基于谱减法的语音增强算法研究

在通信质量日益提升的现代通信时代,对语音信号的处理研究仍然是一个基本而复杂的课题。在语音增强技术中产生了众多处理方法。笔者在谱减法的理论研究基础上,验证了谱减法对语音信号的语音增强在技术上有明显的效果。但是在谱减法中的＂音乐噪声＂处理上还是不如人意,仍然会出现节奏性的噪声,这也是日后不断需要研究的方向,以实现语音增强技术的理想化。     

Adjusting athletes' body mass index to better reflect adiposity in epidemiological research

Abstract

The aim of the present study was to identify when body mass index (BMI) is unlikely to be a valid measure of adiposity in athletic populations and to propose a simple adjustment that will allow the BMI of athletes to reflect the adiposity normally associated with non-athletic populations. Using data from three previously published studies containing 236 athletes from seven sports and 293 age-matched controls, the association between adiposity (sum of 4 skinfold thicknesses, in millimetres) and BMI was explored using correlation, linear regression, and analysis of covariance (ANCOVA). As anticipated, there were strong positive correlations (r = 0.83 for both men and women) and slope parameters between adiposity and BMI in age-matched controls from Study 1 (all P < 0.001). The standard of sport participation reduced these associations. Of the correlations and linear-regression slope parameters between adiposity and BMI in the sports from Studies 2 and 3, although still positive in most groups, less than half of the correlations and slope parameters were statistically significant. When data from the three studies were combined, the ANCOVA identified that the BMI slope parameter of controls (5.81 mm · (kg · m^?2)^?1) was greater than the BMI slope parameter for sports (2.62 mm · (kg · m^?2)^?1) and middle-distance runners (0.94 mm · (kg · m^?2)^?1) (P < 0.001). Based on these contrasting associations, we calculated how the BMI of athletes can be adjusted to reflect the same adiposity associated with age-matched controls. This simple adjustment allows the BMI of athletes and non-athletes to be used with greater confidence when investigating the effect of BMI as a risk factor in epidemiological research.     

基于自适应参数的多窗谱谱减法算法改进

当今人工智能发展迅速,语音识别成为人机交互的重要方式。为提高语音识别准确度,在分析语音信号前去除语音信号噪声干扰并提高语音信号能量尤为重要。在实际应用中,不同语音信号包含不同的噪声。针对不同的语音噪声,在传统谱减法基础上,通过判断算法窗函数,根据不同的噪声能量改变多窗谱减法的过减因子参数,以增强算法自适应能力。仿真结果表明,在低信噪比情况下,通过改变过减因子值,可取得一个最优过减因子值以改进谱减法下的音乐噪声和失真度。自适应多窗谱减法改进后与基本谱减法相比,信噪比提高了 29%;与多窗谱减法相比,信噪比提高了 16%。该自适应多窗谱减法可适应不同噪声环境下的语音信号,增强语音信号中的关键信息并减少噪声干扰。     

单叶矩阵函数的一个充要条件(英文)

本文研究开单位圆盘D={|z|<1}内的n×n阶复矩阵函数F(z)=(f_(i k)(z))1≤i,k≤n,得到了矩阵函数F(z)在D内单叶的一个充分必要条件。     

Numerical Analysis of the Stability of Embankment Slope Reinforced with Piles

The effects of stabilizing piles on the stability of an embankment slope are analyzed by numerical simulation. The shear strength reduction method is used for the analysis, and the soil - pile interaction is simulated with zero-thickness elasto-plastic interface elements. Effects of pile spacing and pile position on the safety factor of slope and the behavior of piles under these conditions are given. The numerical analysis indicates that the positions of the pile have significant influence on the stability of the slope, and the pile needs to be installed in the middle of the slope for maximum safety factors. In the end, the soil arching effect closely associated with the space between stabilizing piles is analyzed. The results are helpful for design and construction of stabilizing piles.     

基于虚拟仪器的傅立叶变换光谱分析实验系统

介绍了利用LabVIEW虚拟仪器技术改造后的傅立叶变换光谱分析实验系统,与采用VB语言开发的实验系统相比具有程序设计工作量小、运行可靠、便于升级、测量精度高的特点,并且可以同时作为展示虚拟仪器技术应用实例的教学平台。     

高光谱遥感影像中光谱向量编码方法的研究

Taking into account the demands of hyperspectral remote sensing (RS) image retrieval and processing, some encoding methods of spectral vector including direct encoding, feature-based encoding and tree-based encoding methods are proposed and compared. In direct encoding, based on the analysis of binary encoding and quad-value encoding, decimal encoding is proposed. It is proved that quad-value encoding and decimal encoding are suitable to fast processing and retrieval. In absorption feature-based encoding method, five common metrics are compared. Because locations of reflection/absorption features are sensitive to noise, this method is not very effective in retrieval. In tree-based encoding methods, bitree, quadtree, octree and hextree are proposed and discussed. It is proved that 2-level octree and 2-level hextree are more effective than bitree and quadtree. Finally, quad-value encoding, decimal encoding, 2-level octree and 2-level hextree are proposed in spectral vectors encoding, similarity measure and hyperspectral RS image retrieval.     

图的移接变换与谱半径大小的关系

利用主特征向量法,给出了主特征分量从优的边移接变换和平衡枝变换两个定义,总结了一般图的移接变换与其谱半径大小关系的相关结论,并应用于特殊图,得到了特殊图上的移接变换与谱半径大小关系的一个结论.     

Korteweg-de-Vries方程有限谱数值格式

以kdV方程为模型,利用有限谱方法构造数值计算格式,检验有限谱法计算含有色散项的非线性方程的精度,并对孤立波的演化及孤立波的碰撞进行了数值模拟,结果说明有限谱数值格式能较准确地模拟孤立波的行为.同时,把有限谱数值格式的计算结果同解析解进行对比,结果表明有限谱法具有较高的精度.     

路堑岩质边坡稳定性级别研究

路堑岩质边坡具有规模大、数量多、参数获取困难、治理难度大等特点,历来是线路工程中的研究热点.为了解决路堑岩质边坡的稳定评价问题,建立边坡稳定性的模糊综合评价体系,可供同类工程借鉴.根据路堑岩质边坡的特点,以系统全面性、简明科学性、相对独立性及灵活可操作性为原则,选取合理的边坡稳定性评价指标,建立边坡稳定性的模糊综合评价体系,运用层次分析法确定评价指标的权重,建立了路堑岩质边坡的稳定性分级模型.以某国道辅线K57+411～K57+536段边坡为例,运用该模型对其稳定性级别进行了模糊综合评判分级,其结果为不稳定,与规范法的评价结果一致,表明该方法是合理实用的.