6 Composition of the Recommendation Set 115 6.1 Exploration vs. exploit ation control 117 6.1.1 Design 117 6.1.2 Implement ation 119 6.1.3 Experiments 6.1.4 Related work 126 6.2The“ Slider” interface 6.2.1 Design 6. 2.2 Implement ation 147 148 6.2.4 Observations 6. 2.5 Related work 154 6.2.6 Discussion 6.3 Summary: Deciding on composition 156 7 Conclusions 159 7.1 Future directions for recommender systems 7. 2 Contributions revisited 161 Bibliography 1656 Composition of the Recommendation Set 115 6.1 Exploration vs. exploitation control . . . . . . . . . . . . . . . . . . . 117 6.1.1 Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 6.1.2 Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . 119 6.1.3 Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120 6.1.4 Related work ........................... 126 6.2 The \Slider" interface .......................... 128 6.2.1 Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129 6.2.2 Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . 147 6.2.3 Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148 6.2.4 Observations ........................... 150 6.2.5 Related work ........................... 154 6.2.6 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155 6.3 Summary: Deciding on composition . . . . . . . . . . . . . . . . . . . 156 7 Conclusions 159 7.1 Future directions for recommender systems . . . . . . . . . . . . . . . 160 7.2 Contributions revisited . . . . . . . . . . . . . . . . . . . . . . . . . . 161 Bibliography 165 xii