Dynamic model for the system testing process

The approach for estimating and controlling the software testing effort presented in this paper is based on the theory of dynamical systems. The system testing process is modeled by a dynamical system to better understand its behaviour and to assist project and test managers in planning and tracking effort needs.The proposed model is based on worktime effort measurement and has been applied on three industrial software development projects data. In comparison to other models of the literature the worktime based system testing model describes the behaviour of the process more adequately. Consequently, decisions about the duration of system testing can be supported. Previous models from reliability modelling were selected for comparison. However, the emphasis here is placed on industrial experience on effort tracking and control.     

Architecting Fault Tolerance with Exception Handling: Verification and Validation

When building dependable systems by integrating untrusted software components that were not originally designed to interact with each other, it is likely the occurrence of architectural mismatches related to assumptions in their failure behaviour. These mismatches, if not prevented during system design, have to be tolerated during runtime. This paper presents an architectural abstraction based on exception handling for structuring fault-tolerant software systems. This abstraction comprises several components and connectors that promote an existing untrusted software element into an idealised fault-tolerant architectural element. Moreover, it is considered in the context of a rigorous software development approach based on formal methods for representing the structure and behaviour of the software architecture. The proposed approach relies on a formal specification and verification for analysing exception propagation, and verifying important dependability properties, such as deadlock freedom, and scenarios of architectural reconfiguration. The formal models are automatically generated using model transformation from UML diagrams: component diagram representing the system structure, and sequence diagrams representing the system behaviour. Finally, the formal models are also used for generating unit and integration test cases that are used for assessing the correctness of the source code. The feasibility of the proposed architectural approach was evaluated on an embedded critical case study. Patrick Brito is supported by Fapesp/Brazil under Grant No. 06/02116–2 and CAPES/Brazil under Grant No. 0722–07–3. Cecília Rubira is partially supported by CNPq/Brazil under Grant Nos. 301446/2006–7 and 484138/2006–5.     

Testing interruptions in reactive systems

Modelling and testing of reactive systems with interruptions are discussed. These systems are commonly found in portable devices, where interruptions to a running application can be demanded at any time, due to concurrent execution of processes sharing a single resource, such as screen, as well as arrival of calls from network distributed services. Since the possible number of combinations of allowed interruptions is large, proper test case selection activities need to be performed. But, in order to systematically investigate and select test cases, it is fundamental to explicitly model interruption behaviour in a compositional way, avoiding the need for explicit enumeration. This work presents a strategy for testing interruptions in reactive systems that covers modelling for testing of systems with interruptions, generation and selection of sound test cases. The strategy is supported by the LTS-BT tool. Moreover, a formal model of an environment devoted to execution of test cases with interruptions is presented. Finally, a case study illustrates its applicability in the mobile phone application domain.     

Merged processes: a new condensed representation of Petri net behaviour

Model checking based on Petri net unfoldings is an approach widely applied to cope with the state space explosion problem. In this paper, we propose a new condensed representation of a Petri net’s behaviour called merged processes, which copes well not only with concurrency, but also with other sources of state space explosion, viz sequences of choices and non-safeness. Moreover, this representation is sufficiently similar to the traditional unfoldings, so that a large body of results developed for the latter can be re-used. Experimental results indicate that the proposed representation of a Petri net’s behaviour alleviates the state space explosion problem to a significant degree and is suitable for model checking.V. Khomenko is a Royal Academy of Engineering/Epsrc Research Fellow supported by the RAEng/Epsrc grant EP/C53400X/1 (Davac).M. Koutny is supported by the EC IST grant 511599 (Rodin).W. Vogler is supported by the DFG-project STG-Dekomposition VO 615/7-1     

分布式通用测试结构的形式化研究

随着分布式系统的不断发展更新,ＣＴＭＦ（ＩＳＯ／ＩＥＣ９４６４）所给出的测试方法不能满足的需要。提出了用于分布式系统的一致性没试互操作测试和性能测试的通用测试结构 ,并建立了用测试结构和形式化模人出了各部件的操作语义,为设计开发具有灵活动态的通信结构的分布测试系统提供了理论基础和依据,分布式系统通用测试结构扩展,当前基于被测系统类型的测试方法,它可以对实际的分布式系统进行整体测试。     

Levels of atomic action in the Flagship parallel system

The Flagship system is a graph reduction machine having a distributed physical architecture. Although Flagship sits firmly in the declarative world, explicit state is supported to express the behaviour of the operating system. This state not only has to be isolated from the declarative aspects of the Flagship machine, but also has to be supported with respect to distribution. The mechanisms provided for maintaining consistency of state are discussed with respect to atomic actions at levels in the Flagship system. This approach is used to demonstrate how the software environment was supported by the basic execution mechanism of the machine. The nature, construction and creation of system software components are described and the structure of the system software is discussed with particular reference to optimising access to distributed resources.     

The lies we tell and what they say about us: Using behavioural characteristics to explain Facebook activity

Are there two definable groups of users of social networking sites based on the individual’s interaction style, that is whether the prime goal is to self-promote (broadcast) or maintain relationships (communicate)? Do such groups indulge in differing patterns of deceptive behaviour? Measures of personality, behaviour, and Facebook activity were completed by 113 undergraduate students all of which were active Facebook users. Regression analyses showed that while broadcasting behaviour was predicted by risk taking, an out-going personality and an absence of quality interaction; low mild social deviance predicted communication behaviour. Unexpectedly, cluster analysis identified three, not two, distinct groups of users: high broadcasters, high communicators and a high interaction group. Although each group mainly interacted with known others, their style of the interaction varied. Communicators’ interaction style supported group cohesion often through the use of ‘white lies’ or social oil; while the remaining two groups indulged in deceptive behaviour designed to self-promote or aggrandize the individual.     

Numerical analysis of sheathing boards influence on racking resistance of timber-frame walls

This paper provides a numerical analysis of sheathing boards influence on racking resistance of timber-frame walls coated with single sheathing boards fastened to a timber frame. Worldwide, the walls are usually broadly used as main bearing capacity vertical elements in prefabricated residential timber buildings. Designers or producers usually face the important dilemma of using the best sheathing board with regard to the height and location of a building. The presented research thus aims at comparing the results obtained through calculations made on test samples covered with either fibre-plaster or wood-based sheathing boards. Therefore, the presented conclusions, supported by the measured results, propose some important indications in behaviour of the timber-framed wall elements under a horizontal load covered with different sheathing boards and present some useful recommendations in designing of tall timber-framed buildings located on heavy windy or seismic area.     

Computing low Mach number flows by parallel adaptive multigrid

A method to simulate compressible flows at all speed on unstructured grids is presented. Special effort is set on low Mach number flows both in two and three dimensions. Weakly compressible flows can be treated by applying an asymptotic analysis to the equations. The behaviour of a multigrid method solving the linearized system is shown. Furthermore adaptive grid refinement and parallelization is used.This work was supported by the Deutsche Forschungsgemeinschaft, Schwertpunktprogramm ANuME.     

基于Sockets的计算机支持协同工作平台 测试技术研究

计算机支持协同工作是在计算机支持的环境中,一个群体协同工作完成一项共同的任务。它的基本内涵是计 算机支持通信、合作和协调。本文通过对典型的计算机支持协同工作平台系统工作流程的分析,提出录制、分析、增加测试脚 本的方法。     

Prototyping and analysing ubiquitous computing environments using multiple layers

If ubiquitous computing (ubicomp) is to enhance physical environments then early and accurate assessment of alternative solutions will be necessary to avoid costly deployment of systems that fail to meet requirements. This paper presents APEX, a prototyping framework that combines a 3D Application Server with a behaviour modeling tool. The contribution of this framework is that it allows exhaustive analysis of the behaviour models that drive the prototype while at the same time enabling immersive exploration of a virtual environment simulating the proposed system. The development of prototypes is supported through three layers: a simulation layer (using OpenSimulator); a modelling layer (using CPN Tools) and a physical layer (using external devices and real users). APEX allows movement between these layers to analyse different features, from user experience to user behaviour. The multi layer approach makes it possible to express user behaviour in the modelling layer, provides a way to reduce the number of real users needed by adding simulated avatars, and supports user testing of hybrids of virtual and real components as well as exhaustive analysis. This paper demonstrates the approach by means of an example, placing particular emphasis on the simulation of virtual environments, low cost prototyping and the formal analysis capabilities.     

轻量级接口自动化测试框架设计与实践

某后端服务产品接口多,接口功能复杂,针对该产品多版本迭代测试时需执行的测试用例数多达上万条,以手动测试方式难以满足短时间版本频繁迭代的测试需求。为了对该产品实现自动化测试,基于面向对象、Web页面开发等技术,借鉴JUnit的分层思路,设计并实现了一套较实用的轻量级接口自动化测试框架。框架支持自动生成内含各测试用例细节描述及对应结果等信息的测试结果文件,支持以Web页面形式对测试结果进行个性化展示与浏览。基于此框架的自动化测试能在短时间内高效、准确地完成多个版本、上万条测试用例的快速执行,有效地解决了该产品因短时间版本频繁迭代所带来的测试压力。     

A compositional dataflow semantics for Petri nets

We give a semantics for place/transition nets, which describes the input/out-put behaviour using fixed point techniques. The semantics is shown to be compositional w.r.t. the net operators parallel composition, feedback and output merging. We prove consistency with the step sequence semantics and thus give an equivalent operational semantics.This work was partially supported by the Deutsche Forschungsgemeinschaft, SFB 342     

Asymptotic deformation modes of benchmark problems suitable for evaluating shell elements

An analytical approach introduced recently concerning the definition of the limiting cases of the asymptotic behaviour of shell elements is critically reviewed. A simple analytical approach for defining the asymptotic behaviour of shell elements is proposed. This approach is employed to define and analyse the asymptotic deformation modes of selected benchmark problems suitable for the evaluation of the asymptotic behaviour of shell elements. A new limit test problem, the hyperbolic paraboloid shell problem, proposed as a strong test for the pure bending asymptotic behaviour of shell elements, is analysed in the context of the proposed approach. Explicit expressions for characteristic asymptotic displacements are derived for the shell benchmark problems considered. These expressions are proposed for testing the asymptotic behaviour of finite shell elements in membrane-dominated, bending-dominated and mixed membrane-bending mode shell problems.     

无线传感器网络中基于行为可信安全认证机制

从传感器行为的空间相关性和时间相关性入手,提出一种基于相似度的以局部检测为主的分布式传感器行为信任认证机制.该机制通过检验传感器本地采样值构成的时空相似度与传感器行为随机过程统计特征的符合程度实现行为信任认证.模拟仿真试验表明,该机制可以减少传感器之间的数据交换,当网络中10%的传感器存在不安全行为时,该模型可以检测到93%的不可信传感器.     

Test generation for radiotherapy accelerators

System specification with Lotos (Language Of Temporal Ordering Specification) is briefly introduced. To make test generation practicable, specifications are annotated with event constraints using PCL (Parameter Constraint Language) as a means of stating test purposes. Automated test generation can then use the principle of input-output conformance to check whether an implementation agrees with its specification. Test suites are generated by a transition tour that either visits every transition at least once (for infinite behaviour) or follows every path (for finite behaviour). The approach is applied to a case study in which tests are generated for radiotherapy accelerators used in cancer treatment. A typical specification and set of test purposes yields 256 test cases that can be executed manually or automatically. The goal is to determine situations in which an accelerator does not behave in conformity with its specification.     

State estimation in robotic manipulators: Some experimental results

A simple asymptotic observer is proposed for the estimation of the generalized veocities of a robotic manipulator. The singular perturbation theory is used in the stability analysis of the error dynamics. High-gains are used in the attenuation of the nonlinearities characterizing the dynamic behaviour of the robot. The accuracy of the proposed algorithm is illustrated in simulation runs and verified through some experimental tests.This work was supported by CNR funds, under contract No. 89.00531.67.     

Measurement based analysis of temporal behaviour as support for scheduling problems in parallel and distributed real-time systems

Static analysis, based on scheduling techniques, provides the most typical approach for validation of real-time systems. However, in the case of complex real-time systems such as parallel and distributed systems, many simplifications are made in order to make analysis tractable. This means that even if the system can be statically validated, the real behaviour of the system in execution may be different enough from its theoretical behaviour to make it invalid. In these cases, an analysis based on measurement of the system in execution constitutes an invaluable aid to the static analysis. This article describes a methodology for the analysis of the temporal behaviour of parallel and distributed real-time systems with end-to-end constraints. The analysis is based on the measurement of a prototype of the system in execution and is supported by a behavioural model. The main components of the model are the sequences of activities throughout the system tasks (transactions), which are carried out in response to input events, causing the corresponding output events. Thus, the temporal behaviour of the system is viewed as a set of real-time transactions competing for the available resources. This article also includes experimental results of applying the methodology to the analysis of a well-known case study.     

无线传感器网络中一种基于行为可信的访问控制机制

访问控制是无线传感器网络的一种重要应用,已有研究工作大多是通过相部传感器之间的密钥交换来实现。 从传感器行为的空间相关性和时间相关性入手,提出了一种基于相似度的以局部检测为主的分布式传感器行为可信 的访问控制机制。该机制通过检验传感器本地采样值构成的时空相似度与传感器行为随机过程统计特征的符合程度 来实现行为信任的访问控制。模拟仿真试验表明,该机制可以减少传感器之间的数据交换,当网络中10%的传感器 存在不安全行为时,该模型可以检测到}J%的不可信传感器。     

遥感影像数据库研究

该文首先对目前国内外遥感影像数据库方面的研究工作做了介绍,并对一些重要遥感影像数据库系统实施方案进行了具体实践和测试,在此基础上针对各方案的技术路线、支持的操作系统及数据库平台、影像数据库的管理方式、系统体系结构、影像数据压缩方案、电子地图支持能力和使用的软件平台等7个方面做出了具体测试和分析,并给出测试结果和最终结论。