Contributions to impedance shaping control techniques for power electronic converters

El conformado de la impedancia o admitancia mediante control para convertidores electrónicos de potencia permite alcanzar entre otros objetivos: mejora de la robustez de los controles diseñados, amortiguación de la dinámica de la tensión en caso de cambios de carga, y optimización del filtro de red y del controlador en un solo paso (co-diseño). La conformación de la impedancia debe ir siempre acompañada de un buen seguimiento de referencias. Por tanto, la idea principal es diseñar controladores con una estructura sencilla que equilibren la consecución de los objetivos marcados en cada caso. Este diseño se realiza mediante técnicas modernas, cuya resolución (síntesis del controlador) requiere de herramientas de optimización. La principal ventaja de estas técnicas sobre las clásicas, es decir, las basadas en soluciones algebraicas, es su capacidad para tratar problemas de control complejos (plantas de alto orden y/o varios objetivos) de una forma considerablemente sistemática. El primer problema de control por conformación de la impedancia consiste en reducir el sobreimpulso de tensión ante cambios de carga y minimizar el tamaño de los componentes del filtro pasivo en los convertidores DC-DC. Posteriormente, se diseñan controladores de corriente y tensión para un inversor DC-AC trifásico que logren una estabilidad robusta del sistema para una amplia variedad de filtros. La condición de estabilidad robusta menos conservadora, siendo la impedancia de la red la principal fuente de incertidumbre, es el índice de pasividad. En el caso de los controladores de corriente, el impacto de los lazos superiores en la estabilidad basada en la impedancia también se analiza mediante un índice adicional: máximo valor singular. Cada uno de los índices se aplica a un rango de frecuencias determinado. Finalmente, estas condiciones se incluyen en el diseño en un solo paso del controlador de un convertidor back-to-back utilizado para operar generadores de inducción doblemente alimentados (aerogeneradores tipo 3) presentes en algunos parques eólicos. Esta solución evita los problemas de oscilación subsíncrona, derivados de las líneas de transmisión con condensadores de compensación en serie, a los que se enfrentan estos parques eólicos. Los resultados de simulación y experimentales demuestran la eficacia y versatilidad de la propuesta.Impedance or admittance shaping by control for power electronic converters allows to achieve among other objectives: robustness enhancement of the designed controls, damped voltage dynamics in case of load changes, and grid filter and controller optimization in a single step (co-design). Impedance shaping must always be accompanied by a correct reference tracking performance. Therefore, the main idea is to design controllers with a simple structure that balance the achievement of the objectives set in each case. This design is carried out using modern techniques, whose resolution (controller synthesis) requires optimization tools. The main advantage of these techniques over the classical ones, i.e. those based on algebraic solutions, is their ability to deal with complex control problems (high order plants and/or several objectives) in a considerably systematic way. The first impedance shaping control problem is to reduce voltage overshoot under load changes and minimize the size of passive filter components in DC-DC converters. Subsequently, current and voltage controllers for a three-phase DC-AC inverter are designed to achieve robust system stability for a wide variety of filters. The least conservative robust stability condition, with grid impedance being the main source of uncertainty, is the passivity index. In the case of current controllers, the impact of higher loops on impedance-based stability is also analyzed by an additional index: maximum singular value. Each of the indices is applied to a given frequency range. Finally, these conditions are included in the one-step design of the controller of a back-to-back converter used to operate doubly fed induction generators (type-3 wind turbines) present in some wind farms. This solution avoids the sub-synchronous oscillation problems, derived from transmission lines with series compensation capacitors, faced by these wind farms. Simulation and experimental results demonstrate the effectiveness and versatility of the proposa

Control analysis and design of medium voltage converter with multirate techniques

This work aims to unify the current knowledge about multirate controllers with design techniques for grid-tied converters, in this occasion, connected to Medium Voltage AC grid. Therefore, the multirate contributions, that have been given so far, are studied, as well as everything related to modulation techniques for power converters. The temporal implications of the DSPWM actuator will be correlated to multirate analysis, in addition to possible alternatives for applications with a lower sampling frequency than modulation one. Finalizing with explanations and result demonstrations of controllers working between two frequencies or rates, by means of the available power converter in laboratory.Este trabajo pretende unir el conocimiento actual sobre controladores multitasa o multifrecuencia (multirate) con técnicas de diseño para convertidores conectados a la red, en este caso concreto, a la red alterna (AC) de Media Tensión. Por tanto, se estudian las contribuciones multirate realizadas hasta la fecha, así como todo lo relacionado con la modulación de la señal de control para los convertidores. Las implicaciones temporales del actuador DSPWM se relacionarán con el análisis multitasa, así como se explicarán posibles alternativas para aplicaciones con una frecuencia de muestreo menor que la de modulación. Finalizando con la explicación y presentación de resultados de controladores trabajando entre dos frecuencias o tasas, mediante simulaciones del convertidor disponible en laboratorio.Máster Universitario en Ingeniería Industrial (M141

Towards a complete Binary Key System for the Speaker Diarization Task

International audienceSpeaker diarization is the task of partitioning an audio stream into homogeneous segments according to speaker identity. Today state-of-the-art speaker diarization systems have achieved very competitive performance. However, any small improvement in Diarization Error Rate (DER) is usually subject to very large processing times (real time factor above one), which makes systems not suitable for some time-critical, real-life applications. Recently, a novel fast speaker diarization technique based on speaker modeling using binary keys was presented. The proposed technique speeds up the process up to ten times faster than real-time with little increase of DER. Although the approach shows great potential, the presented results are still preliminary. The goal of this paper is to further investigate this technique, in order to move towards a complete binary-key based system for the speaker diarization task. Preliminary experiments in Speech Activity Detection (SAD) based on binary keys show the feasibility of the binary key modeling approach for this task. Furthermore, the system has been tested on two different kinds of test data: meeting audio recordings and TV shows. The experiments carried out on NIST RT05 and REPERE databases show promising results and indicate that there is still room for further improvement

Speaker diarization and speech recognition in the semi-automatization of audio description : an exploratory study on future possibilities?

This article presents an overview of the technological components used in the process of audio description, and suggests a new scenario in which speech recognition, machine translation, and text-to-speech, with the corresponding human revision, could be used to increase audio description provision. The article focuses on a process in which both speaker diarization and speech recognition are used in order to obtain a semi-automatic transcription of the audio description track. The technical process is presented and experimental results are summarizedEste artículo presenta una visión panorámica de los componentes tecnológicos usados en el proceso de audiodescripción y propone un nuevo escenario en el que se aplicarían el reconocimiento de habla, la traducción automática y la síntesis de habla, con su correspondiente revisión humana, para incrementar la cantidad de audiodescripciones disponibles. El artículo describe un proceso en el que la diarización y el reconocimiento de habla permiten obtener una transcripción semiautomática de la audiodescripción. El artículo presenta detalladamente el proceso técnico así como un resumen de los resultados experimentales.- In a second languag

Vasculogenic mimicry signaling revisited: focus on non-vascular VE-cadherin

Vasculogenic mimicry (VM) is a blood supply system independent of endothelial vessels in tumor cells from different origins. It reflects the plasticity of aggressive tumor cells that express vascular cell markers and line tumor vasculature. The presence of VM is associated with a high tumor grade, short survival, invasion and metastasis. Endothelial cells (ECs) express various members of the cadherin superfamily, in particular vascular endothelial (VE-) cadherin, which is the main adhesion receptor of endothelial adherent junctions. Aberrant extra-vascular expression of VE-cadherin has been observed in certain cancer types associated with VM. In this review we focus on non-endothelial VE-cadherin as a prominent factor involved in the acquisition of tubules-like structures by aggressive tumor cells and we summarize the specific signaling pathways, the association with trans-differentiation and stem-like phenotype and the therapeutic opportunities derived from the in-depth knowledge of the peculiarities of the biology of VE-cadherin and other key components of VM.Junta de Andalucía P07-CTS-0239Junta de Andalucía P10-CTS-0662Junta de Andalucía P10-CTS-383España, MINECO SAF2009-13281-C02-01España, MINECO SAF2015-70520-REspaña, MINECO RTICC RD12/0036/0026España, CIBERONC ISCIII CB16/12/0042

Distributor performance in a bubbling fluidized bed: Effects of multiple gas inlet jet and bubble generation

This study considers the role of the distributor effect during the bubble generation, growth and interaction within a bubbling fluidized bed. To characterize this effect, short-term and long-term dynamics are explored in time and frequency domains. Controversy occurs when inspecting what is actually known of the gas distribution mechanism in bubbling fluidized beds. To sustain discussion, classical and innovative techniques, such as Digital Image Analysis, DIA, and Wavelet Analysis WA, are used. As a result, the conclusion is that the distributor not only has no effect in the averaged long-term dynamics but also has no effect on the general bubble generation characteristic frequencies. The analysis performed on the bubble generation region concludes that the distributor design has a great influence at the short-term scale such as during the bubble generation process controlling the spatial distribution of the bubble nucleation sites over the distributor plate

Prevention of Emotional Disorders and Symptoms Under Health Conditions: A Pilot Study using the Unified Protocol in a Fertility Unit

Emotional Disorders (EDs) are common in women who undergo fertility treatments. The Unified Protocol (UP) is a transdiagnostic intervention that has demonstrated efficacy in preventing EDs under different health conditions. The aim of this pilot study is to: 1) improve emotional dysregulation for the prevention of anxiety and depressive symptoms in women undergoing intrauterine inseminations (IUI); 2) assess their acceptability (e.g., satisfaction and adherence rates). Method: Five women undergoing IUI, with no clinical diagnoses, responded to measures of mood (anxiety and depression), affect, quality of life and emotional dysregulation in the pre- and post-assessments, and at the 1-, 3- and 6-month follow-ups. The UP was adapted to be applied during six face-to-face group sessions lasting 2 h. The COVID-19 pandemic situation implied changing to an online format to end the program. Results: The results showed that women did not develop EDs, and no statistically significant pre-post and pre-follow-up differences were found for anxiety, depression, quality of life and emotional dysregulation (all p > .050). A tendency towards improvement in the post-assessment evaluation was noted. Satisfaction with the format and UP program was high. Conclusions: It would seem that programs focusing on therapeutic common factors like the UP could have an emotional preventive effect during IUI

MYC as therapeutic target in leukemia and lymphoma

MYC is a transcription factor that is involved in the expression of many genes. Deregulated MYC is found in about half of human tumors, being more prevalent in hematological neoplasms. Deregulation mechanisms include chromosomal translocation (particularly in lymphoma), amplification, and hyperactivation of MYC transcription. Here we review MYC involvement in the major types of leukemia and lymphoma. MYC rearrangements appear in all Burkitt lymphomas and are common in other lymphoma types, whereas in acute lymphoblastic leukemia, acute myeloid leukemia, lymphoproliferative, and myeloproferative diseases, they are less frequent. However, MYC overexpression is present in all types of hematological malignancies and often correlates with a worse prognosis. Data in leukemia-derived cells and in animal models of lymphomagenesis and leukemogenesis suggest that MYC would be a good therapeutic target. Several MYC-directed therapies have been assayed in preclinical settings and even in clinical trials. First, peptides and small molecules that interrupt the MYC–MAX interaction impair MYC-mediated tumorogenesis in several mouse models of solid tumors, although not yet in lymphoma and leukemia models. Second, there are a number of small molecules inhibiting the interaction of MYC–MAX heterodimers with DNA, still in the preclinical research phase. Third, inhibitors of MYC expression via the inhibition of BRD4 (a reader of acetylated histones) have been shown to control the growth of MYC-transformed leukemia and lymphoma cells and are being used in clinic trials. Finally, we review a number of promising MYC-mediated synthetic lethal approaches that are under study and have been tested in hematopoietic neoplasms

Circulating miRNAs as predictive biomarkers of type 2 diabetes mellitus development in coronary heart disease patients fromt he CORDIOPREV study

Circulating microRNAs (miRNAs) have been proposed as type 2 diabetes biomarkers, and they may be a more sensitive way to predict development of the disease than the currently used tools. Our aim was to identify whether circulating miRNAs, added to clinical and biochemical markers, yielded better potential for predicting type 2 diabetes. The study included 462 non-diabetic patients at baseline in the CORDIOPREV study. After a median follow-up of 60 months, 107 of them developed type 2 diabetes. Plasma levels of 24 miRNAs were measured at baseline by qRT-PCR, and other strong biomarkers to predict diabetes were determined. The ROC analysis identified 9 miRNAs, which, added to HbA1c, have a greater predictive value in early diagnosis of type 2 diabetes (AUC = 0.8342) than HbA1c alone (AUC = 0.6950). The miRNA and HbA1cbased model did not improve when the FINDRISC was included (AUC = 0.8293). Cox regression analyses showed that patients with low miR-103, miR-28-3p, miR-29a, and miR-9 and high miR-30a-5p and miR-150 circulating levels have a higher risk of disease (HR = 11.27; 95% CI = 2.61–48.65). Our results suggest that circulating miRNAs could potentially be used as a new tool for predicting the development of type 2 diabetes in clinical practice

Albayzín-2014 evaluation: audio segmentation and classification in broadcast news domains

The electronic version of this article is the complete one and can be found online at: http://dx.doi.org/10.1186/s13636-015-0076-3Audio segmentation is important as a pre-processing task to improve the performance of many speech technology tasks and, therefore, it has an undoubted research interest. This paper describes the database, the metric, the systems and the results for the Albayzín-2014 audio segmentation campaign. In contrast to previous evaluations where the task was the segmentation of non-overlapping classes, Albayzín-2014 evaluation proposes the delimitation of the presence of speech, music and/or noise that can be found simultaneously. The database used in the evaluation was created by fusing different media and noises in order to increase the difficulty of the task. Seven segmentation systems from four different research groups were evaluated and combined. Their experimental results were analyzed and compared with the aim of providing a benchmark and showing up the promising directions in this field.This work has been partially funded by the Spanish Government and the European Union (FEDER) under the project TIN2011-28169-C05-02 and supported by the European Regional Development Fund and the Spanish Government (‘SpeechTech4All Project’ TEC2012-38939-C03