School of Engineering Department of Computer Science and Engineering 131 Parameterized Algorithms for Static Program Analysis Supervisor: KAFSHDAR GOHARSHADY Amir / CSE Student: WU Zhiang / COSC Course: UROP2100, Summer Treewidth is a popular parameter to tackle some practical NP-hard problems. Optimal cache management is one classical problem in the area of programming language and verification. Parameterized complexity is dramatically helpful for those classical hard problems, which always gives a way to solve the problem with better time complexity. In recent topics such as optimal mining for Bitcoin miners, the method of tree decomposition also improves the algorithm efficiency. In this UROP, we first have a rough understanding of how to use tree decomposition and then try to come up with an algorithm to compute reference affinity by designing a nice tree decomposition. Data Mining in Bitcoin Transaction Data Supervisor: LUO Qiong / CSE Student: KOON Tsz Hin / QFIN Course: UROP1100, Summer The Bitcoin network experienced a rapid growth since its introduction by Satoshi Nakamoto in 2008. In recent months, the sky-rocketing adoption and price increment of the Bitcoin attracted wide attention. In this study we extract blockchain data through running a Bitcoin full node and attempt to provide a general picture of the network. We then discuss our and highlighted our key findings in Difficulty, which is found to be an algorithm-based parameter that stabilizes the block generating rate of the decentralized network; SegWit, which introduces us the new concept of block weight and found to be scaling up the network and Patoshi Pattern, which demonstrates an unusual mining pattern in the early blocks. Analysis and Understanding of User Behaviors in Online Communities Supervisor: MA Xiaojuan / CSE Student: MOK Nga Yiu / SENG Course: UROP1100, Summer During the COVID-19 pandemic in the early 2020, there were numerous patients decided to seek help online, especially on Sina Weibo. This study classified the types of posts into four genres, while identifying the channels help-seekers utilized when posting. Thereby suggesting most of the patients intended to post their help-seeking posts on the help seeking super topic, however, some users may fail to do so, resulting misused help seeking super topics. This study also evaluates the differences between different channels, and hence suggested that help seeking super topic might be the best channel during the severe pandemic after evaluating different channels.