  Fuzzy Rule Interpolation (FRI) methods can serve deducible (interpolated)
conclusions even in case if some situations are not explicitly defined in a
fuzzy rule based knowledge representation. This property can be beneficial in
partial heuristically solved applications; there the efficiency of expert
knowledge representation is mixed with the precision of machine learning
methods. The goal of this paper is to introduce the benefits of FRI in the
Intrusion Detection Systems (IDS) application area, in the design and
implementation of the detection mechanism for Distributed Denial of Service
(DDOS) attacks. In the example of the paper as a test-bed environment an open
source DDOS dataset and the General Public License (GNU) FRI Toolbox was
applied. The performance of the FRI-IDS example application is compared to
other common classification algorithms used for detecting DDOS attacks on the
same open source test-bed environment. According to the results, the overall
detection rate of the FRI-IDS is in pair with other methods. On the example
dataset it outperforms the detection rate of the support vector machine
algorithm, whereas other algorithms (neural network, random forest and decision
tree) recorded lightly higher detection rate. Consequently, the FRI inference
system could be a suitable approach to be implemented as a detection mechanism
for IDS; it effectively decreases the false positive rate value. Moreover,
because of its fuzzy rule base knowledge representation nature, it can easily
adapt expert knowledge, and also be-suitable for predicting the level of degree
for threat possibility.
