Fundamental Frequency Variation Research Articles

Investigation on the dynamic characteristics of anchor rods considering size effect and pull-out loads based on IIR-FDM

When the surrounding rock of tunnel anchor bars has boundaries, the signals obtained from non-destructive testing (NDT) of anchor rods will be simultaneously affected by size effects and pull-out loads, leading to potential misinterpretation of the test results. In order to accurately assess the anchorage quality of anchor rods under this interference, NDT and numerical simulations of anchor rods subjected to different anchorage quality were conducted under the influence of size effects and pull-out loads. A signal filtering method, which combines the infinite impulse response-finite difference method, was proposed for identify the impact of size effects. The study analyzed the variations in wave velocity and fundamental frequency of anchor rods with anchorage defects and intact anchor rods under the influence of size effects and pull-out loads. The results indicate that the IIR-FDM method, in comparison to the traditional wavelet method, provides better agreement between the calculated wave velocities and existing findings. With the increase of size effect, the wave velocity and amplitude ratio of the anchor rods decrease, and the fundamental frequency increases first and then decreases. As the working load on the anchor rods increases, the wave velocity initially decreases, then rises, while the fundamental frequency initially increases and then experiences a slight decrease. The presence of anchorage defect results in an increase in the wave velocity and amplitude ratio of the anchor rods, while causing a decrease in the fundamental frequency. This effect of defects on wave velocity and fundamental frequency is more pronounced at lower loads. The wave velocity after IIR-FDM processing has a small error with the simulated wave velocity, indicating the reliability of the processing method.

A novel semi-empirical approach to non-destructively evaluate the effect of infills on frame buildings

Masonry infilled frame (MIF) structures are commonly used as building system in many regions, and particularly in Latin American, Mediterranean, and Pacific countries, which are areas highly exposed to seismic events. It is well known that the influence of the infilled frames on the seismic response is affected by several sources of uncertainties which create unsafe unaccuracies in the seismic behaviour of a building. The use of existing complex models is an option which require a large number of specialized input values and data mostly obtained from in-situ destructive tests, thus making them infeasible in many practical cases. This research is a first attempt to provide an approach which provides prediction of the structural behaviour of a MIF with quantified uncertainty, and using as inputs values that can be obtained through a low-cost non-destructive test. The proposed method exploits the known interaction between the in-plane (IP) and out-of-plane (OoP) behaviour of the masonry wall by providing a semi-empirical model which predicts the IP stiffness of the MIF in terms of the measured OoP fundamental frequency. The semi-empirical approach has been nurtured with five experimental tests over one-fourth scale MIFs, where the OoP fundamental frequency variation has been obtained in terms of the IP deformation history. The results indicate that the proposed method can become a practical tool to experimentally quantify the contribution of the masonry infills of existing frame buildings, and also to theoretically predict it during design phase. However, a larger dataset of tests should be used on the calibration of the method before its application in real cases.

On the role of pauses – a qualitative and quantitative analysis of selected political speeches in the European Parliament

This paper presents an analysis of speech pauses occurring in selected political speeches, with a focus on both filled and silent types. The paper aims to highlight differences among pause categories in spoken language and assess potential gender differences. By analyzing speeches from male and female speakers in specific syntactic contexts, the paper reveals limited variations in fundamental frequency and pause duration. While certain subcategories exhibit slight differences in frequency, consistent patterns are lacking. Findings indicate that filled, hesitation, politeness, and perturbation pauses tend to be longer, whereas specification and personal stance pauses tend to have lower frequencies. Enumeration, opposition, and segmenting pauses strategically support a speaker's point, aligned with sentence structure. Investigating fundamental frequency trends before pauses demonstrates that a decrease in frequency signifies unit culmination, while an increase suggests non-final positions within units. The paper concludes that disparities exist among pause types, though differences between male and female speakers are generally minor. This emphasizes the need to consider multiple factors, including duration, frequency, and syntactic context, for comprehensive pause definitions. Overall, the paper provides insight into speech pause attributes, variations, and their significance in conveying meaning, thus enriching our understanding of speech patterns and communication strategies.

Context effects on duration, fundamental frequency, and intonation in human-directed domestic cat meows

In this study, we investigated the prosody of domestic cat meows produced in different contexts. Prosodic cues – i.e., variation in intonation, duration, voice quality and fundamental frequency – in humans as well as in nonhuman animals carry information about idiosyncratic traits of the signaller, including sex, age, and physical and mental state. The duration, fundamental frequency (F0) and intonation in a sample of 969 meows recorded in seven different contexts (i.e., cuddle, door, food, greeting, lifting, play, cat carrier) were analysed using linear mixed effects regression and generalized additive models. In this, we controlled for cat age and sex, as meows produced by old cats had lower mean F0 than those produced by young cats, and female cats produced meows with higher mean F0 than male cats. We found significant effects of context on duration and mean F0, but not on F0 range. Furthermore, the results showed that the intonation of meows produced by cats in a cat carrier displayed a falling pattern, while that of meows produced in cuddle and door contexts was relatively level, and that of meows produced in the other contexts consisted of combinations of rising and falling. The average slope of meows produced in cat carrier and play contexts was negative, while that of meows produced in the other contexts was positive. We argue that this prosodic variation reflects the cats’ mental or emotional state, because of valence and arousal differences associated with the various contexts that were included in the study. Further studies will need to confirm this. In addition, we also plan additional analyses of spectral and voice quality parameters in meows and other cat vocalisation types.

Recognition of Speech With Dynamic Pitch Manipulation in Noise: Effects of Manipulation Methods.

Dynamic pitch, which is defined as the variation in fundamental frequency in speech, is one of the acoustic cues that affect speech recognition in noise. Built on the evidence that a symmetrical manipulation of dynamic pitch led to poorer speech recognition, the present study examined the effect of an asymmetrical manipulation method on speech recognition in noise by younger and older adults. Speech recognition accuracy in noise was measured from younger adults with normal hearing in Experiment 1, and speech reception threshold (in dB SNR) from older adults with normal hearing to mild-moderate hearing loss in Experiment 2. The dynamic pitch contours of the speech stimuli were manipulated using both symmetrical and asymmetrical methods. Younger adults recognized speech better in noise with asymmetrical than symmetrical manipulation, and with weakened than strengthened dynamic pitch. A substantial amount of variability was observed in a group of older listeners. This variability was predominately predicted by the listeners' age but not hearing thresholds or their ability to perceive dynamic pitch in fluctuating noise. The asymmetrical manipulation of dynamic pitch had a less negative effect than the symmetrical manipulation. This effect also interacted with pitch-change direction. These findings suggest the influence of perceptual naturalness on speech recognition with signal modification. Directions for future research are also discussed.

Production of emotions conveyed by voice in Parkinson's disease: Association between variability of fundamental frequency and gray matter volumes of regions involved in emotional prosody.

Parkinson's disease (PD) is associated with impairment in producing emotions conveyed by voice which could depend on motor limitations of the vocal apparatus and/or alterations in emotional processing. This study explores the relationship between the standard deviation of fundamental frequency (F0SD) of emotional speech and the volume of specific gray matter regions. Fifteen PD patients and 15 healthy controls (HC) were asked to produce different emotions vocally elicited by reading short stories. For each vocal track, the F0SD was calculated as index of variability. All subjects underwent a structural magnetic resonance imaging and a voxel-based morphometry analysis. An ad hoc mask of brain regions implicated in emotional prosody was constructed to test the relationship between F0SD and the level of brain atrophy. PD patients showed lower F0SD values than HC in the expression of anger. Neuroimaging results showed brain atrophy in PD patients in a widespread bilateral network, including frontal areas, left cingulate cortex, parietal areas as well as occipital cortices. In the PD group, a positive correlation was observed between F0SD values of anger and volumes of the bilateral supramarginal gyrus, left thalamus, right inferior frontal gyrus, and amygdala. The lower F0SD values observed in PD patients in anger production are consistent with their lower ability to express anger effectively through voice compared to HC. Our data demonstrated the involvement of right-lateralized areas, such as the inferior frontal gyrus and amygdala, which are typically involved in emotional prosody. Disturbances in emotion processing might contribute to speech production deficits in PD, probably in addition to the motor impairment of the articulatory system. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Influence of vowels on note pitching in a cappella vocal quartet performance

This study aimed to investigate the relationship between the fundamental frequencies employed when singing different vowels on the same pitch for each member in turn of a professional soprano, alto, tenor, bass (SATB) a cappella vocal quartet in terms of the measured fundamental frequency during the production of a set of individual vowels within a four-part carrier phrase. This is an experimental singing production study on the tuning of vowels in the context of a cappella quartet singing. To facilitate this, one singer at a time in a professional a cappella vocal quartet changed the vowel they are singing on a single note concurrent with a consonant a cappella triad being sustained by the other three singers singing a fixed vowel. The first few bars of the a cappella anthem "If ye love me" by Thomas Tallis provided a carrier phrase that ended with a held chord on the chord on the word "me" by three singers against which the remaining singer produced a set of different vowels on their note of the chord. This is carried out for each of the four singers. The hypothesis being investigated is to remain accurately in-tune; fundamental frequency should be varied depending on the vowel being sung. Fundamental frequencies were measured using electrolaryngographs to ensure that there was no acoustic interference that could affect the accuracy of the fundamental frequency measurements if they were obtained from the audio output. The results provide clear evidence of changes being made to the fundamental frequencies of different vowels in an a cappella quartet context, and these changes confirm variations found elsewhere relating to the perceived pitches of different vowels. Measurable and consistent fundamental frequency variations occur when one part tunes different vowels against a reference chord sung by the other three singers in a choral quartet context on a fixed vowel. This has a direct consequence for tuning in a cappella choral music. The importance of carefully tuning individual notes for different vowels in a cappella choral singing requires focused listening to the pitches of the sounds being produced by the other singers in the choir. Usually, all parts are singing common vowels where it is important that the vowels are matched by being carefully blended together and tuning is aimed at being beat-free in just intonation. When compositions require parts to sing different vowels, both intrinsic (production related) and auditory (hearing related) pitch variations become relevant and challenge beat-free tuning.

Effect of clear speech on acoustic measures of dysprosody in Parkinson disease for different reading tasks

Purpose The purpose of the study was to determine the effect of clear speech instruction on acoustic measures of dysprosody between reading passages of differing linguistic content for speakers with and without Parkinson Disease (PD). Method Ten speakers with PD and 10 controls served as participants and read five simple and three standard reading stimuli twice. First, speakers read habitually and then following clear speech instruction. Acoustic measures of fundamental frequency variation (semitone standard deviation, STSD), articulation rate, and between-complex pause durations were calculated. Result Results indicated speakers with PD exhibited less fundamental frequency variation than controls across reading stimuli and instructions. All speakers exhibited lower STSD and longer between-complex pause durations for the standard compared to simple reading stimuli. For clear speech, all speakers reduced articulation rate and increased between-complex pause durations in both simple and standard reading stimuli. However, speakers with PD exhibited a significantly less robust reduction in articulation rate for clear speech than control speakers for all reading stimuli. Conclusion Linguistic content of reading stimuli contributes to differences in fundamental frequency variation and pause duration for all speakers. All speakers reduced articulation rate for clear speech compared to habitual instruction, but speakers with PD did so to a lesser extent than controls. Linguistic content of reading stimuli to examine dysprosody in PD should be considered for clinical application.

Whistle repertoire and structure reflect ecotype distinction of pantropical spotted dolphins in the Eastern Tropical Pacific

The pantropical spotted dolphin in the Eastern Tropical Pacific (ETP) is found in two genetically and phenotypically diverged ecotypes, coastal and offshore. These habitats have distinct acoustic characteristics, which can lead to the evolution of distinct acoustic communication. Whistles are sounds widely used by dolphins to mediate species and individual recognition and social interactions. Here, we study the whistle acoustic structure and repertoire diversity of offshore and coastal pantropical spotted dolphins. Our results show that there is significantly more within- and across-group variation in whistle fundamental frequency between ecotypes than between offshore groups and between coastal groups. A Random Forest classification analysis performed with an accuracy of 83.99% and identified duration, peak and minimum frequency as the most informative variables for distinguishing between ecotypes. Overall, coastal spotted dolphins produced significantly shorter whistles that were significantly lower in frequency (peak, minimum and maximum, and start and end) than offshore dolphins. Ecotypes produced whistle repertoires that were similar in diversity, but different in contour composition, with the coastal ecotype producing more upsweep whistles than offshore dolphins. The results of this study suggest that acoustic adaptations to coastal and offshore environments could be important contributors to intraspecific variation of dolphin whistle repertoires.

Interaction of Voice Onset Time with Vocal Hyperfunction and Voice Quality

The main aim of the present work was to investigate whether vocal hyperfunction (VH), perceptual voice quality (VQ), gender, and phonetic environment influence Voice Onset Time (VOT). The investigated group consisted of 30 adults, including 19 women (X = 46.1 ± 13.7 years) and 11 men (X = 47.5 ± 11.0 years), who had either phonotraumatic vocal hyperfunction (PVH) and non-phonotraumatic vocal hyperfunction (NPVH). VQ was judged considering the overall severity of dysphonia (OS) and the subcharacteristics of roughness, breathiness, and strain. Phonetic variables such as vowel stress, syllable stress, and mode of speech task were analyzed. Four samples of syllables with [p] plus vowel or diphthong were retrieved from CAPE-V sentences recordings. Acoustic analysis with Praat comprised VOT, mean fundamental frequency (fo), intensity (SPL dB(A)), and coefficient of variation of fundamental frequency (CV_fo %). VOT was significantly influenced by OS (p ≤ 0.001) but not by vocal VH condition (PVH versus NPVH) (p = 0.90). However, CV_fo was affected by the VH condition (p = 0.02). Gender effects were only found for mean fo (p ≤ 0.001) and SPL (p = 0.01). All VQ sub characteristics (OS, roughness, breathiness, and strain) correlated with VOT (p ≤ 0.001) and SPL (p ≤ 0.001) but not with fo. In summary, VOT was affected by voice quality, while it was not affected by vocal hyperfunction conditions. Therefore, VOT has the potential to objectively describe the onset of voicing in voice diagnostics, and may be one underlying objective characteristic of perceptual vocal quality.

Voice Improvement After Essential Tremor Treatment via Focused Ultrasound and Deep Brain Stimulation.

The primary objective of this study was to determine whether two neurosurgical procedures, deep brain stimulation (DBS) and focused ultrasound (FUS), to treat essential tremor (ET) of the upper limb also reduce vocal tremor (VT) in patients with comorbid dysphonia. Twelve patients with ET and concomitant VT scheduled for neurosurgical intervention (FUS or DBS) or returning for follow-up after DBS implantation were assessed. FUS patients were assessed pre- and post-intervention and DBS patients were assessed with the electrodes turned on and off post-implantation. Three voice recordings of a sustained /a/ were obtained for each participant condition. Percent fundamental frequency variability (FFV) was calculated for each recorded sustained vowel. Additionally, blinded expert perceptual VT rating (VTR) was performed to assess subjective changes in tremors. Of the 12 patients, seven underwent unilateral FUS, and five underwent bilateral DBS. Mean FFV without neurosurgical intervention was 18.3%, SD = 7.8 and with neurosurgical intervention was 6.3%, SD = 3.0 (t (70) =8.7, p < 0.001). Mean FFV decreased in the FUS cohort from 22.0%, SD = 7.1 pre-ablation to 6.7%, SD = 2.4 post-ablation (t (40) = 7.7, p < 0.001). Mean FFV also decreased in the DBS cohort from 15.7%, SD = 7.0 to 6.0%, SD = 3.3 when stimulation was turned on (t (28)=5.7 p < 0.001). In the FUS group, mean VTR decreased from 4.0 to 1.4 post-ablation (Z = 7.8, p < 0.001). In the DBS group, mean VTR decreased from 3.3 to 2.1 with stimulation (Z = 4.1, p < 0.001). Neurosurgical interventions for ET (bilateral DBS and unilateral FUS) demonstrate acoustic and perceptual benefits for VT. 4 Laryngoscope, 134:367-373, 2024.

Predicting glycemic control status and high blood glucose levels through voice characteristic analysis in patients with cystic fibrosis-related diabetes (CFRD)

Cystic fibrosis-related diabetes (CFRD) is associated with reduced life expectancy in adults with cystic fibrosis (CF). Voice analysis may be a convenient method for diagnosing and monitoring CFRD. This study aims to determine the relationship between voice characteristics and markers of glucose and glycemic control and to identify if voice analysis can predict high blood glucose levels and glycemic control in adults with CFRD. We conducted a prospective cross-sectional study in adults with CF from March to December 2021. We recorded 3-second voice samples of a sustained /a/ vowel and analyzed voice characteristic using the Computerized Speech Lab with the Multi-Dimensional Voice Program. In female participants with CFRD, the noise-to-harmonic ratio was significantly lower in those with HbA1c ≥ 7. Furthermore, fundamental frequency variation was significantly lower in both male and female participants with CFRD who had a glucose level of 200 mg/dL or higher at the time of collection. This finding was also associated with a high level of point-of-care glucose. The human voice has potential as a non-invasive tool for measuring glucose levels and glycemic control status in CFRD patients in the future.

Radial oscillations of dark matter admixed neutron stars

Within the relativistic mean-field model, we investigate the properties of dark matter (DM) admixed neutron stars, considering non-rotating objects made of isotropic matter. We adopt the IOPB-I hadronic equation of state (EOS) by assuming that the fermionic DM within super-symmetric models has already been accreted inside the neutron star (NS). The impact of DM on the mass-radius relationships and the radial oscillations of pulsating DM admixed neutron stars (with and without the crust) are explored. It is observed that the presence of DM softens the EOS, which in turn lowers the maximum mass and its corresponding radius. Moreover, adding DM results in higher frequencies of pulsating objects and hence we show the linearity of fundamental mode frequency of canonical NS with DM Fermi momentum. We also investigate the profile of eigenfunctions solving the Sturm-Liouville boundary value problem, and verify its validity. Further, we study the stability of NSs considering the fundamental mode frequency variation with the mass of the star, and verify the stability criterion $\partial M/\partial\rho_c > 0$. Finally, the effect of the crust on the large frequency separation for different DM Fermi momenta is shown as well.

Resonant Frequency Deviation Analysis and Modified Notch Filter-Based Active Damping for SiC-Based PMSM Drive With Sine Wave Filter

In the permanent-magnet synchronous machine (PMSM) drive system, the adoption of silicon carbide (SiC) devices brings up new challenges, such as overvoltage, electromagnetic interference emission, and bearing current. To surmount these barriers, the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> filter designed as the sine wave filter can be introduced into the machine drive system. However, filter and stator inductance can create unwanted electrical resonance issues. For the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> -equipped PMSM drive system, there are two main factors that cause the drift of resonant frequency and change of stable region: (1) synchronous coordinate transformation with variable fundamental frequency, (2) parameter variations due to the magnetic saturation effect. In this paper, the deviation of resonant frequency caused by coordinate transformation is discussed. Then, the inherent damping effects and stability range in the rotating reference frame are derived in detail. Furthermore, considering the parameter mismatch disturbances, an active damping method based on the enhanced notch filter is presented, of which notch frequency is designed lag behind the nominal resonant frequency. The accurate discretization method and theoretical stability analysis in discrete <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">z</i> -domain are conducted. The experimental results are presented to verify the effectiveness and robustness of the proposed analysis and method.

Acoustic correlates of perceived anger in the Ferguson clear speech database

Previous work has shown that clear speech is perceived as sounding angry significantly more often than conversational speech (Morgan and Ferguson, 2017; Young, 2021). The current study examined possible acoustic correlates of perceived anger in clear speech. A principal component analysis was completed to guide selection of acoustic variables for analysis. The remaining six acoustic measures, fundamental frequency median, fundamental frequency variability, relative mid-frequency energy from 1000 to 3150 Hz, speaking rate, and degree of amplitude modulation at 2 Hz and 16Hz envelopes, were analyzed using mixed effects regression. Results indicated that after controlling for speaking style, fundamental frequency approached significance but did not significantly predict perceived anger. However, speaking rate significantly predicted perceived anger after controlling for speaking style, with slower rates leading to an increase in perceived anger. Further, there was a significant interaction between speaking rate and speaking style, where slower speech was only perceived as angry in the clear speech style. Finally, a decrease in the degree of low-frequency amplitude modulation (i.e., equal emphasis on both content and function words) led to an increase in perceived anger after controlling for speaking style. The results have implications for counseling individuals in the use of clear speech.

The Relationship Between Pitch Discrimination and Fundamental Frequency Variation: Effects of Singing Status and Vocal Hyperfunction

The purpose of this study was to investigate the relationship between pitch discrimination and fundamental frequency (fo) variation in running speech, with consideration of factors such as singing status and vocal hyperfunction (VH). Female speakers (18-69 years) with typical voices (26 non-singers; 27 singers) and speakers with VH (22 non-singers; 30 singers) completed a pitch discrimination task and read the Rainbow Passage. The pitch discrimination task was a two-alternative forced choice procedure, in which participants determined whether tokens were the same or different. Tokens were a prerecorded sustained /ɑ/ of the participant's own voice and a pitch-shifted version of their sustained /ɑ/, such that the difference in fo was adaptively modified. Pitch discrimination and Rainbow Passage fo variation were calculated for each participant and compared via Pearson's correlations for each group. A significant strong correlation was found between pitch discrimination and fo variation for non-singers with typical voices. No significant correlations were found for the other three groups, with notable restrictions in the ranges of discrimination for both singer-groups and in the range of fo variation values for non-singers with VH. Speakers with worse pitch discrimination may increase their fo variation to produce self-salient intonational changes, which is in contrast to previous findings from articulatory investigations. The erosion of this relationship in groups with singing training and/or with VH may be explained by the known influence of musical training on pitch discrimination or the biomechanical changes associated with VH restricting speakers' abilities to change their fo.

Intonation Parameters in Gender Diverse People

Although intonation is often addressed in speech training for gender diverse individuals, the relationship between intonation and femininity/masculinity ratings remains unclear. The aim of this study was to examine differences in intonation parameters in gender diverse individuals. Moreover, the relationship between acoustic intonation parameters and femininity/masculinity ratings was investigated. Speech samples of semistructured speech were elicited from cisgender (cis) (107 ciswomen, 104 cis men), transgender (trans) (19 trans women, 10 trans men), and non-binary (n=11) individuals using a prosody protocol. An objective acoustic analysis was performed to compare intonation parameters (upward/downward/flat intonation shift, general and final intonation shift, general fundamental frequency range, fundamental frequency variation index) between groups. In addition, a listening experiment was conducted, consisting of a cis and gender diverse listening panel (n=41). The listeners were asked to rate the femininity/masculinity of speech samples (n=57) using a visual analogue scale. Correlational analyses were used to examine the relationship between intonation parameters and femininity/masculinity ratings. Similarity was found in the intonation parameters of participants with a similar gender identity. In non-binary speakers, no significant differences in acoustic intonation parameters were found between these speakers and the cisgender speakers. In addition, no significant correlations were found between the acoustic intonation parameters and the femininity/masculinity ratings in the groups with cis men, cis women, and non-binary participants. However, moderate to strong significant correlations were found between acoustic intonation parameters and femininity/masculinity ratings in the trans participants. Intonation is a "speech marker" that distinguishes between groups with a different gender identity. No relationship was observed between intonation and femininity/masculinity ratings for cisgender and non-binary speakers. However, the significant relationship between these parameters for transgender participants (trans men and trans women) provides evidence for intonation exercises in gender affirming voice, speech, and communication training, and therefore contribute to evidence-based intonation training in transgender persons.

Recurrent Wavelet Fuzzy Neural Network-Based Reference Compensation Current Control Strategy for Shunt Active Power Filter

The usage of a shunt active power filter (SAPF) is one of the helpful means to mitigate the reactive power and harmonic current of a power grid. The compensation performance of the SAPF is related to the accuracy of the reference voltage extraction from the utility grid, the control stability of the DC-link voltage regulation, and the synchronization between the source voltage and the reference compensation current. To modify the performance of the SAPF for the harmonic compensation, the control strategy of the SAPF reference compensation current based on the recurrent wavelet fuzzy neural network (RWFNN) is proposed in this paper. There are three sections in the proposed control strategy, including the regulated fundamental positive-sequence extraction (section A), DC-link voltage regulation (section B), and calculation of reference compensation current (section C). By regulating the analysis mechanism with the variation of fundamental frequency in the section A, the accurate reference voltage would be obtained. The control stability for the regulation of the DC-link voltage can be accomplished by applying the RWFNN-based controller in the section B. With the synchronized reference voltage in the section A and the estimated control current in the section B, the reference compensation current can be correctly obtained in the section C. From the case studies with the real-time simulator produced by OPAL-RT Technologies Inc., the effectiveness of proposed control strategy for the SAPF reference compensation current can be verified.

Exploring the mechanics of fundamental frequency variation during phonation onset.

Fundamental frequency patterns during phonation onset have received renewed interest due to their promising application in objective classification of normal and pathological voices. However, the associated underlying mechanisms producing the wide array of patterns observed in different phonetic contexts are not yet fully understood. Herein, we employ theoretical and numerical analyses in an effort to elucidate the potential mechanisms driving opposing frequency patterns for initial/isolated vowels versus vowels preceded by voiceless consonants. Utilizing deterministic lumped-mass oscillator models of the vocal folds, we systematically explore the roles of collision and muscle activation in the dynamics of phonation onset. We find that an increasing trend in fundamental frequency, as observed for initial/isolated vowels, arises naturally through a progressive increase in system stiffness as collision intensifies as onset progresses, without the need for time-varying vocal fold tension or changes in aerodynamic loading. In contrast, reduction in cricothyroid muscle activation during onset is required to generate the decrease in fundamental frequency observed for vowels preceded by voiceless consonants. For such phonetic contexts, our analysis shows that the magnitude of reduction in the cricothyroid muscle activation and the activation level of the thyroarytenoid muscle are potential factors underlying observed differences in (relative) fundamental frequency between speakers with healthy and hyperfunctional voices. This work highlights the roles of sometimes competing laryngeal factors in producing the complex array of observed fundamental frequency patterns during phonation onset.

Prosodic features conveying doubt and trust

Research in affective prosody has shown that doubt (specifically, incredulity) is communicated through distinctive features like a slower speech rate, greater variability in fundamental frequency (F0), and a characteristic F0 pattern including an utterance final rise in F0. However, the opposite of doubt, trust (or belief), has not been examined as a prosodically distinct attitude. In response, this study explores the full range of doubt and trust native speakers of American English can express through prosody. In a web-based production experiment, we asked 30 participants to produce 12 utterances in neutral, trusting, and doubting prosody. A multinomial logistic regression analysis revealed that incredulous prosody differed significantly from neutral prosody primarily in its lower initial F0 and longer duration. Trust also differed from neutrality, with a significantly higher utterance initial F0 and less amplitude variability than was observed in neutral utterances. In a perception experiment, 115 participants listened to 36 tokens collected from the production experiment and were asked whether the talker expressed doubt or trust. Participants were generally accurate in their judgement of talker attitude, and acoustic variables of utterance-initial F0 and speech rate significantly predicted participant ratings of the talker's doubt or trust.