Slide 1Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21SAFE (Sinks Accessing data From Environments)Authors: Sooyeon Kim, Sang H. Sony, John A. Stankovicy, Shuoqi Liy, Yanghee ChoiPresented by: Chih-Ping ChouSAFEA Data Dissemination Protocol for Periodic Updates in Sensor NetworksAttempts to save energy through data dissemination path sharing among multiple data sinks.Why SAFE?It's a heavy load to construct grid networks per data source.It's infeasible to let every potential data source keep flooding their measurement before any explicit user requests.Complicated setup phase of grid constructionLong-term comparison between multiple data delivery pathsProtocol design criteriaImmediate deploymentAdaptabilityFast response to data requestsEnergy efficiencyData dissemination in a two-tiered networkStationary sensor nodesMobile data usersEnvironmental modelATMEL 90LS8535 processor8 KB flash program memory512 byte SRAM data memoryRF Monolithic 916.50 MHz transceiverPhoto/Temperature sensorsProposed ProtocolData management tableQuery transferrecvQuery(q)1 if isRecentlyDealtWith (q)2 then return3 saveQueryAsRecentOne (q)4 if isSource (q)5 then sendPathSetup (sender(q))6 else if isJunction (q)7 then sendJunctionInfo (sender(q))8 else if isApproachingToSource (q)9 then forwardQueryToNextHop (q)Dissemination path setuprecvPathSetup (p)1 if destination (p) 6= myAddr2 then if noEntryInDataManTable (p)3 then e createEntry (p)4 waitForAckFromSink (e)5 else /* if the PathSetup p is destined for this node */6 then e findEntry (p)7 if currState (e) = QUERY SENT8 then sendAck (hopSender (p))9 changeMyState (e, SUBSCRIBE SENT)10 else if currState (e) = FEEDBACK RCVD11 then if bestFeedbackCost (e) > cost (p)12 then saveAsBestFeedback (p)How SAFE establishes data delivery pathsHow SAFE establishes data delivery pathsHow SAFE establishes data delivery pathsHow SAFE establishes data delivery pathsConclusionEnergy efficiencyScalability Both of which are crucial for large-scale battery-powered sensor networksFuture workData aggregation that accumulates multiple data provision into a single hop-by-hop
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