Using a software reliability model to design a telecommunicationssoftware architecture

The author proposes a software reliability model for a large real-time telecommunications software architecture. Some simple examples of the critical components of the software architecture and their dependencies are described. The component dependencies permit the propagation of faults from the component in which the fault originates to the other components. This propagation can cause failures in the chain (or in the tree) of components. Detection and failures depends on the tests executed or on the number and type of customer requests. An error can occur in any component. This error can be caused by a fault that propagated from another component or it can be a fault that originates in that component. The error can be traced through the component-dependency chain (or tree) to repair all the faults that are associated with that error. The software reliability model guides the design of the software architecture     

A scenario-based reliability analysis approach for component-based software

This paper introduces a reliability model, and a reliability analysis technique for component-based software. The technique is named Scenario-Based Reliability Analysis (SBRA). Using scenarios of component interactions, we construct a probabilistic model named Component-Dependency Graph (CDG). Based on CDG, a reliability analysis algorithm is developed to analyze the reliability of the system as a function of reliabilities of its architectural constituents. An extension of the proposed model and algorithm is also developed for distributed software systems. The proposed approach has the following benefits: 1) It is used to analyze the impact of variations and uncertainties in the reliability of individual components, subsystems, and links between components on the overall reliability estimate of the software system. This is particularly useful when the system is built partially or fully from existing off-the-shelf components; 2) It is suitable for analyzing the reliability of distributed software systems because it incorporates link and delivery channel reliabilities; 3) The technique is used to identify critical components, interfaces, and subsystems; and to investigate the sensitivity of the application reliability to these elements; 4) The approach is applicable early in the development lifecycle, at the architecture level. Early detection of critical architecture elements, those that affect the overall reliability of the system the most, is useful in delegating resources in later development phases.     

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 in-fluencing system deployment. By translating the multi-dimension factors into degree matrix of com-ponent 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.     

Improving reliability through architecture partitioning intelecommunication networks

The paper presents a new switching architecture to improve telecommunications reliability. The architecture is partitioned depending on the type of network used, reliability requirements, and expected traffic in the network. The partition size depends on the network reliability, bandwidth, and traffic. A reliability model for a telecommunication architecture is used to partition the network and to improve end-to-end reliability. The model defines critical components in the networking architecture and their connections. The component connections permit the propagation of faults from the component in which the fault originates to the other components. This propagation can cause failures in the chain (or in the tree) of components. The partitioned architecture limits the propagation of faults, simplifies fault detection, and preserves reliability of the remaining partitions. Examples of different networks are used to show the applications of the model     

基于构件的分层体系结构模型的研究与应用

结合分层体系结构具有易于理解、易于进行人员分工的特点和构件实现了在程序级的软件复用这一优点，提出了基于构件的分层体系结构模型，并使用该模型实现了云南省教育厅网络工作平台的建设。验证了利用该模型所开发的系统具有很高的可用性、可靠性以及可维护性。     

航天测控站数据传输处理系统构件化设计

针对航天测控领域软件复用程度不高、软件开发效率低的现状,设计了基于构件技术的体系及架构。通过分析航天测控站数据传输处理系统领域模型,抽象出其各功能构件,结合软件总线体系结构,设计了基于内存映射的通信机制、连接构件及各功能构件,实现了航天测控站数据传输处理软件系统的构件化实例。这种方法实现了二进制方式的复用,在一定程度上提高了软件的质量,降低了开发维护成本,提高了可靠性。     

System reliability design with deteriorative components

In constrained optimum system reliability problems, the reliability of each component is usually assumed to be fixed, and the optimal number of redundancies at each stage is determined. However, in real world the component reliability decreases as component deteriorates; i.e. the component reliability is dependent on its age. This paper presents a system reliability optimization problem with deteriorative components. We formulate this problem as a parametric nonlinear integer programming problem where the objective function has a time parameter t. A solution method is proposed for solving it. We believe that this model can provide very useful information for decision makers and reliability designers.     

Analytical Models for Architecture-Based Software Reliability Prediction: A Unification Framework

Traditional approaches to software reliability modeling are black box-based; that is, the software system is considered as a whole, and only its interactions with the outside world are modeled without looking into its internal structure. The black box approach is adequate to characterize the reliability of monolithic, custom, built-to-specification software applications. However, with the widespread use of object oriented systems design & development, the use of component-based software development is on the rise. Software systems are developed in a heterogeneous (multiple teams in different environments) fashion, and hence it may be inappropriate to model the overall failure process of such systems using one of the several software reliability growth models (black box approach). Predicting the reliability of a software system based on its architecture, and the failure behavior of its components, is thus essential. Most of the research efforts in predicting the reliability of a software system based on its architecture have been focused on developing analytical or state-based models. However, the development of state-based models has been mostly ad hoc with little or no effort devoted towards establishing a unifying framework which compares & contrasts these models. Also, to the best of our knowledge, no attempt has been made to offer an insight into how these models might be applied to real software applications. This paper proposes a unifying framework for state-based models for architecture-based software reliability prediction. The state-based models we consider are the ones in which application architecture is represented either as a discrete time Markov chain (DTMC), or a continuous time Markov chain (CTMC). We illustrate the DTMC-based, and CTMC-based models using examples. A detailed discussion of how the parameters of each model may be estimated, and the life cycle phases when the model may be applied is also provided     

ActiveX，OLE和COM

基于面向对象技术的组件软件已成为软件技术发展的趋势。COM是一个组件软件模型 ,而OLE是一个基于COM的面向对象的体系结构 ,ActiveX是OLE的网络扩展型。就此 ,对三个组件软件ActiveX、OLE、COM作了较详细的介绍 ,分析了它们的特点、功能及体系结构。     

Determining Component Reliability and Redundancy for Optimum System Reliability

The usual constrained reliability optimization problem is extended to include determining the optimal level of component reliability and the number of redundancies in each stage. With cost, weight, and volume constraints, the problem is one in which the component reliability is a variable, and the optimal trade-off between adding components and improving individual component reliability is determined. This is a mixed integer nonlinear programming problem in which the system reliability is to be maximized as a function of component reliability level and the number of components used at each stage. The model is illustrated with three general non linear constraints imposed on the system. The Hooke and Jeeves pattern search technique in combination with the heuristic approach by Aggarwal et al, is used to solve the problem. The Hooke and Jeeves pattern search technique is a sequential search routine for maximizing the system reliability, RS (R, X). The argument in the Hooke and Jeeves pattern search is the component reliability, R, which is varied according to exploratory moves and pattern moves until the maximum of RS (R, X) is obtained. The heuristic approach is applied to each value of the component reliability, R, to obtain the optimal number of redundancies, X, which maximizes RS (R, X) for the stated R.     

基于组件技术的雷达组网系统软件设计

随着雷达组网系统的推广,必将对其适用性和扩展性提出越来越高的要求。文中分析了雷达组网系统的特点,提出了一种基于组件的雷达组网系统软件体系结构。以软件体系结构为指导,利用组件技术将复杂的雷达组网系统分解为具有特定功能的组件的集合,通过复用、集成具有各种功能的组件,可快速构建出面向各种军事应用的雷达组网系统软件。     

基于COTS构件组装的系统开发

基于构件的软件开发强调以集成为中心进行系统构造。文章介绍了构件及接口操作．定义了基于构件开发的相关概念，给出了构件配置算法，最后用一个实例说明了基于COTS构件的系统开发过程。     

J2EE构件化软件支撑平台研究与应用开发

为了提高软件复用程度,适应需求变化,提高业务应用系统开发效率和可维护性,研究了构件化、平台化的软件开发方法。基于Java2企业版（J2EE）的软件支撑平台,应用结构化、层次化和面向对象的方法,重点研究了软件支撑平台组成结构、软件构件定义、属性、表现和模型、构件分类与管理技术。同时,结合J2EE构件化软件支撑平台及其构件,研究了基于构件的业务应用软件的开发方法和过程模型。给出了基于J2EE的软件支撑平台的业务应用具体开发步骤,在多个实际项目中得到了应用。应用结果表明,提高了业务系统开发效率20％左右,软件复用显著提高,适应需求变化,可维护性增强。     

基于大功率电子器件的冷控系统设计

随着电子元器件的集成化程度越来越高,散热问题已经成为制约电子技术发展的主要因素之一.有效解决电子元器件的散热问题已经成为当前研究的热点问题.传统的风冷系统已经很难满足其散热要求.为此,以电子设备的水冷系统为研究对象,以ATmega 1280微处理器作为基础,设计了一款低成本、高效率的大功率电子器件的水冷控制系统,对系统各关键硬件模块做了详细的介绍,并采用模块化的方法给出了系统的软件架构.综合实验结果表明该系统操作方便、可靠性好、电磁兼容性强,具有较高的实用价值.     

基于异构信号处理平台的解调器组件化设计与实现

随着通信体制的日益发展,对应的解调算法也呈现多样化的形态。结合软件无线电技术的应用,研究高效、快捷的解调器开发方式显得越来越重要。文中利用软件无线电的思想和组件化方法,研究基于组件的数字解调器软件重构技术设计了解调器软件重构模型来解决重构的难题,并建立了解调器开发组件库。基于研制的组件库及解调器软件重构模型,以16QAM连续信号解调为目标,设计并基于新组件进行集成化开发,形成新的功能。通过测试,从误比特率对比验证重构的正确性及源代码复用率分析的角度证明,新方法的开发效率提高了71.63%。     

机载SDR系统SCA核心框架优化技术

针对软件通信架构(Software Communication Architecture,SCA)核心框架在机载领域臃肿和低效等问题,提出了一种面向机载软件无线电(Software Defined Radio,SDR)系统的SCA核心框架优化方案.首先,为使架构轻量高效,提出功能单元裁剪方法;其次,针对时间优化问题,分析了SCA的局限性,提出可灵活配置的加载流程优化技术,在兼容SCA规范的基础上可根据实际系统特点实施灵活的组件加载,充分发挥系统的并行加载潜力来缩短加载时间.实验结果表明,所提的优化技术能够有效提升SDR系统可用性,对面向机载SDR系统的SCA架构优化设计和应用具有较强的指导意义.     

面向云计算的软件架构研究

云计算的出现给IT领域带来了一场新的变革,今年是云计算发展非常重要的一年。随着全球对云计算研究的热潮,国际国内各大IT公司相继推出自己的云计算产品,这些云计算产品无一例外都是通过网络向用户提供服务的,这样对数据安全、可靠性和云计算服务自身的健壮性存在着挑战。随着云计算广泛的应用,传统的软件架构也将受到挑战,特别是在3层软件架构中的数据服务层将发生变化。     

SCA电台内部消息安全管理机制的设计与验证

SCA电台一般基于CORBA组件模型来设计业务、控制、信号处理、硬件抽象以及人机相关的各种组件,其分布式处理架构使得电台内部的业务数据难以集中管控,导致业务极不安全[S1],为解决该问题进行了深入的探索,研究了SCA软件架构及其安全架构,提出了电台内部业务消息的SCA组件化处理流程,给出了消息内容的安全集中管理机制以及消息存放位置单独传送的设计方法,并在SCA电台中对组件设计和安全集中管理机制进行了实现与测试验证。     

Redundancy Allocation for Series-Parallel Systems Using Integer Linear Programming

We consider the problem of maximizing the reliability of a series-parallel system given cost and weight constraints on the system. The number of components in each subsystem, and the choice of components are the decision variables. In this paper, we propose an integer linear programming approach that gives an approximate feasible solution, close to the optimal solution, together with an upper bound on the optimal reliability. We show that integer linear programming is a useful approach for solving this reliability problem. The mathematical programming model is relatively simple. Its implementation is immediate by using a mathematical programming language, and integer linear programming software. And the computational experiments show that the performance of this approach is excellent based on a comparison with previous results.