短信问题交流

Qwoaibadi我要通过短路主板的CMOS跳线来清除BIOS设置的开机密码,可反复将跳线状态设为短路位置,开机后发现开机密码仍存在,如何解决该问题?A从你说的现象来看,应该是在短接CMOS跳线时,没有切断主板的供电造成的。你可将主板电源线拔下,然后进行跳线设置,最后再将CMOS供电电池拆下,让CMOS因得不到供电而使内部信息自行丢失。     

基于多模板匹配的室性早搏判别算法

提出一种基于可变宽度模板的多模板匹配的室性早搏判别算法。该方法通过样本数据创建初始模板库,根据不同的RR间期确定模板宽度,使用基于模板队列匹配和模板库匹配的二级匹配策略,利用相关系数和RR间期比相结合的算法检测室早,模板库可自动扩充。经MIT-BIH心律失常数据库测试,该算法达到了98.66%的灵敏度(正确率),平均错误率为1.11%。     

基于信息增益的Web人物关系抽取*

针对人物关系抽取中的效率与准确性问题进行了研究,提出一种基于信息增益的轻量级Web人物社会关系提取方法。它通过计算初始关系元组的关系描述词的信息增益值进而确定元组上下文位置并据此创建相应的关系抽取模板,最后利用模板实现了Web的人物关系自动提取。针对中文语义上存在相似性的问题,引入了基于《同义词词林》与基于《知网》的人物关系描述词扩展方法。对于某一句子内包含多个人物实体且存在多种人物关系的情况,提出了一种基于模板上下文信息增益值模糊匹配的方法来抽取符合特定人物关系的人物实体。实验结果证明：该方法的平均准确率为89.92%,平均召回率为84.64%。基于信息增益的Web社交网络人物关系抽取方法能有效地完成实时语料中的关系抽取任务。     

基于单片机的多功能测温前置电路

本文介绍了一种测温仪前置电路,可满足多种温度信号测控的功能,采用了硬件跳线器改变接入线路,同时又可通过软件设计,对其进行选择,具有较广的使用范围。     

光纤跳线的质量、可靠性和性能

通过选择最佳的元件、采用最好的设备与程序进行终接与抛光来保证光纤跳线的质量、可靠性和性能。这些元件和程序必须保证跳线满足或超过所有相关行业规范的要求、本文描述了适用行业规范中的标准相关性，以及物理参数的重要性和物理参数与跳线性能的关系     

84GS到86GT的神奇变身——盈通G8486跳线版显卡

盈通最近推出了一款售价仅为399元的G8486跳线版TC512GD3显卡,用户只需通过一个简单的跳线,就可让其从GeForce8400GS“变身”为GeForce 8600 GT．从而获得性能上的提升。为了实现这样的“变身”,该显卡使用了GeForee 8600 GT的G84核心,不过核心频率较低,只有450MHz。通过简单的跳线设置,我们可以将它强行运行在Turbo模式下,     

高脂血症分类特征选择算法研究

以高脂血症文献分类为背景,通过对传统特征选择算法的研究,结合特征出现概率、特征与类别的相关度,提出一种基于二类信息差值的特征选择方法。使用该算法及k近邻距离分类法在高脂血症文献数据集上进行分类,实验显示该算法优于文档频率和信息增益,可提高文本分类的查准率。     

一种基于模板匹配的电路照片拼接方法

鉴于实际工作中,经常需要将多幅图象拼成一大幅大图象的问题,提出了一种针对显微照片的新拼接方法。该方法是应用模板匹配技术来实现图象的自动拼接,由于是通过利用图象信息来选择模板,从而为模板匹配的定位创造了条件,该方法分为模板选择、模板匹配和图象拼接3步。实际运用结果表明,该方法简单易行,在电路照片的拼接中,定位较准确,且拼接效果好。     

可变通道可变速率A／D变换板的设计与实现

本文介绍的A/D变换板输入通道数任意选择。各通道前量放大器增益可灵活调整,输入电平范围宽广。各通道变换速率互不相同,并可灵活改变,通道均为严格等间隔采样。利用单路D/A变换可监视任一通道A/D变换结果。该模板可直接插入PC/XT/AT及其兼容机中作为A/D卡使用。本变换板利用多片高速A/D变换器异步并行工作,达到了甚高速A/D变换器的变换速率。     

海洋气象观测用低功耗智能型气压传感器设计

针对当前气压传感器功耗偏大、输出数据单一、灵活性差等缺点,设计了一款低功耗、输出方式灵活的智能型气压传感器。以ATmega16L单片机为主控芯片,通过SPI总线读取气压和温度的原始测量值,计算得到精确大气压值;采用精细化的软硬件省电设计方法,实现了系统的低功耗;通过跳线选择数据输出方式,增加了产品的灵活性。该传感器具有高精度、高稳定性、智能性、低功耗和便携式等特点,可独立使用,也可用于其他需要气压测量的设备中。     

基于量程自动转换技术的数据采集系统

针对传感器实验台输入信号范围宽的特点，研制了以89C51RD2单片机为核心数据采集系统。该系统采用了可编程放大器、AD574及其保护电路，结合软件控制量程自动转换电路，把输入任意范围的采集信号自动进行调整放大倍数，使数据采集系统始终具有较高分辨率，较强的自适应能力。此外，通过该系统与PC机进行通信，采集的数据可以在计算机上实时动态显示。     

一类不确定非线性系统的鲁棒输出反馈跟踪

讨论了一类严格反馈型不确定非线性系统的输出反馈跟踪问题. 所讨论的不确定性不满足线性增长条件. 先设计高增益观察器估计输出偏差的微分, 并将由此获得的信号的符号用于变结构观察器, 随后用backstepping过程设计输出反馈控制器. 得到的控制器可以保证闭环系统的所有信号都是有界的, 且跟踪误差可以任意地小.     

涡街流量传感器信号处理方法研究

设计一种基于变增益运算放大器和DSP数字信号处理单元的新型涡街流量计信号处理电路.利用DSP上集成的模拟数字转换电路(A/D)实时检测涡街流量计传感器输出信号的幅度和频率,采用数字模拟转换电路(D/A)对变增益运放进行控制,控制传感器输出信号幅度的相对稳定.针对涡街流量计输出信号的频率特性,设计基于DSP的FIR滤波算法,实现输出信号噪声的初步抑制,削弱原始信号中强噪声干扰.滤波后信号由DSP进行频率信息的精确计算以及流量的解算.实验结果表明,变增益运算放大电路有效解决了涡街流量计传感器输出信号幅度变化范围大而造成的放大电路复杂,分段放大信号幅度不连续等问题;采用DSP进行数字滤波及频率计算,实现了信号中噪声的抑制以及高精度流量解算.     

半实物综采实操平台可扩展数据采集系统设计

多种型式的半实物实操平台逐步应用于矿山设备培训,但针对具体被仿真设备开发特定数据采集系统的方式存在开发周期长、资源浪费等问题。在分析半实物综采实操平台数据采集需求的基础上,设计了一种可扩展数据采集系统。该系统以由主板和扩展板组成的数据采集板为核心,主板和扩展板分别能采集8路模拟量和16路开关量,通过主板和扩展板不同组合方式可实现一主多扩和一主多从多扩模式,分别适用于以开关量为主和模拟量为主的数据采集。该系统可满足多种型式的半实物实操平台数据采集需求,具有一定程度的通用性。     

深井探查装置专用字符叠加板的设计与实现

文章介绍了一种基于CPLD的深井探查装置专用字符叠加板，不仅可完成探测器下放深度测量，更可将探测器的下放深度实时显示于视频图像上，在视频信号中断时仍可继续显示距离信息。它可以通过RS232口与其它数据采集系统同步工作，实现距离测量与数据采集相关。经实际应用表明，该板稳定可靠，测量精确，可在油田、水利打井等行业中推广使用。     

基于FPGA的便携式VI曲线航空电路板测试装置

目前对便携式VI曲线航空设备电路板测试装置的研究较少,不能满足外场环境下的应急测试需求;针对这一问题,提出了一种放置于手提式机箱中的便携式VI曲线电路板测试装置的设计方案,以FPGA为主控器件设计测试板件,以给定程序可调的激励信号、采集在各种激励信号下的电流信号、并把电压电流数据通过USB接口传送给上位机,上位机采用迷你工控机进行设计,在接收到电压电流数据后,进行数据处理并在显示屏上实时绘制相应的以电压电流为横纵坐标的图像信息;试验结果表明,针对不同类型的阻抗元件,装置可以绘制出相应类型的VI曲线,从而识别出元器件的不同状态;装置小巧轻便,操作简单,可以运用于外场机载电路板件的测试诊断。     

KD10A10位高速数据采集卡

讨论了一种商品化的高速、１０位分辨率的数据采集卡的设计要点，它包括模拟输入、Ａ／Ｄ转换、数据缓存、重复采集控制，计算机接口等电位的设计，可广泛应用于雷达、声纳等各类周期或非周期信号的采集与处理领域。该采集卡可直接插在各类计算机的扩展槽中，构成一功能完善的高速、高精度、大存贮量、可重复采集的数据采集系统。     

Bulletin boards and net sites

Should a BB or net access provider be liable for copyright infringement when a user posts infringing material on user newsgroup or forum? Several recent court decisions have addressed the liability of bulletin board operators and related organizations for copyright infringement as a result of user postings of copyrighted material. The most recent decision (Nov. 1995) is the first to address the copyright liability of on-line service providers, at all. It is also the first to address in depth the liability of bulletin board operators who gain Internet access via such online service providers     

Touch-down and take-off characteristics of the long jump performance of world level above- and below-knee amputee athletes

The aims of this study were to establish the take-off characteristics of long jump performance of disabled amputee athletes, and to establish to what extent amputee athletes conform to a model of performance defined for elite able-bodied athletes. The jumps of 8 male below-knee (trans-tibial) and 8 male above-knee (trans-femoral) amputee athletes who competed in the finals of the long jump at the 1998 World Disabled Championships were recorded in the sagittal plane on video (50 Hz). Approach speed was measured using a laser Doppler system. The best jump for each athlete was digitized, and kinematic data from the key instants of touch-down (TD), maximum knee flexion (MKF) and take-off (TO) were obtained. Amputees demonstrated a lower approach speed and jumped less far than able-bodied athletes although below-knee amputees performed better than above-knee amputees. For each amputee group there was a significant (p < 0.05) linear relationship between approach speed and distance jumped. With the exception of their slower horizontal speed and greater negative vertical speed at touch-down, below-knee amputees demonstrated characteristics of technique that were similar to elite able-bodied long jumpers. Above-knee amputees at touchdown had a more upright trunk, smaller hip and knee angles and consequently a smaller leg angle. This was attributed to the difficulty of taking off on the last stride on the prosthetic limb. Consequently, above-knee amputees were less able to gain vertical velocity during the compression (TD-MKF) phase, but were able to compensate for this by using a greater hip range of motion during the extension (MKF-TO) phase. It was concluded that below-knee amputees displayed the same basic jumping technique as elite able-bodied long jumpers, but above-knee amputees did not. These findings have implications for the training and technical preparation of amputee long jumpers.     

Touch-down and take-off characteristics of the long jump performance of world level above- and below-knee amputee athletes

The aims of this study were to establish the take-off characteristics of long jump performance of disabled amputee athletes, and to establish to what extent amputee athletes conform to a model of performance defined for elite able-bodied athletes. The jumps of 8 male below-knee (trans-tibial) and 8 male above-knee (trans-femoral) amputee athletes who competed in the finals of the long jump at the 1998 World Disabled Championships were recorded in the sagittal plane on video (50 Hz). Approach speed was measured using a laser Doppler system. The best jump for each athlete was digitized, and kinematic data from the key instants of touch-down (TD), maximum knee flexion (MKF) and take-off (TO) were obtained. Amputees demonstrated a lower approach speed and jumped less far than able-bodied athletes although below-knee amputees performed better than above-knee amputees. For each amputee group there was a significant (p < 0.05) linear relationship between approach speed and distance jumped. With the exception of their slower horizontal speed and greater negative vertical speed at touch-down, below-knee amputees demonstrated characteristics of technique that were similar to elite able-bodied long jumpers. Above-knee amputees at touchdown had a more upright trunk, smaller hip and knee angles and consequently a smaller leg angle. This was attributed to the difficulty of taking off on the last stride on the prosthetic limb. Consequently, above-knee amputees were less able to gain vertical velocity during the compression (TD-MKF) phase, but were able to compensate for this by using a greater hip range of motion during the extension (MKF-TO) phase. It was concluded that below-knee amputees displayed the same basic jumping technique as elite able-bodied long jumpers, but above-knee amputees did not. These findings have implications for the training and technical preparation of amputee long jumpers.