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A Short Bio – Dr. Zhanyang Zhang A Short Bio – Dr. Zhanyang Zhang
Education – Ph.D and MS degrees from CUNY respectively in 1995 and 1988. EE degree from Jilin University, China in 1982
Academic Position – Assistant Professor, Computer Science Department at College of Staten Island (9/2003 – present)
Industry Experience - Full time and consultant positions in telecommunication, finance and pharmaceutical industries (1993-2003)
Areas of Research Interests Areas of Research Interests
Past Research:
• Database, Data Warehouse and Data Mining
• 3G-Wireless Data Network and Wireless Data Network Security
• E-Commerce and M(obile)-Commerce
Current Research:
• Wireless Ad hoc Networks
• Mobile Database
• Wireless Sensor Networks
Wireless Sensor Network Wireless Sensor Network andand
ApplicationsApplications
Zhanyang Zhang, Ph. D
College of Staten Island
City University of New York
Oct 4th, 2004
OutlineOutline
Introduction
Communication architecture
Protocol stack
Applications
Research Problems and Opportunities
A Stimulating Signal Approach toward Sensor Location, K-Coverage and Energy-Saving Problems
IntroductionIntroduction
Sensor Networks…low-cost, rapid deployment, self-organizing, and fault tolerance.
Application areas: heath, military, and home.
Large number of sensor nodes that are densely deployed.
Nodes use their processing abilities to locally carry out simple computations and transmit the required and partially processed data.
Ad hoc networks are not suitable for the sensor networks because of their unique features and application requirements.
Features of Sensor Features of Sensor Networks
What is a Sensor Network? 1000s of sensors deployed to collect, process and store information
e.g. weather conditions.
Local communication to achieve global objectives
Popular application areas – Medical, Military, Natural Habitat monitoring, micro-organisms
monitoring, etc
Factors to consider when deploying sensors– Low power Large numbers Frequent motion, task dynamics / Device failures Distributed sensing Exception free, unattended operation
Design FactorsDesign Factors
Fault Tolerancethe ability to sustain sensor network functionalities without any interruption due to sensor node failures because of lack of power, physical damage, or environmental interference.
Scalabilitythe density of sensor nodes can range from few sensor nodes to few hundred sensor nodes in a region.
Production Coststhe cost of sensor node should be much less than $1 in order for the sensor network to be feasible
Sensor Network Topology- Predeployment and deployment phase- Post-deployment phase- Redeployment of additional nodes phase
Environmentcan work in different environments.
Transmission Medialinks between nodes can be formed by radio, infrared, or optical media.
Power Consumptionbattery lifetimedesign of power-aware protocols and algorithmsPower consumption: sensing, communication, and data processing
Continue.. Design Factors
Hardware Architecture
Power Unit Powergenerator
Location finding system Mobilizer
TransceiverSensor ADC
SensingUnit
ProcessingUnit
Processor
Storage
Communication ArchitectureCommunication Architecture
Internet and Satellite
Sink
Task managernode
User
Sensor nodesSensor field
A
B
CDE
Protocol Stack :- Sensor NetworksProtocol Stack :- Sensor Networks
The Physical LayerThe Physical Layer
Frequency selection.
Carrier frequency generation.
Signal detection.
ModulationBinary and M-ary modulation schemesthe binary modulation scheme is more energy-efficient
Low transmission power and simple transceiver circuitry make Ultra wideband (UWB) an attractive candidate.
The Data Link LayerThe Data Link Layer
Multiplexing of data streams.
Data frame detection.
Medium access and error control.
Ensures reliable point-to-point and point-to-multipoint connections in a communication network.
Medium Access ControlMedium Access Control
Must achieve two goals- the creation of the network infrastructure- share communication resources between sensor nodes fairly and efficiently.
Traditional MAC can’t be adopted into sensor networks, because- there is no central controlling agent like the base station.- power efficiency directly influences network lifetime in sensor network.
Continue.. The Data Link Layer
Network LayerNetwork Layer
Task: energy efficient routes
Sink
A (PA=2)
B (PA=2)
C (PA=2) T
D (PA=3)
E (PA=1)
F (PA=4)
α
1=1
α
α
α
αα
α
α
α
α 5=2
3=2
4=2
2=16=2
7=1
8=2
9=2
Route 1: Sink-A-B-T, total PA=4, total α = 3 Route 2: Sink-A-B-C-T, total PA=6, total α = 6Route 3: Sink-D-T, total PA=3, total α = 4Route 4: Sink-E-F-T, total PA=5, total α = 6
Approaches:• Max route: route 4• Min Energy (ME) route: route 1• Min hop (MH) route: route 3• Max-Min PA node route: route 3
Data Aggregation, data fusionData Aggregation, data fusion
AB C
DE
FG
Sink
Continue.. Network Layer
Routing techniquesRouting techniques
Floodingeach node receiving a data or management packet repeats it by broadcasting.
Gossipingsend the incoming packets to a randomly selected neighbor.
Continue.. Network Layer
Transport LayerTransport Layer
Transport layer protocols are still unexplored: they may be purely UDP-type protocols, because each sensor node has limited memory and power.
The Application Layer Sensor Management Protocol (SMP)
makes the hardware and software of the lower layers transparent to the sensor network management applications. System administrators interact with sensor networks using SMP.
Task Assignment And Data Advertisement Protocol (TADAP)provides the user software with efficient interfaces for interest dissemination.
Sensor Query and Data Dissemination Protocol (SQDDP)provides user applications with interfaces to issue queries, respond to queries and collect incoming replies.
Application - Habitat MonitoringApplication - Habitat Monitoring
Goal – monitor breeding preferences of Leach’s Storm Pretel on Great Duck Island, Maine usage pattern of nesting burrows
changes in the burrow and surface environmental parameters during the breeding season
differences in the micro-environments with and without large numbers of nesting petrels
Habitat Monitoring - SensorsHabitat Monitoring - Sensors
Hardware deployed
32 MICA motes in cases
MICA weather board with sensors – temperature, pressure, etc.
Groups of nodes –Patches
Gateway to transmit data via the transit network to the base station.
Mobile PDA’s – Gizmos, to program the motes in the field.
Setup / Design RequirementsSetup / Design Requirements
Hierarchical network
Network longevity – 9 months
Operating off the grid – other source of energy – Solar
Management from a distance
Stable and predictable system behavior
In-situ interactions with motes
Store data at all levels to prevent data loss
Easy re-tasking facilities
Challenging ProblemsChallenging Problems
Sensor Location Problem – Locating sensor within the deployed area.
K-Coverage Problem – Every point in the monitor area requires at least K sensors to cover it.
Sensor Network Energy Saving – To maximum sensors and/or sensor networks lifetime.
Sensor Data Modeling, Management, and Stream Data Mining
Research OpportunitiesResearch Opportunities
Sensor Location Solutions:
• GPS-Free
• Meet application requirements
• Low overhead (communication, processing, energy consumption)
Previous Works:
• Triangulation
• At least 3 reference nodes with known locations
• Ultra-sound or RF beacons
• Time of Arrival (TOA) or signal strength
• High computation complexity and energy consumption
Research OpportunitiesResearch Opportunities
Sensor Location Solutions:
• GPS-Free
• Meet application requirements
• Low overhead (communication, processing, energy consumption)
Previous Works:
• Triangulation
• At least 3 reference nodes with known locations
• Ultra-sound or RF beacons
• Time of Arrival (TOA) or signal strength
• High computation complexity and energy consumption
Cricket System at MITCricket System at MIT
Current Research ProjectCurrent Research Project
A Stimulating Signal Model
• Sensor’s sensing ability
• Location guided laser beam
• Sensor Cluster Location Algorithm (SCLA)
• Scale Well
• Low overhead (communication, processing, energy consumption)
Limitations
• Open Areas
• Line-of-path
• Estimate Geo-boundary of cluster
Preliminary OutcomePreliminary Outcome
Results
• Identify Sensor Clusters for each virtual grid
• Geo-proximity of Cluster Locations
• Number of members in each Cluster (A potential solution for K-coverage problem for sensor networks)
• Alternate “sleep” and “active” status of Cluster members with a schedule algorithm to prolong sensor network lifetime
Cost Analysis
• Let M be the number grids, N be the max number of sensors in a grid, L be the max number of hops between a cluster header and base station.
• Cost(M,N,L) <= M*N + M*L in terms of messages sent
ReferencesReferences
[1] “Next Century Challenges: Scalable Coordination in Sensor Networks” - Deborah Estrin, Ramesh Govindan, John Heidemann and Satish Kumar, Mobicom 1999.
[2] “A Survey on Sensor Networks” -Ian F. Akyildiz, Weilian Su, Yogesh Sankarasubramaniam and Erdal Cayirci, IEEE Communications Magazine, vol. 40, no. 8, August 2002.
[3] “Wireless Sensor Networks for Habitat Monitoring” -Mainwaring et al., WSNA 2002.
[4] Habitat Monitoring on Great Duck Island
http://www.greatduckisland.net
Questions?Questions?
Thank you!
