An illustration of verification and validation in the modelling phase of KBS development

Reliability has become a key factor in KBS development. For this reason, it has been suggested that verification and validation (V&V) should become an integrated part of activities throughout the whole KBS development cycle. In this paper, it will be illustrated how the PROLOGA workbench integrates V&V aspects into its modelling environment, such that these techniques can be of assistance in the process of knowledge acquisition and representation. To this end, verification has to be performed incrementally and can no longer be delayed until after the system has been completed. It will be shown how this objective can be realised through an approach that uses the decision table formalism as a modelling instrument.     

X射线机不是计量器具

计量学的基本理论指出，X射线机不具有计量器具的属性。国家的计量法规并未将X射线机定为计量器具。目前存在的JJG 40—2001《X射线探伤机》检定规程，将X射线探伤机与X射线检测技术相互混淆，将X射线探伤机的某些技术性能，说成所谓的X射线探伤机的“计量性能”，不仅违反计量学基本理论，而且也不符合射线检测技术实际。从计量学理论和射线检验实际经验只能得到X射线机不是计量器具的结论。     

Modeling and verifying probabilistic Multi-Agent Systems using knowledge and social commitments

Multi-Agent Systems (MASs) have long been modeled through knowledge and social commitments independently. In this paper, we present a new method that merges the two concepts to model and verify MASs in the presence of uncertainty. To express knowledge and social commitments simultaneously in uncertain settings, we define a new multi-modal logic called Probabilistic Computation Tree Logic of Knowledge and Commitments (PCTL^kc in short) which combines two existing probabilistic logics namely, probabilistic logic of knowledge PCTLK and probabilistic logic of commitments PCTLC. To model stochastic MASs, we present a new version of interpreted systems that captures the probabilistic behavior and accounts for the communication between interacting components. Then, we introduce a new probabilistic model checking procedure to check the compliance of target systems against some desirable properties written in PCTL^kc and report the obtained verification results. Our proposed model checking technique is reduction-based and consists in transforming the problem of model checking PCTL^kc into the problem of model checking a well established logic, namely PCTL. So doing provides us with the privilege of re-using the PRISM model checker to implement the proposed model checking approach. Finally, we demonstrate the effectiveness of our approach by presenting a real case study. This framework can be considered as a step forward towards closing the gap of capturing interactions between knowledge and social commitments in stochastic agent-based systems.     

基于实时UML顺序图的物联网交互模型

物联网是一个集计算、通信和控制于一体的智能系统,它通过监控和收集物理进程信息并将这些信息进行计算和分析,最终生成正确的控制指令用以执行,从而使物理环境变得更加安全和可靠。在物联网中,各物体通过网络连接或者本地连接的方式进行交互,这些交互具有时间性和地域性。物联网的建模和验证是物联网研究中一个重要的领域。文中提出一种基于实时UML顺序图的物联网交互模型,该模型将物联网中所有参与交互的物体建模为交互对象,并且通过实时UML顺序图对交互对象间的交互进行建模。使用时间自动机对交互对象的内部状态变化进行建模,以形成对交互模型的补充。最后根据转换规则将交互模型转换为时间自动机的形式以便于验证。通过一个实例,显示了如何具体应用物联网交互模型。进一步提出了物联网系统应该满足的一些性质,并使用UPPAAL模型检测工具对物联网交互模型进行分析和验证。     

Web交互模型的形式化验证研究

Web交互模型的形式化验证是对Web事件属性进行校验的十分可信的方法。通过一系列的系统模型建立、系统行为分析以及对于模型中关心属性的相关验证,能够让交互模型在设计阶段就能使形式化模型暴露出其所存在的缺陷,而不至于让缺陷保留到编码阶段或者更后面才能被真正地暴露出来,这样使系统模型的生存能力更加强大,同时避免了因后期缺陷暴露而出现的大代价修复。通过对Web系统的交互应用服务的过程模型化的体系进行研究,通过模型本身具有的属性进行相关正确性的校验,主要通过使用数学推理实现系统逻辑上的服务交互进程,从而进行过程的推演,并对系统服务的正确性进行过程的形式化验证,从而使系统服务模块的属性正确性可以通过逻辑上的演进来发现服务问题的存在,而不再是系统通过编码实现后才发现。对Web交互模型的形式化验证是基于IMWSC模型语义形成的IMWSC模型的验证机制。     

椭圆曲线上的链式验证签名

基于椭圆曲线密码算法,提出了一种新的链式验证签名方案,只有经过链式验证授权组中的成员P1、P2、...、Pn-1的一一授权之后,签名验证者Pn才能验证签名的有效性。分析了所给签名方案的安全性和效率。除了具有链式验证签名的一般特性外,还可以方便地增加或删除链式验证授权者,并在链式验证授权者或签名验证者泄漏子秘密时,可以及时地进行维护。     

基于Petri-Net的流程验证新方法

为解决业务流程管理应用系统中模型可验证性支持不足的问题,文章立足于业务流程建模和验证方法研究领域现状,以理论研究为基础提出一种面向应用系统的流程验证新方法。该方法利用PetriNet网络分析原理,聚焦于工作流网络模型,在关联矩阵、回归态、变迁序列等网络特征量的基础上推导出工作流网流程验证思路,形成了以PetriNet网络不变量求解为根本的验证算法。文中设计了实验对算法进行了理论分析验证和应用仿真验证,由此证明了文中算法的有效性。此外,为了体现算法的应用效能,对算法进行了效率分析实验,实验表明算法在验证效率上要明显优于覆盖图和因果足迹法。最后,依据文章的研究结果开发了验证算法的实用工具程序包,并对其应用效果进行了展示。综合而言,本文设计的流程验证方法合理高效,适合在实际系统中进行应用。     

Modelling of a dual circuit induced draft cooling water system for control and optimisation purposes

The successful operation of any petrochemical plant is dependent on the use of several utilities which may include electricity, steam, compressed air, cooling media, refrigeration media, nitrogen, condensate and fuel gas. These utilities form a significant portion of the fixed cost associated with running a plant. Utility optimisation has not received much attention until recently, driven by rising energy costs, stricter environmental policies, more competitive markets, and the threat of climate change. The generation, preparation, and transportation of utilities require energy and therefore should be optimised to reduce losses and improve operating efficiency. One example of such a utility is a cooling water system. This paper describes the modelling of a dual circuit induced draft cooling water system for control and optimisation purposes. The derived model is verified with plant data indicating promising results. The model is represented in a steady-state algebraic form as well as a dynamic state-space form. This provides a convenient basis for simulation studies and controller/optimiser design.     

Automating correctness verification of artifact-centric business process models

ContextThe artifact-centric methodology has emerged as a new paradigm to support business process management over the last few years. This way, business processes are described from the point of view of the artifacts that are manipulated during the process.ObjectiveOne of the research challenges in this area is the verification of the correctness of this kind of business process models where the model is formed of various artifacts that interact among them.MethodIn this paper, we propose a fully automated approach for verifying correctness of artifact-centric business process models, taking into account that the state (lifecycle) and the values of each artifact (numerical data described by pre and postconditions) influence in the values and the state of the others. The lifecycles of the artifacts and the numerical data managed are modeled by using the Constraint Programming paradigm, an Artificial Intelligence technique.ResultsTwo correctness notions for artifact-centric business process models are distinguished (reachability and weak termination), and novel verification algorithms are developed to check them. The algorithms are complete: neither false positives nor false negatives are generated. Moreover, the algorithms offer precise diagnosis of the detected errors, indicating the execution causing the error where the lifecycle gets stuck.ConclusionTo the best of our knowledge, this paper presents the first verification approach for artifact-centric business process models that integrates pre and postconditions, which define the behavior of the services, and numerical data verification when the model is formed of more than one artifact. The approach can detect errors not detectable with other approaches.