An extension to the filtered-x LMS algorithm with logarithmic transformation

© 2015 IEEE. Active control of impulsive noise has been of increasing interest due to high impact of such noise on humans. The algorithm with logarithmic transformation, developed by Wu, et al. has been found particularly interesting. In this paper this idea is continued, and an extension to this algorithm is proposed to improve its convergence properties and allow for successful control if the noise has also another type of noise together with the impulses. A number of simulations are performed to validate the algorithm and compare it with algorithms leading in the literature. Additionally to simulated benchmark impulsive noises, real recordings are considered, which bring another insight into efficiency of the algorithms

Effects of errorless learning on the acquisition of velopharyngeal movement control

Session 1pSC - Speech Communication: Cross-Linguistic Studies of Speech Sound Learning of the Languages of Hong Kong (Poster Session)The implicit motor learning literature suggests a benefit for learning if errors are minimized during practice. This study investigated whether the same principle holds for learning velopharyngeal movement control. Normal speaking participants learned to produce hypernasal speech in either an errorless learning condition (in which the possibility for errors was limited) or an errorful learning condition (in which the possibility for errors was not limited). Nasality level of the participants’ speech was measured by nasometer and reflected by nasalance scores (in %). Errorless learners practiced producing hypernasal speech with a threshold nasalance score of 10% at the beginning, which gradually increased to a threshold of 50% at the end. The same set of threshold targets were presented to errorful learners but in a reversed order. Errors were defined by the proportion of speech with a nasalance score below the threshold. The results showed that, relative to errorful learners, errorless learners displayed fewer errors (50.7% vs. 17.7%) and a higher mean nasalance score (31.3% vs. 46.7%) during the acquisition phase. Furthermore, errorless learners outperformed errorful learners in both retention and novel transfer tests. Acknowledgment: Supported by The University of Hong Kong Strategic Research Theme for Sciences of Learning © 2012 Acoustical Society of Americapublished_or_final_versio

Shaping zones of quiet in a large enclosure generated by an active noise control system

[EN] Performance of an Active Noise Control (ANC) system strongly depends on sensors and actuators spatial arrangement. It determines both achieved Noise Reduction (NR) levels and spatial distribution of obtained zones of quiet, making it an essential problem. However, if the acoustic field in the enclosure can be appropriately modelled, then optimization algorithms can be employed to find efficient configuration of the ANC system, enhancing its performance according to a formulated cost function and constraints. This paper proposes a complete method for enhancing NR levels and shaping zones of quiet generated with an ANC system by optimization of sensors and actuators arrangement. A Memetic Algorithm (MA) is utilized. The MA itself and its proposed operators are described. The optimization problem formulation is derived and discussed. As a control algorithm, Distributed Multiple Error Filtered-x Least Mean Square (DMEFxLMS) is used. Extensive simulation results are presented for an exemplary real enclosure. The model of the acoustic environment has been obtained by real-world experiments, resulting in identification of 36864 acoustic responses in total. Practically feasible cost function and constraints are evaluated. Advantages and limits of the method are pointed out and discussed.The research reported in this paper has been supported by the National Science Centre, Poland, decision no. DEC-2017/25/B/ST7/02236, and by EU together with Spanish Government under Grant TEC2015-67387-C4-1-R b(MINECO/FEDER).Wrona, S.; Diego Antón, MD.; Pawelczyk, M. (2018). Shaping zones of quiet in a large enclosure generated by an active noise control system. Control Engineering Practice. 80:1-16. https://doi.org/10.1016/j.conengprac.2018.08.004S1168

Noise source identification on large generator units

Abstract unavailable please refer to PD

Vocal fold vibratory and acoustic features in fatigued Karaoke singers

Session 3aMU - Musical Acoustics and Speech Communication: Singing Voice in Asian CulturesKaraoke is a popular singing entertainment particularly in Asia and is gaining more popularity in the rest of world. In Karaoke, an amateur singer sings with the background music and video (usually guided by the lyric captions on the video screen) played by Karaoke machine, using a microphone and an amplification system. As the Karaoke singers usually have no formal training, they may be more vulnerable to vocal fatigue as they may overuse and/or misuse their voices in the intensive and extensive singing activities. It is unclear whether vocal fatigue is accompanied by any vibration pattern or physiological changes of vocal folds. In this study, 20 participants aged from 18 to 23 years with normal voice were recruited to participate in an prolonged singing task, which induced vocal fatigue. High speed laryngscopic imaging and acoustic signals were recorded before and after the singing task. Images of /i/ phonation were quantitatively analyzed using the High Speed Video Processing (HSVP) program (Yiu, et al. 2010). It was found that the glottis became relatively narrower following fatigue, while the acoustic signals were not sensitive to measure change following fatigue. © 2012 Acoustical Society of Americapublished_or_final_versio

Technological Innovations Culminating in the American Symphonic Organ, 1880-1920

The middle nineteenth century saw the rise of the Romantic Era and, with it, a change in the prevailing musical aesthetics. Composers expanded musical forms and pioneered new ones with the goal of expressing intense emotions. With the expansion in musical forms came an expansion in the size and tonal variety of the symphony orchestra. Audiences welcomed the aesthetic changes of Romanticism, and their preference for a warmer, richer sound carried over to the organ world. Dispositions of instruments of the early nineteenth century lacked the variety in tone and power to adequately produce the sound desired by performers and listeners. As organbuilders attempted to meet the demands of players and audiences, it became clear that the organ’s mechanism could not sustain the desired aesthetic. European organbuilders introduced a number of technological advances to try and remedy this problem, but it was left to American organbuilders to pioneer new methods of construction that finally met the demands of performers and audiences: the American Symphonic Organ. The entire existence of the mature American Symphonic Organ of the 1920s relied on the technological advances of the late nineteenth and early twentieth centuries that enabled organbuilders to produce the dark tone colors and orchestral imitative voices associated with high wind pressures in instruments exhibiting superb musical flexibility. Defining a specific aesthetic end as the basis for discussion, this document examines the developments of various components of the organ’s mechanism in the hands of American organbuilders between the years 1880 and 1920 that each played a requisite role in the formation of the American Symphonic Organ, including developments in actions, electromagnets, swell mechanisms, key contacts, console designs, combination actions, and blowers. In every area of the instrument’s development, organbuilders strove to reduce the strain on the performer through the introduction of electricity and a steady, copious wind supply to enable quick, reliable manipulation of the tonal resources. The last decade has seen a resurgence of interest in the organs of the early twentieth century and their associated tonal disposition after years of neglect. Just as changes in aesthetic preferences brought about the American Symphonic Organ, changes in the middle of the twentieth century brought about its fall from favor. Many of the organs of the early 1900s that were not entirely discarded were substantially altered to meet the demands of a new generation of musicians and listeners that desired a decisively brighter tone inspired by instruments of previous centuries. The pendulum swung from one extreme of robust tone and color in the American Symphonic Organ of 1920 to one of extreme brilliance and clarity in the Neo-Baroque organs of the 1960s. Since the 1960s, the pendulum has swung back toward the center, and both organists and organbuilders are finding a new balance between the extremes outlined above. With a renewed interest in the tonal philosophy espoused in the early twentieth century, numerous instruments from this time period have recently been restored, rebuilt, or rescued from storage and are finding a home in churches and concert halls where they are stirring the hearts and minds of listeners as they did a century ago. With this renewed interest in the American Symphonic Organ, this document seeks to trace a history of technological progress that guided the instrument from its state in 1880 to a golden age in the 1920s

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博士（工学）佐賀大