Wormhole Detection Based on Ordinal MDS Using RTT in Wireless Sensor Network

Algorithm 2

Steps of ordinal MDS algorithm for suspect node set.

Input: Shortest distance matrix/Dissimilarity matrix

Output: Suspect node set

 Each node is assigned an arbitrary initial location as

 Set the threshold value for Stress1 measure

 Set iteration counter

 Compute Euclidean distance between each node pair to generate virtual distance matrix

 Apply monotone regression using PAV algorithm on and to calculate disparity and get intermediate matrix

 if   and   then

   Add node to the suspect node set

 else

  end if

  Calculate new coordinate for each node using steepest descent method

  Set as proposed by Kruskal [29]

  Recalculate the Euclidean distance of each node pair to update distance matrix

  Calculate the Kruskal’s Stress1 measure

  if  Stress1 >   then

    Set

    Go to step (5)

(22)   else

(23)     Terminate

(24)   end if