The role of cognitive cueing in eliciting vocal variability

Variation in duration and frequency during three readings of each of eight sentences by 9 normal and 4 voice-disordered subjects are compared. Instructions to the subjects varied with respect to the amount and type of cognitive cueing presented in the trials, and the sentences were read in random order. Variability in fundamental frequency (F₀) was greater when pitch variation was specifically cued. Also, the portion of the sentence that was cued had greater variability in F₀ than other parts of the sentence. Variation in fundamental frequency was significantly greater in the cued versus uncued sentence trials for the voice-disordered subjects but not for the normal subjects. However, all subjects exhibited significantly greater duration for cued versus uncued readings of the same sentences. Implications for theory and practice are discussed.     

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。     

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。     

Functional demarcation of pitch

A satisfactory solution is yet to be found for the problem of estimating the pitch of speech signals. It is difficult even to evolve objective criteria to evaluate existing algorithms. This is usually done on the basis of complexity of the algorithm, speed of computation, ease of implementation, etc. Even the verification of the results of one particular technique is difficult. This paper presents three functional demarcations of pitch estimation methods (based on the linear model of speech production, analysis of the short-time spectrum and examination of the time domain signal, respectively) as used for speech processing. It is shown that evaluation and comparison of different algorithms becomes consistent and easy within each demarcation. Also, methods falling within each demarcation are shown to be suited for a particular area of speech processing.     

Vocal fold strain and vocal pitch in singing:Radiographic observations of singers and nonsingers

The relationship between vocal fold strain and vocal pitch in singersand nonsingers singing a rising pitch series has been indirectly investigated by means of lateral radiographs. Nonsingers tend to exhibit more strain than singers. To standardize the degree of strain, an index of strain per semitone is proposed. The semitone strain indicates the average amount of strain per 1 semitone of pitch increase or decrease. The index has been shown to be affected by several factors: gender, singing training, singing technique, voice class, age, and status of muscle function. Observations suggest that similar groups of individuals occupy different positions on the stress-strain curve, indicated by their semitone strain values.     

New induced cholesteric micellar liquid crystals. Characterization and pitch determination

Summary New induced cholesteric micellar liquid crystals have been prepared based on potassium laurate and sodium decyl sulfate. The chiral molecule D-glucose was used as dopant. The inverse pitch length is found to be proportional to the added guest. The twist induced by the dopant strongly depends on the nature of the detergent, the principal component of the mesophases. The mesophases are characterized on the basis of the microscopic textures. Deuterium NMR spectra in D₂O shows positive diamagnetic anisotropy for these cholesteric mesophases.

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Neue induzierte cholesterische micellare Flüssigkristalle. Charakterisierung und Ganghöhenbestimmung

Zusammenfassung Es wurden neue induzierte cholesterische micellare Flüssigkristalle basierend auf Kaliumlaurat und Natriumdecylsulfat hergestellt. Als chirales Molekül zur Ausbildung der Phasen wurde D-Glucose benutzt. Es wurde festgestellt, daß die inverse Ganghöhe proportional zur zugesetzten Gastkomponente ist. Die induzierte Schraubung hängt stark von der Natur des Detergens, der Hauptkomponente der Mesophase, ab. Die Mesophasen werden auf der Basis der mikroskopischen Textur charakterisiert. Die Deuterium-NMR-Spektren in D₂O zeigen für diese cholesterischen Mesophasen eine positive diamagnetische Anisotropie.

     

Studies on pore structures and surface functional groups of pitch-based activated carbon fibers

The present study concerns the physical activation and chemical oxidation of pitch-based activated carbon fibers (ACFs) as ways to improve the adsorption properties. The surface oxides of the ACFs studied were determined by Boehm's titration and the pore structures were studied by the BET method with N(2)/77 K adsorption. Also, the adsorption properties of the ACFs were investigated with chromium ion adsorption by different adsorption models. As a result, it was observed that carboxyl groups were largely created after nitric acid treatment on ACFs. The affinity for chromium ions increases with increasing specific surface area, micropore volume, and surface functionalities of ACFs as the activation time increases.     

The Relationship Between Vocal Pitch-Matching Skills and Pitch Discrimination Skills in Untrained Accurate and Inaccurate Singers

Few studies have compared the relationship between pitch discrimination accuracy and the accuracy of fundamental frequency (F(o)) control. This study investigated the relationship between vocal pitch-matching skills, which is one method of testing F(o) control, and pitch discrimination skills in untrained accurate and inaccurate singers, and the effect of timbre on their pitch discrimination accuracy. Data showed that accurate singers had more precise discrimination and pitch-matching abilities compared with their inaccurate counterparts. Pitch discrimination was differentially affected by the timbre (eg, spectral differences) of comparison tones. In addition, results showed a significant relationship between pitch discrimination abilities and pitch-matching accuracy. The results suggest that accurate F(o) control is at least partially dependent on pitch discrimination abilities, which are important for accurate singing.     

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。