pp. Price 3. 40 rubles.Professor Lyamshev, the current editor of the Soviet Acoustics Journal, has long played a significant role in Soviet work on acoustooptics. In 1980, he contributed an invited paper on the subject to the ICA in Sydney, Australia. In this short volume, he carries out a careful exposition of the theoretical basis of laser excitation of sound, beginning with the simplest cases and proceeding systemically through the more complicated.The first chapter concerns itself with laser excitation of sound in a homogeneous half-space, first with a free surface and then with increasing complications of rough surfaces. Chapter 2 takes up various possible materials in the second half-space, be it another liquid, a solid, or an inhomogeneous surface layer. Here, he also introduces FM modulation of the intensity of the exciting laser.Chapter 3 continues this exploration of the source, considering pulses of various shape, interactions in one and three dimensions, and the effect of bubbles on the sound generation.The effect of moving sources has been of interest in Soviet acoustics since the days of Blokhintsev in the late 40s, and Chap. 4 is devoted to effects produced by moving laser thermooptical sound sources. The theoretical analysis is then completed by a chapter on the laser generation of sound in solids, including surface wave excitation and solid waveguides.The last chapter in the book is devoted to experimental results, mainly for laser-induced sound in water, with a small amount of attention paid to excitations of surface acoustic waves in solids.
Syntactic theories of intonation assume that intonation is congruent to syntax. It is, however, in the cases where it is not that intonation can restructure an utterance and become informative. In a first stage, we identify the prosodic units which play a part in the organisation of utterances. In a second stage, we examine how intonation contributes to the linear and hierarchical structure of utterances. The functioning of prosodic units in semantic and pragmatic organisation of the sentence allows us to bring to light syntactic constraints. This method seems the best way to evaluate the respective interactions of intonation with syntax and pragmatics. These syntactic constraints constitute formal marks which justify the content of prosodic rules (syntactic, semantic, accentual and rhythmic) which make it possible to predict or explain the intonation of utterances.
That lipreading plays a role in phoneme recognition, even when the acoustic signal alone is phonologically unambiguous, has been concluded from experiments in the perception of discrepant combinations of acoustic and visual speech signals. Little is known about the effect of visual information on explicitly phonetic judgments, the kind of judgments made by trained observers that are the basis for describing the phonological pattern of a language. In this study some isolated vowels, most of them similar to vowels in standard French, were produced in ten random orders by an experienced phonetician. The acoustic signals and frontal views of the lower half of the speaker's face were recorded on video tape. By computer editing, audiovisual stimuli were prepared in which pairs of vowels supposed to differ primarily in rounding were variously combined. Twenty French-speaking speech researchers carried out three tasks: to decide on the rounding of each vowel by sound alone, by sight alone, and by sound when accompanied by matching or discrepant images of the talker. Their summed responses indicate that, despite the instruction to base decisions on the auditory signal, visual evidence of speech activity significantly "perturbed" subjects' rounding judgments. However, the lipreading effect varied greatly across both subjects and vowels. Most subjects judged most vowels strictly on the basis of the auditory information, while for others lipreading exerted paramount influence. Only a small minority responded so as to indicate any integration of discrepant rounding information registered by ear and eye.
The aim of this study is to determine wether the threshold and pitch of falling glissandos are identical to those calculated for rising ones - and consequently to test the hypothesis that rising glissandos are less well perceived than falling ones. The results show a threshold between 18 and 19 Hz for a duration of 200 ms, with an initial frequency of 139 Hz. The pitch corresponds to the frequency of a point at two thirds of the duration of the vowel. These results confirm those obtained for rising glissandos. The above hypothesis is not verified. In conclusion, a model of hearing is proposed which account for the modes of perception of glissandos.
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