Browsing by Author "Cheng, Minquan"

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Codes with the identifiable parent property for multimedia fingerprinting
(2017-04-01)
Cheng, Minquan
;
Fu, Hung-Lin
;
Jiang, Jing
;
Lo, Yuan-Hsun
;
Miao, Ying
Let be a q-ary code of length n and size M, and be the set of ith coordinates of . The descendant code of a sub-code is defined to be . In this paper, we introduce a multimedia analogue of codes with the identifiable parent property (IPP), called multimedia IPP codes or t-MIPPC(n, M, q), so that given the descendant code of any sub-code of a multimedia t-IPP code , one can always identify, as IPP codes do in the generic digital scenario, at least one codeword in . We first derive a general upper bound on the size M of a multimedia t-IPP code, and then investigate multimedia 3-IPP codes in more detail. We characterize a multimedia 3-IPP code of length 2 in terms of a bipartite graph and a generalized packing, respectively. By means of these combinatorial characterizations, we further derive a tight upper bound on the size of a multimedia 3-IPP code of length 2, and construct several infinite families of (asymptotically) optimal multimedia 3-IPP codes of length 2.
New bounds on (2)over-bar-separable codes of length 2
(2015-01-01)
Cheng, Minquan
;
Fu, Hung-Lin
;
Jiang, Jing
;
Lo, Yuan-Hsun
;
Miao, Ying
Let be a code of length over an alphabet of letters. The descendant code of is defined to be the set of words such that for all . is a -separable code if for any two distinct such that , , we always have . The study of separable codes is motivated by questions about multimedia fingerprinting for protecting copyrighted multimedia data. Let be the maximal possible size of such a separable code. In this paper, we provide an improved upper bound for by a graph theoretical approach, and a new lower bound for by deleting suitable points and lines from a projective plane, which coincides with the improved upper bound in some places. This corresponds to the bounds of maximum size of bipartite graphs with girth and a construction of such maximal bipartite graphs.