A Chinese sign language recognition system based on SOFM/SRN/HMM
In sign language recognition (SLR), the major challenges now are developing methods that solve signer-independent continuous sign problems. In this paper, SOFM/HMM is first presented for modeling signer-independent isolated signs. The proposed method uses the self-organizing feature maps (SOFM) as different signers' feature extractor for continuous hidden Markov models (HMM) so as to transform input signs into significant and low-dimensional representations that can be well modeled by the emission probabilities of HMM. Based on these isolated sign models, a SOFM/SRN/HMM model is then proposed for signer-independent continuous SLR. This model applies the improved simple recurrent network (SRN) to segment continuous sign language in terms of transformed SOFM representations, and the outputs of SRN are taken as the HMM states in which the lattice Viterbi algorithm is employed to search the best matched word sequence. Experimental results demonstrate that the proposed system has better performance compared with conventional HMM system and obtains a word recognition rate of 82.9% over a 5113-sign vocabulary and an accuracy of 86.3% for signer-independent continuous SLR.

title: A SRN/HMM system for signer-independent continuous sign language recognition
abstract: Sign language recognition is to provide an efficient and accurate mechanism to transcribe sign language into text or speech. State-of-the-art sign language recognition should be able to solve the signer-independent continuous problem for practical applications. A divide-and-conquer approach, which takes the problem of continuous Chinese Sign Language (CSL) recognition as subproblems of isolated CSL recognition, is presented for signer-independent continuous CSL recognition. In the proposed approach, the improved simple recurrent network (SRN) is used to segment the continuous CSL. The outputs of SRN are regarded as the states of hidden Markov models (HMM) in which the Lattice Viterbi algorithm is employed for searching for the best word sequence. Experimental results show that the SRN/HMM approach has a better performance than the standard HMM.

title: On zero-sum subsequences of restricted size II
abstract: Let G be a finite abelian group of exponent m, and k a positive integer. Let s"k"m(G) be the smallest integer t such that every sequence of t elements in G contains a zero-sum subsequence of length km. In this paper, we determine s"k"m(G) for some special groups G and study the number of zero-sum subsequences of length m.

title: Addition Theorems and Group Rings
abstract: We establish several addition theorems on finite abelian groups by employing a group ring as a useful tool. Among several results the following is proved. Letpbe a prime, and letG=Zpe1???Zpenwith 1?e1???en. Putw=(1/(pen?1))×?ni=1(pei?1). Then, for anyt?(pen?1)logw+pen?2 linear basesB1, ?,BtofGtheir union (with repetitions) ?ti=1Biforms an additive basis ofG.

title: On the number of zero sum subsequences
abstract: For a sequence S of elements from an additive abelian group G, let f(S) denote the number of subsequences of S the sum of whose terms is zero. In this paper we characterize all sequences S in G with f(S) > 2 |S| 2 , where |S| denotes the number of terms of S.

title: Zero-sum problems and coverings by proper cosets
abstract: Let G be a finite Abelian group and D(G) its Davenport constant, which is defined as the maximal length of a minimal zero-sum sequence in G. We show that various problems on zero-sum sequences in G may be interpreted as certain covering problems. Using this approach we study the Davenport constant of groups of the form (Z/nZ)r, with n ≥ 2 and r ∈ N. For elementary p-groups G, we derive a result on the structure of minimal zero-sum sequences S having maximal length |S| = D(G).

title: An addition theorem for finite cyclic groups
abstract: The following theorem is proved. Let 2 ⩽ k ⩽ [ n 4 ] + 1 , and let S be a sequence of 2n − k elements in Zn. Suppose that S does not contain any n-subsequence with 0-sum. Then, one can rearrange S to the type a, …,a, b, …, b, c1, …, c2n-k-u-v, where u ⩾ n − 2k + 3, v ⩾ n − 2k + 3, u + v ⩾ 2n − 2k + 2 and a − b generates Zn.