基于语音谐波结构的鲁棒特征参数及其在说话人识别中的应用

通过对纯净语音及含噪语音短时谱的分析比较,提出了一种基于基音频率及其谐波结构的新的语音特征参数。实验表明,与传统的倒谱特征相比,新特征对加性白噪声相对较不敏感,在闭集文本无关说话人识别中,新特征可以在加性白高斯噪声环境下提高系统的说话人识别率。     

基于幅度压缩滤波的清浊音分类及基音估计

该文针对传统算法在实环境(不同噪声类型和信噪比)下容易发生清浊误判和基音估计错误问题,提出一种基于幅度压缩基音估计滤波(PEFAC)的清浊音分类及基音估计方法。首先,通过PEFAC削弱语音的低频噪声,提取出基音谐波;然后,采用基于对称平均幅度和函数的脉冲序列加权算法(SIM)确定谐波数目;最后,利用动态规划估计出基音,用基于3元素特征矢量的高斯混合模型对清浊音进行分类。仿真结果表明,在实环境下,所提方法能有效抑制清浊误判及基音估计错误现象的发生,性能优于传统方法。     

改进汉语数码语音识别中的语音特征提取性能

汉语数据码语音识别中存在三种与语音特征提取性能有关的语音混淆。     

The role of pitch in the discrimination of voice quality

Pitch is an important attribute of a musical sound. With it the melody of a song is established. With it the beauty of a voice is showcased. But how does pitch affect the perception of voice? Is it used to help to distinguish among voices or does it merely exist in the background, affecting the fine details of a voice but not radically altering the voice? The purpose of this paper is to review some of the evidence on the role of pitch in the perception of voice quality; specifically for the discrimination of one voice quality from another. The objective of the discussion is to understand how pitch affects our perception of voice quality and its importance to the perception of musical sound.     

Dissimilarity and the Classification of Female Singing Voices: A Preliminary Study

Traditionally, timbre has been defined as that perceptual attribute that differentiates two sounds when pitch and loudness are equal and thus is a measure of dissimilarity. By such a definition, each voice possesses a set of timbres, and the identity of any voice or voice category across different pitch-loudness-vowel combinations must be due to an abstraction of the pattern of timbre transformation. Using stimuli produced across the singing range by singers from different voice categories, this study sought to examine how timbre and pitch interact in the perception of dissimilarity. This study also investigated whether listener experience affects the perception of timbre as a function of pitch. The resulting multidimensional scaling (MDS) representations showed that for all stimuli and listeners, dimension 1 correlated with pitch, whereas dimension 2 correlated with spectral centroid and separated vocal stimuli into the categories mezzo-soprano and soprano. Dimension 3 appeared highly idiosyncratic depending on the nature of the stimuli and on the experience of the listener. Inexperienced listeners appeared to rely more heavily on pitch in making dissimilarity judgments than did experienced listeners. The resulting MDS representations of dissimilarity across pitch provide a glimpse of the timbre transformation of voice categories across pitch.     

以褐煤为原料制备水溶性沥青

以褐煤为原料、亚硫酸铵为磺化试剂,制备水溶性沥青.实验探索了反应时间、反应温度、亚硫酸铵用量、甲醛用量、氨水浓度对水溶性沥青产率及其性能的影响.结果表明：3g原料沥青、1g亚硫酸铵、1mL甲醛、30mL 40％氨水,反应时间1.5h,反应温度75℃条件下制备的沥青水溶物为59％.     

Effects of Increasing Time Delays on Pitch-Matching Accuracy in Trained Singers and Untrained Individuals

Trained singers (TS) generally demonstrate accurate pitch matching, but this ability varies within the general population. Pitch-matching accuracy, given increasing silence intervals of 5, 15, and 25 seconds between target tones and vocal matches, was investigated in TS and untrained individuals. A relationship between pitch discrimination and pitch matching was also examined. Thirty-two females (20–30 years) were grouped based on individual vocal training and performance in an immediate pitch-matching task. Participants matched target pitches following time delays, and completed a pitch discrimination task, which required the classification of two tones as same or different. TS and untrained accurate participants performed comparably on all pitch-matching tasks, while untrained inaccurate participants performed significantly less accurately than the other two groups. Performances declined across groups as intervals of silence increased, suggesting degradation of pitch matching as pitch memory was taxed. A significant relationship between pitch discrimination and pitch matching was revealed across participants.     

基于火炮后座模拟试验台的俯仰角度控制

本文介绍了后坐模拟试验台俯仰角度控制系统的设计,给出了具体方案设计和软件设计过程。通过控制步进电机经由变速器实现预定俯仰角度控制,连接在俯仰机构上的光电编码器实现俯仰角度的精确检测,据此实现角度俯仰的精确控制。实验结果显示该方案准确、快速、精度高,完全符合系统要求,具有非常大的实用价值。     

提升小波加权自相关函数的基音检测算法*

随着计算机技术的发展,语音信号处理作为人机交互的重要渠道,其在复杂噪声环境下的特征值检测算法直接关系到计算机的运算效率。基音周期是语音特征值提取的重要参数之一。针对传统基音检测算法在噪声环境下检测精度低的问题,提出了一种基于自适应提升小波变换加权线性预测误差自相关函数的基音检测算法。该方法用多级提升小波近似系数加权求和的方法来弥补自相关函数随着时间延迟量的增加幅值衰减的缺陷;用线性预测误差自相关函数的方法来抑制共振峰的干扰,然后将两种方法结合来突出基音周期处的峰值。实验结果表明,与传统的自相关函数法和小波加权法相比,该方法能有效减弱共振峰的影响,突出基音周期处的峰值,提高基音周期检测精度,鲁棒性更好。     

Synthesis and characterization of non-symmetrical liquid crystals containing a cholesteryl ester moiety

In this paper,a series of chiral non-symmetrical liquid crystals(nBA-chol)consisting of a cholesteryl ester moiety as chiral entity and a biphenyl aromatic core with different terminal alkyl chain has been synthesized and investigated for their liquid crystalline properties.Effects of numbers of methylene units in the terminal alkyl chain on the phase transition temperatures and on the temperature-dependent pitch lengths of the chiral liquid crystals have been studied.The long terminal alkyl chain tends ...