排队理论在网络实时沟通服务系统的应用研究

网络实时沟通服务系统是一种集计算机软件技术、网络技术和排队理论于一体的综合信息系统,在当前的网络营销中已经得到了广泛应用。本文通过对网络实时沟通服务系统的服务的分析,建立了M/M/C/∞/∞排队系统的模型,并由此分析得到排队队长和等待时间等系统运行指标,最后确定出合理的客服数量,实现系统服务质量和效率的平衡。     

基于单总线数字传感器的温度控制系统原理及应用

随着现代化生产和科学研究的发展,人们对温度过程控制的要求越来越高。文章介绍以单片机P89C668为核心的智能温度控制系统。它使用一线制数字温度传感器DS18B20采集温度,与传统测温装置相比,具有结构简单,测温精度高、应用面广等特点。另外,系统还扩展了和上位计算机的串行通信,实现远程监控。整个系统不但成本低廉、而且使用和扩展方便,可广泛应用于人们日常生活、工农业生产和科学研究领域,为广泛深入应用提供了借鉴。     

用VB6.0实现计算机间串口通信

本文主要介绍利用VB6.0串行通信编程的方法,利用MSComm控件实现计算机与计算机间的串口通信。     

一种天馈线监测系统远程通信方法

天馈线监测系统与远端监控终端的通信在移动基站的维护保障工作中具有重要的意义,通过对该通信需求的研究,使用基于公共电话网采用调制解调器的数据传输方法,能够更好的实现通信功能。     

POS机软件升级的方法与设计

该文介绍了POS（Point of Sales,销售点终端）系统中软件升级的方法,从中选出一种方法作为软件升级的案例,从硬件的设计开始,一直到软件的设计,详细说明了如何进行软件升级。     

基于电池能源管理芯片Bq2060的SMBus总线编程

Bq2060作为一种智能电池能源管理芯片,广泛应用于笔记本电池管理系统中。它具有SMBus高效同步串行总线通讯接口功能,通过SMBus串行总线和系统进行通讯,可检测电池信息包括剩余容量、总容量、在现有放电速率下的剩余时间、充电电压等信息。介绍了基于Bq2060的SMBus串行接口的智能电池监测系统,利用SMBus接口和内嵌的智能电池状态监测系统进行实时检测,通过操作系统调用电池芯片内部指令进行智能控制,在分析其通讯协议的基础上,分析了SMBus总线编程配置和操作特点。     

Store-and-Forward Multicast Routing on the Mesh

We study the complexity of routing a set of messages with multiple destinations (multicast routing) on an n-node square mesh under the store-and-forward model. A standard argument proves that time is required to route n messages, where each message is generated by a distinct node and at most c messages are to be delivered to any individual node. The obvious approach of simply replicating each message into the appropriate number of unicast (single-destination) messages and routing these independently does not yield an optimal algorithm. We provide both randomized and deterministic algorithms for multicast routing, which use constant-size buffers at each node. The randomized algorithm attains optimal performance, while the deterministic algorithm is slower by a factor of O( log ² n). We also describe an optimal deterministic algorithm that, however, requires large buffers of size O(c). A preliminary version of this paper appeared in Proceedings of the 13th Annual ACM Symposium on Parallel Algorithms and Architectures, Crete, Greece, 2001. This work was supported, in part, by MIUR under project ALGO-NEXT.     

Deterministic secure quantum communication based on entanglement

Based on entanglement, a deterministic secure quantum communication protocol is proposed to distribute secret messages deterministically. In this scheme the messages are encoded in the particles of the Einstein-Podolsky-Rosen （EPR） pairs rotated random polarization angles by applying random and independent operations. Security analysis indicates that this scheme is secure against the present Trojan horse attack strategy and the impersonation attack strategy, and it can also ensure the security of the messages in a low noisy channel. Moreover, it has an advantage that communication can be launched by the sender just like an actual communication system.     

Distributed key management for dynamic groups in MANETs

Most existing solutions to group security in Mobile Ad Hoc Networks (MANETs) rely on a multicast Core Based Tree (CBT) for key distribution. Such solutions, although suitable for systems with low mobility and static characteristics, are unsuitable for dynamic and sparse groups with changing neighborhoods. In this paper, we propose an entirely decentralized key generation mechanism, employing a central trusted entity only during initialization. Using our approach, keys can be established between group members with absolutely no prior communication. The solution relies on threshold cryptography and introduces a novel concept of Node-Group-Key (NGK) mapping. We have provided an extensive analytical model for the computations involved and communication costs and have also provided a lie detection mechanism. Simulation results show appreciable performance improvement and enhanced robustness.     

基于椭圆曲线的数字签名方案研究

该文提出了一种新的基于椭圆曲线的数字签名方案。该数字签名方案的安全性是基于椭圆曲线离散对数难题上的。作者对该方案进行了安全性分析,发现该方案能有效防止伪造攻击。同时,该方案具有通信成本低、通信速度快、安全性高等特点,适合应用于小型身份认证系统。