1. CISB422 Sensor Networks

2.  Definition:  Wiki: consists of spatially distributed autonomous sensors to monitor physical or environmental conditions, such as temperature, sound, pressure, etc. and to cooperatively pass their data through the network to a main locationautonomous sensorstemperaturesoundpressure  Key to gathering information needed by smart environments

3. Sensor An object which performs sensing task

4. Sensing Technique to gather information about physical object or processes including the occurrences of events

5.  Sensor  A device that detects a change in a physical stimulus and turns it into a signal which can be measured or recorded  Transducer  A device that transfers power from one system to another in the same of different form

8.  Which sensor for which application?  Stimulus, specifications, physical phenomenon, conversion mechanism, material and application  Stimulus ▪ Acoustic, electric, magnetic, optical, thermal, mechanical  Physical property to be monitored ▪ Temperature, chemical, light, humidity, position, motion  Active  Require external power supply  Passive  Detect energy and derive power from the energy input

9. Physical PropertySensor TemperatureThermocouple Silicon Resistance temperature detector (RTD) Thermistor Force/PressureStrain Gauge Piezoelectric AccelerationAccelerometer FlowTransducer Transmitter PositionLinear Variable Differential Transformers (LVDT) Light IntensityPhotodiode

10.  Networks of nodes that sense and potentially also control their environment. They communicate the information through wireless links “enabling interaction between people or computers and the surrounding environment”  Verdone et all, 2008

11.  A collection of small randomly dispersed devices that provide 3 main functions:-  Ability to monitor physical and environmental conditions (real time)  Ability to operate devices that control the conditions  Ability to provide efficient, reliable communications via wireless network

13.  Defense Advanced Research Projects Agency (DARPA)  1978: Distributed Sensor Nets Workshop  Early 1980s: ▪ Distributed Sensor Networks (DSN) ▪ Sensor Information Technology (SensIT) program

14.  Rockwell Science Center, UCLA  1996: Low Power Wireless Integrated Microsensor (LWIM)  UC Berkeley  Smart Dust project (motes)  Berkeley Wireless Research Center  Low-power sensor device  MIT  μAMPS project-low power hardware and software components for sensor nodes

15.  Network Topology  Communication Protocols and Routing  Sensor Node Architecture

16.  Point to Point  Star  Mesh  Extended Star

17.  Routing protocols depends on:  Power and resource limitations of the network nodes  Time-varying quality of the wireless channel  Possibility for packet loss and delay  First class:  Flat network architecture: all nodes are peers  Second class  Structured: nodes are organized in clusters based on residual energy  Third class  Data-centric approach to disseminate interest: attribute based naming  Fourth class  Uses location to address a sensor node

18.  Low Energy Adaptive Clustering Hierarchy (LEACH)  Clustering-based protocol  Utilizes randomized rotation of the cluster-heads to evenly distribute the energy load among sensor nodes in the network  Assume base station is fixed and far from sensors, all nodes are homogenous and energy- constrained

19.  Power Efficient Gathering in Sensor Information System (PEGASIS)  Chain-based power efficient protocols based on LEACH  Near optimal ▪ All nodes have location information about all other nodes and each has the capability of transmitting data to base station directly ▪ Sensor nodes are immobile

20.  Threshold Sensitive Energy Efficient Sensor Network (TEEN)  Cluster based routing protocol  Network is composed of a base station and sensor nodes with the same initial energy  Base station has a constant power supply and can transmit with high power to all the nodes directly

21.  Flooding and Gossiping  Simple, less maintenance  Each node which receives data sends the packet to its neighbors

23.  IEEE 1451  WirelessHart  ZigBee / 802.15.4  ZigBee IP  6LoWPAN

24.  Energy  Self-Management  Wireless Networking  Decentralized Management  Design Constraints  Security  Others

25.  Ad Hoc Deployment  No predetermined and engineered locations of individual sensor nodes  Unattended Operation  Operate without human intervention: configuration, adaptation, maintenance, repair must be performed autonomously  Self organization: network’s ability to adapt configuration parameters based on system and environmental state  Self optimization: device’s ability to monitor and optimize the use of its own resources  Self protection: device’s ability to recognize and protect itself from intrusions and attacks  Self healing: device’s ability to discover, identify, react to network disruptions

26.  Attenuation: RF signal fades  Larger distance between base station and sensor node requires more transmission power  Must support multi-hop communications and routing

27.  Due to large scale and energy constraint  Results are not optimal, but more energy efficient

28.  Sensitive information  Exposed to malicious intrusions and attacks  Wireless:-eavesdrop on sensor transmission  Denial of service attack  Use of jamming attack: high powered wireless signals are used to prevent successful sensor communications

29. Traditional NetworksWireless Sensor Networks General purpose design; serving many applications Single purpose design, serving one specific application Typical primary design concerns are network performance and latencies; energy is not a primary concern Energy is the main constraint in the design of all node and network components Networks are designed and engineered according to plans Deployment, network structure, and resource use are often ad hoc Devices and networks operate in controlled and mild environments Sensor networks often operate in environments with harsh conditions Maintenance and repair are common and networks are easy to access Physical access to sensor nodes is often difficult and even impossible Component failure is addressed through maintenance and repair Component failure is expected and addressed in the design of the network Obtaining global network knowledge is typically feasible and centralized management is possible Most decisions are made localized without the support of a central manager

30.  Applications:  Air, soil and water monitoring  Condition based maintenance  Habitat monitoring  Seismic detection  Military surveillance  Inventory tracking  Smart spaces

31.  Structural Health Monitoring  Traffic Control  Health Care  Pipeline monitoring  Precision Agriculture  Active Volcano  Underground Mining  Smart City

33.  Heating, ventilation, and air conditioning systems (HVAC)  Lightning  Shading  Air quality and window control  Systems switching off devices  Metering (covered in the section on smart grids)  Standard household applications (e.g. televisions, washing machines)  Security and safety (access control).

35.  Consumes 30% less energy than traditional skycrappers  Has a curtain wall-serves as sunscreen and changes color during the day  Shading system-tracks the sun position and relies on sensor network to automatically actuate the raising and lowering of the shades  HVAC system is equipped with temperature sensors; rely on free air cooling

36.  Temperature sensors and heat detectors  Light level detectors  Movement and occupancy sensors  Smoke and gas detectors  Status sensors (e.g. air quality, open windows)  Glass break sensors

37.  Plant/crop monitoring  Soil monitoring  Climate monitoring  Insect-disease-weed monitoring  Example:  Low Frequency Array (LOFAR) Agro Project ▪ Measured micro climate in a potato field to provide information on how to fight fungal disease and phytophra