Open Access

ARTICLE

Lamia Bouafif¹, Noureddine Ellouze²
Sound & Vibration, Vol.52, No.6, pp. 2-10, 2018, DOI:10.32604/sv.2018.02410
Abstract Sound indexing and segmentation of digital documents especially in the internet and digital libraries are very useful to simplify and to accelerate the multimedia document retrieval. We can imagine that we can extract multimedia files not only by keywords but also by speech semantic contents. The main difficulty of this operation is the parameterization and modelling of the sound track and the discrimination of the speech, music and noise segments. In this paper, we will present a Speech/Music/Noise indexing interface designed for audio discrimination in multimedia documents. The program uses a statistical method based on More >

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1527

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ARTICLE

Jianguo Ma^{1, 2}, Changgeng Shuai^{1, 2}, Yan Li^{1, 2}
Sound & Vibration, Vol.52, No.6, pp. 11-17, 2018, DOI:10.32604/sv.2018.03893
Abstract The design and optimization of actuators are difficult and critical for the active-passive hybrid vibration control system. In this paper, an electromagnetic actuator model is established based on Ohm’s Law for magnetic circuit considering the leakage flux. The 600N electromagnetic actuators are designed and optimized based on ANSYS simulation according to the engineering request. Its transient characteristics are studied. The effects of different structural parameters on its output force are analyzed. The experimental results show that the structure parameters and output force characteristics of the designed electromagnetic actuators satisfy the practical requirement. More >

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1600

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ARTICLE

Xiaoli Zhong^{1, 2}, Wenying Guo¹, Jie Wang²
Sound & Vibration, Vol.52, No.6, pp. 18-22, 2018, DOI:10.32604/sv.2018.03900
Abstract Early reflection is an important component in an enclosed sound field. Due to the precedence effect, the early reflection may not be the dominant factor in sound source localization; however, it still has obvious influences on spatial position, loudness, timbre, and etc. Till now, there have sparse studies on evaluation of the audible threshold of early reflections with lacking of general and quantitative results. This work investigated the audible threshold of early reflection with a simplified sound field model under various experimental conditions including the combination of eight incidence angles and five time delays. Three-down-one-up… More >

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1568

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Xinggang Jiang^{1, 2}, Xianbin Zhu¹, Shanda Li³, Daxi Geng^{1, 2, *}, Deyuan Zhang^{1, 2}
Sound & Vibration, Vol.52, No.6, pp. 23-28, 2018, DOI:10.32604/sv.2018.03929
Abstract The sandwich transducer structure is comprised of three components along its main axis: the back metal cap, piezoelectric ceramic stack and the horn. The purpose of this work is to present a simplified method, referred as the equivalent length algorithm, to design the actuator parameters including each segment length and the resonance frequency f_s. The actuator length L and the propagation wavelength λ along its main axis satisfy the standing wave theory. So, define an equivalent length coefficient for each part of the actuator, and then the sandwich structure is regarded as a single material cylindrical rod… More >

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1591