基于双层角色和组织的可扩展访问控制模型

针对现有基于角色的访问控制(RBAC)研究存在角色设置单一使得适应性差、多域环境下角色或权限冗余、对资源管理关注不够等问题,论文提出支持资源管理的基于双层角色和组织的访问控制模型。通过双层角色划分,提出基于职能角色和任务角色的双层角色架构,使得模型更加符合实际,也更具适应性;引入组织的概念并与双层角色相结合,对角色和权限的概念加以扩展,形式化定义了提出的基于双层角色和组织的访问控制模型,描述了影响模型安全的职责分离约束和势约束。对模型的表达能力、复杂度进行了分析,分析表明该机制不仅保留了RBAC的特点与优势,且比RBAC具有较低的复杂度并更适合于由多个相似组织构成的分布式多域环境。     

一种基于扩展角色的访问控制模型和方法

针对传统的基于角色访问控制（RBAC）模型的不足,在基于角色的权限访问控制的基础上,提出了一个扩展角色访问控制模型,新模型对角色和权限的概念进行了扩展,使得RBAC模型能够更灵活、高效地对系统进行权限访问控制,增强了访问控制安全。     

WSRBAC在管理信息系统中的应用

基于角色的访问控制(RBAC)模型是一种有效但比较被动的访问控制模型,不能对主体所拥有的权限进行动态管理,面向工作流和服务的RBAC(WSRBAC)模型基于RBAC但更为有效。论文介绍了WSRBAC相关的基本概念,阐述了WSRBAC的访问控制规则,给出了一种形式化的描述,结合某数控设备开发实例,实现了WSRBAC在企业管理信息系统中的设计和应用。     

基于角色的跨域使用控制模型及其应用研究

针对网络环境下多自治域之间互操作安全需求,提出了一个基于角色和映射规则的跨域使用控制模型CD_UCON(Cross-Domain UCON)。该模型结合了基于角色的访问控制(RBAC)模型的权限机制和使用控制模型(UCON)的框架。为实现属性易变性和访问控制连续性,CD_UCON对UCON模型中的属性和授权规则进行扩展;通过映射规则实现跨域交互。以CD_UCON模型在物资采购管理系统中的应用分析说明了该模型的可行性。     

基于角色访问控制机制在Web信息系统中的应用

基于角色访问控制(RBAC)是一种方便、安全、高效的访问控制机制和重要的信息安全技术,他在满足企业信息系统安全需求方面显示了极大的优势。对RBAC模型——NRBAC模型进行了深入的研究,针对Web信息系统的结构特征及其对安全访问控制的要求,提出NRBAC模型的实现方案,从而利用基于角色访问控制技术实现系统的权限管理功能。     

RBAC与MAC在多级关系数据库中的综合模型

多级安全数据库的安全策略需要各种模型来表达,访问控制模型是其中之一.强制访问控制(MAC)模型保证多级数据库中的信息流动符合系统的安全策略.利用基于角色的访问控制(RBAC)来实现MAC能方便多级安全数据库的权限管理.提出了一种MAC与RBAC的综合模型,定义了多级角色与内部角色的概念,并给出了综合模型中经过修改后的操作,使得系统能自动地完成符合强制访问控制策略的用户权限的管理.该模型方便了管理员的权限管理,适合用户较多,安全层次比较复杂的多级关系数据库系统.最后给出了模型的部分实现机制.     

角色访问控制在协同环境中的扩展

信息安全技术领域一个非常重要的方面是访问控制。在大型的分布式协同系统中,用户与角色的数量众多,关系复杂,RBAC模型存在一定的局限性。以基于角色的访问控制模型为基础,针对分布式协同环境下的特征,将RBAC在分布式协同环境下进行了扩展,提出一种利用角色互斥的方法来实现职责分离原则,将角色互斥分为静态和动态互斥并给出形式化描述,使得扩展后的模型在权限方面提高了安全性。     

基于角色的管理信息系统安全机制的研究与设计

针对现有管理信息系统的安全问题，介绍了基于角色的安全访问控制RBAC基本模型。该模型形式化的描述了用户、角色、操作许可之间的关系。此外，通过分析某大型企业管理信息系统的特征以及企业对信息安全访问控制的具体要求，提出了基于角色的安全机制设计方案。此方案具有较大的灵活性，使系统的安全性得到提高，并能够简化授权管理。     

改进的RBAC模型在大型OA系统中的应用

基于某研究所的大型OA系统安全访问控制的实际需求,分析了传统的RBAC模型所存在的问题,提出一种改进的RBAC模型,该模型中引入用户组进行了改进,增加了用户组对数据资源的授权,使用户的权限变为功能权限和资源权限之和,定义了访问规则,对特定的IP和用户的角色激活时间加以控制,采用独立的安全审计,对用户的每个角色的操作和超级管理员的操作进行审计,防止非法操作和滥用权力,在实际OA项目中应用时,该模型安全有效,并且适用于同类大型系统。     

基于XACML的RBAC模型的研究与应用

RBAC（Role Based Access Control基于角色的访问控制）模型作为访问控制系统中的理想选择。近年来得到了广泛的研究。本文针对规模较大的访问系统的特点。提出一种改进的基于XACML的访问控制模型,使得RBAC模型具有了良好的灵活性、扩展性、以及跨平台性,并将该模型在大型互动网络游戏开发平台中进行了验证。     

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.     

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.     

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.     

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.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

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.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.