基于状态的增量式类测试策略SITS

基于状态的测试是面向对象软件测试的一个重要方面。本文在FREE状态测试模型的基础上，提出了一种基于状态的增量式类测试策略。首先提出了一种全面测试基类的显式、隐式行为的测试策略；然后在进行面向对象软件测试时，对于子类的测试，加入增量式测试的思想，以简化测试实例的数量及测试执行时间；最后对SITS策略的测试实用性进进行了概括性总结。     

A generalized model for dynamic mixed-mode fracture via state-based peridynamics

A generalized model is developed to investigate dynamic crack propagation in isotropic solids under mixed-mode I/II conditions using state-based peridynamics. The critical stretch and the critical strain energy release rate (ERR) are related within the state-based peridynamic framework to construct a computational model capable of capturing fracture energy of the kinked cracks. A novel formulation is presented to predict crack growth trajectory and pattern by combining the traditional expression of ERR and the peridynamic states of the crack opening and sliding displacements. The proposed model is used to predict dynamic fracture behavior in polymethyl methacrylate (PMMA) and soda-lime glass using various test specimens, including cracked semi-circular bending (SCB), cracked rectangular plate, and single edge-notched tensile (SENT) specimens, and under different dynamic loading conditions. The developed model is examined against the numerical and experimental data available in the literature, and a very good agreement is observed.     

DTS: Dynamic TDMA scheduling for Networked Control Systems

Networked Control Systems (NCSs) are pervasively applied in modern industry. With increasing functionalities, modern NCSs tend to have dynamic workload by holding a variety of applications via a shared network. To handle workload variations and provide performance guarantees, dynamic network scheduling scheme is highly desired in NCSs. In this paper, we propose a network scheduling scheme, referred to as DTS, that can make on-the-fly decisions to schedule the applications in NCSs. DTS aims at NCSs that use time-triggered network as shared medium and Time division multiple access (TDMA) as network access method. DTS dynamically changes the network accessing sequence of the applications in a way to provide optimal system performance and maintain control stability in NCSs. DTS adopts a decentralized schedule mechanism where each application can make its local schedule decision, enhancing the scalability of NCSs. Simulation results demonstrate the effectiveness of the proposed scheme by improving the network bandwidth and providing better system performance in NCS comparing with the existing time-triggered scheduling schemes.     

基于状态的类测试研究

类是面向对象程序语言的基本组成单位,所以类测试是整个面向对象软件测试的关键所在;论文主要针对传统状态测试方法在发现错误机制上存在的不足,研究了一种利用OSD模型的基于状态的类测试方法,提出了利用OSD模型与系统分析设计的状态图模型进行比较的思想;通过比较两个状态图模型中的状态是否一致以及各个状态间的方法转移是否一致,来发现传统状态测试难以发现的错误;实践证明,该方法能够检测出传统的状态测试方法难以检测到的错误。     

基于故障预警系统的燃煤发电设备状态检修

基于故障预警系统的状态检修是随状态监测技术发展起来的至今最先进的检修方式。20世纪90年代中国开始推行发电设备状态检修,成效明显者寥寥。为切实推行发电设备状态检修方式,某发电集团从2008年开始引进、开发并推广应用了利用相似性原理建模技术的发电设备故障预警系统。介绍了该系统的机理,并用汽轮机、锅炉、电气和化学专业各1个预警案例阐述故障预警系统在燃煤发电设备状态检修中的有效应用情况,最后就如何将两者更好地结合提出了建议。     

混凝土板裂纹扩展的态型近场动力学模拟

构建考虑混凝土拉压异性和宏观断裂特征的混凝土类材料非局部态型近场动力学本构模型,并通过引入动态松弛、系统失衡判断和力边界等效等算法,构建适于分析混凝土类材料和结构变形破坏过程的态型近场动力学数值模拟体系.通过分组模拟和定量计算,分析算法的收敛性、计算精度和效率等问题;在此基础上开展含不同角度中心裂纹混凝土板的破坏模拟.     

A Hybrid Approach to Online and Offline Partial Evaluation

This article presents a hybrid method of partial evaluation (PE), which is exactly as precise as naive online PE and nearly as efficient as state-of-the-art offline PE, for a statically typed call-by-value functional language.PE is a program transformation that specializes a program with respect to a subset of its input by reducing the program and leaving a residual program. Online PE makes the reduction/residualization decision during specialization, while offline PE makes it before specialization by using a static analysis called binding-time analysis. Compared to offline PE, online PE is more precise in the sense that it finds more redexes, but less efficient in the sense that it takes more time.To solve this dilemma, we begin with a naive online partial evaluator, and make it efficient without sacrificing its precision. To this end, we (1) use state (instead of continuations) for let-insertion, (2) take a so-called cogen approach (instead of self-application), and (3) remove unnecessary let-insertion, unnecessary tags, and unnecessary values/expressions by using a type-based representation analysis, which subsumes various monovariant binding-time analyses.We implemented and compared our method and existing methods—both online and offline—in a subset of Standard ML. Experiments showed that (1) our method produces as fast residual programs as online PE and (2) it does so at least twice as fast as other methods (including a cogen approach to offline PE with a polyvariant binding-time analysis) that produce comparable residual programs.     

面向对象软件类测试研究新进展

软件测试是软件开发过程中不可缺少的一环,是保证软件质量和提高软件可靠性的关键.近年来,随着面向对象软件开发方法应用的更加广泛和研究的不断深入,面向对象软件测试已成为软件工程领域的一个重要研究课题.类是面向对象软件的基本构成单元,类测试是面向对象软件测试的关键.从基于状态、基于规范、基于UML、基于方法序列、基于数据流等6方面论述了类测试的目前研究成果,分析了研究现状,探讨了进一步工作的方向.