搜索引擎Web API框架设计研究

传统的基于网页方式的搜索引擎服务不能很好地满足用户个性化的需求,搜索引擎Web API概念的提出较好的解决了这一问题.本文提出了一种基于SOAP和WSDL标准的搜索引擎Web API的构架模型.该构架模型的接口由五大部分组成,内容涵盖了用户自定义搜索条件的各项参数以及返回结果剥离所需的各项参数.采用SOAP和WSDL标准保证了该接口跨语言、跨平台特性.文章系统地介绍了框架的构造、功能,并对接口方法以及参数定义进行了详细的说明.     

智能型交通信号控制机的研制

介绍一种技术性能比较先进的交通信号控制机,这种信号机不仅能够自动地进行多时段控制,还可以接入网络实现在线控制;电路设计采用模块式的电路结构,可根据用户的功能需要增减模块电路。     

后备路径在自组网AODV协议中的应用

研究了后备路由策略在自组网AODV协议中的应用。通过仿真实验证明在不增加控制信息个数的条件下,后备路由策略能有效提高AODV协议的数据平均递交率。     

SNMPv3网络安全管理研究

提出计算机网络管理面临的安全威胁，分析了简单网络管协议SNMPv3及其基于用户的安全模型USM的安全机制，最后总结SNMPv3有待考虑的问题并总体评价了SNMPv3的安全性。     

一种基于能量优化的无线传感网络自适应组织结构和协议

本文提出了一种新的无线微传感器网络协议和组织结构ALEP。与传统的无线微传感器网络协议相比，ALEP更加充分地考虑到实际应用，将一种高效能量控制算法引入组网协议，提高了网络的能量利用率，显著延长了无线网络的生命周期，增强了网络的健壮性。通过对ALEP协议进行OPNET仿真，结果显示该协议与传统模式的无线微传感器网络协议相比，在传送相同的数据量的条件下有更高效的能量特性和信息传输特性。     

移动代理技术在Ad Hoc无线网络中的应用研究

Ad Hoc无线网络是一组具有路由和转发功能的移动节点组成的一个多跳的临时性自治系统,是一种无中心的无线网络。现有的主动路由协议或者按需路由协议都不能很好地满足Ad Hoc网络的需要。介绍了Ad Hoc无线移动网络和移动代理技术。在分析了现有的2种路由协议后,提出了在按需路由协议中加入移动代理技术来增强Ad Hoc无线网络的性能。在这些结果的基础上,提出了移动代理通信协议。     

区分业务及其在IP城域网的实施

传统的尽力而为的转发机制由于Internet的飞速发展,已经不能满足用户的要求。为此,对区分业务方案的具体系结构及实现环节作了详细的介绍,并讨论了其在IP城域网的实施。与其它机制相比,区分业务实现简单、系统开销少,能在骨干网中有效地保证服务质量。     

Comparing Algorithms for Sorting with <Emphasis Type="Italic">t</Emphasis> Stacks in Series

We show that the left-greedy algorithm is a better algorithm than the right-greedy algorithm for sorting permutations using t stacks in series when t > 1. We also supply a method for constructing some permutations that can be sorted by t stacks in series and from this get a lower bound on the number of permutations of length n that are sortable by t stacks in series. Finally we show that the left-greedy algorithm is neither optimal nor defines a closed class of permutations for t > 2.AMS Subject Classification: 05A05, 68R05, 68W01.     

新世纪电信：更远的想象

从上世纪最后15年到现在,电信的发展速度大大超过了过去00年的进步。在如此快在发展速度的基础上,人们可以想象出未来电信世界的大致情况。在未来,全光网络连接世界各个角落;个性化服务充满市场;移动电话成了人们的网络伴侣;充裕的带宽给人们带来了更多的服务和应用,但另一方面,移动通信却可能成了新世纪的“烟草工业”;IP统治了网络之后,人们有可能面临着又一轮选择。     

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.