网络病毒危害与攻防技术分析

网络病毒威胁威胁着每个网络用户,网络黑客可以通过传播病毒获取用户隐私,窃取用户财产.要给网络用户安全的使用环境,就要对网络病毒进行合理防御与查杀.这就需要对网络病毒生成的原理,网络病毒的特征有所了解,有的放矢采取合理技术手段加以防御与清除.本文就网络病毒的特性进行了分析,针对特性就如何防御提出了可行性的建议.     

企业网络中常见攻击事件和病毒的分析

通过对企业网络中常见攻击事件、病毒的分析,有助于我们提高网络安全意识,提高网络安全防御的能力,防患于未然,更好地保障企业网络健康平稳运行。     

网络病毒防御的解决方案

随着网络化应用程度的提高,能否有效防御网络病毒已决定着网络技术进一步应用的前景。本文介绍了网络各个环节上的病毒防御方式,并分析不同网络环境下防毒技术的选择。     

数据挖掘在计算机网络病毒防御中的应用

互联网信息时代已经来临,网络病毒也在肆虐,计算机的网络系统容易受到攻击和破坏,网络病毒威胁着网络用户的使用安全,文章通过对数据挖掘在计算机中的病毒防御进行探讨和研究,将网络病毒扼杀在摇篮之中,有效的打击网络病毒的方式方法都需要探索。     

基于数据挖掘技术的计算机网络病毒防御系统设计

随着我国现代社会的发展,计算机技术的应用也越来越广泛,在网络技术逐渐普及的今天,相关的计算机网络病毒也在不断地出现,这些病毒往往通过网络系统的漏洞如今计算机系统,并对系统中的数据信息进行破坏和恶意篡改。为了更好的防御计算机网络病毒带来的危害,相关的数据挖掘技术由此应运而生。本文将针对计算机网络病毒的类型展开讨论,并对基于数据挖掘技术的计算机网络病毒防御系统进行相关的探讨。     

网络型病毒与网络安全防御研究

在信息时代下,人们的工作方式、生活方式、思维方式都随着网络技术的进步而改变。此时,网络安全防御成为了社会上广泛关注的话题。目前,网络型病毒成为了最大的阻碍。一般而言,网络型病毒都是突然发生的,且传播的路径非常多样化,经常导致大面积的网络瘫痪。网络安全防御在近几年虽然投入了较大的研究力度,可最终的成果并不理想。部分网络安全防御的软件或者程序,的确效果突出,但价格过高,不符合大众消费的理念。所以,绝大多数地区的网络,仍然是面对网络型病毒的威胁。日后,必须采取有效的防御策略来应对。     

2016年“攻防”大战:安全厂商亮出新招数

安全威胁不断增多、病毒攻击呈多样化态势、用户安全意识薄弱、自主创新不足、安全能力不够……这些问题导致我国2016年网络安全形势依然严峻.对此,安全企业计划如何布局加以应对呢? 山石网科:转向“主动”防御 在网络安全防御工作上,山石网科总裁兼CEO罗东平认为,业界需要从“被动”转向“主动”,从“防御”转为“预警”,彻底转换长久以来形成的“固守型”网络安全思维,树立以行为分析为基础的智能安全理念.“利用‘发现、可视、控制一体化’的安全思维模式,应对高级威胁和未知威胁.”     

开放网络环境下隐私数据安全防御模型研究

针对传统模型在开放网络环境下对隐私数据安全防御效果比较差,当应对多种网络攻击时,模型的防御响应时间比较长,为此提出开放网络环境下隐私数据安全防御模型研究。利用Spring架构建立开放网络环境下隐私数据安全防御模型框架,包含网络信息采集层、分析层、预警层以及安全防御层四个功能层次;利用入侵感知算法对网络流量数据进行计算,分析开放网络环境下隐私数据安全状态。利用预警规则确定隐私数据安全预警等级,驱动隐私数据安全防御措施。设立网络边界安全机制,对非法入侵数据包和病毒进行拦截。利用加密算法对隐私数据进行加密防御,以此实现开放网络环境下隐私数据安全防御模型建立。经实验证明,设计模型防御响应时间短于传统模型,具有良好的应用前景。     

病毒防御机制综述

病毒的多样性,病毒入侵手段的多样性使得病毒防御已经不是单一技术手段可以实现的目标,本文讨论了基于主机和网络的多种病毒防御机制。     

网络节点增减下的潜伏型病毒传播行为建模研究

研究潜伏型网络病毒的传播行为有助于预先设计合理的防御策略,防止病毒传播对网络造成危害,维护网络的安全.本文以潜伏型病毒传播行为为基础,综合考虑病毒传播存在潜伏期的特点以及网络节点增加与移除的情况,构建了节点增减条件下含时滞项的潜伏型病毒传播模型,用以探索网络节点增减条件下病毒潜伏期τ对病毒传播分岔行为的影响.此外,本文...     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

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.