By: Ziji Song Advisor: Prof. J. Spinelli EER Senior Project Wireless Sensor Placement in Arbitrary 3D Environment By: Ziji Song Advisor: Prof. J. Spinelli

Origin and Application of the Problem Union Outing Club students were trapped in a cave during caving due to water flooding Application: Wireless network setup

Goal of the Project For any given 3D environment, setup a wireless sensor network in the environment based on its shape and the communication range of the sensor. Use different algorithms to place motes and compare the different results

Design Specifications All empty spaces in the environment should be reached by at least one sensor mote The least number of sensor motes should be used

Description of the 3D Environment The 3D Environment  “Cave” Cave is divided into nodes which are separated by x,y and z paralleled planes (i.e a 3*3*3 cave will look like a Rubic’s cube) Empty spaces nodes “Free Space Nodes” (refer to the center point of the cube area) Non-empty space nodes  “Rock”

Neighbor Density Definition: For a given free space node in the cave, denote Q as the set of free space nodes which direct lines between p and Q maps only free space nodes. The neighbor density of p equals ∑1/dist2(p,q) for all q in Q.

2D Example of Calculating ND

Another 2D Example with Rock

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

Two Algorithms to Place Motes The First Algorithm Adding motes to an empty cave Add motes to the uncovered node with highest ND Repeat step 2 until all FS nodes are covered

Two Algorithms to Place Motes The Second Algorithm Subtracting motes from a fully occupied cave Place all FS nodes in an array and sort the array ASC with respect to ND For each node in the array, remove the sensor If not all FS nodes are covered, put the sensor back on that particular FS node

Comparison of the Two Methods Run time Simulation results

Conclusion No known algorithm to find the optimal solution Run Time might go up exponentially Both algorithms give reasonable solutions

Special Thanks Prof. Chang Prof. Fernandes Prof. Almstead Prof. Hedrick