Web Update Applications Outline Distributed Microsensing Reason 1 up-close Distributed Microsensing Distributed Microsensing Reason 2 Reason 3

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1 Web Update pplications Chenyang Lu Sensor boards available for projects Sensor boards from Crossbow Slides posted on schedule page Schedule and reading list will be updated on Monday CSE 521S 2 Outline Case for wireless sensor networks Distributed microsensing Multi-hop ad hoc network Example applications Structural monitoring Emergency care Reason 1 Strength of signals decay with distance Electromagnetic wave: intensity 1/distance 2 in free space. CSE 521S 3 CSE 521S 4 Reason 2 Signals can disperse and reflect Light, radio, sound Reason 3 Signals can be obstructed cannot be measured from distance CSE 521S 5 CSE 521S 6 1

2 Reason 4 Coverage large areas with one device is difficult Difficult to separate and track multiple targets at the same time Multi-phase radars, cameras Limited angle of view Cameras Hence dense, distributed sensing is good Reason 5 The reliability of parameter estimation depends on both SNR and the number of independent observations Hence dense distributed sensing is good CSE 521S 7 CSE 521S 8 Reasons 1. Signal decay 2. Signal dispersion 3. Signal obstruction Sense up close 4. Cover multi-objects and large areas 5. ccuracy improve with the number of independent measurements Dense, distributed sensing More Reasons Non-intrusive : animals, plants Low cost CSE 521S 9 CSE 521S 10 Multi-hop d Hoc Network Reason 1 Power radio signal strength 1/distance B Transmission power = (2) 4 = r C r----- B Transmission power = + = 2 Multi-hop can be more power efficient Multi-hop d Hoc Network Reason 2 Space multiplexing C X B D Multiple-hop better throughput C B D CSE 521S 11 CSE 521S 12 2

3 Multi-hop d Hoc Network More Reasons Flexibility Circumvent obstruction Robustness Fix broken paths Scalability Wireless Sensor Networks Disadvantages Complexity of distributed systems Privacy/security Environmental concerns Harsh and uncontrolled environment Self-calibration, self-monitoring, self-healing Lack computation power Heterogeneous platform CSE 521S 13 CSE 521S 14 Outline Case for sensor net Distributed microsensing Multi-hop ad hoc network Example applications Structural monitoring Emergency care Habitat Monitoring Goal: Monitor usage patterns of burrows burrow and environmental changes differences between nesting areas and others CSE 521S 15 CSE 521S 16 Tiered rchitecture Requirements 9-month season low power low duty cycle Handle hash environment Verification network Health monitoring Non-real-time, low data rate 5-10 min: entry/leave 2-4 hr: environmental differential No in-network processing: data streaming CSE 521S 17 CSE 521S 18 3

4 Surveillance Wireless Integrated Networked Sensors (WINS) Reliability Detection probability & false alarm rate Energy efficiency Real-time Low cost Solution: In-network processing in a multitier network WINS Tiered rchitecture Tiers Low-power sensors provide continuous vigilance Seismic, infared, sound High-power sensors sensors Cameras Human operators (most expensive!) Phased execution Low tier activate higher tier when necessary Stop as soon as certainty threshold is reached Power efficiency & reliability CSE 521S 19 CSE 521S 20 Medical Care CodeBlue CodeBlue Requirements Security & privacy Reliability Real-time Sudden change in patient conditions high priority Mobility: Doctors, patients, equipments CSE 521S 21 CSE 521S 22 Structural Health Monitoring Wisden Data collection for structural analysis utonomous health monitoring, warning, and even actuation Wisden Structural Monitoring High sampling frequency tri-axial accelerometer: 100 Hz sampling 4.8 Kbps Reliable data transfer Data synchronization Soft real-time: due to storage limit of sensors CSE 521S 23 CSE 521S 24 4

5 Diverse Requirements Requirements are highly application-dependent Need to optimize design for specific applications Real-time Security Reliability Energy GDI None None None Very Low WINS High High High Low CodeBlue High High High Medium Wisden Medium None High High Summary Small-scale sensor networks have been deployed successfully in the real world Tiered architecture is common Sensing, communication Diverse, application-specific challenges Energy, management, mobility, real-time, reliability, security, privacy CSE 521S 25 CSE 521S 26 Reminders First critique is due on 11:59pm, Sunday Start thinking about project topics Look at existing applications/projects Think about ideas Check out sensor boards Talk to me Good Critique Given that TO is an extension of CORB s full specifications, does the increased size of the TO system limit its usage. Is TO efficient and small enough to be used in hand-held devices? Is it necessary for Real-Time systems to use all of CORB s functionality? Would it be preferable to use a subset of CORB? CSE 521S 27 CSE 521S 28 5