Graph Pattern Matching (GPM) plays a significant role in many real applications, where given a graph pattern Q and a data graph G, computing the set M(Q, G) of matching subgraphs of Q in G. However, many applications like the experts recommendation in social networks, often need to find Top-K matches of a designated node v0, rather than the entire set M(Q, G). Moreover, the existing GPM method for matching the designated node v0does not consider the multiple constraints of the attributes associated with each vertex and each edge which commonly exist in real applications, like the constraints of social contexts for the experts recommendation in contextual social. In this paper, we first propose the Multi-Constrained Top-K Graph Pattern Matching problem (MC-Top-K-GPM), which involves the NP-Complete Multiple Constrained GPM problem. To address the efficiency and effectiveness issues of MC-Top-K-GPM in large-scale social graphs, we propose a novel index, called HB-Tree, which indexes the label and degree of nodes in G and can get candidates of v0efficiently. Furthermore, we develop a Multi-Constrained Top-K GPM method, called MTK, which can identify Top-K matches of v0effectively and efficiently. Using real-life data, we experimentally verify that MTK outperforms the existing GPM algorithms in both efficiency and effectiveness in solving the MC-TOP-K GPM problem.

We present a novel method that performs spatio temporal editing of 3-D multiparty interaction scenes for free-viewpoint browsing, from separately captured 3-D video data. The main idea is to first propose the augmented motion history volume (aMHV) for individual motion representation. Then, by modeling the correlations between different aMHVs, we can define a multiparty interaction dictionary, describing the spatiotemporal constraints for different types of multi-party interaction events. Finally, a constraint satisfaction and a global optimization method synthesize natural and continuous 3-D multiparty interaction scenes. Evaluations with real data demonstrate the effectiveness of our method.

In this paper we present a novel method that performs spatiotemporal editing of 3D multi-party interaction scenes for free-viewpoint browsing, from separately captured data. The main idea is to first propose the augmented Motion History Volume (aMHV) for motion representation. Then by modeling the correlations between different aMHVs we can define a multi-party interaction dictionary, describing the spatiotemporal constraints for different types of multiparty interaction events. Finally, constraint satisfaction and global optimization methods are proposed to synthesize natural and continuous multi-party interaction scenes. Experiments with real data illustrate the effectiveness of our method.

A novel quality of service (QoS) scheduling mechanism suitable for transporting variable bit rate video in the upstream direction over a DOCSIS (data over cable system interface specification)-compliant cable network is presented. It is shown, via simulation using real life video traces, that the proposed scheduling service provides significant improvements as compared to the existing DOCSIS QoS scheduling services, with regard to bandwidth utilization and latency distribution. The proposed scheduling service is also applicable to transport integrated services over the Internet and can be utilized by other emerging multimedia applications, where data are bursty in nature and variable in bit rate.

The effect of clipping-induced impulse noise in externally modulated multichannel AM/M-QAM video transmission systems is investigated. It is shown that the bit-error-rate of the M-QAM signals in the symmetric double-clipping events is, to the first order approximation, twice the single clipping events under the same conditions. The results are in good agreement with the experimental data for both 1319-nm and 1550-nm externally modulated laser transmitter-based systems.

Performance analysis for a hybrid subcarrier-multiplexed (SCM) AM/QAM transmission over an optical fiber is presented. It is shown that the bit-error-rate (BER) of M-ary QAM in such hybrid systems can be significantly affected due to occasional laser "clipping" of the SCM signal. Here we analytically determine the asymptotic distribution of the clipping noise by modeling it as a Poisson impulse train. The BER of M-ary QAM is then evaluated in terms of optical modulation indices of M-ary QAM and AM signals which in turn specify signal-to-noise ratio (SNR), impulsive index (clipping index) of the clipping noise, and power ratio of the Gaussian noise to the clipping noise. Numerical examples are given and compared with experimental data with reasonably good agreement for small SNR's. The results have application for estimating the BER's of digital signals for SCM analog/digital transmission over an optical fiber and for employing appropriate error correction codes and/or optimum receiver design for such environments.>

A simulation study of the statistical properties of two eigenvector-based methods for angle-of-arrival estimation is presented. The two methods investigated are the multiple signal classification (MUSIC) method developed by R.O. Schmidt (1986) and the eigenvector rotation (ER) method developed by G. Vezzosi (1982) and further pursued by Farrier and Jeffries. The results demonstrate (a) that for large sample size both MUSIC and ER estimates approach the normal distribution with zero mean, (b) that the ER method generally performs better than MUSIC with respect to bias and variance at low signal-to-noise ratios and/or small sample size, and (c) that ER (or augmented ER, where pertinent) is more robust than MUSIC with regard to sensor position errors and source correlations.>

The forward-backward averaging (FBAV) method known for resolving coherent arriving signals is utilized to overcome the deleterious effect of scatter on superresolution spectral estimators. The method is here applied to an aircraft mounted array which sees direct and scattered signals, the latter coming from the aircraft body. The idea is to decouple the scattered signals from the directly arriving signals with which they are correlated. The effectiveness of this method in dealing with scatter is demonstrated by simulations.>