This problem is about detecting anomalous nodes in a sensor network. Using GSPBox, create a 60-node random sensor network and define a signal f on the graph as

Question

where c = 0.1 is a constant and d (i, j) is the distance between nodes i and j (can be found

using Dijkstra’s shortest path algorithm). This signal can be thought of as temperature values

in a geographical area, since the variations in temperature values are not high if the sensors are

placed densely. Now introduce some anomaly in the graph signal by making the temperature

values zero for sensors 18 and 39.

In Problem 12 of Chapter 10, the anomaly can be detected using GFT; however, one could not

locate the anomalous nodes. Use SGWT to find the anomalous nodes from the temperature

data you created. Write down the step-by-step procedure and explain why your procedure

works.

Answer 1

This problem is a computer-based exercise. You may use an appropriate software such Matlab
for solving this problem. Some useful code fractions can be found at the support website:
https://complexnetworksbook.github.io