基于QoS感知的动态服务组合

发布时间：2018-03-03 05:10

本文选题：QoS管理　切入点：服务组合　出处：《桂林电子科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：越来越多的组织和研究机构采用Web服务技术来实现数据共享和增值,使得部署在开放环境下的Web服务不断涌现。已有的关于Web服务组合的研究工作大多以Web服务的QoS(Quality of Service)信息真实可靠为前提,认为服务提供商提供的QoS信息能够反映服务的真实质量信息。实际上,Web服务的QoS信息由于受到网络负载以及地理位置的影响可能会不断的发生变化。为了度量这种变化对服务的QoS指标带来的影响,必须对服务的QoS信息进行实时监控与收集。此外,已有的关于服务组合的研究工作大多以执行代价最小或执行时间最短为衡量指标,而忽略了组合服务的全局QoS约束。表征服务交付能力的质量属性,往往也是用户所关心的,在Web服务组合系统中,这些属性不应该被忽视。随着组合效率得到日益关注,用户对组合算法的搜索性能也提出了更高的期冀,服务组合过程必须在合理的时间内给出响应。本文针对动态环境下基于QoS感知的服务组合系统的有效性及组合效率等问题,从QoS信息的监测、服务组合过程建模及分析等方面进行了一些研究,主要研究工作包括以下几个方面:(1)针对服务运行环境的复杂特点,并结合服务的QoS信息在运行过程中的动态多变的特性,给出了一个基于心智计算与合同网协议的多Agent协作模型与实现,用于QoS信息的实时监控,以支持Web服务运行过程中QoS信息的动态收集与更新;(2)提出了一种基于层次分析法的局部服务过滤策略,建立了“原子服务集合—QoS决策属性—目标服务”结构的层次分析模型,依据服务的QoS信息对局部服务进行过滤,减少全局服务优化选择需要搜索的范围;(3)为了保证组合服务能够满足全局QoS最优,提出了基于文化遗传算法的服务组合策略来处理具有全局约束的服务组合问题,将遗传算法作为文化算法的社会群体空间,并采用了多样性保持与相似染色体排斥策略以扩大种群的多样性和加快收敛速度,以保证服务组合系统的效率。最后通过实验对本文提出的基于心智计算和合同网协议的多Agent协同的效率进行了验证,同时验证并分析了局部服务选择对全局服务优化的积极作用,并对基于改进文化遗传算法在求解服务组合问题时的搜索效率和执行时间进行了实验和分析,实验结果证明所提方法具有良好的可执行性。
[Abstract]:More and more organizations and research institutions adopt Web services technology to achieve data sharing and value-added. Web services deployed in an open environment are constantly emerging. Most of the existing research work on Web services composition is based on the true and reliable QoS(Quality of Web services information. It is believed that the QoS information provided by the service provider can reflect the true quality information of the service. In fact, the QoS information of the web service may change continuously because of the influence of network load and geographical location. The impact of these changes on the QoS indicators of services, The QoS information of the service must be monitored and collected in real time. In addition, most of the research work on service composition is based on the minimum execution cost or the shortest execution time. The global QoS constraints of composite services are ignored. The quality attributes that characterize service delivery capabilities are often of concern to users. In Web service composition systems, these attributes should not be ignored. Users also have higher expectations for the search performance of the composition algorithm, and the service composition process must be responsive within a reasonable time. This paper aims at the effectiveness and composition efficiency of the service composition system based on QoS perception in dynamic environment. From the aspects of QoS information monitoring, service composition process modeling and analysis and so on, the main research work includes the following aspects: 1) aiming at the complex characteristics of service running environment, Combined with the dynamic and changeable characteristics of QoS information in service, a multi-#en1# cooperation model based on mental computing and contract net protocol is proposed, which can be used to monitor QoS information in real time. In order to support the dynamic collection and update of QoS information in the course of Web service operation, a local service filtering strategy based on AHP is proposed, and the hierarchical analysis model of "atomic service set-QoS decision attribute-target service" structure is established. Based on the QoS information of the service, the local service is filtered to reduce the scope of searching for global service optimization.) in order to ensure that the composite service can satisfy the global QoS optimization, A strategy of service composition based on cultural genetic algorithm is proposed to deal with the service composition problem with global constraints. The genetic algorithm is regarded as the social group space of the cultural algorithm. In order to expand the diversity and accelerate the convergence of the population, the strategies of diversity conservation and similar chromosome exclusion are adopted. In order to ensure the efficiency of the service composition system, the efficiency of multi-#en0# collaboration based on mental computing and contract net protocol is verified by experiments. At the same time, the positive effect of local service selection on global service optimization is verified and analyzed, and the search efficiency and execution time of the improved cultural genetic algorithm in solving service composition problems are tested and analyzed. The experimental results show that the proposed method is executable.
【学位授予单位】：桂林电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP393.09

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