LTE＆WiMAX： 将踏上GSM＆CDMA的足迹？

有些人认为它们互为补充，有些人则认为它们将自己的触角都伸向了对方。毫无疑问，它们都将另一只眼睛盯准了对方的领域     

数字电视显示图像的同心度、重显率和过扫描

讨论了数字电视显示图像的同心度、重显率和过扫描，描述了它们的测量方法，重点分析了它们之间的内在联系，以及用它们来衡量显示图像质量的优缺点。实测表明，正确调整和测定这些指标，对保证数字电视图像主观效果具有重要作用。     

三百万的诱惑诺基亚5610 XpressMusic VS三星SGH-E950

这一次同时到了两款320万像素级别的手机，虽然它们都不是以拍照为功能卖点的手机，但是我们仍然希望将它们放到一起来对比一下，因为它们都走时尚年轻的路线，机型中都加入了很多在手机产品里比较新鲜的元素。而且，最重要的是它们都是目前比较热门的机型，很多用户在这两款机型之间犹豫不决。所以，现在就让我们来看看，它们有什么功能，使用表现如何，分别适合怎样的用户选择。[编者按]     

软件无线电体系结构研究

软件无线电体系结构是实现软件无线电的具体设计结构，包括软件和硬件体系结构两方面，它们是软件无线电技术的核心之一。本文比较全面地描述了目前实用的软件无线电软硬件体系结构，提出了具体的划分方法，并比较了它们的性能，它们将对相关问题的研究起到一定借鉴作用。     

现代单模光纤的改进及其制造技术

回顾了通信用光纤的发展历史，综述了最新发展的几种单模光纤，阐述了它们的几个关键参数与应用范围，描述了它们的制造技术。     

民意取样——后果很严重！：电子病对健康的影响

不知不觉，电子产品已成为了我们生活中不可或缺的东西，我们享受着它们带给自己的方便与快捷，感叹着它们功能的强大与实用。但是，我们是否想过它们的不足之处，特别是对自己健康的悄悄侵蚀？在此，我们通过一周的电话和网络探访，为你呈献了这份真实的调查报告……     

精灵的细语——昆虫摄影

夏季到了，人们因为天气炎热纷纷躲进空调房里，但是这个季节却是一些小家伙--昆虫们最活跃的时候，它们开始忙碌着觅食、交配、交卵……在很多场合，我们总能和它们不期而遇，你是否早已熟视无睹而无动于衷，或者觉得它们的世界太小与自己毫不搭界……但是，     

升舱

三款经典产品的升级之作为消费者带来了更多的选择，它们不仅仅带来了外观上的改变，更主要的是它们内在的提升。     

面向对象设计和面向对象编程

本文简要介绍了面向对象设计和面向对象编程，包括它们的特点和不足，以及它们在软件工程中的重要意义。     

光纤光栅的几种调谐方法

以光纤光栅滤波器的调谐为例，研究了6种以应力拉伸或压缩为手段的光纤光栅的调谐方法，分析了它们的基本原理，并对它们的优缺点进行了比较。     

Strongly ideal secret sharing schemes

We define strongly ideal secret sharing schemes to be ideal secret sharing schemes in which certain natural requirements are placed on the decoder. We prove an information-theoretic characterization of perfect schemes, and use it to determine which access structures can be encoded by strongly ideal schemes. We also discuss a hierarchy of secret sharing schemes that are more powerful than strongly ideal schemes.     

Selective-repeat-ARQ schemes for broadcast links

The authors propose retransmission error control schemes for broadcast channels. In their selective-repeat-ARQ (automatic repeat request) method, they incorporate some aspects of implementation that they believe were ignored by all the previous work. Based on this protocol, they also propose a type-2 hybrid ARQ scheme that uses parity retransmission. They apply the dynamic programming optimization technique of Wang and Silvester (1987), with some modification, to their schemes. Analysis shows that their schemes outperform all the existing schemes. As special cases of their proposed schemes, the authors can obtain point-to-point ARQ schemes which also outperform all the existing point-to-point schemes. Thus, their schemes extend the useful range of retransmission error control schemes for these channels     

Fundamental Schemes for Efficient Unconditionally Stable Implicit Finite-Difference Time-Domain Methods

Generalized formulations of fundamental schemes for efficient unconditionally stable implicit finite-difference time-domain (FDTD) methods are presented. The fundamental schemes constitute a family of implicit schemes that feature similar fundamental updating structures, which are in simplest forms with most efficient right-hand sides. The formulations of fundamental schemes are presented in terms of generalized matrix operator equations pertaining to some classical splitting formulae, including those of alternating direction implicit, locally one-dimensional and split-step schemes. To provide further insights into the implications and significance of fundamental schemes, the analyses are also extended to many other schemes with distinctive splitting formulae. Detailed algorithms are described for new efficient implementations of the unconditionally stable implicit FDTD methods based on the fundamental schemes. A comparative study of various implicit schemes in their original and new implementations is carried out, which includes comparisons of their computation costs and efficiency gains.     

Maxwell 方程组的多辛算法

Maxwell方程在线性、各向同性、均匀、无源的介质中具有自然的多辛结构,可以表示为多辛Hamilton系统。Maxwell方程的多辛算法即对Maxwell方程在时间、空间同时进行保辛离散得到相应的差分格式。文中给出了5种麦克斯韦方程的多辛算法,分析并比较了这5种方法的数值色散特性。数值计算结果表明这些算法能很好地保持Maxwell方程的离散全局能量守恒特性。     

代理多重签名:一类新的代理签名方案

在代理签名方案中,代理签名人可以代表原始签名人生成签名.然而,在已知的各种代理签名方案中,代理签名人生成的每个代理签名都只代表一个原始签名人.在有些情形,需要一个代理签名能够同时代表多个原始签名人,而已知的代理签名方案都不能满足这个需要.本文给出 一类称为代理多重签名的新代理签名方案.在这种新方案中,一个代理签名人可以同时代表多个原始签名人在文件上签名.     

Congestion control schemes for reverse link data transmission in multimedia CDMA systems

We investigate the congestion control schemes for reverse link in code division multiple access multimedia systems. We propose four schemes according to the control bit setting methods at base and the rate decision schemes in mobiles. With the proposed schemes, all mobiles control their transmission power and rate simultaneously. As the aggregate effect, the cell-wide congestion control is accomplished. The performance of systems with the proposed schemes are evaluated using computer simulation and compared with each other. Under a congested situation, the proposed schemes guarantee the priority of real-time traffic over non-real-time traffic and prevent an excessively high error rate for real-time services. We describe and evaluate the proposed schemes under the system model assumption based on 1xEV-DO and cdma2000. However, the proposed schemes can be also applied to wide-band code division multiple access systems with minor modification.     

多服务器多队列系统调度方案的性能分析

本文讨论了多服务器多队列系统的调度、选择控制方案,并提供了这些方案的随机Petri网模型.这篇论文强调这些方案的设计和性能分析.为了掌握这类系统调度、选择控制方案的设计,我们讨论了方案性能优劣性的成因.本文的多服务器多队列系统模型、调度和选择控制方案和性能分析技术可以应用于这类系统的性能评价.     

Robust rotation-invariant texture classification: wavelet, Gaborfilter and GMRF based schemes

Three novel feature extraction schemes for texture classification are proposed. The schemes employ the wavelet transform, a circularly symmetric Gabor filter or a Gaussian Markov random field with a circular neighbour set to achieve rotation-invariant texture classification. The schemes are shown to give a high level of classification accuracy compared to most existing schemes, using both fewer features (four) and a smaller area of analysis (16×16). Furthermore, unlike most existing schemes, the proposed schemes are shown to be rotation invariant demonstrate a high level of robustness noise. The performances of the three schemes are compared, indicating that the wavelet-based approach is the most accurate, exhibits the best noise performance and has the lowest computational complexity     

有向签名方案

本文提出了许多称此有向签名的新方案，在这些方案中，只有特定的收方才验证签名的正确性，我们在ＥｌＧａｍａｌ型签名方案和相应的具有报文还原功能的签名方案（称作ＭＲ型签名方案）上构造了五个有向签名方案，分析并讨论了这些方案的安全性。     

Analysis of random PWM switching methods for three-level powerinverters

This paper presents a generalized theory which covers both two-level and three-level random pulsewidth modulation (RPWM) schemes. Various three-level RPWM schemes with low switching frequency are presented and compared with two-level schemes. Three-level RPWM schemes have less discrete harmonics and continuous noise than two-level RPWM schemes. They have desirable spectral characteristics and can be employed in high-voltage inverter-fed motor drives. Measurements have confirmed the theory and the attractive features of three-level RPWM schemes