基于Web服务的局数据管理系统

由于移动通信网络的不断扩容和业务的不断扩展,网络上网元的类型和数量都在不断增加,这就对局数据的管理提出了更高的要求。如果采用Web服务技术和用正则表达式来描述数据解析规则的方法,设计出来的局数据管理系统可以通过简单的配置来动态地将新增的网元添加到系统中,并能够以通用的接口提供解析与核查服务。通过实际运行证明,该系统具有通用性、可扩展性和较高的效率,能够保障移动网络的稳定运行。     

Adaptive searching and replication of images in mobile hierarchical peer-to-peer networks

Due to the limitation of resources in mobile handheld devices and bandwidth constraints in wireless networks, it is important to efficiently manage image content and traffic to improve network throughput and response time. The efficient distribution of images in wireless networks is based on many parameters like the quality of service requirement, available bandwidth, restricted memory and diverse user profiles. We consider digital images as data objects accessed in a hierarchical mobile ad-hoc peer-to-peer network, referred as M-P2P. Our objective is to optimize the number of replicas of images in such a network architecture based on the resource limitations of the requesting peers equipped with miniature mobile devices as well as of wireless constraints in mobile ad-hoc networks (MANET). While replicating images, fragments of different resolution and their residues are used to optimize the traffic in the network and to decrease the search turnaround time. We call this replication algorithm as Ada-Rep. Performance evaluation is done by simulating Ada-Rep, base replication and uniform replication methods to evaluate parameters such as response time, failure rate, memory usage, traffic etc. Our results prove the efficiency and better performance of Ada-Rep.     

移动计算中基于Mobile Agent的Web Services订阅调用模型

在分析了移动环境的特点以及传统J2ME应用程序Web Services调用的问题之后,针对传统移动环境下调用Web Ser-vices存在的问题,提出了基于Mobile Agent并结合订阅的Web Services调用模型,讨论了该模型的原理以及方法,提出了简单消息通信模式,代理服务器和订阅机制以及移动代理迁移策略.最后,结合该改进模型在中石化胜利油田中的实际应用,总结了它适用于移动环境的几个特点,比较了改进模型与传统模型调用Web Services的效率,表明了其正确性和适用性.     

基于Web Services的语义异构数据集成设计与实现

高校在信息化建设过程中积累了大量异构、异质的数据源,如何将这些异构数据源中相关的数据资源进行有效整合是当前急需解决的问题.为此,提出了一种新的基于Web Services的异构数据集成解决方案,利用Web Services技术在异构数据集成中的优势,采用虚拟数据库法设计思想,通过设计领域字典表及字段映射表,有效地解决了异构数据集成中最难解决的语义异构问题,并从数据模型转换、全局查询等方面阐述了该方案的可行性.实验结果表明,该方案具有可用性和高效性.     

Web Services在构建企业信息化平台中的应用研究

企业信息化建设一直是企业比较关心的课题之一,但是随着网络技术和通信技术的飞速发展,在企业内部或不同企业间如何实现信息共享和数据集成,成为构建企业信息化平台中所必须解决的关键问题。讨论了Web Services的基本概念和体系架构,根据Web Services与企业信息化的特点,提出了利用Web Services构建企业信息化平台,并结合企业实际运营中的相关服务,给出了Web Services在构建企业信息化平台中的具体应用。     

基于Web Services XML-RPC的医院HIS/RIS集成研究与实现

医院不同信息系统的集成是医学信息学的一个难点,而Web Services被业界称为是计算机IT技术的第3次革命,它为异构系统的信息交互提供了一个参考模型.参照Web Services体系架构模型,对HIS/RIS集成的信息流程以及工作环境进行了分析研究,最终利用Web Services XML-RPC技术设计并实现了医院HIS/RIS的无缝连接与集成.     

Dynamic fuzzy logic and reinforcement learning for adaptive energy efficient routing in mobile ad-hoc networks

In this paper, a dynamic fuzzy energy state based AODV (DFES-AODV) routing protocol for Mobile Ad-hoc NETworks (MANETs) is presented. In DFES-AODV route discovery phase, each node uses a Mamdani fuzzy logic system (FLS) to decide its Route REQuests (RREQs) forwarding probability. The FLS inputs are residual battery level and energy drain rate of mobile node. Unlike previous related-works, membership function of residual energy input is made dynamic. Also, a zero-order Takagi Sugeno FLS with the same inputs is used as a means of generalization for state-space in SARSA-AODV a reinforcement learning based energy-aware routing protocol. The simulation study confirms that using a dynamic fuzzy system ensures more energy efficiency in comparison to its static counterpart. Moreover, DFES-AODV exhibits similar performance to SARSA-AODV and its fuzzy extension FSARSA-AODV. Therefore, the use of dynamic fuzzy logic for adaptive routing in MANETs is recommended.     

A high performance backoff protocol for fast execution of composite web services

Using web services to expose applications over the Internet is now a widely accepted practice. Currently, there are several ongoing efforts that provide ways to effectively compose web services distributed across different organizations. One of the problems underlying the deployment of such composite services on the web, however, is service co-allocation that arises when a composite service needs to ensure all the required component services to be available for execution at the same time. Motivated by this, this paper presents a new decentralized protocol, named web service co-allocation protocol (WSCP), which can facilitate fast execution of composite web services. The proposed framework is an enhancement of the famous two phase commit protocol through the incorporation of tentative hold phase as well as the employment of a new high performance backoff protocol developed to better address the dynamics of the service co-allocation problem. The simulation results show that the proposed approach yields significant improvements over existing protocols.     

A distributed-request-based CDMA CAC for DiffServ multimedia services in wireless cellular mobile networks

In this paper, a distributed-request-based CDMA DiffServ (differentiated service) call admission control (CAC) scheme is proposed to provide various multimedia services seamlessly in wireless mobile Internet. Conventional CDMA CAC schemes cannot fully support DiffServ QoS (Quality of Service) and seamless handoff due to lack of consideration on service priority and seamless mobility. Therefore, in order to achieve QoS guarantee for each service class, seamless fast-handoff, and high utilization of the scarce wireless resource, we define a code assignment policy and an adaptive access permission scheme taking each user’s service priority and mobility into consideration. For that purpose, in the proposed scheme, the DQRUMA/CDMA is combined with the new code assignment scheme and the adaptive access permission probability (APP). Numerical examples show that the forced termination ratio of handoff calls is guaranteed to be much less than the blocking ratio of new calls for a seamless fast-handoff while proposed scheme provides QoS guarantee for each service class efficiently.