Chip-to-chip optical interconnects: more bandwidth,more powerful

This paper aims to compare the electrical chip-to-chip interconnects and optical interconnect from the physical view and the computing performance view. Using transmission line theory, the constraints of transmission bandwidth is obtained. The calculation indicates that ideal maximum electrical capacity density is much lower than the experimental optical interconnected one. In this calculation, all the parameters come from International Technology Roadmap for Semiconductors (ITRS) and reports of world-class laboratories. Compared with bandwidth, application is a more important factor, which has great influence on the technology development direction and deployment in the real scenarios. Therefore, we take fast Fourier transform (FFT) computation as an example to study whether and how the optical interconnect technology has influences on the computing performance. One of most popular topology, mesh architecture is evaluated in this paper. The results illustrate the bandwidth increase will lift up the speedup and efficiency, especially for the clusters with many processors working cooperatively. From the above analysis, it is shown that the unique features of optical interconnects make it possible to provide more bandwidth, and then bring great advantage to computing performance.     

Energy efficiency based multi-relay selection and power allocation in OFDM cooperation networks

Getting along with the improvement of green communications, the energy efficiency （EE） of wireless network becomes more and more important. However, in nmlti-relay-assisted systems, the related work obviously depends on the end-to-end performance, whereas EE of relays has not attracted enough attention. The authors propose an orthogonal frequency division multiplexing （OFDM） multi-relay system based on amplify and forward （AF） mode. Taking incorporating EE and remaining energy as factor, decision criteria of attending cooperation is designed. The EE based asynchronous power iteration method is presented, and the existence and convergence of nash equilibrium （NE） is proven. Furthermore, a joint algorithm in subcarrier pairing, relay selection and power allocation is given. Genetic algorithm （GA） and iteration method are integrated to improve the convergence speed additionally. Simulation demonstrates the obvious improvement of EE, decrease of power consumption and increase of lifetime in relays of this algorithm with the constraint of minimum data transmission rate.     

光因特网体系结构与模型分析

在分别支持单跳连接和多跳连接的核心光网络的条件下,对光因特网的体系结构进行了分析和讨论,比较了各种不同的互联模型,对网络建设具有一定的指导意义。     

数据库原理课程中SQL语言的检索分析

含有group by子句的select语句是数据库原理课程中教学的重点,文章结合笔者多年的教学经验,从学生学习和实验时存在的常见问题入手,总结了教学过程中的一些具体做法和体会,旨在提高学生的学习兴趣,培养其自主学习的能力,进而优化教学效果。     

Joint use of time-domain and windowed method for design of modulated DFT filter banks

A novel and efficient technique to design modulated discrete Fourier transform （DFT） filter banks is introduced in this paper. The proposed method first relaxes the limits that the synthesis filters are the time-reversed version of the analysis filters and then adopts the time domain formula of the perfect reconstruction property as the solution to design the synthesis filters. The prototype filter in analysis filter banks is designed based on Fourier-Kaiser window approach. Simulation results show that the designed filter banks approximately satisfy the perfect reconstruction with controllable reconstruction errors.     

面向数字化学习环境的电子商务课程项目设计

数字化学习环境是一个基于网络资源的探索学习、协作学习的系统。它通过构建数字化学习网站,向学习者提供大量的学习资源,让学习者自己选择和确定学习的内容或进行研究项目设计,自己收集、分析并选择信息资料,去解决学习中的问题。通过《电子商务》课程的数字化实验教学设计为例,对促进数字化学习的条件进行研究,把握数字化学习的特点和规律,加强系统数字化学习工具和环境的设计,把促进数字化学习的策略整合到相应的课程中,以激发学生利用数字化资源进行学习的动力,取得预期的学习效果。     

M-Sequence for Reducing Peak-to-Average Power Ratio in PTS-OFDM Systems

1　ＩｎｔｒｏｄｕｃｔｉｏｎＯｒｔｈｏｇｏｎａｌＦｒｅｑｕｅｎｃｙＤｉｖｉｓｉｏｎＭｕｌｔｉｐｌｅｘｉｎｇ(ＯＦＤＭ) [1～5] ｉｓａｐｒｏｍｉｓｉｎｇｔｅｃｈｎｉｑｕｅｆｏｒｈｉｇｈｄａ ｔａ ｒａｔｅｔｒａｎｓｍｉｓｓｉｏｎ ,ｅｓｐｅｃｉａｌｌｙｉｎｗｉｒｅｌｅｓｓｃｏｍｍｕｎｉ ｃａｔｉｏｎｓｙｓｔｅｍｓ,ｗｈｉｃｈｃａｎｅｆｆｅｃｔｉｖｅｌｙｍｉｎｉｍｉｚｅＩｎ ｔｅｒｓｙｍｂｏｌＩｎｔｅｒｆｅｒｅｎｃｅ (ＩＳＩ)ｃａｕｓｅｄｂｙｄｅｌａｙｓｐｒｅａｄａｗｉｎｇｔｏｍｕｌｔｉｐａｔｈｆａｄｉｎｇ .…     

刀体破损检测技术在划片机中的应用

介绍了应用于半导体全自动晶圆划切设备中的刀体破损检测方法,在理论分析与计算的基础上制定检测方案,通过大量数据分析与处理,设计出抗干扰性强的数字滤波器,降低了系统误报率,提高了设备稳定性,保证了划切质量。     

网络技术的实时进化

Ｉｎｔｅｒｎｅｔ 揭开了“网络时代”的序幕,但只是“初级阶段”,Ｉｎｔｅｒｎｅｔ 在“实时性”和“安全性“方方面有着自身不可克服的缺陷。因此在跨世纪之际,推动“网络技术”的”实时进化“,使网络具有“实时性”和“安全性”的特征,已成为新的使命。目前这种进化已在国内外启动,特别是ＴＩＮＡ 技术以及起源于我国的ＴＩＭＮＡ 技术,富有适应时代发展要求的生命力,成为２１ 世纪的“网络技术”。