Trusted auditing method of virtual machine based on improved expectation decision method

Whether the cloud computing environment is credible is the key factor in the promotion and effective use of cloud computing.For this reason,the expected value decision method in risk decision-making was improved.The usage scenarios was redefined,the cost and benefit of audit scheme was digitized,and a virtual machine trusted auditing strategy based on improved expectation decision method was proposed.Several levels of security protection for the user virtual machine was provided,and the optimal audit scheme was selected autonomously according to the security protection level chosen by the user for the virtual machine.The virtual machine introspection (VMI) technology was used to obtain the virtual machine information that needs to be audited.The designed encryption mechanism was used to protect the security of users selected security protection level,so as to ensure the security of user virtual machine selection audit strategy.Finally,the simulation results show that the scheme has good performance and validity.     

电路课程的历史、现状和前景

电路课程是高等学校电工程和信息类专业,甚至其它专业的一门重要的专业基础课。该课程的历史悠久,许多内容已相当成熟。但由于电子技术和信息技术的飞速发展,本课程仍然需要更新与改革。关于“电路课程如何更新与改革”这一话题,全世界有关院校都在热烈讨论。本文试图从回顾电路理论的发展过程中,从我国电路课程的演变中,从国际上最新发展动...     

基于有线电视网络平台视频点播技术的实现

通过对有线电视网络的频带划分、拓扑结构的介绍以及真视频点播 (T -VOD)技术对通信网络要求的分析 ,深入剖析T -VOD技术在有线电视网上的实现策略 ;另外通过对T -VOD系统以及N -VOD系统典型实现的体系结构和性能特点的分析 ,全面地总结了有线电视网上视频点播技术的实现方案 ,并最终提出有线电视网上实现双向数字业务的一种构想     

基于嵌入式系统和PL2000A型调制解调器的电力线载波通信接口设计

电力线通信存在信号衰减快、线路阻抗经常波动等诸多问题,使得通过电力线通信有较大的困难,PL2000A型电力线扩频载波通信专用电路能为此类问题提供较好的解决方案.介绍基于嵌入式系统和PL2000A的载波通信功能的应用接口,分析基于该电路的低压电力线载波通信应用的设计原理,给出相应的电路图和部分软件代码.     

全球宽带接入市场发展趋势

从用户数持续快速增长、宽带用户数最多的国家和地区、宽带用户增量、宽带用户增长率以及宽带业务普及率等5个方面阐明了全球宽带接入市场的总体情况。分析指出宽带接入技术发展趋势．DSL在近两年内仍将占据主流地位。介招了宽带增值业务发展情况。     

具有语音合成功能的嵌入式车载终端的设计

通过了解当前机动车数量与车载终端的特点,提出一种具有语音服务功能的车载终端,使终端具有人性化与智能化的特点.设计了一个基于XF-S4240语音模块和Smart ARM2200嵌入式平台的GSM Modem SMS语音合成系统,经实测语音合成效果良好,说明语音合成技术是一种具有良好应用价值和广阔市场前景的技术.     

智能封堵器水上通信中单片机系统电路的设计

为了实现封堵器海洋工作环境中的无线遥控动作,封堵器在海底工作中采用了水声通信技术.文章首先介绍了水声通信系统的整体设计.在前期工作中,从影响水声通信的因素出发,对水声通讯频率的选择及水声换能器的选型进行了研究,确定了水声通讯的载波频率.在此基础上提出了基于单片机的水声Modem的制作方案,设计了单片机系统电路.并对单片...     

VLSI design investigation for low-cost, low-power FFT/IFFT processing in advanced VDSL transceivers

The problem of an efficient very large scale integration (VLSI) realization of the direct/inverse fast Fourier transform (FFT/IFFT) for digital subscriber line (DSL) applications is addressed in this paper. The design of scalable and very high-rate (VDSL) modem claims for large and high-throughput complex FFT computations while for massive and fast deployment of the xDSL family low-cost and low-power constraints are key issues. Throughout the paper we explore the design space at different levels (algorithm, arithmetic accuracy, architecture, technology) to achieve the best trade-off between processing performance, hardware complexity and power consumption. A programmable VLSI processor based on a FFT/IFFT cascade architecture plus pre/post-processing stages is discussed and characterized from the high-level choices down to the gate-level synthesis. Furthermore low-power design techniques, based on clock gating and data driven switching activity reduction, are used to decrease the power consumption exploiting the correlation of the FFT/IFFT coefficients and the statistics of the input signals. To this aim both frequency-division and time-division duplex schemes have been considered. The effects of supply voltage scaling and its consequence on circuit performance are examined in detail, as well as the use of different target technologies. Synthesis results for a 0.18 μm CMOS standard-cells technology show that the processor is suitable for real-time modulation and demodulation in scalable full-rate VDSL modem (64-4096 complex FFT, 20 Msample/s) with a power consumption of few tens of mW. These performances are very interesting when compared to state-of-the-art software implementations and custom VLSI ones.     

Implementing polarization shift keying over satellite – system design and measurement results

Polarization shift keying (PolSK) is a digital modulation technique using the state of polarization of an electromagnetic wave as the signalling quantity. PolSK comes from fibre communications, where the channel offers two orthogonal states of polarization. This article develops on the idea to adapt this technology to satellite communications, where similar channel conditions exist. For this purpose, a digital PolSK modem was implemented on a programmable logic board. A proposal for constellation design as well as thoughts on synchronization of PolSK over satellite is presented. The modem was used to demonstrate a 16‐state Polarization Shift Keying link over a commercial satellite in K_u band. Measurements have been conducted in a back‐to‐back setup on intermediate frequency and on a K_u band transponder simulator to assess the impact of path‐length differences, carrier recovery and non‐linearity. Copyright © 2015 John Wiley & Sons, Ltd.     

白酒香气鉴评的传统方法和现代手段研究

介绍了多种针对白酒气味的研究方法,既包括传统感官方法也包含现代科技手段,并且对这些方法进行一定分析,以期促使其在白酒气味的研究领域上起到更大作用。