计算机射频通信的实例与关键技术

射频通信技术极大地扩展了计算机的应用领域与灵活性,也对相关工程技术人员提出了新的要求。本文针对计算机射频通信的设计与实现,首先通过系统构成的实例,描述了此类系统基本的软硬件组成;然后,针对某些典型的关键技术问题,进行了深入分析,并给出了解决方法和建议。     

基于实时频谱分析的便携式射频通信干扰器设计

针对传统电子干扰器系统复杂、体积大、功耗高的缺点,文章设计了一种基于FXI规范的射频通信干扰器,FXI规范在FMC信号定义的基础之上,针对虚拟仪器领域的应用,定义了FXI模块的结构尺寸和FXI接口的专有信号组,提高了虚拟仪器模块的功能密度,从而实现了模块化、小型化和轻量化的设计目的。该射频通信干扰器内部同时集成了频谱仪模块和射频信号发生器模块,通过采用硬件逻辑实现射频信号的实时跟踪和干扰信号的实时合成,从而实现对高跳速射频通信信号的跟踪和干扰,用户可针对短波通信、超短波通信和微波通信扩展不同的模块,来实现在不同使用场景中的应用。经过测试,该射频通信干扰器的各项指标可满足使用要求,可进一步推广至电子对抗、无人机干扰等技术领域。     

应用于出租车稽查管理的RFID系统设计

针对出租车稽查管理设计产业化射频识别(RFID)系统,使用2.45 GHz有源RFID技术,硬件包括电子标签和微波识别器等,综合应用射频识别、无线通信、计算机通信技术以及数据库技术,实现对出租车的有效稽查和监控。实测结果表明,所设计的RFID系统的性能满足应用需求。     

基于微加速度计的AIR-MOUSE的研究

本文研究了一种基于微加速度计原理的空中鼠标.该鼠标采用微加速度计来检测手部运动的角度和速度等参数,并通过射频无线传输和USB接口实现与计算机的通信.本文介绍微加速度计、微控制器、无线射频模块、USB通讯等的集成研究,并对无线传输模块的软硬件做了详细阐述.     

基于通用计算机和USRP的LTE通信系统开发与实现

为了解决软件仿真不能进行真实信道环境下的性能演示、不能测量真实通信系统的传输速率与时延等方面的弊端,研究了基于通用计算机和通用软件无线电外设USRP的LTE通信系统的实现方法;对系统的基本结构与原理进行了分析;采用通用计算机与软件无线电前端相结合的方式,由通用计算机完成基带处理功能,由USRP完成基带信号的射频收发,并采用开放空中接口OAI平台作为软件架构实现数据处理与系统控制;在5 MHz系统带宽配置场景下,对所研究的LTE系统进行了软、硬件调试、测试与验证,实现了完整的LTE通信系统的功能;此外,进一步开发和实现了支持包括电脑终端和商用终端在内的多用户接入场景;测试结果表明所搭建的LTE通信系统能够与公共互联网实现互联互通,并维持较为稳定的连接.     

基于能量优化的射频识别标签防碰撞算法研究

射频识别标签防碰撞算法相关内容已经成为了物联网技术的一个重要的研究方向,以往的射频识别标签防碰撞算法的复杂度以及效率存在一些不足。提出一种基于功率控制的分组算法,以达到提高防碰撞算法性能以及节约能量的目标。采用功率控制相关技术使系统中的阅读器可以利用不同的发射功率来实现与不同距离的标签进行通信,每次在与阅读器通信时,只选定其中一定指定的区域进行通信,这样一来就可以实现阅读器与不同距离标签通信的功能。经实验测试实现了较好的节能效果,经实际应用满足了基于云平台和RFID实现闭环模式下智能表全寿命周期管理系统工程上的应用。     

数字频带通信系统计算机仿真

研究了使用计算机模拟数字频带通信系统各部分的基本原理算法,并画出图形,得到一些统计结论,以此来直观的研究通信系统的特性。研究了数字频带通信系统计算机仿真的实现方法。在研究了通信系统基本原理的基础上着重研究了使用MATLAB编程实现通信系统各部分算法的方法。并在此基础上编程开发出了一套完整的仿真系统。     

数字频带通信系统计算机仿真

研究了使用计算机模拟数字频带通信系统各部分的基本原理算法,并画出图形,得到一些统计结论,以此来直观的研究通信系统的特性。研究了数字频带通信系统计算机仿真的实现方法。在研究了通信系统基本原理的基础上着重研究了使用MATLAB编程实现通信系统各部分算法的方法。并在此基础上编程开发出了一套完整的仿真系统。     

单片机的选择和串行通信协议的设计

目前,射频识别技术（RFID）在国外发展非常迅速,该技术被广泛应用于工业自动化、商业自动化、交通监控、高速公路自动收费系统、停车场管理系统等领域。将远距离射频识别技术与无线通信技术、单片机控制技术、计算机串口通信技术结合在一起,为实现体育赛事中径赛记圈自动化提出了系统解决方案。首次将无线通信技术应用于径赛记圈工作中,制定了适合运动场地内信号传送的小型通信网络,并编制了通信协议。该项目的研究可以实现径赛记圈工作的自动化,提高记圈的准确性,因此,该项目的研究切实可行,且应用前景巨大。     

基于硬件协议栈的网络化射频标签识别系统

随着射频识别系统的应用领域的不断推广，对于射频识别系统的应用而言，主控制平台(上位机)与射频识别系统的通信方式通常采用传统的RS232串行通信或工业总线形式。这些方式往往有部署性和通用性的缺陷。为了进一步扩展射频识别系统的应用，论文提出了采用通用网络接口的高频射频识别系统，实现了射频识别、网络通信接口、存储器管理和时钟控制等功能，使射频识别系统可以作为互联网上的一个节点来实现远程控制和数据下载。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

正~~     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate