电子天平示值误差测量结果的不确定度评定

一切测量结果都不可避免地具有不确定度，结合实际应用的情况，详细介绍了电子天平示值误差测量结果的不确定度评定方法。     

探地雷达在地下管线探测中的应用

探地雷达技术是如今适应快速、准确、无损地探测地下障碍物而迅速发展的电磁技术。文中介绍了探地雷达的工作原理及工作方式，并通过结合工程实例来探讨探地雷达在地下管线探测中的广泛应用。     

Analysis of Distributed DDQ for QoS Router

In a packet switching network, congestion is unavoidable and affects the quality of real‐time traffic with such problems as delay and packet loss. Packet fair queuing (PFQ) algorithms are well‐known solutions for quality‐of‐service (QoS) guarantee by packet scheduling. Our approach is different from previous algorithms in that it uses hardware time achieved by sampling a counter triggered by a periodic clock signal. This clock signal can be provided to all the modules of a routing system to get synchronization. In this architecture, a variant of the PFQ algorithm, called digitized delay queuing (DDQ), can be distributed on many line interface modules. We derive the delay bounds in a single processor system and in a distributed architecture. The definition of traffic contribution improves the simplicity of the mathematical models. The effect of different time between modules in a distributed architecture is the key idea for understanding the delay behavior of a routing system. The number of bins required for the DDQ algorithm is also derived to make the system configuration clear. The analytical models developed in this paper form the basis of improvement and application to a combined input and output queuing (CIOQ) router architecture for a higher speed QoS network.     

结构振动试验转接器的设计及安装问题

一些产品及其相关部件在作振动试验时，由于产品的外形或特殊要求不能直接安装在振动台面上，需要通过特别设计的转接器（夹具）来进行连接，这种夹具实际上是一种附加结构，它作为台面与试件之间的中介，如设置不当将影响振动试验结果的可靠性。本文通过对某事例的分析与研究，从试验频带、允许误差、跟随条件以及安装共振频率等方面阐明与讨论了相关夹具的特性、设计原则与安装等问题。     

几种涉密网主机系统保护及审计技术的比较

论文比较详细地阐述了涉密网主机系统所面临的安全隐患,提出了涉密网主机安全防护所要解决的几个技术问题,并就可能实现的技术方法进行了探讨和比较。     

Efficient multicast search under delay and bandwidth constraints

The issue of a multicast search for a group of users is discussed in this study. Given the condition that the search is over only after all the users in the group are found, this problem is called the Conference Call Search (CCS) problem. The goal is to design efficient CCS strategies under delay and bandwidth constraints. While the problem of tracking a single user has been addressed by many studies, to the best of our knowledge, this study is one of the first attempts to reduce the search cost for multiple users. Moreover, as oppose to the single user tracking, for which one can always reduce the expected search delay by increasing the expected search cost, for a multicast search the dependency between the delay and the search cost is more complicated, as demonstrated in this study. We identify the key factors affecting the search efficiency, and the dependency between them and the search delay. Our analysis shows that under tight bandwidth constraints, the CCS problem is NP-hard. We therefore propose a search method that is not optimal, but has a low computational complexity. In addition, the proposed strategy yields a low search delay as well as a low search cost. The performance of the proposed search strategy is superior to the implementation of an optimal single user search on a group of users. Amotz Bar-Noy received the B.Sc. degree in 1981 in Mathematics and Computer Science and the Ph.D. degree in 1987 in Computer Science, both from the Hebrew University, Israel. From October 1987 to September 1989 he was a post-doc fellow in Stanford University, California. From October 1989 to August 1996 he was a Research Staff Member with IBM T. J. Watson Research Center, New York. From February 1995 to September 2001 he was an associate Professor with the Electrical Engineering-Systems department of Tel Aviv University, Israel. From September 1999 to December 2001 he was with AT research labs in New Jersey. Since February 2002 he is a Professor with the Computer and Information Science Department of Brooklyn College - CUNY, Brooklyn New York. Zohar Naor received the Ph.D. degree in Computer Science from Tel Aviv University, Tel Aviv, Israel, in 2000. Since 2003 he is with the University of Haifa, Israel. His areas of interests include wireless networks, resource management of computer networks, mobility, search strategies, and multiple access protocols.     

基于击键动力学和口令的双因素用户验证

提出基于击键动力学和口令的一种新的身份验证方法，该方法监视用户在输入口令时的用户击键特征的有关数据，通过采用监视键盘输入时一种新的三键持续时间的击键特征表示，用一种表示用户节奏的相对击键速度的距离衡量方式，在正常样本上建立用户模式，然后用新样本与用户模式的距离匹配情况来验证用户身份的合法性。实验表明该方法简单实用，识别效率高。     

浅谈亚欧海底光缆S2段远供电源(PFE)及其维护管理

以亚欧海底光缆S2段为例,介绍亚欧海底光缆远供电源(PFE)的供电方式,以及其在正常运行时和故障维修时的维护管理方法。探讨在实际维护中如何贯彻落实及灵活运用系统联合维护文档,总结适合中国国情的远供电源维护经验,确保亚欧海底光缆远供电源安全稳定运行。     

一般阵列误差情况下信号二维方向角估计

针对均匀圆阵存在一般阵列误差的情况,提出一种信号二维方向角估计方法.基于均匀圆阵的阵列流形和阵列输出的协方差矩阵,采用加权总体最小二乘法估计信号二维方向角.并给出了解整周期性模糊的方法.计算机仿真表明了此方法估计精度高,对阵列误差鲁棒性强,并且各项性能都接近于CRB.     

国产风机盘管空调系统常见问题分析

分析了国产风机盘管使用中常见的问题,指出机组因风量不足、冷量风量匹配不合理以及风机盘管某些设备故障,导致了风机盘管精度低、舒适性差、能耗高等一系列问题。指出应引起空调设计和运行维护人员的注意。