Weizhong Liu

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In this paper we construct a class of LDPC codes with girth 10 based on 2-D lattices. The parity check matrix is an incident matrix of lines and points in the lattices. By selection of slope sets, general triangles and quadrangles are removed in the lattices which leads to the corresponding codes have girth no less than 10. The codes are regular, whose(More)
The emergency of HTML 5 enhances the capabilities of real time interaction on web and innovates the development of real-time collaboration in Web browser. This paper proposes a joint framework for HTML 5 specification and a double-model architecture for real-time web collaboration development. A Simple Collaboration Modeling Language is developed to(More)
A technique for restoring the blurred image resulted from defocusing of the lens is proposed in this paper, which is based on fractional Fourier transform (FRFT). The FRFT, as a powerful tool for the analysis of time-varying signals, is closely connected with the optical imaging system. FRFT also can describe optical imaging process just like Fresnel(More)
E-learning concerns an education system based on computer and network technology and has become one of the most potential e-commerce business. As one kind of e-learning system, video-on-demand (VOD) learning system can offer learners additional approach to absorb new knowledge without the restriction of time and place. Many researches have proved that(More)
In the paper, a new approximating subdivision scheme is presented for quadrilateral nets with 4-valence topology which generates the limit surface of C/sup 1/ in the limit at the regular face and quasi-tangent plane continuous at the irregular region. The main advantage of the scheme comparing with other algorithms is limit surfaces generated by the scheme(More)
A fast motion estimation algorithm based on global sampling is presented in this paper. It runs global sampling search with multiple precision in the search window first and then runs 2-step fine search with multiple patterns, which significantly avoids the search falling into the local-minimum point. Making use of the temporal and spatial features in video(More)