天线罩交叉瞄准误差成因分析

提出了均匀对称天线罩具有交叉瞄准误差的可能性,通过对天线罩入射波垂直分量的精确推导,进而对均匀对称天线罩交叉瞄准误差的产生机理进行了严格分析,指出了均匀对称天线罩产生交叉瞄准误差的条件,即完全均匀对称的天线罩在非垂直、水平极化情况下将产生交叉瞄准误差。并通过理论计算天线罩的瞄准误差进行了验证。而对天线罩的交叉瞄准误差实测结果也与上述结论吻合。     

提高数控加工精度的工艺措施

本文简要介绍了数控机床在加工零件时容易产生的几种误差现象，分析了误差产生的原因，即超程、欠程和传动误差等，并针对这些影响加工精度的因素提出了解决方案。     

高分辨SAR运动误差分析

分析了高分辨合成孔径雷达（SAR）成像中存在的运动误差,并从理论上分析了位置误差和角度误差对脉冲压缩的影响,理论分析表明运动误差对方位向相位造成的影响是主要的。在位置误差分析的基础上讨论了近似运动补偿产生的残余相位误差。然后在理论分析的基础上,对近似补偿产生的残余误差进行了仿真,验证了运动补偿的难点在于如何提高运动参数的精度以补偿方位向的相位误差。     

热电偶冷端温度误差补偿探讨

热电偶是常用的测温传感器,但测量时容易产生冷端误差.分析了热电偶测温产生冷端误差的原因,提出了采用补偿电桥法、延引热电极法和修正法等进行冷端温度误差补偿,从而提高了测量精度.     

基于MATLAB的连续信号数字谱分析

通过MATLAB语言，对连续函数进行了数字谱分析，详细介绍了连续时间信号进行数字谱分析的基本思路，并解释产生的混叠误差、栅栏效应、截断误差等，同时对产生误差的原因以及减少误差的相应措施进行了分析。     

MLS方位与仰角天线对准误差引起系统误差的分析

本文对微波着陆系统(MLS)地面方位和仰角天线安装时的对准误差进行了论述，并对其引起的系统误差进行了分析及数学推导，给出了对准误差中，方位天线的侧倾和偏离是产生系统横向误差的主要因素，仰角天线的侧倾和俯仰是产生系统垂直误差的主要因素。     

机载雷达组网导航定位误差仿真分析

机载雷达组网具有雷达组网和空中机动的综合优势.获取组网中载机导航定位的准确数据是目标定位的一个重要问题.文中对机载雷达组网时导航定位误差影响目标定位的误差机理进行了理论推导,重点对导航定位误差产生的目标定位误差进行了仿真分析,得出了两者之间的对应关系及导航定位误差产生的目标定位不一致性这一不可忽略的重要结论.     

一种基于OTA的降压型LED恒流电路

设计了一种LED恒流驱动电路,芯片内部电路由误差放大模块和PWM波形产生模块组成,外部电路为一个BUCK型恒流电路。误差放大模块中采用了一个跨导放大器,将采样电压与基准电压做比较,产生误差电流,反馈电容作为跨导放大器的负载,产生了误差电压信号。误差信号与锯齿波相比较产生PWM信号,控制外部BUCK电路的开关管对LED电流进行平衡。采用CSMC0.5μm的标准CMOS工艺库进行电路仿真,结果表明本电路电流平衡的稳定度较高,满足中小功率的LED串并联的驱动。     

频率扫描干涉中参考干涉仪的非线性误差分析

针对频率扫描激光干涉测距系统的参考干涉仪中存在的大量光学元件会产生非线性误差,本文基于偏振分光镜(PBS)的非理想分光性能分析了非线性误差的产生机制,推导出PBS非理想分光性能条件下的非线性误差模型,并提出了消除非线性误差的改进方法。利用MATLAB进行建模仿真表明,PBS非理想透射率和反射率对非线性误差的影响为二次谐波,透射率和反射率相差越大,非线性误差越大,当二者值相等时非线性误差大幅减小。当PBS反射率为0.90且透射率为0.97时,用传统的正交检测方法产生最大为383.3 kHz的非线性误差,而采用本文提出的方法只存在5.3 kHz的线性误差。     

对影响1/4波片使用精度因素的理论研究

为了探究1/4波片在使用过程中产生误差的原因,以石英1/4波片的实验结果为基础,分别从材料的双折射特性、实验调节误差以及温度变化的影响等三个方面,对波片产生误差的原因进行了理论分析,提出了提高1/4波片使用精度的方法.从分析结果可以看出;温度变化的影响是产生误差的最主要的因素,但双折射特性和实验操作误差的影响也不可忽略.     

Students’ thoughts about the importance and costs of their mobile devices’ features and services

In recent years, handheld devices have become one of the fastest growing communication gadgets. Mobile technology is becoming widespread and research in this area is urgently needed. Using a survey instrument, the thoughts of male and female students regarding the importance and costs of mobile devices were investigated. It was found that students tend to consider the following features important: battery life, mp3 player, video camera, photo camera, storage memory, Bluetooth, design and elegance, clock, calendar, organizer and reminder. Also, they are eager to spend an amount of money so as their mobile device to support them. On average, both genders would pay extra money for such features. However, the majority of females think less of the price than males do. On the contrary, most of the respondents do not consider the following important: touch screen, voice commands, chat, teleconference, encryption and cryptography, common use of files, printing. Therefore, they would not spend any money for these features. Interested decision makers would try to increase their interest on such features. Moreover, all respondents appear to own a mobile phone while most of them do not have Internet connection at home. In general, some gender differences are found in the importance and costs of the mobile devices, but they are not statistically significant.     

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.     

胆小管超微细胞酶学研究

以电镜细胞化学的方法,观察了小鼠胆小管酶的分布。观察的12种酶中,NDPase和G6Pase三种酶分布于胆小管微绒毛;AlPase、Na~+-K~+ATPase、Mg~(++)-ATPase、Ca~(++)-ATPase、CMPase、ACase和5＇-Nase等7种酶分布于胆小管微绒毛,也分布于肝细胞邻接面细胞膜和Disse间隙微绒毛;ACPase、细胞色素氧化酶以及线粒体ATPase不分布胆小管微绒毛,也不分布Disse间隙微绒毛和肝细胞膜。据信,胆小管微绒毛上的酶参与胆汁成份的转运,提供转运所需能量以及还可能与某些代谢过程有关。本实验中磷酸水解酶类使用的铈基法及亚铁氰化钾半还原的锇酸后固定法,效果优于铅法。     

HiBRID-SoC: A Multi-Core SoC Architecture for Multimedia Signal Processing

The HiBRID-SoC multi-core system-on-chip architecture targets a wide range of multimedia applications with particularly high processing demands, including general signal processing applications, video de-/encoding, image processing, or a combination of these tasks. For this purpose, the HiBRID-SoC integrates three fully programmable processors cores and various interfaces onto a single chip, all tied to a 64-Bit AMBA AHB bus. The processor cores are individually optimized to the particular computational characteristics of different application fields, complementing each other to deliver high performance levels with high flexibility at reduced system cost. The HiBRID-SoC is fabricated in a 0.18 μm 6LM standard-cell CMOS technology, occupies about 81 mm², and operates at 145 MHz. An MPEG-4 Advanced Simple Profile decoder in full D1 resolution requires about 120 MHz for real-time operation on the HiBRID-SoC, utilizing only two of the three cores. Together with the third core, a custom region-of-interest (ROI) based surveillance application can be built.Hans-Joachim Stolberg received the Dipl.-Ing. degree in electrical engineering from the University of Hannover, Germany, in 1995.From 1995 to 1996, he was with the NEC Information Technology Research Laboratories, Kawasaki, Japan, working on efficient implementations of video compression algorithms. Since 1996, he has been with the Institute of Microelectronic Systems at the University of Hannover as a Research Assistant. During summer 2001, he was a Monbukagakusho Research Fellow at the Tokyo Institute of Technology, Japan. His current research interests include VLSI architectures for video signal processing, performance estimation of multimedia schemes, and profile-guided memory organization for signal processing and multimedia applications.Mladen Bereković received the Dipl.-Ing. degree in electrical engineering from the University of Hannover, Germany, in 1995.Since then he has been a Research Assistant with the Institute of Microelectronic Systems of the University of Hannover. His current research interests include VLSI architectures for video signal processing, MPEG-4, System-on-Chip (SOC) designs, and simultaneously multi-threaded (SMT) processor architectures.Sören Moch received the Dipl.-Ing. degree in electrical engineering from the University of Hannover, Germany, in 1997.Since then he has been Research Assistant with the Laboratory for Information Technology, University of Hannover. His current research interests are in the area of processor architectures for image, video and multimedia signal processing applications.Lars Friebe studied electrical engineering at the Universities Ulm and Hannover, Germany. In 1999, he worked at the NEC System ULSI Research Laboratory in Kanagawa, Japan. He received the Dipl.-Ing. degree in electrical engineering from the University of Hannover, Germany, in 1999.Since then he has been a Research Assistant with the Laboratory for Information Technology, University of Hannover. His current research interests are in the area of parallel programmable VLSI architectures for real-time image processing.Mark B. Kulaczewski started his studies in electrical engineering at the University of Hannover, Germany. In 1994, he transferred to Purdue University, West Lafayette, USA, and received the M.S. degree in electrical engineering in 1996.Since 1997 he has been a Research Assistant at the Laboratory for Information Technology and the Institute of Microelectronic Systems, University of Hannover. His current research interests include programmable real-time architectures for video coding and image segmentation, and instruction-set extensions for cryptographic applications.Sebastian Flügel was born in Crivitz, Germany, in 1975. He received his Dipl.-Ing. degree from the Department of Electrical Engineering of the University of Rostock in 2001.Since then he has been a Ph.D. candidate at the Institute of Microelectronic Systems at the University of Hannover. He works in the field of architectures and systems for video processing systems. His focus is on algorithms for video encoding and the development of optimized hardware architectures.Heiko Klußmann received the Dipl.-Ing. degree in computer engineering from the University of Hannover, Germany, in 2002.Since then he has been a Research Assistant with the Institute of Microelectronic Systems of the University of Hannover. His current research interests are in the area of programmable architectures for real-time video signal processing.Andreas Dehnhardt was born in Frankfurt am Main, Germany, in 1976. He received his Dipl.-Ing. degree in electrical engineering from the University of Hannover, Germany, in 2002.Since then, he has been a Research Assistant with the Institute of Microelectronic Systems, University of Hannover. His current research interests include programmable architectures for multimedia applications and implementation of real-time MPEG-4 encoding schemes.Peter Pirsch received the Ing. grad. degree from the engineering college in Hannover, Hannover, Germany, in 1966, and the Dipl.-Ing. and Dr.-Ing. degrees from the University of Hannover, in 1973 and 1979, respectively, all in electrical engineering.From 1966 to 1973 he was employed by Telefunken, Hannover, working in the Television Department. He became a Research Assistant at the Department of Electrical Engineering, University of Hannover, in 1973, a Senior Engineer in 1978. During 1979 to 1980 and in Summer 1981 he was on leave, working in the Visual Communications Research Department, Bell Laboratories, Holmdel, NJ. During 1983 to 1986 he was Department Head for Digital Signal Processing at the SEL research center, Stuttgart. Since 1987 he is Professor in the Department of Electrical Engineering, since 2002 in the Department of Computer Science at the University of Hannover. He served as Vice President Research of the University of Hannover from 1998 to 2002. His present research includes architectures and VLSI implementations for image processing applications, rapid prototyping and design automation for DSP applications. He is the author or coauthor of more than 200 technical papers. He has edited a book on VLSI Implementations for Image Communications (Elsevier 1993) and is author of the book Architectures for Digital Signal Processing (John Wiley 1998).Pirsch is a member of the IEEE, the German Institute of Information Technology Engineers (ITG) and the German Association of Engineers (VDI). He was recipient of several awards: the NTG paper price award (1982), IEEE Fellow (1997), IEEE Circuits and Systems Golden Jubilee Medal (1999). He was member or chair of several technical program committees of international conferences and organizer of special sessions and preconference courses. He has held several administrative and technical positions with the IEEE Circuits and Systems Society and other professional organizations. Dr. Pirsch currently serves as Vice President Publications of the IEEE Circuits and Systems Society. Since 2000 he is chairman of the Accreditation Commission for Engineering and Informatics of the Accreditation Agency for Study Programs in Engineering, Informatics, Natural Science and Mathematics (ASIIN). Dr. Pirsch is chair of the VDI committee on Engineering Education.     

Metadata Design for Reconfigurable Protocol Stacks in Systems Beyond 3G

Global consensus on the next generation of wireless mobile communications, broadly termed “beyond 3G”, sketches a heterogeneous infrastructure comprising different wireless systems in a complementary manner and vested with reconfiguration capabilities, which support a flexible and dynamic adaptation of the wireless network and its spectrum resources to meet the ever-changing service requirements. For ubiquitous reconfiguration to become a practical capability of mobile communication systems, it is necessary to establish a global architecture for modeling, expressing, and circulating essential metadata related to reconfiguration, including reconfigurable device capabilities and semantic properties of protocol stacks. We outline the relevant standardization initiatives in the mobile domain, summarize existing work in reconfiguration-supporting architectures, and identify key shortcomings that may hinder the advent of ubiquitously reconfigurable systems. Further on, we point out some major limitations of current metadata standards in the mobile domain for the representation of capability information pertaining to reconfigurable protocol stacks. Next, we identify essential metadata classes in support of reconfigurable communication systems, introducing an associated object-oriented UML model. We elaborate on the design rationale of the UML model, presenting and discussing the alternative metadata representation standards and suitable encoding formats. Finally, we demonstrate the suitability of our UML model by applying our reconfiguration-supporting vocabulary in the cases of a standardized protocol stack of 3G mobile devices and stationary 3G cellular network elements. Vangelis Gazis received his B.Sc. and M.Sc. (Communication Networking) degrees from the Department of Informatics & Telecommunications of the University of Athens, Greece, in 1995, and 1998, respectively. He also received an M.B.A. degree from the Athens University of Economics and Business in 2001. Since 1996 until, he has been with the research staff of the Communication Networks Laboratory (CNL) of the University of Athens. He has participated in national and European research projects (MOBIVAS, ANWIRE) of the IST framework programme. He specializes in reconfigurable mobile systems and networks for beyond 3G, metadata and ontology languages, reflective and component middleware, adaptable services and open API frameworks for telecommunications. He is currently a Ph.D. candidate in the Department of Informatics & Telecommunications of the University of Athens. Nancy Alonistioti holds a B.Sc. degree and a Ph.D. degree in informatics and telecommunications from the University of Athens. Presently, she is a senior researcher in the Department of Informatics and Telecommunications of the University of Athens. In the past, she has held a research position with the Institute of Informatics and Telecommunications of NCSR “Demokritos” in the areas of protocol and service design and testing, mobile systems (UMTS), open architectures, and software defined radio systems and networks. Her current research interests are in reconfigurable mobile systems and networks beyond 3G, and adaptable services, pervasive computing and context awareness. She has participated in several national and European R&D projects, and has been the technical manager of the IST-MOBIVAS and IST-ANWIRE projects, which have had a focus on reconfigurable mobile systems, networks an respective service provision. She is currently a member of the management team and workpackage leader in the FP6 IST-E2R project on reconfigurability; she also serves as technical manager for the University of Athens in the FP6 IST-LIAISON project, which focuses on location based services in working environments. Dr Alonistioti is co-editor and co-author of the book entitled “Software defined radio, Architectures, Systems and Functions”, published by John Wiley in May 2003. She has authored over 55 publications in the area of mobile communications and reconfigurable systems and networks. Lazaros Merakos received the Diploma in electrical and mechanical engineering from the National Technical University of Athens, 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 the Electrical Engineering and Computer Science Department, University of Connecticut, Storrs. From 1986 to 1994, he was on the faculty of the Electrical and Computer Engineering Department, Northeastern University, Boston, MA. During the period 1993D1994, he served as Director of the Communications and Digital Processing Research Center, 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. 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 and Services (ACTS) and Information Society Technologies (IST) programs funded by the European Union (projects RAINBOW, Magic WAND, WINE, MOBIVAS, POLOS, ANWIRE, E2R, LIAISON). His research interests are in the design and performance analysis of communication networks, and wireless/mobile communication systems and services. He has authored more than 190 papers in the above areas. Dr. Merakos 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.     

SOI Technologies Overview for Low-Power Low-Voltage Radio-Frequency Applications

Thanks to their structure, the SOI technologies present several intrinsic advantages for analog and RF applications. Indeed, as it is well established now, these technologies allow the reduction of the power consumption at a given operating frequency. Moreover, the high-insulating properties of SOI substrates, in particular when high resistivity substrate is used, make that these technologies are perfect candidates for mixed-signal applications. In the present paper, we will discuss the performances of the SOI technologies in radio-frequency range. First of all, the high-frequency behavior of SOI substrates, thanks to the characterization of transmission lines, will be shown. The impact of the SOI substrate resistivity on the performances of passive components will also be analyzed. Then, an overview of RF performances of SOI MOSFETs for two different architectures, fully- and partially-depleted, will be achieved and compared to the bulk ones. Finally, the influence of some specific parasitic effects, such as the kink effect, the self-heating effect and the kink-related excess noise, on the RF performances of SOI devices will be studied, thanks to a specific high-frequency characterization.     

Energy-efficient resource allocation model for device-to-device communication in 5G wireless personal area networks

In general, there are several many devices that can overload the network and reduce performance. Devices can minimize interference and optimize bandwidth usage by using directional antennas and by avoiding overlapping communication ranges. In addition, devices need to carefully manage their use of resources, such as bandwidth and energy. Bandwidth is limited in wireless personal area networks (WPANs), so devices need to carefully select which data to send and receive. In this paper, an intelligent performance analysis of energy-efficient resource optimization model has been proposed for device-to-device (D2D) communication in fifth-generation (5G) WPAN. The proposed energy-efficient resource allocation in D2D communication is important because it helps reduce energy consumption and extend the lifespan of devices that are communicating with each other. By allocating resources in an efficient manner, communication between two devices can be optimized for maximum efficiency. This helps reduce the amount of energy needed to power the communication, as well as the amount of energy needed to power the device that is communicating with another device. Additionally, efficient resource allocation helps reduce the overall cost of communication, as the use of fewer resources results in a lower overall cost. The proposed efficient resource allocation helps reduce the environmental impact of communication, as less energy is used for communication. The proposed energy-efficient resource allocation model (EERAM) has reached 92.97% of energy allocation, 88.72% of power allocation, 87.79% of bandwidth allocation, 87.93% of spectrum allocation, 88.43% of channel allocation, 25.47% of end-to-end delay, 94.33% of network data speed, and 90.99% of network throughput.     

Essential Considerations in Implementing the Smart Antenna System for Downlink Beamforming

This paper addresses some essential problems that have to be taken into consideration in implementing the smart antenna base station (SABS) for downlink beamforming. In order to provide proper downlink beamforming as well as uplink beamforming, a pragmatic procedure of automatic calibration is proposed. Through the experimental test, we confirm that the proposed calibration technique has eliminated the problem of the phase differences of the signal path associated with each antenna. Also, in this paper, we first analyze the multipath condition under which the auxiliary pilot becomes indispensable for detecting the data transmitted on the data channel and what happens if the auxiliary pilot is not available. Then, the performance of the downlink beamforming utilizing the auxiliary pilot is analyzed through the computer simulations. Finally, we present a comparison of downlink communications to uplink ones in terms of throughputs available at each of uplink and downlink communications. Weon-Cheol Lee received the B.S, M.S, and Ph.D. degree in Electronic Communication Engineering from Hanyang University, Korea, in 1992, 1994, 2005, respectively. From 1994 to 2000, he was with LG Electronic Inc., where he had worked for developing the digital VCR, digital cable modem, digital TV. Since 2001, he has been a professor with department of information and communications, Yong-in Songdam College, Korea. His research interests include smart antennas, mobile communications beyond the third generation, digital broadcasting technology, and communication signal processing. Dr. Lee also received the Best Research Paper Award and Excellent Research Engineer Award from LG Electronics, respectively. Seungwon Choireceived the BS degree from Hanyang University, Seoul, Korea, and the M.S. degree from Seoul National University, Korea, 1980 and 1982, respectively, both in electronics engineering, the MS degree (computer engineering) in 1985, and the PhD degree (electrical engineering), in 1988, both from Syracuse University, Syracuse, NY. From 1988 to 1989 he was with the Department of Electrical and Computer Engineering of Syracuse University, Syracuse, NY, as an Assistant Professor. In 1989 he joined the Electronics and Telecommunications Research Institute, Daejeon, Korea. From 1990 to 1992 he was with the Communications Research Laboratory, Tokyo, Japan, as a Science and Technology Agency fellow, developing the adaptive antenna array systems and adaptive equalizing filters. He joined Hanyang University, Seoul, Korea, in 1992 as an assistant professor. He is a professor in the School of Electrical and Computer Engineering of Hanyang University. Since 2003, Dr. Choi has been serving as a Vice Chairman and the representative of the ITU region 3 for SDR (Software Defined Radio) Forum and as a Director of the HY-SDR Research Center, MIC, Korea. His research interests include digital communications and adaptive signal processing with a recent focus on the implementation of the smart antenna systems for both mobile communication systems and wireless data systems. Jae-Moung Kim received the BS degree from Hanyang University, Korea in 1974, the MSEE degree from University of Southern California, USA in 1981, and the PhD degree from Yonsei University, Korea in 1987. He was a Vice President of Radio {&} Broadcasting Technology Laboratory and Director of Satellite Communication System Department at Electronics and Telecommunications Research Institute (ETRI) from September 1982 to March 2003. Since April of 2003, he has been a Professor in the Graduate School of Information Technology and Telecommunications, Inha University. He is a board member of directors of Korean Institute of Communication Science (KICS), a Vice President of Korea Society of Broadcast Engineers (KOSBE) and a senior member of IEEE. His research background is telecommunication systems modeling and performance analysis of broadband wireless access systems, mobile communications, satellite communications and broadcasting transmission technologies.     

Towards Mobile Ubiquitous Service Environment

In this article we present a perspective on future vision of mobile communications and services which is referred to as Mobile Ubiquitous Service Environment (MUSE). Based on analysis of wireless communications and services, we exploit a conceptual model for MUSE via a top-down approach. The conceptual model consists of three major elements: Terminal Service Environment (TSE), Network Service Environment (NSE) and User Identity (UID). The concept of Always the Best Experience (ABE) is addressed as the hinge in design and development such that the user-centric services could be provided automatically and intelligently in the future diverse wireless world Based on these, we further discuss the issues on design and implementation of architecture of future wireless communication system. Requirements for architecture brought by the new features of MUSE are listed. Moreover, we also address several tradeoffs that should be taken into consideration in design. Finally, the deployment challenges for MUSE, such as reflectiveness of system, security and privacy, as well as peer-to-peer AAA are predicted.Ji Yang received PhD degree on Circuit and System, Bachelor degree on Telecommunication Engineering from Beijing University of Posts and Telecommunications (BUPT) in 2002 and 1993 respectively. Currently, he is an associate professor of BUPT, chief technical supervisor of Wireless Technology Innovation Institute, and vice manager of MTlab of Sino-Germany Software Institute. He leads the research on service and application in Future Forum in China. He also made much contribution to the China Communication Standardization Association (CCSA), including the vision of future Mobile Ubiquitous Service Environment, architecture of future B3G mobile terminal, etc. His research interests include architecture design for mobile ubiquitous networks, theory of self-organization, etc.Zhang Ping is now the professor of Beijing University of Posts and Telecommunications and director of Wireless Technology Innovation (WTI) Institute, BUPT. He has also served on the senior member of C3G Group, China MOST 863 future mobile communication FuTURE project, vice-chairman of China FuTURE Forum, and member of Vision Committee of World Wireless Research Forum(WWRF), he was vice chair of WWRF in 2005. He is also invited as the consultants for many domestic and oversea communication companies. He is very active on the international research activity on Beyond 3G area. He also participated in several European projects such as E2R and MOCCA. Until now, he has published 6 books, around 400 publications in journals and conferences in the area of telecommunications. His main research interests are theory and applications in wireless communication area. He was awarded by government, city of Beijing and Ministry of Information Industry several times for his great contribution to the industry and research activity in China.Hu Zheng is a PH.D candidate in mobile communications engineering in Wireless Technology Innovation Institute (WTI) at Beijing University of Posts and Telecommunications (BUPT). He received B.S degree from Nanjing University of Posts and Telecommunications in 2002, majoring in computer communications engineering. He currently works on serivce aspects of mobile ubiquitous communication system with focus on design and performance evaluation of interaction protocols and services in self-organized service environment.Wang Xu received the B.Tech. degree in electronic engineering from Beijing Polytechnic University (now named as Beijing University of Technology), Beijing, China, in 2002. Now he is working for his Ph.D. degree in Wireless Technology Innovation (WTI) Institute, Beijing University of Posts and Telecommunications (BUPT). His current interests include wireless communications in personal area, ad hoc networks and peer-to-peer system.Li Yinong received the BS degree major in Telecommunication Engineering in 1993 from Beijing University of Posts and Telecommunications, the MS degree and PhD degree major in Telecommunication and Electronic System in 1995 and 2003 from the Beijing University of Posts and Telecommunications. He is currently a lecture of STE (School of Telecommunication Engineering) of BUPT. His main research interests include service modeling, service composition approach, and intelligent service. In BUPT, he has given several lectures to both graduate and undergraduate students such as Information Theory, Speech Recognition, Pattern Recognition and Artificial Intelligence.     

无人机SAR/MTI侦察技术中若干问题的探讨

本文介绍了国外无人机SAR／MTI雷达研究现状和发展方向,列举了X、Ka,Ku三种频段SAR／MTI雷达主要技术指标,重点从工程实现的角度对SAR／MTI雷达技术中若干问题进行了探讨,包括无人机、SAR的成像模式和MTI兼容技术、频段选择、SAR成像实时数据的传输方式、惯导系统、最后讨论了成像算法。