valuable insights in support of consistently maintaining and evolving the system, without compromising the integrity and stability of its architecture. In this paper, we present a method for analyzing the evolution of object-oriented software systems from the point of view of their logical design. This method relies on UMLDiff, a UML-structure differencing algorithm, which, given a sequence of UML class models corresponding to the logical design of a sequence of system code releases, produces a sequence of "change records" that describe the design-level changes between subsequent system releases. This change-records sequence is subsequently analyzed from the perspective of each individual system class, to produce the class-evolution profile, i.e., a class-specific change-records' sequence. Three types of longitudinal analyses - phasic, gamma, and optimal matching analysis - are applied to the class-evolution profiles to recover a high-level abstraction of distinct evolutionary phases and their corresponding styles and to identify class clusters with similar evolution trajectories. The recovered knowledge facilitates the overall understanding of system evolution and the planning of future maintenance activities. We report on one real-world case study evaluating our approach.     

基于模糊聚类分析的大型信息系统网络环境逻辑设计

本文提出了大型管理信息系统网络环境逻辑设计的方法和过程。通过引用信息系统需求分析的有关数据对数据和应用进行模糊聚类分析,研究数据和应用之间的内在关系,划分出各个子系统,计算出各子系统之间的数据流量,依此为依据,进行信息系统网络逻辑设计。     

Logical structure analysis: From HTML to XML

This paper presents an efficient method for extracting a logical structure from a Web document. The proposed method consists of three phases: visual grouping, element identification, and logical grouping. To produce a logical structure more accurately, the proposed method defines a document model that is able to describe logical structure information of a specific document class. Since the proposed method is based on a visual structure from the visual grouping phase as well as a document model that describes logical structure information of a document type, it supports sophisticated structure analysis. Experimental results with HTML documents from the Web show that the method has performed logical structure analysis successfully, compared with previous work. Particularly, the method generates XML documents as the result of structure analysis, so that it enhances the reusability of documents.     

Using requirement-functional-logical-physical models to support early assembly process planning for complex aircraft systems integration

The assembly line process planning connects product design and manufacturing through translating design information to assembly integration sequence. The assembly integration sequence defines the aircraft system components installation and test precedence of an assembly process. This activity is part of the complex systems integration and verification process from a systems engineering view. In this paper, the complexity of modern aircraft is defined by classifying aircraft system interactions in terms of energy flow, information data, control signals and physical connections. At the early conceptual design phase of assembly line planning, the priority task is to understand these product complexities, and generate the installation and test sequence that satisfies the designed system function and meet design requirements. This research proposes a novel method for initial assembly process planning that accounts for both physical and functional integrations. The method defines aircraft system interactions by using systems engineering concepts based on traceable RFLP (Requirement, Functional, Logical and Physical) models and generate the assembly integration sequence through a structured approach. The proposed method is implemented in an industrial software environment, and tested in a case study. The result shows the feasibility and potential benefits of the proposed method.     

Characteristics of multiple-component defects and architectural hotspots: a large system case study

The architecture of a large software system is widely considered important for such reasons as: providing a common goal to the stakeholders in realising the envisaged system; helping to organise the various development teams; and capturing foundational design decisions early in the development. Studies have shown that defects originating in system architectures can consume twice as much correction effort as that for other defects. Clearly, then, scientific studies on architectural defects are important for their improved treatment and prevention. Previous research has focused on the extent of architectural defects in software systems. For this paper, we were motivated to ask the following two complementary questions in a case study: (i) How do multiple-component defects (MCDs)—which are of architectural importance—differ from other types of defects in terms of (a) complexity and (b) persistence across development phases and releases? and (ii) How do highly MCD-concentrated components (the so called, architectural hotspots) differ from other types of components in terms of their (a) interrelationships and (b) persistence across development phases and releases? Results indicate that MCDs are complex to fix and are persistent across phases and releases. In comparison to a non-MCD, a MCD requires over 20 times more changes to fix it and is 6 to 8 times more likely to cross a phase or a release. These findings have implications for defect detection and correction. Results also show that 20% of the subject system’s components contain over 80% of the MCDs and that these components are 2–3 times more likely to persist across multiple system releases than other components in the system. Such MCD-concentrated components constitute architectural “hotspots” which management can focus upon for preventive maintenance and architectural quality improvement. The findings described are from an empirical study of a large legacy software system of size over 20 million lines of code and age over 17 years.     

Decision support system for classifying archaeological pottery profiles based on Mathematical Morphology

We present a decision support system to help archaeologists in classifying wheel-made pottery pieces by its profile. A novel shape characterization method, using Mathematical Morphology, is introduced for this purpose. Each profile is represented as a vector, obtained by sampling the so called morphological curves (erosion, dilation, opening and closing), and Euclidean Distance is used as a similarity measure. We show results of our method applied to a profile database of Iberian Pottery from the upper valley of Guadalquivir River (Spain).     

An Integrated Approach to Designing and Evaluating Collaborative Applications and Infrastructures

Collaborative systems include both general infrastructures and specific applications for supporting collaboration. Because of the relative newness and complexity of these systems, it has been unclear what approach should be used to design and evaluate them. Based on the lessons learned from our work and that of others on collaborative systems, we have derived an integrated approach to researching collaborative applications and infrastructures. The approach can be described as a sequence of steps: We decompose the functionality of collaboration systems into smaller functions that can be researched more-or-less independently. For each of these functions, we adopt general (system-independent) principles regarding the design and implementation of the function, identify collaboration scenarios at multiple levels of abstraction, identify requirements based on the scenarios, adopt an interaction model to meet the requirements, realize the interaction model as a concrete user interface, develop a logical architecture of the system, identify a physical architecture for placing the logical components in a distributed system, develop infrastructure abstractions, use the abstractions to implement applications, and perform lab studies, field experiments, and simulations to evaluate the infrastructure and applications. As in other models with multiple phases, feedback from subsequent phases is used to modify the results from the previous phases. In this paper, we describe, illustrate and motivate this research plan.     

基于逻辑等效模型的快速功能仿真验证

随着集成电路设计技术的发展,集成电路的规模越来越大,这使得在设计的各个阶段设计验证越来越重要,验证耗时的缩短也成为了SOC设计的关键。介绍了基于逻辑等效模型的快速功能仿真验证的方法和技巧,首先研究了验证的策略和方法,然后阐述了采用NC-Verilog进行快速功能仿真验证所使用的逻辑等效模型,最后给出了该方案的仿真结果和结论,证明该技术不仅能达到功能仿真验证的目的,而且有效地缩短了仿真周期,显著地提高了仿真效率。     

一种基于查表法的PLC交通信号控制系统新型编程方法

交通信号控制是典型的时间顺序控制,其传统基于继电器逻辑的PLC控制程序的显著缺点是逻辑关系较为复杂设计使在复杂情形时的交通控制信号程序不易设计.以罗克韦尔Micrologix 1500 PLC为例研究并设计了一种新型编程方法以解决这一问题.这个方法的核心是构建状态控制字表并通过查询该表实现交通信号的顺序控制.     

基于智能规划的界面自动生成方法研究

将智能规划方法引入到软件工程中的界面设计与开发领域,提出了一种基于智能规划的界面自动生成方法。应用该方法进行界面设计,可以较好地实现界面设计与代码实现的分离,降低程序的耦合度,并且可以明确界面间的逻辑关系,使开发者可以不用通过手动编程来实现界面先后调用的逻辑顺序。实践证明,该方法可以大大降低界面开发者的工作强度,缩短软件开发周期,节约开发成本。