Pitch Fluctuations Research Articles

Manufacture process and cabling optimization of Bi2212 CICC

The Bi2212 cable-in-conduit conductor (CICC) is a composite soft material and is sensitive to stress-strain and brittle breakage. The cabling tensions are critical parameters for the CICCs and have undergone trial production many times to achieve effective cable control. Unreasonable tension will cause circumferential and axial motion, resulting in deflection bending, rotation fluctuations, and wire slip. This study investigated the manufacturing process of the Bi2212 CICC, optimizing the cable twisting process and reducing manufacturing consumption and damage. Additionally, optimized tensions of the Bi2212 CICCs during the cabling process, focusing on pay-off tension, rotation speeds, and traction tensions were presented. Finally, the results are tested and verified in the factory to examine the wire jumpers, serpentine bending, and pitch fluctuations. This research provides useful references for future cable fabrication of the HTS CICCs.

Comparison of aerodynamic and aeroacoustic characteristics of fixed-pitch and variable-pitch rotors

This research conducts a comparative analysis of the aerodynamic and aeroacoustic characteristics of fixed-pitch and variable-pitch controlled multirotors [i.e., revolution per minute (RPM) and collective pitch control]. The study encompasses single-, twin-, and quad-rotor configurations under hovering flight conditions. The unsteady blade motion is modeled as a function of RPM and pitch, fluctuating with frequency and amplitude. To comprehensively account for wake interaction effects, a free-wake vortex lattice method combined with acoustic analogy is utilized. The findings reveal that unsteady blade motion and wake interaction effects cause fluctuations in thrust and tip vortex trajectory. The thrust and tip vortex behavior exhibited greater instability in response to RPM fluctuations than to pitch fluctuations. Consequently, the axial unsteady loading noise was more pronounced under RPM fluctuations compared to pitch fluctuations. In both twin- and quad-rotor configurations, the wake interaction significantly influenced the characteristics of thrust and tip vortex behavior. In addition, spectral analysis demonstrated that the frequencies of unsteady blade motion and wake interaction determine the frequencies of thrust and tip vortex fluctuations as well as unsteady loading noise.

The Vocal Flutter of Multiple System Atrophy: A Parkinsonian-Type Phenomenon?

Early features of multiple system atrophy (MSA) are similar to those in Parkinson's disease (PD), which can challenge differential diagnosis. Identifying clinical markers that help distinguish MSA from forms of parkinsonism is essential to promptly implement the most appropriate management plan. In the context of a thorough neurological evaluation, the presence of a vocal flutter might be considered a potential feature of MSA-parkinsonian type (MSA-P). This case series describes clinical histories of 3 individuals with MSA-P. In each case, vocal flutter was detected during neurological and motor speech evaluations. It seemed to be a concomitant feature with the constellation of other signs and symptoms that led to the clinical diagnosis. The vocal flutter may be described as pitch and loudness fluctuations during phonation. Different from a vocal tremor, the flutter phenomenon has higher oscillation frequencies. The neuropathological underpinnings of vocal flutter may be related to generalized laryngeal dysfunction that is commonly described in MSA-P. Vocal flutter may be a unique speech feature in some individuals who have MSA-P. Future studies using perceptual and acoustic measures of speech are warranted to quantify these observations and directly compare to other MSA variants, PD, and a control group.

Deep Learning for the Recognition of Human Speech

Abstract—Humans primarily communicate through speech, and language is their main means of doing so. Emotion is crucial to social connection. Knowing how to recognise the emotions in a speech is important and challenging given that we are dealing with human-machine interaction. Depending on the mood a person is going through, they will express themselves differently. When someone expresses their emotions, each one has a distinctive energy, pitch, and tone fluctuation that is categorised according to the situation. The identification of spoken emotions is thus a future goal for computer vision. The objective of our project is to develop intelligent speechthat utilises a convolutional neural network to recognise emotions. which uses a variety of modules for emotion recognition and classifier. Keywords— Human speech, Emotion, recognition of speech, GMM, Mel-Frequency-Cepstrum Coefficient (MFCC), linear prediction Cepstral coefficients (LPCC) , (LSTM)

Watt Linkage–Based Legged Deployable Landing Mechanism for Reusable Launch Vehicle: Principle, Prototype Design, and Experimental Validation

The reusable launch vehicle (RLV) presents a new avenue for reducing cost of space transportation. The landing mechanism, which provides landing support and impact absorption, is a vital component of the RLV at final stage of recovery. This study proposes a novel legged deployable landing mechanism (LDLM) for RLV. The Watt-II six-bar mechanism is adopted to obtain the preferred configuration via the application of the linkage variation approach. To endow the proposed LDLM with advantages of large landing support region, lightweight, and reasonable linkage internal forces, a multi-objective optimization paradigm is developed. Furthermore, the optimal scale parameters for guiding the LDLM prototype design is obtained numerically using the non-dominated sorting genetic algorithm-II (NSGA-II) evolutionary algorithm. A fully-functional scaled RLV prototype is developed by integrating the gravity-governed deploying scheme to facilitate unfolding action to avoid full-range actuation, a dual-backup locking mechanism to enhance reliability of structure stiffening as fully deployed, and a shock absorber (SA) with multistage honeycomb to offer reliable shock absorbing performance. The experimental results demonstrate that the proposed LDLM is capable of providing rapid and smooth deployment (duration less than 1.5 s) with mild posture disturbance to the cabin (yaw and pitch fluctuations less than 6°). In addition, it provides satisfactory impact attenuation (acceleration peak less than 10g) in the 0.2 m freefall test, which makes the proposed LDLM a potential alternative for developing future RLV archetype.

한국어 음운구 억양 유형의 변별적 특성과 변이 조건에 대한 연구: 음절 수와 분절음 종류의 영향을 중심으로*

This study identifies distinguishing features and variability of intonation patterns in Korean phonological phrases. Syllable count and segmental content, which are phonological conditions, of the intonation of phonological phrases were examined. Based on the four syllables, the intonation of a phonological phrase can be set to LHLH as the basic form, and syllable count acts as a condition for making a variation. The “3 syllables or less condition” changes the intonation from a curved line to a straight line. Variation occurs in pitch bandwidth and fluctuation according to segmental content. The first segment affects the phonological phrase formation bandwidth, and the following segment affects the pitch fluctuation. If the first segment has [+aspirate], [+tense], [+continuant], the intonation is formed in the high band, otherwise, it is formed in the low band. If the second or after segment in the intonation realized in the high band has [–aspirate], [–tense], [–continuant], the pitch is lowered to the lowest level of the low bandwidth. In the intonation realized in the low band, [+aspirate], [+tense], [+continuant] is blocked by the second descent of LHLH.

Active Disturbance Rejection Control for Wind Turbine Fatigue Load

With the participation of wind power in grid frequency modulation, the fatigue load of the wind turbine increases accordingly. A new control method that considers both fatigue load and output power of wind turbine (WT) is proposed in this paper. A linear active disturbance rejection control (LADRC) is designed and applied for the pitch angle in the wind turbine load reduction control. The particle swarm optimization (PSO) algorithm is used to optimize the parameters of the wind turbine controller, and the total variation of the wind turbine shaft torque and tower bending moment is added to construct a new objective function to further reduce the fatigue load of the wind turbine. The design-optimized controller is validated on a 5 MW wind turbine in SimWindFarm. The simulation results show that the LADRC controller can accurately track the reference power of the wind turbine, reduce the pitch angle fluctuation of the wind turbine, reduce the fatigue load of the wind turbine, and improve the service life of the wind turbine.

Detection of pitch errors in well-known songs.

We examined pitch-error detection in well-known songs sung with or without meaningful lyrics. In Experiment 1, adults heard the initial phrase of familiar songs sung with lyrics or repeating syllables (la) and judged whether they heard an out-of-tune note. Half of the renditions had a single pitch error (50 or 100 cents); half were in tune. Listeners were poorer at pitch-error detection in songs with lyrics. In Experiment 2, within-note pitch fluctuations in the same performances were eliminated by auto-tuning. Again, pitch-error detection was worse for renditions with lyrics (50 cents), suggesting adverse effects of semantic processing. In Experiment 3, songs were sung with repeating syllables or scat syllables to ascertain the role of phonetic variability. Performance was poorer for scat than for repeating syllables, indicating adverse effects of phonetic variability, but overall performance exceeded Experiment 1. In Experiment 4, listeners evaluated songs in all styles (repeating syllables, scat, lyrics) within the same session. Performance was best with repeating syllables (50 cents) and did not differ between scat or lyric versions. In short, tracking the pitches of highly familiar songs was impaired by the presence of words, an impairment stemming primarily from phonetic variability rather than interference from semantic processing.

Early Cochlear Implantation Allows Deaf Children to Control Voice Pitch and Loudness independently.

Congenitally deaf children with a cochlear implant (CI) improve their speech production intelligibility, but their prosody, including stress and intonation produced by voice pitch and loudness changes, often differs from normal hearing people, which affects their fluent oral communication. This study is aimed to clarify abnormal characteristics of voice pitch and loudness control in CI recipients using a newly developed visually guided pitch change task. We included 13 normal hearing volunteers (NH group) and 17 congenitally deaf CI users who showed good speech intelligibility. The 17 CI users were divided into Early-CI and Late-CI groups, based on their age at implantation of 2.5 years. Using the visually guided pitch change task and acoustic voice analysis of sustained vowels, we assessed their vocal skills to maintain constant pitch and loudness and intentionally change the voice pitch independent from loudness. At the time of examination, the mean age was 24.1, 12.7, and 18.9 years in the NH, Early-CI, and Late-CI groups. During constant vowel production, Early-CI and Late-CI groups showed more significant fluctuations in pitch and loudness than the NH group. However, when focusing on intentionally changing only the pitch of the voice, the Early-CI group was significantly better than the Late-CI group and comparable to the NH group in terms of their ability to change vocal pitch independently from loudness. Among congenitally deaf patients, age at implantation was associated with the development of voice skills to control voice pitch and loudness separately, which may influence their fluent prosody production.

The influence of the position and shape geometry of the counter-conical motion transmitter pin on the pitch fluctuation of the spiroid worm machined with adjusted shaft

The difference between the mathematical defined shape of the conical helicoid surface and the operating surface of the spiroid worm produced with axis adjustment on a thread grinding machine results – among other things –in thread pitch fluctuation. During the manufacturing of conical helicoid surfaces the transmission of the rotation from the main spindle to the worm shaft can be realised by a driving pin and an adjusted lathe dog. This article deals with the examination of the fluctuation of the thread pitch parameter occurring when using a counter-conical drive pin. The fluctuation is described here as a function of the position and the shape geometry of the drive pin.

Multi-Scale Spatial and Temporal Speech Associations to Swallowing for Dysphagia Screening

Dysphagia is a common symptom of many neurological diseases. It often occurs in older adults and increases the risk of aspiration pneumonia. Existing diagnosis systems of dysphagia are invasive or require patients to swallow liquids, which are costly and harmful to the patients. In this work, we propose an early screening system of dysphagia based on two kinds of throat signals, i.e., vowels and sentences. Based on the vowels, two new categories of speech features are developed: PET (pitch/energy trajectory) and FS-Conts (full spectrogram contours). The PET feature set focuses on the prominent resonance energy of speech to track the pitch and energy fluctuations. It can reflect the stability of vocal cords in the speech generation process. The FS-Conts feature set is proposed to emphasize the spatial details of formants based on three-dimensional contours. Concerning the sentences, three categories of speech features are proposed, called LSSDL (log symmetric spectral difference level), C-coes (crucial energy coefficients), and LDF (local dynamic features). The three features explore the speech representations of dysphagia from global variations to local associations. The LSSDL feature set is designed to highlight the global spectral differences in the interested frequency region. The C-coes and LDF feature sets locate local speech differences in specific frequency regions and time duration. In addition, a new feature selection algorithm is developed based on a newly designed precise matching analysis technique to search for distinguishing features. In the classification experiments, the SVM classifier is adopted and the dysphagia detection accuracy reaches 95.07%. The comparative experiments are conducted. The results indicate that our system performs better than the existing methods.

From Single to Multi Mode Lasing: The role of materials revealed in optical simulations

ABSTRACT The comparative study of thin film Cholesteric Liquid Crystal (CLC) lasers made from different materials and optically pumped by an external solid state laser reveals a striking dependence of lasing behaviour (ranging from single mode at the edge of the selective reflection band to multimode lasing) on the morphology and microstructure of CLC films. The materials studied belong to two groups: low molar mass liquid crystals and polymers. It is shown that the orientation of individual chiral domains and fluctuations in helical pitch contribute significantly to the type of lasing displayed by the material. Different ways of preparing CLC cells that lead to predominantly one type of lasing are discussed. The importance of variations of the helical pitch and domain orientation in producing single and multimode lasing is justified by optical simulations (4x4 matrix method) of lasing in multilayered samples.

Stable jump control for the wheel-legged robot based on TMS-DIP model

PurposeThe purpose of this paper is to propose a novel jump control method based on Two Mass Spring Damp Inverted Pendulum (TMS-DIP) model, which makes the third generation of hydraulic driven wheel-legged robot prototype (WLR-3P) achieve stable jumping.Design/methodology/approachFirst, according to the configuration of the WLR, a TMS-DIP model is proposed to simplify the dynamic model of the robot. Then the jumping process is divided into four stages: thrust, ascent, descent and compression, and each stage is modeled and solved independently based on TMS-DIP model. Through WLR-3P kinematics, the trajectory of the upper and lower centroids of the TMS-DIP model can be mapped to the joint space of the robot. The corresponding control strategies are proposed for jumping height, landing buffer, jumping attitude and robotic balance, so as to realize the stable jump control of the WLR.FindingsThe TMS-DIP model proposed in this paper can simplify the WLR dynamic model and provide a simple and effective tool for the jumping trajectory planning of the robot. The proposed approach is suitable for hydraulic WLR jumping control. The performance of the proposed wheel-legged jump method was verified by experiments on WLR-3P.Originality/valueThis work provides an effective model (TMS-DIP) for the jump control of WLR-3P. The results showed that the number of landing shock (twice) and the pitch angle fluctuation range (0.44 rad) of center of mass of the jump control method based on TMS-DIP model are smaller than those based on spring-loaded inverted pendulum model. Therefore, the TMS-DIP model makes the jumping process of WLR more stable and gentler.

Coupled analysis of a 10 MW multi-body floating offshore wind turbine subjected to tendon failures

In this study dynamic responses of a 10 MW offshore wind turbine supported by a multi-body floating platform that consists of a wide cylindrical platform and a cylindrical ballast body suspended by six tendons are analyzed and predicted for different tendon breakage scenarios. A newly-developed and validated fully coupled numerical tool (F2A) based on AQWA and FAST is used to perform aero-hydro-servo-elastic analysis of the floating offshore wind turbine (FOWT). The results indicate that the dynamic behavior of the platform is heavily influenced by the state of tendons health. Roll and yaw motions of the platform under a tendon breakage are found to experience 6 times magnitude amplification of the typical responses, depending on the specific environmental conditions considered. Moreover, the peak tension in the tendon adjacent to the broken tendon experienced an increase of 165% in magnitude. The collective-pitch mode of the platform and wave excitation that are the main contributors to the surge and pitch fluctuations are slightly affected by tendon breakages. The influence of tendon breakages is found to be only significant on the local-pitch and coupled-pitch modes of the platform. In addition, multifractal spectra of the platform accelerations under different tendon failure scenarios show distinct fractal characteristics that can effectively identify and diagnose tendon failures, which is essential to the development of a structural health monitoring system of FOWTs.

Proposed solution to eliminate pitch fluctuation in case of conical screw surface machining by apex adjustment

In case of conical worm production by conventional thread grinder, the fluctuation in angular velocity causes thread error. One possible way to eliminate the pitch error at the conical screw surface machining by shaft displacement is to design a drive pin that provides a constant pitch. In the course of our research, the examination of the machining of the conical worm surfaces by apex adjustment to eliminate the pitch fluctuation problem was carried out as a generalization of studies simulated with trigonometric relations in a particular case. The investigation was continued in a constructive geometric way with the aim of exploring universal mathematical relations in explicit forms in the mathematical kinematic model instead of the point series of the driver pin creator curve calculated in a given occurrence. The developed method makes exact design of the correct threading possible as a function of angular rotation in motion transfer under the given technology conditions, and thus expands the mathematical toolbar for innovative engineering design. Here we introduce the constructive geometric path supported by the algebraic toolbar, which also required affine and projective geometric relations in developing a solution that meets freely chosen expectations.

음성신호의 Jitter 성분의 장시간 변화에 관한 통계적 분석*

In this study, a method for measuring the jitter component in continuous speech is presented. In the conventional jitter measurement method, pitch variabilities are commonly measured from the sustained vowels. In the case of continuous speech, such as a spoken sentence, distortion occurs with the existing measurement method owing to the influence of prosody information according to the sentence. Therefore, we propose a method to reduce the pitch fluctuations of prosody information in continuous speech. To remove this pitch fluctuation component, a curve representing the fluctuation is obtained via polynomial interpolation for the pitch track in the analysis interval, and the shift is removed according to the curve. Subsequently, the variability of the pitch frequency is obtained by a method of measuring jitter from the trajectory of the pitch from which the shift is removed. To measure the effects of the proposed method, parameter values before and after the operations are compared using samples from the Kay Pentax MEEI database. The statistical analysis of the experimental results showed that jitter components from the continuous speech can be measured effectively by proposed method and the values are comparable to the parameters of sustained vowel from the same speaker.

Pitch Control Scheme for Rapid Active Power Control of a PMSG-Based Wind Power Plant

This article proposes a pitch control scheme for rapid active power control of a permanent-magnet synchronous generator (PMSG)-based wind power plant (WPP). To minimize the pitch angle fluctuation, the target pitch angle is determined by using an analytical calculation, not a conventional proportional-integral controller. When an active power control signal is received from the grid operator, the WPP controller sends the reference power to each PMSG. The proposed pitch control scheme obtains the reference power coefficient (C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">P</sub> ) from the reference and available powers; then, it analytically determines a target pitch angle to meet the reference C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">P</sub> from the C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">P</sub> function. To reduce the rotor speed fluctuation, the target pitch angle is determined to maintain the optimum lambda during the active power control. The performance of the scheme was investigated using an ElectroMagnetic Transient Program - Revised Version (EMTP-RV) simulator. Test results indicate that the scheme successfully reduces the fluctuations of the pitch angle and rotor speed during the active power reduction while satisfying the active power control requirement.

Polyphonic pitch tracking with deep layered learning.

This article presents a polyphonic pitch tracking system that is able to extract both framewise and note-based estimates from audio. The system uses several artificial neural networks trained individually in a deep layered learning setup. First, cascading networks are applied to a spectrogram for framewise fundamental frequency (f0) estimation. A sparse receptive field is learned by the first network and then used as a filter kernel for parameter sharing throughout the system. The f0 activations are connected across time to extract pitch contours. These contours define a framework within which subsequent networks perform onset and offset detection, operating across both time and smaller pitch fluctuations at the same time. As input, the networks use, e.g., variations of latent representations from the f0 estimation network. Finally, erroneous tentative notes are removed one by one in an iterative procedure that allows a network to classify notes within a correct context. The system was evaluated on four public test sets: MAPS, Bach10, TRIOS, and the MIREX Woodwind quintet and achieved state-of-the-art results for all four datasets. It performs well across all subtasks f0, pitched onset, and pitched offset tracking.

Experimental verification of cutting blade path for reduction of pitch angle fluctuation in a spinach automatic harvester

Experimental verification of cutting blade path for reduction of pitch angle fluctuation in a spinach automatic harvester

Online Audio-Visual Source Association for Chamber Music Performances

In audio-visual recordings of music performances, visual cues from instrument players exhibit good temporal correspondence with the audio signals and the music content. These correspondences provide useful information for estimating source associations, i.e., for identifying the affiliation between players and sound sources or score parts. In this paper, we propose a computational system that models audio-visual correspondences to achieve source association for Western chamber music ensembles including strings, woodwind, and brass instruments. Through its three modules, the system models three typical types of correspondences between 1) body motion (e.g., bowing for string instruments and sliding for trombone) and note onsets, 2) finger motion (e.g., fingering for most woodwind and brass instruments) and note onsets, and 3) vibrato hand motion (e.g., fingering hand rolling for string instruments) and pitch fluctuations. Although the three modules are designed for estimating associations for different instruments, the overall system provides a universal framework for all common melodic instruments in Western chamber ensembles. The framework automatically and adaptively integrates the three modules, without requiring prior knowledge of the instrument types. The system operates in an online fashion, i.e., associations are updated as the audio-visual stream progresses. We evaluate the system on ensembles with different instruments and polyphony, ranging from duets to quintets. Results demonstrate that association accuracy increases as the duration of video excerpts increases. For string quintets, the accuracy is over 90% from just a 5-second video excerpt, while for woodwind, brass, and mixed-instrument quintets, a similar accuracy can be reached after processing 30 seconds of video. The result of the proposed framework is promising and enables novel applications such as interactive audio-visual music editing and auto-whirling camera in concerts.