企业信息化新途径：“云”计算

＂云＂计算是指在互联网上的一组虚拟化的计算机资源以及相关的服务,用户根据使用这些资源的多少或时间长短支付费用。采用＂云＂计算将大幅提高企业信息化水平,有效降低信息技术使用或管理等成本,促进企业在市场上的竞争能力。     

面向云计算的虚拟系统验证框架

本文针对面向需求的云计算提出了一种虚拟系统验证框架。该框架包括六中测试类型:功能测试、性能测试、可扩展性测试、压力测试、容错检验和功耗测试。框架给出了每种测试的测试目标、方法和过程。最后,本文进行了多种性能测试,并给出了测试结果和分析。     

Modelling Off-the-Shelf Information Systems Requirements: An Ontological Approach

Requirements for choosing off-the-shelf information systems (OISR) differ from requirements for development of new information systems in that they do not necessarily provide complete specifications, thus allowing flexibility in matching an existing IS to the stated needs. We present a framework for OISR conceptual models that consists of four essential elements: business processes, business rules, information objects and required system services. We formalise the definitions of these concepts based on an ontological model. The ontology-based OISR model provides a framework to evaluate modelling languages on how appropriate they are for OISR requirements specifications. The evaluation framework is applied to the Object-Process Methodology, and its results are compared with a similar evaluation of ARIS. This comparison demonstrates the effectiveness of the ontological framework for evaluating modelling tools on how well they can guide selection, implementation and integration of purchased software packages.     

An Operational Approach to Requirements Specification for Embedded Systems

The approach to requirements specification for embedded systems described in this paper is called "operational" because a requirements specification is an executable model of the proposed system interacting with its environment. The approach is embodied by the language PAISLey, which is motivated and defined herein. Embedded systems are characterized by asynchronous parallelism, even at the requirements level; PAISLey specifications are constructed by interacting processes so that this can be represented directly. Embedded systems are also characterized by urgent performance requirements, and PAISLey offers a formal, but intuitive, treatment of performance.     

浅谈企业云计算化与实施方案

针对企业电商业务的不断扩展的现况,自身网站架构已无法满足日益增长的需求.架构扩展成为很多企业IT部门的重要工作.企业如果选择在自己原基础设备上做扩展,会面临成本投入高,技术门槛高等等的问题,为了解决这些问题,云计算概念也随之应运而生,大型门户网站首当其冲成为了云计算服务提供商.就目前国内主要云计算类型进行介绍,企业用户可根据自身现况选择适合自己的云计算平台,来应付日益增长的各种弹性需求.     

一种高能效自适应移动云计算资源发现算法

针对移动云计算中资源发现能耗高的问题,提出了一种自适应、自动切换资源发现模式的高能效资源发现算法.首先,为两种主流移动资源发现模式分别建立能耗-资源质量模型;然后,利用启发式算法自适应的选择并切换至较低能耗的资源发现模式;最终,设备始终处于能耗较低的模式高效的实现资源发现.实验结果表明,本算法的能效高于单模式资源发现算法.     

面向云环境的自适应集群调整方法

应用服务器集群是平台即服务(platform as a service,PaaS)模式的主要运行环境。针对云环境下动态变化的用户负载和共享、异构的集群环境,提出一种自适应集群调整方法,根据集群负载状况实现资源按需供给。该方法建立了PaaS平台的性能分析模型,并据此提出自适应的资源供给机制和负载均衡机制。实验结果表明,通过调节集群节点逻辑资源池的大小和集群节点数量,配合自适应负载均衡方法,达到了资源按需供给的目的。     

一种云计算环境下的能效模型和度量方法

提出一种云计算环境下的能效模型和度量方法.首先定义了能效的数学表达及其测量和计算方法,并推导出了能效最大值的发生条件;其次,为方便能效计算,改进了计算机功率和CPU工作状态之间关系的数学表达,通过CPU使用率和频率来计算能效,从而简化了能效测量方法,此外,还设计并实施了大量实验,验证了提出的能效模型的正确性;同时对单机环境,云计算环境中CPU密集型、I/O密集型和交互型运算进行能效评估,总结其能效规律和优化办法,理论和实验证明,所提出的能效模型和计算方法能够准确地评估云系统的能效,并为能效优化奠定基础.     

Toward Cloud Computing QoS Architecture: Analysis of Cloud Systems and Cloud Services

Cloud can be defined as a new computing paradigm that provides scalable, on-demand, and virtualized resources for users. In this style of computing, users can access a shared pool of computing resources which are provisioned with minimal management efforts of users. Yet there are some obstacles and concerns about the use of clouds. Guaranteeing quality of service (QoS) by service providers can be regarded as one of the main concerns for companies tending to use it. Service provisioning in clouds is based on service level agreements representing a contract negotiated between users and providers. According to this contract, if a provider cannot satisfy its agreed application requirements, it should pay penalties as compensation. In this paper, we intend to carry out a comprehensive survey on the models proposed in literature with respect to the implementation principles to address the QoS guarantee issue.      

基于免疫机理的计算系统性能监控和评估

对于分布式高性能计算系统来说,模拟免疫机理实现计算系统的性能监控和评估是一个崭新的研究途径.分析和比较了免疫机理和计算系统抗衰之间的异同,构建了基于多Agent的系统抗衰逻辑模型,模拟免疫机理对计算系统的性能进行监控、诊断和建立性能衰退的数学模型,并在仿真实验中评价了性能监控对于所监控的计算节点的影响.在此基础上以一个音像资源事务处理系统为背景进行了应用研究,给出了一个两阶段超指数分布的数学模型来评估性能.仿真实验和应用研究的结果表明方法是有效可行的.     

Confidentiality Protection in Cloud Computing Systems

Current cloud computing systems pose serious limitation to protecting users'' data confidentiality. Since users'' sensitive data is presented in unencrypted forms to remote machines owned and operated by third party service providers, the risks of unauthorized disclosure of the users'' sensitive data by service providers may be high. Many techniques for protecting users'' data from outside attackers are available, but currently there exists no effective way for protecting users'' sensitive data from service providers in cloud computing. In this paper, an approach is presented to protecting the confidentiality of users'' data from service providers, and ensures that service providers cannot access or disclose users'' confidential data being processed and stored in cloud computing systems. Our approach has three major aspects: 1) separating software service providers and infrastructure service providers in cloud computing, 2) hiding information of the owners of data, and 3) data obfuscation. An example to show how our approach can protect the confidentiality of users'' data from service providers in cloud computing is given. Experimental results are presented to show that our approach has reasonable performance.     

DAACS : a Decision Approach for Autonomic Computing Systems

The Journal of Supercomputing - Systems running in ubiquitous environments are characterized by a context that changes frequently. The adaptation of this kind of systems according to the context is...     

云计算与云存储技术的企业应用分析

作为以互联网为计算平台的云计算,将会更广泛地涉及到海量数据处理任务.海量数据处理指的是对大规模数据的计算和分析.在互联网时代,互联网数据的统计和分析很多是海量数据级别的,为企业的数据储存提供了重要的服务.本文分析了云计算的应用类型,介绍了云计算的基础设施,深入分析了云计算与企业应用之间的关系.     

基于社区模型的云资源监测

云计算是一种新兴的商业计算模型,资源性能和负载监测是其重要的研究点。分析了传统的分布式计算资源监测策略,针对云计算环境,引入社区模型设计了层次式社区监测,提出了基于敏感因子的监测方法,以解决全局监控可能会带来的数据繁冗和无效问题。仿真实验表明,模型和策略在理论上是合理的,在效率上较传统监测系统有一定的提高。     

Metasystems: An Approach Combining Parallel Processing and Heterogeneous Distributed Computing Systems

A metasystem is a single computing resource composed of a heterogeneous group of autonomous computers linked together by a network. The interconnection network needed to construct large metasystems will soon be in place. To fully exploit these new systems, software that is easy to use, supports large degrees of parallelism, and hides the complexity of the underlying physical architecture must be developed. In this paper we describe our metasystem vision, our approach to constructing a metasystem testbed, and early experimental results. Our approach combines features from earlier work on both parallel processing systems and heterogeneous distributed computing systems. Using the testbed, we have found that data coercion costs are not a serious obstacle to high performance, but that load imbalance induced by differing processor capabilities can limit performance. We then present a mechanism to overcome load imbalance that utilizes user-provided callbacks.     

基于云计算的网络测量方法研究

随着网络技术的飞速发展,网络流量数据呈指数级增长,目前常用的集中式网络测量方法已经很难满足要求.论文提出一种基于云计算的网络测量系统,设计了基于数据报文的往返时延计算和Netflow流聚合的MapReduce算法,用于解决海量测量数据处理,实验结果表明该算法具有较好的正确性和可扩展性.     

Data-Intensive Cloud Computing: Requirements, Expectations, Challenges, and Solutions

Data-intensive systems encompass terabytes to petabytes of data. Such systems require massive storage and intensive computational power in order to execute complex queries and generate timely results. Further, the rate at which this data is being generated induces extensive challenges of data storage, linking, and processing. A data-intensive cloud provides an abstraction of high availability, usability, and efficiency to users. However, underlying this abstraction, there are stringent requirements and challenges to facilitate scalable and resourceful services through effective physical infrastructure, smart networking solutions, intelligent software tools, and useful software approaches. This paper analyzes the extensive requirements which exist in data-intensive clouds, describes various challenges related to the paradigm, and assess numerous solutions in meeting these requirements and challenges. It provides a detailed study of the solutions and analyzes their capabilities in meeting emerging needs of widespread applications.     

Requirements and GitHub Issues: An Automated Approach for Quality Requirements Classification

Programming and Computer Software - In the development of quality software, critical decisions related to planning, estimating, and managing resources are bound to the correct and timely...     

MobiByte: An Application Development Model for Mobile Cloud Computing

Mobile cloud computing presents an effective solution to overcome smartphone constraints, such as limited computational power, storage, and energy. As the traditional mobile application development models do not support computation offloading, mobile cloud computing requires novel application development models that can facilitate the development of cloud enabled mobile applications. This paper presents a mobile cloud application development model, named MobiByte, to enhance mobile device applications’ performance, energy efficiency, and execution support. MobiByte is a context-aware application model that uses multiple data offloading techniques to support a wide range of applications. The proposed model is validated using prototype applications and detailed results are presented. Moreover, MobiByte is compared with the most recent application models with a conclusion that it outperforms the existing application models in many aspects like energy efficiency, performance, generality, context awareness, and privacy.     

一种基于云计算的SaaS组装方法研究

根据基于云计算的SaaS(Software as a Service)软件的集成性、可配置性和定制性(简称IIC)所面临的问题.提出一种基于云计算的SaaS组装和质量方法:首先建立一种SaaS寻址方法和组装中断方法,以保证SaaS组装连续性和确定性;并根据寻址和中断情况建一种适合SaaS的相似度计算方法,以满足整个SaaS组装流程的精确性.其次根据SaaS的寻址组装和中断的情况,从Web服务质量、地址数量和分布、可用性、资源共享度、互操作性和ICC等角度建立SaaS组装质量模型,即QoSaaS(Quarry of SaaS).第三,在寻址中断支持和QoSaaS驱动下,构建一种SaaS组装算法.最后在Amazon下以一个SaaS销售软件生成为例进行分析,并给出一组数据验证表明该方法的可行性和有效性.