基于FPGA的双路高速数据采集系统的设计

以脉冲激光测距为应用背景,设计了1种双路1 Gsps采样率的高速数据采集系统的设计方案,该系统以EP2S60系列的FPGA为核心控制模块,ADC08D1000为模数转换芯片测量I、Q两路脉冲信号时间间隔.FPGA的资源分布决定ADC输出的两路信号(I、Q)需由FPGA的两侧共4个BANK接收,由此会造成系统测量的固定误...     

新型简易单相五级逆变器

探讨了将中点箝位三级逆变器的一桥臂用于单相逆变桥,来作简易单相五级逆变器用,改善输出电压波形。其特点是元器件用量少、成本低、可靠性高。经Matlab/simulink仿真实验证明,设计方案是可行的。     

葡聚烯糖0.5%可溶粉剂防治番茄病毒病试验

进行了葡聚烯糖0.5%可溶粉剂防治番茄病毒病的田间试验。结果表明,该剂能够很好地控制番茄病毒病,防治效果明显高于对照,且对作物安全。     

H.264/AVC中SP帧技术的应用研究

SP帧技术是H.264/AVC新视频标准中定义的新类型帧技术。其主要特点是:即使使用不同的参考帧也能预测恢复出相同的SP帧,因而SP帧可以在流间切换、拼接、随机插入以及差错控制等应用中取代I帧实现相应功能。文章在介绍基于SP帧技术各种具体应用的基础上,通过大量仿真试验对SP帧进行了各种情况下的研究,并从中获得具有指导性的结论。     

基于P2SP技术的数字图书馆原型设计

扼要介绍数字图书馆目前发展概况以及P2SP技术在国内外数字图书馆的发展情况,在简要分析P2SP技术的技术特点的基础上提出基于P2SP技术的数字图书馆原型设计。     

小灵通短信SP接入技术在电信业务支撑系统中的应用

短信技术除了在人们日常的信息交流外,还可以在企业生产管理中得到广泛的应用。本文就SMGP协议、SP接入技术以及它们在电信业务支撑系统中的实现方法做详细说明。     

短消息服务提供商系统的研究与实现

短信服务（SMS）在通信产业中正在占据越来越重要的位置。文章介绍了中国网通SMS短信服务提供商（SP）与中国网通短信中心（SMSC）以及用户手机终端之间的数据交互原理，给出了SP提供商的短信增值业务运营平台的设计原理及实现方法。该平台已投入使用，并取得了良好的效果。     

ZigBee技术在远程抄表系统中的应用

将无线射频芯片与单片机系统相结合,可以实现无线远程水表控制和对流量数据的读取,该系统通过射频收发模块实现数据的传输。本文重点介绍以Freescale公司生产的MC9S08GB60单片机和MC13192射频收发模块为核心的远程抄表系统的硬件电路以及软件流程设计。     

Income, Time Effects and Direct Preferences in a Multimodal Choice Context: Application of Mixed RP/SP Models with Non-Linear Utilities

Transport problems typically involve at least two types of constraints, on income and on time. Therefore, the indirect utility function depends either on the income available after having subtracted the cost of the discrete alternative and on the free time left after having worked and travelled by each competing option. In the typical linear-in-the-attributes and in-the-parameters specification, that represents the first grade approximation of the indirect utility function, the effect of income and time constraints cancel out and only the cost and time of the alternatives matter in the comparison between them. From a microeconomic point of view this is equivalent to assume that income and time effects could be disregarded; which is not always the case. To account for these effects the utility function should include second order attributes; however, in non-linear utility functions it may not be easy to distinguish among several effects that could be relevant: direct preferences for good and leisure, and simple interactions between attributes other than income and time effects. This paper analyses these effects from a theoretical point of view focusing on the possible confounding problem in detecting income and time effects. We use a dataset collected for a modal choice context and containing both revealed and stated preference data, and estimate several NL models examining the effect of the different second-order terms on detecting income and time effects. We compared specifications including square cost and time attributes, interactions between time and cost, cost divided by the income available to be spent on free time, and time multiplied by free time. Our results confirm the strong effect of direct preferences for goods and leisure time on choice, and the potential confounding effect between quadratic attributes and other non-linear omitted terms. Finally, we also found that care should be taken in highlighting income and time effects using mixed data sources, since confounding effects can occur when non-linearities are accounted for in both data sets.