NSF Project: Monitoring Dynamic Spatial Fields Using Responsive Geosensor Networks

Updated June 2009

PI: Mike Worboys, Co-PI: Silvia Nittel (Geo-Sensor Networks Lab)

Graduate students: Jixiang Jiang (PhD student), Cheng Zhong (MS student), Danqing Xiao (MS student)

This material is based upon work supported by the National Science Foundation under Grant No. 0534429.
Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation (NSF).

The project abstract may be found here

Brief project description  Research tasks and results  Collaborations  Broad impacts   Resources

Brief project description

Environmental phenomena, such as changes in global levels of atmospheric carbon dioxide, can be modeled as variations of measurements over regions of space and time, called dynamic spatial fields. The goal of this project is to provide efficient ways for sensor networks to monitor such fields, and to report significant changes in them. The focus is on qualitative changes, such as splitting or emergence of holes in a region of high activity. The approach is to develop qualitative and topological methods to deal with changes. We use a combinatorial map model of the sensor network, which is rich enough so that for each sensor, its position, and the distances and bearings of neighboring sensors are easily computed. The sensors are responsive to changes in the spatial field, so that sensors are activated in the vicinity of 'interesting' developments in the field, while sensors are deactivated in quiescent locations. All computation and message passing is local, with no centralized control. Optimization is addressed through use of techniques in qualitative representation and reasoning, and efficient update through a dynamic and responsive underlying spatial framework.

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Research tasks and results

Research Task 1: Dynamic spatial fields (Dr. Worboys)  
RT1 is concerned with characterizations of the qualitative aspects of the dynamic field and their relationship to the combinatorial map structure.

  1. The taxonomy of spatial changes proposed in year 2 is refined and extended in year 3. In this ongoing work, we have focused on the development of an ontology of spatial changes in OWL (web ontology language) using Protégé 3. This ontology contains over 200 classes, including the class' terminological definition and the class' formalized restrictions. (Danqing Xiao,  Silvia Nittel, Mike Worboys, Year 3)
    [Classes of topological changes] [Classes of metric changes] [owl file download]
  2. We have worked on the formal modeling of continuous spatial phenomena for geosensor networks. We thoroughly reviewed the former studies in the wireless sensor network field on boundary detection. Then we looked at how to track boundary deformation spontaneously over time. (Danqing Xiao, Silvia Nittel, Year 3)
  3. We have proposed the local tree model for representing spatial changes, based on which a complete set of  types of topological changes is specified.  The local tree model provides a foundation for topological change detection using sensor networks. (Jixiang Jiang, Mike Worboys, Year 3)  [Technical report]
    Publication:  J. Jiang, and M. Worboys,  "Preliminaries for topological change detection in sensor networks."In Proc. of 3rd International conferences on Geosensor networks, Oxford, England, 2009
  4. We have set up a comprehensive taxonomy of all spatial changes. An ontology of qualitative continuant in dynamic spatial fields is under construction and implementation in Protégé. (Danqing Xiao, Mike Worboys, Year 2)
    [The taxonomy]
  5. A two-layer framework is proposed for analyzing spatial and temporal entities for sensor networks. In the first layer, basic objects and events directly from collected sensor data are conceptualized. In the second layer, the data level entities are projected onto the information level to be expanded to global-level and semantic-rich entities.  (Danqing Xiao, Year 2)
     
  6. We have provided an analysis and classification of events associated with  the changes in topological structure of spatial areal objects as they evolve through time. The classification results provide a foundation for converting the qualitative spatial-temporal sensor readings into quantitative description. (Jixiang Jiang, Mike Worboys, Years 1,2)  
    Publication: J. Jiang, and M.     Worboys,  "Event-based topology for dynamic planar areal objects."International Journal of Geographic Information Science, 23(1):33-60, 2009.

Research Task 2: Combinatorial maps (Dr. Worboys)  
Research Task 3: Using combinatorial maps as communication network topology (Dr. Nittel) 
RT2 concerns the combinatorial map as the underlying topological structure of the sensor network, and its relationship to the sensor network, and responsiveness the dynamic field. RT3 focuses on algorithms to use combinatorial maps as communication network topology.

  1. Using Delaunay triangulation to set up the communication network topology, a new topological change detection approaches is proposed. This approach collects the information required by the local tree model, and determines the type of change by the model. Communication cost is reduced using a boundary group based framework. (Jixiang Jiang, Mike Worboys, Years 2,3)  
    Publication: J. Jiang, and M. Worboys, "Detecting basic topological changes in sensor networks by local aggregation."In Proc. of ACMGIS 2008, Orange County, CA, 2008. [presentation slides]
  2. The approach proposed in stage 1 is improved. A more flexible boundary group framework is proposed that enables reusing the time-invariant data during the monitoring. Communication cost is further reduced based on the new framework. . (Jixiang Jiang, Mike Worboys, Silvia Nittel, Year 3)  [Technical Report]
    Publication: J. Jiang, M.F. Worboys, and S. Nittel, "Qualitative change detection using sensor networks based on connectivity information", Geoinformatica, (under review)
  1. Based on the combinatorial map model, a data structure is designed that enables each sensor to store its neighbor information efficiently. This data structure helps to save network energy. Simulation experiments agreed very well with the design.  (Cheng Zhong, Mike Worboys, Years 1,2)
    Publication: C. Zhong, and M. Worboys,"Continuous contour mapping in sensor networks."In Proc. Of the 5th IEEE Consumer Communications and Networking Conference (CCNC), Las Vegas, NV, 2008. [presentation slides]
     
  2. As an extension of the work in 2, an energy-efficient technique, isovector aggregation, is proposed. This technique reports and reconstructs the contour maps at the base station, which provides an efficient way to visualize and monitor the dynamic fields. (Cheng Zhong, Mike Worboys Years 1,2)
    Publication: C. Zhong, and M. Worboys, "Generating contours in a sensor network using isovector aggregation."In Proc. Of the 5th IEEE Upstate NY Workshop on Communications, Sensors and Networking, 2007. [presentation slides] [technical report]
  3. We have modeled a specific combinatorial map as the basic topological structure for the triangulation over the nodes of a sensor network. The model provides a framework for the detection of global high-level events based on local low-level “snapshot” spatiotemporal data. (Mike Worboys,  Matt Duckham, Year 1)
    Publication: M.  Worboys,  and M. Duckham,"Monitoring qualitative spatial change for geosensor networks."International Journal of Geographic Information Science, 20(10), 1087-1108, 2006.

Research Task 4: Monitoring the field based on qualitative information (Dr. Nittel)
RT4 relates to real-world experiments with qualitative properties of continuous phenomena.

  1. A simulation environment is setup based on Prowler, a Matlab-based network simulator. Both topological change detection approaches proposed in RT2-3 are implemented and tested. Sample videos that show the detection procedure of both approaches can be downloaded at our project website.(Jixiang Jiang, Mike Worboys, Silvia Nittel, Year 3)
         [Sample Video 1 - local aggregation approach] [Sample Video 1 - local boundary reporting approach]
    -- In the video, red nodes represent nodes participated in the reporting, star nodes represent the group heads, and edges between the nodes show the routing trees constructed in the groups

  2. We have defined topological change and present in-network algorithms to detect such changes. An adaptive sensor network management strategy is applied, and energy efficiency is achieved by dynamic sensor activation and deactivation.   ( Christopher Farah, Cheng Zhong, Mike Worboys, Silvia Nittel, Year 2)
    Publication: C. Farah, C. Zhong, M. Worboys, and S. Nittel, "Detecting topological change using a wireless sensor network." Proceedings of Geographic Information Science (GIScience 2008), Springer LNCS 5266, 55-69
  3. Dr. Nittel has published a paper with Dr. Young J. Young with regard to processing real-world sensor data collected over a campus area in Korea, and to represent the sensor data as layers for further processing and spatial queries.  (Year 2)
    Publication:     Y. J. Jung, and S. Nittel, 2008, "Geosensor Data abstraction for environmental monitoring application."In Proceedings of Geographic Information Science (GIScience 2008), Springer LNCS 5266, 168-180.
  4. Dr. Nittel participated in the spring 2008 IGERT testbed class, which constructed a wireless sensor network to measure the light field around tomato plants in a commercial greenhouse in Madison, ME. She assisted the students in their field trip to set-up the network, and test the sensor data collection.  (Year 2)

Other publications

  1. J. Jiang, "Specifying and detecting topological changes to an areal object.", Ph.D. dissertation, University of Maine, 2009.
  2. C. Zhong, "Generating  contour maps for dynamic fields monitored by sensor networks. ", Master thesis, University of Maine, 2008.
  3. J. Stell and M. Worboys, "A theory of change for attributed spatial entities."In Proceedings of Geographic Information Science (GIScience 2008), Springer LNCS 5266, 308-319.
  4. S. Nittel, A. Labrinidis, and A. Stefanidis, "Advances in geosensor networks."Springer LNCS 4540, 2008  (Book).
  5. A. Klippel, M. Worboys, and M. Duckham, "Identifying factors of geographic event conceptualisation."International Journal of Geographic Information Science, 22(2), 183-204.
  6. M. Duckham,  M. Worboys, and A. Galton, "Efficient generation of simple polygons for characterizing the shape of a set of points in the plane."Pattern Recognition, 41(10), 3224-3236, 2008.
  7. A. Klippel, M. Worboys, and M. Duckham, "Conceptual neighbourhood blindness – on the cognitive adequacy of gradual topological changes."Conference on Spatial Cognition, Workshop on Talking about and perceiving moving objects: exploring the bridge between natural language, perception and formal ontologies of space. Bremen, Germany, 2006.
  8. M. Worboys, and M. Duckham,  "Formalizing mobility in dynamic location-aware sensor networks."(short paper). International Workshop on Mobile Location-Aware Sensor Networks, Nara, Japan, IEEE Publications, 2006.
  9. J. Jiang, and M. Worboys,  "Specifying events by changes in topological properties (Extended Abstract)."  presented at Geographic Information Science-Fourth International Conference, GIScience 2006, Germany, 2006.
  10. C. Farah, and  M. Worboys, "Specifying qualitative analysis of a scalar field using a  wireless sensor network  (Extended Abstract)"  presented at Geographic Information Science-Fourth International Conference, GIScience 2006, Germany, 2006.

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Collaborations

(Jan. 2009 and July 2008) Dr. John Stell from University of Leeds, UK visited our department twice. During the visits, Dr. Stell worked with PI Dr. Worboys on the development of theories on qualitative spatial changes, as well as the analysis of granularity issues related to these changes.

(Nov. 2008) Dr. Matt Duckham from University of Melbourne, Australia, visited our department. During his visit, Dr. Duckham presented and discussed with the members of sensor network group in the area of decentralized spatial-temporal computing, and cooperated with us to explore the new area of sensor network-based 3D environmental phenomena monitoring.

(Aug./20/2008 - Oct./20/ 2008)  Dr. Nittel visited Dr. Niki Trigoni at the Computational Lab, University of Oxford, from  for collaboration during her sabbatical. The focus of the collaboration is the usage of mobile data collections sinks for fixed sensor networks.

(Jan. 2007)  Dr. Worboys visited the the Department of Geomatics, University of Melbourne, Australia to work with collaborator Dr. Matt Duckham.

(Jan./01/2008 - Mar./24/2008)  Dr. Worboys visited the School of Computing, University of Leeds, UK to work with collaborators Dr. John Stell and Dr. Tony Cohn.

(Sept. 2007 - May 2008) Periodic online meetings were hold between this project group at University of Maine and the Distributed Spatial Computing group at  University of Melbourne, Australia.
Presentations from University of Melbourne:
Sept./13/2007, Muhammad Jafar Sadeq, Distributed detection of spatiotemporal change of regions using boundary state
Oct./22/2007, Matt Duckham, Distributed environmental simulation and feedback in robust geosensor networks
Dec./03/2007, Patrick Laube, FLAGS —flocking amongst geo-sensors
Apr./23/2008, Muhammad Jafar Sadeq, Effect of neighborhood on in-network processing

Presentations from University of Maine:
Sept./13/2007, Cheng Zhong, Detect region changes locally in sensor networks
Oct./22/2007, Christopher Farah, Making use of routing protocols to detect events in wireless sensor networks (WSNs)
Dec./03/2007, Jixiang Jiang, Study on classifications of topological changes
Apr./09/2008, Mike Worboys, Some more thoughts on change
May/26/2008, Jixiang Jiang, Detecting topological changes in sensor networks by local aggregation

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Broad impacts

IGERT 
The project is closely integrated with a new NSF IGERT Program on Sensor Science, Engineering, and Informatics (SSEI). Both PIs Dr. Worboys and Dr. Nittel are Executive Committees of the program, and both are the panelists of the informatics panel, SSEI IGERT summer institute workshop in 2008 and 2009, respectively.

Conferences and workshops organized
Dr. Nittel serves as the Program Committee and General Co-Chair of the 1st International Workshop on Privacy-Aware Location-Based Mobile Services (PALMS'07), in conjunction with Mobile Data Management,  Mannheim, Germany, May 2007. She also serves as a Steering Committee of the 3rd  Conference on Geosensor Networks (GSN3.0), Oxford, UK, July 2009.

Academic services
Dr. Worboys is a Program Committee Member for the following conferences and workshops: 
ISGIS 2010, SSTD 2009, GSN 2009, ACM-GIS 2009, AGILE 2009, MEDES 2009, GeoS 2009,  COSIT 2009, SMPS 2008, AR2008, ACM-GIS 2008, GIScience 2008, GIDays 2008, GeoS 2007, DG/SUM 2007, ITSC 2007, AGILE 2007, COSIT 2007, ACM-GIS 2007, GIDays 2007
Dr. Worboys serves as the editor-in-chief for the Journal of Spatial Information Science since 2009. He is also serves on the other editorial boards, including Oxford University Press Spatial Information Science Series, International Journal of Geographical Information Science, Transactions in GIS, Geoinformatica, Computers in Environmental and Urban Systems, Cartography and Geographic Information Science, USISA, and Geography Compass.

Dr. Nittel is a Program Committee Member for the following conferences and workshops: 
SSDBM 2010, DMSN 2009, ACM-GIS 2009, VLDB 2009, DKSS 2009, MDM 2009, ACM-GIS 2008, SSDBM 2008, ICDE 2008, DMSN 2008, MobiDE 2008, DMSN 2007, VLDB 2007, SSDBM 2007, ICDE 2007, ESNs 2007

Awards
 Dr. Worboys receives University Consortium for Geographic Science (UCGIS) Research Award in 2008, and the Distinguished Scientist Award from Association of Computing Machinery in 2006. He also holds an Honorary Professorial Fellow in the Department of Geomatics, University of Melbourne, Australia since 2005.

Presentations, keynotes and invited lectures at multidisciplinary conferences

  1. Danqing Xiao, "Modeling spatial changes in geosensor networks", poster presentation at Graduate Expo, University of Maine, April 2009
  2. S. Nittel, "Geosensor Networks: New Challenges in Environmental Monitoring using Wireless Sensor Networks Sensing in a Changing World", keynote, November 20, 2008, Centre for Geo-Information, Wageningen, Netherlands
  3. Jixiang Jiang, "Detecting basic topological changes in sensor networks by local aggregation", ACM-GIS 2008, Orange County, CA, Nov. 2008. [presentation slides]
  4. S. Nittel, "Geosensor Networks: State of the Art", invited talk, Computing Lab, Oxford University, Oxford, UK, October 3 2008.
  5.   S. Nittel, "Geosensor Networks: State of the Art", invited talk, Computing Lab, Cambridge University, Cambridge, UK, October 1 2008.
  6. S. Nittel, "Geosensor Networks: State of the Art", invited talk, Chungji University, Cheongjy, Korea, June 2008. 
  7. Mike Worboys, Invited keynote address at the Workshop on Temporal GIS, the Past 20 Years and the Next 20 Years,  Park City, Utah, 23 Sept. 2008
  8. Mike Worboys, "Models of geospatial change. "Invited seminar given to the Department of Computer Science, University of Minnesota, Apr. 28, 2008.
  9. Mike Worboys, "Geography in motion. "Invited lecture to University College London, England, Centre for Advanced Spatial Analysis, CASA Seminar, Jan. 23, 2008.
  10.   Mike Worboys, "Geography in motion. "Invited lecture to University of Edinburgh, Scotland, EScience Centre Guest Lecture, Mar. 11, 2008.
  11.  Mike Worboys, "Geospatial change. "Invited presentation, delivered to the  Third Environment Ontology Workshop at The University of Manchester, England, Mar. 13-15, 2008.
  12. Mike Worboys, Invited lectures on spatio-temporal formation systems, delivered remotely to the IFGI Spring School, University of Munster, Germany, Mar. 2008.
  13. Cheng Zhong. "Continuous contour mapping in sensor networks. " CCNC 2008, Las Vegas, NV, 2008. [presentation slides]
  14. Silvia Nittel. "Geosensor networks: state of the art and looking ahead."Keynote, Muenster GI-Days, 2007  Muenster, Germany, Sept. 11 2007.
  15.  Silvia Nittel. "Geosensor networks: a vision perspective."Invited Talk, Invited Workshop on Ubiquitous Spatial Computing, Portland, ME, Jan. 15 2007. 
  16.   Cheng Zhong "Generating contours in a sensor network using isovector aggregation. "The 5th IEEE Upstate NY Workshop on Communications, Sensors and Networking, 2007. [presentation slides]
  17.   Danqing Xiao, "Study of cultural impacts on location judgments in eastern China. "COSIT 2007. [presentation slides]

Related research awards (accepted/submitted)

  1. M. Worboys, Government of South Korea, Indoor Spatial Awareness, $270,000, 2008-2011.
  2. K. Beard, R. Lad, R. Smith, J. Vetelino and M. Worboys, National Science Foundation, Research Grant DGE-0504494, IGERT, Sensor Science, Engineering, and Informatics, $3,339,065, 2005-2010.
  3. M. Worboys, Ordnance Survey of Great Britain, for research with Oracle Inc. to develop a spatiotemporal data model, $138,000, 2005-2007
  4. M. Worboys, N.Guidice, National Science Foundation, Research Grant, Proposal No: 0916219, III:RI:Small: Information integration and human interaction for indoor and outdoor spaces, $478,715, submitted Dec. 2008.
  5. M. Worboys, J. Saros, J. Peckenham, National Science Foundation, Research Grant, Proposal No:0916255, III:Small: Decentralized spatiotemporal computing for monitoring environmental phenomena, $494,968, submitted Dec. 2008.

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Resources

Papers in the area of homology in sensor networks

  1. V Silva, R Ghrist, "Homological sensor networks. "In Notices of the American Mathematical Society,  54(1), pp. 10 – 17, 2007.
  2. R. Ghrist, and A. Muhammad. "Coverage and hole-detection in sensor networks via homology."In Proc. 4th Internat. Sympos. Information Processing in Sensor Networks, pp. 254–260, 2005.
  3. C. A. Delfinado, and H Edelsbrunner, "An incremental algorithm for Betti numbers of simplicial complexes. "In Proceedings of the ninth annual symposium on Computational geometry, pp. 232-239, 1993.
  4. Muhammad and A. Jadbabaie, "Decentralized computation of homology groups in networks by gossip. "In Proceedings of American Control Conference, pp. 3438-3443, 2007.

Papers in the area of boundary (contour) detecting and reporting

  1. J. Lian, L. Chen,  K. Naik, Y. Liu, and G.B. Agnew, "Gradient boundary detection for time series snapshot construction in sensor networks. "In IEEE Transactions on Parallel and Distributed Systems, 18(10), pp. 1462–1475, 2007.
  2. X. Zhu, R. Sarkar, J. Gao, and J.S.B. Mitchell, "Light-weight contour tracking in wireless sensor networks."In INFOCOM, 2008, pp. 1175–1183.
  3. R.  Sarkar, X. Zhu, J. Gao, L.J. Guibas, and J.S.B. Mitchell, "Iso-contour queries and gradient descent with guaranteed delivery in sensor networks."In INFOCOM, 2008, pp. 960–967.
  4. S. Gandhi, J.  Hershberger, and S.  Suri, "Approximate isocontours and spatial summaries for sensor networks."In IPSN, 2007, pp. 400–409.
  5. A. Silberstein, R. Braynard, and J. Yang, "Constraint chaining: on energy-efficient continuous monitoring in sensor networks."In Proc. of the 2006 ACM SIGMOD Intl. Conf. on Management of Data, 2006, pp. 157–168.
  6. I. Solis, and K. Obraczka, "Efficient continuous mapping in sensor networks using isolines."In Proc. of the 2005 MobiQuitous, 2005, pp. 325–332.
  7. J. M. Hellerstein, W. Hong, S. Madden, and K. Stanek, "Beyond average: Toward sophisticated sensing with queries."In IPSN, 2003, pp. 63–79.
  8. X. Meng, L. Li, T. Nandagopal, and S. Lu, "Event contour: An efficient and robust mechanism for tasks in sensor networks."Technical Report, UCLA, 2004.
  9. K. Chintalapudi, and R. Govindan, "Localized edge detection in sensor fields."In Ad Hoc Networks, vol. 1, no. 2-3, pp. 273–291, 2003.
  10. M. Ding, D. Chen, K. Xing, and X. Cheng, "Localized fault-tolerant event boundary detection in sensor networks ."In INFOCOM, 2005, pp. 902–913.
  11. B. Krishnamachari, and S. Iyengar, "Distributed bayesian algorithms for fault-tolerant event region detection in wireless sensor networks."In IEEE Transactions on Computers, Vol. 53, No. 3, pp. 241–250, March 2004.
  12. J. Zhao, R. Govindan, and D. Estrin: "Residual energy scans for monitoring wireless sensor networks."In: Proceedings of the IEEE Wilress Communications and Networking Conference (WCNC 02). (2002) 17–21
  13. R. Nowak, and U. Mitra, "Boundary estimation in sensor networks: theory and methods."In Proceedings of the First International Workshop on Information Processing in Sensor Networks, April 2003.

Papers in the area of dynamic network configuration

  1. M.K. Watfa, and S. Commuri, "An energy efficient approach to dynamic coverage in wireless sensor networks."In Journal of Networks, Vol. 1, No. 4, Aug. 2006.
  2. M. Duckham, S. Nittel, and M.F. Worboys, "Monitoring dynamic spatial fields using responsive geosensor networks."In ACMGIS 2005: 51–60
  3. K. Kar, A. Krishnamurthy, and N. Jaggi, "Dynamic node activation in networks of rechargeable sensors."In INFOCOM 2005. 24th Annual Joint Conference of the IEEE Computer and Communications Societies. Proceedings IEEE Volume 3, 1997–2007.
  4. W. Zhang, and G. Cao, "DCTC: Dynamic convoy tree-based collaboration for mobile target tracking." In IEEE Transactions on Wireless Communications, Vol. 3, No. 5, pp. 1689–1701, 2004.
  5. J. Liu, P. Cheung,  L. Guibas, and F. Zhao,  "A dual-space approach to tracking and sensor management in wireless sensor networks."In WSNA,  pp. 131–139, 2002.
  6. Y. Xu, J. Heidemann, and D. Estrin, "Geography-informed energy conservation for ad-hoc routing."In Proceedings of the Seventh Annual ACM/IEEE International Conference on Mobile Computing and Networking 2001, pp. 70–84.

Papers in the area of topological boundary detection

  1. Q. Fang, J. Gao, and L. Guibas. "Locating and bypassing routing holes in sensor networks."In Proc. Mobile Networks and Applications, vol. 11, pp. 187–200, 2006.
  2. A. Kröller, S.P. Fekete, D. Pfisterer, and S. Fischer. "Deterministic boundary recognition and topology extraction for large sensor networks."In Proc. 17th ACM-SIAM Sympos. Discrete Algorithms, pp. 1000–1009, 2006.
  3. Y. Wang, J. Gao, and J.S.B. Mitchell, "Boundary recognition in sensor networks by topological methods."The 12th Annual International Conference on Mobile Computing and Networking (MobiCom'06), 122–133, September, 2006.
  4. S.P. Fekete, M. Kaufmann, A. Kröller, and N. Lehmann. "A new approach for boundary recognition in geometric sensor networks."In Proc. 17th Canadian Conference on Computational Geometry, pp. 82–85, 2005.
  5. S. Funke. "Topological hole detection in wireless sensor networks and its applications."In Proc. Joint Workshop on Foundations of Mobile Computing, pp. 44–53, 2005.
  6. S.P. Fekete, A. Kröller, D. Pfisterer, S. Fischer, and C. Buschmann. "Neighborhood-based topology recognition in sensor networks."In Proc. of ALGOSENSORS, Springer LNCS vol. 3121, pp. 123–136, 2004.
  7. B. Deb, S. Bhatnagar, and B. Nath. "STREAM: Sensor topology retrieval at multiple resolutions."In Telecommunication Systems 26(2-4), pp. 285–320, 2004.

Other useful paper resources

A Wireless Sensor Networks Bibliography , Distributed sensor network reading list

Simulation tools

TinyOS, Network Simulator 2, Prowler

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