基于改进BPSO的Web服务组合选择算法

为使现有Web服务组合的服务选择技术满足用户需求,提出一种基于改进二进制粒子群优化(BPSO)的服务选择算法。引入变异算子和线性递减惯性权重,解决传统二进制BPSO的早熟收敛问题,采用粒子记忆性对不满足约束条件的个体进行修正。实验结果表明,该算法能提高寻优效率。     

嵌入式软件中一种修正QoS值的构件选择方法

CBSD(Component-Based Software Development)已经成为嵌入式软件开发的主流技术。在嵌入式环境下,有大量功能相似的构件,在开发过程中基于QoS的构件选择已成为研究热点。然而这些构件的QoS声明与提供者给出的往往并不一致。为此,提出一种基于修正QoS值的构件选择方法,该方法将QoS信任度作为权重,修正QoS值,再结合模糊逻辑,推理出该构件的综合服务能力。通过嵌入式VOD仿真实验,验证了算法的有效性,保证了构件选择的客观性和准确性。     

信任感知的组合服务动态选择方法

把信任概念和信任度引入到服务组合中来,讨论了信任感知的服务组合选择问题,分别基于两种观点建立了其数学模型.并基于观点1,深入地研究了服务组合的动态选择问题,分别采用蚁群系统作为优化工具设计了两种动态选择方法:方法1针对服务在上限阈值的范围内提供优质服务,服务质量保持不变,超过阈值则拒绝服务的情况;方法2针对服务无限制地接受请求,但随着请求数量的增多,其服务质量下降的情况.通过对方法1和方法2的仿真实验结果分析表明,两种方法具有很好的效果.     

A P2P strategy for QoS discovery and SLA negotiation in Grid environment

In recent years, Grid systems and Peer to Peer networks are the most commonly-used solutions to achieve the same goal: the sharing of resources and services in heterogeneous, dynamic, distributed environments. Many studies have proposed hybrid approaches that try to conjugate the advantages of the two models. This paper proposes an architecture that integrates the P2P interaction model in Grid environments, so as to build an open cooperative model wherein Grid entities are composed in a decentralized way. In particular, this paper focuses on a QoS aware discovery algorithm for P2P Grid systems, analyzing protocol and explaining techniques used to improve its performance.     

Computational intelligence tools for next generation quality of service management

In this paper we explore the interest of computational intelligence tools in the management of heterogeneous communication networks, specifically to predict congestion, failures and other anomalies in the network that may eventually lead to degradation of the quality of offered services. We show two different applications based on neural and neuro-fuzzy systems for quality of service (QoS) management in next generation networks for voice and video service over heterogeneous Internet protocol (V2oIP) services. The two examples explained in this paper attempt to predict the communication network resources for new incoming calls, and visualizing the QoS of a communication network by means of self-organizing maps.     

Agent-based negotiation and decision making for dynamic supply chain formation

Modern businesses are facing the challenge of effectively coordinating their supply chains from upstream to downstream services. It is a complex problem to search, schedule, and coordinate a set of services from a large number of service resources under various constraints and uncertainties. Existing approaches to this problem have relied on complete information regarding service requirements and resources, without adequately addressing the dynamics and uncertainties of the environments. The real-world situations are complicated as a result of ambiguity in the requirements of the services, the uncertainty of solutions from service providers, and the interdependencies among the services to be composed. This paper investigates the complexity of supply chain formation and proposes an agent-mediated coordination approach. Each agent works as a broker for each service type, dedicated to selecting solutions for each service as well as interacting with other agents in refining the decision making to achieve compatibility among the solutions. The coordination among agents concerns decision making at strategic, tactical, and operational level. At the strategic level, agents communicate and negotiate for supply chain formation; at the tactical level, argumentation is used by agents to communicate and understand the preferences and constraints of each other; at the operational level, different strategies are used for selecting the preferences. Based on this approach, a prototype has been implemented with simulated experiments highlighting the effectiveness of the approach.     

一种面向QoS的Web服务组测试方法TF

Web服务及SOA技术的出现为Web应用架构提供了一个新的范式.未来会有大量功能相同或相近的Web服务,如何从中优选出符合用户需要的Web服务已成为一个正在研究的问题.在研究了现有的Web服务组中Web服务优选方法基础上,针对其仅局限于功能优选的不足,提出了一种面向QoS的Web服务组中Web服务优选方法.在定义Web服务QoS向量特征分量、QoS向量、最大相似度、QoS测试预言、QoS向量特征分量测试预言等参数基础上,基于层次聚类思想实现QoS向量聚类,依据最大相似度控制聚类层次,之后利用QoS测试预言、QoS向量特征分量测试预言及决策树实现优选.实验结果表明该方法是有效的,克服了以前的方法仅限于功能优选的局限性.     

基于性能需求的自适应中间件框架

分析影响服务质量的构件资源需求与资源依赖关系模型,提出一种自适应中间件框架。该框架能动态感知负载变化,自适应调整服务器配置参数,确保应用的服务质量。采用回溯算法搜索最优配置,以满足性能需求。以一个信息查询系统作为测试用例进行实验,结果表明,该框架可以提高应用程序的性能。