Wireless Sensor Networks ,Middleware and Programming abstractions


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Seminar Presentation , Wireless and Sensor Networks including a brief discussion on Contiki and TinyOS.

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  • Wireless Sensor Networks :IntroductionApplications of WSNsMain Issues in WSN Middleware and Programming Abstractions for WSNGoals for Middleware and Programming abstractionsOSM : Object State model (FSM)Contiki: Event driven abstractionsTinyOs: Event driven abstractionsConclusionReferences
  • Check on the range and specs of components
  • Local variables allocated on runtime stack, they r exited after an execution as such cn not be used for nested events Global variables lock up the lil available memory
  • Command-line interaction with a network of Contiki nodes● Unix-style pipelines● File system interaction: ls, write, read● Repetition: repeat, randwait● Network commands: netcmd● sense | senseconv● sense | write file | send● repeat 0 20 { randwait 20 { sense | blink | se
  • Rime: low-power, routing● Can run on top of each other
  • n threads = n stacks , n events =1 stack
  • Wireless Sensor Networks ,Middleware and Programming abstractions

    1. 1. Middle ware and ProgrammingParadigms for WSN Budwell Tamuka Masaiti February 23, 2013 JNTUCEH(CSE Department)
    2. 2. Agenda Wireless Sensor Networks :Introduction Applications of WSNs Main Issues in WSN Middleware and Programming Abstractions for WSN Goals for Middleware and Programming abstractions OSM : Object State model (FSM) Contiki: Event driven abstractions TinyOs: Event driven abstractions Conclusion
    3. 3. Wireless Sensor Networks :IntroductionA wireless sensor network (WSN) consists ofspatially distributed autonomous sensors tomonitor physical or environmental conditions,such as temperature, sound, pressure, etc. andto cooperatively pass their data through thenetwork to a main location.
    4. 4. Sensor Node Transceiver 10Kbps-1Mbps 50-125 range Memory (3K-1Mb) Embedded Processor A 8bit 4-8Mhz D Sensor C Transducer Battery
    5. 5. Popular Implementations mica mica2 mica2dot micaz telos telosb rene2 waspmote
    6. 6. WSN Architecture
    7. 7. Environment and Habitat Monitoring http://fiji.eecs.harvard.edu/Volcano
    8. 8. Infrastructure Health Monitoring Monitoring bridge health
    9. 9. HealthCare Monitoring(BAN,PAN)
    10. 10. Smart Metering
    11. 11. WSN Middleware andProgramming Abstractions Middleware provides the software layer interfacing the hardware and the application programs in an OS less system Or the software layer between the OS and the application programs. Programming abstractions refer to the interfaces and data structures provided for a programming model and language
    12. 12. Goals for WSN Middle andProgramming Abstractions Automatic node management Concurrency management Resource management Developer friendly abstractions
    13. 13. Object State ModelOliver Kasten n Kay Romer A programming model and language for programming sensor nodes, based on FSM Uses states and transitions such that the invocation of an event is now a function of both the event and the program state State attributes (infor sharing )
    14. 14. Object State Model(OSM) OSM goes beyond traditional event driven programming and draws inspiration from FSM state charts. OSM is a hybrid FSM implementation which tackles FSM problems such as: Memory Management(Global and local variables) Event hierarchies Manual flow control
    15. 15. OSM Main Features Uses Parallel State Machines Allows hierarchical composition of state(superstates) Explicit program state(not implied) State variables Event queues
    16. 16. ContikiBackground: Contiki – pioneering open source operating system for sensor networks Development started in 2001Got its name from Kon Tiki Across the Atlantic with bare minimum resources
    17. 17. Contiki Key Features Small memory footprint IP networking Hybrid threading model, protothreads Power profiling -measure power consumption at network scale Network shell - for easy command line interaction Designed for portability Dynamic loading
    18. 18. Contiki Communication Stack Two communication stacks uIP TCP/IP Rime low overhead Can run on top of each other
    19. 19. Contik :Event Driven Paradigm The Contiki kernel is event-based Invokes processes whenever something happens Sensor events, processes starting, Process invocations must not block Protothreads provide sequential flow of control in Contiki processes Protothreads extremely lightweight and stackless
    20. 20. Contik :Event Driven Event-driven vs multithreaded Event-driven requires less memory Multithreading requires per-thread stacks Threads require per-thread stack memory Events require one stack Protothreads like events require one stack for as many as there are protothreads running
    21. 21. TinyOs:Event Driven An event driven OS specifically designed for WSN Completely non-blocking Programs are built out of softaware componets Tasks are non –preemptive and run in FIFO order Code is statically linked
    22. 22. TinyOS :Scheduling Two level scheduling: events and tasks Scheduler is simple FIFO A task cannot preempt another task Events preempt tasks (higher priority)
    23. 23.  Provides a specific Service Message Handling, Signal Processing Implemented in a Module(code) Wired up of other components in a Configuration
    24. 24. Comparison Contik n TinyOs
    25. 25. Conclusion Unique challenges and opportunities Expanding areas of applications Contik and TinyOs New research directions
    26. 26. references Geoff Werner-Allen, Konrad Lorincz, and Matt Welsh et al .Monitoring Volcanic Activity at Reventador Volcano, Ecuador with a Wireless Sensor Network Oliver Kansten and Kay Romer. Beyond Event Handlers:Programming Wireless Sensors with Attriunuted State machines A Dunkels,Bjorn Gronvall ,and Thiemo Voigt ,Contiki –a Lightweight and Flexible Operating System for Tiny Networked Sensors”inEmNeTSI,Tampa USA 2005 http://www.wsnmagazine.com/tinyos-tutorial/ http://fiji.eecs.harvard.edu/Volcano https://www.sics.se/search/content/contiki http://www.tinyos.net