Tran Dang Hien

Tran Dang Hien, Do Van Tuan, Pham Van At

Nonnegative matrix factorization (NMF) is an emerging technique with a wide spectrum of potential applications in data analysis. Mathematically, NMF can be formulated as a minimization problem with nonnegative constraints. This problem is currently attracting much attention from researchers for theoretical reasons and for potential applications. Currently, the most popular approach to solve NMF is the multiplicative update algorithm proposed by D.D. Lee and H.S. Seung. In this paper, we propose an additive update algorithm, that has faster computational speed than the algorithm of D.D. Lee and H.S. Seung.

Do Van Tuan, Tran Dang Hien, Pham Van At

This paper presents a new scheme for hiding a secret message in binary images. Given m*n cover image block, the new scheme can conceal as many as log(m*n +1) bits of data in block, by changing at most one bit in the block. The hiding ability of the new scheme is the same as Chang et al.'s scheme and higher than Tseng et al.'s scheme. Additionally, the security of the new scheme is higher than the two above schemes.