A Real-Valued Negative Selection Algorithm Based on Grid for Anomaly Detection

Algorithm 6

The filtering process of candidate detectors.

𝐹𝑖𝑙𝑡𝑒𝑟(𝐶𝐷)

Input: the candidate detector set 𝐶𝐷

Step 1. Sort CD in a descending order by the detector radius;

Step 2. Make sure that centers of detectors in the back of the sequence do not fall into the covered area of front detectors.

   That is to say, 𝑑𝑖𝑠(𝑑_𝑖,𝑑_𝑗)>𝑟_𝑑𝑖, where 1<=𝑖<𝑗<=𝑁_𝑐𝑑,𝑟_𝑑𝑖 is the radius of detector 𝑑_𝑖, and 𝑁_𝑐𝑑 is the size of 𝐶𝐷;

Step 3. Add candidate detectors into 𝐷, and ensure that they do not entirely cover any detector in 𝐷. That is to say,

    𝑑𝑖𝑠(𝑑_𝑖,𝑑_𝑗)>𝑟_𝑑𝑖  or 𝑑𝑖𝑠(𝑑_𝑖,𝑑_𝑗)<=𝑟_𝑑𝑖 and 2𝑟_𝑑𝑗>𝑟_𝑑𝑖, where 1<=𝑖<=𝑁_𝑐𝑑,1<=𝑗<=𝑁_𝑑,𝑟_𝑑𝑖 and 𝑟_𝑑𝑗 are the radiuses

   of 𝑑_𝑖 and 𝑑_𝑗 respectively, and 𝑁_𝑐𝑑 and 𝑁_𝑑 are the sizes of 𝐶𝐷 and 𝐷 respectively.