Software architecture based software deployment reliability estimation considering architectural style

Software today often consists of a large number of components offering and requiring services. Such components should be deployed into embedded, pervasive environments, and several deployment architectures are typically possible. These deployment architectures can have significant impacts on system reliability. However, existing reliability estimation approaches are typically limited to certain classes or exclusively concentrate on software reliability, neglecting the influence of hardware resources, software deployment and architectural styles. The selection of an appropriate architectural style has a significant impact on system reliability of the target system. Therefore, we propose a novel software architecture （SA） based reliability estimation model incorporating software deployment and architectural style. On the basis of two architectural styles, we design influence factors and present a new approach to calculate system reliability. Experimental results show that influence factors provide an accurate and simple method of reflecting architectural styles and software deployment on system reliability. It is important for considering the influence of other architectural styles on system reliability in large scale deployment environment.

Estimation of Reliability and Cost Relationship for Architecture-based Software

In this paper, wc propose a new method to estimate the relationship between software reliability and software development cost taking into account the complexity for developing the software system and the size of software intended to develop during the implementation phase of the software development lifc cycle. On the basis of estimated relationship, a set of empirical data has been used to validate the correctness of the proposed model by comparing the result with the other existing models. The outcome of this work shows that the method proposed here is a relatively straightforward one in formulating the relationship between reliability and cost during implementation phase.

SOFTWARE RELIABILITY MODEL FOR COMPONENT INTERACTION MODE

With the rapid progress of component technology,the software development methodology of gathering a large number of components for designing complex software systems has matured.But,how to assess the application reliability accurately with the information of system architecture and the components reliabilities together has become a knotty problem.In this paper,the defects in formal description of software architecture and the limitations in existed model assumptions are both analyzed.Moreover,a new software reliability model called Component Interaction Mode(CIM) is proposed.With this model,the problem for existed component-based software reliability analysis models that cannot deal with the cases of component interaction with non-failure independent and non-random control transition is resolved.At last,the practice examples are presented to illustrate the effectiveness of this model.

An Approach to Modelling and Analysing Reliability of Breeze/ADL-based Software Architecture

Breeze/architecture description language（ADL）, is an eX tensible markup language（XML） based architecture description language which is used to model software systems at the architecture level. Though Breeze/ADL provides an appropriate basis for architecture modelling, it can neither analyse nor evaluate the architecture reliability. In this paper, we propose a Breeze/ADL based strategy which, by combining generalized stochastic Petri net（GSPN） and tools for reliability analysis, supports architecture reliability modelling and evaluation. This work expands the idea in three directions： Firstly, we give a Breeze/ADL reliability model in which we add error attributes to Breeze/ADL error model for capturing architecture error information, and at the same time perform the system error state transition through the Breeze/ADL production. Secondly, we present how to map a Breeze/ADL reliability model to a GSPN model, which in turn can be used for reliability analysis. The other task is to develop a Breeze/ADL reliability analysis modelling tool–EXGSPN（Breeze/ADL reliability analysis modelling tool）, and combine it with platform independent petri net editor 2（PIPE2） to carry out a reliability assessment.Abstract： Breeze/architecture description language （ADL）, is an eXtensible markup language （XML） based architecture description language which is used to model software systems at the architecture level. Though Breeze/ADL provides an appropriate basis for architecture modelling, it can neither analyse nor evaluate the architecture reliability. In this paper, we propose a Breeze/ADL based strategy which, by combining generalized stochastic Petri net （GSPN） and tools for reliability analysis, supports architecture reliability modelling and evaluation. This work expands the idea in three directions： Firstly, we give a Breeze/ADL reliability model in which we add error attributes to Breeze/ADL error model for capturing architecture error information, and at the same time perform the system error state transition through the Breeze/ADL production. Secondly, we present how to map a Breeze/ADL reliability model to a GSPN model, which in turn can be used for reliability analysis. The other task is to develop a Breeze/ADL reliability analysis modelling tool-EXGSPN （Breeze/ADL reliability analysis modelling tool）, and combine it with platform independent petri net editor 2 （PIPE2） to carry out a reliability assessment.

SA BASED SOFTWARE DEPLOYMENT RELIABILITY ESTIMATION CONSIDERING COMPONENT DEPENDENCE

Reliability is one of the most critical properties of software system.System deployment architecture is the allocation of system software components on host nodes.Software Architecture(SA) based software deployment models help to analyze reliability of different deployments.Though many approaches for architecture-based reliability estimation exist,little work has incorporated the influence of system deployment and hardware resources into reliability estimation.There are many factors influencing system deployment.By translating the multi-dimension factors into degree matrix of component dependence,we provide the definition of component dependence and propose a method of calculating system reliability of deployments.Additionally,the parameters that influence the optimal deployment may change during system execution.The existing software deployment architecture may be ill-suited for the given environment,and the system needs to be redeployed to improve reliability.An approximate algorithm,A*_D,to increase system reliability is presented.When the number of components and host nodes is relative large,experimental results show that this algorithm can obtain better deployment than stochastic and greedy algorithms.

Process Mining Discovery Techniques for Software Architecture Lightweight Evaluation Framework

This research recognizes the limitation and challenges of adaptingand applying Process Mining as a powerful tool and technique in theHypothetical Software Architecture (SA) Evaluation Framework with thefeatures and factors of lightweightness. Process mining deals with the largescalecomplexity of security and performance analysis, which are the goalsof SA evaluation frameworks. As a result of these conjectures, all ProcessMining researches in the realm of SA are thoroughly reviewed, and ninechallenges for Process Mining Adaption are recognized. Process mining isembedded in the framework and to boost the quality of the SA model forfurther analysis, the framework nominates architectural discovery algorithmsFlower, Alpha, Integer Linear Programming (ILP), Heuristic, and Inductiveand compares them vs. twelve quality criteria. Finally, the framework’s testingon three case studies approves the feasibility of applying process mining toarchitectural evaluation. The extraction of the SA model is also done by thebest model discovery algorithm, which is selected by intensive benchmarkingin this research. This research presents case studies of SA in service-oriented,Pipe and Filter, and component-based styles, modeled and simulated byHierarchical Colored Petri Net techniques based on the cases’ documentation.Processminingwithin this framework dealswith the system’s log files obtainedfrom SA simulation. Applying process mining is challenging, especially for aSA evaluation framework, as it has not been done yet. The research recognizesthe problems of process mining adaption to a hypothetical lightweightSA evaluation framework and addresses these problems during the solutiondevelopment.

Research on Software Structure Analysis Technology and Reliability Evaluation Method of Warship Equipment

In view of the current reliability evaluation requirements of warship equipment based on component, this paper comprehensively considered the characteristics of components,and the component identification method, structural decomposition method,component architecture modeling method were studied for warship equipment software. Based on the characteristics of warship equipment component, this paper proposed a formal modeling language based on Petri nets to realize the modeling of component software architecture and laid a foundation for the reliability evaluation method research of warship equipment component.

Mapping AADL to Petri Net Tool-Sets Using PNML Framework

Architecture Analysis and Design Language (AADL) has been utilized to specify and verify nonfunctional properties of Real-Time Embedded Systems (RTES) used in critical application systems. Examples of such critical application systems include medical devices, nuclear power plants, aerospace, financial, etc. Using AADL, an engineer is enable to analyze the quality of a system. For example, a developer can perform performance analysis such as end-to-end flow analysis to guarantee that system components have the required resources to meet the timing requirements relevant to their communications. The critical issue related to developing and deploying safety critical systems is how to validate the expected level of quality (e.g., safety, performance, security) and functionalities (capabilities) at design level. Currently, the core AADL is extensively applied to analyze and verify quality of RTES embed in the safety critical applications. The notation lacks the formal semantics needed to reason about the logical properties (e.g., deadlock, livelock, etc.) and capabilities of safety critical systems. The objective of this research is to augment AADL with exiting formal semantics and supporting tools in a manner that these properties can be automatically verified. Toward this goal, we exploit Petri Net Markup Language (PNML), which is a standard acting as the intermediate language between different classes of Petri Nets. Using PNML, we interface AADL with different classes of Petri nets, which support different types of tools and reasoning. The justification for using PNML is that the framework provides a context in which interoperability and exchangeability among different models of a system specified by different types of Petri nets is possible. The contributions of our work include a set of mappings and mapping rules between AADL and PNML. To show the feasibility of our approach, a fragment of RT-Embedded system, namely, Cruise Control System has been used.

Evaluation Method of Software Reliability Based on SPN Model

As a significant measure of software security evaluation, software reliability evaluation is also the basis of software safe operation. Traditional software system security evaluation methods are qualitative evaluation based on the functional and structural measurements, and it often ignores quantitative research based on invalidity and fault. This paper propose a stochastic transition function as a measure parameters of the reliability of stochastic Petri nets （SPN） theory. By calculating the probability of stability of the system, failure and mean time to first failure, it establishes an evaluation and measurement method for software reliability. With example analysis, the method can conduct effective evaluation on the software reliability index quickly and accurately, and meanwhile provides a new method for the software security evaluation.

基于模糊神经Petri网的软件系统可靠性评估方法

针对软件系统可靠性建模难问题,提出了一种新的适用于软件系统可靠性估计的模糊神经Petri网(简称为FN-PN)。文章首先给出了模糊神经Petri网的定义及其引发规则,然后给出了一种学习算法。该FNPN结合了模糊Petri网和神经网络各自的优点,既可以表示和处理模糊产生式规则的知识库系统又具有学习能力,可通过对样本数据学习调整模型中的参数以获得系统内部的等效结构,从而计算出非样本数据的系统的可靠度。最后用实例分析验证了该方法的可行性。

基于Petri网的面向动态演化的软件体系结构建模

为了应对软件动态演化面临的挑战,应提高所建立的软件体系结构模型的动态演化性。以扩展的Petri网为形式化工具,对面向动态演化的软件体系结构进行建模。首先,将Petri网扩展成为构件网结构,并设计有效支持软件动态演化的构件模型和连接件模型;其次,建立软件体系结构的静态视图和动态视图,为软件动态演化的分析和实施奠定基础;最后,通过案例研究表明:该方法是有效的,并可显著提高所建立的软件体系结构模型的动态演化性。

基于Petri网的软件体系结构可靠性分析

近年来,软件体系结构已成为软件工程领域的研究热点以及大型软件系统与软件产品线开发中的关键技术之一。对软件体系结构的可靠性分析是进行软件开发的一个重要依据,为了提高软件系统的性能,一个可靠的体系结构是整个软件系统的基础。文章通过分析体系结构的特征和可靠性因素,提出了一种基于Petri网的体系结构可靠性分析方法,对软件体系结构的各因素的可靠性进行分析评估,从而推导出整个软件体系结构的可靠性,并对软件体系结构可靠性进行实例研究。

基于非马尔可夫随机Petri网的软件再生建模与分析

软件老化是影响软件系统可靠性的重要潜在因素,软件再生作为一种主动预防性的软件容错技术是解决软件老化问题的主要手段.以往的随机Petri网再生模型假定所有变迁的实施时间服从指数分布.针对变迁的实施时间服从确定性分布或一般性分布的情况,文中提出了一种用非马尔可夫随机Petri网建立软件再生模型的方法.该方法采用马尔可夫再生理论对模型进行分析,并给出模型的瞬态解和稳态解.仿真实验表明:选择合适的软件再生周期,可以有效地降低存在老化的软件系统的平均宕机成本,提高系统的可用性和可靠性.

基于时间扩展Petri网的实时嵌入式软件体系结构建模及可靠性评估

软件可靠性是软件质量评估最重要的指标之一,随着软件工程和组件重用技术的发展,近年来基于体系结构的软件可靠性评估已经成为工程研究的热点之一。为有效地提高软件可靠性,调研现有体系结构的可靠性评估模型,给出了现有体系结构模型的分类和模型代表,并分析了现有模型的不足。由于Petri具有良好的扩展性并且对异步和并行软件有良好的描述性,因此重点研究Petri网可靠性评估模型,通过划分时间变迁和瞬时变迁,并引入时间相关的可靠度,包括延时可靠度与时序可靠度,对Petri网进行了扩展,给出了时间扩展的Petri网进行体系结构建模方法。通过研究组件状态和系统可达状态的关系,创建可达状态转移矩阵,对系统进行可靠性评估。将所研究的方法应用于某航电嵌入式系统软件中,完成了体系结构建模及可靠性评估,并通过误差分析验证了该方法的有效性及准确性。

基于扩展Petri网的安全关键软件需求模型检验

Petri网是系统建模的形式化方法,为了解决其在软件需求建模和建立程序语义映射方面存在的不足,提出了一种扩展Petri网的方法来支持软件需求建模,区分了状态型和数值型库所,根据软件特点有针对性地扩展了变迁的可触发条件和迁移运算,同时建立了和模型检验程序语言的映射,将扩展Petri网作为检验的模型输入,利用时态逻辑描述运行性质,进行需求模型检验.定时器和航空发动机的防喘功能验证实例结果表明,扩展Petri网可以较好地支持软件系统需求建模和软件程序语义映射,通过模型检验和反例路径分析,可以达到修改和完善需求模型的目的,从而提高软件的质量和安全性.

基于体系结构的软件过程Petri网模型

传统的软件过程模型存在开发效率不高 ,可移植性差 ,重用粒度小等缺点 .Petri网由于自身的特点 ,可用于形式化描述软件过程 ,学术界已有部分研究 .但已经发表的研究多是基于高级 Petri的扩展 ,十分复杂和繁琐 ,难以应用到实际软件项目中 .综合利用软件过程理论、软件体系结构理论以及 Petri网理论 ,提出了基于体系结构的软件过程Petri网模型 (ABSPN) ,并证明了 ABSPN模型具有过程正确性、强连通性、活性和有界性 .实践证明 ,采用 ABSPN模型进行软件开发 ,可以使软件结构清晰 ,易于理解 ,可移植性强 。

基于随机Petri网的嵌入式软件能耗模型

传统的软件能耗测量方式是在软件设计完成后进行实际测量从而得到能耗值,不能在软件的设计初期形成一定的数据量为开发做出参考。为此,从体系结构层面对软件进行构件化处理,基于随机Petri网分别对构件、接口、连接件各模块进行建模与分析,构造出嵌入式软件能耗模型ESPN。给出寻找3种能耗路径的方法,根据能耗状态可达图对软件能耗进行预测并求得其确切值。通过实例化分析与设计验证了该模型的有效性。

一种软件可靠性评估模型及其Petri网描述

通过提出k-可靠模型,对现有软件可靠性评估方法所依据的模型进行重构,并根据Petri网及软件可靠性的相关理论,对构成软件系统的各个组件进行可靠性评估,从而实现对软件系统的可靠性评估,并介绍一种自底向上的可靠性计算过程。该方法能对软件系统的进行分解和综合计算,达到对整个软件系统可靠性评估的目的。

基于灰色随机Petri网的构件化软件可靠性早期评估方法

针对构件化软件系统本身的复杂性和早期可靠性评估存在的"贫信息、少数据"的问题,提出了一种灰色随机Petri网(GrSPN)模型。该模型在随机Petri网的变迁速率中引入灰数,首先结合系统GrSPN模型的可达树确定系统的状态标识集及其子集,然后将得到的GrSPN转化为与其同构的连续时间马尔可夫链(MC)。通过对MC的平稳状态分布对软件系统可靠性进行分析,得到用灰数表示的稳态概率,然后根据白化权函数对结果进行白化,得到软件系统每个可达状态标识下的稳态概率,进而求得系统可靠度。最后,结合某构件化软件可靠性早期评估实例验证了该模型的有效性。

基于Petri网运行状态的组件化软件可靠性分析方法

通过分析软件系统的组件结构特征、运行状态和可靠性因素,提出了基于随机Petri网运行状态的可靠性分析方法。对构成软件系统的各组件的可靠性进行分析和评估,根据系统运行状态动态跟踪软件的可靠性,推导出整个软件系统的可靠性。与仅着眼于系统组件间的执行路径不同,该方法更关注于系统各个运行状态的可靠性。最后给出了一个实例研究。