Upload
erick-gaines
View
219
Download
0
Tags:
Embed Size (px)
Citation preview
Distributed Algorithms for Mobile Sensor Networks
Ben Miller
A distributed algorithm is a type of parallel algorithm
They are designed to run on multiple interconnected processors
Separate parts of the algorithm are run simultaneously on independent processors
What is a Distributed Algorithm?
What is a Distributed Algorithm? Each of the processors has its own memory
The processors send messages to each other
Wireless Sensor Networks are made up of a series of distributed sensors
The sensors collect data and pass it through the network
The sensors are designed to consume very little power
Wireless Sensor Networks
Wireless Sensor Networks Each sensor node typically consists of a
microcontroller, radio, and battery
Golden Gate Bridge◦ Accelerometers are used to collect data on the
bridge’s movement to monitor its structural health
◦ Researchers at the University of California at Berkeley used 64 sensor nodes to monitor vibrations
Applications
Volcano Monitoring◦ Sensors can be used to observe seismic events
◦ Nodes compare when they observe events to determine their location
◦ Allows geologists to collect data from large areas that are dangerous and difficult to access
Applications
◦ Researchers from Harvard used a network of 16 sensors to monitor a volcano in Ecuador.
◦ In a period of 19 days, they recorded 229 earthquakes, eruptions, and other seismic events
Applications
Datacenter Provisioning◦ Datacenters use a lot of energy and the
computers produce a lot of heat
◦ Wireless Sensor Networks allow datacenters to determine which machines need cooling
◦ Making these dynamic adjustments can greatly reduce power consumption
Applications
Other applications include:◦ Environment and habitat monitoring◦ Wildfire detection◦ Battlefield surveillance
Wireless Sensor Networks have become a popular research area in computer science due to the wide range of applications
Applications
One of the challenges in the field of sensor networks is the deployment of the sensors
The sensors must be properly spaced
If the sensors are too close to each other they won’t cover the entire area of interest
If the sensors are too far apart the coverage regions won’t overlap and the network could become partitioned
A Distributed Algorithm for Mobile Sensor Networks
Inspired by the equilibrium of molecules, which minimizes electronic energy
Each node tries to find its lowest energy point
When each node has found its lowest energy point, the nodes should be uniformly spread across the area of interest
Distributed Self-Spreading Algorithm
A node’s movement is based on the combined forces acting on it due to its neighboring nodes.
Distributed Self-Spreading Algorithm
The algorithm has 4 parts: 1: Initialization 2: Partial Force Calculation 3: Oscillation Check 4: Stability Check
Parts 2,3, and 4 repeat until the node stops moving
Distributed Self-Spreading Algorithm
Step 1: Initialization Initial locations and sensing
ranges are initialized
Local density is the number of nodes within its cR
Expected density is the number of nodes required to cover the entire area when the nodes are deployed uniformly
Step 2: Calculate Force The force depends on the
distance between the nodes and the node’s current local density
High local density will cause the force to be high
Oscillation is when a node is moving back and forth in the same spot
Counts the number of oscillations, if it is over the limit the node stops
Step 3: Calculate Oscillation
Step 4: Stability If a node moves less
than the threshold during the time duration, stability_limit,
the node is considered to be in its final position
Each node goes through the four steps until it stops moving. This results in the sensors being uniformly distributed.
The movement of each node is affected by the position of its neighboring nodes. If one node moves, the surrounding nodes will also move to maximize coverage and uniformity
Distributed Self-Spreading Algorithm
Mobile Data Gathering
Other Distributed Algorithms
Mobile Sensor Networks are a rapidly growing field with a wide range of applications
As distributed systems, like sensor networks, continue to become more popular, the demand for distributed algorithms will increase
Conclusion
Golden Gate Bridge Study: S. Kim, S. Pakzad, D. Culler, J. Demmel, G. Fenves, S. Glaser, and M. Turon. Health monitoring of
civil infrastructures using wireless sensor networks. In IPSN ’07: Proceedings of the 6th international conference on Information processing in sensor networks, 2007
Volcano Study: G. Werner-Allen, K. Lorincz, J. Johnson, J. Leess, and M. Welsh. Fidelity and yield in a volcano monitoring sensor network. In 7th USENIX Symposium on Operating Systems Design and Implementation (OSDI), 2006.
Lenzen, Christoph. "Distributed Algorithms for Sensor Networks." Hebrew University of Jerusalem . Zhao, Miao and Yang, Yuanyuan. “Optimization-Based Distributed Algorithms for Mobile Data
Gathering in Wireless Sensor Networks.”
Heo, and Varshney. “Energy-Efficient Deployment of Intelligent Mobile Sensor Networks” http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.307.4273&rep=rep1&type=pdf
Sources