新媒体广播服务器的设计与实现

随着互联网技术的发展,传统的广播电台行业受网络媒体的影响越来越大。通过对广播行业的调查研究发现,传统广播正向新媒体广播开始转变。针对现有的流媒体服务器不具有多种音频源自动切换,控制功能薄弱,播放延迟大等问题,设计并实现了一个符合新媒体要求的新媒体广播服务器。介绍了流媒体音频服务器的应用及研究现状,阐述了广播行业对新媒体广播服务器的具体要求,描述了新媒体广播服务器的功能,详细分析了环形缓冲线程同步模型、音频源自动切换方法,远程控制方法。最后通过实验测试了服务器的功能和性能,验证了新媒体服务器已满足新媒体广播需求,达到了商用目的。     

基于Client/Server架构的公路养护成本管理系统

由于现今计算机技术、信息技术和网络技术发展势头的迅猛,在推动和实现管理体制的改进、技术上的创新和加强管理单位核心竞争力的方面上,信息化已经成为了其中的一个重要技术措施和必由之路。因此充分利用现代化的计算机技术,研究开发出相应的计算机管理系统,方便、准确、快捷的为养护工程预算提供科学的手段,将有助于提高养护管理水平。对一个基于 Client/Server 的公路成本管理系统的设计进行了研究,并探讨了这种系统在当下的应用优势和技术开发方法。     

企业级服务器虚拟化性能评估方法

随着计算机硬件性能及虚拟化技术的快速发展,越来越多的企业通过采用服务器虚拟化技术来降低信息中心机房的整合成本,提高硬件利用率。然而,在如何选择最佳的服务器硬件搭建高性能、低成本的虚拟化平台,尤其是在虚拟化应用层面上的性能评估是目前亟需解决的问题之一。介绍了四种服务器虚拟化的性能评估方法,分析比较了不同评估方法的特点和局限及其适用环境,为企业信息中心机房如何更好地去部署实施服务器虚拟化提供建设思路。     

银行管理信息系统服务器国产化过程中的ETL应用迁移

本文对某国有大型银行省级分行将ETL应用系统由访问进口服务器迁移至国产高端容错计算机环境的过程进行了描述. 通过基于应用域的数据拆分和基于视图/物化视图、数据同步、同义词的数据同步, 基本完成了分行应用数据从进口服务器环境往国产高端容错计算机环境的迁移过程. 在这个过程中, 我们发现由于客观条件的限制, 数据同步前后数据的一致性结果比较存在一定难度, 对应用迁移正确性的确认造成不利影响. 在实际的迁移过程中, 通过相应的措施保证, 顺利完成了迁移过程.     

联合科学数据中心的在线水文模型服务研究

在线水文或陆面过程模型服务可以为广泛的网络用户提供数据分析、预报预警和决策支持等功能。随着科学数据共享环境发展的日趋成熟,如何便捷地利用丰富的在线数据资源成为在线模型的新挑战。当前的在线模型服务研究对于复杂多样的模型数据和参数需求的标准化不足,且缺少与科学数据中心的紧密协作。建立了一个模型服务器、数据服务器、客户端三方紧密协作的在线模型服务方案。结合一般性工作流程,基于标准化的服务接口来构建在线的水文和陆面过程模型和数据服务,重点介绍了在线服务架构、主要接口及实现的关键技术,包括模型数据和参数的传递和格式转换、数据服务器数据查询的实现和模拟结果的返回。这套方案充分利用了模型服务器的计算优势和科学数据中心的资源,可以被复制和扩展到其他类似应用。     

嵌入式Web服务器的交通信号机控制系统设计

传统交通信号机配置软件一般采用C/S架构,需要专用软件通过PC机网口或串口等设备与其相连进行配置。为避免在路口实际操作中的不便,设计了一种应用嵌入式Web服务器搭建的B/S架构的交通信号机配置方案。重点介绍Mongoose服务器的搭建、CGI技术的工作原理以及CGI程序的实现。测试结果表明,基于B/S架构的配置软件在控制的快速性、监控的实时性以及系统的稳定性方面都达到了系统要求。     

基于ASOPCDA.DLL动态链接库的OPC服务器开发应用

针对现有煤炭自动化控制系统使用的通信协议种类多,存在数据转换、集成难等问题,开发了一种基于ASOPCDA.DLL动态链接库的OPC服务器,详细介绍了该服务器的开发流程及其在选煤厂中的应用.该服务器可将各种不同的通信协议转换为OPC通信协议,方便上层软件对下层设备的数据集成与整合,为实现信息化提供通信协议基础支撑.     

Performance analysis of the internet‐protocol multimedia‐subsystem's control layer using a detailed queueing Petri‐net model

In the current trend in telecommunications industry towards all‐internet‐protocol (IP) infrastructures, IP multimedia subsystem (IMS) plays a critical role by providing a coherent data and control‐plane solution for large‐scale live multimedia applications in a flexible and cost‐effective manner. On the other hand, such a large‐scale service platform would inevitably fail without effective support for the quality‐of‐service (QoS) requirements perceived by its users. Among the most important factors that influence user QoS are system performance and scalability. In this paper, a performance model for IMS systems is developed using the queueing Petri nets (QPNs) as the modeling formalism. The model's parameters are tuned based on the measurements carried out using a well‐known IMS implementation. The model is validated against the real system. During the model calibration, the Java garbage‐collector process used in the home subscriber‐server (HSS) implementation was found to be a main factor in the discrepancy between the model and the reality. In addition, the effects of other factors such as the network stack in the operating system are investigated. The validated model is employed to give insights into the scalability of every single instance of IMS implementation. The model is extended to study load balancing among multiple instances of HSS to remove the main bottleneck in the system. It provides a valuable platform for resource management of various components of the IMS ecosystem to support the intended level of QoS for the users.     

Secure user authentication scheme with novel server mutual verification for multiserver environments

The fast growth of mobile services and devices has made the conventional single‐server architecture ineffective from the point of its functional requirements. To extend the scalability and availability of mobile services to various applications, it is required to deploy multiserver architecture. In 2016, Moon et al insisted that Lu et al's scheme is weak to insiders and impersonation attack, then they proposed a biometric‐based scheme for authentication and key agreement of users in multiserver environments. Unfortunately, we analyze Moon et al's scheme and demonstrate that their scheme does not withstand various attacks from a malicious registered server. We propose a user authentication scheme with server mutual verification to overcome these security drawbacks. The proposed scheme withstands an attack from malicious insiders in multiserver environments. We use a threshold cryptography to strengthen the process of server authorization and to provide better security functionalities. We then prove the authentication and session key of the proposed scheme using Burrows‐Abadi‐Needham (BAN) logic and show that our proposed scheme is secure against various attacks.     

Multiobjective virtual machine placement mechanisms using nature‐inspired metaheuristic algorithms in cloud environments: A comprehensive review

Cloud computing introduced a new paradigm in IT industry by providing on‐demand, elastic, ubiquitous computing resources for users. In a virtualized cloud data center, there are a large number of physical machines (PMs) hosting different types of virtual machines (VMs). Unfortunately, the cloud data centers do not fully utilize their computing resources and cause a considerable amount of energy waste that has a great operational cost and dramatic impact on the environment. Server consolidation is one of the techniques that provide efficient use of physical resources by reducing the number of active servers. Since VM placement plays an important role in server consolidation, one of the main challenges in cloud data centers is an efficient mapping of VMs to PMs. Multiobjective VM placement is generating considerable interest among researchers and academia. This paper aims to represent a detailed review of the recent state‐of‐the‐art multiobjective VM placement mechanisms using nature‐inspired metaheuristic algorithms in cloud environments. Also, it gives special attention to the parameters and approaches used for placing VMs into PMs. In the end, we will discuss and explore further works that can be done in this area of research.