Fan Liu

This book covers the principles, methods, and state-of-the-art applications of positioning and sensing across both ground-based and aerial wireless networks. The first two chapters introduce key performance metrics and measurement techniques along with enabling tools. In the next two chapters, this book examines radio-frequency implementations over Wi-Fi systems, followed by visible-light positioning systems. Building on these chapters, fusion-based strategies demonstrate how inertial sensors, floor plans, and environmental constraints can be integrated via adaptive filter to enhance positioning accuracy. Subsequent chapters explore unmanned aerial vehicle–assisted positioning. Finally, this book presents integrated sensing–communication frameworks that design joint UAV Trajectory and resource allocations to deliver simultaneous connectivity and environmental awareness. This book targets graduate-level students and researchers working in computer science and electrical engineering as well as industry engineers. It offers both theoretical foundations and practical guidelines to develop next-generation wireless networks and beyond positioning and sensing solutions.

This book systematically examines scalability and effectiveness challenges related to the application of graph convolutional networks (GCNs) in recommender systems. By effectively modeling graph structures, GCNs excel in capturing high-order relationships between users and items, enabling the creation of enriched and expressive representations. The book focuses on two overarching problem categories: the first area deals with problems specific to GCN-based recommendation models, including over-smoothing, noisy neighboring nodes, and interpretability limitations. The second one encompasses broader challenges in recommendation systems that GCN-based methods are particularly well-suited to address as the attribute missing problem or feature misalignment. Through rigorous exploration of these challenges, this book presents innovative GCN-based solutions to push the boundaries of recommender system design. To this end, techniques such as interest-aware message-passing strategy, cluster-based collaborative filtering, semantic aspects extraction, attribute-aware attention mechanisms, and light graph transformer are presented. Each chapter combines theoretical insights with practical implementations and experimental validation, offering a comprehensive resource for researchers, advanced professionals, and graduate students alike.

This book presents an in-depth exploration of multimodal learning toward recommendation, along with a comprehensive survey of the most important research topics and state-of-the-art methods in this area. First, it presents a semantic-guided feature distillation method which employs a teacher-student framework to robustly extract effective recommendation-oriented features from generic multimodal features. Next, it introduces a novel multimodal attentive metric learning method to model user diverse preferences for various items. Then it proposes a disentangled multimodal representation learning recommendation model, which can capture users’ fine-grained attention to different modalities on each factor in user preference modeling. Furthermore, a meta-learning-based multimodal fusion framework is developed to model the various relationships among multimodal information. Building on the success of disentangled representation learning, it further proposes an attribute-driven disentangled representation learning method, which uses attributes to guide the disentanglement process in order to improve the interpretability and controllability of conventional recommendation methods. Finally, the book concludes with future research directions in multimodal learning toward recommendation. The book is suitable for graduate students and researchers who are interested in multimodal learning and recommender systems. The multimodal learning methods presented are also applicable to other retrieval or sorting related research areas, like image retrieval, moment localization, and visual question answering.