学术报告
编码密码学术活动月系列活动六-汪馨（苏州大学） 方伟军（清华大学深圳国际研究生院）
题目: Improved Lower Bounds for Constant-Composition Codes
报告人：汪馨 博士 （苏州大学）
报告时间：2020年10月28日 上午8:30-9:30
摘要: There is a close relationship between Sidon set and error correcting code.
In this talk, we give a new construction for constant-composition codes with techniques in additive number theory. It turns out that when $d=4$ and $5$ our bound improves the one by Ding (2008) substantially. Moreover, we provide a new connection between constant-composition codes and linear block codes with certain properties. It turns out that when $d/geq 6$ our new lower bound improves the previous one by Ding (2008) substantially.
题目: Improved Bounds and Optimal Constructions of Locally Repairable Codes
报告人：方伟军 博士 （清华大学深圳国际研究生院）
报告时间：2020年10月28日 上午9:30-10:30
摘要: In this talk, we first of all derive an improved and general upper bound on the code length of Singleton-optimal LRCs with minimum distance d=5, 6. Secondly, we obtain a complete characterization for Singleton-optimal LRCs with r=2 and d=6. And then we construct three new Singleton-optimal LRCs with large code length via some special structures of projective plane. In the end, we employ the well-known line-point incidence matrix and Johnson bounds for constant weight codes to derive tighter upper bounds on the code length, and the maximal value of the length of Singleton-optimal LRCs for some specific q are also determined.
腾讯号：202 387 623
联系人：张俊
主办单位：首都师范大学77779193永利官网、首都师范大学交叉科学研究院
