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This study presents a refined framework for detecting outliers and generating rules from unlabeled data, particularly in network intrusion detection. The focus is on improving the SmartSifter algorithm's accuracy by integrating a probabilistic model and online learning algorithms. We explore the methodology behind SmartSifter and the rule generation process using DL-ESC/DL-SC approaches. Experimental results using the KDD Cup 1999 dataset demonstrate enhanced detection capabilities. This framework aims to identify common patterns among outliers, making the detection process both effective and comprehensible for users.
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Discovering Outlier Filtering Rules from Unlabeled Data Author: Kenji Yamanishi & Jun-ichi Takeuchi Advisor: Dr. Hsu Graduate: Chia- Hsien Wu
Outline • Motivation • Objective • Introduction • Main Framework • Outlier Detector - SmartSifter • Rule Generator – DL-ESC/DL-SC • Experimentation–The network intrusion • Experimental Results • Conclusion • Opinion
Motivation • The problem of the SmartSifter’s accuracy • The SmartSifter cannot find the general pattern of the identified outliers
Objective • Improving the accuracy of SmartSiFter. • Discovering a new pattern that outliers in a specific group may commonly have
Introduction • Developing SmartSifer : It is an on-line outlier detection algorithm • Improving the power of the SamtSifer by combining supervised learning method
Main Framework A New Rule Classifier L
Outlier Detector - SmartSifter ->SS • Using a probabilistic (Gaussian mixture) model->P(x,y) = p(x)p(y|x) • Employing an on-line discounting learning algorithm (SDLE)/(SDEM) to update the model • Giving a score to each datum
Outlier Detector - SmartSifter ->SS (cont.) • SDLE algorithm: An on-line discounting variant of the Laplace law based estimation algorithm • SDEM algorithm: An on-line discounting variant of the incremental EM (Expectation Maximization) algorithm
Outlier Detector - SmartSifter ->SS (cont.) • Outputting a sorted dataset • A highly scored data indicates a high possibility be an outlier
Rule Generator – DL-ESC/DL-SC • Using a stochastic decision list • Employing the principle of minimizing extended stochastic complexity or stochastic complexity
Rule Generator – DL-ESC/DL-SC (cont.) • If ξ makes t1 true, then μ = v1 with probability p1 else if ξ makes t2 true, then μ = v2 with probability p2 ……………………… else μ = vs with probability ps
Experimentation - Network intrusion detection • The purpose of our experiment is to detect without making use of the labels concerning intrusions
Experimentation – Dataset (cont.) • Using the dataset KDD Cup 1999 prepared for network intrusion detection • Using the 13 attributes for DL-ESC • Using four attributes for SmartSifter (service ,duration ,src_bytes ,dst_bytes) • Only “service” is categorical • Y= log(x+0.1),where the base of logarithm is e • Generating five datasets S0,S1,S2,S3,S4
Experimentation – Illustration by an Example (cont.) First Rule – S1 Update Rule – S1 Update Rule – S2
Experimental Results • SS : SmartSifter • R&S: Rule and SmartSifter (This framework) • Using S0 as a training set to construct a filtering rule, each of S1,S2,S3,and S4 is used for test
Conclusion • This new framework has two features • Improving the power of SmartSifter • Helping the user discovers a general pattern
Opinion • Making the detection process more effective and more understandable • This framework can apply to other field