Achieving runtime adaptability through automated model evolution and variant selection

Dynamically adaptive systems propose adaptation by means of variants that are specified in the system model at design time and allow for a fixed set of different runtime configurations. However, in a dynamic environment, unanticipated changes may result in the inability of the system to meet its quality requirements. To allow the system to react to these changes, this article proposes a solution for automatically evolving the system model by integrating new variants and periodically validating the existing ones based on updated quality parameters. To illustrate this approach, the article presents a BPEL-based framework using a service composition model to represent the functional requirements of the system. The framework estimates quality of service (QoS) values based on information provided by a monitoring mechanism, ensuring that changes in QoS are reflected in the system model. The article shows how the evolved model can be used at runtime to increase the system's autonomic capabilities and delivered QoS.     

QoS-aware middleware for web services composition: a qualitative approach

Web services exhibit major industrial benefit by their ability to participate in composition processes. Web services composition allows for automated exchange of information among remote processes through the service interface. A well-established end-to-end QoS infrastructure among the involved processes precludes confusion among the developers, vendors and consumers. Most of the research work conducted in this domain has focused on functional QoS requirements such as service response time, delay, cost, etc. This paper elaborates the QoS of web services from the perspective of data freshness and accuracy. Towards this aim, the ‘Region Switching’ (RS) algorithm is introduced in this paper. Within the context of the multiple web services composition scenario, the RS-algorithm allows for accurate identification of the point of information change and the appropriate re-computation over the subset of the pre-established, global service execution plan. Thereafter, a mathematical model is presented to verify the need for re-computation based on certain estimated factors, computed thresholds, and the model design. Such a selective re-computation is worth considering since some services may take a significant amount of time to produce results where a slight change to the information set might not alter the outcome of the service. The proposed concept is implemented by utilising and extending the WS-Notification specification in order to elaborate a middleware that is capable of sensing and routing information change at the level of web services using the publish-subscribe mechanism. The contribution of this paper is threefold. First, it highlights the importance of qualifiable QoS aspect related to the issue of web services composition and monitoring. Second, it describes an algorithm capable of capturing and reflecting the state of web services involved in a composition process, thereby achieving higher QoS. Finally, the paper illustrates the use and extension of the WS-Notification concept in building such systems that would deliver up-to-date information to the user through selective re-computation of the web services composition plan.     

Applications integration in a hybrid cloud computing environment: modelling and platform

With the development of application services providers and cloud computing, more and more small- and medium-sized business enterprises use software services and even infrastructure services provided by professional information service companies to replace all or part of their information systems (ISs). These information service companies provide applications, such as data storage, computing processes, document sharing and even management information system services as public resources to support the business process management of their customers. However, no cloud computing service vendor can satisfy the full functional IS requirements of an enterprise. As a result, enterprises often have to simultaneously use systems distributed in different clouds and their intra enterprise ISs. Thus, this article presents a framework to integrate applications deployed in public clouds and intra ISs. A run-time platform is developed and a cross-computing environment process modelling technique is also developed to improve the feasibility of ISs under hybrid cloud computing environments.     

中国农民合作社变异的经济逻辑

本文把农民合作社看作是人力资本与非人力资本签订的一系列契约的联结,进而分析了中国农民合作社变异的经济逻辑。决定合作社成败的企业家人力资本在合作社的契约集合中很少体现,具有能动性的人力资本所有者就会积极寻求合作社的控制权以谋求人力资本的回报,并按照对自己有利的方式运营合作社。     

云计算及其在GIS中的发展

云计算是近几年来在计算机领域十分热门的一个词汇,随着技术的发展和市场的扩张,GIS开始与其他IT应用深度融合,并且逐渐进入IT应用的主流。在云计算的时代,GIS也面临着新的机会与变革。本文从云计算的概念和体系结构出发,论述了云计算的理论和关键技术。重点从GIS角度总结了目前云计算在国内外地理信息行业的应用情况。     

基于实时监控的网站反篡改系统设计

随着Internet和网络技术的发展,网站成为单位信息发布和宣传的重要平台。但随着网站建设的规模化和大众化,网站安全也成了日渐严峻的问题。本文提出了一种基于实时监控的Windows平台下网站反篡改系统的设计方案,用以提升网站安全防护能力。     

基于E-learning的《建筑材料》课程混合式教学模式新构建

随着E-learning在高校中的教与学中的应用及研究不断发展,以E-learning为基础的高校混合式学习模式受到了广泛的关注。就其平台的发展而论,目前许多专用的网络教学平台会出现不同程度的弊端,文章以腾讯QQ,土豆、优酷等视频网站,博客,知网等免费网络服务支持的教学行为特征为基础,结合《建筑材料》专业基础课实例,提出几种新的混合式学习模式,并对模式进行优缺点比较,以其对后续研究有所帮助。     

分布式存储系统中基于MPI的并行计算编程模型

海量的数据信息对WWW服务器的存储和检索系统提出了较高的要求,同时,互联网技术的发展为开发下一代适合高速发展的新的存储技术奠定了坚实的基础。为此,提出开发新一代基于消息传递编程接口的分布式网络数据存储系统。通过引入并行计算实现分布式存储系统的可靠性及可用性。     

基于移动Agent的企业级数据挖掘应用模型研究

移动Agent可以看作是人工智能与分布式计算技术相结合的产物,已经成为分布式计算研究的热点。该文通过对移动Agent关键技术进行分析,探索了将移动Agent技术与分布式数据挖掘相结合的可行性,讨论了采用移动Agent技术进行分布式数据挖掘时所遇到的问题及解决方案,提出了一个基于IBM Aglets 2.0.2移动Agent系统平台的企业级分布式数据挖掘应用模型,并给出了数据挖掘agent算法。     

Scheduling multimedia services in cloud computing environment

Currently, security is a critical factor for multimedia services running in the cloud computing environment. As an effective mechanism, trust can improve security level and mitigate attacks within cloud computing environments. Unfortunately, existing scheduling strategy for multimedia service in the cloud computing environment do not integrate trust mechanism when making scheduling decisions. In this paper, we propose a scheduling scheme for multimedia services in multi clouds. At first, a novel scheduling architecture is presented. Then, We build a trust model including both subjective trust and objective trust to evaluate the trust degree of multimedia service providers. By employing Bayesian theory, the subjective trust degree between multimedia service providers and users is obtained. According to the attributes of QoS, the objective trust degree of multimedia service providers is calculated. Finally, a scheduling algorithm integrating trust of entities is proposed by considering the deadline, cost and trust requirements of multimedia services. The scheduling algorithm heuristically hunts for reasonable resource allocations and satisfies the requirement of trust and meets deadlines for the multimedia services. Detailed simulated experiments demonstrate the effectiveness and feasibility of the proposed trust scheduling scheme.     

浅谈变压器在线监测技术的应用

变压器在线监测技术是变压器绝缘油气相色谱技术的补充和发展,能对产气速率做出连续、真实地反应,在早期就捕捉到故障现象,以掌握设备实际状况,并降低运行费用。文章分析了变压器在线监测技术的原理,并结合某厂的实际情况,介绍了该技术的应用。     

基于web services构建电子政务信息资源目录服务模型

为更好地实现分布式环境下的异构政务信息资源间透明性交互与共享,提出了一种基于政务信息资源目录服务的信息资源整合方案。针对目前政务资源整合现状,基于Web服务思想以及政务资源目录组织结构构,建政务资源目录服务模型,并结合信息资源注册及发现过程,对模型各部分组成、功能和构建方法进行了详述,最后对模型特点加以概括。     

Limited monitoring and the essentiality of money

Monetary theory emphasizes that imperfect monitoring is necessary for money to be essential, that is, for money to achieve socially desirable allocations. Little is known about how limited monitoring must be if money is to be essential, though. Understanding sufficient conditions for the essentiality of money is important since monitoring is a natural way in which credit is introduced in monetary models. In this paper, we show that money can fail to be essential even if monitoring is quite limited. This indicates that one must be careful when introducing monitoring in monetary models to allow for the coexistence of money and credit.     

基于云服务的供应链利益协调机制研究

云计算技术以其海量存储能力、计算能力和信息高度共享能力克服传统供应链在信息运作模式上的缺陷。文章建立了基于云服务的制造商主导的供应链Stackelberg博弈模型,并与传统供应链中各成员的利益进行比较。论证了基于云服务的供应链中各成员及供应链系统的利润相比传统供应链更优;一定条件下的售价更低、市场需求更大,并给出了供应链成员能够承受的云服务费的费用区间。验证了基于云服务的供应链的可行性。     

电子监管码推行一波三折

电子监管码是一种新产品质量追溯手段,利用电子监管码可供消费者进行真假与质量查询,可供政府进行打假,可供企业了解市场供求状况,尽管电子监管码有如此众多的好处,但在推行过程中却面临着许多问题,文中对此作了简要分析。     

崩塌、滑坡地质灾害监测现状

文章对目前国内外崩塌、滑坡地质灾害监测方法、仪器及监测目的、选择手段进行了综述,力求了解和掌握崩滑体的演变过程,及时捕捉崩滑灾害的特征信息,正确分析评价崩塌、滑坡,以尽量避免和减轻灾害损失。     

An intelligent service matching method for mechanical equipment condition monitoring using the fibre Bragg grating sensor network

Due to the advantages of being able to function under harsh environmental conditions and serving as a distributed condition information source in a networked monitoring system, the fibre Bragg grating (FBG) sensor network has attracted considerable attention for equipment online condition monitoring. To provide an overall conditional view of the mechanical equipment operation, a networked service-oriented condition monitoring framework based on FBG sensing is proposed, together with an intelligent matching method for supporting monitoring service management. In the novel framework, three classes of progressive service matching approaches, including service-chain knowledge database service matching, multi-objective constrained service matching and workflow-driven human-interactive service matching, are developed and integrated with an enhanced particle swarm optimisation (PSO) algorithm as well as a workflow-driven mechanism. Moreover, the manufacturing domain ontology, FBG sensor network structure and monitoring object are considered to facilitate the automatic matching of condition monitoring services to overcome the limitations of traditional service processing methods. The experimental results demonstrate that FBG monitoring services can be selected intelligently, and the developed condition monitoring system can be re-built rapidly as new equipment joins the framework. The effectiveness of the service matching method is also verified by implementing a prototype system together with its performance analysis.     

高速公路黄土路堤施工监控技术

在黄土地基上进行公路路基施工时,当路基填筑超过一定高度时,要合理控制填筑速度,确保路基沉降和侧位移满足要求,文章结合甘肃天定高速公路工程,介绍采用设置沉降板和侧位移桩的方法观测路基沉降和侧位移,通过对数据整理、分析,进行现场控制并对黄土路堤施工进行监控。     

高速公路边坡监测系统应用研究

根据已有的研究成果以及高速公路边坡工程的实际情况,文章初步阐明了建立与高速公路特点相适应的边坡监测系统的要求,提出了目前条件下建立公路边坡监测系统的一般程序。