1st Edition

Collaborative Filtering Recommender Systems

By Angshul Majumdar Copyright 2025
    141 Pages 10 B/W Illustrations
    by CRC Press

    This book dives into the inner workings of recommender systems, those ubiquitous technologies that shape our online experiences. From Netflix show suggestions to personalized product recommendations on Amazon or the endless stream of curated YouTube videos, these systems power the choices we see every day.

    Collaborative filtering reigns supreme as the dominant approach behind recommender systems. This book offers a comprehensive exploration of this topic, starting with memory-based techniques. These methods, known for their ease of understanding and implementation, provide a solid foundation for understanding collaborative filtering. As you progress, you’ll delve into latent factor models, the abstract and mathematical engines driving modern recommender systems.

    The journey continues with exploring the concepts of metadata and diversity. You’ll discover how metadata, the additional information gathered by the system, can be harnessed to refine recommendations. Additionally, the book delves into techniques for promoting diversity, ensuring a well-balanced selection of recommendations. Finally, the book concludes with a discussion of cutting-edge deep learning models used in recommender systems.

    This book caters to a dual audience. First, it serves as a primer for practicing IT professionals or data scientists eager to explore the realm of recommender systems. The book assumes a basic understanding of linear algebra and optimization but requires no prior knowledge of machine learning or programming. This makes it an accessible read for those seeking to enter this exciting field. Second, the book can be used as a textbook for a graduate-level course. To facilitate this, the final chapter provides instructors with a potential course plan.

     

    Foreword

    Preface

    Author  

    Chapter 1 Introduction and Organization 

    1.1 Introduction

    1.2 Contents of This Book

    Chapter 2 Neighborhood-Based Models

    2.1 Introduction

    2.2 User-Based Approach

    2.3 Item-Based Approach

    Chapter 3 Ratings

    3.1 Introduction

    3.2 Biases and Baseline Correction 

    3.3 Significance Weighting 

    3.4 Optimally Learned Interpolation Weights 9vi Contents

    Chapter 4 Latent Factor Models 

    4.1 Introduction

    4.2 Latent Factor Model

    4.3 Nuclear Norm Minimization

    Chapter 5 Using Metadata

    5.1 Introduction

    5.2 Matrix Factorization on Graphs 

    5.3 Nuclear Norm Minimization on Multiple Graphs 

    5.4 Label-Consistent Nuclear Norm Minimization 

    5.5 Label-Consistent Matrix Factorization

    Chapter 6 Diversity in Recommender Systems

    6.1 Introduction 81

    6.2 Prior Art

    6.3 Matrix Factorization-Based Diversity Model

    6.4 Nuclear Norm-Based Diversity Model

    Chapter 7 Deep Latent Factor Models

    7.1 Introduction

    7.2 Brief Introduction to Representation Learning

    7.3 Deep Latent Factor Model

    7.4 Graphical Deep Latent Factor Model

    7.5 Diversity in Deep Latent Factor Model

    Chapter 8 Conclusion and Note to Instructors

    8.1 Introduction

    8.2 Course Organization

    8.3. Expectation from Pupils

    8.4 Evaluation

     

     

    Biography

     

    Angshul Majumdar is currently a professor at TCG CREST, Kolkata. Prior to that he was a professor at Indraprastha Institute of Information Technology, Delhi, India. He has been associated with the institute since 2012. Angshul did his Master’s (2009) and PhD (2012) in electrical and computer engineering from the University of British Columbia, Vancouver, Canada.

    Angshul’s research interests lie in signal processing and machine learning with applications  in smart grids and bioinformatics. Angshul has co-authored over 200 articles in journals and top tier conferences. He has written two books and co-edited two more and holds 7 US patents. He is an associate editor for IEEE Open Journal for Signal Processing and Elsevier Neurocomputing. In the past, he has been an associate editor for IEEE Transactions on Circuits and Systems for Video Technology.

    Angshul is currently the director of student services at IEEE Signal Processing Society. Prior to that he was the chair for the education committee in the IEEE SPS membership board (2019). Angshul has also served as the chair for the chapter’s committee in the IEEE SPS membership board (2016-18). He had been the founding chair of IEEE SPS Delhi Chapter (2015-18). Angshul has been the organizing chair of two IEEE SPS Winter Schools in 2014 and 2017. He has served as the finance chair of IEEE ISBA 2017, the flagship conference of IEEE Biometrics Council.