数 学 与 工 程 的 对 话 中山大学 信息科学与技术学院 李硕彦教授演讲 (10月21, 24日) 李硕彦 ( Bob Li ) 简介: 2011年 10月21日 2-3pm 东校区 软件学院 101讲学厅 报告1: Martingale of patterns (模式的反直覺概率) This talk presents some probability knowledge in elementary terms. Martingale, in layman’s term, means fair gamble. Toss a coin repeatedly until the pattern HTHH appears in a run. The average waiting time is not 16 but rather 18. For the pattern THTH, it is even longer. What are the odds when these two patterns compete against each other? Well, come to this talk for a big surprise. Commonly used tools, such as Markov chains, solve problems about occurrence of patterns through long computation. In contrast, martingale yields the most general result instantly, which offers transparent insight. The main technique is team gambling in combination with the martingale stopping theorem. 10月24日 10:45-11:45am I had a private theory for exponential speed-up in the computation of blackjack probabilities. It applied some algebra of the symmetric group to tree-search computing. I had fun using it at Las Vegas in my younger days. My advantage over the house started at the very first hand after shuffle. When I released the theory in a 1989 paper in SIAM Journal of Computing, blackjack was only mentioned as one of the three applications. Clever MIT people saw through the disguise by the serious paper title “Dynamic programming by exchangeability.” 报告2: Computing by symmetry The popular 2008 movie "21" was based on the story of the MIT Blackjack Team, which won $M’s in Las Vegas, Atlantic City, the Bahamas, St. Martin, Aruba, Puerto Rico, Europe, ... in the early 1990s. The Team was formed after my years at MIT (1974-76). They called me up before their magnificent tour and tried to invite me to join, before which time I had not heard of this Team. At an age before Internet, the Team managed to track me down on the opposite side of the earth. Why me? 李硕彦 ( Bob Li ) 简介: 1970 年毕业于国立台湾大学，1974 年美国加州大学 Berkeley 数学博士，1974-76 年于 M.I.T. 教授应用数学。1976-79 年于伊利偌大学 Chicago 教授数学、统计学、计算机科学，1979-89 年于贝尔通信实验室研究通信理论、交换系统。1989 年至今任香港中文大学信息工程讲座教授。目前兼任网络编码研究所所长，以及西南交通大学、电子科技大学、哈尔滨工程大学、西安电子科技大学、国立清华大学诸校的名誉教授。同时也是教育部 “创新引智计划” 北邮基地的学术大师，并曾兼任北京大学深圳研究生院特聘教授、北京邮电大学顾问教授。 邀请人: 马啸 教授 李教授是网络编码的创立者之一，李、杨、蔡合著的 Linear Network Coding 获 IEEE 信息理论学会 2005 年度论文奖。台湾工研院 (ITRI) 的 “Metro Switch” 计划中所用的 “Algebraic Switching Fabric” 来自他的 “Algebraic Switching Theory and Broadband Applications” 一书。他 1980 年的 Martingale of Patterns 论文开创了一项研究，可应用于基因工程和其他领域。至今获得32项美国专利。工程的根基主要是数学。李教授长期致力于建立抽象数学与工程之间的新桥梁，应用于无线通信、网络通信、网络安全、信息编码、生物信息学、计算机科学、优化处理、博弈等领域。李教授的个人主页 www.ie.cuhk.edu.hk/bobli 可以链接到 “数学与工程的对话” 系列的讲搞，取材自长年工作的累积。