Utilising Tree-Based Ensemble Learning for Speaker Segmentation

Part 2: Learning-Ensemble LearningInternational audienceIn audio and speech processing, accurate detection of the changing points between multiple speakers in speech segments is an important stage for several applications such as speaker identification and tracking. Bayesian Information Criteria (BIC)-based approaches are the most traditionally used ones as they proved to be very effective for such task. The main criticism levelled against BIC-based approaches is the use of a penalty parameter in the BIC function. The use of this parameters consequently means that a fine tuning is required for each variation of the acoustic conditions. When tuned for a certain condition, the model becomes biased to the data used for training limiting the model’s generalisation ability.In this paper, we propose a BIC-based tuning-free approach for speaker segmentation through the use of ensemble-based learning. A forest of segmentation trees is constructed in which each tree is trained using a sampled version of the speech segment. During the tree construction process, a set of randomly selected points in the input sequence is examined as potential segmentation points. The point that yields the highest ΔBIC is chosen and the same process is repeated for the resultant left and right segments. The tree is constructed where each node corresponds to the highest ΔBIC with the associated point index. After building the forest and using all trees, the accumulated ΔBIC for each point is calculated and the positions of the local maximums are considered as speaker changing points. The proposed approach is tested on artificially created conversations from the TIMIT database. The approach proposed show very accurate results comparable to those achieved by the-state-of-the-art methods with a 9% (absolute) higher F1 compared with the standard ΔBIC with optimally tuned penalty parameter

Complementariedad entre las relaciones diacrónicas de los T-Patterns y los patrones de conducta en acciones de esgrima de espada masculina de élite

El objetivo de este artículo es establecer las posibles relacionesdiacrónicas detectadas en el análisis táctico de los asaltos de esgrima deespada masculina, desde tres técnicas analíticas complementarias. Se utilizóun diseño observacional nomotético, puntual y multidimensional enel registro de ocho asaltos de dos esgrimistas finalistas en los mundialesde Budapest 2013 y Kazán 2014. Se utilizó el instrumento de observaciónESGRIMOBS. En el muestreo observacional realizado con LINCE v.1.1 seregistraron 407 frases de armas. El análisis metodológico se realizó con losprogramas THEME v.6 Edu, GSEQ5 y HOISAN. Los resultados concluyenel interés de este análisis complementario a través de dos claras orientaciones.En primer lugar, un análisis táctico (intra-frase de armas), que vinculael pensamiento táctico con la ejecución técnica específica y su eficacia.Este análisis intra-frase de armas se lleva a cabo mediante el análisis secuencialdel Retardo 0 (análisis de coocurrencias) y las configuraciones de losT-Patterns. En segundo lugar, un análisis estratégico (inter-frases de armas)que nos informa de la relación bidireccional, prospectiva y retrospectiva, delas acciones de esgrima en relación a su eficacia. Este análisis inter-frases dearmas se realiza mediante el análisis secuencial en los retardos -1 a -5 y +1a +5, las agrupaciones de clusters de los T-Patterns y el análisis de coordenadaspolares. Estas herramientas nos permiten establecer relaciones directasentre las distintas acciones tácticas y su eficacia en el marcador, así comosobre las operaciones estratégicas de los tiradores durante la competición,pudiendo constituir un excelente complemento para la mejora de la tomade decisiones de los esgrimistas

Influencia del pick and roll en el juego de ataque en baloncesto de alto nivel

El objetivo de este estudio fue caracterizar las acciones del pickand roll y su influencia en el juego en baloncesto de alto nivel. Se analizóla eficacia táctica y de marcador en función de distintos factores queinciden en las situaciones de juego mediante un diseño observacional nomotético,puntual y multidimensional en 18 equipos de la liga ACB debaloncesto. Un instrumento observacional ad hoc (VTP&R) fue validadopor un panel de 20 expertos de alto nivel y se comprobó la fiabilidad en laobservación por parte de los investigadores. El análisis de datos se realizómediante el análisis secuencial de retardos, el análisis de coordenadaspolares y los estadísticos descriptivos cuantitativos. Del total de accionesanalizadas (n=3895), el 25,3% se corresponden a pick and roll (n=984). Soloel 36,3% de las acciones de pick and roll se han mostrado eficaces en elmarcador, mientras que el 85,7% lo son tácticamente. La interpretaciónde los resultados muestra el interés en complementar el análisis del juegoen baloncesto a través de los mixed methods. La posibilidad de determinarqué acciones se realizan en cada momento del partido y de qué manera seejecutan, así como establecer patrones de respuesta táctica en función delos distintos factores que intervienen en el juego, justifica la utilidad de losresultados aquí obtenidos y se concluye el interés en incorporar las distintastécnicas analíticas de la metodología observacional a los procesos de análisisdel baloncesto

Tsx Produces a Long Noncoding RNA and Has General Functions in the Germline, Stem Cells, and Brain

The Tsx gene resides at the X-inactivation center and is thought to encode a protein expressed in testis, but its function has remained mysterious. Given its proximity to noncoding genes that regulate X-inactivation, here we characterize Tsx and determine its function in mice. We find that Tsx is actually noncoding and the long transcript is expressed robustly in meiotic germ cells, embryonic stem cells, and brain. Targeted deletion of Tsx generates viable offspring and X-inactivation is only mildly affected in embryonic stem cells. However, mutant embryonic stem cells are severely growth-retarded, differentiate poorly, and show elevated cell death. Furthermore, male mice have smaller testes resulting from pachytene-specific apoptosis and a maternal-specific effect results in slightly smaller litters. Intriguingly, male mice lacking Tsx are less fearful and have measurably enhanced hippocampal short-term memory. Combined, our study indicates that Tsx performs general functions in multiple cell types and links the noncoding locus to stem and germ cell development, learning, and behavior in mammals

FlexOracle: predicting flexible hinges by identification of stable domains

<p>Abstract</p> <p>Background</p> <p>Protein motions play an essential role in catalysis and protein-ligand interactions, but are difficult to observe directly. A substantial fraction of protein motions involve hinge bending. For these proteins, the accurate identification of flexible hinges connecting rigid domains would provide significant insight into motion. Programs such as GNM and FIRST have made global flexibility predictions available at low computational cost, but are not designed specifically for finding hinge points.</p> <p>Results</p> <p>Here we present the novel FlexOracle hinge prediction approach based on the ideas that energetic interactions are stronger <it>within </it>structural domains than <it>between </it>them, and that fragments generated by cleaving the protein at the hinge site are independently stable. We implement this as a tool within the Database of Macromolecular Motions, MolMovDB.org. For a given structure, we generate pairs of fragments based on scanning all possible cleavage points on the protein chain, compute the energy of the fragments compared with the undivided protein, and predict hinges where this quantity is minimal. We present three specific implementations of this approach. In the first, we consider only pairs of fragments generated by cutting at a <it>single </it>location on the protein chain and then use a standard molecular mechanics force field to calculate the enthalpies of the two fragments. In the second, we generate fragments in the same way but instead compute their free energies using a knowledge based force field. In the third, we generate fragment pairs by cutting at <it>two </it>points on the protein chain and then calculate their free energies.</p> <p>Conclusion</p> <p>Quantitative results demonstrate our method's ability to predict known hinges from the Database of Macromolecular Motions.</p

Regulatory RNAs and chromatin modification in dosage compensation: A continuous path from flies to humans?

Chromosomal sex determination is a widely distributed strategy in nature. In the most classic scenario, one sex is characterized by a homologue pair of sex chromosomes, while the other includes two morphologically and functionally distinct gonosomes. In mammalian diploid cells, the female is characterized by the presence of two identical X chromosomes, while the male features an XY pair, with the Y bearing the major genetic determinant of sex, i.e. the SRY gene. In other species, such as the fruitfly, sex is determined by the ratio of autosomes to X chromosomes. Regardless of the exact mechanism, however, all these animals would exhibit a sex-specific gene expression inequality, due to the different number of X chromosomes, a phenomenon inhibited by a series of genetic and epigenetic regulatory events described as "dosage compensation". Since adequate available data is currently restricted to worms, flies and mammals, while for other groups of animals, such as reptiles, fish and birds it is very limited, it is not yet clear whether this is an evolutionary conserved mechanism. However certain striking similarities have already been observed among evolutionary distant species, such as Drosophila melanogaster and Mus musculus. These mainly refer to a) the need for a counting mechanism, to determine the chromosomal content of the cell, i.e. the ratio of autosomes to gonosomes (a process well understood in flies, but still hypothesized in mammals), b) the implication of non-translated, sex-specific, regulatory RNAs (roX and Xist, respectively) as key elements in this process and the location of similar mediators in the Z chromosome of chicken c) the inclusion of a chromatin modification epigenetic final step, which ensures that gene expression remains stably regulated throughout the affected area of the gonosome. This review summarizes these points and proposes a possible role for comparative genetics, as they seem to constitute proof of maintained cell economy (by using the same basic regulatory elements in various different scenarios) throughout numerous centuries of evolutionary history

Spoken term detection ALBAYZIN 2014 evaluation: overview, systems, results, and discussion

The electronic version of this article is the complete one and can be found online at: http://dx.doi.org/10.1186/s13636-015-0063-8Spoken term detection (STD) aims at retrieving data from a speech repository given a textual representation of the search term. Nowadays, it is receiving much interest due to the large volume of multimedia information. STD differs from automatic speech recognition (ASR) in that ASR is interested in all the terms/words that appear in the speech data, whereas STD focuses on a selected list of search terms that must be detected within the speech data. This paper presents the systems submitted to the STD ALBAYZIN 2014 evaluation, held as a part of the ALBAYZIN 2014 evaluation campaign within the context of the IberSPEECH 2014 conference. This is the first STD evaluation that deals with Spanish language. The evaluation consists of retrieving the speech files that contain the search terms, indicating their start and end times within the appropriate speech file, along with a score value that reflects the confidence given to the detection of the search term. The evaluation is conducted on a Spanish spontaneous speech database, which comprises a set of talks from workshops and amounts to about 7 h of speech. We present the database, the evaluation metrics, the systems submitted to the evaluation, the results, and a detailed discussion. Four different research groups took part in the evaluation. Evaluation results show reasonable performance for moderate out-of-vocabulary term rate. This paper compares the systems submitted to the evaluation and makes a deep analysis based on some search term properties (term length, in-vocabulary/out-of-vocabulary terms, single-word/multi-word terms, and in-language/foreign terms).This work has been partly supported by project CMC-V2 (TEC2012-37585-C02-01) from the Spanish Ministry of Economy and Competitiveness. This research was also funded by the European Regional Development Fund, the Galician Regional Government (GRC2014/024, “Consolidation of Research Units: AtlantTIC Project” CN2012/160)

The role of the cerebellum in adaptation: ALE meta‐analyses on sensory feedback error

It is widely accepted that unexpected sensory consequences of self‐action engage the cerebellum. However, we currently lack consensus on where in the cerebellum, we find fine‐grained differentiation to unexpected sensory feedback. This may result from methodological diversity in task‐based human neuroimaging studies that experimentally alter the quality of self‐generated sensory feedback. We gathered existing studies that manipulated sensory feedback using a variety of methodological approaches and performed activation likelihood estimation (ALE) meta‐analyses. Only half of these studies reported cerebellar activation with considerable variation in spatial location. Consequently, ALE analyses did not reveal significantly increased likelihood of activation in the cerebellum despite the broad scientific consensus of the cerebellum's involvement. In light of the high degree of methodological variability in published studies, we tested for statistical dependence between methodological factors that varied across the published studies. Experiments that elicited an adaptive response to continuously altered sensory feedback more frequently reported activation in the cerebellum than those experiments that did not induce adaptation. These findings may explain the surprisingly low rate of significant cerebellar activation across brain imaging studies investigating unexpected sensory feedback. Furthermore, limitations of functional magnetic resonance imaging to probe the cerebellum could play a role as climbing fiber activity associated with feedback error processing may not be captured by it. We provide methodological recommendations that may guide future studies