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Basics of Wireless Sensor Network
A sensor network is an infrastructure contain sensing(measuring), computing and communication elementsthat gives an administrator the ability to device toobserve and react to events in a specified environment.
There are four basic components in a sensor network:
An Assembly of distributed or localized sensors An interconnecting network (usually wireless-based) A Central point of information clustering A set of computing resources at the central point to
handle data correlation, event movement, statusquerying & data mining.
The technology for sensing and control includes
Electric and magnetic field sensors; Radio-wave frequency sensors Optical-, electrooptic- and infrared sensors; Radars; lasers; location/navigation sensors; Seismic and pressure-wave sensors; Environmental parameter sensors (e.g., wind, humidity,
heat); Biochemical national security–oriented sensors.
Today’s sensors can be described as ‘‘smart’’ inexpensivedevices equipped with multiple onboard sensing elements;they are low-cost, low-power ,multifunctional nodes.
Sensor devices or wireless nodes (WNs) are also called motes . Sensors are internetworked via a series of multihop short-
distance low-power wireless links
Introduction to Wireless Sensor Networks 4
Wireless Sensor Networks are networks that consists
of sensors which are distributed in an adhoc manner.
These sensors work with each other to sense some
physical phenomenon and then the information
gathered is processed to get relevant results.
Wireless sensor networks consists of protocols and
algorithms with self-organizing capabilities.
“A wireless sensor network (WSN) is a wireless
network consisting of spatially distributed
autonomous devices using sensors to cooperatively
monitor physical or environmental conditions, such
as temperature, sound, vibration, pressure, motion
or pollutants, at different locations.”
- Wikipedia
Formed by hundreds or thousands of motes thatcommunicate with each other and pass data along from oneto another
Research done in this area focus mostly on energy awarecomputing and distributed computing
Super Node
Links to Other networks or
Similar Super Nodes
Motes
Environmental/Habitat monitoring
Acoustic detection
Seismic Detection
Military surveillance
Inventory tracking
Medical monitoring
Smart spaces
Process Monitoring
Energy Efficiency
Limited storage and computation
Low bandwidth and high error rates
Errors are common
◦ Wireless communication
◦ Noisy measurements
◦ Node Failure are expected
Scalability to a Large Number of Sensor Nodes
Introduction to Wireless Sensor Networks 11
Power efficiency in WSNs is generally accomplishedin three ways:
1. Low-duty-cycle operation.
2. Local/in-network processing to reduce data volume
3. Multihop networking reduces the requirement forlong-range transmission since signal path loss is aninverse exponent with range or distance. Each nodein the sensor network can act as a repeater, therebyreducing the link range coverage required and, inturn, the transmission power.
MANET WSNMANETs are based on point-to-pointcommunications.
sensor nodes use primarily multicast orbroadcast communication,
They are mobile Sensors generally are not mobile
this is not generally the casein MANETs.
Because the data being collected by multiplesensors are based on common phenomena,there is potentially a degree of redundancy inthe data being communicated by the varioussources in WSNs;
this is not always the case in MANETs, wherethe communicating devices handled by humanusers can be replaced or recharged relativelyoften.
A critical resource constraint in WSNs isenergy;
The number of sensor nodes in a MANETnetwork are less.
The number of sensor nodes in a sensornetwork can be several orders ofmagnitude higher than the nodes in a MANET.
Sensors ◦ Enabled by recent advances in
MEMS technology◦ Integrated Wireless
Transceiver◦ Limited in
Energy
Computation
Storage
Transmission range
Bandwidth
DAWN Lab / UMBC 14
Battery
Memory
CPU
Sensing Hardware
Wireless
Transceiver
DAWN Lab / UMBC 16
DAWN Lab / UMBC 17
Advanced Techniques of Mobile Ad Hoc and Wireless Sensor Networks
Applications of Sensor Networks
Military applications
Monitoring inimical forces
Monitoring friendly forces and equipment
Military-theater or battlefield surveillance
Targeting
Battle damage assessment
Nuclear, biological, and chemical attack detection
Environmental applications
Microclimates
Forest fire detection
Flood detection
Precision agriculture
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Advanced Techniques of Mobile Ad Hoc and Wireless Sensor Networks
Applications of Sensor Networks continue…
Health applications
Remote monitoring of physiological data
Tracking and monitoring doctors and patients inside a hospital
Drug administration
Elderly assistance
Home applications
Home automation
Instrumented environment
Automated meter reading
Commercial applications
Environmental control in industrial and office buildings
Inventory control
Vehicle tracking and detection
Traffic flow surveillance
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Advanced Techniques of Mobile Ad Hoc and Wireless Sensor Networks22
Roles of participants in WSN
Sources of data: Measure data, report them “somewhere”Typically equip with different kinds of actual sensors
Sinks of data: Interested in receiving data from WSN May be part of the WSN or external entity, PDA, gateway, …
Actuators: Control some device based on data, usually also a sink
Advanced Techniques of Mobile Ad Hoc and Wireless Sensor NetworksDAWN Lab / UMBC23
Network Architectures
Layer 1
Layer 2
Layer 3
Layered
Architecture
Base
Statio
n
Clustered
Architecture
Base
Statio
n
Larger Nodes denote Cluster Heads
Advanced Techniques of Mobile Ad Hoc and Wireless Sensor Networks
Protocol Stack for sensor Network
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Advanced Techniques of Mobile Ad Hoc and Wireless Sensor Networks
WSN Protocol Stack
26
Layer Name Working
Upper layers In-network applications, including application processing, dataaggregation,external querying query processing, and external database
Layer 4 Transport, including data dissemination and accumulation,caching, andstorage
Layer 3 Networking, including adaptive topology management andtopologicalrouting
Layer 2 Link layer (contention): channel sharing (MAC), timing, andlocality
Layer 1 Physical medium: communication channel, sensing, actuation,and signal processing
Advanced Techniques of Mobile Ad Hoc and Wireless Sensor Networks
WSN Sensor types( Categories)
Category 1 WSNs (C1WSNs)
Category 2 WSNs (C2WSNs)
mesh-based systems with multihopradio connectivity among or between WNs
Point-to-point or multipoint-to-point (starbased) systems generally with single-hop radio connectivity to WNs
Utilizing dynamic routing in both the wireless and wireline portions of the network.
Utilizing static routing over the wireless network; typically, there will be only one route from the WNs to the companion terrestrial or wirelineforwarding node
support highly distributed high-node-count applications(e.g., environmental monitoring, national security systems);
C2WSNs typically support confined short-range spacessuch as a home, a factory, a building, or the human body.
C1WSNs tend to deal with large-scalemultipoint-to-point systems with massive data flows, whereas
C2WSN technology for short-range low-data-rate wireless applications such as RFID (radio-frequency identification) systems, light switches, fire and smoke detectors, thermostats, and, home appliances.
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Advanced Techniques of Mobile Ad Hoc and Wireless Sensor Networks
Category-1 WSN Architecture
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Advanced Techniques of Mobile Ad Hoc and Wireless Sensor Networks
Category 2-WSN architecture
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Advanced Techniques of Mobile Ad Hoc and Wireless Sensor Networks
EXAMPLES OF CATEGORY 2 WSN
APPLICATIONS
1. Home Application
2. Building Automation
3. Industrial Automation
4. Medical Application
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Advanced Techniques of Mobile Ad Hoc and Wireless Sensor Networks
Home Control Automation
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Advanced Techniques of Mobile Ad Hoc and Wireless Sensor Networks
Home Control Automation
Sensing applications facilitate management of lighting, heating, and cooling
systems from anywhere in the home.
Sensing applications automate control of multiple home systems to improve
conservation, convenience, and safety.
Sensing applications capture highly detailed electric, water, and gas utility
usage data.
Sensing applications embed intelligence to optimize consumption of natural
resources.
Sensing applications enable the installation, upgrading, and networking of a
home control system without wires.
Sensing applications enable one to configure and run multiple systems from a
single remote control.
Sensing applications support the straightforward installation of wireless
sensors to monitor a wide variety of conditions.
Sensing applications facilitate the reception of automatic notification upon
detection of unusual events.
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Advanced Techniques of Mobile Ad Hoc and Wireless Sensor Networks
Building Automation
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Advanced Techniques of Mobile Ad Hoc and Wireless Sensor Networks
Building Automation
Sensing applications integrate and centralize management oflighting, heating , cooling, and security (e.g., see Figure 2.6).
Sensing applications automate control of multiple systems toimprove conservation, flexibility, and security.
Sensing applications reduce energy expenses
Sensing applications enable one to allocate utility costsequitably based on actual consumption.
Sensing applications enable the rapid reconfiguring oflighting systems to create adaptable workspaces.
Sensing applications enable the extension and upgrading ofbuilding infrastructure with minimal effort.
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Advanced Techniques of Mobile Ad Hoc and Wireless Sensor Networks
Industrial Control Application
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Advanced Techniques of Mobile Ad Hoc and Wireless Sensor Networks
Industrial Control Application
Industrial automation applications provide control, conservation , efficiency, and safety, as follows:
Sensing applications improve asset management by continuous monitoring of critical equipment.
Sensing applications reduce energy costs through optimized manufacturing processes.
Sensing applications help identify inefficient operation or poorly performing equipment.
Sensing applications help automate data acquisition from remote sensors to reduce user intervention.
Sensing applications provide detailed data to improve preventive maintenance programs.
Sensing applications help deploy monitoring networks to enhance employee and public safety.
Sensing applications help data collection for improved compliance reporting.
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Advanced Techniques of Mobile Ad Hoc and Wireless Sensor Networks
Applications for Industrial and Commercial Spaces Include
Warehouses, fleet management, factories, supermarkets,office complexes
Gas, wat Smoke, CO, and HO detectors
Refrigeration cage or appliance
Equipment management services and preventivemaintenance
Security services
Lighting control
Assembly line and workflow and inventory
Materials processing systems (heat, gas flow, cooling,chemical)
Remote monitoring from corporate headquarters of assets,billing, and energy management
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Advanced Techniques of Mobile Ad Hoc and Wireless Sensor Networks
Medical Application
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Advanced Techniques of Mobile Ad Hoc and Wireless Sensor Networks
Medical Application
A number of hospitals and medical centers are exploringapplications of WSN technology to a range of medical applications,including pre-hospital and in-hospital emergency care, disasterresponse, and stroke patient rehabilitation.
WSNs have the potential to affect the delivery and study of care byallowing vital signs to be collected and integrated automaticallyinto the patient care record and used for real-time triage,correlation with hospital records,
WSNs permit home monitoring for chronic and elderly patients,facilitating long-term care and trend analysis;
This in turn can sometimes reduce the length of hospital stays.
WSNs also permit collection of long-term medical information thatpopulates databases of clinical data; this enables studies acrosspopulations and allows physicians to study the effects of medicalintervention programs
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Advanced Techniques of Mobile Ad Hoc and Wireless Sensor Networks
EXAMPLES OF CATEGORY 1 WSN APPLICATIONS
Military sensor networks to detect and gain as much information as possible about enemy movements, explosions, and other phenomena of interest
Law enforcement and national security applications for inimical agent tracking or nefarious substance monitoring (e.g., see Figure 2.9)
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Advanced Techniques of Mobile Ad Hoc and Wireless Sensor Networks
Law enforcement and national security applications
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Advanced Techniques of Mobile Ad Hoc and Wireless Sensor Networks
EXAMPLES OF CATEGORY 1 WSN APPLICATIONS
Sensor networks to detect and characterize chemical,biological, radiological, nuclear, and explosive (CBRNE)attacks and material
Sensor networks to detect and monitor environmentalchanges in plains, forests, oceans, and so on
Wireless traffic sensor networks to monitor vehicle traffic onhighways or in congested parts of a city
Wireless surveillance sensor networks for providing securityin shopping malls, parking garages
Wireless parking lot sensor networks to determine whichspots are occupied and which are free
Borders monitoring with sensors and satellite uplinks
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Advanced Techniques of Mobile Ad Hoc and Wireless Sensor Networks
Highway Monitoring Application
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Advanced Techniques of Mobile Ad Hoc and Wireless Sensor Networks
Highway Monitoring Application
Traffic Pulse is targeted for open-air environments; itprovides real-time collection of data (e.g., to checktemperature or monitor pollution levels).
The system is installed along major highways; the digitalsensor network gathers lane-by-lane data on travel speeds,lane occupancy, and vehicle counts.
These basic data elements make it possible to calculateaverage speeds and travel times.
The data are then transmitted to the data center forreformatting.
In each major city, Traffic.com maintains a traffic pulseoperations center that collects and reports on real-timeevent, construction, and incident data.
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Advanced Techniques of Mobile Ad Hoc and Wireless Sensor Networks
Military Applications
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Advanced Techniques of Mobile Ad Hoc and Wireless Sensor Networks
Military Applications
Condition-Based Monitoring
Military Surveillance
Borders Monitoring
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Advanced Techniques of Mobile Ad Hoc and Wireless Sensor Networks
Civil and Environmental Engineering Applications
Sensors can be used for civil engineering applications.
Research has been under way in recent years to developsensor technology that is applicable for buildings, bridges,and other structures.
The goal is to develop ‘‘smart structures’’ that are able to self-diagnose potential problems and self-prioritize requisiterepairs
This technology is attractive for earthquake-active zones.
Although routine mild tremors may not cause visibledamage, they can give rise to hidden cracks that couldeventually fail during a higher-magnitude quake.
Furthermore, after a mild earthquake, a building’s truestructural condition may be visible through Smart Dustmotes, tiny and inexpensive sensors
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Advanced Techniques of Mobile Ad Hoc and Wireless Sensor Networks
Wildfire Instrumentation Application
Collecting real-time data from wild fires is important for life
safety considerations and allows predictive analysis of
evolving fire behavior.
One way to collect such data is to deploy sensors in the
wildfire environment.
FireBugs are small wireless sensors (motes) based on TinyOS
that self-organize into networks for collecting real-time data
in wildfire environments
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Advanced Techniques of Mobile Ad Hoc and Wireless Sensor Networks
Habitat Monitoring Application
Monitoring of sensitive wildlife and habitats.
About three dozen motes were deployed on the island.
Each mote has a microcontroller, a low-power radio,memory, and batteries.
Sensor motes monitor and relay their readings into a satellitelink that allows researchers to download real-timeenvironmental data over the Internet.
For habitat monitoring the planner needed sensors that cantake readings for temperature, humidity, barometricpressure, and midrange infrared.
Motes sample and relay their sensor readings periodically tocomputer base stations on the island
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