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。     

Distribution and Variation of Glacier Velocity in Himalayas based on ALOS PALSAR

Based on the 12 scenes ALOS PALSAR data from December 2007 to February 2010,combined with SRTM,we estimated the glacier velocityof the Himalayasin three periods by feature tracking method.The results show that glacier velocity of the winter of 2007,the summer of 2009 and the winter of 2009 were between 0~300 m·a^-1,and accumulation area of the glacier have obvious movement only in summer,butthe movement of the glacier tongue is obviousin any season.Long tongue glacier velocity decreasesslowlyalong the mainstream line,while the short tongue glacier velocity fluctuatesalong the mainstream line,and even increases.The glacier in east aspecthas the largest velocity.The glaciervelocity in southeast aspect and the southwest aspect are second,and glacier velocity is minimum in the north aspect.In addition to climatic factors,it also closely relates to terrain factors.In terms of the slope of the four aspects,the north aspecthas the smallest slope,andit is one of the main causes of the smallest glacier velocity in the north aspect.There is an inter-annual variation of glaciers,that is,mean velocity of glaciers increases in winter,and the increased velocities are between -5~18 m·(2a).The glacier with small areavaries greatly,and the glacier with large area varies little.Meanwhile,the glacier velocity also has seasonal variation.The overall velocity in summer is larger than that in winter.The velocity in mainstream line fluctuates strongly in summer,and there are many peaks,but velocity in winteris gentle.However,the seasonal variation of the mean velocity in mainstream line is not obvious.The inter-annual variation and seasonal variation of the four typical glacier velocities are similar to those of the glaciers in the study area.There is a close relationship between velocity and climate and the shape of the glacier.The characteristics of glacier advance and retreat are not obvious,and the glaciers in the study area are in equilibrium.     

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.     

中国图像工程：2021

本文是关于中国图像工程的年度文献综述系列之二十七。为了使国内广大从事图像工程研究和图像技术应用的科技人员能够较全面地了解国内图像工程研究和发展的现状,能够有针对性地查询有关文献,且向期刊编者和作者提供有用的参考,对2021年度图像工程相关文献进行了统计和分析。具体从国内15种有关图像工程重要中文期刊在2021年发行的所有154期上所发表的学术研究和技术应用文献(共2958篇)中,选取出所有属于图像工程领域的文献(共833篇),并根据各文献的主要内容将其分别归入图像处理、图像分析、图像理解、技术应用和综述评论5个大类,然后进一步分入23个专业小类(与前16年相同),并在此基础上分别进行了各期刊各类文献的统计和分析。根据对2021年统计数据的分析可以看出：图像分析方向当前得到了最多的关注,其中目标检测和识别、图像分割和边缘检测、人体生物特征提取和验证等都是研究的焦点。另外,遥感、雷达、声呐、测绘以及生物、医学等领域的图像技术开发和应用最为活跃。总的来说,中国图像工程在2021年的研究深度和广度还在继续提高和扩大,仍保持了快速发展的势头。综合27年的统计数据还为读者提供了更全面和更可信的各个研究方向发展趋势的信息。     

差分隐私的高维数据发布研究综述

大数据时代的到来,使得信息量暴增的同时,数据维度也呈现几何式增长。在保护用户隐私的前提下,如何充分挖掘高维数据的可用信息,成为了大数据发布领域的研究热点和难点。差分隐私作为一种强大的隐私保护模型,被越来越多地应用到高维数据发布中。本文归纳了差分隐私及其相关方法在高维数据发布的应用,重点分析了差分隐私和特征降维、特征抽取、贝叶斯网络、树模型以及最新提出的粗糙集和随机投影等方法在高维数据发布中结合应用的优缺点,梳理了各个方法在高维数据方面的应用和对比,最后对未来差分隐私在高维数据发布中的应用方向进行了展望。     

导弹机内测试技术的国内外发展现状

导弹武器系统的综合测试是产品研发和使用中的重要保障技术,在武器系统的全寿命周期中扮演着越来越重要的角色；机内测试技术是提高系统测试性的关键方法之一,作为一种能够在设备或系统等测试单元内部自检的技术,机内测试在导弹测试领域中被广泛使用；介绍了国内外对机内测试的基本定义、特点、作用、虚警及抑制等发展的现状,并主要聚焦于导弹武器系统中的机内测试案例；针对机内测试在导弹领域应用中存在的问题,讨论了满足未来新一代导弹测试性需求的可能途径,并对机内测试技术未来的发展趋势进行了探讨和展望。     

Himawari-8气溶胶产品的验证及应用

为准确分析中国地区气溶胶空间分布与时间变化特征规律,首先利用中国地区9个AERONET（Aerosol Robotic Network）地基站点观测资料对新一代静止气象卫星Himawari-8气溶胶光学厚度（Aerosol Optical Depth, AOD）产品数据进行一致性验证,并在此基础上选取2015年7月至2018年4月Himawari-8逐小时AOD数据分析了中国地区气溶胶光学厚度时空变化特征。结果表明：①Himawari-8 AOD与AERONET AOD之间相关性很高,9个站点的相关系数R在0.64 ~ 0.91之间,拟合曲线斜率k的范围为0.57 ~ 0.68。②Himawari AOD产品与AERONET AOD的相关性在中午时段较其他时段相对较低;北方地区Himawari-8 AOD冬季反演效果与夏季相比较差,南方地区则相反。③中国地区年平均AOD呈东高西低分布,春、夏两季AOD明显高于秋、冬两季,其中夏季最高,春季次之;地区间AOD月变化差异也较大;大部分地区AOD日变化呈现先下降后上升再下降的趋势,AOD最高值出现在午后14 ~ 16时,最低值出现在18时。研究结果为了解中国地区大气气溶胶的时空变化规律和全天时的大气污染监测方法提供新的参考。     

Abstracting Vehicle Shape and Kinematic Constraints from Obstacle Avoidance Methods

Most obstacle avoidance techniques do not take into account vehicle shape and kinematic constraints. They assume a punctual and omnidirectional vehicle and thus they are doomed to rely on approximations when used on real vehicles. Our main contribution is a framework to consider shape and kinematics together in an exact manner in the obstacle avoidance process, by abstracting these constraints from the avoidance method usage. Our approach can be applied to many non-holonomic vehicles with arbitrary shape. For these vehicles, the configuration space is three-dimensional, while the control space is two-dimensional. The main idea is to construct (centred on the robot at any time) the two-dimensional manifold of the configuration space that is defined by elementary circular paths. This manifold contains all the configurations that can be attained at each step of the obstacle avoidance and is thus general for all methods. Another important contribution of the paper is the exact calculus of the obstacle representation in this manifold for any robot shape (i.e. the configuration regions in collision). Finally, we propose a change of coordinates of this manifold so that the elementary paths become straight lines. Therefore, the three-dimensional obstacle avoidance problem with kinematic constraints is transformed into the simple obstacle avoidance problem for a point moving in a two-dimensional space without any kinematic restriction (the usual approximation in obstacle avoidance). Thus, existing avoidance techniques become applicable. The relevance of this proposal is to improve the domain of applicability of a wide range of obstacle avoidance methods. We validated the technique by integrating two avoidance methods in our framework and performing tests in the real robot. Javier Minguez received the physics science degree in 1996 from the Universidad Complutense de Madrid, Madrid, Spain, and the Ph.D. degree in computer science and systems engineering in 2002 from the University of Zaragoza, Zaragoza, Spain. During his student period, in 1999 he was a research visitor in the Robotics and Artificial Intelligence Group, LAASCNRS, Toulouse, France. In 2000, he visited the Robot and ComputerVision Laboratory (ISR-IST), Technical University of Lisbon, Lisbon, Portugal. In 2001, he was with the Robotics Laboratory, Stanford University, Stanford, USA. He is currently a fulltime Researcher in the Robot, Vision, and Real Time Group, in the University of Zaragoza. His research interests are obstacle avoidance, motion estimation and sensor-based motion systems for mobile robots. Luis Montano was born on September 6, 1958 in Huesca, Spain. He received the industrial engineering degree in 1981 and the PhD degree in 1987 from the University of Zaragoza, Spain. He is an Associate Professor of Systems Engineering and Automatic Control at the University of Zaragoza (Spain). He has been Head of the Computer Science and Systems Engineering Department of the University of Zaragoza. Currently he is the coordinator of the Production Technologies Research in the Aragon Institute of Engineering Research and of the Robotics, Perception and Real Time group of the University of Zaragoza. He is principal researcher in robotic projects and his major research interests are mobile robot navigation and cooperative robots. José Santos-Victor received the PhD degree in Electrical and Computer Engineering in 1995 from Instituto Superior Técnico (IST - Lisbon, Portugal), in the area of Computer Vision and Robotics. He is an Associate Professor at the Department of Electrical and Computer Engineering of IST and a researcher of the Institute of Systems and Robotics (ISR), at the Computer and Robot Vision Lab - VisLab. (http://vislab.isr.ist.utl.pt) He is the scientific responsible for the participation of IST in various European and National research projects in the areas of Computer Vision and Robotics. His research interests are in the areas of Computer and Robot Vision, particularly in the relationship between visual perception and the control of action, biologically inspired vision and robotics, cognitive vision and visual controlled (land, air and underwater) mobile robots. Prof. Santos-Victor is an IEEE member and an Associated Editor of the IEEE Transactions on Robotics.     

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。     

Towards a Smarter Meeting Record—Capture and Access of Meetings Revisited

Multimedia records of meetings contain a rich amount of project information. However, finding detailed information in a meeting record can be difficult because there is no structural information other than time to aid navigation. In this paper we survey and discuss various ways of indexing meeting records by categorizing existing approaches along multiple dimensions. We then introduce the notion of creating indices based upon user interaction with domain-specific artifacts. As an example to illustrate the use of domain-specific artifacts to create meaningful pointers into the meeting record, we describe capture and access in a prototype system that supports general meeting artifacts. Werner Geyer is a Research Staff Member at the IBM T.J. Watson Research Lab in Cambridge, Massachusetts, in the Collaborative User Experience Group (CUE). He is leading research projects in the areas of activity-centric collaboration, ad hoc collaboration, and virtual meetings. His research focuses on the intersections of egocentric vs. public, informal vs. formal, unstructured vs. structured types of collaboration. Before joining CUE, Werner was a Post Doc at IBM Research in New York where he worked on new web-based team support technologies and on capture and access of distributed meetings. He holds a Ph.D. in Computer Science from the University of Mannheim, Germany. He also earned a M.S. in Information Technology, which combines Computer Science and Business Administration, from the University of Mannheim. Heather Richter is an Assistant Professor in the Department of Software and Information Systems at the University of North Carolina at Charlotte. She received her Ph.D. in Computer Science from the Georgia Institute of Technology in 2005, and her B.S. in Computer Science from Michigan State University in 1995. Her research interests are in the areas of Human Computer Interaction, Computer Supported Cooperative Work, Ubiquitous Computing, and Software Engineering. Gregory D. Abowd is an Associate Professor in the College of Computing at the Georgia Institute of Technology. He leads the Ubiquitous Computing Research Group in examining issues involved in building and evaluating ubiquitous computing applications that impact our everyday lives. Dr. Abowd initiated, and now co-directs, the Aware Home Research Initiative at Georgia Tech. He is an Associate Editor for the Human Computer Interaction Journal and the IEEE Pervasive Computing Magazine. He received a B.S. in Mathematics in 1986 from the University of Notre Dame and the degrees of M.Sc. in 1987 and D.Phil in 1991 in Computation from Oxford University.     

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.