ActiveSensorNetworking - - PDF document

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• WrittenbyPhillipLevis

DavidGay DavidCuller PresentedbyStephenNann

• ActiveSensorNetworking

In!networkdynamiccomputations. Scriptingallowsfordataprocessingnearsource. Reducesnetworktrafficandsavesenergy. Uncontrolledenvironmentsresultinbaddata.

Requiresreprogrammingofmotesalreadyin

deployment.

Programsneedsupportforalargeapplication

domain.

Requiresanewarchitectureforin!networkprogramming

models.

• Maté VMLimitations

Conciseprogramsforonlyoneapplication

domain.

Explicitsynchronizationoperationshavetobe

implementedbyprogrammer.

Propagationdonewithexplicitcodeforwarding

andasimplelocalbroadcast.

Complexandlimitedinstructionset. Only3typesofeventhandlers.

• BaseRequirements

Flexibility

Supportwiderangeofapplications.

Concurrency

Automaticimplementationofsafeandeffective

parallelism.

Propagation

Forwardcodereliablyandefficientlywithsupportfor

largerprograms.

• ApplicationSpecificVirtualMachines(ASVM)

HardwareandSoftwareindependence. Programmingwithhighlevellanguages. Reprogrammablewithsmallbytecoded capsules. Protectsmotesfrommaliciousprograms. Customizableinstructionsetandeventtriggering. UsesTricklealgorithmforpropagation. Supportslargeapplicationdomain.

• TemplateComponents

ConcurrencyManager

Handlestheexecutionofcodewithinthreads. Ensuresrace!freeanddeadlock!freeexecution.

Scheduler

ExecutesthreadsinFIFORoundRobinfashionwithfine

granularity.

CapsuleManager

Handlesthestorageandloadingofcapsules. Propagatescapsules.

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• !

ExtensionComponents

Handlers– coderoutinesthatruninresponseto

systemevents.

Operations! functionalcodeunits. Capsules– storethecodesectionsfor

propagation.

• "
• #

$%

Operationsnoteaccesstoasharedresource. Newcapsulesareanalyzedforsharedresources. Handlersareonlyallowedtorunifitcanaccessall

therequiredsharedresources.

TwoPhaseLocking

Start– holdallresources,canreleasewithexecution. Finish– releasesalloftheheldresources.

Rebootswhennewcodearrivestoresetall

variables.

Optionforexplicitsynchronization.

• &

Threadsareexecutedbyfetchingthenextbytecode

fromthecapsulestore.

byteLength allowstheSchedulertokeeptrackofthe

threadsPC.

Allowsmultiplethreadstorunconcurrently.

• $'

Propagatenewcodetoeverynode. Useselectiveexecution– onlysomenodesusethecode. Threenetworktrickles

VersionPackets– 32bitversionnumbersofallinstalled

capsules.

CapsuleStatusPackets– whichfragmentsanodeneeds. CapsuleFragments– piecesofacapsule.

• ()

Handlers

Definedbyusertoreacttocertainsystemevents. Connectedtooperations. Triggerathreadtoexecutecodeinresponsetoa

specifiedevent.

Examples:Timers,Routeforwardingrequest,

ASVMboot.

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• ()

Operations

Definedbyusertoperformapplicationspecific

computations.

Primitives– languagespecific

Ex.jump ASVMsupportsaparticularlanguagebyincludingthe

primitivesitusestocompile.

Functions– languageindependent

Ex.Send() Usertailorstoaspecificapplicationbyimplementing

appropriatefunctionsandhandlers.

• *

DescriptionFilewith

scriptsdefined.

Specify3things:

Language Functions Handlers

Thetoolchain

generatesTOSsource codeandmaps

• pcodes.
• (+,)-%

Languages

• TinyScript
• BASIClikedynamictyping.
• Nodynamicallocation.
• Motlle
• Clikesyntax.
• Supportsvectors,lists,strings,andfirst!classfunctions.
• Allhandlerstransmittedinonecapsule.Noincrementalchanges to

runningprograms.

• (+,)-%

Applications

RegionsVM

VehicletrackingwritteninTinyScript.

QueryVM

Periodicdatacollectionwithinnetworkaggregation. WritteninTinySQL. AggregationlibrariescompiledtoMotlle. TinySQL supportsnewaggregationquerieswrittenin

Motlle.

• !

(+,$%

• 24sharedresourcesanda128bytehandler.
• LockingandUnlocking
• Fewmicroseconds.
• Lookingforasharedresource
• <1ms
• Managercanprovideshareddatasafetywithlittleoverheadcost.
• "

(+,.'

• Tricklealgorithm.
• 100bytehandlerinjected.
• Averagereprogram≈ 40s.
• Worstcase≈ 85s.
• ASVMonlyhadtosend71Bhandlerratherthan19kBimage.

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$/

Difficulttopredictwhatdatawilllooklikefromeach

mote.

Programminginhighlevellanguageincreases

executiontimeduetointerpretation.

Initialcodeimageismuchlarger. Increasedoverheadduetoraceanddeadlock

checking.

Propagationtechniqueisslowandrequires3

transmissions.

• 0 $1'

ASVMhas6%moreoverhead. ASVMhas20%betterenergyefficiencywith

propagation.

ASVMprovidescustomizableinstructionsandevent

handling.

ASVMprovidesautomaticraceanddeadlock

checking.

ASVMprovidesamoreenergyefficientpropagation

algorithmwithsupportforlargerprograms.

ASVMallowsforgreaterlanguageandapplication

flexibility.

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