The Experts below are selected from a list of 1734 Experts worldwide ranked by ideXlab platform
Sriram Srinivasan - One of the best experts on this subject based on the ideXlab platform.
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BIT-RATE REDUCTION STRATEGIES FOR NOISE SUPPRESSION WITH A REMOTE Wireless Microphone
2016Co-Authors: Ousman Sadiq, Sriram SrinivasanAbstract:In single-channel non-stationary noise reduction it is paramount that a good noise reference is available in a timely manner to maintain a high quality speech signal. Using a remote Wireless Microphone placed close to a noise source, a good estimate of the noise power spectral density (PSD) can be acquired. This estimate, however, needs to be transmitted to the primary Microphone for noise reduc-tion. As Wireless transmission is power intensive, it is desirable to reduce the bit-rate while maintaining good performance. In this pa-per, we propose techniques such as quantizing, frequency bin club-bing and intermittent PSD transmission to reduce the transmission bit-rate, and investigate their impact on performance. Index Terms — Speech enhancement, noise reduction, Wireless Microphone, ad-hoc sensor network. 1
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bit rate reduction strategies for noise suppression with a remote Wireless Microphone
International Conference on Acoustics Speech and Signal Processing, 2012Co-Authors: Nemanja Cvijanovic, Ousman Sadiq, Sriram SrinivasanAbstract:In single-channel non-stationary noise reduction it is paramount that a good noise reference is available in a timely manner to maintain a high quality speech signal. Using a remote Wireless Microphone placed close to a noise source, a good estimate of the noise power spectral density (PSD) can be acquired. This estimate, however, needs to be transmitted to the primary Microphone for noise reduction. As Wireless transmission is power intensive, it is desirable to reduce the bit-rate while maintaining good performance. In this paper, we propose techniques such as quantizing, frequency bin clubbing and intermittent PSD transmission to reduce the transmission bit-rate, and investigate their impact on performance.
Paulo Marques - One of the best experts on this subject based on the ideXlab platform.
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Cross-platform Demonstrator Combining Spectrum Sensing and a Geo-location Database
2016Co-Authors: Rogerio Dionisio, Jorge Ribeiro, José Ribeiro, Paulo MarquesAbstract:Abstract: After the digital switchover, a secondary access of the so-called TV White Spaces should not interfere with primary users, such as DVB-T systems and local Wireless Microphone devices. One consensual method for secondary spectrum users to avoid interference is to combine geo-location database with spectrum sensing. This paper describes an experimental platform that combines Wireless Microphone sensors with a web-based geo-location database access. Software defined radios and Internet technologies are the enabling tools in use. From test trials in a real scenario, the platform was capable to update a list of vacant channel from the geo-location database, using reliable information from blind sensing algorithms
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Combination of a geolocation database access with infrastructure sensing in TV bands
EURASIP Journal on Wireless Communications and Networking, 2014Co-Authors: Rogerio Dionisio, Jorge Ribeiro, Paulo Marques, Jonathan RodriguezAbstract:This paper describes the implementation and the technical specifications of a geolocation database assisted by a spectrum-monitoring outdoor network. The geolocation database is populated according to Electronic Communications Committee (ECC) report 186 methodology. The application programming interface (API) between the sensor network and the geolocation database implements an effective and secure connection to successfully gather sensing data and sends it to the geolocation database for post-processing. On the other hand, the testbed allows authorized TV white space devices to gain access to the services of the geolocation database, according to a draft implementation of Internet Engineering Task Force (IETF) Protocol to Access White Space (PAWS) Two experimental methodologies are available with the testbed: one focused on coexistence studies with commercial Wireless Microphones, when the testbed is used for sensing only, and another for demonstration purposes, when the testbed is also used to emulate Wireless Microphone signals. Overall, this hybrid approach is a promising solution for the effective use of TV white spaces and for the coexistence with digital TV broadcast signals, or dynamic incumbent systems, such as unregistered Wireless Microphones.
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Testbed for combination of local sensing with geolocation database in real environments
IEEE Wireless Communications, 2012Co-Authors: José C. Ribeiro, Jorge Ribeiro, Pedro Duarte, Rogerio Dionisio, Hugo Esteves, Jonathan Rodriguez, Paulo MarquesAbstract:This article describes an experimental testbed that combines Wireless Microphone sensors with a web-based terrestrial digital video broadcasting geolocation database and a program making and special events spectrumbooking platform. Software defined radio and Internet technologies are the enabling tools in use. The key sensing techniques are identified and implemented. Test trials in a real scenario have shown that the platform was able to receive information from a DVB-T geolocation database and a PMSE spectrum-booking platform, updating the list of vacant channels with blind sensing techniques. The proposed method has shown capabilities to protect primary users of interferences from secondary users of the spectrum.
Andries Ter Maat - One of the best experts on this subject based on the ideXlab platform.
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a minimum impact flexible tool to study vocal communication of small animals with precise individual level resolution
Methods in Ecology and Evolution, 2016Co-Authors: Lisa F Gill, Pietro Bruno Damelio, Nicolas M Adreani, Hannes Sagunsky, Manfred Gahr, Andries Ter MaatAbstract:1.To understand both proximate and ultimate factors shaping vocal communication, it is fundamental to obtain reliable information of participating individuals on different levels: Firstly, it is necessary to separate and assign the individuals’ vocalisations. Secondly, the precise timing of vocal events needs to be retained. Thirdly, vocal behaviour should be recorded from undisturbed animals in meaningful settings. A growing number of studies used animal-attached Microphones to tackle these issues, but the implications for the study species and the research question often receded into the background. Here we aim to initiate a discussion about the limitations, possible applications and the broader potential of such methods. 2.Using lightweight Wireless Microphone backpacks (0.75 g including customised leg-loop harness) combined with multi-channel recording equipment we captured vocal behaviour of small songbirds. We evaluated the effect of the devices at various levels, including an assessment of how vocal and locomotor activities were affected by initial device attachment and battery exchange. We compared our approach to existing studies and identified suitable research examples. 3.We acquired continuous vocalisation recordings of zebra finches, and unequivocally assigned them to interacting individuals, with system-based synchrony, irrespective of background noise. We found effects of initial backpack attachment and of battery replacement on vocal and locomotor activity, but they were minimised through the extended recording duration (ca. 16 days) that outlasted habituation effects (ca. 3 days). 4.This method provides the tools to integrate individual vocal communications into a group setting, while enabling animals to behave freely in undisturbed, structured and acoustically complex environments. By minimising the effects on the animals, the behaviour under study, and ultimately on the research question, this approach will revolutionize the ability to capture individual-level vocalisations in a variety of communication contexts, opening up many new opportunities to address novel research questions. This article is protected by copyright. All rights reserved.
Israel Cohen - One of the best experts on this subject based on the ideXlab platform.
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Performance analysis of a randomly spaced Wireless Microphone array
ICASSP IEEE International Conference on Acoustics Speech and Signal Processing - Proceedings, 2011Co-Authors: Shmulik Markovich-golan, Sharon Gannot, Israel CohenAbstract:A randomly distributed Microphone array is considered in this work. In many applications exact design of the array is impractical. The performance of these arrays, characterized by a large number of Microphones deployed in vast areas, cannot be analyzed by traditional deterministic methods. We therefore derive a novel statistical model for performance analysis of the MWF beamformer. We consider the scenario of one desired source and one interfering source arriving from the far-field and impinging on a uniformly distributed linear array. A theoretical model for the MMSE is developed and verified by simulations. The applicability of the proposed statistical model for speech signals is discussed.
Prasant Mohapatra - One of the best experts on this subject based on the ideXlab platform.
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hearing is believing detecting Wireless Microphone emulation attacks in white space
IEEE Transactions on Mobile Computing, 2013Co-Authors: Shaxun Chen, Kai Zeng, Prasant MohapatraAbstract:In cognitive radio networks, an attacker transmits signals mimicking the characteristics of primary signals, in order to prevent secondary users from transmitting. Such an attack is called primary user emulation (PUE) attack. TV towers and Wireless Microphones are two main types of primary users in white space. Existing work on PUE attack detection only focused on the first category. For the latter category, primary users are mobile and their transmission power is low. These properties introduce great challenges on PUE detection and existing methods are not applicable. In this paper, we propose a novel method to detect the emulation attack of Wireless Microphones. We exploit the relationship between RF signals and acoustic information to verify the existence of Wireless Microphones. The effectiveness of our approach is validated through real-world implementation. Extensive experiments show that our method achieves both false positive rate and false negative rate lower than 0.1 even in a noisy environment.
