共享内存在高效进程间通信中的应用研究

在Linux系统中两个或多个进程间通信,是实现计算机内部传递信息的机制,它们之间是同步的关系,多个协作进程间完成数据的共享、消息的交换。文章基于Ubuntu 12操作系统环境,通过共享内存通信的方式设计一种基于多进程的同步关系,它们共享内存的同步通信机制。文章详细描述了该机制的设计原理和实现方式,并采用内核文件shm.h实现了进程同步,通过内存片段共享机制减少多个进程之间的切换时间,实现了共享内存在多进程间的高效通信。     

一种云服务器互连芯片交叉开关的设计与实现

在高端云服务器系统中,计算节点间的互连芯片通过Cache一致性协议将多计算节点互连组成分布式和共享内存空间系统,对接口传输速率和路由交换效率要求较高。文中通过分析Cache一致性协议报文的传输特点和互连网络转发需求,设计实现了一种互连芯片的高阶非对称交叉开关。设计通过了系统级的仿真验证,基于FPGA实现的云服务器互连芯片原型验证系统进行了实际带宽测试和芯片带宽匹配优化。互连芯片流片后的系统实测结果表明,满足功能要求,互连网络处理模块延迟8. 75ns,吞吐率65. 03%,达到了设计目标。     

TI达芬奇软件框架技术的研究与改进

分析了基于分层管理的TI达芬奇软件框架技术,描述了融入共享内存技术进行数据交换的改进方案,在应用该方案的网络可信视频编码器中.实现了双核处理器之间的数据通信和ARM核上不同进程模块之间的大量数据交互.     

流控制传输协议实现技术的研究

参照TCP(传输控制协议)软件的设计方法，提出了SCTP(流控制传输协议)的软件模型。软件结构确立为模块化结构布局，程序框架采用多进程机制，通过消息队列和共享内存技术来实现进程问的通信。至于模块的实现，文中示范性地介绍了实现与新特性相关的控制模块和流引擎模块的要点。     

高性能MMO服务器架构与模式设计

MMO服务器设计过程中,需要关注整体结构、通讯模块和服务器的鲁棒性.结合经典设计模式,讨论MMO服务器构建的关键技术点.采用模块化的构建方法组织服务,通讯模块使用IOCP机制保证网络服务的并发性和高效性.融合油漆工、代理、观察者等多种模式,实现服务模块的低耦合结构.加入共享内存机制和进程通信机制,将服务数据与服务逻辑分离,保证服务器的鲁棒性.     

基于视场合成的成像光谱仪数据采集系统设计

推扫式遥感仪器可以采用多个镜头进行视场合成以提高仪器的总视场.视场合成技术涉及光学、机械、电子学系统技术.电子学系统需要完成多镜头数据的采集、融合及其他处理.在光谱仪地面测试数据采集系统中,每个镜头对应一个独立的数据采集与处理模块.控制模块同步各子模块的数据采集,并通过FIFO接口获取各子模块数据,然后通过PCI数据采集卡发送到PC机中.所有模块插在一个底板中,底板完成模块间的连接.介绍了多镜头下数据采集系统的设计与实现.     

一种基于VLC的可跨平台的播放器系统设计方法

本文旨在提出一种基于开源软件VLC的在机顶盒上可跨平台应用的多媒体播放器系统。以C/S模式,VLC进程作为服务器端等待多媒体解析请求,应用平台端作为客户端向服务端发起播放请求,经进程通信控制模块(IPC)传递播放地址,开启音视频读数据线程并打开底层解码器,之后等待共享内存中视频PES数据量达到起播值SIZE_READ_START。VLC进程获取媒体播放地址后开启媒体容器解析线程。一方面将获取的媒体解码器信息包括音视频编码格式,音视频PID值和文件时长等信息通过IPC接口传回给客户端。另一方面将音视频流PES数据写入分配的共享内存BUFFER供客户端取用。客户端在获取媒体解码信息后配置音视频解码器解码格式。读视频数据线程等待共享内存内数据达到起播阈值后立即开始将数据整块写入解码器缓存,并开启音频流读数据线程。     

在DSP组成的多CPU系统设计中双端口RAM的应用研究

在设计多CPU及其他高速数字处理系统时 ,数据获取及交换是多CPU系统的重要组成部分。当多个CPU对共享内存进行访问时不发生冲突是系统设计能否成功的关键。双口RAM是一种性能优越、能解决访问冲突的器件。本文讨论了以CY7C144为双口RAM在深井泵多CPU并行控制系统中的具体应用     

多色焦平面图像融合技术分析与应用展望

在介绍多色焦平面阵列技术发展现状的基础上,讨论了该技术应用在图像融合系统中的优势.然后分析了基于该技术的图像融合系统的主要组成模块,包括多色焦平面探测器组件、数据传输模块和图像融合模块等.重点研究了图像融合模块的3种主要实现方案,单DSP或多DSP并行处理方案,DSP+FPGA处理方案以及大规模FPGA处理方案.最后给出了多色焦平面图像融合系统在大数据量传输、红外多源图像融合新算法、小型化和智能化等方面的发展趋势及其在机载光电系统、多光谱遥感探测、分布孔径红外传感器系统(DAIRS)和精确制导等方面的应用.     

基于并行队列的众核平台入侵检测系统

本文通过分析和总结以Suricata为代表的现有的主流并行化入侵检测系统的体系结构,并对Suricata的3种工作方式结合现有tilera系列硬件平台的硬件特点进行了理论分析.提出了众核入侵检测系统的设计要点.并设计了一种基于非统一内存访问与内存池的入侵检测结构.该结构将传统的流水线模式与并发模式相结合,在尽可能少地进行核间通讯的前提下,最大程度地提升了单核的内存使用效率和cache命中率.同时使用共享内存池进一步提高了读写密集情况下的内存使用效率,使用改进的无锁通讯队列保证了核间通讯的效率,使得该架构在众核平台具有很高的实用性,其主要模块的设计思想也具有一定程度上的可移植性.本文最终设计并实现了一个高效的基于众核平台的入侵检测系统.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks