Efficient Access Control for Wireless Sensor Data

Although very developed in many sectors (databases, filesystems), access control schemes are still somewhat elusive when it comes to wireless sensor networks. However, it is clear that many WSN systems—such as healthcare and automotive ones—need a controlled access to data that sensor nodes produce, given its high sensitivity. Enforcing access control in wireless sensor networks is a particularly difficult task due to the limited computational capacity of wireless sensor nodes. In this paper we present a full-fledged access control scheme for wireless sensor data. We enforce access control through data encryption, thus embedding access control in sensor data units. We also propose a lightweight key generation mechanism, based on cryptographic hash functions, that allows for hierarchical key derivation. The suggested protocol only relies on simple operations, does not require interactions between nodes and data consumers and has minimal storage requirements.

NDN中基于蚁群替换算法的邻居协作缓存管理策略

为提高NDN(命名数据网络)中的缓存利用率,提出了一种基于蚁群替换算法的邻居协作缓存管理(ACNCM)策略。首先将单节点的缓存替换问题,建模为0/1背包问题,并根据缓存数据的大小、使用频率以及邻居副本深度等信息定义本地存储内容的缓存价值,提出基于蚁群算法的缓存替换算法。然后利用邻域协作的思想,通过路由节点之间定期交换自身节点的缓存信息,对单个节点替换出去的缓存内容,选择邻居节点完成协作式缓存管理。实验结果表明,ACNCM策略在缓存命中率、网络开销和平均响应时延方面均优于现有方法。     

Strongly Consistent Access Algorithms for Wireless Data Networks

In wireless data networks such as the WAP systems, the cached data may be time-sensitive and strong consistency must be maintained (i.e., the data presented to the user at the WAP handset must be the same as that in the origin server). In this paper, we study the cached data access algorithms in such systems. Two caching algorithms are investigated. In Algorithm I, Pull-Each-Read, whenever a data access occurs, the client always asks the server whether the cached entry in the client is valid or not. In Algorithm II, Callback, the server always invalidates the cached entry in the client whenever an update occurs. Analytic models are proposed to evaluate the performance of these algorithms. Our studies show that Algorithm II outperforms Algorithm I if the data access rate is high and the access pattern is irregular. We also design an adaptive mechanism to effectively switch between the two algorithms to take advantages of both algorithms. We also apply the single-level cached data access algorithms for the multi-level cache hierarchy. Our study indicates that with appropriate arrangement, strongly consistent cached data access for wireless Internet (such as WAP) can be efficiently supported.Yuguang Fang received the B.S. and M.S. degrees in Mathematics from Qufu Normal University, Qufu, Shandong, China, in 1984 and 1987, respectively, a Ph.D degree from Department of Systems, Control and Industrial Engineering at Case Western Reserve University, Cleveland, Ohio, in January 1994, and a Ph.D degree from Department of Electrical and Computer Engineering at Boston University, Massachusetts, in May 1997.From 1987 to 1988, he held research and teaching positions in both Department of Mathematics and the Institute of Automation at Qufu Normal University. He held a post-doctoral position in Department of Electrical and Computer Engineering at Boston University from June 1994 to August 1995. From June 1997 to July 1998, he was a Visiting Assistant Professor in Department of Electrical Engineering at the University of Texas at Dallas. From July 1998 to May 2000, he was an Assistant Professor in the Department of Electrical and Computer Engineering at New Jersey Institute of Technology, Newark, New Jersey. From May 2000 to July 2003, he was an Assistant Professor in the Department of Electrical and Computer Engineering at University of Florida, Gainesville, Florida, where he has been an Associate Professor since August 2003. His research interests span many areas including wireless networks, mobile computing, mobile communications, automatic control, and neural networks. He has published over ninety papers in refereed professional journals and conferences. He received the National Science Foundation Faculty Early Career Development Award in 2001 and the Office of Naval Research Young Investigator Award in 2002. He is listed in Marquis Whos Who in Science and Engineering, Whos Who in America and Whos Who in World.Dr. Fang has actively engaged in many professional activities. He is a senior member of the IEEE and a member of the ACM. He is an Editor for IEEE Transactions on Communications, an Editor for IEEE Transactions on Wireless Communications, an Editor for ACM Wireless Networks, an Area Editor for ACM Mobile Computing and Communications Review, an Associate Editor for Wiley International Journal on Wireless Communications and Mobile Computing, and an Editor for IEEE Wireless Communications. He was an Editor for IEEE Journal on Selected Areas in Communications: Wireless Communications Series and the feature editor for Scanning the Literature in IEEE Wireless Communications (formerly IEEE Personal Communications). He has also actively involved with many professional conferences such as ACM MobiCom02, ACM MobiCom01, IEEE INFOCOM04, INFOCOM03, INFOCOM00, INFOCOM98, IEEE WCNC02, WCNC00 (Technical Program Vice-Chair), WCNC99, and International Conference on Computer Communications and Networking (IC3N98) (Technical Program Vice-Chair).Yi-Bing Lin received his BSEE degree from National Cheng Kung University in 1983, and his Ph.D. degree in Computer Science from the University of Washington in 1990. From 1990 to 1995, he was with the Applied Research Area at Bell Communications Research (Bellcore), Morristown, NJ. In 1995, he was appointed as a professor of Department of Computer Science and Information Engineering (CSIE), National Chiao Tung University (NCTU). In 1996, he was appointed as Deputy Director of Microelectronics and Information Systems Research Center, NCTU. During 1997-1999, he was elected as Chairman of CSIE, NCTU. His current research interests include design and analysis of personal communications services network, mobile computing, distributed simulation, and performance modeling. Dr. Lin has published over 150 journal articles and more than 200 conference papers.Dr. Lin is a senior technical editor of IEEE Network, an editor of IEEE Trans. on Wireless Communications, an associate editor of IEEE Trans. on Vehicular Technology, an associate editor of IEEE Communications Survey and Tutorials, an editor of IEEE Personal Communications Magazine, an editor of Computer Networks, an area editor of ACM Mobile Computing and Communication Review, a columnist of ACM Simulation Digest, an editor of International Journal of Communications Systems, an editor of ACM/Baltzer Wireless Networks, an editor of Computer Simulation Modeling and Analysis, an editor of Journal of Information Science and Engineering, Program Chair for the 8th Workshop on Distributed and Parallel Simulation, General Chair for the 9th Workshop on Distributed and Parallel Simulation. Program Chair for the 2nd International Mobile Computing Conference, Guest Editor for the ACM/Baltzer MONET special issue on Personal Communications, a Guest Editor for IEEE Transactions on Computers special issue on Mobile Computing, a Guest Editor for IEEE Transactions on Computers special issue on Wireless Internet, and a Guest Editor for IEEE Communications Magazine special issue on Active, Programmable, and Mobile Code Networking. Lin is the author of the book Wireless and Mobile Network Architecture (co-author with Imrich Chlamtac; published by John Wiley & Sons). Lin received 1998, 2000 and 2002 Outstanding Research Awards from National Science Council, ROC, and 1998 Outstanding Youth Electrical Engineer Award from CIEE, ROC. He also received the NCTU Outstanding Teaching Award in 2002. Lin is an Adjunct Research Fellow of Academia Sinica, and is Chair Professor of Providence University. Lin serves as consultant of many telecommunications companies including FarEasTone and Chung Hwa Telecom. Lin is an IEEE Fellow.     

无线传感器网络中数据存储与访问研究进展

 无线传感器网络集感知、计算和无线通信为一体,是以数据为中心的网络,因此数据存储与访问是无线传感器网络研究中的重要问题.本文围绕无线传感器网络以数据为中心这一条主线,对其中数据存储与访问的国内外研究进展进行了综述.首先概述了无线传感器网络中的数据存储与访问的概念与技术;然后详细探讨了各种数据存储策略,重点分析了分布式数据存储和信息中介;其次详细介绍了查询的分类、查询处理模型以及优化策略;最后对无线传感器网络中数据存储与访问技术进行了展望.     

无线接入技术及宽带IP无线移动接入网

介绍几种主要的无线接入技术。阐述宽带IP无线移动接入技术。     

Wireless Access

The next three years will see the introduction of packet data offerings on GSM. There will also be the emergence of new radio coding schemes to bring data rates up to 50 kbit/s. The introduction of 3rd Generation networks bringing the capability to deliver 500 kbit/s to the wide area will also be seen. For higher data rates closer to that of fixed networks (500 kbit/s to 16 Mbit/s), cordless technologies such as Bluetooth, DECT or HIPERLAN are evolving. Applications are currently limited to home or corporate use but with the right development these technologies could become suitable alternatives to the cellular network where very high data rates are needed. Additionally, the market for wireless systems offering a direct replacement to fixed wired access is exploding. Systems offering anything from 64 kbit/s to 50 Mbit/s are available and offer new entrants the potential to rapidly and economically establish direct access to their customers. Will this be the take-up of wireless data at last? This paper explores the scenarios that these technologies bring to the marketplace and how they will be making a difference. Wireless access has finally come of age.     

Cache consistency in Wireless Multimedia Sensor Networks

The production of cheap CMOS cameras, which are able to capture rich multimedia content, combined with the creation of low-power circuits, gave birth to what is called Wireless Multimedia Sensor Networks (WMSNs). WMSNs introduce several new research challenges, mainly related to mechanisms to deliver application-level Quality-of-Service (e.g., latency minimization). Such issues have almost completely been ignored in traditional WSNs, where the research focused on energy consumption minimization. Towards achieving this goal, the technique of cooperative caching multimedia content in sensor nodes can efficiently address the resource constraints, the variable channel capacity and the in-network processing challenges associated with WMSNs. The technological advances in gigabyte-storage flash memories make sensor caching to be the ideal solution for latency minimization. Though, with caching comes the issue of maintaining the freshness of cached contents. This article proposes a new cache consistency and replacement policy, called NICC, to address the cache consistency issues in a WMSN. The proposed policies recognize and exploit the mediator nodes that relay on the most “central” points in the sensor network so that they can forward messages with small latency. With the utilization of mediator nodes that lie between the source node and cache nodes, both push-based and pull-based strategies can be applied in order to minimize the query latency and the communication overhead. Simulation results attest that NICC outperforms the state-of-the-art cache consistency policy for MANETs.     

Efficient Cache Placement in Multi-Hop Wireless Networks

In this paper, we address the problem of efficient cache placement in multi-hop wireless networks. We consider a network comprising a server with an interface to the wired network, and other nodes requiring access to the information stored at the server. In order to reduce access latency in such a communication environment, an effective strategy is caching the server information at some of the nodes distributed across the network. Caching, however, can imply a considerable overhead cost; for instance, disseminating information incurs additional energy as well as bandwidth burden. Since wireless systems are plagued by scarcity of available energy and bandwidth, we need to design caching strategies that optimally trade-off between overhead cost and access latency. We pose our problem as an integer linear program. We show that this problem is the same as a special case of the connected facility location problem, which is known to be NP-hard. We devise a polynomial time algorithm which provides a suboptimal solution. The proposed algorithm applies to any arbitrary network topology and can be implemented in a distributed and asynchronous manner. In the case of a tree topology, our algorithm gives the optimal solution. In the case of an arbitrary topology, it finds a feasible solution with an objective function value within a factor of 6 of the optimal value. This performance is very close to the best approximate solution known today, which is obtained in a centralized manner. We compare the performance of our algorithm against three candidate cache placement schemes, and show via extensive simulation that our algorithm consistently outperforms these alternative schemes.     

一种实现无线数据网络差异化接入的方法

通过深层次分析无线网络资源控制过程和相关协议,以及吸取传统QoS业务模型和传统动态带宽分配方法 (DBA)的优点,发明了一种实现无线数据网络差异化接入的方法,可以实现在无线网络数据业务中结合不同用户等级与业务类型提供差异化服务。该发明专利申请已由国家知识产权局受理(申请号201110324444.7)。     

一种基于自回归预测的缓存替换算法

由于目前的web缓存替换算法多侧重于对用户的历史访问进行参考,缺乏对用户请求的预测.主要利用自回归模型可用于预测的特性,在基于访问时间间隔(LRU)替换算法的基础之上提出了一种基于自回归模型预测的web缓存替换算法,并进一步的在opnet网络仿真中进行了仿真验证.仿真结果表明:基于自回归预测的缓存替换算法相对于传统的缓存替换算法更能提高代理缓存的对象命中率和字节命中率.     

类有线的无线接入

提出了针对海量连接的、免调度和免资源分配的、类有线化的无线接入及资源共享方案。该方案为每一个参与传输的无线终端分配虚拟专用传输信道,终端按需在该虚拟传输信道进行数据传输。基于该方案的无线传输和有线传输仅仅在物理层使用不同介质进行,在此之上的各层可实现协议的统一化,有效降低无线传输的信令开销和相应的时延,降低无线传输的协议复杂度。     

无线接入网综述

1 接入网与无线接入网 整个通信网分为两部分:核心网(市话端局以上部分)与接入网(市话端局或远端模块以下的网络部分)。 接入网是指从本地交换局到用户之间的信息传送网。通信业务的发展对接入网提出了数字化、宽带化、灵活、可靠、易于管理等要求,希望一条用户线可     

Personalisierter Wireless Access

Ohne Zusammenfassung Nach einem Hauptvortrag, gehalten anl?sslich der Informationstagung Mikroelektronik ME 03 am 1. und 2. Oktober 2003 im Rahmen der VIET.     

浅谈无线接入技术

无线接入技术可分为模拟无一接入技术和数字无线接入技术,数字无线接入系统又有多种解决方案,包括数字直接扩频技术、ＧＳＭ、ＣＤＭＡ、ＤＥＣＴ、ＰＨＳ和ＳＣＤＭＡ等。     

无线接入技术及标准化

随着社会信息化的不断推进及通信技术快速发展,用户对信息业务的需求日益丰富,以互联网业务为代表的宽带多媒体数据业务正成为网络业务发展的主流。因此,构建宽带化、全业务、智能化的现代通信网络已成为大势所趋。     

基于内容预期价值的内容中心网络缓存替换策略

缓存替换技术是内容中心网络的研究内容之一。相对于海量的内容数据,缓存空间总是有限的,良好的缓存替换策略可以提高缓存收益。考虑到内容在将来被请求的概率越大,预期访问时间距离当前时刻越近,其留存价值就越大,提出了一种基于内容预期价值的替换策略。该方案通过考虑内容流行度和预期访问时间到当前时刻的时间距离,构建内容预期价值函数,并据此将价值最小的内容替换出去。仿真实验证明,该策略相对于传统的缓存替换策略,可以有效提高缓存命中率、降低请求跳数,提高网络性能。     

基于改进LRU替换策略的共享Cache划分

本文提出了一种基于改进的LRU替换策略划分最后一级共享Cache的算法,隔离了线程间的数据冲突,实现了改进的Cache替换策略,通过划分最后一级共享Cache也减少了访存延迟,提高了系统吞吐率.     

基于正交频分多址接入方式的宽带无线接入

文章介绍了目前IEEE 80 2 .16工作组提出的非视距环境中基于正交频分多址接入的宽带无线接入解决方案。     

Partition-Based Cache Replacement to Manage Shared L2 Caches

The Least recently used （LRU） replacement has been widely employed by on-chip shared caches. With the increase of cache associativity, the performance gap between LRU and theoretical optimal replacement algorithm is significant, motivating us to design alternative replacement algorithms to improve cache performance. We propose a Partltlon-based cache replace- ment （PCR） algorithm to manage multi-core shared L2 caches. PCR takes into consideration recency and fre- quency information of cache access, and cache resource interference among multiple competing applications. PCR is effective to flter out the less frequently reused blocks through a dynamic insertion/promotlon policy based on the target partitions~ and ensures that some fraction of the working set is retained in the cache to contribute to more hits. Our evaluation shows that PCR improves performance of an 8-core system by an average of 11.3% over LRU-based cache.