Advance reservations for predictive service in the Internet

We extend a measurement-based admission control algorithm suggested for predictive service to provide advance reservations for guaranteed and predictive service, while retaining the attractive features of predictive service. The admission decision for advance reservations is based on information about flows that overlap in time. For flows that have not yet started, the requested values are used, and for those that have already started measurements are used. This allows us to estimate the network load accurately for the near future. To provide advance reservations we ask users to include durations in their requests. We present simulation results to show that predictive service with advance reservations provides utilization levels significantly higher than those for guaranteed service, and comparable to those for predicted service without advance reservations. Those utilization levels are reached without any preemption of other admitted flows. Finally, we discuss how to setup advance reservations over multiple hops in the Internet using resource reservation setup protocols.     

云服务相关问题研究

"云计算"与网络的发展脱不开关系。有线网络的大提速以及无线网络3G乃至4G的普及,共同编织了能让"云"茁壮成长的环境。"网络即电脑"这一概念,现在正从近乎预言的概念慢慢变成现实。在个人应用领域,"云"正以怎样的形式影响日常生活呢?通过对云服务的简要概述,探讨云服务中存在的若干问题。     

Agent-based Cloud service composition

Service composition in multi-Cloud environments must coordinate self-interested participants, automate service selection, (re)configure distributed services, and deal with incomplete information about Cloud providers and their services. This work proposes an agent-based approach to compose services in multi-Cloud environments for different types of Cloud services: one-time virtualized services, e.g., processing a rendering job, persistent virtualized services, e.g., infrastructure-as-a-service scenarios, vertical services, e.g., integrating homogenous services, and horizontal services, e.g., integrating heterogeneous services. Agents are endowed with a semi-recursive contract net protocol and service capability tables (information catalogs about Cloud participants) to compose services based on consumer requirements. Empirical results obtained from an agent-based testbed show that agents in this work can: successfully compose services to satisfy service requirements, autonomously select services based on dynamic fees, effectively cope with constantly changing consumers’ service needs that trigger updates, and compose services in multiple Clouds even with incomplete information about Cloud participants.     

A service acquisition mechanism for server-based heterogeneousdistributed systems

This paper presents a mechanism that facilitates and enhances the use of independently administered remote network servers in the presence of server interface heterogeneity. The mechanism is designed under the client-service model, which extends the client-server model with an abstraction of service to decouple abstract server capabilities from concrete server interface specifics such as server interface binding protocols and the interface operation invocation protocols. The mechanism selects servers, accommodates server interface heterogeneity, and handles server access failures as per the abstract server capabilities desired by the client. It could return the identity of the server used for each service access invocation to facilitate billing, refining service specifications, and reporting server-specific errors. This paper also illustrates a C library interface to this mechanism, and describes a language veneer over the C programming language demonstrating how a typed procedural language could be extended by a few language constructs to support the mechanism under the client-service model. In this language, server capabilities are referenced by abstract data type (ADT) objects, and are accessed by invoking the objects' interface operations using a call-by-value-result paradigm     

Cloud computing service composition: A systematic literature review

The increasing tendency of network service users to use cloud computing encourages web service vendors to supply services that have different functional and nonfunctional (quality of service) features and provide them in a service pool. Based on supply and demand rules and because of the exuberant growth of the services that are offered, cloud service brokers face tough competition against each other in providing quality of service enhancements. Such competition leads to a difficult and complicated process to provide simple service selection and composition in supplying composite services in the cloud, which should be considered an NP-hard problem. How to select appropriate services from the service pool, overcome composition restrictions, determine the importance of different quality of service parameters, focus on the dynamic characteristics of the problem, and address rapid changes in the properties of the services and network appear to be among the most important issues that must be investigated and addressed. In this paper, utilizing a systematic literature review, important questions that can be raised about the research performed in addressing the above-mentioned problem have been extracted and put forth. Then, by dividing the research into four main groups based on the problem-solving approaches and identifying the investigated quality of service parameters, intended objectives, and developing environments, beneficial results and statistics are obtained that can contribute to future research.     

A PSO-based intelligent service dispatching mechanism for customer expectation management

In the era of experience economy, service providers have to provide customers with high quality service experience in order to attract more customers and achieve higher customer satisfaction. Managing customer expectation is a critical approach for service providers to consider. Although customer expectation has been discussed across different research disciplines, to our knowledge, there is still no systematical and feasible way to apply customer expectation management into real environments. This study attempts to establish an intelligent service dispatching mechanism by using particle swarm optimization for customer expectation management. This mechanism can help service providers design and deliver satisfactory service experience to customers. In order to evaluate the effectiveness and robustness of this mechanism, this study employs micro- and macro-simulation experiments to confer and analyze its performance. The simulation results show service providers can gain benefit and raise customer satisfaction by managing customer expectation during service experience delivery. Meanwhile, customers can also receive memorable experiences and have positive responses to service providers and other customers. Consequently, a high performance ecosystem within service providers and customers can be formed.     

Online algorithms for advance resource reservations

We consider the problem of providing QoS guarantees to Grid users through advance reservation of resources. Advance reservation mechanisms provide the ability to allocate resources to users based on agreed-upon QoS requirements and increase the predictability of a Grid system, yet incorporating such mechanisms into current Grid environments has proven to be a challenging task due to the resulting resource fragmentation. We use concepts from computational geometry to present a framework for tackling the resource fragmentation, and for formulating a suite of scheduling strategies. We also develop efficient implementations of the scheduling algorithms that scale to large Grids. We conduct a comprehensive performance evaluation study using simulation, and we present numerical results to demonstrate that our strategies perform well across several metrics that reflect both user- and system-specific goals. Our main contribution is a timely, practical, and efficient solution to the problem of scheduling resources in emerging on-demand computing environments.     

云服务安全性与可靠性的浅析

随着互联网的不断发展盛行,人类社会进入信息化时代.众多先进的信息技术不断被人们应用于生活的各个领域,它们不仅使人们的生活得到了很大改善,为人们的生活提供了很多便利之处,而且让网络技术得到了更广泛地发展、应用.然而,云服务在被人们使用的过程中出现了很多用户信息遗失和泄露等安全风险,云服务的安全性和可靠性受到人们的质疑.本文通过对云服务的安全性和可靠性进行思考,并借由学校云服务的运用探究云服务未来的发展.     

Disaster avoidance mechanism for content-delivering service

Many software applications have been developed on client-server and web-based architectures, with client software installed in numerous clerks’ devices spread over the whole of Taiwan along the hierarchical organization of large-scaled service companies. The damage for a large-scaled service company would be caused by an inconsistent system, in which client software fails to receive updated content causing loss of emergency calls and possibility of recovery. Therefore, a reliable content-delivering service is needed for such a large-scaled service company to ensure system consistency whenever a disaster occurs. This study analyses the error situations of a proposed content-delivering service that has been implemented in a large-scaled company in Taiwan. Moreover, its disaster avoidance mechanism provides a reliability model with the waiting-time distribution of disconnected links. The proposed disaster avoidance mechanism prevents damage from terminating operations of a company caused by disasters, such as earthquakes, tsunamis, nuclear plant explosions or wars. Empirical results demonstrate that the proposed design run on 19 servers distributes content with less than 3.4 content-delivery failures per million hours.     

A token-bucket based notification traffic control mechanism for IMS presence service

Presence is a service that allows a user to be informed about the specified state of another user. Presence service has become a key enabler for next-generation applications such as instant messaging, push-to-talk and web2.0. However, recent studies show that the notification traffic of presence service causes heavy signaling load on IP multimedia subsystem (IMS) network. This paper introduced a token-bucket based notification traffic control (TNTC) mechanism, which is an application layer solution deployed at the presence server. The TNTC aims at upgrading valid access probability while controlling the notification traffic. A mathematical model of a queuing system is proposed to describe TNTC. We analyzed its main probability features and investigated the effects of different parameters on the performance of TNTC. Extensive simulations verified that TNTC can effectively control notification traffic and perform better than the existing schemes in terms of valid access probability and update arrival rate.     

A novel resource allocation mechanism for live cloud-based video streaming service

With the recent emergence of cloud computing, growing numbers of clients are using online cloud services through the Internet such as video streaming service. The rent costs of cloud service providers increase when the resource utilizations of the cloud-servers are not well. Therefore, resource allocation is a crucial problem for cloud data centers. The resource allocation problem is an NP-hard problem. This paper proposes a novel cloud resource allocation mechanism based on a winning strategy for a Nim game. This mechanism offers all clients an effective number of running cloud servers, and allocates cloud resources rapidly and effectively by using a pre-pairing approach. The proposed mechanism does not require searching for remaining resources of the running cloud server; hence, it can reduce the time taken to arrange resources. The experimental results show that the proposed mechanism can improve utilization of cloud servers and reduce the rent costs of the cloud service providers. The proposed mechanism can reach the utilization of cloud servers by as much as 99.96 %. The proposed mechanism is approximately 9 % more efficient than the market-based grid resource allocation algorithm, and 19 % more efficient than the modified best fit decreasing algorithm.

     

Advance reservations for service-aware GMPLS-based optical networks

In service-oriented networks, cooperation between users, applications and network tends to come closer. With this objective, new architectures arise to cope with the upcoming demands. Of great importance is the definition of the proper interfaces and network services. One of these new services is known as the Advance Reservation Service. This service allows prior reservation of network resources in order to provide guaranteed client connections. The introduction of advance reservations in heterogeneous transport networks imposes the need to find new mechanisms that consider temporal characteristics of scheduled connections and their impact on immediate connections. In this paper, we investigate these issues, propose novel algorithms to improve overall network performance, and describe the implementation carried out over the ASON/GMPLS CARISMA testbed.     

Cloud federation in a layered service model

We show how a layered Cloud service model of software (SaaS), platform (PaaS), and infrastructure (IaaS) leverages multiple independent Clouds by creating a federation among the providers. The layered architecture leads naturally to a design in which inter-Cloud federation takes place at each service layer, mediated by a broker specific to the concerns of the parties at that layer. Federation increases consumer value for and facilitates providing IT services as a commodity. This business model for the Cloud is consistent with broker mediated supply and service delivery chains in other commodity sectors such as finance and manufacturing. Concreteness is added to the federated Cloud model by considering how it works in delivering the Weather Research and Forecasting service (WRF) as SaaS using PaaS and IaaS support. WRF is used to illustrate the concepts of delegation and federation, the translation of service requirements between service layers, and inter-Cloud broker functions needed to achieve federation.     

Cloud based intelligent system for delivering health care as a service

The promising potential of cloud computing and its convergence with technologies such as mobile computing, wireless networks, sensor technologies allows for creation and delivery of newer type of cloud services. In this paper, we advocate the use of cloud computing for the creation and management of cloud based health care services. As a representative case study, we design a Cloud Based Intelligent Health Care Service (CBIHCS) that performs real time monitoring of user health data for diagnosis of chronic illness such as diabetes. Advance body sensor components are utilized to gather user specific health data and store in cloud based storage repositories for subsequent analysis and classification. In addition, infrastructure level mechanisms are proposed to provide dynamic resource elasticity for CBIHCS. Experimental results demonstrate that classification accuracy of 92.59% is achieved with our prototype system and the predicted patterns of CPU usage offer better opportunities for adaptive resource elasticity.     

基于SLA的云服务信任管理研究

随着云计算的快速发展,云服务安全问题亟待解决,其中信任管理是其研究重点。将SLA协议引入到信任管理中,实时监测SLA参数,分析信任度管理,建立信任管理框架。并以不同的角度分析了SLA参数的类型和SLA参数的可信度,最终形成全面、动态的信任评估。     

面向服务架构的云计算平台

介绍了云计算的定义和服务模式,阐述了目前信息化管理和架构中存在的普遍问题,结合面向服务的软件架构技术发展现状,提出融合面向服务架构( SOA)技术的云计算服务平台,对于信息化建设中降低成本、系统重整和业务重组具有战略意义。     

基于云计算的测试公共服务平台设计技术

分析了国内软件质检行业资源聚合面临的问题,提出了采用云计算技术聚合各软件质检机构资源的方案,设计并实现了基于云计算技术的公共测试服务平台,该平台通过测试云服务方式以统一的接口推动国内软件质检资源共享,并为软件质检机构提供了一种新的业务模式。     

A robust e-commerce service: Light-weight secure mail-order mechanism

Mail order systems offer a convenient purchase service, in which buyers need not visit the store physically and instead choose what they want via a table of contents. Without a third party to play the roles of verifier and recorder, however, buyers face a potential problem of being cheated by a malicious seller. Thus, we aim to develop a mail order system over the Internet that can guarantee user anonymity and secrecy during the transaction process. The low computation of the mutual authentication between the parties involved contributes to the practicality of this new system, while the correctness of this process can be confirmed by the BAN logic model.     

A synergetic mechanism for digital library service in mobile and cloud computing environment

Digital library services in the mobile computing have come into our daily life with the development of wireless communication and the manufacture of mobile devices. Digital libraries have collected large-scaled data for providing information service. However, there are still many problems such as limitations of computing on mobile devices and data transmission problems in the wireless network. This paper proposes a synergetic mechanism for digital library to provide information service in the mobile and cloud computing environment, which combines the digital library servers, mobile hosts and personal cloud space into a synergetic work group seamlessly. The proposed mechanism integrates the strong computing and large-scaled storage ability of cloud computing together with the convenience of mobile computing. It could help promoting knowledge sharing and improve work efficiency of users in the mobile and cloud computing environment.