虚拟社区云及其服务副本放置策略的研究

发布时间：2018-05-03 23:42

本文选题：Web服务 + 虚拟社区云　；参考：《西北师范大学》2014年硕士论文

【摘要】：在生物信息等研究领域，为实现领域相关的软件和数据等资源的共享，通过互联网技术形成了大量的虚拟社区。从事特定领域研究的个人或组织在满足准入条件时可申请加入一个虚拟社区，在向社区贡献资源的同时也从社区中获取需要的资源。在这种分布、动态和开放的环境中，Web服务成为了社区交付资源的最主要手段。虚拟社区中用以共享资源的领域web服务具有高度的自治性，它们由其拥有者提供并维护，供其他社区用户共享使用，这些服务在逻辑上又形成了一个服务社区。传统的服务社区中，共享的服务为其提供者所拥有，其他成员对该服务“使用而不拥有”。社区中部分优势Web服务被请求的频率远高于其他服务，而web服务的自治性又决定了其宿主环境的不可变，导致了优势web服务的宿主资源严重过载，而有些服务由于通用性较低或者对应于边缘性的业务功能而很少被使用，其宿主资源又过于闲置。Web服务宿主资源利用率和服务质量保障等方面存在严重不足。云计算是一种基于互联网的、大众参与的、以服务方式提供的新型计算模式，其目的是实现资源共享与整合，其中计算资源是动态、可伸缩且被虚拟化的。云平台管理软件将整合的计算资源根据应用访问的具体情况进行动态调整，包括增大或减少资源的要求。因此云计算对于在非恒定需求的应用中具有非常好的应用效果，这种弹性的云服务可帮助用户在任意时间得到满足需求的计算资源。因此，结合云计算技术，在保持原有服务社区及既有应用不变的前提下，基于虚拟社区用户自治的web服务宿主资源构造一个小型云环境，使社区用户能够享受到云环境提供的服务质量，将是一个非常具有实际意义和应用价值的研究。综合上述考虑，本文提出了虚拟社区云的概念并定义了其分层模型，基于虚拟社区用户的基础设施，实现从服务社区向虚拟社区云的低成本过渡。另一方面，云环境下的服务质量一直是云计算领域研究的热点之一。虚拟社区云的基础设施由社区成员的空闲资源构成的虚拟资源池，云中以服务作为资源共享的基本单位。虚拟社区的开放性、web服务具有的自治性以及用户请求的并发性使得虚拟社区云在服务质量保障方面面临更大的挑战。针对这个问题，提出了一种的云服务副本放置策略，通过分析虚拟社区云的特征，，挖掘服务社区中各服务之间的内在联系，生成部分服务的副本并对其进行合理的预放置。通过实验仿真，验证了服务副本放置策略的有效性，实验表明它能有效缩短业务请求的响应时间，较大程度的提高了虚拟社区云的服务质量。
[Abstract]:In the research field of biological information, a large number of virtual communities have been formed through Internet technology in order to realize the sharing of related software and data resources in the field. Individuals or organizations engaged in research in a specific field may apply to join a virtual community when they meet the entry requirements, providing resources to the community at the same time as obtaining the needed resources from the community. In this distributed, dynamic and open environment, Web services become the primary means of community resource delivery. The domain web services used to share resources in virtual communities have a high degree of autonomy. They are provided and maintained by their owners and shared by other community users. These services logically form a service community. In a traditional service community, a shared service is owned by its provider, and other members "use and do not own the service." Some dominant Web services in the community are requested much more frequently than other services, and the autonomy of web services determines the immutability of their hosting environment, which leads to a serious overload of host resources of superior web services. However, some services are rarely used because of their low generality or marginal business functions, and their host resources are too idle. There are serious deficiencies in the utilization of Web services hosting resources and the guarantee of quality of service. Cloud computing is a new computing model based on Internet, popular participation and service mode. The purpose of cloud computing is to realize resource sharing and integration, in which computing resources are dynamic, scalable and virtualized. Cloud platform management software dynamically adjusts the integrated computing resources according to the specific conditions of application access, including increasing or reducing resource requirements. Therefore, cloud computing has a very good effect on applications with unsteady requirements. This flexible cloud service can help users to obtain computing resources to meet their requirements at any time. Therefore, combined with cloud computing technology, under the premise of keeping the original service community and existing applications unchanged, a small cloud environment is constructed based on the web service hosting resources of virtual community user autonomy. Making community users enjoy the quality of service provided by the cloud environment will be a study of practical significance and application value. Based on the above considerations, this paper puts forward the concept of virtual community cloud and defines its hierarchical model. Based on the infrastructure of virtual community users, the paper realizes the low-cost transition from service community to virtual community cloud. On the other hand, the quality of service (QoS) in cloud environment has been one of the hotspots in cloud computing. The infrastructure of the virtual community cloud is a virtual resource pool composed of the free resources of the community members. In the cloud, the service is regarded as the basic unit of resource sharing. The openness of virtual community and the concurrency of user requests make virtual community cloud face more challenges in quality of service assurance. In order to solve this problem, a cloud service replica placement strategy is proposed. By analyzing the characteristics of cloud in virtual community, the inherent relationship among the services in the service community is excavated, and the replica of some services is generated and reasonably pre-placed. The simulation results show that the service replica placement strategy is effective. The experimental results show that it can effectively shorten the response time of business requests and improve the service quality of virtual community cloud to a large extent.
【学位授予单位】：西北师范大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TP393.09

【共引文献】