UROP Proceedings 2021-22

School of Engineering Department of Computer Science and Engineering 126 Efficient Queries over Database Supervisor: WONG Raymond Chi Wing / CSE Student: KWAK Byeunggon / COMP Course: UROP1100, Spring Shortest path index maintenance in dynamic road networks is a problem of designing an oracle that supports the shortest path query efficiently where weights of edges change over time. Dynamic shortest path query is an important operation for various network applications since many real-life networks evolve dynamically. Recently, dynamic contraction hierarchy algorithms achieved improved performance in query processing and index maintenance time compared to other existing algorithms. Particularly, Update Efficient, with randomization techniques, showed favorable theoretical time bounds of (log3 ) update time with high probability. Nonetheless, shortcut-centric contraction hierarchy outperformed Update Efficient in experimental evaluations, it did not provide theoretical time bounds. In this report, I will analyze the theoretical time bound of the shortcut-centric paradigm using the techniques provided in the analysis of Update Efficient. Efficient Queries over Database Supervisor: WONG Raymond Chi Wing / CSE Student: LAU Yan Hei / COMP Course: UROP1100, Fall Session-based recommendation is a task that requires the prediction of a user’s next action based on their previous actions. Conventional methods such as nearest-neighbors and markov chains do not show competent results since they fail to capture all the relational information about items. More advanced methods such as Convolutional Neural Networks and Recurrent Neural Networks show promising results as they are able to use more of the information provided. However, state of the art methods utilize Graph Neural Networks to achieve more context aware systems that outperform all other models. The following report will briefly introduce the structures and purposes of GNNs, and will then provide a summary of three papers on session-based recommendation.