变速变桨距风力发电系统的逆系统控制器性能评估

基于风机模拟实验平台,本文验证了作者提出的用于风力发电系统浆距角控制的逆系统控制器的性能。由于系统动态呈典型的非仿射非线性特性。该控制器根据逆系统控制理性的相关方法,直接使用风力机制造商提供的数据对呈非线性的风机特性进行建模,通过多时间尺度方法将模型转化为具有非仿射型非线性特性的一阶动态系统,然后使用逆系统与之级联,使级联系统呈“伪线性”。同时,为消除参数不确定性,风速检测误差和发电机转矩扰动对系统输出功率的影响经制器中额外加入了鲁棒补偿器。风机模拟平台上的实验表明,相比传统PI控制器,ISC控制器能使系统输出功率更加稳定,并能降低桨距角的调节频率和减小其调节幅度,有利于降低系统机械疲劳。此外还具有结果简单,参数易整定的特点,易于在嵌入式控制器中实现。     

Two kings of pitch predictors in speech compressing coding

This paper studies two kinds of methods for pitch predictor in speech compressing coding, i.e., open-loop and closed-loop structures. Some of simplified approaches for solving pitch predictor equation are suggested, and the performances are compared under several conditions. The computer simulation results are shown.     

Vocal fundamental frequency measures as a reflection of tumor response to chemotherapy in patients with advanced laryngeal cancer

The fundamental frequency (F₀) characteristics of 19 male patients with advanced laryngeal cancer, treated with cisplatin-based chemotherapy as part of a Larynx Preservation Protocol (LPP), were measured before each of three cycles of chemotherapy received before definitive radiotherapy (RT). In these select patients, for whom chemotherapy resulted in 50% decrease in the tumor bulk, it was found that mean F₀ was essentially unaffected by the disease and did not change over the course of chemotherapy, although the cycle of their treatment could be differentiated by both speaking F₀ variability (pitch sigma) and F₀ perturbation (fitter). Although these measures failed to distinguish between those patients showing a complete response (CR) (no measurable disease) versus a partial (PR) (residual) tumor response at the primary disease site, the significant changes observed in both groups indicate that frequency variation measures could prove valuable in the documentation of tumor response to nonsurgical therapeutic intervention if the voice is directly affected. Additional assessment of 15 age- and disease-matched patients who showed minimal or no primary response to the chemotherapy showed no significant change in any of the frequency measures after one chemotherapy cycle, suggesting that vocal improvement seen in the successful chemotherapy patients was not due to postbiopsy healing or other systemic influence unassociated with tumor reduction.     

螺距对螺旋慢波系统色散和耦合阻抗的影响

螺距是慢波系统的一个重要参数,直接影响螺旋慢波系统的色散特性和耦合阻抗.严格求解螺距对慢波系统色散和耦合阻抗的影响是不方便的,而通过计算机模拟可以方便快速地研究螺距对慢波系统色散和耦合阻抗的影响.模拟结果表明,对于工程项目当螺距变化小于4%时,螺距对色散和耦合阻抗的影响是很小的.     

Dissimilarity and the Classification of Male Singing Voices

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 ability to identify any voice or voice category across different pitch-loudness-vowel combinations must be due to an ability to "link" these timbres by abstracting the "timbre transformation," the manner in which timbre subtly changes across pitch and loudness for a specific voice or voice category. 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 in male singing voices. This study also investigated whether or not 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, while dimension 2 correlated with spectral centroid and separated vocal stimuli into the categories baritone and tenor. 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.     

基于小波变换的清浊音分类及基音周期检测算法

该文提出了一种基于小波变换的鲁棒性基音周期检测方法。检测前在小波域上用Teager能量算子对语音信号进行清浊音判决,对浊音段采用空域相关函数提取基音周期。实验表明,与传统的小波变换算法和自相关法相比,该方法鲁棒性好,具有更高的准确性。     

低速率WI编码器中4~6bit基音量化算法研究

基音在语音编码中通常采用7bit无失真均匀量化。由于浊音段语音的基音普遍具有缓慢渐变的特点,为了更有效地去除前后帧基音之间存在的相关性,该文基于Eriksson和Kang提出的4bit基音量化算法,针对汉语语音进行研究,实现了一套4~6bit基音量化算法。该算法计算简单,无需码书存储。将此基音量化方案应用于WI模型和WI编码器,主观A/B听力测试结果表明,该方案在高效量化基音的同时保证了合成语音质量几乎没有损失,完全满足低速率WI编码器对量化基音的要求。     

煤精制软沥青庚烷不溶甲苯可溶族结构的光谱分析

以高温煤焦油为原料制备软化点为32℃煤焦油精制软沥青,再以庚烷、甲苯为溶剂超声萃取得庚烷不溶甲苯可溶物。蒸气压渗透法测定庚烷不溶甲苯可溶物平均分子量为349;元素分析与平均分子量结合得平均分子式C26.65H17.62N0.12S0.06O0.51,平均分子中杂原子总数0.68;红外分析结果表明：其杂原子氧以R—O—R,Ar—O—R结构存在,氮以R—NH—R和—N=结构存在,且以—N=为主;采用改进的Brown-Lander模型得其平均结构是六环稠环;紫外分析表明,线性排列为主、面性排列为辅,即庚烷不溶甲苯可溶族的化学结构以渺位缩合为主,迫位缩合为辅。     

一种2.4kbps改进型MBELP编码

该文给出了一种改进的2.4kb/s多带激励线性预测(IMBELP)语音编码算法。与传统的MBELP算法相比,本算法在基音提取和清/浊音判决上采取了一些改进措施,使得合成语音质量有一定的提高。本文详细介绍了改进后的MBELP算法,并将其在基音提取和清/浊音判决的结果与传统的MBELP进行比较。     

语音压缩编码中的两种基音预测器

本文研究了语音压缩编码中基音预测器的两种情形,即开环和闭环结构。提出了一些简化基音预测器求解方法,比较了几种条件下的基音预测器性能。给出了计算机仿真结果。