基于地理信息的WSN的路由协议的比较研究

作为无线传感网路由协议中的重要的一个分支,基于地理位置信息的路由协议在能量有效性、分布式控制、可扩展性等方面具有突出的优势。为了更好的对基于地理位置信息路由协议的研究,本文对GEAR、GRID和GEM三个具有代表性的地理位置信息路由协议进行了详细的介绍。最后,总结了三种基于地理位置信息的路由协议在应用方面的优缺点,并提出了值得参考的研究发展方向。     

移动自组网中一种洞椭圆化的避洞路由协议

基于地理位置信息的路由协议具有很好的可扩展性。然而,当源节点和目的节点之间存在洞时,该类路由协议可能遇到局部最优的问题。针对此问题,提出了一种基于洞椭圆化的避洞路由协议。该协议通过把洞规则化为一个椭圆,并把洞的信息向外局部广播,从而有效地解决了该问题。模拟结果表明该路由协议具有路由延迟小、路径短等特点。     

基于位置的Ad hoc网络路由协议研究

基于位置的Ad hoc网络路由协议利用节点地理位置信息指导数据包的转发,具有可扩展性强,路由效率高等优点。分析了Ad hoc网络中基于位置的路由协议以及位置信息服务,对几种协议进行了分析比较,并指出了基于位置的路由协议的研究重点。     

基于地理位置的Ad Hoc路由协议

Ad Hoc网络中基于地理位置信息的路由面临一个贪婪转发策略失败的本地最小问题,提出了一种基于地理位置信息的Ad hoc路由协议GAR。在GAR协议中,根据节点拓扑变化,划分路由范围,进一步缩小了路由范围,提出了利用斜率转发策略克服了路由算法解决本地最小问题所带来的复杂性。在GAR协议的基础上进一步改进,提出了GALMR协议,该协议通过标记节点发现过程,减少路由跳数,提高算法的执行效率。理论分析和实验结果显示GALMR算法具有较高的数据分组抵达率和较低的平均端到端延迟。     

一种城市环境下的地理位置路由策略改进方法

在城市环境下的VANET应用场景中, 传统的基于地理位置信息的路由算法如GPSR等存在一些问题, 本文在此基础上提出一个改进的路由协议, 通过对车辆节点网络传输负荷以及所在路段方向等状态信息进行检测, 并将此作为路由转发选择依据. 新协议选择传输延时小并且路由健壮性较强的路径进行数据转发, 有效地提高了城市环境下的路由传递效率. NS2仿真结果表明新协议具有较好的性能.     

无线传感器网络通信空洞分析

本文简述无线传感器网络近代发展的情况。详细介绍了以地理位置信息为基础的贪婪路由算法。分析了现有的贪婪算法存在的不足,着重讨论了贪婪路由算法中通信空洞现象各种不同的解决方法。基于以上分析对地理位置信息在无线传感器网络路由协议的发展提出看法。     

三维水声传感器网络中基于网络编码的地理位置路由协议

针对三维水声传感器网络数据传输效率低、能量消耗大的问题,提出一种基于网络编码的地理位置路由协议。该协议在路由过程中根据邻居节点的地理位置来选择路由候选节点,并采用网络编码的方式进行数据传输,确保数据包在链路丢包率较高的情况下也可以正确、高效地转发,并且有效降低网络中冗余数据包重传造成的能量消耗。仿真结果表明,基于网络编码的地理位置路由协议可以在提高数据包传送率的同时,有效降低网络能量消耗。     

水下传感网络能量均衡与时延优化深度路由协议

水下传感器节点的精准位置信息很难获取,因此基于地理位置的水下传感器网络路由协议在水下三维空间中很难广泛应用,基于深度信息的路由协议DBR(Depth-Based Routing)只需要掌握节点深度信息就可以实现有效的数据转发,克服了需要精确地理位置的约束,但是传统 DBR协议采用了洪泛传播机制,增加了水下传感器网络的冗余数据包,导致能量消耗过多且分布不均衡,从节点能量耗费均衡和数据包传输时延优化的角度,提出了基于水下传感器节点能量均衡与延时优化的DBR优化改进策略,根据传感器邻居节点的深度值以及剩余能量水平决定各个邻居节点的转发概率。仿真结果验证了改进后的深度路由协议在数据传输成功率和能耗均衡性能等方面均优于传统的DBR协议。     

无线传感器网络中一种基于行进启发的地理位置路由

为了节省传感器节点有限的能量,针对无线传感器网络"多对一"通信的特点,提出了一种新的、基于地理位置信息的路由协议--基于行进启发的地理位置路由,该协议不需要等到数据包遇到"空洞"时才采取措施,而是在数据包离空洞还有一定距离时就提前绕开它,从而少走了弯路,减少了能量消耗.模拟研究表明,采用该协议建立路由的过程快速、开销小,数据传送的路径长度短,可适用于大规模的无线传感器网络,     

无线传感网络中协作分集路由协议的研究

在无线传感网络系统中,协作分集是对抗多径传播引起的信道衰落的一种有利的方法,但是目前大多数协作分集的研究集中在物理层,协作引入后对于网络的更高层的影响并没有很好的展开讨论。基于协作分集中协作路由协议是一个新的研究领域,介绍了协作分集以及GeRaF和GnRaF两种协作路由协议。这两种协议摒除了传统路由协议依靠拓扑信息和路由表的弊端而是只根据节点自身及周围节点的地理位置信息及角度信息的新型路由协议。     

基于Visual FoxPro环境AeCESS数据库操作的实现

在Visual FoxPro中使用ACCESS数据库,能够克服其自奄存在的数据库、数据表与索引文件分离、数据表安全性不高等不利因素,较好地发挥二者在数据库管理与编程方酗的优势。鉴于这方面的资料较少,系统地阐述Visual FoxPm环境下ACCESS数据库的操作方法,实现在Visual FoxPro中ACCESS数据库的建立、压缩与修复;数据表的建立、结构与记录的维护;Visual FoxPro数据库与ACCESS数据库的相互转换、Visual FaxPro中通用字段与ACCESS中OLE字段的数据转换等方法是很多用户的客观需求。用Visual FoxPro编程方式全面操纵ACCESS数据库具有重要的理论与应用价值。     

Stability of nonlinear hybrid dynamical systems with time delay via sum of squares decomposition

Considering an infinite number of eigenvalues for time delay systems, it is difficult to determine their stability. We have developed a new approach for the stability test of time delay nonlinear hybrid systems. Construction of Lyapunov functions for hybrid systems is generally a difficult task, but once these functions are found, stability’s analysis of the system is straight-forward. In this paper both delay-independent and delay-dependent stability tests are proposed, based on the construction of appropriate Lyapunov-Krasovskii functionals. The methodology is based on the sum of squares decomposition of multivariate polynomials and the algorithmic construction is achieved through the use of semidefinite programming. The reduction techniques provide numerical solution of large-scale instances; otherwise they will be computationally infeasible to solve. The introduced method can be used for hybrid systems with linear or nonlinear vector fields. Finally simulation results show the correctness and validity of the designed method. Recommended by Editorial Board member Young Soo Suh under the direction of Editor Jae Weon Choi. The authors wish to express their thanks to Dr. A. Papachristodoulou and Dr. M. Peet for their helpful comments and suggestions. Mohammad Ali Badamchizadeh was born in Tabriz, Iran, in December 1975. He received the B.S. degree in Electrical Engineering from University of Tabriz in 1998 and the M.Sc. degree in Control Engineering from University of Tabriz in 2001. He received the Ph.D. degree in Control Engineering from University of Tabriz in 2007. He is now an Assistant Professor in the Faculty of Electrical and Computer Engineering at University of Tabriz. His research interests include Hybrid dynamical systems, Stability of systems, Time delay systems, Robot path planning. Sohrab Khanmohammadi received the B.S. degree in Industrial Engineering from Sharif University, Iran in 1977 and the M.Sc. degree in Automatic from University Paul Sabatie, France in 1980 and the Ph.D. degree in Automatic from National University, ENSAE, France in 1983. He is now a Professor of Electrical Engineering at University of Tabriz. His research interests are Fuzzy control, Artificial Intelligence applications in control and simulation on industrial systems and human behavior. Gasem Alizadeh was born in Tabriz, Iran in 1967. He received the B.S. degree in Electrical Engineering from Sharif University, Iran in 1990 and the M.Sc. degree from Khajeh Nasir Toosi University, Iran in 1993 and the Ph.D. degree in Electrical Engineering from Tarbiat Modarres University, Iran in 1998. From 1998, he is a Member of University of Tabriz in Iran. His research interests are robust and optimal control, guidance, navigation and adaptive control. Ali Aghagolzadeh was born in Babol, Iran. He received the B.S. degree in Electrical Engineering in 1985 from University of Tabriz, Tabriz, Iran, and the M.Sc. degree in Electrical Engineering in 1988 from the Illinois Institute of Technology, Chicago, IL. He also attended the School of Electrical Engineering at Purdue University in August 1998 where he was also employed as a part-time research assistant and received the Ph.D. degree in 1991. He is currently an Associate Professor of Electrical Engineering at University of Tabriz, Tabriz, Iran. His research interests include digital signal and image processing, image coding and communication, computer vision, and image analysis.     

跨设备交互场景下参照域构建方法的设计策略研究

针对智能家居中跨设备交互的内容传输问题,从参照类型和工件数量 2 个方面定义交互的可见性, 并在此基础上提出了 4 种参照域构建方法(物理的,物理耦合的,数字的,自然的)。通过“绿野仙踪”实验探究 4 种方法在单一任务和主次任务场景下对用户体验的影响,实验结果表明,不同方法在同一场景,以及同一方法 在不同场景的用户体验有差异。得出 2 个方面结论：①方法的差异性,物理的方法是高效而有趣的,物理耦合的 方法最有趣但实行性较低,数字的方法最实用但也是常规的,自然的方法在主次任务场景下最实用;②场景的差 异性,主次任务场景中用户重点关注实用性,而用户在单一任务场景中既关注实用性也对享乐性提出了要求。     

Methods of system development in Finland

Interest in the use of different methodologies, methods and tools for information systems analysis and design has been increasing for the last decade in Finland. This has resulted in the founding of a special interest group in systems analysis and design within the Finnish Data Procesing Association and in its making a survey of the methods and tools in use in Finland in 1980. This survey was in the form of a questionnaire mailed to the company members of the association. The results of the survey show a wide use of different tools in the design and implementation of information systems. In the analysis phase, there seems to be a need for more and better methods and tools. In 1980 several companies began to use new methodologies, methods and tools in the field; the most common are: the Swedish ISAC, Jackson's JSP, and the data dictionary.     

Design and analysis of the Dual-Torus Network

In this paper, we propose a new topology called theDual Torus Network (DTN) which is constructed by adding interleaved edges to a torus. The DTN has many advantages over meshes and tori such as better extendibility, smaller diameter, higher bisection width, and robust link connectivity. The most important property of the DTN is that it can be partitioned into sub-tori of different sizes. This is not possible for mesh and torus-based systems. The DTN is investigated with respect to allocation, embedding, and fault-tolerant embedding. It is shown that the sub-torus allocation problem in the DTN reduces to the sub-mesh allocation problem in the torus. With respect to embedding, it is shown that a topology that can be embedded into a mesh with dilation δ can also be embedded into the DTN with less dilation. In fault-tolerant embedding, a fault-tolerant embedding method based on rotation, column insertion, and column skip is proposed. This method can embed any rectangular grid into its optimal square DTN when the number of faulty nodes is fewer than the number of unused nodes. In conclusion, the DTN is a scalable topology well-suited for massively parallel computation. Sang-Ho Chae, M.S.: He received the B.S. in the Computer Science and Engineering from the Pohang University of Science and Technology (POSTECH) in 1994, and the M.E. in 1996. Since 1996, he works as an Associate Research Engineer in the Central R&D Center of the SK Telecom Co. Ltd. He took part in developing SK Telecom Short Message Server whose subscribers are now over 3.5 million and Advanced Paging System in which he designed and implemented high availability concepts. His research interests are the Fault Tolerance, Parallel Processing, and Parallel Topolgies. Jong Kim, Ph.D.: He received the B.S. degree in Electronic Engineering from Hanyang University, Seoul, Korea, in 1981, the M.S. degree in Computer Science from the Korea Advanced Institute of Science and Technology, Seoul, Korea, in 1983, and the Ph.D. degree in Computer Engineering from Pennsylvania State University, U.S.A., in 1991. He is currently an Associate Professor in the Department of Computer Science and Engineering, Pohang University of Science and Technology, Pohang, Korea. Prior to this appointment, he was a research fellow in the Real-Time Computing Laboratory of the Department of Electrical Engineering and Computer Science at the University of Michigan from 1991 to 1992. From 1983 to 1986, he was a System Engineer in the Korea Securities Computer Corporation, Seoul, Korea. His major areas of interest are Fault-Tolerant Computing, Performance Evaluation, and Parallel and Distributed Computing. Sung Je Hong, Ph.D.: He received the B.S. degree in Electronics Engineering from Seoul National University, Korea, in 1973, the M.S. degree in Computer Science from Iowa State University, Ames, U.S.A., in 1979, and the Ph.D. degree in Computer Science from the University of Illinois, Urbana, U.S.A., in 1983. He is currently a Professor in the Department of Computer Science and Engineering, Pohang University of Science and Technology, Pohang, Korea. From 1983 to 1989, he was a staff member of Corporate Research and Development, General Electric Company, Schenectady, NY, U.S.A. From 1975 to 1976, he was with Oriental Computer Engineering, Korea, as a Logic Design Engineer. His current research interest includes VLSI Design, CAD Algorithms, Testing, and Parallel Processing. Sunggu Lee, Ph.D.: He received the B.S.E.E. degree with highest distinction from the University of Kansas, Lawrence, in 1985 and the M.S.E. and Ph.D. degrees from the University of Michigan, Ann Arbor, in 1987 and 1990, respectively. He is currently an Associate Professor in the Department of Electronic and Electrical Engineering at the Pohang University of Science and Technology (POSTECH), Pohang, Korea. Prior to this appointment, he was an Associate Professor in the Department of Electrical Engineering at the University of Delaware in Newark, Delaware, U.S.A. From June 1997 to July 1998, he spent one year as a Visiting Scientist at the IBM T. J. Watson Research Center. His research interests are in Parallel, Distributed, and Fault-Tolerant Computing. Currently, his main research focus is on the high-level and low-level aspects of Inter-Processor Communications for Parallel Computers.     

生物组织光声成像技术综述

光声成像是一种低功率、非电离的成像方式,既具有声学方法对深层组织成像分辨率高的优点,又具有光学方法在功能成像、分子成像方面具有高对比度的优势。本文回顾了近年来,光声成像技术在生物医学领域的研究进展,介绍了光声成像的基本成像原理。以此为基础,本文介绍了光声成像的两种主要成像方案：光声断层成像和光声显微镜,并且讨论了光声成像在获取生物组织化学成分信息和微结构信息方面的优越性;最后,本文对光声成像技术的优点和应用前景进行了总结。     

利用MODIS EVI时间序列数据分析福建省植被变化(2000~2017年)

以全国森林覆盖率最高的福建省为研究对象,利用2000~2017年夏季的MODIS EVI植被指数数据和气象与非气象因子进行协同分析,以揭示近17年福建植被的时空变化及其影响因子。结果表明:研究期内福建的EVI均值整体上升,从2000年的0.454上升至2017年的0.505,17 a间上升了11.2%,表明福建省的植被整体处于变好的状态,且在中部和西南部的变化最明显。相关分析表明,在研究期内,气象因子(气温和降水)对EVI变化的影响不显著,植被的变好主要为非气象因子的作用。EVI的提高主要得益于2003年福建省建设生态省后森林覆盖率的提高,并和2012年开始的水土流失治理有明显关系,这说明人类活动的积极作用对福建植被的变好起到了关键的作用。     

INTRODUCTION TO THE SPECIAL ISSUE ON CASE-BASED REASONING IN THE HEALTH SCIENCES

There has been an explosion of interest in health sciences applications of case-based reasoning (CBR), not only in the traditional CBR in medicine domain, but also in bioinformatics, enabling home health-care technologies, CBR integration, and synergies between CBR and knowledge discovery. This special issue features the best papers from the third workshop on CBR in the health sciences, held at ICCBR-05 in Madrid. It is the third in a series of exciting workshops, the first two of which were held at ICCBR-03, in Trondheim, Norway, and at ECCBR-04, in Madrid, Spain. The nine high-quality papers introduced here represent the research and experience of twenty-two authors working in eight different countries on a wide range of problems and projects. These papers illustrate some of the major trends of current research in CBR in the health sciences, and represent overall an excellent sample of the most recent advances of CBR in the health sciences.     

空域频域相结合的唇型篡改检测方法

近年来,社交网络中的“换脸”视频层出不穷,对说话者进行唇型篡改是其中的视频代表之一,这给大众生活增添娱乐的同时,对于网络空间中的个人隐私、财产安全也带来了不小隐患。大多数唇型篡改检测方法在无损条件下取得了较好的表现,但广泛存在于社交媒体平台、人脸识别等场景中的压缩操作,在节约像素和时间冗余的同时,会对视频质量造成影响,破坏空域上像素与像素、帧与帧之间的连贯完整性,导致其检测性能的下降,从而引发对真实视频的错判情况。当空域信息无法提供足够有效的特征时,能够抵抗压缩干扰的频域信息就自然而然地成为重点研究对象。针对这一问题,通过分析频率信息在图像结构和梯度反馈上的优势,提出了空域频域相结合的唇型篡改检测方法,有效利用空域、频域信息的各自特点。对于空域上的唇型特征,设计了自适应提取网络和轻量级的注意力模块;对于频域上的频率特征,设计了不同分量的分离提取与融合模块。随后,通过对空域上的唇型特征和频域上的频率特征进行有侧重的融合,保留更多关键纹理信息。此外,在训练中设计细粒度约束,分开真假唇型特征类间距离的同时,拉近类内距离。实验结果表明,得益于频率信息,所提方法能有效改善压缩情况下的检测准确性,并具备一定的迁移性。另外,在对核心模块开展的消融实验中,相关结果验证了频率分量对于抗压缩的有效性,以及双重损失函数在训练中的约束作用。