基于听觉滤波器波束形成的声源定位

提出基于听觉滤波器波束形成的声源定位方法.利用听觉滤波器把每个通道接收的宽带音频信号分解为若干个窄带频率通道信号,分别估计每个频率通道的"空间谱".根据各个频率通道的信噪比对所有频率通道的"空间谱"进行二值加权累积求"总空间谱",由"总空间谱"可得声源的波达方向.实验结果表明提出的算法是有效的,与经典的算法相比具有更高的精度.     

音乐知识问答(三)

问:什么是“音乐听觉”和“绝对听觉”?答:我们一般把听觉分为物理听觉和音乐听觉。所谓物理听觉,指对声音的“音高”、“音量”、“时值”、“音色”的听辨能力;所谓音乐听觉,俗称“乐感”。是指对音乐作品中各音存在意义的认识,音与音之音微妙关系的感觉,以及在音乐方面的记忆力、模仿能力等。“绝对听觉”(亦作“绝对音高”)是指在没有任何依据(如音叉、乐器等比较音高)的情况下,凭主观听觉即可确定各音的准确高度。具有     

图形万用表在实际测试中的应用

万用表是从事电子制作、检修电子设备的必备工具之一，它是一种可以进行多种项目测量的便携式仪表。现在市场上出售的万用表有两种：一种是指针式万用表，一种是数字式万用表。现在我向大家介绍一种由美国福禄克公司出品的 867GMM图形万用表及其在实际测试中的应用。 867GMM图形式万用表的特点 　　GMM867B有一个独特的在未加电的电路上直接测量元件特性的功能。 GMM867B万用表上方有一个显示屏，上面显示出电路中该元件的伏安特性曲线。其频率的选择分为 2HZ、 20HZ、 200HZ、 18.7KHZ。如此大的频率范围可提供很大的测量能力。 …     

启发式物理演示实验教学模式探索——以声悬浮实验为例

随着演示实验室的升级改造,对现有演示实验教学模式进行探索。以"声悬浮"为选题,设计问题导向、学生主体的教学过程,在完成"声速测量"常规实验的基础上,引导学生自主设计超声悬浮演示实验装置,从固定换能器频率改变噪声反射面形状着手探究颗粒悬浮状态与反射面形状的关系,然后研究不同频率换能器下的颗粒悬浮状态。在此基础上继续探索了在同频双换能器作用下的颗粒悬浮及改变两声波相位差时悬浮颗粒的状态变化,最后进一步研究了不同频率双换能器作用下的颗粒悬浮。通过层层递进的启发方式,激发学生对物理实验的兴趣,使学生创新意识和创新能力得到培养。     

基于扫频法的声速测量实验

介绍了基于扫频法的声速测量实验,借助声卡与虚拟仪器平台,产生扫频声波并分析空气管中的信号频谱,寻找驻波频率并求解声速。实验的设计改变了以往"固定声波频率,调节空气柱长度"的驻波测量模式,系统简单、实验误差小。     

听觉似动条件下对位置距离估计的加工机制

作为盲人的重要感官之一,听觉在其生活中发挥了重要的作用。采用听觉通道下的空间距离估计实验,研究在听觉似动条件下盲生与视力正常学生对空间距离的估计是否存在差异以及相应的影响因素。结果发现,在听觉似动条件下,视力正常学生与盲生对位置距离的估计差异边缘显著,视力正常学生估计的距离更接近真实值;视力正常学生与盲生对位置距离的估计都受刺激时间间隔的影响,刺激时间间隔起调节作用;声音频率对位置距离估计的影响差异不显著。研究支持缺陷说理论。     

声速测量实验装置设计与实现

研制了一种声频率范围内的声速测量系统.该系统主要包括单片机模块、DDS信号发生模块、滤波放大模块及声波导管模块.该装置能控制DDS输出不同频率的正弦波,正弦波信号通过滤波放大电路驱动扬声器发声,声音在声波导管中传播,当改变扬声器与传声器的距离时,合成声波的幅值与相位将发生一系列有规则的变化,并形成驻波,最后由传声器拾取并送示波器显示.可用驻波极值法与相位比较法对声波的波速进行测量,在听觉和视觉上效果明显,可作为普通物理实验装置,也可作为物理演示仪器.     

基于八电极的生物电阻抗分析检测系统设计

精确采集人体生物电阻抗信号,是人体成分分析的重要基础。设计一套测量生物电阻抗系统,利用MSP430主控芯片控制恒流源产生50-300KHz激励电流信号,并通过电极施加于被测人体不同部位,采用八电极多频率阻抗采集法,通过乘法解调对生物三元模型的阻容模型进行测量。实验结果表明,应用不同频率的激励电流信号对同一人体进行测量,不同部位的阻抗值幅值以及偏移相角不同,应选取合适的频率,使测量值与理论值误差达到极小、测量系统精度达到最优。     

儿童“绝对听觉”训练的成功实践

自古以来,“绝对听觉”被认为是一种宝贵的音乐素质或高超的音乐能力,能否对儿童进行形成“绝对听觉”的长期系统培训,是音乐教育的一个难点,本文对“绝对听觉”训练工作的过程及经验教训进行了系统地论述。     

“电阻测量”的两类原理及应用

"电阻的测量"是中学电学实验中的一个基础但极其重要的实验,由于其对学生的双基与能力的检测都非常广泛,而且多数电学实验均可涉入该问题,因而在高考中是一类出现频率极高的问题.本文从电阻的测量原理入手来探讨分析该类问题的方法,以供师生参阅.一、部分电路欧姆定律即伏安法测量电阻     

Auditory Frequency Resolution in Human Infancy

Frequency resolution is a fundamental capacity of the auditory system that underlies the perception of all complex sounds. The development of this capacity has not been well characterized in humans. This investigation used a nonsimultaneous pulsation threshold technique to examine the development of infant frequency resolution. Psychophysical tuning curves were obtained for 3- and 6-month-olds and for adults at either 500, 1,000, or 4,000 Hz. Both the sensation level and the sound pressure level of the stimulus were varied for adults to determine the contribution of stimulus intensity to age differences in frequency resolution. At 500 and 1,000 Hz, 3- and 6-month-olds' tuning curve widths were equivalent to adults'. At 4,000 Hz, the 3-month-olds' tuning curves were broader than those of 6-month-olds and adults, even when absolute sound pressure level was equivalent. The maturation of psychophysical frequency resolution in infants is discussed in terms of the general development of the auditory system and of nonsensory factors that might contribute to age differences in performance.     

Frequency range size and the frequency range constraint in auditory perception by European starlings (Sturnus vulgaris)

We report data bearing on the ability of European starlings to generalize a serial auditory pitch pattern discrimination from one frequency range to another. In earlier research (e.g., Hulse & Cyrix, 1985), European starlings failed to generalize such a discrimination from one 1-octave range of frequencies to another 1-octave range above or below the initial training range. The starlings thus demonstrated a hitherto unknown phenomenon, thefrequency range constraint. In the present research, we first explored the frequency limits over which the range constraint might hold. The constraint was obtained after initial training in both a narrow (1÷2-octave) and a wide (3-octave) training range. The latter range encompasses a substantial portion of the entire frequency range audible to starlings. Therefore, the constraint is independent of the size of the training range. No known principles of stimulus discrimination or generalization account for the constraint. We also obtained further evidence on starlings’ sensitivity to relative pitch in auditory pattern perception. We used probe stimuli to explore pattern discrimination in narrow local regions of the wide frequency range. The probe data showed that, in spite of the frequency range constraint, the starlings were able to process pitch patterns on a relational basis. The results join earlier data indicating that both absolute and relative pitch processing may be involved in the natural auditory communication of songbirds.     

Visual and Auditory Information Processing in Dyslexia: The Possibility of Subtypes

THIS DOUBLE‐BLIND experiment investigated various aspects of visual and auditory problems related to dyslexia. Seventeen children with dyslexia aged 7.25 to 10.25 years were compared with 17 normal readers matched for CA and intellectual ability. A speech perception task which measured the subjects’ auditory threshold level significantly separated the two groups. No difference was found when this task was performed at 35 dB above individual threshold levels. A significant difference between groups was found for the Form Constancy Subtest of the Frostig Developmental Test of Visual Perception (DTVP) (1966). A significant negative correlation found between these measures for the dyslexics, but not for the normal readers, supports previous evidence for auditory and visual subtypes in dyslexia. Various optometric measures were also examined. Four dyslexics, but no normal readers, suffered fixation disparity. This difference was significant. Six representative subjects of each group were compared for eye tracking in reading. The word span of the dyslexics was significantly smaller than that of the normal readers. A multiple discriminant analysis incorporating the auditory threshold task, form constancy, fusional reserves (distance, negative), accommodation right eye and heterophoria significantly discriminated the two reading groups. The perceptual variables were more heavily weighted than the optometric measures. It was concluded that while eye tracking and binocular fusion problems should always be considered in the assessment of dyslexics, factors involved in information processing in auditory and visual perception appear to be those which are more highly implicated.     

Basic auditory processing and developmental dyslexia in Chinese

The present study explores the relationship between basic auditory processing of sound rise time, frequency, duration and intensity, phonological skills (onset-rime and tone awareness, sound blending, RAN, and phonological memory) and reading disability in Chinese. A series of psychometric, literacy, phonological, auditory, and character processing tasks were given to 73 native speakers of Mandarin with an average age of 9.7 years. Twenty-six children had developmental dyslexia, 29 were chronological age-matched controls (CA controls) and 18 were reading-matched controls (RL controls). Chinese children with dyslexia were significantly poorer than CA controls in almost all phonological tasks, in semantic radical search, and in phonological recoding proficiency. Chinese children with dyslexia also showed significant impairments in most of the basic auditory processing tasks. Regression analyses demonstrated that different auditory measures of rise time discrimination were the strongest predictors of individual differences in Chinese character reading (1 Rise task) and phonological recoding (2 Rise task) respectively, with frequency discrimination also important for nonsense syllable decoding. Our results support the hypothesis that accurate perception of the amplitude envelope of speech is critical for phonological development and consequently reading acquisition across languages.     

The utility of Chinese tone processing skill in detecting children with English reading disabilities

The utility of Chinese tone processing skill in detecting children with English reading difficulties was examined through differences in a Chinese tone experimental task between a group of native English‐speaking children with reading disabilities (RD) and a comparison group of children with normal reading development (NRD). General auditory processing, English phonemic processing and English reading skills were also tested. We found differences between groups in Chinese tone processing skill, as well as general auditory processing and English phonemic skills. The RD group was significantly poorer than NRD on tasks of Chinese tone, phonemic and frequency modulated (FM) tone processing. Another finding was a different pattern of relationship between RD and NRD groups in Chinese tone, phonemic and FM tone processing as predictors of reading skills. For children with RD, FM tone processing was a significant predictor of pseudoword reading; for NRD, phonemic and Chinese tone processing skills predicted real word reading. These findings contribute to improved understanding of the roles of general auditory processing and phonological processing skills in RD, with implications for assessment and intervention with children who have English reading difficulties.     

基于 EMD-PSO-ELM 算法的大坝变形预测研究

基于极限学习机（ELM）构建的大坝变形预测模型易受连接权值、隐含层阈值及隐含层节点数影响,为获取更优的形变预测值,并改善模型预测可靠性,构建一种基于 EMD-PSO-ELM 算法,考虑时效、温度、水位等多因素的大坝变形预测模型。该模型首先从时频分析出发,利用经验模态分解（EMD）将变形时间序列分解成具有不同频率特征的分量|然后利用 PSO-ELM 模型解求形变预测值,重构获得大坝形变趋势。实验结果表明,融合时效、温度、水位等多因素的 EMD-PSO-ELM 大坝变形预测模型残差均方根误差为 1.83mm,平均绝对误差为 1.57mm,平均绝对百分比误差为 1.79%,比 ELM 模型与 EMD-ELM 模型相关误差值更小,在大坝变形预测方面性能更优。     

What to Do About Zero Frequency Cells When Estimating Polychoric Correlations

Categorical structural equation modeling (SEM) methods that fit the model to estimated polychoric correlations have become popular in the social sciences. When population thresholds are high in absolute value, contingency tables in small samples are likely to contain zero frequency cells. Such cells make the estimation of the polychoric correlations more difficult. Some SEM programs use solutions such as adding .5 to the zero frequency cells. However, the adequacy of this solution has never been systematically explored in the literature. In this article, the frequency with which contingency tables with zero cells occur in small samples is explored. Second, it is explored whether or not adding .5 is in any way preferable to leaving the cell value as zero. Binary and 3-category data and a variety of threshold values and correlation values are considered. The findings suggest that the two methods of dealing with zero frequency cells have quite different properties. With binary data, the method of adding .5 is recommended, unless thresholds are opposite-signed and the underlying correlation is suspected to be large. No adjustment is recommended for greater numbers of categories.     

Individual Differences in Categorical Perception Are Related to Sublexical/Phonological Processing in Reading

This article examines the relationship between individual differences in speech perception and sublexical/phonological processing in reading. We used an auditory phoneme identification task in which a?/ba/-/pa/?syllable continuum measured sensitivity to classify participants into three performance groups: poor, medium, and good categorizers. A lexical decision task manipulated syllable and word frequency. We found that the two tasks were associated. Poor categorizers did not present the typical syllable frequency effect; however, the other groups were sensitive to phonological information to differing degrees and showed the inhibitory syllable frequency effect only for low-frequency words. These results suggest that auditory phoneme identification efficiency may be related to the sublexical processes involved in reading words.     

Fine-grained auditory discrimination and performance on tests of receptive vocabulary and receptive language

This research investigated the relation between children’s performance on two measures of receptive language and children’s auditory discrimination of consonant-vowel sounds having frequency and temporal acoustic differences. The measures of fine-grained auditory discrimination produced significant multiple regression coefficients against both receptive vocabulary (Peabody Picture Vocabulary Test-Revised) and receptive language (Token Test for Children) scores. Validation analyses conducted by predicting receptive vocabulary and language scores for a new sample of children and relating them to the actual scores led to significant outcomes. It was concluded that fine-grained auditory discrimination is particularly important in the relatively early stages of language learning. The cooperation of the participating children, teachers, principals, and school district administrators is gratefully acknowledged. This research was supported, in part, by a grant from NINCDS (NIH).     

音乐速度感知的脑电波谱功率变异初步探索

选取没有音乐训练经验的8名本科生被试借助计算机进行实验,用16导脑电地形图仪记录被试脑电功率的变化,探索三种不同速度音乐感知过程中的脑电波谱功率的差异。结果表明:在音乐欣赏状态下,大脑听觉区以α波段活动为主;在欣赏不同速度的乐曲时,脑电波谱功率发生了明显变化,特别是在α波段慢速音乐诱发的平均功率值和峰频功率均高于中速和快速,且α波段不同乐速的峰频变化明显;由于大脑两侧的不对称性,T5的频段内平均功率、总功率、频谱功率、峰频功率显著小于T6的。由此,不同速度的乐曲会引起脑电功率的不同变化。