Current Issue : October - December Volume : 2012 Issue Number : 4 Articles : 5 Articles
The aim of this paper is to improve beat-tracking for live guitar performances. Beat-tracking is a function to\r\nestimate musical measurements, for example musical tempo and phase. This method is critical to achieve a\r\nsynchronized ensemble performance such as musical robot accompaniment. Beat-tracking of a live guitar\r\nperformance has to deal with three challenges: tempo fluctuation, beat pattern complexity and environmental\r\nnoise. To cope with these problems, we devise an audiovisual integration method for beat-tracking. The auditory\r\nbeat features are estimated in terms of tactus (phase) and tempo (period) by Spectro-Temporal Pattern Matching\r\n(STPM), robust against stationary noise. The visual beat features are estimated by tracking the position of the hand\r\nrelative to the guitar using optical flow, mean shift and the Hough transform. Both estimated features are\r\nintegrated using a particle filter to aggregate the multimodal information based on a beat location model and a\r\nhand�s trajectory model. Experimental results confirm that our beat-tracking improves the F-measure by 8.9 points\r\non average over the Murata beat-tracking method, which uses STPM and rule-based beat detection. The results\r\nalso show that the system is capable of real-time processing with a suppressed number of particles while\r\npreserving the estimation accuracy. We demonstrate an ensemble with the humanoid HRP-2 that plays the\r\ntheremin with a human guitarist....
This article proposes a new acoustic model using decision trees (DTs) as replacements for Gaussian mixture models\r\n(GMM) to compute the observation likelihoods for a given hidden Markov model state in a speech recognition\r\nsystem. DTs have a number of advantageous properties, such as that they do not impose restrictions on the\r\nnumber or types of features, and that they automatically perform feature selection. This article explores and\r\nexploits DTs for the purpose of large vocabulary speech recognition. Equal and decoding questions have newly\r\nbeen introduced into DTs to directly model gender- and context-dependent acoustic space. Experimental results\r\nfor the 5k ARPA wall-street-journal task show that context information significantly improves the performance of\r\nDT-based acoustic models as expected. Context-dependent DT-based models are highly compact compared to\r\nconventional GMM-based acoustic models. This means that the proposed models have effective data-sharing\r\nacross various context classes....
The availability of haptic interfaces in music content processing offers interesting possibilities of performerinstrument\r\ninteraction for musical expression. These new musical instruments can precisely modulate the haptic\r\nfeedback, and map it to a sonic output, thus offering new artistic content creation possibilities. With this article, we\r\ninvestigate the use of a robotic arm as a bidirectional tangible interface for musical expression, actively modifying\r\nthe compliant control strategy to create a bind between gestural input and music output. The user can define\r\nrecursive modulations of music parameters by grasping and gradually refining periodic movements on a gravitycompensated\r\nrobot manipulator. The robot learns on-line the new desired trajectory, increasing its stiffness as the\r\nmodulation refinement proceeds. This article reports early results of an artistic performance that has been carried\r\nout with the collaboration of a musician, who played with the robot as part of his live stage setup....
This article studies a vital issue in wireless communications, which is the transmission of audio signals over wireless\r\nnetworks. It presents a novel interleaver scheme for protection against error bursts and reduction the packet loss\r\nof the audio signals. The proposed technique in the article is the chaotic interleaver; it is based on chaotic Baker\r\nmap. It is used as a randomizing data tool to improve the quality of the audio over the mobile communications\r\nchannels. A comparison study between the proposed chaotic interleaving scheme and the traditional block and\r\nconvolutional interleaving schemes for audio transmission over uncorrelated and correlated fading channels is\r\npresented. The simulation results show the superiority of the proposed chaotic interleaving scheme over the\r\ntraditional schemes. The simulation results also reveal that the proposed chaotic interleaver improves the quality of\r\nthe received audio signal. It improves the amount of the throughput over the wireless link through the packet loss\r\nreduction....
The perceptual attributes of timbre have inspired a considerable amount of multidisciplinary research, but because\r\nof the complexity of the phenomena, the approach has traditionally been confined to laboratory conditions, much\r\nto the detriment of its ecological validity. In this study, we present a purely bottom-up approach for mapping the\r\nconcepts that emerge from sound qualities. A social media (http://www.last.fm) is used to obtain a wide sample of\r\nverbal descriptions of music (in the form of tags) that go beyond the commonly studied concept of genre, and\r\nfrom this the underlying semantic structure of this sample is extracted. The structure that is thereby obtained is\r\nthen evaluated through a careful investigation of the acoustic features that characterize it. The results outline the\r\ndegree to which such structures in music (connected to affects, instrumentation and performance characteristics)\r\nhave particular timbral characteristics. Samples representing these semantic structures were then submitted to a\r\nsimilarity rating experiment to validate the findings. The outcome of this experiment strengthened the discovered\r\nlinks between the semantic structures and their perceived timbral qualities. The findings of both the computational\r\nand behavioural parts of the experiment imply that it is therefore possible to derive useful and meaningful\r\nstructures from free verbal descriptions of music, that transcend musical genres, and that such descriptions can be\r\nlinked to a set of acoustic features. This approach not only provides insights into the definition of timbre from an\r\necological perspective, but could also be implemented to develop applications in music information research that\r\norganize music collections according to both semantic and sound qualities....
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