EER Senior ProjectEER Senior ProjectWireless Sensor PlacementWireless Sensor Placementin Arbitrary 3D Environmentin Arbitrary 3D Environment

By: Ziji SongBy: Ziji Song

Advisor: Prof. J. SpinelliAdvisor: Prof. J. Spinelli

Origin and Application of the Origin and Application of the ProblemProblem

Origin:Origin:

Union Outing Club students were trapped Union Outing Club students were trapped in a cave during caving due to water in a cave during caving due to water floodingflooding

Application:Application:

Wireless network setupWireless network setup

Goal of the ProjectGoal of the Project

For any given 3D environment, setup a For any given 3D environment, setup a wireless sensor network in the wireless sensor network in the environment based on its shape and the environment based on its shape and the communication range of the sensor. communication range of the sensor.

Use different algorithms to place motes Use different algorithms to place motes and compare the different resultsand compare the different results

Design SpecificationsDesign Specifications

All empty spaces in the environment All empty spaces in the environment should be reached by at least one sensor should be reached by at least one sensor motemote

The least number of sensor motes should The least number of sensor motes should be usedbe used

Description of the 3D EnvironmentDescription of the 3D Environment

The 3D Environment The 3D Environment “Cave” “Cave”

Cave is divided into nodes which are separated Cave is divided into nodes which are separated by x,y and z paralleled planes (i.e a 3*3*3 cave by x,y and z paralleled planes (i.e a 3*3*3 cave will look like a Rubic’s cube)will look like a Rubic’s cube)

Empty spaces nodesEmpty spaces nodes “Free Space Nodes” “Free Space Nodes” (refer to the center point of the cube area)(refer to the center point of the cube area)

Non-empty space nodes Non-empty space nodes “Rock” “Rock”

Neighbor DensityNeighbor Density

Definition: For a given free space node in Definition: For a given free space node in the cave, denote Q as the set of free the cave, denote Q as the set of free space nodes which direct lines between p space nodes which direct lines between p and Q maps only free space nodes. The and Q maps only free space nodes. The neighbor density of p equals ∑1/distneighbor density of p equals ∑1/dist22(p,q) (p,q) for all q in Q.for all q in Q.

2D Example of Calculating ND2D Example of Calculating ND

Another 2D Example with RockAnother 2D Example with Rock

Important DefinitionsImportant Definitions

Covered Node: If a free space node is Covered Node: If a free space node is reachable by at least one sensor mote, reachable by at least one sensor mote, then it is a covered node. then it is a covered node. Occupied Node: If a sensor mote is placed Occupied Node: If a sensor mote is placed on a free space node, then the node is on a free space node, then the node is occupied.occupied.

Two Algorithms to Place MotesTwo Algorithms to Place Motes

The First AlgorithmThe First AlgorithmAdding motes to an empty caveAdding motes to an empty cave Add motes to the uncovered node with Add motes to the uncovered node with

highest NDhighest ND Repeat step 2 until all FS nodes are coveredRepeat step 2 until all FS nodes are covered

Two Algorithms to Place MotesTwo Algorithms to Place Motes

The Second AlgorithmThe Second AlgorithmSubtracting motes from a fully occupied caveSubtracting motes from a fully occupied cave Place all FS nodes in an array and sort the array Place all FS nodes in an array and sort the array

ASC with respect to NDASC with respect to ND For each node in the array, remove the sensorFor each node in the array, remove the sensor If not all FS nodes are covered, put the sensor If not all FS nodes are covered, put the sensor

back on that particular FS nodeback on that particular FS node

Comparison of the Two MethodsComparison of the Two Methods

Run timeRun time

Simulation resultsSimulation results

ConclusionConclusion

No known algorithm to find the optimal No known algorithm to find the optimal solutionsolution

Run Time might go up exponentiallyRun Time might go up exponentially

Both algorithms give reasonable solutions Both algorithms give reasonable solutions

Special ThanksSpecial Thanks

Prof. ChangProf. Chang Prof. FernandesProf. Fernandes

Prof. AlmsteadProf. Almstead Prof. HedrickProf. Hedrick