Alfonso Ortega

Alfonso Ortega

orcid

Research Focus & Metrics

Academic Career Length

25Years (2002-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 January 2012
Verified
Book Chapter
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DMDavid Martínez
David Martínez
ELEduardo Lleida
Eduardo Lleida
AOAlfonso Ortega
Alfonso Ortega
AMAntonio Miguel
Antonio Miguel
JVJesús Villalba
Jesús Villalba

10 February 2023 in IEEE Access
Verified
Journal Article
Open access
DRDayana Ribas
Dayana Ribas
MPMiguel A. Pastor
Miguel A. Pastor
AMAntonio Miguel
Antonio Miguel
DMDavid Martinez
David Martinez
AOAlfonso Ortega
Alfonso Ortega
ELEduardo Lleida
Eduardo Lleida
Many speech features and models, including Deep Neural Networks (DNN), are used for classification tasks between healthy and pathological speech with the Saarbruecken Voice Database (SVD). However, accuracy values of 80.71% for phrases or 82.8% for vowels /aiu/ are the highest reported for audio samples in SVD when the evaluation includes the wide amount of pathologies in the database, instead of a selection of some pathologies. This paper targets this top performance in the state-of-the-art Automatic Voice Disorder Detection (AVDD) systems. In the framework of a DNN-based AVDD system we study the capability of Self-Supervised (SS) representation learning for describing discriminative cues between healthy and pathological speech. The system processes the SS temporal sequence of features with a single feed-forward layer and Class-Token (CT) Transformer for obtaining the classification between healthy and pathological speech. Furthermore, there is evaluated a suitable data extension of the training set with out-of-domain data is also evaluated to deal with the low availability of data for using DNN-based models in voice pathology detection. Experimental results using audio samples corresponding to phrases in the SVD dataset, including all pathologies available, show classification accuracy values until 93.36%. This means that the proposed AVDD system achieved accuracy improvements of 4.1% without the training data extension, and 15.62% after the training data extension compared to the baseline system. Beyond the novelty of using SS representations for AVDD, the fact of obtaining accuracies over 90% in these conditions and using the whole set of pathologies in the SVD is a milestone for voice disorder-related research. Furthermore, the study on the amount of in-domain data in the training set related to the system performance show guidance for the data preparation stage. Lessons learned in this work suggest guidelines for taking advantage of DNN, to boost the performance in developing automatic systems for diagnosis, treatment, and monitoring of voice pathologies.

11 December 2019 in Applied Sciences
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Journal Article
Open access
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ELEduardo Lleida
Eduardo Lleida
AOAlfonso Ortega
Alfonso Ortega
AMAntonio Miguel
Antonio Miguel
VBVirginia Bazán-Gil
Virginia Bazán-Gil
MPMª Carmen Pérez
Mª Carmen Pérez
APAlberto de Prada
Alberto de Prada
The IberSpeech-RTVE Challenge presented at IberSpeech 2018 is a new Albayzin evaluation series supported by the Spanish Thematic Network on Speech Technologies (Red Temática en Tecnologías del Habla (RTTH)). That series was focused on speech-to-text transcription, speaker diarization, and multimodal diarization of television programs. For this purpose, the Corporacion Radio Television Española (RTVE), the main public service broadcaster in Spain, and the RTVE Chair at the University of Zaragoza made more than 500 h of broadcast content and subtitles available for scientists. The dataset included about 20 programs of different kinds and topics produced and broadcast by RTVE between 2015 and 2018. The programs presented different challenges from the point of view of speech technologies such as: the diversity of Spanish accents, overlapping speech, spontaneous speech, acoustic variability, background noise, or specific vocabulary. This paper describes the database and the evaluation process and summarizes the results obtained.

5 March 2020 in EURASIP Journal on Audio, Speech, and Music Processing
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Journal Article
Open access
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Pablo GimenoPablo Gimeno
Pablo Gimeno
IVIgnacio Viñals
Ignacio Viñals
AOAlfonso Ortega
Alfonso Ortega
AMAntonio Miguel
Antonio Miguel
ELEduardo Lleida
Eduardo Lleida
This paper presents a new approach based on recurrent neural networks (RNN) to the multiclass audio segmentation task whose goal is to classify an audio signal as speech, music, noise or a combination of these. The proposed system is based on the use of bidirectional long short-term Memory (BLSTM) networks to model temporal dependencies in the signal. The RNN is complemented by a resegmentation module, gaining long term stability by means of the tied state concept in hidden Markov models. We explore different neural architectures introducing temporal pooling layers to reduce the neural network output sampling rate. Our findings show that removing redundant temporal information is beneficial for the segmentation system showing a relative improvement close to 5%. Furthermore, this solution does not increase the number of parameters of the model and reduces the number of operations per second, allowing our system to achieve a real-time factor below 0.04 if running on CPU and below 0.03 if running on GPU. This new architecture combined with a data-agnostic data augmentation technique called mixup allows our system to achieve competitive results in both the Albayzín 2010 and 2012 evaluation datasets, presenting a relative improvement of 19.72% and 5.35% compared to the best results found in the literature for these databases.

28 May 2015 in ACM Transactions on Accessible Computing
Verified
Journal Article
Open access
DMDavid Martínez
David Martínez
ELEduardo Lleida
Eduardo Lleida
PGPhil Duncan Green
Phil Duncan Green
HCHeidi Christensen
Heidi Christensen
AOAlfonso Ortega
Alfonso Ortega
AMAntonio Miguel
Antonio Miguel
Automated intelligibility assessments can support speech and language therapists in determining the type of dysarthria presented by their clients. Such assessments can also help predict how well a person with dysarthria might cope with a voice interface to assistive technology. Our approach to intelligibility assessment is based on iVectors , a set of measures that capture many aspects of a person’s speech, including intelligibility. The major advantage of iVectors is that they compress all acoustic information contained in an utterance into a reduced number of measures, and they are very suitable to be used with simple predictors. We show that intelligibility assessments work best if there is a pre-existing set of words annotated for intelligibility from the speaker to be evaluated, which can be used for training our system. We discuss the implications of our findings for practice.

1 September 2020 in Computer Speech & Language
Verified
Journal Article
Closed access
VMVictoria Mingote
Victoria Mingote
AMAntonio Miguel
Antonio Miguel
AOAlfonso Ortega
Alfonso Ortega
ELEduardo Lleida
Eduardo Lleida