Outline 1 What is Robustness? a Profile Injection Attacks Relevance of robustness a Measuring Robustness 2 Attack Strategies a Attacking kNN Algorithms 3 Attack Detection PCA-based Attack Detection Statistical Attack Detection ■Cost- Benefit Analysis 4 Robustness of Model-based AlgorithmsTutorial on Robustness of Recommender Systems Outline 1 What is Robustness? Profile Injection Attacks Relevance of Robustness Measuring Robustness 2 Attack Strategies Attacking kNN Algorithms 3 Attack Detection PCA-based Attack Detection Statistical Attack Detection Cost-Benefit Analysis 4 Robustness of Model-based Algorithms 5 Attack Resistant Recommendation Algorithms Provably Manipulation Resistant Algorithms 6 Stability, Trust and Privacy RecSys 2011: Tutorial on Recommender Robustness