基于DMT的1553B带宽扩展研究

由于传统的MIL-STD-1553B总线难以满足高速数据传输需求且更换现有总线代价过高,因此迫切需要在不影响现有基带通信的条件下升级1553B系统以提供高速通信接口。本文分析1553B的信道特性并据此选择频谱利用率高、抗频率选择性衰落的离散多音调制(DMT)作为扩展带宽的技术,基于离散多音调制,提出一个与现有通信相互兼容的扩展方案以显著提高传输速率,并对该方案涉及的关键技术进行介绍。     

Excel二次开发在模拟水氡观测中的应用

尝试对Excel工作表进行二次开发,将其应用到台站模拟水氡观测工作当中,可以自动计算出模拟水氡观测的标定、季检结果,需要作图的还可以自动作图,杜绝了人工计算产生的不必要误差,减轻了劳动强度,实现了观测资料的数字化存档,对台站模拟水氡观测日常工作具有很大帮助。经吉林省地震局多个台站使用,Excel工作表自动计算结果与人工计算结果两者完全相符,效果良好。     

计算机网络技术的发展现状和趋势分析

文章首先概述了计算机网络发展的历程与现状,并分析当今计算机网络发展中存在的一些问题,然后对计算机网络的发展趋势及策略进行总结分析,为当今计算机网络的良性发展出谋划策。     

煤炭企业信息化建设问题探讨

企业信息化作为国民经济信息化的基础,是当前推进国民经济信息化的重中之重。伴随全球信息化浪潮,我国煤矿企业信息化进程不断向深度和广度双向推进,但依然存在一些不尽人意的地方。本文首先分析了煤矿企业信息化的现状和制约信息化的原因,在此基础生展望了煤矿企业信息化的发展方向。     

军用ASIC对策的探索与思考

本文从军用ASIC的技术基础,需求牵引和效益目标出发,论述了军用ASIC的发展模式和对策。建立军用Foundry,在通用CAD基础上实现军用ASIC的CAD工具是必要的。门阵列和标准单元是两种主要方法。从全定制向单元库过渡,是发展军用模拟ASIC和A/D ASIC的可行方案。努力发展整机-元器件垂直集成,提高ASIC的“自用率”,有利于促进军民结合。     

嵌入式调试中的数据获取和错误定位

嵌入式软件系统因其软件相关性和硬件相关性而比常规软件的调试复杂很多,特别是在数据获取和故障定位方面最为突出。从嵌入式软件开发与常规软件开发的异同着手,以该行业实践积累为基础,列出并讨论了一些行之有效的数据获取及错误定位方法,希望能为该领域开发人员提供一点帮助。     

数字证书在环保行业的应用分析

目前国家环保部正在开展的国家环境信息与统计能力建设项目中,采用数字证书为业务系统提供强身份认证服务。详细论述了数字证书在环保部的应用模式,指出了今后的工作方向,同时也指出了现有应用模式的不足之处。     

Robust stability and stabilization of discrete singular systems with interval time-varying delay and linear fractional uncertainty

The robust stability and robust stabilization problems for discrete singular systems with interval time-varying delay and linear fractional uncertainty are discussed. A new delay-dependent criterion is established for the nominal discrete singular delay systems to be regular, causal and stable by employing the linear matrix inequality (LMI) approach. It is shown that the newly proposed criterion can provide less conservative results than some existing ones. Then, with this criterion, the problems of robust stability and robust stabilization for uncertain discrete singular delay systems are solved, and the delay-dependent LMI conditions are obtained. Finally, numerical examples are given to illustrate the e?ectiveness of the proposed approach.     

Handling multiple objectives with biogeography-based optimization

Biogeography-based optimization (BBO) is a new evolutionary optimization method inspired by biogeography. In this paper, BBO is extended to a multi-objective optimization, and a biogeography-based multi-objective optimization (BBMO) is introduced, which uses the cluster attribute of islands to naturally decompose the problem. The proposed algorithm makes use of nondominated sorting approach to improve the convergence ability effciently. It also combines the crowding distance to guarantee the diversity of Pareto optimal solutions. We compare the BBMO with two representative state-of-the-art evolutionary multi-objective optimization methods, non-dominated sorting genetic algorithm-II (NSGA-II) and archive-based micro genetic algorithm (AMGA) in terms of three metrics. Simulation results indicate that in most cases, the proposed BBMO is able to find much better spread of solutions and converge faster to true Pareto optimal fronts than NSGA-II and AMGA do.     

Design of robotic visual servo control based on neural network and genetic algorithm

A new visual servo control scheme for a robotic manipulator is presented in this paper, where a back propagation (BP) neural network is used to make a direct transition from image feature to joint angles without requiring robot kinematics and camera calibration. To speed up the convergence and avoid local minimum of the neural network, this paper uses a genetic algorithm to find the optimal initial weights and thresholds and then uses the BP algorithm to train the neural network according to the data given. The proposed method can effectively combine the good global searching ability of genetic algorithms with the accurate local searching feature of BP neural network. The Simulink model for PUMA560 robot visual servo system based on the improved BP neural network is built with the Robotics Toolbox of Matlab. The simulation results indicate that the proposed method can accelerate convergence of the image errors and provide a simple and effective way of robot control.