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Rosa Alsina     Post Doctoral Researcher 
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Rosa Alsina published an article in December 2018.
Top co-authors See all
D. Altadill

67 shared publications

Observatori de l'Ebre; (OE) CSIC - Universitat Ramon Llull; Roquetes Spain

Joan Miquel Torta

40 shared publications

CSIC ‐ Universitat Ramon Llull Observatori de l'Ebre, (OE) Roquetes Spain

Marcos Hervás

18 shared publications

GTM-Grup de recerca en Tecnologies Mèdia; La Salle-Universitat Ramon Llull; Barcelona Spain

Ignacio Angulo

17 shared publications

Deusto Institute of Technology (DeustoTech), University of Deusto, Bilbao, Spain

Unai Hernandez-Jayo

14 shared publications

Facultad Ingeniería, Universidad de Deusto, Avda. Universidades, 24, 48007 Bilbao, Spain

Publication Record
Distribution of Articles published per year 
(2005 - 2018)
Total number of journals
published in
Publications See all
Article 0 Reads 0 Citations Construction of an Omnidirectional Parametric Loudspeaker Consisting in a Spherical Distribution of Ultrasound Transduce... Marc Arnela, Oriol Guasch, Patricia Sánchez-Martín, Joan Cam... Published: 07 December 2018
Sensors, doi: 10.3390/s18124317
DOI See at publisher website ABS Show/hide abstract
Omnidirectional sound sources are needed to perform a large variety of tests in acoustics. Typically, they consist of conventional speaker drivers arranged in a dodecahedron. However, the directivity of the speaker drivers sharpens with frequency, which induces an intense decrease of the sound pressure levels at the edges of the dodechaedron. In this work, the problem is mitigated by building an Omnidirectional Parametric Loudspeaker (OPL), which contains hundreds of small ultrasound transducers set on a sphere. Each transducer emits an ultrasonic carrier wave modulated by an audible signal. Thanks to nonlinear propagation, the air itself demodulates the signal bringing it back to the audible range. The construction of an OPL prototype is challenging. The structure has been built by 3D-printing a set of pieces that conform to the sphere. Each piece contains the exact location of the transducers, which are aligned in parallels to facilitate the structural assembly and the wiring. The performance of the OPL has been tested in an anechoic chamber. Measurements show that the OPL has a good omnidirectional behavior for most frequencies. It clearly improves the directivity of dodechaedral sources in the high frequency range, but performs worse at low frequencies.
Article 0 Reads 3 Citations An Anomalous Noise Events Detector for Dynamic Road Traffic Noise Mapping in Real-Life Urban and Suburban Environments Joan Claudi Socoró, Francesc Alías, Rosa Ma Alsina-Pagès Published: 12 October 2017
Sensors, doi: 10.3390/s17102323
DOI See at publisher website PubMed View at PubMed ABS Show/hide abstract
One of the main aspects affecting the quality of life of people living in urban and suburban areas is their continued exposure to high Road Traffic Noise (RTN) levels. Until now, noise measurements in cities have been performed by professionals, recording data in certain locations to build a noise map afterwards. However, the deployment of Wireless Acoustic Sensor Networks (WASN) has enabled automatic noise mapping in smart cities. In order to obtain a reliable picture of the RTN levels affecting citizens, Anomalous Noise Events (ANE) unrelated to road traffic should be removed from the noise map computation. To this aim, this paper introduces an Anomalous Noise Event Detector (ANED) designed to differentiate between RTN and ANE in real time within a predefined interval running on the distributed low-cost acoustic sensors of a WASN. The proposed ANED follows a two-class audio event detection and classification approach, instead of multi-class or one-class classification schemes, taking advantage of the collection of representative acoustic data in real-life environments. The experiments conducted within the DYNAMAP project, implemented on ARM-based acoustic sensors, show the feasibility of the proposal both in terms of computational cost and classification performance using standard Mel cepstral coefficients and Gaussian Mixture Models (GMM). The two-class GMM core classifier relatively improves the baseline universal GMM one-class classifier F1 measure by 18.7% and 31.8% for suburban and urban environments, respectively, within the 1-s integration interval. Nevertheless, according to the results, the classification performance of the current ANED implementation still has room for improvement.
Article 5 Reads 1 Citation An FPGA-Based WASN for Remote Real-Time Monitoring of Endangered Species: A Case Study on the Birdsong Recognition of Bo... Marcos Hervás, Rosa Ma Alsina-Pagès, Francesc Alías, Martí S... Published: 08 June 2017
Sensors, doi: 10.3390/s17061331
DOI See at publisher website PubMed View at PubMed ABS Show/hide abstract
Fast environmental variations due to climate change can cause mass decline or even extinctions of species, having a dramatic impact on the future of biodiversity. During the last decade, different approaches have been proposed to track and monitor endangered species, generally based on costly semi-automatic systems that require human supervision adding limitations in coverage and time. However, the recent emergence of Wireless Acoustic Sensor Networks (WASN) has allowed non-intrusive remote monitoring of endangered species in real time through the automatic identification of the sound they emit. In this work, an FPGA-based WASN centralized architecture is proposed and validated on a simulated operation environment. The feasibility of the architecture is evaluated in a case study designed to detect the threatened Botaurus stellaris among other 19 cohabiting birds species in The Parc Natural dels Aiguamolls de l’Empord
Article 0 Reads 2 Citations Towards Automatic Bird Detection: An Annotated and Segmented Acoustic Dataset of Seven Picidae Species Ester Vidaña-Vila, Joan Navarro, Rosa Ma Alsina-Pagès Published: 16 May 2017
Data, doi: 10.3390/data2020018
DOI See at publisher website ABS Show/hide abstract
Analysing behavioural patterns of bird species in a certain region enables researchers to recognize forthcoming changes in environment, ecology, and population. Ornithologists spend many hours observing and recording birds in their natural habitat to compare different audio samples and extract valuable insights. This manual process is typically undertaken by highly-experienced birders that identify every species and its associated type of sound. In recent years, some public repositories hosting labelled acoustic samples from different bird species have emerged, which has resulted in appealing datasets that computer scientists can use to test the accuracy of their machine learning algorithms and assist ornithologists in the time-consuming process of analyzing audio data. Current limitations in the performance of these algorithms come from the fact that the acoustic samples of these datasets combine fragments with only environmental noise and fragments with the bird sound (i.e., the computer confuses environmental sound with the bird sound). Therefore, the purpose of this paper is to release a dataset lasting more than 4984 s that contains differentiated samples of (1) bird sounds and (2) environmental sounds. This data descriptor releases the processed audio samples—originally obtained from the Xeno-Canto repository—from the known seven families of the Picidae species inhabiting the Iberian Peninsula that are good indicators of the habitat quality and have significant value from the environment conservation point of view.
Article 2 Reads 0 Citations Multiresolution acquisition scheme for the physical layer design of a direct sequence spread spectrum transequatorial HF... Rosa Ma Alsina-Pagès, Joan Claudi Socoró, Martí Salvador, Ma... Published: 11 May 2017
IET Communications, doi: 10.1049/iet-com.2016.1221
DOI See at publisher website
Article 1 Read 0 Citations Vertical and oblique ionospheric soundings performance comparison over the 12,760 km transequatorial HF link between Ant... Rosa Ma Alsina-Pagès, Marcos Hervás, David Altadill, J. Cald... Published: 29 April 2017
Radio Science, doi: 10.1002/2016rs006232
DOI See at publisher website