基于Spring Cloud的企业级智慧后勤保障平台

立足于新时代后勤管理机制与服务保障模式实际需求, 为打造具有业务集约化、应用智能化、数据融合化特征的智慧后勤, 推进后勤工作提质增效, 强化后勤精益管理水平, 实现后勤管理和服务的信息化、数字化、智能化转型升级, 本文基于微服务的实现技术Spring Cloud开发了企业级智慧后勤保障平台. 此平台通过整合各类后勤资源, 涵盖后勤管理中心、服务保障中心、物业监控中心3大中心, 面向企业后勤管理人员、物业人员、员工提供智慧食堂、便捷出入、物业管理等全方位后勤保障服务, 打破传统单体式后勤业务应用系统间壁垒, 实现各类后勤业务应用系统数据贯通, 进一步提升后勤保障能力和管理效率.     

一种有效负载均衡的网格Web服务体系结构模型

基于Web服务资源的小世界模型,提出了一种可无缝结合网格OGSA框架的Web服务体系结构与动态的资源负载均衡分配模型,它以Web服务资源注册中心(Web Services Resource Register Center,WSRRC)作为Web服务资源查找的入口,以Web服务资源ID类形成的虚拟资源树作为资源逻辑组织与负载均衡分配结构,以小世界形成的区域代理自治系统(Area Proxy Autonomy System．APAS)来进行Web服务资源的维护．并详细描述了该模型的实现机制、组织协议与数据结构,着重研究了逻辑资源树负载信息的传播机制及负载均衡策略,模拟试验表明该模型是合理而有效的：它可以在较小开销下获得较满意的资源组织与定位性能,能适应网格Web服务资源的异构、复杂与动态性,具有良好的可扩展性及保持全局网络负载均衡的良好性能．     

On optimal decision for QoS-aware composite service selection

The increasing popularity of employing web services for distributed systems contributes to the significance of service discovery. However, duplicated and similar functional features existing among services require service consumers to include additional aspects to evaluate the services. Generally, the service consumers would have different view on the quality of service (QoS) of service attributes. How to select the best composite service in theory among available service (WS) candidates for consumers is an interesting practical issue. This work proposes a QoS-aware service selection model based on fuzzy linear programming (FLP) technologies, in order to identify their dissimilarity on service alternatives, assist service consumers in selecting most suitable services with consideration of their expectations and preferences. This approach can obtain the optimal solution of consensual weight of QoS attribute and fuzzy positive ideal solution (FPIS) by extending LINMAP method, developed by Srinivasan and Shocker. Finally, two numerical examples are given to demonstrate the process of QoS-aware web service selection. The experimental results demonstrated that it is a feasible and supplementary manner in selecting the of web services.     

一种用户需求驱动的服务资源建模方法

面向用户需求通过松散耦合的服务资源的重用和重组,实现其按需发现与组合,正成为网络化软件主流的开发范型。如何对服务进行建模已成为这种范型中的一个重要问题。提出一种用户需求驱动、基于RGPS(Role-Goal-Process-Service)领域资产的服务建模方法。通过对服务模型进行语义需求封装来满足用户需求,从而实现用户需求和服务之间的动态"握手"。该方法已在原型系统中得以应用和验证。     

Hybrid shuffled frog leaping algorithm for energy-efficient dynamic consolidation of virtual machines in cloud data centers

Cloud computing aims to provide dynamic leasing of server capabilities as scalable virtualized services to end users. However, data centers hosting cloud applications consume vast amounts of electrical energy, thereby contributing to high operational costs and carbon footprints. Green cloud computing solutions that can not only minimize the operational costs but also reduce the environmental impact are necessary. This study focuses on the Infrastructure as a Service model, where custom virtual machines (VMs) are launched in appropriate servers available in a data center. A complete data center resource management scheme is presented in this paper. The scheme can not only ensure user quality of service (through service level agreements) but can also achieve maximum energy saving and green computing goals. Considering that the data center host is usually tens of thousands in size and that using an exact algorithm to solve the resource allocation problem is difficult, the modified shuffled frog leaping algorithm and improved extremal optimization are employed in this study to solve the dynamic allocation problem of VMs. Experimental results demonstrate that the proposed resource management scheme exhibits excellent performance in green cloud computing.     

Globally optimal selection of web composite services based on univariate marginal distribution algorithm

Quality of service (QoS) model of composite services and web service selection based on QoS are currently the hot issues in the web service composition area. Service selection based on QoS, which is a globally optimal selection issue, is a NP-hard problem. Taking engine into consideration, this paper develops a QoS model for service selection in the web composite services. We use the algorithm on the estimation of distribution to solve the NP-hard problem of service selection and present a web service selection method based on the univariate marginal distribution algorithm (UMDA). Simulation analysis and experimental study based on the UMDA method are carried out. It is proved that the method is effective in solving the NP-hard problem.     

面向Web服务工作流系统的访问控制模型

提出了一种面向Web服务工作流系统的访问控制模型（WSWF-RBAC）。在基于角色的访问控制模型基础上引入系统资源的概念,把Web服务对象、属性和其它功能模块当做资源统一管理。引XT资源访问模式的概念,在约束条件下通过与资源的运算生成系统权限,从而实现了对权限的精细管理和动态调整能力。通过扩展web服务访问的角色集和用户集,并引入角色扮演对象,实现了工作流系统中Web服务与其它模块访问控制的一致性。将该模型应用于库房供应链系统中,运行结果表明,该模型能够增强Web服务工作流系统授权的灵活性和安全性。     

Cloud services selection: A systematic review and future research directions

Cloud computing has developed in popularity as a large-scale computing paradigm that offers a range of computing resources as a service through the internet on a pay-as-you-go basis. The expansion in demand and commercial availability of cloud services brings new challenges to cloud services selection. Several research studies have been conducted to develop enhanced methodologies to assist service consumers in selecting appropriate services. In this paper, 105 primary studies published during January, 2011 to May, 2022 has been selected using a multi-stage scrutinizing approach. The selected preliminary studies were further classified based on various variables to answer the research questions stated for this work. A systematic review of existing cloud service selection approaches is performed, which are analyzed along eight dimensions: decision-making methods, context, purposes, cloud service performance parameters, simulation/language tools, domain, datasets, and experiment/validation methods. After a thorough review and comparison of these approaches across the above-mentioned dimensions, several open research issues in the current literature have been identified. The contribution of this research is fourfold: focusing on state-of-the-art cloud services selection approaches, highlighting the benefits and drawbacks of various cloud services selection methodologies and their future directions, offering a taxonomy based on a thorough literature study, and identifying nine critical challenges in cloud services selection that require further investigation. This systematic review study is anticipated to benefit both academics and business experts.     

Composing web services enacted by autonomous agents through agent-centric contract net protocol

ContextAgents are considered as one of the fundamental technologies underlying open and dynamic systems that are largely enabled by the semantic web and web services. Recently, there is a trend to introduce the notion of autonomy empowered by agents into web services. However, it has been argued that the characteristics of autonomy will make agents become available intermittently and behave variedly over time, which therefore increase the complexity on devising mechanisms for composing services enacted by autonomous agents.ObjectiveIn this work, we propose an extension to Contract Net protocol, called Agent-centric Contract Net Protocol (ACNP), as a negotiation mechanism with three key features for composing web services enacted by autonomous agents.Method(1) A matchmaking mechanism embedded in a middle agent (as a service matchmaker) for discovering web services that are available intermittently is presented based on the concept of agent roles; (2) A selection algorithm based on risk-enabled reputation model (REAL) embedded in a manager agent (as a service composer) is introduced to serve a basis for selecting web services with variant performance; and (3) A negotiation mechanism between a manager agent and contractor agents (as atomic services) is devised and enables both a service composer and the atomic services to request, refuse or agree on adapting changes of services.ResultsThe problem of assembling a computer is discussed in this paper.ConclusionIt is increasingly recognised that web services would become more autonomous by introducing diverse agent technologies to better constitute more complex systems in open and dynamic environments. As web service technologies are best exploited by composite services, it is imperative to devise mechanisms for composing services of autonomy.     

基于负载均衡的Web服务双向选择方案

随着Web服务的广泛应用,如何在有限的资源下来提高Web服务的QoS(quality of service)已经成为关注的热点问题.通过设计一个灵活的选择结构BS-Serv(bidirectional selection-serv),提供者使用多维背包算法,请求者使用需要等待时间原则,来实现提供者和请求者的双向选择,从而即保证了提供者的资源能达到最充分的利用,提高了Web服务的QoS,还保证了请求者对服务的满意.详细分析了多维背包算法和请求者需要等待原则的设计,并讨论了结构的实现.     

Research on resource allocation for multi-tier web applications in a virtualization environment

Resource allocation for multi-tier web applications in virtualization environments is one of the most important problems in autonomous computing. On one hand, the more resources that are provisioned to a multitier web application, the easier it is to meet service level objectives (SLO). On the other hand, the virtual machine which hosts the multi-tier web application needs to be consolidated as much as possible in order to maintain high resource utilization. This paper presents an adaptive resource controller which consists of a feedback utilization controller and an auto-regressive and moving average model (ARMA)-based model estimator. It can meet application-level quality of service (QoS) goals while achieving high resource utilization. To evaluate the proposed controllers, simulations are performed on a testbed simulating a virtual data center using Xen virtual machines. Experimental results indicate that the controllers can improve CPU utilization and make the best tradeoff between resource utilization and performance for multi-tier web applications.     

基于反馈QoS量化的Web服务发现模型

服务发现是Web服务应用中极其重要的环节.随着Web服务数目的增长,提供相同功能的服务越来越多,现有的基于服务功能描述的服务发现机制越来越难以满足实际需求,于是向Web服务描述内部加入非功能性描述的成为Web服务应用的一个新研究方向.提出了一种基于反馈信息的QoS量化的Web服务发现和选择模型,采用了反馈机制对注册服务QoS进行量化,通过引入概念相近权重,实现了服务质量动态排序,满足了用户的个性化需求,提高服务的查准率.     

Towards an autonomic performance management approach for a cloud broker environment using a decomposition–coordination based methodology

Efficient resource allocation of computational resources to services is one of the predominant challenges in a cloud computing environment. Furthermore, the advent of cloud brokerage and federated cloud computing systems increases the complexity of cloud resource management. Cloud brokers are considered third party organizations that work as intermediaries between the service providers and the cloud providers. Cloud brokers rent different types of cloud resources from a number of cloud providers and sublet these resources to the requesting service providers. In this paper, an autonomic performance management approach is introduced that provides dynamic resource allocation capabilities for deploying a set of services over a federated cloud computing infrastructure by considering the availability as well as the demand of the cloud computing resources. A distributed control based approach is used for providing autonomic computing features to the proposed framework via a feedback-based control loop. This distributed control based approach is developed using one of the decomposition–coordination methodologies, named interaction balance, for interactive bidding of cloud computing resources. The primary goals of the proposed approach are to maintain the service level agreements, maximize the profit, and minimize the operating cost for the service providers and the cloud broker. The application of interaction balance methodology and prioritization of profit maximization for the cloud broker and the service providers during resource allocation are novel contributions of the proposed approach.     

网格资源发现模型的研究

提出了一种基于WSRF的网格资源发现模型,该模型采用三层架构以及集中式与分布式相结合的资源组织结构,将网格资源发现中的关键功能包装为有状态的Web服务.同时介绍了在该模型中资源加入与离开算法和资源查询算法.该模型结合WEB服务技术、P2P技术与网格资源管理技术的优点,并经试验测试分析与实际项目检验证明该模型能够适应大规模异构环境下的网格资源发现要求.     

A cloud computing platform for ERP applications

Cloud computing enables many applications of Web services and rekindles the interest of providing ERP services via the Internet. It has the potentials to reshape the way IT services are consumed. Recent research indicates that ERP delivered thru SaaS will outperform the traditional IT offers. However, distributing a service compared to distributing a product is more complicated because of the immateriality, the integration and the one-shot-principle referring to services. This paper defines a CloudERP platform on which enterprise customers can select web services and customize a unique ERP system to meet their specific needs. The CloudERP aims to provide enterprise users with the flexibility of renting an entire ERP service through multiple vendors. This paper also addresses the challenge of composing web services and proposes a web-based solution for automating the ERP service customization process. The proposed service composition method builds on the genetic algorithm concept and incorporates with knowledge of web services extracted from the web service platform with the rough set theory. A system prototype was built on the Google App Engine platform to verify the proposed composition process. Based on experimental results from running the prototype, the composition method works effectively and has great potential for supporting a fully functional CloudERP platform.     

A framework for QoS computation in web service and technology selection

There is a global trend of convergence of voice, video and data. Industry is facing a major shift from circuit-based voice networks to packet-based converged networks. In the last few years, data networks have been growing at much faster rate than voice networks, mainly due to the growth of Internet. As a result of this trend, more and more data are being sent over Data Networks (Voice over IP, Voice over Frame Relay, and Voice over ATM). The standards used are SOAD, WSDL, and UDDI. The emerging Service-Oriented Computing (SOC) paradigm promises to enable businesses and organizations to collaborate in an unprecedented way by means of standard web services. To support rapid and dynamic composition of services in this paradigm, web services that meet requesters' functional requirements must be able to be located from a large and constantly changing number of service providers based on their Quality of Service (QoS). In order to enable quality-driven web service selection, we need an open, secure and fair framework to evaluate the QoS of a vast number of web services. The fair computation and enforcing of web services should have minimal overhead but yet able to achieve sufficient trust by both service requesters and providers. In this paper I present our open and fair QoS computation model for web service selection.     

Consumer-centric QoS-aware selection of web services

There exist many web services which exhibit similar functional characteristics. It is imperative to provide service consumers with facilities for selecting required web services according to their non-functional characteristics or quality of service (QoS). However, the selection process is greatly complicated by the distinct views of service providers and consumers on the services QoS. For instance, they may have distinct views of the service reliability—wherein a consumer considers that a service is reliable if its success rate is higher than 99%, while a provider may consider its service as reliable if its success rate is higher than 90%. The aim of this paper is to resolve such conflicts and to ensure consensus on the QoS characteristics in the selection of web services. It proposes a QoS Consensus Moderation Approach (QCMA) in order to perform QoS consensus and to alleviate the differences on QoS characteristics in the selection of web services. The proposed approach is implemented as a prototype tool and is tested on a case study of a hotel booking web service. Experimental results show that the proposed approach greatly improves the service selection process in a dynamic and uncertain environment of web services.     

网格计算及网格体系结构研究综述

网格计算是继Internet和Web技术之后，信息技术的第3次革命，最终将改变分布式资源的共享和服务方式。对网格计算进行了简单介绍，重点介绍网格系统构建的核心技术，即网格体系结构的研究及最新进展情况。且着重介绍了以协议为中心的5层沙漏结构和以服务为中心的新一代网格体系结构OGSA。     

A user centric service-oriented modeling approach

With rapid development of service-oriented architecture and cloud computing, web services have been widely employed on the Internet. Quality of Service (QoS) is a very important criterion for service consumers to measure and select services. The selection of web services with respect to non-functional QoS criteria can be considered as a Multiple Criteria Decision Making (MCDM) problem when multiple consumers need to share a number of services. This paper describes a new user centric service-oriented modeling approach which is featured by integrating fuzzy Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) and Service Component Architecture (SCA) to facilitate web service selection and composition and to effectively satisfy a group of service consumers’ subjective requirements and preferences in the dynamic environment. The main contribution of this method is able to translate a group of users’ fuzzy requirements to services as well as model different levels of hardware and software as services to meet the requirements. We also design a simulated environment that includes 8*8 LED matrix on a circuit board that corresponds to an office with different appliances to demonstrate the dynamic service selection and binding. The simulation is used to assess the computational efficiency of the fuzzy TOPSIS method and the effectiveness of the proposed system.