Diameter协议对RADIUS协议性能缺陷的改进

Diameter协议是下一代AAA协议,他将在未来取代RADIUS协议并在无线网络中发挥自己的优势。介绍了Diameter协议和RADIUS协议两种协议,分析了两者诸多性能的差异,着重指出了Diameter协议相对于RADIUS协议的优势和改进方案,最后对Diameter协议在未来无线网络中的应用做出了展望。     

AAA协议在电信业务中的演进和典型应用

分别讨论RADIUS(远程鉴权拨入用户服务)与Diameter两个协议,结合其在WLAN(无线局域网)、未来EPC(演进分组核心网)及IMS(IP多媒体子系统)中的运营,重点分析这两个AAA(鉴权、授权、计费)协议在电信业务中的典型应用。文章认为,Diameter使用节点发现机制和更安全有效的转发系统,比RADIUS更加安全且更具扩展性,可以对未来EPC和IMS的AAA需求提供更好的支持。     

Diameter协议的实现——Opendiameter软件体系结构分析

Diameter协议是IETF的AAA(认证、授权、记费)工作组针对RADIUS协议的不足,提出的下一代AAA协议,设计之初就充分考虑了可扩展性、移动性和安全性,必将在移动IP尤其是MIPv6中得到广泛应用。Opendiameter是IETF组织人员开发的开源软件,实现了Diameter协议,并为进一步的开发提供了API(应用编程接口)。文中描述了Diameter基础协议和部分应用协议,并在此基础上,重点分析了Opendiameter的体系结构、线程观、基本信息处理和提供的C API。     

Diameter协议及应用

介绍了Diameter协议、Diameter功能实体,并将Diameter协议与RADIUS协议进行了比较,最后介绍了Diameter协议在不同网络环境中的应用情况。     

基于EAP/RADIUS的移动IPv6接入认证研究

对可扩展认证协议(EAP)和远程用户拨入认证系统(RADIUS)协议进行了阐述,给出了基于移动IPv6的AAA(认证、授权、计费)体系架构。针对移动IPv6移动用户接入认证问题,提出了基于EAP/RADIUS的移动IPv6接入认证构架,通过EAP与RADIUS服务器协作的方式实现对移动用户的接入认证。     

Diameter扩展协议在IMS中的应用分析

IP多媒体子系统(IMS)采用Diameter协议实现网络认证、授权和计费的功能.Diameter协议包括基础协议和扩展应用协议两部分.文章主要分析IMS中的Diameter SIP应用和Diameter信用控制应用两种扩展应用协议,重点探讨如何应用Di-ameter扩展协议进行IMS的认证、授权和在线计费的问题.     

新—代的AAA协议——Diameter

本首先介绍了鉴别，授权，计费协议的概念，并指出其在移动通信系统中的地位和作用。接着分析了目前最常用的认证计费协议——RADIUS，分析了该协议的优点和缺陷。针对RADIUS的不足之处，本引入了它的升级版本——DIameter协议。在全面介绍Diameter协议的基础上，重点描述了在Diameter协议的MIP应用中一个用户终端如何完成一次完整的认证。最后指出在未来移动通信网逐渐向全IP过渡的情况下。Diameter协议必将得到广泛的应用。     

移动IP与SIP集成应用中优化的AAA过程

在移动IP和SIP分别实现网络层和应用层移动性管理的多层多协议移动性管理方案中,当两种协议独立进行AAA操作时,存在缺乏效率的问题。为解决该问题,提出优化方案——“移动IP与SIP集成应用中优化的AAA过程”(OAPIMS)。在新一代AAA协议Diameter环境下,通过移动注册时,对两种协议的操作信令进行优化,减少了信令交互次数,达到提高效率的目的。分析表明,该方法可以明显降低信令开销,减少时延,提高系统性能。     

Diameter协议及其在移动流媒体计费中的应用

Diameter协议是新一代AAA服务协议标准.本文介绍了Diameter协议的特性和优势,并根据Diameter协议的计费功能介绍了其在流媒体计费中的应用.     

Mobile IP系统中的AAA接口研究与设计

在全IP无线互联网包分多址(PDMA)系统中,移动用户可以通过简单IP或移动IP两种接入方式接入Internet。如何对以上两种接入方式的用户提供基于RADIUS协议的身份认证、授权及基于流量方式的计费功能,是PDMA系统面临的一个重要问题。文章提出了支持微移动和宏移动两层协议体系分别进行AAA机制处理,以及两层AAA机制间有效协调的设计方案,在某地试验网的实际运行中取得了良好的效果。     

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.     

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.     

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.