语种识别算法中GSV计算的定点仿真与实现

基于GSV-SVM的语种识别方法是目前最为流行的语种识别方法之一,其采用基于通用背景模型GMM-UBM的GSV作为声学模型,支持向量机SVM作为区分模型。大量仿真测试结果表明,GSV在整个系统中占的运算量为80%左右,是算法硬件实现的瓶颈。鉴于此,对基于GSV的硬件实现方法进行了研究,提出了一种快速GSV定点计算方法,其采用addlog运算简化对数似然函数的计算,完成了语种识别的高效定点实现。实验结果表明,该定点方法的识别率与浮点识别基本一致,满足应用要求。

基于子空间映射和得分规整的GSV-SVM方言识别

为了提高语音识别中方言识别由于差异性小混淆度高造成识别率低的问题,针对汉语普通话、青海方言和藏语安多方言设计一个基于子空间映射和分数归一化技术的GSV-SVM方言识别系统。利用最大后验概率准则自适应生成KL核的GSV,对GSV进行低维子空间映射;再利用映射后的空间训练多SVM模型进行得分域规整与识别。实验结果表明,采用该系统可以有效对混淆度高的方言进行识别。

Dynamic tracking and mobility analysis of single GLUT4 storage vesicle in live 3T3-L1 cells

Glucose transporter 4 (GLUT4) is responsible for insulin-stimulated glucose transporting into the insulin-sensitive fat and muscle cells. The dynamics of GLUT4 storage vesicles (GSVs) remains to be explored and it is unclear how GSVs are arranged based on their mobility. We examined this issue in 3T3-L1 cells via investigating the three-dimensional mobility of single GSV labeled with EGFP-fused GLUT4. A thin layer of cytosol right adjacent to the plasma membrane was illuminated and successively imaged at 5 Hz under a total internal reflection fluorescence microscope with a penetration depth of 136 nm. Employing single particle tracking, the three-dimensional subpixel displacement of single GSV was tracked at a spatial precision of 22 nm. Both the mean square displacement and the diffusion coefficient were calculated for each vesicle. Tracking results revealed that vesicles moved as if restricted within a cage that has a mean radius of 160 nm, suggesting the presence of some intracellular tethering matrix. By constructing the histogram of the diffusion coefficients of GSVs, we observed a smooth distribution instead of the existence of distinct groups. The result indicates that GSVs are dynamically retained in a continuous and wide range of mobility rather than into separate classes.

Robust PolInSAR optimal interferogram estimation method based on generalized scattering vector

For the polarimetric synthetic aperture radar interferometry(PolInSAR) processing, it is necessary to coregister all the images, including the coregistration of polarimetric SAR images and the coregistration of interferometric SAR images. Otherwise,the performance of the estimated optimal interferograms will be deteriorated. A generalized scattering vector(GSV) model is proposed to execute the PolInSAR optimal interferograms estimation.The generalized scattering vector is constructed by the Pauli scattering vectors of the processing pixel and the surrounding pixels.Even though there are coregistration errors, all the polarimetric information of the current processing pixel is entirely included in the generalized scattering vector. Therefore, the GSV-based method can automatically recover the optimal scattering mechanisms of the processing pixel with coregistration errors either in interferoemetric channels or polarimetric channels. Theoretical analysis and processing results of simulated Pol SARPro data and real PALSAR data validate the effectiveness and correctness of the proposed method.

Characterization of GLUT4-containing vesicles in 3T3-L1 adipocytes by total internal reflection fluorescence microscopy

Insulin-responsive GLUT4(glucose transporter 4) translocation plays a major role in regulating glucose uptake in adipose tissue and muscle.Whether or not there is a specialized secretory GSV(GLUT4 storage vesicle) pool,and more importantly how GSVs are translocated to the PM(plasma membrane) under insulin stimulation is still under debate.In the present study,we systematically analyzed the dynamics of a large number of single GLUT4-containing vesicles in 3T3-L1 adipocytes by TIRFM(total internal reflection fluorescence microscopy).We found that GLUT4-containing vesicles can be classified into three groups according to their mobility,namely vertical,stable,and lateral GLUT4-containing vesicles.Among these groups,vertical GLUT4-containing vesicles exclude transferrin receptors and move towards the PM specifically in response to insulin stimulation,while stable and lateral GLUT4-containing vesicles contain transferrin receptors and show no insulin responsiveness.These data demonstrate that vertical GLUT4-containing vesicles correspond to specialized secretory GSVs,which approach the PM directly and bypass the constitutive recycling pathway.

Endoscopic vein harvest in elective off-pump coronary artery bypass grafting

While traditional open vein harvest was related to postoperative wound complications, endoscopic vein harvest was developed to minimize the morbidity in the greater saphenous vein harvest procedure. In this study, these two procedures were compared for postoperative wound healing and long-term graft patency. We reviewed all consecutive patients undergoing elective off-pump coronary artery bypass grafting from January 2004 to December 2005 and collected data regarding wound complications and coronary events. Wound complications included dehiscence, excessive discharge, edema, altered sensation, cellulitis, hema-toma, pain scale, and superficial and deep wound infection. Coronary events were defined as diagnosis of myocardial infarction during the first year's follow-up. A total of 392 patients were included in our series, among whom 44 were excluded from the study due to emergent operation, preoperative intra-aortic balloon pump support, or the greater saphenous vein varicose characteristic, 78 belonged to open vein harvest group, and 270 to endoscopic vein harvest group. Wound complications were significantly less in the endoscopic group (5.2%) compared to the open group (19.2%) (P=0.0002). There was no significant difference on preopera-tive risk factors, total operative time, or hospitalization days. During one-year follow-up, both the early and late graft patency rates were similar between the two groups. Endoscopic vein harvest is safe and effective, which carries less risk for wound complica-tions and is associated with better satisfaction and cosmetic result than the traditional greater saphenous vein harvest procedure. The endoscopic vein harvest also demonstrates a great long-term patency.