Irregular Pitch Research Articles

Acoustic cues to coda stop voicing contrasts in Australian English-speaking children.

While voicing contrasts in word-onset position are acquired relatively early, much less is known about how and when they are acquired in word-coda position, where accurate production of these contrasts is also critical for distinguishing words (e.g., dog vs. dock). This study examined how the acoustic cues to coda voicing contrasts are realized in the speech of 4-year-old Australian English-speaking children. The results showed that children used similar acoustic cues to those of adults, including longer vowel duration and more frequent voice bar for voiced stops, and longer closure and burst durations for voiceless stops along with more frequent irregular pitch periods. This suggests that 4-year-olds have acquired productive use of the acoustic cues to coda voicing contrasts, though implementations are not yet fully adult-like. The findings have implications for understanding the development of phonological contrasts in populations for whom these may be challenging, such as children with hearing loss.

Countermeasures to suppress polygonal deformation of machined hole with irregular pitch reamer

Reaming is a finishing process for expanding the pilot hole and improving the accuracy of roundness. In machining using regular teeth pitch reamer, a polygonal deformation phenomenon occurs in the machined hole due to self-excited vibration caused by time delay, which causes a problem of deterioration in product accuracy. In the previous studies, the authors clarify the generation mechanism of the polygonal deformation and examined the suppressive effect of the irregular tooth pitch reamers theoretically. The irregular tooth pitch reamers are available commercially and have been found to have improved roundness compared to regular tooth pitch reamers. However, the optimum design of the irregular pitch reamers has not yet been discussed. In this paper, the authors theoretically and experimentally discuss the optimum design of the irregular pitch reamers.

Development of the l = 2, m = 6 heliotron magnetic system with irregular helical coil pitch

Abstract In the present paper the numerical calculations of magnetic field properties of the l = 2, m = 6 heliotron with irregular helical coil pitch, the magnetic system model of which significantly differs from the previous model, is carried out. The new model has the doubled length helical coil section with reduced helical coil pitch (doubled length L-section). A vertical magnetic field compensation scheme, elaborated for the operating l = 2, m = 2 torsatron U-2M with the additional toroidal magnetic field coils, has been applied to compensate the vertical magnetic field of the l = 2, m = 6 heliotron with doubled length L-section. The calculation results show that due to the defined relation between the ampere-turns in the compensation and in the helical coils the developed l = 2, m = 6 heliotron magnetic system with irregular helical coil pitch can provide some increase of the magnetic surface existence region. Also the pinch of the closed magnetic surface region and of the outer boundary of the stochastic field line layer takes place within lengthened L-section.

Identifying a creak probability threshold for an irregular pitch period detection algorithm.

Irregular pitch periods (IPPs) are associated with grammatically, pragmatically, and clinically significant types of nonmodal phonation, but are challenging to identify. Automatic detection of IPPs is desirable because accurately hand-identifying IPPs is time-consuming and requires training. The authors evaluated an algorithm developed for creaky voice analysis to automatically identify IPPs in recordings of American English conversational speech. To determine a perceptually relevant threshold probability, frame-by-frame creak probabilities were compared to hand labels, yielding a threshold of approximately 0.02. These results indicate a generally good agreement between hand-labeled IPPs and automatic detection, calling for future work investigating effects of linguistic and prosodic context.

Toward the automatic detection of manually labeled irregular pitch periods

Toward the automatic detection of manually labeled irregular pitch periods

Toward the automatic detection of manually labeled irregular pitch periods

Irregular pitch periods (IPPs) occur in a wide variety of speech contexts and can support automatic speech recognition systems by signaling word boundaries, phrase endings, and certain prosodic contours. IPPs can also provide information about emotional content, dialect, and speaker identity. The ability to automatically detect IPPs is particularly useful because accurately identifying IPPs by hand is time-consuming and requires expertise. In this project, we use an algorithm developed for creaky voice analysis by Kane et al. (2013) incorporating features from Ishi et al. (2008) to automatically identify IPPs in recordings of speech from the American English Map Task database. Short-term power, intra-frame periodicity, inter-pulse similarity, subharmonic energy, and glottal pulse peakiness measures are input into an artificial neural network to generate frame-by-frame creak probabilities. To determine a perceptually relevant threshold probability, the creak probabilities are compared to IPPs hand-labeled by experienced raters. Preliminary results yielded an area under the receiver operating characteristic curve of 0.82. Thresholds above 0.1 produced very high specificity, but even lower thresholds yielded fairly high sensitivity and specificity. These results indicate generally good agreement between hand-labeled IPPs and automatic detection, calling for future work investigating effects of linguistic and prosodic context.

Analytical Modeling, Design and Performance Evaluation of Chatter-Free Milling Cutter With Alternating Pitch Variations

Machining efficiency could be increased and chatter vibrations could be suppressed by employing irregular pitch angles onto milling cutters. Applying variable pitch cutters could improve machining stability by disrupting the regenerative chatter mechanism and reducing cutting forces due to decreased nonlinear dynamic chip thicknesses. Previous studies on variable pitch cutters have been mainly investigating vibration suppression and dynamic modeling. There is a lack of efficient and practical variable pitch cutter design methods for practical industrial applications. An analytical method for designing milling cutters with alternating variable pitches has been proposed in this paper. In this method, a new variable, the generic sum of phase difference between the inner and outer waves, has been defined to model the machining dynamics and the stability of the variable pitch cutter. The phase difference value has then been investigated to obtain its generic optimal solution to the stability limit considering different cutting conditions. Based on this, the analytical variable pitch cutter design method is derived. The experimental results have manifested that, compared with uniform pitch cutter, the variable pitch cutter, designed using the proposed method, was able to achieve: 1) a critical stable axial depth of cut improvement of 126% under the desired spindle speed; 2) a cutting force reduction of 53%; 3) a decrease of 75% and 52% in Sq (the root mean square length of the scale limited surface) and Sz (the maximum height of the scale limited surface) of the machined surfaces, respectively. These significant improvements approved the superiority and robustness of the proposed design method for chatter suppression and may promote the application of variable pitch cutter technologies.

Research on Vocal Tic Symptom Detecting Using SVM/HMM

Vocal tic disorder represents a disease of making weird sounds without any reason. This disease must be found and cured in the early stage of the disease in order to prevent development to Tourette’s syndrome. In this paper, we introduce a machine learning based speech recognition technology to detect vocal tic disorder in the early stage. Vocal tic disorder has repetition but an irregular tic pitch that vary in each patient. To identify vocal tic disorder with these characteristics we used MFCC, a speech feature extraction method, and to generate a recognition model we used machine learning algorithms SVM and HMM. We confirmed an 88% recognition in the SVM algorithm and a 62% recognition in the HMM algorithm. This confirms that in identifying vocal tic disorders with repetition but irregular tic pitches SVM has a better recognition rate than HMM.

Individual differences in the signaling of prosodic structure by changes in voice quality

Earlier work has shown that speakers of American English often (although not always) produce irregular pitch periods (or other changes in voice quality) at prosodically significant locations, such as the onset of a new intonational phrase or a pitch-accented syllable, when those constituents begin with a [ + voiced] phonemic segment (Pierrehumbert & Talkin 1992). This tendency varied substantially across 5 speakers of FM-Radio-News-style speech (Dilley et al. 1996). Further work with speakers of a west-coast dialect (Garellek 2012) raised questions about the appearance of this cue at phrase onsets, when the phrase begins with a prosodically weak (lexically unstressed) syllable; this suggests that it occurs only for phrasally-strong (pitch accented) syllables, whether they occur in phrase-initial position or not. In contrast, extensive analysis of voice quality changes in a corpus of imitated utterances produced by speakers of a mid-western dialect (Cole & Shattuck-Hufnagel 2011) clearly shows a tendency for voice-quality changes at the onsets of prosodically weak syllables when they occur at the onsets of intonational phrases. This raises the possibility that individual speakers or dialects may differ in the likelihood of using changes in voice-quality to mark different types of prosodic events, such as phrase onsets vs pitch accents.

Irregular pitch periods as a feature cue in the developing speech of English-learning children

Changes in phonation patterns have long been studied as correlates of various linguistic elements, such as the occurrence of irregular pitch periods (IPPs) at significant locations in prosodic structure (in phrase-initial, phrase-final, and pitch accented contexts) and word-final voiceless stops, especially /t/. But less is known about the development of this phonation pattern in children [cf. Song et al., JASA, 131, 3036-50, 2012], particularly in toddlers between the ages of 2;6 and 3;6. The study of its course of acquisition may shed light on the mechanisms involved, since child vocal folds are very different physiologically from those of adults, and change strikingly during development. Monosyllabic target words from the Imbrie Corpus of speech from 10 toddlers 2 1/2 to 3 1/2 years old, ending in /t, d/ were examined for evidence of IPPs. Preliminary results based on three adult/child pairs suggest that both adults and children produce IPPs preceding coda /t/ about 50% of the time. But children produce fewer IPPs before coda /d/ than adults do (38% v 8%), suggesting (like earlier reports) that children are not simply imitating the cues produced by the adults around them. Data from additional adult/child pairs will be presented.

Design of irregular pitch end mills to attain robust suppression of regenerative chatter

Abstract This paper presents a design method of irregular pitch end mills, which ensures robust suppression of total regeneration in milling. Firstly, general formulation of irregular pitch angles is explained for simultaneous suppression of multi-mode regenerations. An index named “Regeneration Factor ( RF )” is introduced to quantify regenerative effect. Minimizing the mean value of the | RF | within a certain frequency range, suppression frequencies are distributed in the proposed method, resulting in robust suppression of regeneration regardless of chatter frequency and/or spindle speed variations. Experimental investigations verified significant robustness of the end mill with the proposed design against the spindle speed variation.

0516 An Experimental Study on Slotting of Inconel 718 Thin Sheet

Many difficult-to-cut materials such as Ni-base super alloy, titanium alloy, and austenite stainless steel which are used extensively in aerospace generally have high strength-to-weight ratios, high corrosion resistance, high strength retention ability at elevated temperatures, and low thermal conductivity. These characteristics can result in uneven tool wear and chatter vibration. Therefore, determining the appropriate end-milling conditions is more difficult for difficult-to-cut materials than for other materials. There has been much research on the high-speed milling of difficult-to-cut materials, and effective end-milling conditions, end-mill tool shapes, and processing methods have been reported. In addition, irregular pitch and lead end-mills with different helix angles have been developed by tool maker’s to reduce chatter vibration, making it easier to perform high-speed milling. However, there have been few reports of slotting information useful for determining appropriate end-milling conditions and processing methods for Ni-base super alloy. The aim of this study is to derive end-milling condition with high efficiency grooving process for Ni-base super alloy (Inconel 718) sheet. Effects of cutting parameters were examined from the view point of cutting resistance, tool tip maximum temperature and tool flank wear width. As a result from experiments, if the grooving process condition of axial depth of cut is smaller than other conditions on the same material removable rate value, it has been found that it is possible to reduce the tool tip maximum temperature and prolong the tool life.

S1330102 ロバストなびびり振動抑制を実現する工具設計理論の実験的検証

Chatter vibration in milling often results in poor surface finish and rapid tool wear, consequently limiting productivity. It is known that regenerative effect, which causes chatter vibration, can be suppressed by utilizing irregular pitch cutters. In order to attain robust regeneration suppression for arbitrary chatter frequency, the authors have proposed a novel design theory of irregular pitch cutters. The fundamental mechanism of it is the simultaneous suppression of multi-mode regenerations. In the present study, the effect on chatter suppression has been verified through a series of end milling experiment. Analytical and experimental results indicated that the chatter stability is effectively increased by utilizing the irregular pitch cutter designed by the proposed theory.

Timing matters: the processing of pitch relations.

The human central auditory system can automatically extract abstract regularities from a variant auditory input. To this end, temporarily separated events need to be related. This study tested whether the timing between events, falling either within or outside the temporal window of integration (~350 ms), impacts the extraction of abstract feature relations. We utilized tone pairs for which tones within but not across pairs revealed a constant pitch relation (e.g., pitch of second tone of a pair higher than pitch of first tone, while absolute pitch values varied across pairs). We measured the mismatch negativity (MMN; the brain’s error signal to auditory regularity violations) to second tones that rarely violated the pitch relation (e.g., pitch of second tone lower). A Short condition in which tone duration (90 ms) and stimulus onset asynchrony between the tones of a pair were short (110 ms) was compared to two conditions, where this onset asynchrony was long (510 ms). In the Long Gap condition, the tone durations were identical to Short (90 ms), but the silent interval was prolonged by 400 ms. In Long Tone, the duration of the first tone was prolonged by 400 ms, while the silent interval was comparable to Short (20 ms). Results show a frontocentral MMN of comparable amplitude in all conditions. Thus, abstract pitch relations can be extracted even when the within-pair timing exceeds the integration period. Source analyses indicate MMN generators in the supratemporal cortex. Interestingly, they were located more anterior in Long Gap than in Short and Long Tone. Moreover, frontal generator activity was found for Long Gap and Long Tone. Thus, the way in which the system automatically registers irregular abstract pitch relations depends on the timing of the events to be linked. Pending that the current MMN data mirror established abstract rule representations coding the regular pitch relation, neural processes building these templates vary with timing.

Stability analysis of milling with irregular pitch tools by the implicit subspace iteration method

Irregular pitch tools have been used since a long time ago to avoid chatter in milling processes. Optimal design of these mills was studied by some researchers. The method used is based in the frequency domain, and there were some practical examples showing that the process gives good results. Nevertheless, for high order lobes the method was not verified analytically, one of the difficulties being the large size of the matrices involved in the analysis. A recent method for obtaining stability diagrams is based in the use of implicit subspace iteration method, giving rise to much shorter calculation times than the already known discretized time domain methods. Use of this method allowed assessing the stability of processes with irregular pitch mills in both high and medium order lobes regions. The method of subspace iteration was compared with the more conventional semi-discretization method in low order lobes region, with good agreement. Afterwards, the stability of milling processes with irregular pitch tools designed after previous proposals was assessed in both medium and high order lobes regions. As a conclusion, in the examples analyzed the angles selection shows to be an optimal solution, although for high order lobes the regular pitch tools provides better stability. As a further research topic, other possible angle distributions to improve the behavior at low velocities should be analyzed.

An Indicative End-Milling Condition Decision Support System Using Data-Mining for Difficult-to-Cut Materials Based on Comparison with Irregular Pitch and Lead End-Mill and General Purpose End-Mill

Data-mining methods using hierarchical and non-hierarchical clustering are proposed that will help engineers determine appropriate end-milling conditions. We have constructed a system that uses clustering techniques and tool catalog data to support the determination of end-milling conditions for different types of difficult-to-cut materials such as austenitic stainless steel, Ni-base superalloy, and titanium alloy. Variable cluster analysis and the K-means method were used together to identify tool shape parameters that have a linear relationship with the end-milling conditions listed in the catalogs. The response surface method and significant tool shape parameters obtained by clustering were used to derive end-milling condition decision equations, which were used to determine the indicative end-milling conditions for each material. Comparison with the conditions recommended by toolmakers demonstrated that our proposed system can be used to determine the cutting speeds for various difficult-to-cut materials.

Objective Acoustic Quantification of Phonatory Dysfunction in Huntington's Disease

PurposeAlthough speech motor changes are reported as a common sign of Huntington’s disease (HD), the most prominent signs of voice dysfunction remain unknown. The aim of the current study was to explore specific changes in phonatory function in subjects with HD.Method34 subjects with HD and 34 age- and sex-matched healthy controls were examined. Participants performed sustained vowel phonation for subsequent analyses of airflow insufficiency, aperiodicity, irregular vibrations of vocal folds, signal perturbations, increased noise, and articulation deficiency. In total, 272 phonations were collected and 12 voice parameters were extracted. Subsequently, a predictive model was built to find the most salient patterns of voice disorders in HD. The results were also correlated with disease severity according to the Unified HD Rating Scale (UHDRS) motor score.ResultsSubjects with HD showed deterioration in all investigated phonatory functions. Irregular pitch fluctuations, sudden phonation interruption, increased noise, and misplacement of articulators were found to be most significant patterns of phonatory dysfunction in HD (p<0.001). The combination of these four dysphonia aspects contributed to the best classification performance of 94.1% (sensitivity: 95.1%; specificity: 93.2%) in the separation of HD patients from healthy participants. Our results further indicated stronger associations between sudden phonation interruption and voluntary components of the UHDRS (r = −0.48, p<0.01) and between misplacement of articulators and involuntary components of the UHDRS (r = 0.52, p<0.01).ConclusionsOur configuration of phonatory features can detect subtle voice abnormalities in subjects with HD. As impairment of phonatory function in HD was found to parallel increasing motor involvement, a qualitative description of voice dysfunction may be helpful to gain better insight into the pathophysiology of the vocal mechanism.

不等ピッチ/リードエンドミルによるびびり振動の抑制:安定限界に対する半径方向切込みの影響

不等ピッチ/リードエンドミルによるびびり振動の抑制:安定限界に対する半径方向切込みの影響

A Novel Design Method of Irregular Pitch Cutters to Attain Simultaneous Suppression of Multi-Mode Regenerations

It is known that regenerative effect, which causes self-excited chatter vibration, can be suppressed in many cases by utilizing irregular pitch tools. In order to suppress the regenerative effect sufficiently, a suitable combination of irregular pitch angles needs to be designed. Although the past researches proposed a basic idea to design irregular pitch angles for the regeneration suppression, they are only applicable to the suppression of single-mode regeneration. The present study proposes a novel design method of irregular pitch cutters, which ensures the simultaneous suppression of multi-mode regenerations. In order to quantify the regenerative effect, a new parameter called as the “Regeneration Factor” is proposed. The effect of pitch angles designed by the proposed method on chatter suppression is investigated analytically, and its validity is verified.

High Performance Titanium Milling at Low Cutting Speed

When machining titanium alloys the process stability limits increase very rapidly with reduced cutting speed. The stability rise is stronger than the drop of the cutting speed and it results in growth of removal rate. The increase in removal rate results in savings of machining costs. There is definite advantage in cutter geometry with irregular pitch for increasing the limit of stability. Use of PM HSS tools at low speeds for milling titanium alloys can be the most economical option. The paper introduces the concept of load intensity for assessing tool wear in milling.