A study on numerical solution method for efficient dynamic analysis of constrained multibody systems

A new and efficient computational method for constrained multibody systems is proposed. In the proposed method, local parametrization method is employed to apply the same solution method for position, velocity, and acceleration analyses since the coefficient matrices for each analysis have an identical matrix pattern. The skyline solution method is used to overcome numerical inefficiency when solving large scaled equations. Also, subsystem mpartitioning method is derived systematically to perform parallel processing for real time simulation. To show the numerical accuracy and efficiency of the proposed method, three numerical problems are solved.     

下一代网络NGN技术探析

介绍了NGN网络的概念、基本特征、优势和关键技术，其中关键技术包括软交换技术和IMS，围绕NGN体系结构讨论了NGN网络所必须解决的技术条件和环境因素，还从功能特征和通信属性2个方面介绍了NGN应用业务分类．     

ERP中人力资源子系统解决方案研究与实现

论述ERP(EnterpriseResourcePlan)环境下人力资源管理系统与其它系统的联系、系统体系结构、系统开发实现技术。重点阐述客户 服务器开发中的一些具体实现技术     

Critical Issues for QoS Management and Provisioning in the IP Multimedia Subsystem

This paper presents state-of-the-art research efforts in implementing a Policy Based architecture for Quality of Service management and provisioning of network services in the IP Multimedia Subsystem (IMS). While Policy Based Network Management has been adopted by the Third Generation Partnership Project and the Telecoms & Internet converged Services & Protocols for Advanced Networks as the solution for managing QoS in the IMS, the proposed mechanisms are sorely lacking in many aspects. First, the policy logic and decision mechanism are not specified, nor is the actual resource allocation procedure. Second, while the IMS is being tailored as the Service Delivery Platform for Next Generation Networks many of the QoS provisioning solutions are designed specifically for UMTS as an access network and need to be enhanced to support other technologies. In the current specifications, 3GPP is already evolving to support Packet Cable, WLAN and WiMAX accesses, but their respective policy-related sections are still void. Furthermore the proposed solutions do not specify how the network processes user requests for services in the IMS infrastructure. This article analyses critical QoS management issues within the IMS, and proposes solutions by designing a Policy Decision Function, which is the central element in the policy architecture. These solutions are presented in a proof of concept implementation running in a real IMS testbed making use of the Open Source IMS Core and considering the management of QoS in different scenarios.

一种新的基于IMS的SIP重传机制

目前,IP多媒体子系统（IMS）中基于会话初始化协议（SIP）的会话建立时间受到无线信道约束带宽、帧错误率（FER）值的影响,交换的消息数量、消息长度以及重传机制对于会话建立的时延有很大的影响,延长了会话建立的时间。将基于SIP的会话建立与无线信道的性能结合,提出一种新的SIP自适应重传机制。实验结果表明,该重传机制缩短了会话建立的时间,对IMS端到端的服务质量（QoS）性能有明显的改善。     

轻型无人机飞行控制系统适航安全性研究

随着技术的发展,起飞飞全重25公斤至150公斤的轻型无人机飞行空域可完全融入民航空域,本文试着从适航审定角度讨论其适航安全性。采用民机事故概率统计结果与适航安全水平对比方法,确定了该型无人机系统定量化的期望安全水平。然后以最关键的飞控分系统为对象,在某型无人机上进行了飞行控制功能危险分析和故障模式影响分析,获得飞控分系统安全关键清单。最后基于SAE ARP4754A和RPAS 1309,对飞控分系统部件的期望安全水平进行了定量化规定,和研制保证等级的分配。研究结果对全重25公斤至150公斤轻型无人机的适航审定管理实践有参考借鉴意义。     

一种基于IMS的BitTorrent文件分布系统架构

随着移动通信网络的迅速发展,在移动网络中提供P2P服务,特别是BitTorrent(BT)文件共享系统的需求日益突出。该文从BT协议的特点及3G网络的实际情况出发,分析扩展eDunkey体系、移动代理服务器等方式的不足,提出一种基于IMS的BT文件分布系统架构,研究了系统的工作机制和各组成部分的功能,解决了网络结构复杂、成本高、不易推广等问题。     

传统固定网络优化及演进研究

研究了当前固定语音网通过网络瘦身来实现网络优化的思路和方案,并讨论了固定语音网向IMS演进的策略和步骤。     

Performance analysis of advanced I/O architectures for PC-based video servers

In the personal computing and workstation environments, more and more I/O adapters are becoming complete functional subsystems that are intelligent enough to handle I/O operations on their own without much intervention from the host processor. The IBM subsystem control block (SCB) architecture has been defined to enhance the potential of these intelligent adapters by defining services and conventions that deliver command information and data to and from the adapters. In recent years, a new storage architecture, the redundant array of independent disks (RAID), has been quickly gaining acceptance in the world of computing. In this paper, we discuss and present a performance analysis of the SCB architecture and disk array technology in typical video server environments. In particular, we would like to see whether a disk array can outperform a group of disks (of the same type, the same data capacity, and same cost) operating independently (not in parallel as in a disk array) in a video server environment where most disk I/O operations are large sequential reads.     

DCS系统实际运行中的结构设计改进

本文论述了DCS控制器子系统的电源系统结构设计与软件设计的改进以及检修方法的改进等。