从“棱镜门”事件看国家安全与个人信息保护

因斯诺登引发的美国"棱镜门"事件令国家机关收集个人信息的行为受到质疑,其性质可归结为国家安全与个人信息保护之间的矛盾。技术的发展是国家收集个人信息的可行性条件,法律的规定则为国家收集个人信息提供制度保障。国家安全与个人权利之间既有激烈的矛盾冲突,也存在一致性。为了实现国家安全与个人权利之间的平衡需要采取相关的措施,以防范国家机关在收集个人信息过程中出现侵犯个人权利的不法行为。     

S7-200 PLC与PC间的串口通信

本文介绍了S7-200 PLC的自由口通信模式及其设置,以及基于VB6.0的PLC与PC间的串口通信.     

突围与陷落——当代女性"个人化写作"的困境

以陈染、林白为代表的当代女性"个人化写作",在女性话语模式和女性欲望的书写上,突破了女性作为人的主体意识与本能欲望被强大的男权中心社会意识、叙事语体所覆盖的局面,挣脱男性话语无所不在的桎梏,挑战男权文化。然而女作家们在"私人空间"中的"身体书写",在对男性社会性别角色进行大胆的反抗、突围的同时,也在自身的局限中,无可奈何地陷落于男权文化的陷阱。     

中间件及其在电信计费信息系统中应用

介绍了中间件的种类和范畴，指出了髯类中间件在实际应用中存在的诸如中间件升级或中间件选择不当等问题，通过支持异构平台和分布式编程，平衡资源负载和代码重用等方面说明了中间件的优点，指出了C／S两层结构直接存取系统资源所存在的安全和吞吐量等问题，并由此比较了在应用中使用两层和多层体系结构的中间件的不同之处，利用基于中间件的多层次结构对计费系统中目前所面临的系统资源、数据库吞吐量、以及安全等关键问题作了研究，并由此给出了利用中间件技术来解决这些问题的途径。     

社区型多媒体通信用户高速接入技术解决方案

解决好社区多媒体通信的高速接入问题是接入技术的重点，因此，综述了ADSL，Cable Modem,HomePNA等3种用户接入技术，在分析和比较了这3种技术基础上，提出了ADSL＋HomePNA社区型多媒体通信用户高速接入的解决方案，为用户高速接入技术开辟了新的思路。     

Metabolomics Approach on Non-Targeted Screening of 50 PPCPs in Lettuce and Maize

The metabolomics approach has proved to be promising in achieving non-targeted screening for those unknown and unexpected (U&U) contaminants in foods, but data analysis is often the bottleneck of the approach. In this study, a novel metabolomics analytical method via seeking marker compounds in 50 pharmaceutical and personal care products (PPCPs) as U&U contaminants spiked into lettuce and maize matrices was developed, based on ultrahigh-performance liquid chromatography-tandem mass spectrometer (UHPLC-MS/MS) output results. Three concentration groups (20, 50 and 100 ng mL⁻¹) to simulate the control and experimental groups applied in the traditional metabolomics analysis were designed to discover marker compounds, for which multivariate and univariate analysis were adopted. In multivariate analysis, each concentration group showed obvious separation from other two groups in principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) plots, providing the possibility to discern marker compounds among groups. Parameters including S-plot, permutation test and variable importance in projection (VIP) in OPLS-DA were used for screening and identification of marker compounds, which further underwent pairwise t-test and fold change judgement for univariate analysis. The results indicate that marker compounds on behalf of 50 PPCPs were all discovered in two plant matrices, proving the excellent practicability of the metabolomics approach on non-targeted screening of various U&U PPCPs in plant-derived foods. The limits of detection (LODs) for 50 PPCPs were calculated to be 0.4~2.0 µg kg⁻¹ and 0.3~2.1 µg kg⁻¹ in lettuce and maize matrices, respectively.     

Experimental Study of Red-, Green-, and Blue-Based Light Emitting Diodes Visible Light Communications for Micro-Projector Application

In this research, an experimental short-range visible light communication link using red-, green-, and blue-based light-emitting diodes (LEDs) for portable micro-projector applications is presented. A Reconfigurable design of a post-equalizer aimed to improve the inherent narrow modulation bandwidth of red-, green-, and blue-based LEDs has been experimentally implemented, and its effectiveness with optical filters at the receiver is investigated. Reflective liquid-crystal-on-silicon-based micro-projection architecture, widely used in portable micro-projectors, was set up to evaluate the proposed visible light communication system. The measurement results demonstrated that a significant aggregative bandwidth improvement of 162 MHz as well as an aggregative data transmission rate of nearly 400 Mb/s can be achieved by using a non-return-to-zero–on-off keying (NRZ–OOK) modulation scheme based on only one polarization state of incident light without any offline signal processing.     

非高斯畸变对星间光通信瞄准偏差的影响

 提出了一种针对星间激光链路反射式光学天线的非高斯畸变模型,利用该模型研究了波前畸变对系统瞄准偏差的影响,并且与高斯型波前畸变所得结果进行了对比。理论分析和仿真结果表明：对于高斯型和非高斯型畸变,系统的瞄准偏差都会随着畸变范围的增大而增大,随着畸变位置相对光束中心距离的增大先增大后减小。当畸变形状可以用其平均变化量来近似时,随着畸变深度的变化,瞄准偏差呈周期性变化趋势,振荡周期峰值的包络与畸变形状有关;对于不能简单用均值变化量代替其形状的畸变,随着畸变深度的增加,瞄准偏差的变化不具有周期性。仿真结果显示:对口径为0.25 m的反射式光学天线,当遮挡比为0.1时,如果畸变范围超过0.01 m×0.01 m,系统将会产生比较明显的瞄准偏差。     

基于异步延迟采样的光通信性能监测方法

基于异步延迟采样和人工神经网络统计学习提出了一种光通信性能监测方法。通过对高速光信号进行异步延迟采样,获得信号二维幅度直方图,然后提取其中特征参数并对人工神经网络进行训练,最后以人工神经网络的预测输出实现对光信号损伤的监测。构建10 Gb/s非归零码开关键控,40 Gb/s光学双二进制码和归零码差分移相键控光通信仿真系统,并对光信噪比、色散和偏振模色散损伤进行监测。仿真结果表明,所提方法对被监测光信号的速率、码型调制格式透明,可同时准确监测多种并存的传输损伤,损伤参数监测误差小于5%。该方法具有电域处理带宽要求低、采样机制简单的特点,适用于分布式在线光性能监测。     

基于多层神经网络控制的动态自适应播放

基于流媒体客户端缓冲的被动变化可以通过自适应媒体播放(AM P)技术修改播放速度来调节,为了减轻AM P中速度突变对播放质量的影响,提高变速的性能,提出了一种基于多层神经网络控制的AM P方法,产生随当前缓冲动态变化的速度,并且保持缓冲稳定在一定的范围内。该方法引入了多层神经网络控制结构,并采用反向传播学习算法(BP)进行离线训练。仿真结果表明:该方法产生的速度平均幅值和变化增量可以减少0~100%,性能比原AM P方法更好。