2.2.3 USERS'jUDGM ENIS OF DOCUM ENIS 2.2.4 USERPeCfIES 2.2.5 SIM UIATING USERS' DOCUM ENT FANKNG BEHAVIOR 3 EVALUATIONS 2.3.1 RELEVANCE BASED EVALUATION 222333 2.3.2 EVAIUATION USING DISIANCE BETWEN FANK 2.3.3 EXPERIM ENIALM EIHODOIOGY 2. 4 INIEFACIIONS 2.4.1 INP UIS: USER FFEDBAC k 2.4.2 OUIP UIS: RECOM M ENDATION SEIS 42 2.5 SUM MARY OF NCIATION 3 Single Agent Content-B ased recommendation 3.1 DESIGN 3.1.1 colLeCtION 3.12 SELECtiON 3.1.3 LEARNING 3. 2 IMPIEM ENIATION 3. 3 SIM ULATION 3. 4 EXPERIMENIS 3.4.1 CS227 CIASS PRCIECIS 5556 3. 4.2 TESIS OF LIRA 3.43 SIM ULATION HESUIIS 3.5 PHOBIEMS WIH THE PURE CONIENF BASED APPROACH 4 Collaborative recommendation 4.1 DESI 74 4. 2 A BRIEF SUFVEY2.2.3 Users' judgments of documents ................. 25 2.2.4 User proles . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 2.2.5 Simulating users' document ranking behavior ......... 29 2.3 Evaluations ................................ 32 2.3.1 Relevance-based evaluation . . . . . . . . . . . . . . . . . . . . 32 2.3.2 Evaluation using distance between rankings .......... 33 2.3.3 Experimental methodology . . . . . . . . . . . . . . . . . . . . 35 2.4 Interactions ................................ 38 2.4.1 Inputs: user feedback. . . . . . . . . . . . . . . . . . . . . . . 39 2.4.2 Outputs: recommendation sets ................. 42 2.5 Summary of notation . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 3 Single Agent Content-Based Recommendation 45 3.1 Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 3.1.1 Collection ............................. 48 3.1.2 Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 3.1.3 Learning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 3.2 Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 3.3 Simulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 3.4 Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 3.4.1 CS227 Class Pro jects . . . . . . . . . . . . . . . . . . . . . . . 58 3.4.2 Tests of LIRA . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 3.4.3 Simulation results . . . . . . . . . . . . . . . . . . . . . . . . . 65 3.5 Problems with the pure content-based approach ............ 71 4 Collaborative Recommendation 73 4.1 Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 4.2 A brief survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 x