浅析网格技术在现代远程课程中的应用

现代远程教学是对正规教育的有益补充，将网格技术运用到远程教学中，将推动教育信息化的发展。本文介绍了网格技术的概念和特征，分析了网格技术在现代远程教学中的应用，并概述了基于网格技术的远程教学系统模型的构成。     

远程教学中动画技术的应用研究

远程教学作为未来教育的一种发展趋势,受到了国内外教育工作者的关注.而教学课件呈现质量的好坏与动画技术息息相关.本文介绍了远程教学的发展现状及意义,探讨了远程教学中的动画技术,并分析了Flash动画技术在远程教学应用中的特点.     

创建现代远程教学系统的探索与实践

基于卫星通信技术、互联网技术和流媒体技术创建的新型远程教学系统,为构建终身学习提供了有力支持。人们在创建远程教学系统时,都希望实现为学习者提供在任何时间、任何地点自主学习的环境,能最大限度地满足各类人员的学习需求,并保证良好的学习效果。远程教学中信息传送系统能否为传送教学信息提供强有力的、可靠的支持,这是决定远程教学效果的关键环节之一。本文对构建现代远程教学系统进行了探讨,并结合自行研发的清华大学远程教学播出系统,阐述了播出系统的构成及技术特点。     

电子学太赫兹技术研究概述

太赫兹技术是交叉前沿技术,本文首先介绍了太赫兹及电子学太赫兹技术基本概念,然后介绍了国内外电子学太赫兹器件的现状和应用情况,重点介绍了电子学太赫兹技术在通信及雷达方面的应用现状。最后给出了电子学太赫兹应用研究的具体内容及发展方向。     

个性化远程教学系统中决策树方法的应用研究

现代远程教学是随着计算机网络技术和多媒体技术的发展而产生的一种新型的教学形式。因材施教,个性化教学一直是远程教学服务系统追求的目标,如何从大量堆积的学习者信息中发现有价值的规律,实现远程教学系统的个性化教学,已经成为教育研究者一个亟待解决的课题。探讨了如何将数据挖掘技术中的决策树方法应用于远程教学系统中来为学习者进行分类,以实现针对不同学生的个性化教学。     

基于流媒体技术的远程教学系统设计

远程教学系统是基于Internet网和现代计算机技术、与教学理论相结合、为教学系统的远程教学过程提供服务的软件系统.系统运用面向对象的设计思想,采用UML语言抽象对象,完成了一个远程教学系统的设计.     

分布式远程教学平台在中外合作教学中的应用探究

教育国际化是当今世界教育发展的潮流,中外合作教学已成为教育国际化的一种模式。分布式远程教学平台软件是合作模式实现的技术基础。本文研究了远程教学信息发布与管理,给出了一个完整的基于教学的远程教学平台的结构和系统整体设计思想,为资源的有效共享提供技术解决方案。     

视频会议技术和虚拟现实技术在远程教学系统中的应用

远程教学是在开放式教育网络基础上构建的学习系统。本文对现阶段远程视频会议技术及其在远程教学系统中的应用进行分析,并对虚拟现实技术进行讨论,从而得出远程教学的新模式。视频会议技术可将音视频数据在多个终端设备间进行实时传输,达到即时通信的效果;虚拟现实技术可构建物体及其运动的三维信息,同时嵌入文本、图像等二维信息,使用户置身于三维环境中,给人以真实感受。本文认为将视频会议技术与虚拟现实技术结合,将产生新模式,能满足师生对远程教学的高需求,提高教学质量,实现更理想的远程教学系统。     

异构网络的多终端教学方案设计与实现

基于三网融合实验室网络环境,应用H.264编码与P2P技术,设计了异构网络的视频监控与远程教学方案,实现了智能手机、计算机、平板、电视屏实时监控或者远程教学.重点介绍了网络摄像机在实验室网络上的组建方案与网络技术在此方案中的应用.方案中体现了现代网络技术在视频监控、远程教学和高校信息化建设中取得的显著效果.     

改版前言

《电子器件》(电子学及其应用)铅印新版和大家见面了,它是由我们电子工程系、无线电电子学研究所和南工微电子中心联合主办的、电子学科方面的学术性刊物,每年出版四期(季刊)。主要内容涉及到我系(所)几乎所有的学科范畴,也就是:真空电子学,半导体电子学以及固体电子学。具体来说,它包括微波电子学、电子(离子)束和显示技术;激光与红外、半导体物理与器件、集成电路与微电子技术、太阳能、光纤技术与集成光学、真空物理与技术、表面科学与分析技术、传感技术、电子材料和薄膜,以及电光源和照明技术等诸方面。     

Designing an Embedded Video Processing Camera Using a 16-bit Microprocessor for a Surveillance System

This paper describes the design and implementation of a hybrid intelligent surveillance system that consists of an embedded system and a personal computer (PC)-based system. The embedded system performs some of the image processing tasks and sends the processed data to the PC. The PC tracks persons and recognizes two-person interactions by using a grayscale side view image sequence captured by a stationary camera. Based on our previous research, we explored the optimum division of tasks between the embedded system and the PC, simulated the embedded system using dataflow models in Ptolemy, and prototyped the embedded system in real-time hardware and software using a 16-bit CISC microprocessor. This embedded system processes one 320 × 240 frame in 89 ms, which yields one-third of the rate of 30 Hz video system. In addition, the real-time embedded system prototype uses 5.7 K bytes of program memory, 854 K bytes of internal data memory and 2 M bytes external DRAM. Koichi Sato is a Ph.D. student in the Department of Electrical and Computer Engineering at The University of Texas at Austin. He earned his B.S. in University of Tokyo, Japan in 1993. He worked for Automotive Development Center in Mitsubishi Electric Corporation where he was involved in lane and automobile recognition in vehicle video processing products such as automatic cruise control and drowsiness detection systems. He enrolled in the current University at 1998 and received an M.S in 2000. In his Master's thesis he worked on human tracking and human interaction recognition. His current work includes velocity extraction using the TSV transform, object tracking, and 3D object reconstruction. Brian L. Evans is a tenured Associate Professor in the Department of Electrical and Computer Engineering at The University of Texas at Austin. His research and teaching efforts are in embedded real-time signal and image processing systems. In signal processing, his research group is focused on the design and real-time software implementation of ADSL and VDSL transceivers, for high-speed Internet access. In image processing, his group is focused on the design and real-time software implementation of high-quality halftoning for desktop printers, smart image acquisition for digital still cameras, and 3-D sonar imaging systems. In signal and image processing, Dr. Evans has published over 100 refereed conference and journal papers. Dr. Evans is the primary architect of the Signals and Systems Pack for Mathematica, which has been on the market since October 1995. He was a key contributor to UC Berkeley's Ptolemy Classic electronic design automation environment for embedded systems, which has been successfully commercialized by Agilent and Cadence. His BSEECS (1987) degree is from the Rose-Hulman Institute of Technology, and his MSEE (1988) and PhDEE (1993) degrees are from the Georgia Institute of Technology. From 1993 to 1996, he was a post-doctoral researcher in the Ptolemy project at UC Berkeley. He is a member of the Design and Implementation of Signal Processing Systems Technical Committee of the IEEE Signal Processing Society, and a Senior Member of the IEEE. He is the recipient of a 1997 National Science Foundation CAREER Award. J.K. Aggarwal has served on the faculty of The University of Texas at Austin College of Engineering since 1964 and is currently Cullen Professor of Electrical and Computer Engineering and Director of the Computer and Vision Research Center. His research interests include computer vision and pattern recognition focusing on human motion. A Fellow of IEEE since 1976 and IAPR since 1998, he received the Senior Research Award of the American Society of Engineering Education in 1992, the 1996 Technical Achievement Award of the IEEE Computer Society and the graduate teaching award at The University of Texas at Austin in 1992. He has served as Chairman of the IEEE Computer Society Technical Committee on Pattern Analysis and Machine Intelligence (1987--1989); Director of the NATO Advanced Research Workshop on Multisensor Fusion for Computer Vision, Grenoble, France (1989); Chairman of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition (1993), and President of the International Association for Pattern Recognition (1992--1994). He is a Life Fellow of IEEE and Golden Core member of IEEE Computer Society. He has authored and edited a number of books, chapters, proceedings of conferences, and papers.     

All-Learning: The state of the art of the models and the methodologies educational with ICT

This paper presents a systematic review of models and methodologies that integrate information and communication technologies (ICT) and education. The systematic review was based on the methodology of Kitchenham. The steps used and developed correspond to the steps proposed in the methodology. The starting point of the review are the research questions, then keywords, selection of the databases, definition of the inclusion and exclusion criteria, the definition of the search chains, search process and selection of papers, the analyzes of the paper and the results of the systematic review to answer the questions posed. In the systematic review, 919 papers were found in 6 academic databases and 129 relevant papers were selected. The work developed intends to know the different models and methodologies that integrate the ICT and the education. Develop an analysis and characterize to find common elements among models and methodologies. The idea is to find limitations, disadvantages and spaces that allow to propose a new model. This systematic review is the first step in the development of a doctoral research in which the development of a U-Learning model based on Connective Learning and Experience Learning is proposed.     

Mechanical Sensitivity Enhancement of an Area-Changed Capacitive Accelerometer by Optimization of the Device Geometry

A study of the enhancement of the mechanical sensitivity of an area-changed capacitive accelerometer by optimization of the device geometry is presented. The movable mass of the accelerometer was designed with many fingers connected in parallel and suspended over the stationary electrodes composed of differential comb fingers by means of mechanical beams anchored onto the substrate. The maximum displacement possible based on the chosen design structure was determined. From this displacement value the spring constant was calculated, and based on this spring constant value various combinations of the beam length and width were selected. The lengths and the widths were then varied and simulated using the Coventorware 2001.3 software. This was done as theoretical analysis showed that the mechanical beam dimensions are significantly more dominant in the overall device sensitivity. The displacement and spring constant variations with the beam dimensions at an applied acceleration was observed and analyzed. The same process was done for the number of fingers, length and thickness of each finger. Each of these was done in isolation based on the optimum geometry of the mechanical beams and tested to ensure that alterations of these aspects do not have a significant effect on the overall sensitivity. The modal and harmonic analysis were also simulated and observed to ensure the linearity and the stability of the dominant mode of the operation of the device. Optimum results of the device geometry are presented and discussed, along with suggested next steps.Badariah Bais received the B.S. and M.S. degrees from the Worcester Polytechnic Institute, Worcester, MA, in 1990 and 1992, respectively. Since 1997, she has been serving at the Department of Electrical, Electronics and Systems Engineering at Universiti Kebangsaan Malaysia as a teaching staff. She is currently pursuing her Ph.D. in Microelectronics at the Institute of Microengineering and Nanoelectronics (IMEN) at Universiti Kebangsaan Malaysia. Her research interests include MEMS sensors and microfabrication. She is a member of the Institute of Electrical and Electronics Engineer (IEEE).Burhanuddin Yeop Majlis received his Ph.D. in Microelectronics from University of Durham, UK in 1988, MSc. in Microelectronics from University of Wales, UK in 1980 and BSc. (Hons.) in Physics from Universiti Kebangsaan Malaysia in 1979. Now he is the director of Institute of Microengineering and Nanoelectronics (IMEN). He is a senior member of the Institute of Electrical and Electronics Engineer (IEEE) and the Chairman of IEEE Electron Devices Malaysia Chapter since 1994. He is also a member of Malaysian Solid State Science and Technology (MSSS). He has published three text books in electronics and one book on Integrated Circuits Fabrication Technology for undergraduate courses and more than 110 academic research papers. His current interest are MEMS sensor for automotive and RF applications.     

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.     

米酵菌酸对小鼠肝和心肌细胞毒性作用的超微结构研究

目的：观察米酵菌酸对小鼠肝、心肌细胞毒性作用的超微结构改变，探讨米酵菌酸中毒的机理，方法：小鼠腹腔注射不同剂量的米酵菌酸，2h后取其肝和心肌组织，通过电镜观察其细胞超微结构的改变，结果：电镜下可见肝细胞和心肌细胞的线粒肿胀，内嵴断裂，模糊或消失，基质局部或全部空亮，呈囊泡样变，偶见其中含髓样小体，上述线粒体内嵴和膜结构的病变随米酵菌酸剂量的增加而加重，结论：米酵菌酸对小鼠肝、心肌细胞毒性作用以线粒体的损伤较为突出，因此我们认为，线粒体内膜的破坏造成线粒体的功能障碍，影响细胞呼吸，使细胞缺氧导致小鼠中毒死亡。     

百年电子学--纪念真空电子管发明一百周年

电子学的崛起、发展和广泛应用是20世纪最伟大的科学技术领域之一.在电磁波理论和自由电子发展的基础上,1904年出现了第一只真空二极电子管,一般认为这标志着电子学的诞生.电磁波频谱资源的开发和利用是电子学发展的基础和动力.从电磁频谱统一的观点看,光已经象微波一样进入到电子学的领域,成为无线电电子学中不可分割的组成部分.电子学的基本任务是:研究带电粒子流与电磁场相互作用的物理概念和物理过程,以及利用相互作用的不同物理机制实现粒子与场之间能量有效转化的方法和条件.从电子器件的观点看,电子学可分为真空电子学与固态电子学;而从电子运动规律的观点看,现代电子学将处理自由电子,准自由电子和束缚电子的运动规律及其与电磁场的相互作用.1958年,电子学领域出现三个重要发现和发明:集成电路、激光和相对论自由电子的回旋辐射.相应的,半导体电子学(微电子学)、激光电子学和相对论电子学等现代电子学领域则发端于此.电子器件小型化、微型化、功能集成化将电磁频谱的开拓和占领推向光波和红外毫米波.     

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。     

Advanced Interfacial Design for Electronic Skins with Customizable Functionalities and Wearability

Electronic skins (E-skins), which are intelligent extensions of the human skin, are in great demand because of the rapid development of information technology and intelligence in human civilization. Essentially, E-skin systems are composed of functional and interface components. The function portion carries out various functions like sensing, power production, and therapy. In addition to ensuring consistent wear and comfort, the interface of the E-skin system is necessary for the transfer of energy or mass between the skin and the functional components of the E-skin system. The interface serves as the foundation, conduit, and link between the skin and functional components of E-skin systems. The wearability and functionality of the E-skin system are significantly impacted by the interfacial adhesion and the intermediate effect. It is crucial to build the interface in accordance with the functions of the E-skin system. However, there are few reviews on the impact of the interface on the functionality and wearability of E-skins. Here, the design of the E-skin interface is thoroughly reviewed, taking into account how skin adhesion mechanisms affect wearability and function. At last, the future development direction and perspective of next-generation E-skin systems are presented.     

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.     

气动比例位置系统速度反馈与不完全微分PID控制

随着气动技术在各个领域的应用日渐广泛,气动比例位置控制系统优化已成为发展的必然趋势。文中建立了气动比例位置系统的数学模型,绘制系统Bode图并验证了其稳定性。通过引入速度反馈,并结合不完全微分型PID对气动比例位置系统的响应时间、精度和稳定性进行分析。仿真结果表明,引入速度反馈的不完全微分型PID校正的系统阶跃响应曲线,对比无校正、普通PID和不完全微分型PID对于阶跃信号的响应,其时间降低2.1 s,稳态误差下降0.22 mm,响应时间和稳态误差皆依次递减,响应过程更加平稳。引入速度反馈的不完全微分型PID校正的正弦追踪误差更小、稳定性更强、追踪效果更佳。该校正方法使系统响应速度大幅度提升的同时,显著增大了系统的精度并改善了系统的动静态特性。