Inherent Duration Research Articles

Durational cues to stress, final lengthening, and the perception of rhythm

Binary stress languages have a well-known asymmetry between their tolerance of initial versus final lapse; the former being extremely rare and the latter being quite common. Lunden (to appear) proposes that final lengthening plays a role in this asymmetry, as the additional inherent phonetic duration of the final syllable can contribute to the continuation of a perceived rhythm, even in the absence of actual final stress. She notes this effect of final lengthening should only be available in languages that use duration as a cue to stress. However, some languages are described as having different cues to primary and secondary stress, and it is not clear which is more important for this perceptual effect. The results of four new studies show that final lengthening contributes to the perceptual rhythm of the word even when only one level of stress is cued with duration.

Multimode Continuous Processes Monitoring Based on Hidden Semi-Markov Model and Principal Component Analysis

Several studies have applied the hidden Markov model (HMM) in multimode process monitoring. However, because the inherent duration probability density of HMM is exponential, which is inappropriate for modeling the multimode process, the performance of these HMM-based approaches is not satisfactory. As a result, the hidden semi-Markov model (HSMM), which integrated the mode duration probability into HMM, is combined with principal component analysis (PCA) to handle the multimode feature, named as HSMM-PCA. PCA is a powerful monitoring algorithm for the unimodal process, and HSMM specializes in mode division and identification. HSMM-PCA inherits the advantages of these two algorithms and hence it performs much better than the existing HMM-based approaches do. In addition, HSMM-PCA can detect the mode disorder fault, which challenges the most multimode approaches.

The Korean Prevocalic Palatal Glide: A Comparison with the Russian Glide and Palatalization

Phonetic studies of the Korean prevocalic glides have often suggested that they are shorter in duration than those of languages like English, and lack a prolonged steady state. In addition, the formant frequencies of the Korean labiovelar glide are reported to be greatly influenced by the following vowel. In this study the Korean prevocalic palatal glide is investigated vis-à-vis the two phonologically similar configurations of another language - the glide /j/ and the secondary palatalization of Russian, with regard to the inherent duration of the glide component, F2 trajectory, vowel-to-glide coarticulation and glide-to-vowel coarticulation. It is revealed that the Korean palatal glide is closer to the Russian palatalization in duration and F2 trajectory, indicating a lack of steady state, and to the Russian segmental glide in the vowel-to-glide coarticulation degree. When the glide-to-vowel coarticulation is considered, the Korean palatal glide is distinguished from both Russian categories. The results suggest that both the Korean palatal glide and the Russian palatalization involve significant articulatory overlap, the former with the vowel and the latter with the consonant. Phonological implications of such a difference in coarticulation pattern are discussed, as well as the comparison between the Korean labiovelar and palatal glides.

Using a quadratic parameter sinusoid model to characterize the structure of EEG sleep spindles.

Sleep spindles are essentially non-stationary signals that display time and frequency-varying characteristics within their envelope, which makes it difficult to accurately identify its instantaneous frequency and amplitude. To allow a better parameterization of the structure of spindle, we propose modeling spindles using a Quadratic Parameter Sinusoid (QPS). The QPS is well suited to model spindle activity as it utilizes a quadratic representation to capture the inherent duration and frequency variations within spindles. The effectiveness of our proposed model and estimation technique was quantitatively evaluated in parameter determination experiments using simulated spindle-like signals and real spindles in the presence of background EEG. We used the QPS parameters to predict the energy and frequency of spindles with a mean accuracy of 92.34 and 97.73% respectively. We also show that the QPS parameters provide a quantification of the amplitude and frequency variations occurring within sleep spindles that can be observed visually and related to their characteristic “waxing and waning” shape. We analyze the variations in the parameters values to present how they can be used to understand the inter- and intra-participant variations in spindle structure. Finally, we present a comparison of the QPS parameters of spindles and non-spindles, which shows a substantial difference in parameter values between the two classes.

Object tracking and tracing: Hidden semi-Markov model based probabilistic location determination

The enhancement of radio frequency identification (RFID) technology to track and trace objects has attracted a lot of attention from the healthcare and the supply chain industry. However, RFID systems do not always function reliably under complex and variable deployment environment. In many cases, RFID systems provide only probabilistic observations of object states. Thus, an approach to predict, record and track real world object states based upon probabilistic RFID observations is required. Hidden Markov model (HMM) has been used in the field of probabilistic location determination. But the inherent duration probability density of a state in HMM is exponential, which may be inappropriate for modeling of object location transitions. Hence, in this paper, we put forward a hidden semi-Markov model (HSMM) based approach for probabilistic location determination. We evaluated its performance comparing with that of the HMM-based approach. The results show that the HSMM-based approach provides a more accurate determination of real world object states based on observation data.

Hidden semi-Markov model for anomaly detection

In this paper, hidden semi-Markov model (HSMM) is introduced into intrusion detection. Hidden Markov model (HMM) has been applied in intrusion detection systems several years, but it has a major weakness: the inherent duration probability density of a state in HMM is exponential, which may be inappropriate for the modeling of audit data of computer systems. We can handle this problem well by developing an HSMM for perfect normal processes of computer systems. Based on this HSMM, an algorithm of anomaly detection is presented in this paper, which computes the distance between the processes monitored by intrusion detection system and the perfect normal processes. In this algorithm, we use the average information entropy (AIE) of fixed-length observed sequence as the anomaly detection metric based on maximum entropy principle (MEP). To improve accuracy, the segmental K-means algorithm is applied as training algorithm for the HSMM. By comparing the accurate rate with the experimental results of previous research, it shows that our method can perform a more accurate detection.

Effects of clear speech on duration and fundamental frequency of vowels produced by monolingual and bilingual talkers

Prosodic characteristics of vowels produced by monolingual and bilingual talkers were investigated. Ten monolingual, 15 early Spanish-English bilingual (age of onset of immersion of age 12 or earlier), and ten late Spanish-English bilingual (age of onset of immersion of age 15 or later) talkers produced the target words ‘‘bead, bid, bayed, bed, bad,’’ and ‘‘bod’’ in conversational and clear speech styles. Vowel duration was computed, and F0 measurements were made at 20%, 50%, and 80% of the vowel duration. A significant group by style by vowel interaction showed that monolingual and early bilingual talkers enhanced inherent duration differences between target vowels by lengthening long vowels significantly more than short vowels in clear speech. The vowels of the late bilingual talkers, by contrast, became more alike in duration in clear than in conversational speech. The monolingual talkers showed a falling F0 pattern from 20% to 80% of the vowel duration in both styles; the late bilingual talkers showed a flat or rising F0 pattern in both styles; and the early bilingual talkers showed a flat or rising pattern in conversational speech, but a falling pattern in clear speech. [Work supported by NIH-NIDCD ♯5R03DC005561.]

Ultrafine Oxides during Detonation Expanse at A Fast Quenching Rate

Nanostructured spherical lithium manganese oxide (Li-Mn-O) with about 30nm in diameter was synthesized for the first time by explosive method. The water-solubility explosive was prepared using a simple facility at room temperature. The growth of lithium manganese oxides via detonation reaction was investigated with respect to the presence of an energetic precursor, such as the metallic nitrate and the degree of confinement of the explosive charge. The detonation products were characterized by scanning electron microscopy. Powder X-ray diffraction and transmission electron microscopy were used to characterize the products. Lithium manganese oxides with spherical morphology and more uniform secondary particles, with smaller primary particles of diameters from 10 to 50 nm and a variety of morphologies were found. Lithium manganese oxides with a fine spherical morphology different from that of the normal is formed after detonation wave treatment due to the very high quenching rate. It might also provide a cheap large-scale synthesis method. Explosive detonation is strongly nonequilibrium processes, generating a short duration of high pressure and high temperature. Free metal atoms are first released with the decomposition of explosives, and then theses metal and oxygen atoms are rearranged, coagulated and finally crystallized into lithium manganese oxides during the expansion of detonation process. For detonation of the water-solubility explosive, the detonation pressure, the detonation temperature and the adiabatic gamma were close to 3 GPa, 2300 K and 3. The inherent short duration, high heating rate (1010 – 1011 K/s) and high cooling rate (108 – 109 K/s) prevent the lithium manganese oxides crystallites from growing into larger sizes and induce considerable lattice distortion.

Temporal characteristics of Chinese-accented English: Preliminary findings

This study investigated several temporal features of English to determine the extent of their occurrence in the speech of talkers of Chinese-accented English who had relatively limited experience with spoken English. Specifically, the extent to which these speakers produced the following temporal contrasts was examined: (1) tense versus lax vowel duration, (2) vowel duration before voiced versus voiceless consonants, and (3) vowel and consonant duration in sentence-final versus nonfinal position. Preliminary data from sentences produced by eight non-native and eight native talkers indicates that the native English speakers and the Chinese-accented talkers did not differ in the extent to which they realized the inherent duration difference between tense and lax vowels. However, the native English subjects tended to show substantially greater vowel lengthening before voiced versus before voiceless consonants than the Chinese-accented talkers. In addition, while the two groups did not differ significantly in the extent to which they lengthened sentence-final consonants relative to nonfinal consonants, the native English talkers showed greater sentence-final vowel lengthening than the Chinese-accented talkers. When group differences for a given temporal parameter were found, 1 or 2 of the non-native subjects typically fell within the range of performance shown by the native speakers.

Identification of Swedish vowel quantity by pre-adults

Research on the perception of Swedish vowel quantity by adult native listeners shows that vowel duration is a primary cue for identifying vowel quantity. However, when a vowel has a relatively long duration (e.g., due to its inherent duration, or its context), adult listeners may make use of both duration and spectra to identify vowel quantity. Use of the vowel spectrum in these special cases might be seen as the result of perceptual fine tuning to improve the processing efficiency in vowel identification. If so, we would expect a developmental change in how children use vowel duration and spectra to identify vowel quantity, with the use of vowel spectra as a cue coming relatively late. This investigation examines how young native listeners, from 9 to 15 years old, use vowel duration and F1-F2 to identify Swedish vowel quantities. For each of three vowel types, 100 /kVt/ words were resynthesized with ten degrees of vowel duration and ten degrees of F1 and F2 adjustment. Each child responded to a subset of these in a rhyming task. Results show a late developing ability to identify vowel quantity and trace the use of vowel duration and F1-F2 as perceptual cues to vowel quantity.

Duration of embryonic diapause in the brush-tailed bettong, Bettongia penicillata (Potoroidae): effect of age of quiescent corpus luteum.

It has been shown that changes to the frequency of sucking by the pouch young do not affect the time of reactivation of the quiescent corpus luteum and diapause embryo in Bettongia penicillata; these observations led to the suggestion that the corpus luteum may have an inherent maximum duration of quiescence. The aim of the present study was to investigate the effect of the age of the corpus luteum on the timing of its reactivation. Ovulation fails to occur post partum in female B. penicillata isolated from males, and the introduction of a male B. penicillata induces oestrus in females suckling a young in the pouch. Oestrus was induced from Day 23 of lactation to Day 76, in different females, and the corpus luteum became quiescent. All parturitions occurred between Day 95 and Day 103 of lactation (average, Day 98.8), at the time expected if the corpus luteum had been formed post partum. Duration of quiescence of the corpus luteum ranged from 60 days to 10 days, compared with 83.9 +/- 0.43 days in females that mated post partum. The results show that the age of the corpus luteum does not affect the timing of its redevelopment and release of the embryo from diapause near the end of the period of the young being suckled within the pouch.

Acoustic manifestations of mora timing in Japanese

Segment durations in 20 minimal-paired words in Japanese were examined to identify regular patterns of acoustic manifestations of mora timing in Japanese. The results indicate that segments consistently stretch or compress, providing temporal compensation within a mora and between moras, to attain targeted length at the word level. A segment is 11% longer in the pre-geminate-stop position than in the pre-single-stop position; in the word final position, a segment is 9% shorter following a geminate stop than a segment following a single stop; and [t] in the same phonotactic environment shows varied durations according to different moraic conditions. Fricatives followed by a devoiced vowel are considerably longer than any other inherently long, nonmoraic segments, and are comparable to moraic segments and the average mora duration. Syllable durations are not isochronous, varying by as much as 50%. The word duration is affected more by the number of component sounds and their inherent durations in two-mora than in three-or four-mora words. When the word durations are converted into ratios, they are markedly similar to the mora values. The results suggest a timing control mechanism adjusting segments to obtain targeted word durations. These phenomena describe mora timing in Japanese.

Significance of knowledge sources for a text-to-speech system for Indian languages

This paper discusses the significance of segmental and prosodic knowledge sources for developing a text-to-speech system for Indian languages. Acoustic parameters such as linear prediction coefficients, formants, pitch and gain are prestored for the basic speech sound units corresponding to the orthographic characters of Hindi. The parameters are concatenated based on the input text. These parameters are modified by stored knowledge sources corresponding to coarticulation, duration and intonation. The coarticulation rules specify the pattern of joining the basic units. The duration rules modify the inherent duration of the basic units based on the linguistic context in which the units occur. The intonation rules specify the overall pitch contour for the utterance (declination or rising contour), fall-rise patterns, resetting phenomena and inherent fundamental frequency of vowels. Appropriate pauses between syntactic units are specified to enhance intelligibility and naturalness.

Disambiguation of Segmental Dependencies by Extended Phonetic Context

This research investigated listeners' ability to recognize adjacent vowels and consonants that are conveyed in part by a common temporal cue – vowel duration. The stimuli consisted of a large sample of natural speech containing nonsense syllables made by combining four vowels that differed in inherent duration (/i/, /ε/, /i/, /e/) with two syllable-final consonants that differed in phonological voicing (/z/ and /s/), a distinction that is partially cued by vowel duration. Experiment 1 examined the effect of vowel identity, fricative identity, and contextual factors on vowel duration, voiced-frication duration, and voiceless-frication duration in speech production, and the potential effectiveness of these durational measures as classification cues. In Experiment 2, listeners identified the syllables after they had been excised from sentential context. Accuracy in recognizing /s/ varied with the inherent duration of the preceding vowel, with the number of errors increasing with inherent vowel duration. This suggests that listeners did not sufficiently account for the effect of vowel identity when interpreting vowel duration as a cue to syllable-final voicing. In Experiment 3, listeners heard the syllables in sentential context. Accuracy improved, and no relation was found between inherent vowel duration and accuracy in recognizing /s/. This indicated that the sentential context of a syllable conveys information that is useful to listeners in correctly determining the segmental basis of the internal temporal structure of a syllable.

The Duration of Telugu Speech Sounds: An Acoustic Study

An acoustic investigation is made of the pattern of durations of individual phonetic segments in Telugu using sound-spectrograph and electro-kymograph. The discussion of phonetic variation in duration includes the following factors: (i) Intrinsic duration of segments of both vowels and consonants and its correlation with (a) vowel height, (b) consonant place, (c) consonant manner and (d) voicing; (ii) Influence of neighboring sounds on long vs short vowel and/or consonant; (iii) The relevance of position in an utterance; (iv) The behavior of consonants in sequences; and (v) The influence of number of syllables and segments in a word. Physical measurements reveal that each segment has its own inherent duration depending on its type, position in an utterance, surrounding phonetic context and the number of sounds/syllables.

Evidence for mora timing in Japanese.

Japanese has long been described as a "mora-timed" language by linguists. Japanese pedagogy has traditionally claimed that moras are constant in duration. Four experiments are reported investigating segmental timing in Japanese in order to test several straightforward hypotheses about mora timing. First, it is demonstrated that words with an increasing number of moras increase in duration by nearly constant increments. The next two experiments explored the mechanisms by which constant mora durations are achieved given that there are large universal differences in the inherent duration of various segment types (e.g., /u/vs/a/), and given that some syllables are supposed to be two mora long (such as, those with long vowels or final consonants). In each case, it was found that the duration of a word stays very close to a target duration that depends on the number of moras in it. This is achieved by stretching or compressing the duration of neighboring segments and adjacent moras. Thus increasing the number of segments in two-mora syllables results in lengthening, not the expected shortening, of other segments in the heavier syllable.

Fitting long vowels and stops into the mora in Japanese

Earlier studies of two syllable words demonstrate that segment durations in words are contextually adjusted so as to yield word durations that are nearly equal despite differences in the inherent durations of the vowels and consonants that make up the words. The present experiment compares the temporal structure of a pair of two‐more CVCV words to that of three pairs of three‐mora words of three different types; a pair that has an “extra” vocalic mora (CVVCV), a pair that adds a consonantal more (CVCCV), and a third pair that adds a syllabic more (CVCVCV). Within each pair the medial stop differs in voicing. The results show that adjustments are made between adjacent morae, not just between adjacent segments, to compensate for inherent differences in mora durations. This problem arises since a segmental mora (i.e., long V or C) is shorter than a syllabic mora (CV), yet the durations of all three words containing them were found to be nearly equal. Furthermore, the adjustments at the mora level are made independently of the effects due to adjustments at the segment level. [Work supported by NIH.]

Temporal Compensation and Universal Phonetics

Abstract Two experiments were conducted, on Japanese and on Arabic, to explore the extent to which vowels adjacent to longer and shorter apical consonants would compensate for the consonant durations. In the Arabic experiment, little evidence of timing compensation was found, whereas Japanese vowels on both sides of a consonant varied inversely with the consonant, and the consonant constriction duration varied inversely with the inherent vowel durations. The result is that the duration of the two-syllable test words scarcely changed at all. These results support the notion that Japanese morae have constant durations although they undermine the definition of the mora as a simple CV unit. These findings suggest that rhythmic structures in speech need not be thought of as constructed by the perceiver; they may also be present in the acoustic signal itself. More generally, our results imply the existence of language-specific timing rules that cannot be captured in the segmental terms insisted upon by current linguistic phonetic theory.

Temporal and spectral cues to syllable stress

The interaction of temporal and spectral information for judgments of syllable stress was studied using a formant pattern of each of the vowels /i/, /I/, and /ɝ/ of English. The patterns were arranged to form all nine possible disyllables in the nonsense frame /s‐ds‐d/. In all disyllables the duration of the first vowel varied in 10‐ms steps from 50 to 150 ms while the duration of the second vowel was changed to keep the work length constant. Fundamental frequency and intensity were kept constant within and across the words. Eight subjects judged the stress, length, and phonetic identity of the target words in isolation. The 50% crossover points for the stress and length judgments as a function of vowel duration were obtained by PROBIT analysis and subjected to an analysis of variance with phonetic identity as the treatment. Further tests show a significant difference between the locations of stress boundaried for different vowel pairs. The results are not so clearly a function of the inherent duration of the phonemes involved as previous research suggests.

Time and intensity cues to prosodic features of sentences

Profoundly deaf persons hear only time and intensity variations in amplified speech and must rely on lipreading to perceive speech segments [N. Erber, J. Acoust. Soc. Am. 51, 1224–1227 (1972)]. These persons may perceive prosodic features of sentences by hearing. It is not known whether linguistically significant variations in duration and intensity of speech segments are perceived by reference to the inherent duration of those segments and thus, are dependent upon intelligibility. Subjects responded to three sentence tests wherein the sentences differed in either phrase‐structure, major constituent boundary (MCB), or contrastive stress. Responses were by forced choice to the prosodic features; subjects were not required to identify words. Stimuli were presented under audition‐alone, vision‐alone, and audiovisual conditions. The acoustic signal was noise, amplitude modulated by the sentence materials. The audiovisual condition resulted in highest mean scores. Identifying phrase‐structure, audition‐alone scores were near chance levels. Vision‐alone and audiovisual scores were close in value, suggesting that time and intensity cues supplemented visual cues to a small extent. Identifying MCB location, vision‐alone scores were near chance levels. Audition‐alone scores were equivalent to audiovisual scores, suggesting that time and intensity variations provided primary cues. Identifying contrastive stress location, score data suggested that the acoustic signal allowed detection of contrastive stress and the exact word was located with visual cues. These results indicate that an unintelligible speech signal may supplement lipreading by providing certain prosodic information, increasing perceptual strategies available to profoundly deaf persons.