摘要
无线传感器网络(WSNs)是新一代的传感器网络,综合了传感器技术、嵌入式计算技术、现代网络及无线通信技术、分布式信息处理技术等。传感器信息获取技术已经从单一化渐渐向集成化、微型化和网络化方向发展。无线传感器网络的出现和发展实现了物理世界、计算机世界以及人类社会三元世界的连通,并将会带来一场信息革命。
尽管针对无线传感器网络的某些技术难点问题进行了许多的技术革新,但是困扰无线传感器网络发展的关键问题是到目前为止还没有一个统一的、标准的网络体系结构。建立一个通用、抽象的体系结构是设计无线传感器网络的基础和前提。在该体系结构框架下,针对无线传感器网络中的能量有效、网络拓扑、网络安全等问题才有可能进一步的规范和标准化。
由于传感器节点的能量、处理能力、存储容量和通信带宽都十分有限,其能量问题是整个网络的核心问题,直接决定了传感器网络的生命周期。这使得在传感器网络中能量优化显得十分重要,几乎包括从底层的物理层到应用层的所有层面都要考虑其能量有效性问题。
其中,动态能量管理(DPM)是一种重要的节能思想。采用合理有效的动态能量管理策略有利于减少无线传感器网络的能量消耗,从而延长网络的生命周期。另外,在满足全覆盖和连通性前提下,如何达到网络的能量有效性是传感器网络研究中的另一个重要问题。
围绕传感器网络的能量问题,本文的主要研究有以下几个方面:
1.提出了一个基于立体跨层(CCL)的传感器网络体系结构。其基本思想是将OSI参考模型的分层思想与无线传感器网络的跨层设计相结合。一方面,CCL具有传统分层设计的优点;另一方面,它又满足传感器网络某些跨层服务的需要,如能量管理、定位、同步、安全以及移动管理和任务管理等。在CCL的设计中,无线传感器网络结构被分成了物理层、传感器服务协议层(SSP)和应用层。其中,传感器服务协议(SSP)层类似Culler所提出的“细腰-SP”概念。SSP可以看作是整个网络中的一个中间件服务层的通用抽象,同时对网络中的服务进行协同调配。所有这些服务都能够被整个网络的各层所访问,而不是封装成一个独立的层,仅仅为其上或其下的层所见。
2.针对Sinha提出的动态能量管理策略和算法进行了修改,考虑了节点电池的能量状态和唤醒节点所需额外能量等多种因素。这些因素直接决定了节点的休眠状态和休眠周期。同时,针对时间阈值条件(即休眠节点在休眠状态所保持的最短时间)进行了修正。模拟实验表明,在新阈值时间条件下的动态能量管理更具有能量效率,延长了传感器网络的生命周期。
针对休眠状态转换和休眠节点唤醒机制,本文分别提出了一种基于能量状态转换策略的混合自动机模型和一种基于消息驱动的休眠节点唤醒算法。该唤醒算法可以有效地避免包传输失败造成的大量能量损失,同时可以大量地减少网络中的冲突。
3.本文讨论了在保持全覆盖和连通性前提下,利用最小工作节点集来获得能量优化的传感器网络的覆盖问题。在高密度的传感器网络中寻找最小工作节点集(即密度控制)是覆盖问题的核心内容。该最小工作节点集能够同时满足网络的全覆盖和连通性要求。当传感器节点的通信距离至少是其感知范围的两倍以上时,凸型目标区域的完全覆盖就意味着工作节点之间的完全连通。
这里,将动态能量管理与传感器网络的覆盖问题相结合,提出了一种基于最优几何密度控制(OGDC)的动态能量管理算法OGDC-DPM。该算法采用后退时间(backoff)方法,可以有效地避免在同一个时间段内多个邻居节点同时成为初始节点的可能。模拟实验表明,该算法具有能量有效性,延长了无线传感器网络的生命周期。
4.本文就无线传感器网络中关于网络生命周期的上限问题展开了讨论和对无线传感器网络的诊断进行了研究。尽管传感器网络可以应用到环境监测中,也可以起到一定的环境保护作用,但是由失效网络或失效节点所产生的大量废电池本身又对环境产生了巨大的威胁。本文首次提出了由传感器节点所产生的环境污染问题,并就此问题提出了初步的解决方法和思路。其中,包括采用高能电池、生物电池、自我能量收集技术和电池无线充电技术等先进和未来的节能技术,以及针对不同应用场景进行利用生命周期分析方法和诊断技术对失效节点进行收集等。
Wireless Sensor Networks is the next generation sensor networks, which integrating sensor technology, embedded computing technology, advanced networking and wireless communication technology and distributed signal information processing techniques. The sensing acquirement technology has been changed from singularity to integration, miniaturization and networking. It will realize the interconnection of physical world, computer world and human society eventually.
Though many specific technical challenges remain and deserve much further study, the primary factor currently limiting progress in sensor networks is not these challenges but is instead the lack of an overall Sensor Network Architecture (SNA). Since limited processing speed, storage capacity, and communication bandwidth of sensor node, the energy consumption is the most important factor to determine the life of a sensor network. This makes energy optimization more complicated in sensor networks because it involved not only reduction of energy consumption but also prolonging the life of the network as much as possible. This can be done by having energy awareness in every aspect of design and operation through the overall SNA. Dynamic power management (DPM) can be used to reduce more energy
consumption. In addition, under the condition of full coverage and connectivity, how to reduce the energy consumption is another important issue.
This paper focuses on the energy problem of wireless sensor networks and has the following researches:
1. The basic idea of Cubic and Cross-Layer (CCL) sensor network architecture proposed in this thesis is combing the layering thought of OSI reference model and cross-layer design of sensor networks.
In CCL, the SNA can be divided into physical layer, sensor service protocol layer (SSP) and application layer. SSP which is similar to the“narrow waist-SP”proposed by Culler, is a common abstraction as a middleware layer. All these services are considered or accessible to be in a cross-layer manner instead of being full encapsulated at one layer, only visible to the one above and below.
2. The DPM policy and algorithm proposed by Sinha have been modified in this paper with considering more factors such as the battery status. In addition, the time threshold which the least time should sensor node be stayed in the sleep state is revised. The sensor network consumed less energy in our simulation than the old one.
A hybrid automata model to represent our sleep state transition policy and message-driven algorithm for awakening the sleep nodes are proposed in this paper. The message-driven algorithm can effectively avoid huge energy consumption caused by to the failure of packet transmission and largely deduce the collision of the networks.
3. This paper addresses the issues of maintaining sensing coverage and connectivity by keeping a minimal number of sensor nodes in the active mode in wireless sensor networks. One important issue that arises in such high-density sensor networks is density control—the function that controls the density of the working sensor set to a certain level. It is desirable to choose a minimal set of working sensors in order to reduce power consumption and prolong network lifetime. If the radio range is at least twice of the sensing range, a complete coverage of a convex area implies connectivity among the working set of nodes.
This paper combines the DPM and coverage problem of sensor networks, proposes an OGDC-DPM algorithm which is a dynamic power management policy based on Optimal Geographical Density Control (OGDC). This algorithm exploits a backoff timer method, which avoids the possibility of multiple neighboring nodes volunteering themselves to be the starting node in a round. The simulation result proved that this algorithm has energy effective and hence prolong the lifetime of the sensor network.
4. This paper discusses the upper bound of sensor network lifetime and the diagnosis of sensor network node. Though WSNs can be used in environment monitoring and protection, the large number of invalidated sensor nodes is a huge hazard to environment. Hence, it is the fist time to propose the environment pollution of sensor nodes in this paper. At last, several solutions to the environment pollution caused by the batteries of sensor nodes are proposes, including high energy battery, biological battery, energy self-collection and wireless recharge techniques and sensor nodes collection. The sensor nodes can be collected by using the analysis of WSNs lifetime and diagnosis technology under different application scenario.
引文
[1]. J. Terry, “Ten emerging technologies that will change the world,” Technology Review, Vo1. 106, No. l, pp.22-49, Feb. 2003, http://www.technologyreview.com/Infotech/13060/.
[2]. G. J. Pottie, W. J. Kaiser, “Wireless Integrated Network Sensors,” Communications of ACM, 43(5), pp. 51-58, May 2000.
[3]. J. Hill, R. Szewczyk, A. Woo, S. Hollar, D.E. Culler, and K.S. J. Pister, “System Architecture Directions for Networked Sensors,” In Architectural Support for Programming Languages and Operating Systems, pp.93–104, Cambridge, Nov. 2000.
[4]. C. Srisathapornphat, C. Jaikeaeo, Chien-Chung Shen, “Sensor Information Networking Architecture,” International Workshops on Parallel Processing, pp. 23-30, 2000.
[5]. L. Akyildiz, W. Su, Y. Sankarasubramaniam, and E. Cayirci, “A Survey on Sensor Networks,” IEEE Communications Magazine, Vol. 40, No. 8, pp. 102-114, 2002.
[6]. A. Sinha, A. Chandrakasan, “Dynamic Power Management in Wireless Sensor Networks,” IEEE Design&Test of computers, Vol.18, Issue 2, pp.62-74, March-April, 2001.
[7]. E. Shih, B. Calhoun, S. Cho, A. P. Chandrakasan, “Energy-Efficient Link Layer for Wireless Microsensor Networks,” Proceedings of Workshop on VLSI 2001 (WVLSI '01),Orlando, Florida, pp. 16-21, April 2001.
[8]. A. Wang, W.B. Heinzelman, A. Sinha, A.P. Chandrakasan “Energy-Scalable Protocols for Battery-Operated Microsensor Networks,” Journal of VLSI Signal Processing, Vol. 29, no. 3, pp. 223-237, November 2001.
[9]. A. Wang and A. Chandrakasan, “Energy Efficient System Partitioning for Distributed Wireless Sensor Networks,” IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP '01), vol.2, pp. 905-908, May 2001.
[10]. G.J. Pottie, “Hierarchical Information Processing in Distributed Sensor Networks,” IEEE International Symposium on Information Theory (ISIT), Cambridge, MA, Aug. 1998.
[11]. D. Estrin, L. Girod, G. Pottie, M. Srivastava, “Instrumenting the World with Wireless Sensor Networks,” IEEE International Conference on Acoustics, Speech, and Signal Processing, pp. 2033-2036, 2001.
[12]. G. Asada, M. Dong, T.S. Lin, F. Newberg, G. Pottie, H.O. Marcy, W.J. Kaiser, “Wireless Integrated Network Sensors: Low Power Systems on a Chip,” In Proceedings of the 24th IEEE European Solid-State Circuits Conference, pp. 9-12, Netherlands, Sept. 1998.
[13]. J.M. Kahn, R.H. Katz and K.S.J. Pister, “Mobile Networking for Smart Dust,” ACM/IEEE Intl. Conf. on Mobile Computing and Networking (MobiCom 99), Seattle, WA, Aug., 1999.
[14]. K.S.J. Pister, J.M. Kahn, B.E. Boser, “Smart Dust: Wireless Networks of Millimeter-Scale Sensor Nodes,” Highlight Article in 1999 Electronics Research Laboratory Research Summary, 1999.
[15]. http://research.cens.ucla.edu
[16]. http://www.janet.cens.ucla.edu/WINS/
[17]. http://bwrc.eecsberkely.edu/
[18]. http://webs.cs.berkely.edu/
[19]. http://www.robotics.usc.edu/~embedded/
[20]. http://www.isi.edu/scadds/
[21]. http://www.ece.gatech.edu/research/labs/bwn/index.html
[22]. http://www.cast.cse.ohio.state.edu/exscal/
[23]. http://www.wings.cs.sunysb.edu
[24]. http://www.eecs.harvard.edu/~mdw/proj/codeblue/
[25]. http://mantis.cs.colorado.edu/index.php/tiki-index.php
[26]. http://www.eng.yale.edu/enalab/
[27]. http://nms.csail.mit.edu/
[28]. http://www.mtl.mit.edu/researchgroups/icsystems/uamps/
[29]. http://lion.cs.uiuc.edu/
[30]. http://projects.cerias.purdue.edu/esp/
[31]. http://www.zurich.ibm.com/sys/communication/sensors.html
[32]. http://www.intel.com/research/exploratory/wireless_sensors.html
[33]. http://www.microsolft.com/nec/
[34]. http://www.xbow.com/Products/Wireless_Sensor_Networks.html/
[35]. http://bwrc.eecs.berkely.edu/Research/Pico_Radio/Default.html/
[36]. http://nesl.ee.ucls.edu/projects/ahlos/
[37]. http://www.intel.com/research/exploratory/motes.htm
[38]. http://www.tinyos.net/
[39]. http://nesl.ee.ucla.edu/projects/sos/
[40]. http://3030.973program.org/ProjectInfo.aspx
[41]. ALERT. http://www.altersystem.org.
[42]. http://www.jpl.nasa.gov/
[43]. E. Shih, S. Cho, N. Ickes, R. Min, A. Sinha, A. Wang, A. Chandrakasan, “Physical Layer Driven Protocol and Algorithm Design for Energy-Efficient Wireless Sensor Networks,” Proceedings of ACM MobiCom’01, pp. 272–286, Rome, Italy, July2001.
[44]. M. Cardei, J. Wu, “Coverage in Wireless Sensor Networks,” Handbook of Sensor Networks,CRC Press, 2004.
[45]. H. Zhang, J.C. Hou, “Maintaining Sensing Coverage and Connectivity in Large Sensor Networks,” Wireless Ad Hoc and Sensor Networks: An International Journal, Vol. 1, pp. 89-123, 2005.
[46]. C. Intanagonwiwat, R. Govindan, D. Estrin, “Directed Diffusion: A Scalable and Robust Communication Paradigm for Sensor Networks,” ACM/IEEE International Conference on Mobile Computing and Networks (MobiCom 2000), Boston, Massachusetts, August 2000.
[47]. R. Perlman, Interconnections: Bridges, Routers, Switches, and Internetworking Protocols, Second Edition, Addison Wesley Professional, 2000.
[48]. G. Hoblos, M. Staroswiecki, A. Aitouche, “Optimal Design of Fault Tolerant Sensor Networks,” IEEE International Conference on Control Applications, pp. 467 – 472, 2000.
[49]. N. Bulusu, D. Estrin, L. Girod, J. Heidemann, “Scalable Coordination for Wireless Sensor Networks: Self-Configuring Localization Systems,” The 6th IEEE International Symposium on Communication Theory and Application (ISCTA 2001), U.K, July 2001.
[50]. H. Zimmermann, OSI Reference Model-The ISO Model of Architecture for Open Systems Interconnection, IEEE Transactions on Communications, 28(4), pp. 425-432, April 1980.
[51]. A. Woo, and D. Culler, “A Transmission Control Scheme for Media Access in Sensor Networks,” Proceedings of ACM MobiCom’01, pp.221-35, Rome, Italy, July 2001.
[52]. A. Koubaa, M. Alves, “A two-tiered architecture for real-time communication in large-scale wireless sensor networks: Research Challenges,” In Proc. of 17th Euromicro Conference on Real-Time Systems (ECRTS'05), WiP Session, Palma de Mallorca (Spain), July 2005.
[53]. J. Blumenthal, M. Handy, F. Golatowski, M. Haase, D. Timmermann, “Wireless Sensor Networks–New Challenges in Software Engineering” Proceedings of 9th IEEE International Conference on Emerging Technologies and Factory Automation(ETFA'03),Vol. 1, pp.:551- 556, Sept. 2003.
[54]. E.Y. Chung, L. Benini,and G.D. Micheli, “Dynamic Power Management Using adaptive Learning Tree,” International Conference on Computer-Aided Design (ICCAD), pp.274 – 279, 7-11 Nov. 1999.
[55]. D. Culler, P. Dutta, C. T. Ee, R. Fonseca, J. Hui, P. Levis, J. Polastre, S. Shenker, I. Stoica, G. Tolle, and J. Zhao, “Towards a Sensor Network Architecture: Lowering the Waistline,” In Proceedings of the Tenth Workshop on Hot Topics in Operating Systems (HotOS X), 2005.
[56]. M.C. Zhang, J.Y. Song, Y. Zhang, “Three-Tiered Sensor Networks Architecture for Traffic Information Monitoring and Processing,” IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2005), pp. 2291- 2296, Aug 2005.
[57]. V. A. Kottapalli et al., “ Two-Tiered Wireless Sensor Network Architecture for Structural Monitoring”, In Proc. of 10th Annual International Symposium on Smart Structures and Materials, San Diego (USA), Mar 2003.
[58]. S.P. Chaudhuri, PHD proposal: An Adaptive Sensor Network Architecture for Multi-scale Communication, 2006.
[59]. T. Bokareva, N. Bulusu, S. Jha. “SASHA: Toward a Self-Healing Hybrid Sensor Network Architecture,” The 2nd IEEE workshop on embedded networked sensors (EmNetS-II), pp. 71- 78, May 2005.
[60]. D.D. Clark. “The Design Philosophy of The DARPA Internet Protocols”, In ACM SIGCOMM, pp.106–114, Stanford, CA, Aug. 1988.
[61]. K. Chakrabarty, S.S. Lyengar, H. Qi, E. Cho, “Grid Coverage for Surveillance and Target Location in Distributed Sensor Networks,” IEEE Trans. on Computers, Vol. 51(12), pp. 1448-1453, 2002.
[62]. P. Levis, N. Patel, D. Culler, S. Shenker, “Trickle: A Self-Regulating Algorithm for Code Maintenance and Propagation in Wireless Sensor Networks,” In First USENIX/ACM Symposium on Network Systems Design and Implementation (NSDI), 2004.
[63]. S.Y. Ni, Y.C. Tseng, Y.S. Chen, and J.P. Sheu, “The Broadcast Storm Problem in A Mobile Ad Hoc Network,” In Proceedings of the fifth annual ACM/IEEE international conference on Mobile computing and networking, pp.151–162, ACM Press, 1999.
[64]. C. Intanagonwiwat, R. Govindan, D. Estrin, J. Heidemann, and F. Silva, “Directed Diffusion for Wireless Sensor Networking,” IEEE/ACM Transactions on Networking, Vol. 11(1) pp.2–16, 2003.
[65]. K. Whitehouse, C. Sharp, E. Brewer, and D. Culler, “Hood: A Neighborhood Abstraction for Sensor Networks,” In Proc. the International Conference on Mobile Systems, Applications, and Services (MOBISYS ‘04), June 2004.
[66]. D. Ganesan, B. Krishnamachari, A. Woo, D. Culler, D. Estrin, and S. Wicker, “An Empirical Study of Epidemic Algorithms in Large Scale Multihop Wireless Networks,” UCLA Computer Science Technical Report UCLA/CSD-TR 02-0013, 2002.
[67]. J. Zhao and R. Govindan, “Understanding Packet Delivery Performance in Dense Wireless Sensor Networks,” In Proceedings of the First International Conference on Embedded Network Sensor Systems, 2003.
[68]. C. E. Perkins, E. M. Royer, and S. Das, “Ad Hoc On Demand Distance Vector (AODV) Routing,” Proceeding of the 2nd IEEE workshop on Mobile Computing Systems and Applications (WMCSA), pp.90-100, 1999.
[69]. J. Newsome and D. Song, “Gem: Graph Embedding for Routing and Data-Centric Storagein Sensor Networks without Geographic Information,” In Proceedings of the first international conference on Embedded networked sensor systems, pp. 76–88, ACM Press, 2003.
[70]. A. Rao, C. Papadimitriou, S. Shenker, and I. Stoica, “Geographic Routing without Location Information,” In Proceedings of the 9th annual international conference on Mobile computing and networking, pp. 96–108, ACM Press, 2003.
[71]. S. Ratnasamy, B. Karp, L. Yin, F. Yu, D. Estrin, R. Govindan, and S. Shenker, “Ght: A Geographic Hash Table for Data-centric Storage,” In Proceedings of the first ACM international workshop on Wireless sensor networks and applications, pp. 78–87, ACM Press, 2002.
[72]. S. Madden, M. J. Franklin, J. M. Hellerstein, and W. Hong, “The Design of An Acquisitional Query Processor for Sensor Networks,” In Proceedings of the 2003 ACM SIGMOD international conference on Management of data, pp. 491–502, ACM Press, 2003.
[73]. K. Sohrabi, J. Gao, V. Ailawadhi, G.J. Pottie, “Protocols for Self-Organization of A Wireless Sensor Network,” IEEE Personal Communications, Vol.7, Issue 5, pp. 16 - 27 ,October, 2000.
[74]. V. Raghunathan, C. Schurgers, Sung Park, M.B. Srivastava, “Energy-Aware Wireless Microsensor Networks,” IEEE Signal Processing Magazine, Vol.19, Issue 2, pp. 40–50, 2002.
[75]. J. Hill, R. Szewczyk, A. Woo, S. Hollar, D.E. Culler, K. Pister, “System Architecture Directions for Networked Sensors,” Architectural Support for programming Languages and Operating Systems, pp.93-104, 2000. Available at http://www.tinyos.net/papers/tos.pdf.
[76]. L. Benini, G.D. Micheli, Dynamic Power Management: Design Techniques and CAD Tools, Kluwer Academic Pub_NY, NY, 1997.
[77]. I.F. Akyildiz, Weilian Su, Y. Sankarasubramaniam, E. Cayirci, “A Survey on Sensor Networks,” IEEE Communications Magazine, Vol.40, Issue 8, pp. 102 – 114, August, 2002.
[78]. L. Benini, A. Bogliolo, G. De Micheli, “A survey of Design Techniques for System-Level Dynamic Power Management”, IEEE Transactions on Very Large Scale Integration Systems (VLSI), Vol. 8, No. 3, pp. 299-316, June 2000.
[79]. A. Sinha, A. Wang, and A.P. Chandrakasan, “Algorithmic Transforms for Efficient Energy Scalable Computation,” Proceedings of International Symposium on Low Power Electronics and Design, pp. 31-36 2000.
[80]. V. Gutnik, A.P. Chandrakasan, “An Embedded Power Supply for Low-Power DSP,” IEEE Trans.VLSI Systems, vol. 5, no. 4, pp. 425-435 Dec. 1997.
[81]. T.A. Pering, T.D. Burd, R.W. Brodersen. “The Simulation and Evaluation of Dynamic Voltage Scaling Algorithms,” In: Proc ISLPED, pp. 76-81, 1998.
[82]. T. Burd, R. Brodersen, “Processor Design for Portable Systems,” Journal of VLSI Signal Processing, Vol. 13(2-3), pp. 203-222, 1996.
[83]. V. Tiwari, S. Malik, A. Wolfe, and M. Lee, “Instruction Level Power Analysis and Optimization of Software,” Journal of VLSI Signal Processing, Vol. 13(2/3), pp.1-18, 1996.
[84]. http://www.transmeta.com
[85]. K. Govil, E. Chan, and H. Wasserman, “Comparing Algorithms for Dynamic Speed-Setting of A Low-Power CPU,” In the 1st ACM International Conference on Mobile Computing and Networking (MOBICOM-95), pp. 13-25, November 1995.
[86]. J. Chang, M. Pedram, “Energy Minimization Using Multiple Supply Voltages,” In International Symposium on Low Power Electronics and Design (ISLPED-96), pp. 157-162, August 1996, also published in IEEE Transaction on VLSI Systems, Vol. 5(4), Dec. 1997.
[87]. T. Ishihara, H. Yasuura, “Voltage Scheduling Problem for Dynamically Variable Voltage Processors,” In International Symposium on Low Power Electronics and Design (ISLPED-98), pp. 197-202, August 1998.
[88]. T. Pering, R. Brodersen, “Energy Efficient Voltage Scheduling for Real Time Operating Systems,” In 4th IEEE Real-Time Technology and Applications Symposium (RTAS-98), Working in Progress Section, 1998.
[89]. S. Muchnick, Advanced Compiler Design and Implementation, Morgan Kaufmann Publishers, Inc., 1997.
[90]. C.H. Hwang, A.C.H. Wu, “A Predictive System Shutdown Method for Energy Saving of Event-Driven Computation,” In IEEE/ACM Int. Conf.Computer-Aided Design, San Jose, CA, pp. 28–32, Nov. 1997.
[91]. R.C. Luo, L.C. Tu, O. Chen, “An Efficient Dynamic Power Management Policy on Sensor Network,” Processing of the 19th international conference on advanced information networking and applications (AINA’05), vol. 2, pp. 341 – 344, 28-30 March, 2005.
[92]. P. Krishnan, P. Long, J. Vitter, “Adaptive Disk Spindown via Optimal Rent-to-buy in Probabilistic Environments,” International Conference on Machine Learning, pp. 322-330, July 1995.
[93]. D. Helmbold, D. Long, E. Sherrod, “Dynamic Disk Spin-down Technique for Mobile Computing,” Conference on Mobile Computing, pp. 130-142, Nov. 1996.
[94]. F. Douglis, P. Krishnan, B. Bershad, “Adaptive Disk Spin-down Policies for Mobile Computers,” USENIX Symposium on Mobile and Location-Independent Computing, pp. 121-137, Apr. 1995.
[95]. S. Ross, Introduction to Probability models, 6th Edition,. Academic Press, 1997.
[96]. M. Puterman, Finite Markov Decision Processes, John Wiley and Sons, 1994.
[97]. L. Benini, A. Bogliolo, G. A. Paleologo, G. De Micheli, “Policy Optimization for Dynamic Power Management,” IEEE Trans. Computer-Aided Design, vol. 18, pp. 813–833, 1999.
[98]. http://www.microsoft.com/hwdev/desinit/onnowapp.HTM
[99]. Hewlett-Packard, Intel, Microsoft, Phoenix, and Toshiba, Advanced Configuration & Power Interface (ACPI): an open industry Specification, Available at: http://www.acpi.info/.
[100]. S.S. Dhillon, K.Chakrabarty, “Sensor Placement for Effective Coverage and Surveillance in Distributed Sensor Networks,” Proceedings IEEE Wireless Communications and Networking Conference (WCNC’03), pp.1609- 1614, USA, 2003.
[101]. A.L.A.P. Zuquim, et al., “Efficient Power Management in Real-time Embedded Systems,” IEEE International Conference on Emerging Technologies and Factory Automation-RTFA’03, vol.1, pp.496 – 505, September, 2003.
[102]. IBM and MontaVista Software, “Dynamic Power Management for Embedded System,” 2002. http://www.research.ibm.com/arl/projects/papers/DPM_V1.1.pdf.
[103]. C.F Chiasserini, R.R. Rao, “Improving Energy Saving in Wireless Systems by Using Dynamic Power Management”, IEEE Transactions on wireless Communications, Vol.2, Issue 5, pp.1090-1100, September, 2003.
[104]. B.Calhoun, A. P. Chandrakasan, "Standby Power Reduction Using Dynamic Voltage Scaling and Canary Flip-Flop Structures," IEEE Journal of Solid-State Circuits, vol. 39, no. 9, September, 2004.
[105]. J.Hui, Z. Ren, B.H. Krogh, “Sentry-Based Power Management in Wireless Sensor Networks,” Second International Workshop on Information Processing in Sensor Networks, pp. 458-472, April, 2003.
[106]. R.M. Passos, C.J.N. Coelho, A.A.F. Loureiro, R.A.F. Mini, “Dynamic Power Management in Wireless Sensor Networks: An Application-Driven Approach,” 2nd Annual Conference on Wireless On-demand Network Systems and Services, pp. 109-118, 2005.
[107]. T.A.Henzinger, “The Theory of Hybrid Automata,” Eleventh Annual IEEE Symposium on Logic in Computer Science (LICS), pp. 278-292, July, 1996
[108]. 任彦,张思东,张宏科,无线传感器网络中覆盖控制理论与算法,Journal of Software, Vol.17, No.3, pp.422-?433, March 2006.
[109]. S. Slijepcevic, M. Potkonjak, “Power Efficient Organization of Wireless Sensor Networks,” IEEE International Conference on Communications (ICC), pp. 472-?476, 2001.
[110]. M. Cardei, D.Z. Du, “Improving Wireless Sensor Network Lifetime through Power Aware Organization,” Wireless Networks, Vol. 11(3), pp.333-3?40, 2005.
[111]. F.Y.S. Lin, P.L. Chiu, “A Near-Optimal Sensor Placement Algorithm to Achieve Complete Coverage/Discrimination in Sensor Networks,” IEEE Communications Letters, Vol. 9(1), pp. 43-4?5, 2005.
[112]. S. Megerian, F. Koushanfar, M. Potkonjak, M.B. Srivastava, “Worst and Best-Case Coverage in Sensor Networks,” IEEE Trans. on Mobile Computing, Vol. 4(1), pp.84-9?2, 2005.
[113]. S. Meguerdichian, F. Koushanfar, G. Qu, M. Potkonjak, “Exposure in Wireless Ad-Hoc Sensor Networks,” Proc. of the ACM Int’l Conf. on Mobile Computing and Networking (MobiCom), pp. 139-1?50, New York, ACM Press, 2001.
[114]. J. Cortes, S. Martinez, T. Karatas, F. Bullo. “Coverage Control for Mobile Sensing Networks,” IEEE Trans. on Robotics and Automation, Vol. 20(2), pp. 243-2?55, 2004.
[115]. D.W. Gage, “Command Control for Many-Robot Systems,” The 19th Annual AUVS Technical Symposium, pp. 22-24, Hunstville, USA, 1992.
[116]. J.O’Rourke, Art Gallery Theorems and Algorithms, Oxford University Press, 1987.
[117]. J.O’Rourke, Computational Geometry Column 15, International Journal of Computational Geometry and Applications, Vol. 2, pp.215-217, 1992.
[118]. M. Marengoni, B.A. Draper, A. Hanson, R. Sitaraman, “A System to Place Observers on a Polyhedral Terrain in Polynomial Time,” Image and Vision Computing, Vol. 18, pp.773-780, 2000.
[119]. R. Williams, The Geometrical Foundation of Natural Structure: A source Book of Design, Dover, 1979.
[120]. A. Heppes, J. Mellissen, Covering a Rectangle with Equal Circles, Period. Math. Hungar. Vol. 34, pp. 65–81, 1997.
[121]. J.B.M. Melissen, P.C. Schuur, “Improved Coverings of a Square with Six and Eight Equal Circles,” Electronics Journal of Combinatorics, 1996.
[122]. K.J. Nurmela, P.R.J. Ostergard, “Covering a Square with Up to 30 Equal Circles,” Research Report A62, Helsinki University of Technology, 2000.
[123]. C.F. Huang, Y.C. Tseng, “The Coverage Problem in A Wireless Sensor Network,” ACM International Workshop on Wireless Sensor Networks and Applications, pp. 115–121, 2003.
[124]. C.F. Huang, Y.C. Tseng, L.C. Lo, “The Coverage Problem in Three-Dimensional Wireless Sensor Networks,” IEEE Proc. of the GLOBECOM. pp. 3182-?3186, Dallas, 2004.
[125]. C.F. Huang, L.C Lo, Y.C. Tseng, W.T. Chen, “Decentralized Energy-Conserving and Coverage-Preserving Protocols for Wireless Sensor Networks,” Proceedings of IEEE International Symposium on Circuits and Systems (ISCAS), Kobe, Japan, 2005.
[126]. Y. Zou, Coverage-Driven Sensor Deployment and Energy-efficient Information Processingin Wireless Sensor Networks, Ph.D. Thesis, Duke University, 2004.
[127]. P. Berman, G. Calinescu, C. Shah, A. Zelikovsky, “Power Efficient Monitoring Management in Sensor Networks,” Proceedings of IEEE Wireless Communications and Networking Conference(WCNC),Vol. 4, pp. 2329- 2334, Atlata, USA, March 2004.
[128]. Z. Abrams, A. Goel, S. Plotkin, “Set k-Cover Algorithms for Energy Efficient Monitoring in Wireless Sensor Networks,” Proc. Information Processing in Sensor Networks Conf. (IPSN '04), pp. 424-432, Apr. 2004.
[129]. F. Ye, G. Zhong, S. Lu, and L. Zhang, “PEAS: A Robust Energy Conserving Protocol for Long-Lived Sensor Networks,” International Conf. on Distributed Computing Systems, 2003.
[130]. D. Tian, N.D. Georganas, “A Node Scheduling Scheme for Energy Conservation in Large Wireless Sensor Networks,” Wireless Communications and Mobile Compuing (WCMC), Vol. 3, pp. 271–290, 2003.
[131]. D. Tian, N. Georganas, “A Coverage-Preserving Node Scheduling Scheme for Large Wireless Sensor Networks,” Proceedings of the 1st International Workshop on Wireless Sensor Networks and Applications (WSNA 2002), pp. 32?41, ACM Press, Atlanta, 2002.
[132]. T. Yan, T. He, J.A. Stankovic, “Differentiated Surveillance for Sensor Networks,” ACM International Conf. on Embedded Networked Sensor Systems (SenSys), pp. 51–62, 2003.
[133]. H. Chen, H. Wu, N.T. zeng, “Grid-Based Approach for Working Node Selection in Wireless Sensor Networks,” Proceedings of the International on Communications, pp. 3673-3678, 2004.
[134]. C. Hsin, M. Liu, “Network Coverage using Low Duty-Cycled Sensors: Random & Coordinated Sleep Algorithms”, In the 3rd International Symposium on Information Processing in Sensor Networks, Berkeley, California, USA, April, 2004.
[135]. J. Lu, T. Suda, “Coverage-Aware Self-Scheduling in Sensor Networks,” Proceedings of IEEE CCW 2003, pp. 117-123, California, 2003.
[136]. G. Xing, C. Lu, R. Pless, J.A. O'sullivan, “Co-grid: An Efficient Coverage Maintenance Protocol for Distributed Sensor Networks,” 3rd International Symposium on Information Processing in Sensor Networks (IPSN '04), April 2004.
[137]. Y. Gao, K. Wu, F. Li, “Analysis on the Redundancy of Wireless Sensor Networks,” Proceedings of the 2nd ACM International Conference on Wireless Sensor Networks and Applications (WSNA 2003,) pp. 108-114, San Diego, ACM Press, 2003.
[138]. H. O. Sanli, H. ?am, “`Energy Efficient Differential Coverage Service Potocols for Wireless Sensor Networks,” Proceedings of 3th IEEE International Conference on Pervasive Computing and Communication. pp. 406-410, Hawaii. March, 2005.
[139]. 刘明,曹建农,郑源, 陈力军,谢立,无线传感器网络多重覆盖问题分析,Journal of Software, Vol.18, No.1, pp.127?136, January 2007.
[140]. H. Zhang, J.C. Hou, “On Deriving the Upper Bound of Alpha-Lifetime for Large Sensor Networks,”' ACM Transactions on Sensor Networks, Vol. 1, No. 2, pp. 272-300, 2005.
[141]. S. Kumar, T.H. Lai, J. Balogh, “On k-Coverage in a Mostly Sleeping Sensor Network,” Proceedings of the ACM MobiCom’04, pp. 144-158, New York, 2004.
[142]. B. Carbunar, A. Grama, J. Vitek, O. Carbunar, “Coverage Preserving Redundancy Elimination in Sensor Networks,” Proceedings of the 1st IEEE Conference on Sensor and Ad Hoc Communications and Networks, pp. 377-386, Santa Clara, 2004.
[143]. X. Wang, G. Xing, Y. Zhang, C. Lu, R. Pless, and C. Gill, “Integrated Coverage and Connectivity Configuration in Wireless Sensor Networks,” In ACM International Conf. on Embedded Networked Sensor Systems (SenSys), pp. 28–39, 2003.
[144]. B. Chen, K. Jamieson, H. Balakrishnan, and R. Morris, “Span: An Energy-Efficient Coordination Algorithm for Topology Maintenance in Ad Hoc Wireless Networks,” ACM/Kluwer Wireless Networks, Vol. 8, No. 5, 2002.
[145]. H. Gupta, S.R. Das, Q. Gu, “Connected Sensor Cover: Self-Organization of Sensor Networks for Efficient Query Execution,” ACM International Symposium on Mobile Ad Hoc Networking and Computing (MobiHOC), pp. 189–200, 2003.
[146]. H. Zhang, J.C. Hou, “Maintaining Sensing Coverage and Connectivity in Large Sensor Networks,” NSF International Workshop on Theoretical and Algorithmic Aspects of Sensor, Ad Hoc Wireless, and Peer-to-Peer Networks, 2004.
[147]. A. Savvides, C. Han, M. Strivastava, “Dynamic Fine-Grained Localization in Ad-Hoc Networks of Sensors,” Proceedings of ACM MOBICOM, pp. 166–179, ACM Press, 2001.
[148]. S. Meguerdichian, F. Koushanfar, M. Potkonjak, M. B. Srivastava, “Coverage Problems in Wireless Ad-Hoc Sensor Networks,” In INFOCOM, pp. 1380–1387, 2001.
[149]. L. Doherty, L. E. Ghaoui, K.S.J. Pister, “Convex Position Estimation in Wireless Sensor Networks,” Proceedings of IEEE Infocom 2001, Anchorage, AK, April 2001.
[150]. www.math.ust.hk/excalibur/v5_n4.pdf, Jensen’s inequality.
[151]. J. Wu, S. Yang, “Coverage Issue in Sensor Networks with Adjustable Ranges,” Proceedings of 33rd International Conference on Parallel Processing Workshops (ICPP 2004 Workshops), pp. 61–68, 2004.
[152]. B. Wang, W. Wang, V. Srinivasan, K.C. Chua, “Information Coverage for Wireless Sensor Networks”, IEEE Communication Letters, 9 (11), pp. 967-969, November, 2005.
[153]. P. Hall, Introduction to the Theory of Coverage Processes, 1988.
[154]. G. Arfken, Lagrange Multipliers, §17.6 in Mathematical Methods for Physicists, 3rd ed.Orlando, FL, Academic Press, pp. 945-950, 1985.
[155]. M.A.M. Vieira, C.N. Coelho, D.C. Jr. da Silva, Jr. J.M. da Mata, “Survey on Wireless Sensor Network Devices,” Proceedings of IEEE Conference on Emerging Technologies and Factory Automation (ETFA '03), Vol. 1, pp. 537- 544, Sept. 2003.
[156]. Y.X. Chen, Q. Zhao, “On the Lifetime of Wireless Sensor Networks,” IEEE Communications Letter, Vol. 9, no. 11, pp.976-978, Nov. 2005.
[157]. G. Potlie, “Wireless Sensor Networks,” Information Theory Workshop, pp.139-140, 1998.
[158]. A.P. Chandrakasan et al., “Design Considerations for Distributed Microsensor Systems,” IEEE 1999 Custom Integrated Circuits Conference (CICC), pp. 279-286, 1999.
[159]. MIT p-AMPS Project, http://www.mtl.mif,.edu/research/icsystems/uamps.html , 1999.
[160]. S. Singh, M. Woo, C.S. Raghavendra, “Power-Aware Routing in Mobile Ad Hoc Networks,” Proceedings of the ACM/IEEE International Conference on Mobile Computing and Networking (MobiCom ’98), Oct. 1998.
[161]. J.H. Chang, L. Tassiulas, “Energy Conserving Routing in Wireless Ad-Hoc Networks,” Proceedings of IEEE INFOCOM 2000, pp. 22-31, 2000.
[162]. W. Heinzelman, A. Chandrakasan, H. Balakrishnan, “Energy-Efficient Routing Protocols for Wireless Microsensor Networks,” Proceedings of 33rd Hawaii International Conference on System Sciences (HICSS ’00), Jan. 2000.
[163]. V. Rodoplu, T.H. Meng, “Minimum Energy Mobile Wireless Networks,” Proceedings of IEEE International Conference on Communications (ICC’98), vol. 3, pp. 1633-1639, 1998.
[164]. M. Bhardwaj, A. Chandrakasan, T. Garnett, “Upper Bounds on the Lifetime of Sensor Networks,” IEEE International Conference on Communications, pp. 785-790, 2001.
[165]. T. Rappaport, Wireless Communications: Principles and Practice, Prentice-Hall, Inc., New Jersey, 1996.
[166]. W. Heinzelman, Application-Specific Protocol Architectures for Wireless Networks, Ph.D. thesis, Massachusetts Institute of Technology, 2000.
[167]. C. Jaikaeo, C. Srisathapronphat, C. Shen, “Diagnosis of sensor networks,” IEEE International Conference on Communications (ICC'01), Helsinki, Finland, June 2001.
[168]. T. lmielinski, S. Goel, “Dataspace - Querying and Monitoring deeply Networked Collections of Physical Objects,” Tech. Rep. DCS-TR-38 1, Rutgeers University, July 1999.
[169]. D.B. Johnson, D.A. Maltz, Dynamic Source Routing in Ad Hoc Wireless Networks, pp. 153-181, Kluwer Academic Publishers, 1999.
[170]. http://www.coa.edu/html/greatduckisland.htm
[171]. R. Amirtharajah, S. Meringer, J.O. MurMiranda, A. Chandrakasan, J. Lang, “A Micropower Programmable DSP Powered using a MEMS-based Vibration-to-Electric EnergyConverter,” 2000 IEEE ISCC,Vol.43, pp. 362-363, February, 2000.
[172]. S. Hollar et al., “Solar Powered 10mg Silicon Robot,” MEMS 2003, Kyoto, Japan, January 19-23, 2003.
[173]. http://www.biotechworld.cn/content.aspx?id=4123
[174]. http://www.ucsb.edu/
[175]. http://www.ed-china.com/ART_8800012844_400011_500009_TS_1C973A3F.HTM
