基于I/Q正交双路的USB、LSB和DSB的一种识别算法

针对传统的单路P参数识别算法中必须保留载波残余频偏的缺点,提出了一种基于I/Q正交双路的识别算法.该算法直接将信号搬到基带,无需保留载波残余频偏,消除了残余频偏对较低频段信号识别和解调的不利影响.给出了上边带调制信号、下边带调制信号和双边带调制信号在不同信噪比(SNR)下的P参数值,并给出了其在不同SNR下的正确识别率.仿真结果表明,在SNR不小于0的情况下,平均正确识别率在95%以上.     

一种基于分层P2P结构的教育资源网格检索模型

基于教育资源网格,讨论了网格的组织结构问题。针对教育资源网格基于层次扩充树结构,提出了一种基于分层P2P结构的教育资源网格分布式检索模型(DRM-HP2P),该模型使用Web Services技术为资源节点的本地检索进行了封装,使用P2P方式进行域内检索,并通过该域内的管理节点向其它管理域转发检索请求,启动多个域内检索,最后将检索结果合并后返回。应用表明,该模型有较高的效率。     

点对点网络及其安全问题分析

P2P网络在短短的几年时间内迅速发展,并且已经深入到计算机网络的许多方面。文章从P2P网络的概念与分类,简要论述了P2P的安全性,指出了今后P2P发展的方向。     

P2P在流媒体中的应用研究

对等网络是目前计算机技术研究领域中比较活跃的一个方向.首先分析了C/S和P2P模式及其优劣,然后具体论述了在P2P系统上采用以树为基础的应用层组播结构及其关键实现,最后针对目前一些流媒体软件中出现的问题给出了解决方法.     

LiF:Mg,Cu和LiF:Mg,Cu,P低温热释光性质研究

LiF:Mg,Cu,P和LiF:Mg,Cu样品主峰温度相近,推断形成样品中相应峰的缺陷有相似结构。同剂量LiF:Mg,Cu和LiF:Mg,Cu,P发光曲线相似,但发光谱中心却差别很大,推测LiF:Mg,Cu,P复合中心与P元素有密切关系。     

P systems generating iso-picture languages

P systems generating rectangular arrays and hexagonal arrays have been studied in the literature, bringing together the two areas of theoretical computer science, namely membrane computing and picture languages. Recently, a new class of picture languages called the class of iso-picture languages generating interesting picture languages has been introduced. In this paper, we develop a class of tissue-like P systems with active membranes as a generative device for iso-picture languages.     

P systems generating iso-plcture languages

P systems generating rectangular arrays and hexagonal arrays have been studied in the literature,bringing together the two areas of theoretical computer science,namely membrane computing and picture languages.Recently,a new class of picture languages called the class of iso-picture languages generating interesting picture languages has been introduced.In this paper,we develop a class of tissue-like P systems with active membranes as a generative device for iso-picture languages.     

Efficient statistical analysis method of power/ground(P/G) network

In this paper, we propose an incremental statistical analysis method with complexity reduction as a pre-process for on-chip power/ground (P/G) networks. The new method exploits locality of P/G network analyses and aims at P/G networks with a large number of strongly connected subcircuits(called strong connects) such as trees and chains. The method consists of three steps. First it compresses P/G circuits by removing strong connects. As a result, current variations (CV) of nodes in strong connects are transferred to some remaining nodes. Then based on the locality of power grid voltage responses to its current inputs, it efficiently calculates the correlative resistor (CR) matrix in a local way to directly compute the voltage variations by using small parts of the remaining circuit. Last it statistically recovers voltage variations of the suppressed nodes inside strong connects. This new method for statistically compressing and expanding strong connects in terms of current or voltage variations in a closed form is very efficient owning to its property of incremental analysis. Experimental results demonstrate that the method can efficiently compute low-bounds of voltage variations for P/G networks and it has two or three orders of magnitudes speedup over the traditional Monte-Carlo-based simulation method, with only 2.0% accuracy loss.     

Maximally parallel attribute on P Systems: Properties and applications

In this paper, we investigate the maximally parallel attribute of P Systems. Some properties of P Systems are introduced, which are the filter property and the enumeration property. The two properties are applied to solving the sorting problem and the Hamilton cycle problem, respectively.     

基于P89LPC935的四相步进电机细分驱动器设计

基于P89LPC935的四相步进电机细分驱动器,细分控制信号由、P89LPC935片内的2路DA输出产生,相电流的开关通过P89LPC935的开漏输出脚控制,相电流采用模拟功放方式控制,电路简单,造价低廉,可根据需要通过对单片机编程,选择端口电平、串口通信、L2C接口通信等多种方式控制步进电机的运行。用于驱动42BYG（H）和57BYG（H）系列小功率四相步进电机,可大幅降低驱动器成本,并降低步进电机在低速状态下的运行噪音。