干涉检测数据抗振动影响的方法研究

在光学元件的抛光阶段,通常采用干涉仪检测光学元件的面形数据,对加工工作提供指导意见。移相干涉术易受环境振动的干扰,获得的波前相位的干涉图信息不完整,难以准确给出光学元件表面的干涉数据。为了利用干涉仪检测数据给出被测光学元件面形上的各点准确数据,采用等精度测量消除随机误差的方法,对多次检测数据求取平均值以获取被测光学元件面形的准确数据。针对一块Φ1200mm口径的圆形光学元件的实验表明这种方法可以较为有效地消除检测中振动因素的影响。     

基于模数的干涉相位自适应中值滤波法

为了改善对干涉相位噪声的抑制效果而又确保有用相位跳变信息不被滤除,该文首先研究了模数滤波算法,并提出了一种基于最短子区间搜索的干涉相位模数估计算子对其进行改进,在进一步分析模数估计参数与相位分辨率之间关系的基础上,提出了一种局部相位中心随干涉相位质量自适应变化的中值滤波方法。该方法不仅克服了模数滤波导致的条纹边缘模糊问题,还解决了传统空域滤波进行一致性处理所造成的过滤波和欠滤波问题,而且具有较高的运算效率。最后通过对仿真和实测TerraSAR–X数据的处理和分析,验证了该方法的有效性。     

基于离轴显微干涉术的单幅干涉图相位求解（英文）

提出一种用于测量微结构表面形貌的离轴显微干涉术。该技术的实验装置为一个优化的马赫-曾德尔干涉仪。其特点为参考波是具有一定载频的倾斜波。该技术中应用CCD记录离轴显微干涉图,并用傅里叶变换方法对记录的干涉图在傅里叶面进行频谱滤波求解相位。不同于经典显微干涉术,离轴显微干涉图的载频较高,仅需单幅干涉图即可得到相位信息。因此该技术在测量中具有防振、快捷有效的特点。利用一个标准微台阶以及微孔阵列的形貌检测结果验证该技术的有效性,同时与轮廓仪的测试结果进行对比,证明结果一致。被测物也应用Mirau干涉显微镜进行测试,实验结果表明经典显微干涉图干涉信息载频不足,仅使用单幅干涉图不能得到正确相位,该组实验证明了离轴显微干涉术相对于传统显微干涉术的优越性。     

用于圆形口径光学元件的功率谱密度检测

光学元件加工质量的检测和评价是保证整个光学系统安全、正常运行的关键.波前功率谱密度(Power Spectral Density,PSD)能给出光学表面的空间频谱分布,反映高精度光学元件加工质量的特殊要求.在总结现有功率谱密度指标基础上,提出由于圆形口径的旋转对称性,可以采用径向波前功率谱密度来表征圆形口径光学元件波前频谱分布特征的方法,并给出了采用三坐标仪作为测试仪器测量圆形口径光学元件的波前功率谱密度时相应的数值计算方法.     

利用声光调制器进行错位外差干涉测量

一、前言 外差干涉测量法能测量高精密透镜象差,表面形状和形变、振幅、速度等。其频率彼此靠扰的波前相干涉而产生一电差频信号,差频信号的相位与两波前之间的光程差成正比。山于信号相位与参考信号同步,因而测量精度约为2π/100rad。可用移动光栅、旋转波片或超声光调制器作为频移器件。 利用光栅的错位干涉测量法已在Ronchi试验中用于测量透镜象差。现在又提出了错位外差干涉测量法,它利用移动光栅使待测波前产生频移和空间错位。这些错位外差干涉计用于自适应光学元件中的波前校正和镜面的形状测量。     

单幅干涉条纹图的高精度波面重建技术

结合莫尔条纹、傅里叶变换和数字相移技术实现了对单幅干涉条纹图的高精度相位计算和波面重建.首先,用计算机生成与被处理干涉条纹频率相近的数字相移条纹图,与实际干涉条纹图叠加得到相移莫尔条纹图;然后,利用傅里叶变换、双频滤波、傅里叶反变换和相移技术得到干涉条纹图的相位数据;最后利用波面拟合技术重构原干涉条纹图对应的波面形状.研究结果表明,该技术不仅消除了干涉仪硬件相移产生的非线性误差和滤波时的频谱移中误差,高精度获得了单幅干涉条纹图对应的波前,而且简化了系统的机械结构.同时,对环境的要求明显降低,特别适用于生产现场的检测.     

基于光学干涉法的光学元件表面粗糙度检测技术

为实现光学元件表面微小粗糙度的精准、详细检测,研究基于光学干涉法的光学元件表面粗糙度检测技术。该技术采用基于集成光学干涉成像技术对光学元件表面干涉成像,通过改进的Niblack二值化算法提取元件表面干涉图像条纹信息,并基于节点迭代的去毛刺方法细化处理干涉条纹,利用最小二乘方法拟合干涉条纹,获取最小二乘拟合直线得出评定基准,建立评定表面粗糙度的高度参数和间距参数的数学模型,完成粗糙度检测。测试结果显示:该技术干涉成像能力较强,生成的光学透镜元件干涉图像弧度与边缘较为清晰,可有效去除干涉条纹毛刺,检测光学元件表面粗糙度时的真正类率最大数值已达到1.0。     

专利

美国加州Hughes Electronics公司的A.A.Betin等人提出一种环路4波混合相位共轭反射镜的设计方案。小型环路相位共轭器是由一个非线性元件、光电二极管和光学增益介质组成。非线性元件前表面透射光,后表面反射光。在前表面和后表面之间是非线性光学介质,信号光束入     

基于相位测量法测量透射式相位光栅的表面形貌

建立了一套基于马赫-曾德尔干涉仪的测量系统,获得了透射式相位光栅的相位信息并推算出光栅的表面形貌。给出了相位测量法的基本原理,运用傅里叶变换法和相位解包裹技术,对实验系统采集的干涉图的相位信息进行处理并计算出光栅的高度、周期和底角等结构参数。结果表明,该测量方法和系统能够精确地测量光学相位元件的表面形貌,具有较高的实用价值。     

宽光谱范围干涉检验术

点衍射干涉仪的一种新技巧可使劳仑斯·伯克利实验室X射线光学中心的研究人员在可见光到X射线波长的宽光谱范围里精确测量光学元件。对简单系统所作的试验已显示非常优良的可重夏性。在普通点衍射干涉仪中，针孔由于使相干照明衍射成球面参考波前（图1），消除了参考表面的需要。含有针孔的半透明拥模安装在待检光学元件焦点附近。直接通过该针孔膜的光对检验光学元件照明，产生检验波前，该波前又与球面参考波前干涉。以后的条纹分析给出了有关检验表面质量的信息。这种普通设计有两个特有缺点。产生的参考波前的针孔限制了参考波强度，这…     

Alternative Schemes for Dynamic Secure VPN Deployment in UMTS

Three alternative schemes for secure Virtual Private Network (VPN) deployment over the Universal Mobile Telecommunication System (UMTS) are proposed and analyzed. The proposed schemes enable a mobile node to voluntarily establish an IPsec-based secure channel to a private network. The alternative schemes differ in the location where the IPsec functionality is placed within the UMTS network architecture (mobile node, access network, and UMTS network border), depending on the employed security model, and whether data in transit are ever in clear-text, or available to be tapped by outsiders. The provided levels of privacy in the deployed VPN schemes, as well as the employed authentication models are examined. An analysis in terms of cost, complexity, and performance overhead that each method imposes to the underlying network architecture, as well as to the mobile devices is presented. The level of system reliability and scalability in granting security services is presented. The VPN management, usability, and trusted relations, as well as their behavior when a mobile user moves are analyzed. The use of special applications that require access to encapsulated data traffic is explored. Finally, an overall comparison of the proposed schemes from the security and operation point of view summarizes their relative performance. Christos Xenakis received his B.Sc. degree in computer science in 1993 and his M.Sc. degree in telecommunication and computer networks in 1996, both from the Department of Informatics and Telecommunications, University of Athens, Greece. In 2004 he received his Ph.D. from the University of Athens (Department of Informatics and Telecommunications). From 1998–2000 was with the Greek telecoms system development firm Teletel S.A., where was involved in the design and development of advanced telecommunications subsystems for ISDN, ATM, GSM, and GPRS. Since 1996 he has been a member of the Communication Networks Laboratory of the University of Athens. He has participated in numerous projects realized in the context of EU Programs (ACTS, ESPRIT, IST). His research interests are in the field of mobile/wireless networks, security and distributed network management. He is the author of over 15 papers in the above areas. Lazaros Merakos received the Diploma in electrical and mechanical engineering from the National Technical University of Athens, Greece, in 1978, and the M.S. and Ph.D. degrees in electrical engineering from the State University of New York, Buffalo, in 1981 and 1984, respectively. From 1983 to 1986, he was on the faculty of Electrical Engineering and Computer Science at the University of Connecticut, Storrs. From 1986 to 1994 he was on the faculty of the Electrical and Computer Engineering Department at Northeastern University, Boston, MA. During the period 1993–1994 he served as Director of the Communications and Digital Processing Research Center at Northeastern University. During the summers of 1990 and 1991, he was a Visiting Scientist at the IBM T. J. Watson Research Center, Yorktown Heights, NY. In 1994, he joined the faculty of the University of Athens, Athens, Greece, where he is presently a Professor in the Department of Informatics and Telecommunications, and Director of the Communication Networks Laboratory (UoA-CNL) and the Networks Operations and Management Center. His research interests are in the design and performance analysis of broadband networks, and wireless/mobile communication systems and services. He has authored more than 150 papers in the above areas. Since 1995, he is leading the research activities of UoA-CNL in the area of mobile communications, in the framework of the Advanced Communication Technologies & Services (ACTS) and Information Society Technologies (IST) programmes funded by the European Union (projects RAINBOW, Magic WAND, WINE, MOBIVAS, POLOS, ANWIRE). He is chairman of the board of the Greek Universities Network, the Greek Schools Network, and member of the board of the Greek Research Network. In 1994, he received the Guanella Award for the Best Paper presented at the International Zurich Seminar on Mobile Communications.     

高速光纤综合通信网络平台研究

现代通信网络应能满足各种通信业务和通信容量日益发展的需求,实现话音、数据、视频、IP等业务的一体化综合交换和传输。在比较TDM、IP和ATM三种协议的基础上,提出"采用内置RPR和MPLS功能的MSTP平台"建设光纤综合通信网络平台的实现方法。MSTP采用SDH的数据帧结构,保持了SDH标准光接口、灵活分插低速信号、自愈环保护和功能强大的网管等优点,可对TDM、IP和ATM协议进行优化传输。     

1-V bulk-driven CMOS analog programmable winner-takes-all circuit

In this paper, a 1-V bulk-driven analog winner-takes-all circuit with programmable k-winners capability is proposed. By presetting a set of binary bits, the desired k-winners-take-all or k-losers-take-all function is programmable. The proposed upward-and-downward searching greatly improves the response time. The chip has been fabricated with a 0.25-μm CMOS technology. Simulated results show that the response time of the winner-takes-all circuit is 50 μs under 5-mV identified resolution. The input range is approximately to be rail-to-rail. This work was in part supported by the Chip Implementation Center and the MOE Program of Promoting Academic Excellence of Universities under the Grant EX-93-E-FA09-5-4. Yu-Cherng Hung was born in Changhua, Taiwan, R.O.C., in 1964. He received the M. S. degree in electronics engineering from the National Chiao Tung University, Hsinchu, Taiwan, R.O.C., in 1992, and the Ph.D. degree in electrical engineering from National Cheng Kung University, Tainan, Taiwan, R.O.C., in 2004. From Dec. 1986 to Jan. 2005, he was with the Division of Computer/Information, Chinese Petroleum Corp., Taiwan. He is currently an Assistant Professor with the Department of Electronic Engineering, National Chin-Yi Institute of Technology, Taiwan, R.O.C. His main research interests include analog circuit design, low-voltage VLSI design, and neural network applications. Dr. Hung is a Member of Phi Tau Phi Honorary Scholastic Society, IEEE, and the Institute of Electronics, Information, and Communications Engineers (IEICE). Bin-Da Liu received the Ph.D. degrees in electrical engineering from the National Cheng Kung University, Tainan, Taiwan, R.O.C., in 1983. Since 1977, he has been on the faculty of the National Cheng Kung University, where he is currently a Distinguished Professor in the Department of Electrical Engineering and the Director of the SoC Research Center. During 1983–1984, he was a Visiting Assistant Professor in the Department of Computer Science, University of Illinois at Urbana-Champaign. During 1988–1992, he was the Director of Electrical Laboratories, National Cheng Kung University. He was the Associate Chair of the Electrical Engineering Department during 1996–1999 and the Chair during 1999–2002. Since 1995, he has been a Consultant of the Chip Implementation Center, National Applied Research Laboratories, Hsinchu, Taiwan. He has published more than 200 technical papers. He also contributed chapters in the book Neural Networks and Systolic Array Design (D. Zhang Ed. Singapore: World Scientific, 2002) and the book Accuracy Improvements in Linguistic Fuzzy Modeling (J. Casillas, O. Cordón, F. Herrera, and L. Magdalena Eds. Heidelberg, Germany: Springer-Verlag, 2003). His current research interests include low power circuit, neural network circuit, CMAC neural network, analog neural network architecture, design of programmable cellular neural networks, and very large-scale integration implementation of fuzzy/neural circuits and audio/video signal processors. Dr. Liu is a Fellow of IEEE and the Vice President of Region 10, IEEE Circuits and Systems Society. He served as a CAS Associate Editor of IEEE Circuits and Devices Magazine and an Associate Editor of IEEE Transactions on Circuits and Systems I: Regular Papers. He is serving as an Associate Editor of IEEE Transactions on Very Large Scale Integration (VLSI) Systems. Chung-Yang Tsai was born in Mian-Li, Taiwan, R.O.C. He received the B.S. and M.S. degrees both in electrical engineering from the National Cheng Kung University, Tainan, Taiwan, R.O.C., in 2001 and 2003, respectively. His research interests include very large-scale integration design and signal processing.     

On Fixed-Mobile Network Convergence

As the convergence in digital industry takes shape, the digital networks, both wireline and wireless, are also converging to offer seamless services and enhanced experience to the user. With the arrival of the mobile Internet the mobility is also moving into new areas, e.g., imaging, games, video, multimedia, and across different types of networks. In this paper we explore why, what, and how of the network convergence, and identify how the industry viewpoints align and differ. We also identify the key barriers to achieving true network convergence. We then discuss the role of the Internet Protocol (IP) as the common thread that enables network convergence, and the key industry and standards initiatives to actually provide solutions and the equipment to implement a cost-efficient and high performance converged network. Sudhir Dixit joined Nokia Research Center in 1996, where he is currently a Research Fellow and works on next generation wireless networks. From 1996 to 2003 he was a Senior Research Manager, focusing on IP/ATM, wireless, content networks, and optical networks. Prior to that he worked at NYNEX Science & Technology (now Verizon), GTE (now Verizon), Codex Motorola, Wang, Harris, and STL (now Nortel Europe Labs). He has published or presented over 150 papers, published three books, and holds 14 patents. He is on the Editorial Board of the IEEE Communications Magazine, Springer's Wireless Personal Communications Journal, and KIC's Journal of Communications and Networks. He received a B.E. degree from MANIT, Bhopal, India, an M.E. degree from BITS, Pilani, India, a Ph.D. degree from the University of Strathclyde, Glasgow, Scotland, and an M.B.A. degree from Florida Institute of Technology, Melbourne. He is a Fellow of IEE (UK) and IETE (India). He represents Nokia on the Steering Board of the Wireless World Research Forum, and is also Chair of the SIG on Self-Organization of Wireless World Systems.     

微电子封装的新进展领域及对SMT的新挑战

介绍了几种微电子新型封装材料,如LTCC、AIN、金刚石、AI-Sic和无铅焊接材料等,论述了正在发展中的新型先进封装技术,如WLP、3D和SIP等,并对封装新领域MEMS和MOEMS作了简介.最后,就这些新技术对SMT的新挑战作了些探讨.     

卫星通信组呼业务MAC层研究

组呼通信在指挥调度中有着重要作用,而在一些地面没有基站的地方,就无法正常使用。卫星通信具有无视地形,通信范围广,不易受陆地灾害影响,易于建设等优点。把卫星通信和组呼通信结合在一起的卫星组呼通信技术兼顾两者的优点,能更好的发挥指挥调度这一作用。当前卫星组呼通信采用固定频率方式,组呼成员在一个频率下进行通信,这种方式实用性不好。本文研究的是移动卫星组呼,在GMR-1系统的基础上研究了卫星组呼通信中MAC层的功能,提出了MAC-Ready-Gcc、MAC-Dedicated-Gcc这两个为了支持组呼的状态,并针对在MAC层发生的PTT竞争提出了一种回退策略。     

一个具有附益性及保序性算子的形态学非局部拓展

近年，形态学非局部拓展工作在图像处理领域受到众多关注.而附益性算子是经典形态学的最基本形式，也是形态学分析方法最重要的变换工具.为此，一些研究者就形态学非局部拓展中如何保持算子的附益性开展工作.本文从理论及实例两个方面说明，相关拓展工作为保持算子的附益性而丢失了保序性的不足；进一步，通过设计非局部权值的获取过程，并结合现有工作，本文提出了一个新的形态学非局部拓展，并定理证明了所得算子同时具备附益性及保序性两个重要性质；人工合成图像及自然图像上的仿真实验也表明了本文所提算法的有效性.     

X-ray metrology for high-k atomic layer deposited HfxZr1−xO2 films

Hafnium-based dielectrics are the most promising material for SiO₂ replacement in future nodes of CMOS technology. While devices that utilize HfO₂ gate dielectrics suffer from lower carrier mobility and degraded reliability, our group has recently reported improved device characteristics with a modified Hf_xZr_1−xO₂ [R.I. Hegde, D.H. Triyoso, P.J. Tobin, S. Kalpat, M.E. Ramon, H.-H. Tseng, J.K. Schaeffer, E. Luckowski, W.J. Taylor, C.C. Capasso, D.C. Gilmer, M. Moosa, A. Haggag, M. Raymond, D. Roan, J. Nguyen, L.B. La, E. Hebert, R. Cotton, X.-D. Wang, S. Zollner, R. Gregory, D. Werho, R.S. Rai, L. Fonseca, M. Stoker, C. Tracy, B.W. Chan, Y.H. Chiu, B.E. White, Jr., in: Technical Digest - International Electron Devices Meet, vol. 39, 2005, D.H. Triyoso, R.I. Hegde, J.K. Schaeffer, D. Roan, P.J. Tobin, S.B. Samavedam, B.E. White, Jr., R. Gregory, X.-D. Wang, Appl. Phys. Lett. 88 (2006) 222901]. These results have lead to evaluation of X-ray reflectivity (XRR) for monitoring high-k film thickness and control of Zr addition to HfO₂ using measured film density. In addition, a combination of XRR and spectroscopic ellipsometry (SE) is shown to be a fast and non-intrusive method to monitor thickness of interfacial layer between high-k and the Si substrate.     

A Fault-Tolerant Scheme for Mobility Management in PCS Networks

One of the most important and challenging issues in the design of personal communication service (PCS) systems is the management of location information. In this paper, we propose a new fault-tolerant location management scheme, which is based on the cellular quorum system. Due to quorum's salient set property, our scheme can tolerate the failures of one or more location server(s) without adding or changing the hardware of the systems in the two-tier networks. Meanwhile, with a region-based approach, our scheme stores/retrieves the MH location information in the location servers of a quorum set of the local region as much as possible to avoid long delays caused by the possible long-distance of VLR and HLR. Thus, it yields better connection establishment and update delay. Ming-Jeng Yang received the M.S. degree in computer science from the Syracuse University, New York, in 1991, and the Ph.D. degree in computer science from National Taiwan Normal University, Taiwan, in 2004. He is an associate professor in the Department of Information Technology, Takming College, Taiwan. His research interests include wireless networks, mobile computing, fault-tolerant computing, and distributed computing. He is a member of the IEEE Computer Society and the ACM. Yao-Ming Yeh received the B.S. degree in computer engineering from National Chiao-Tung University, Taiwan, in 1981, and the M.S. degree in computer science and information engineering from National Taiwan University, Taiwan, in 1983. In August 1991, he received the Ph.D. degree in the Department of Electrical and Computer Engineering, The Pennsylvania State University, Pa., U.S.A. He is a professor in the Department of Information and Computer Education, National Taiwan Normal University, Taiwan. His research interests include fault-tolerant computing, web and XML computing, and distributed computing.     

LTE和LTE-Advanced关键技术综述

为满足移动宽带业务的需要,LTE正日渐成熟,它采用扁平化网络架构,关键技术包括OFDM、更高阶调制、HARQ、先进的多天线技术、快速同步技术、灵活的控制信道设计、自适应资源分配、干扰抑制技术等。有关LTE-Advanced的讨论也以展开,考虑的技术包括聚合多载波、高阶MIMO、智能中继、异构网络、协调多点发送和先进的干扰管理。