Intranet安全与防火墙技术研究

针对Ｉｎｔｒａｎｅｔ上的安全问题,在分析现有的几种防火墙技术的结构和特点的基础上,讨论了Ｋｅｒｂｅｒｏｓ身份认证协议,提出了一种结合Ｋｅｒｂｅｒｏｓ身份认证的防火墙结构。     

网络信息交换的OTP认证技术

在开发防火墙系统以及实现防火墙与内部网络安全管理子系统之间的数据交换时,要用到身份认证和加密技术,本文主要介绍了用OTP机制实现,身份认证,为了保证信息的安全性,还介绍了实现初始密钥交换和数据加密技术,最后给出了简单的结论。     

一种将认证中心与业务系统整合方案

身份认证是保障业务系统安全的防火墙。使用CA认证中心虽然可以大大提高业务系统的安全性,但是采用第三方CA认证中心,需要很大一笔费用。市场上业务系统的开发成本往往很低,使用第三方CA身份认证来保证系统的安全性是不切实际的。针对这种情况,设计出一种适合开发成本低的业务系统的CA身份认证方案,用开源的EJBCA实现第三方CA认证中心的功能;使用EJBCA的Web Service服务,实现业务系统与EJBCA之间的信息交互及身份认证。这样,既可以保障业务系统的安全性,又可以大大缩减开发成本。     

Internet／Intranet环境下的交互式强用户认证系统

企业需要在Ｉｎｔｅｒｎｅ／Ｉｎｔｒａｎｅｔ环境下安全从事商务活动,用户认证是确保其安全性的基本前提,笔者通过对现有用户认证方法和协议的研究,在Ｋｅｒｂｅｒｏｓ协议的基础上,提出了一种基于数字证书与灵巧卡的、采用公钥密码体制的交互式强用户认证系统。该系统在满足交互式实时认证的速度要求的前提下,简化了密钥的管理、分配、存贮问题,也减轻了客户端的负担。较好地解决了Ｋｅｒｂｅｒｏｓ协议存在的几个不足。     

基于CORBA的分布式系统安全防范

在提出CORBA分布式系统基本模型的基础上 ,从防火墙技术、数据加密技术和身份认证 3个方面阐述了基于CORBA的分布式系统安全防范措施的设置 .     

浅议电子政务的若干安全技术

介绍和比较了电子政务实施中针对网络安全所采用的若干关键技术的优势和缺陷，包括网络防火墙技术、数据加密技术和身份认证体制。     

信息系统的安全体系结构分析与设计

分析了构成经济信息系统安全体系的要素,提出系统容错、病毒防范、防火墙、访问控制、身份认证、数据加密和应用审计等安全防范措施。     

基于应用层代理技术的无线网络软交换方案

在无线网络环境下,网络应用层提供授权检查及代理服务。当外部某台主机试图访问受保护网络时,必须先在防火墙上经过身份认证。应用代理技术的优点是既可以隐藏内部IP地址,也可以给单个用户授权,即使攻击者盗用了一个合法的IP地址,也通不过严格的身份认证。因此应用网关比报文过滤具有更高的安全性。     

部队网络安全解决方案

从安全性方面入手,提出了采用防火墙技术、NAT技术、VPN技术、网络加密技术、身份认证技术、入侵检测技术、多层次多级别的防病毒系统等构筑网络安全防御系统,解决部队网络安全问题。     

基于PCI总线接口卡的身份认证

目前主要采用的身份认证方法有两种,即静态身份认证和动态身份认证.本文介绍了动态身份认证的两种方法:时间同步机制的身份认证和挑战/应答机制的身份证证,并介绍了采用PCI接口卡实现挑战/应答机制的身份认证方案,阐述了制作PCI接口卡及采用PCI9052接口芯片开发PCI总线驱动程序的方法和编程注意要点.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that