基于角色授权的Web service访问控制模型

访问控制是一种实现信息安全的有效措施,可防止对资源的未授权访问.针对目前Web服务本身的安全控制不能很好地适应企业级用户的安全需求这一问题,构造了一种基于角色授权的Web服务访问控制模型.该模型将权限同角色联系起来,根据服务特征及访问状态给用户赋予不同的角色,用户通过得到的相应角色获得访问权限,从而实现对服务本身的保护,防止未授权用户获取 服务信息.另外文中还讨论了该模型实现中的几个关键问题.     

RBAC优化模型在嵌入式Web系统中的应用研究

针对嵌入式Web应用系统的自身安全,结合嵌入式Web应用系统的自身特点,通过分析现有基于角色的访问控制模型的不足,提出了一种改进的RBAC模型。通过引入用户组和部门概念,对RBAC模型进行了重新描述和形式化定义。通过优化,将用户实体之间的关系理顺,利用对用户分组,更进一步降低授权管理的复杂度,减少授权管理中的失误,使其能够更加符合实际应用中的需求。同时,在此访问控制模型的基础上,实现嵌入式Web应用系统的访问控制功能,并对实现的Web应用系统进行测试,以验证访问控制方案的性能。     

利用RBAC机制实现WWW环境中的安全访问控制

提出了一种基于WWW的扩展RBAC模型，在用户和角色之间增加角色代理层，由客户端完成代理角色的功能，实现角色的动态分配和解决网络传输瓶颈问题，克服了标准的基于角色的访问控制模型应用于WWW环境的缺陷，并探讨了以这种扩展RBAC模型为基础的互联网环境下的安全访问控制的实现，这种安全访问控制方案能较好地适用于基于Web的应用系统。     

基于命令模式的权限控制的设计与实现

针对Web系统的特点及其对用户访问控制的特殊要求,笔者在RBAC（基于角色的访问控制）模型的基础上引入了命令模式,设计并实现了分级的、细粒度的权限管理子系统.基于设计模式中的命令模式,利用方法调用与方法执行分离的原则和采用集中调度控制所有方法执行的方式,设计出一种灵活的权限控制管理.实践证明此方案不仅可以满足大中型Web系统对权限管理的需求,而且能随组织结构或安全需求的变化而变化,具有很好的灵活性和可操作性.     

Web服务中的基于快速信任的访问控制模型

OASIS的WEB服务安全规范，不提供信任评估和授权决策的支持。文中针对于Web服务下，虚拟临时组织中的访问控制和授权，设计了一种基于怏速信任的访问控制模型（WS—STBAC，SwiftTrust—Based Access Control for Web Service），一种与认证中心相类似的中间件。WS—STBAC南策略管理、信任度计算和授权决策3个模块组成。在获得提供方的访问控制策略和信任计算所需的数据和算法之后，WS—STBAC计算对请求方的信任度。并根据访问控制策略，代替服务提供方进行授权决策。     

基于安全性规范与RBAC模型的Web Service安全框架研究

基于WS-Security规范和基于角色的访问控制模型提出一种灵活、可扩展的Web服务安全通信框架WsSF,并选择基于角色的访问控制模型RBAC作为Web Service访问控制的基础模型,建立了基于Web服务的RBAC模型,可为Web Service安全实践提供参考。     

利用属性证书实现Web资源的角色访问控制

针对目前Web资源访问控制过程中存在的问题，提出了利用属性证书实现Web的角色访问控制方法。同时通过用户、角色和权限之间的关系，给出了属性证书的应用方案，详细分析了其实现过程、属性证书的验证过程和用户角色的层次关系，最后分析总结了利用属性证书实现基于角色的访问控制的应用特点。     

基于Web Service的访问控制供应的研究

针对目前多个应用系统对共享的访问控制系统的需求,结合Web Service服务环境特点及关注点分离思想,提出一种基于Web Service的访问控制供应结构,给出访问控制供应服务订阅,访问控制判定实现过程,解决了各领域重复开发访问控制系统及访问控制供应的问题,实现应用系统与访问控制供应的柔性连接。     

基于角色和Web Service的访问控制方法应用研究

利用角色访问控制技术可以有效地实现用户访问权限的动态管理，而Web Service提供的高度互操作性和易访问性能够很好地完成对用户权限的验证。本文通过对访问控制技术的比较研究，介绍了如何利用Web Service和基于角色访问控制原理实现多级角色访问控制的策略和方法。     

多域应用安全互操作的授权模型

讨论了基于角色的访问控制策略在多域安全应用中的互操作问题，提出了多域应用环境下角色映射的概念，建立了一个基于角色的组合层次关系的多域授权管理模型，通过约束条件和授权步给出了跨域用户的授权访问控制策略，实现了多域环境的安全互操作．该模型不仅使授权机制易于实现，而且可以灵活地适应应用中安全需求的变化。     

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