基于有限自动机的Web服务行为的描述与发现

Web服务技术越来越成为应用和研究的热点,对Web服务的行为描述的几种方案进行比较分析,推荐了对原有限自动机定义进行扩展的方法,以达到准确地描述Web服务间的执行步骤和相互作用的目的。     

基于XYZ/ADL的Web服务组合描述与验证

Web服务组合是当前Web服务领域的一个研究热点,目前已有一些相关的描述与验证方法,本文从软件体系结构角度研究Web服务组合描述与验证方法.基于软件体系结构描述语言XYZ/ADL和精化检验/模型检测方法,提出了一种Web服务组合的描述与验证方法.XYZ/ADL是时序逻辑语言XYZ/E的扩展,考虑到多数Web服务具有实时特征,采用XYZ/E的实时扩展语言XYZ/RE表示系统应满足的时间约束.针对Web服务组合系统,根据XYZ/RE到时间自动机的映射规则将系统描述转换为对应的时间自动机,分别采用精化检验和模型检测两种技术验证Web服务组合的正确性;最后通过两个实例分析分别阐述了上述方法的可行性和有效性.     

基于上下文的Web服务动态组合

合成现有Web服务以生成功能更强更复杂的组合服务成为必然,组合服务的上下文信息具有十分重要的作用.针对Web服务描述语言仅支持服务功能性描述的不足,扩展了非功能属性描述,定义了一个Web服务的上下文模型,设计实现了感知上下文和执行动态服务替换的组合服务平台,通过运行旅游服务对该平台系统进行了有效验证.     

基于Sub Web Service服务组合方法

在当前Web服务动态组合研究的基础上,提出了一种基于Sub Web Service的混合Web服务组合方法。结合静态与动态服务组合方法,将动态生成的服务组合计划描述保存在缓冲池中,当用户使用该组合服务时,系统将会在缓冲池中搜寻此服务组合,并为请求调用它。在组合算法中提出了基于Sub Web Service的组合算法,将多输入多输出的Web服务分解为多输入单输出的Sub Web服务执行服务组合。在避免重复动态组合服务的基础上,减轻了Web服务在组合过程中对多输出接口的依赖性,提高了系统服务效率。     

基于MDA的语义Web服务的组合与验证

针对语义组合Web服务的验证问题,研究了模型验证相关技术、统一模型语言(UML),提出了基于模型驱动架构(MDA)的组合方法.该方法使用UML类图和用例图对OWL-S进行静态组合建模,使用活动图对OWL-S进行动态组合建模,实现了语义组合Web服务的UML描述,然后将该描述转换为Promela语言代码,在Promela代码之后增加LTL的声明,使用SPIN工具进行正确性、安全性和活性验证.该模型保证了组合过程的正确性.     

基于语义的Web服务动态组合框架的研究

提出一种基于语义的Web服务动态组合框架.根据服务接口之间的依赖关系,动态地确定服务组合,使用基于语义的概念匹配,完成服务接口之间的匹配.用户根据需求,确定输入输出参数,程序可以自动地确定服务组合,来满足用户的需求.     

动态电子商务系统构建中的服务发现和组合问题研究综述

在构建基于Web服务的分布式业务过程管理系统首先要解决两个关键问题:首先,必须搜索(发现)包含期望功能及操作需求的Web服务以实现给定目标任务;其次,在发现相关Web服务后,需要一定的机制来简化结构和语义的不同问题。在实现这两个任务的时候,面临着许多问题亟待解决。文章对动态电子商务系统构建中的服务发现和组合问题进行了文献综述,指出当前研究中存在的问题和有待研究的方向。     

多层次组合Web服务筛选方法

为了能够更好地满足用户对服务组合的需要,文中首先给出了多层次纽合Web服务的筛选模型,并将多层次组合Web服务筛选模型分为五个步骤。在此基础上将Web服务的属性分为功能属性和非功能属性（即QoS属性）。通过划分服务类对功能属性进行描述,并按照服务类以QoS属性的类型进行服务组合。最后给出了多目标方案筛选方法及其实验。     

基于服务分组和调用轨迹的Web服务组合验证方案

针对Web服务组合的有效性验证问题,提出了一种基于服务分组和调用轨迹的Web服务组合形式化验证方案。首先,基于服务调用顺序,利用提出的Web服务集分组(WSSG)算法将候选Web服务划分为几个子集,并结合调用轨迹编排这些子集组成WSSG图,作为系统的抽象模型;然后,推理出系统所需的预期交互规范,并利用线性时序逻辑(LTL)来描述交互规范;最后,通过检测模型是否符合交互规范来验证组合模型的可行性。实验结果表明,该方案能够有效验证Web服务组合的正确性,且避免了死锁现象。     

基于OWL-S的Web服务组合的验证研究

为保证基于OWL-S的Web服务组合的正确性和可靠性，验证组合服务的交互协议．采用一种三层体系结构思想，即以OWLS来组合服务，以GA模型为中间模型，以Promela模型为验证模型．设计和实现了服务组合模型到GA模型的转化，并将GA模型转化为Promela模型，最后利用SPIN工具完成验证。由于采用了中间模型．该方法具有极好的灵活性和可扩展性，并且较好地解决了Web服务的特征给模型验证带来挑战的问题。     

基于CSP的能耗高效云计算资源调度模型与算法

利用约束满足问题对异构云数据中心的能耗优化资源调度问题建模,通过求解建立的约束模型可以获得能耗最优的资源分配方式,并在此基础上提出了能耗优化的资源分配算法dynamicpower (DY)。与已有的算法MinPM、FFD、BFD相比,算法DY考虑了资源的异构性,能够降低云数据中心物理服务器的能耗。最后,利用Choco实现了提出的算法DY,并将DY与MinPM、FFD、BFD进行实验比较,实验结果表明,提出的算法在能耗上有明显优势。     

Study on virtual resource allocation optimization in cloud computing environment

Most existing researches of resource allocation in data center did not take into full consideration how to decrease energy consumption.The energy efficiency virtual resource allocation for cloud computing as a multi-objective optimization problem was formulated,which was then solved by intelligent optimization algorithm.The simulation results reveal that the strategy can successfully generate schedule scheme of different numbers of servers-VM with diverse characteristics and decrease the total operating energy of data center effectively.     

Pricing in combinatorial double auction-based grid allocation model

This article proposes a novel grid resource allocation model, in which the users and the grid service providers participate in the combinatorial double auction for the resource allocation. To obtain the detailed resource allocation status and the price information, a novel pricing algorithm is designed for the allocation model. Simulation results demonstrate that the proposed algorithm completes the resource allocation and pricing efficiently, and exhibits incentive compatible characteristic. Moreover,users with the higher average price and providers with the lower average price get compensation during the pricing process.     

Online combinatorial based mechanism for MEC network resource allocation

In this paper, the resource allocation problem for mobile edge computing (MEC) network is discussed. We focus on the design of online resource allocation strategy by considering the time‐varying demands of the combinatorial resources for the mobile users. To handle this issue, at first, a time splitting‐based online allocation mechanism is introduced. Then, for a given resource allocation period of the time splitting, a combinatorial auction mechanism for the combination resources allocation is proposed. We further prove that the proposed combinatorial auction is both individual rational and incentive‐compatible, and which can bring a higher revenue to the service provider. In order to verify the performance of the proposed mechanism, a variable‐relaxed‐based performance‐bound algorithm and a greedy optimization‐based suboptimal algorithm are presented for comparison purpose. Finally, the performance of these proposed algorithms are testified by numerical simulations, which confirm the analysis results.     

基于天线波束成形的OFDMA系统的自适应资源分配

对正交频分复用接入系统在多用户多天线传输情况下的自适应资源分配策略进行了研究,提出了一种基于天线波束成形的,包括动态子载波分配、自适应调制、比特加载的无线资源分配方案.算法的优化设计目标是在满足总的恒定传输比特数和误比特率性能要求的情况下,使得系统总的发射功率最小.仿真结果表明,由于多天线阵列增益和多用户分集增益,系统整体性能得到了明显的优化.     

Dynamic resource allocation in cloud download service

Cloud download service, as a new application which downloads the requested content offline and reserves it in cloud storage until users retrieve it, has recently become a trend attracting millions of users in China. In the face of the dilemma between the growth of download requests and the limitation of storage resource, the cloud servers have to design an efficient resource allocation scheme to enhance the utilization of storage as well as to satisfy users' needs like a short download time. When a user's churn behavior is considered as a Markov chain process, it is found that a proper allocation of download speed can optimize the storage resource utilization. Accordingly, two dynamic resource allocation schemes including a speed switching (SS) scheme and a speed increasing (SI) scheme are proposed. Both theoretical analysis and simulation results prove that our schemes can effectively reduce the consumption of storage resource and keep the download time short enough for a good user experience.     

Spectrum redistribution for cognitive radios using discriminatory spectrum double auction

With the reformation of spectrum policy and the development of cognitive radio, secondary users will be allowed to access spectrums licensed to primary users. Spectrum auctions can facilitate this secondary spectrum access in a market‐driven way. To design an efficient auction framework, we first study the supply and demand pressures and the competitive equilibrium of the secondary spectrum market, considering the spectrum reusability. In well‐designed auctions, competition among participants should lead to the competitive equilibrium according to the traditional economic point of view. Then, a discriminatory price spectrum double auction framework is proposed for this market. In this framework, rational participants compete with each other by using bidding prices, and their profits are guaranteed to be non‐negative. A near‐optimal heuristic algorithm is also proposed to solve the auction clearing problem of the proposed framework efficiently. Experimental results verify the efficiency of the proposed auction clearing algorithm and demonstrate that competition among secondary users and primary users can lead to the competitive equilibrium during auction iterations using the proposed auction framework. Copyright © 2011 John Wiley & Sons, Ltd.     

基于弹性资源调整的云计算资源分配方法

针对云计算环境中负载难以预测并且负载量实时变化的应用,设计了一种基于时间协同的资源分配方法,该方法在应用运行过程中,根据负载量以及任务处理时间,制定出多虚拟机协同的资源分配方案。该方法采用时间协同的方式有效实现了资源复用,提高了数据中心资源利用率,并进一步降低了数据中心的运维成本。     

UNIFORM—PRICE AUCTION FOR BANDWIDTH ALLOCATION IN THE INTERNET

It has been widely accepted that auctioning which is the pricing approach with minimal information requirement is a proper tool to manage scare network resources.Previous works focus on vickrey auction which is incentive compatible in classic auction theory.In the beginning of this letter,the faults of the most representative auction-based mechanisms are discussed.And then a new method called Uniform-Price Auction(UPA),which has the simplest auctiopn rule is proposed and its incentive compatibility in the network environment is also proved.Finally,the basic mode is extended to support applications which require minimum bandwidth guarantees for a given time period by introducing derivative market.and a market mechanism for network resource allocation which is predictable,riskless,and simple for eng-users is completed.     

Adaptive radio resource allocation for multiple traffic OFDMA broadband wireless access system

1 Introduction Next-generation wireless communication systems (systems beyond 3G) will be required to provide flexible and easy deployment solution to high-speed communications and to support a variety of services utilizing advanced multiple access techni…