Estrategias de calentamiento en bandidos multi-brazo para recomendación

Trabajo Fin de Máster en Investigación e Innovación en Inteligencia Computacional y Sistemas InteractivosRecommender systems have become an essential piece of multiple online platforms such as streaming services and e-commerce in the last years as they provide users with articles they may find interesting and thus granting them a personalised experience. The recommendation problem has many opened investigation lines. One of them is the topic we tackle in this work: the cold-start problem. In the context of recommender systems the cold-start problem refers to the situation in which a system does not have enough information to give proper suggestions to the user. The cold-start problem often occurs because of the following three main reasons: the user to be recommended is new to the system and thus there is no information about its likes, some of the items that are recommended have been recently added to the system and they do not have users’ reviews, or the system is completely new and there is no information about the users nor the items. Classical recommendation techniques come from Machine learning and they understand recommendation as an static process in which the system provides suggestions to the user and the last rates them. It is more convenient to understand recommendation as a cycle of constant interaction between the user and the system and every time a user rates an item, the system uses it to learn from the user. In that sense we can sacrifice immediate reward in order to earn information about the user and improve long term reward. This schema establishes a balance between exploration (non-optimal recommendations to learn about the user) and exploitation (optimal recommendations to maximise the reward). Techniques known as multi-armed bandits are used to get that balance between exploration and exploitation and we propose them to tackle cold-start problem. Our hypothesis is that an exploration in the first epochs of the recommendation cycle can lead to an improvement in the reward during the latest epochs. To test this hypothesis we divide the recommendation loop in two phases: the warm-up, in which we follow a more exploratory approach to get as much information as possible; and exploitation, in which the system uses the knowledge acquired during the warm-up to maximise the reward. For this two phases we combine different recommendation strategies, among which we consider both multi-armed bandits and classic algorithms. We evaluate them offline in three datasets: CM100K (music), MovieLens1M (films) and Twitter. We also study how the warm-up duration affects the exploitation phase. Results show that in two dataset (MovieLens and Twitter) classical algorithms perform better during the exploitation phase in terms of recall after a mainly exploratory warm-up phase

Bandidos multi-brazo en sistemas de recomendación

En los últimos años los sistemas de recomendación se han convertido en una herramienta fundamental ampliamente utilizada por gran cantidad de servicios muy diversos, tales como comercios electrónicos, redes sociales o plataformas de streaming. Este crecimiento se debe, en parte, a que los sistemas de recomendación proporcionan grandes ventajas tanto para el usuario, en tanto que mejoran su experiencia proporcionándole ideas sobre qué contenido consumir, como para los proveedores del servicio, ya que favorecen el consumo por parte de los usuarios y les ayudan a descubrir productos que de otra forma no habrían conocido. Este creciente auge de los sistemas de recomendación ha promovido el desarrollo de técnicas y herramientas software que persiguen la satisfacción por parte del usuario centrándose en mejorar las recomendaciones. Estas técnicas tienen un gran fundamento en el campo del Aprendizaje supervisado, puesto que la tarea de recomendación se ha entendido de manera tradicional como un problema de predicción. El hecho de tratar las recomendaciones como una predicción de la puntuación que el usuario daría a cada uno de los ítems que desconoce, supone entender la recomendación desde un punto de vista estático de un único paso en el que se busca el acierto inmediato sin tener en cuenta las consecuencias a largo plazo. Este trabajo aborda una nueva perspectiva en cuanto la recomendación que supone romper con este enfoque más tradicional: el Aprendizaje por Refuerzo. Mediante este nuevo enfoque, la recomendación pasa a entenderse como un proceso de aprendizaje continuo en el que las interacciones del usuario con las recomendaciones se aprovechan para adquirir nuevo conocimiento y mejorar a futuro. Por ello, se admite un sacrificio del acierto inmediato en pro de obtener un mayor beneficio a largo plazo. Esta idea de proceso interactivo entre usuario y sistema resulta mucho más natural que el enfoque estático más tradicional inspirado por el Aprendizaje supervisado. Más concretamente en este trabajo se profundiza en técnicas conocidas como bandidos multi-brazo, que tienen base en la teoría de la probabilidad, aplicadas a la tarea de la recomendación no personalizada. Dentro de los bandidos multi-brazo, se estudian los algoritmos de "-Greedy, Upper Confidence Bound y Thompson Sampling, comparándolos entre sí y con algoritmos clásicos de recomendación no personalizada en diferentes conjuntos de datos. Los resultados obtenidos indican que en todos los conjuntos de datos existen configuraciones de al menos uno de los algoritmos anteriores que mejoran el acierto con respecto a los algoritmos de recomendación sin refuerzo

El trabajo emocional desde una perspectiva clarificadora, tras treinta años de investigación

El presente trabajo tiene como objetivo el análisis del concepto de ¿trabajo emocional¿. Específicamente, a través de un enfoque integrador, se pretende clarificar a qué hace referencia el trabajo emocional y diferenciarlo de conceptos con los que comúnmente se relaciona en la literatura existente. Además, se analiza una de las últimas propuestas sobre cómo se podría producir el trabajo emocional aplicado al contexto de las organizaciones de servicios. Por último, se analizan los antecedentes que la literatura señala como aspectos potenciales para la aparición del trabajo emocional y las consecuencias que éste puede ocasionar en los resultados organizacionales, como es la calidad de servicio y en la salud psicosocial de los trabajadores

Latent heat thermophotovoltaic batteries

Latent heat thermophotovoltaic (LHTPV) batteries store electricity as latent heat at very high temperatures (>1,000°C) and convert this heat back to electricity on demand using thermophotovoltaics (TPVs). In this study, we discuss the techno-economics of LHTPV systems, focusing on parameters such as the round-trip efficiency, energy-to-power ratio, cost per energy and power capacities, and levelized cost of storage. The very low cost of the heat storage media (<4 €/kWh) results in optimal designs with high energy-to-power ratios, fitting long-duration storage (LDS) applications. Shorter-duration storage applications are also possible by increasing the overall round-trip conversion efficiency through cogeneration, that is, combined heat and power (CHP) generation. Results indicate that LHTPV systems can provide lower levelized cost of storage than Li-ion batteries in both LDS and CHP applications. Preliminary experimental results are provided to illustrate the real operation of a LHTPV systemObjectius de Desenvolupament Sostenible::14 - Vida SubmarinaPostprint (author's final draft

Effectiveness of pelvic floor muscle training in treating urinary incontinence in women: A current review.

OBJECTIVE: To analyse the content of various published studies related to physical exercise and its effects on urinary incontinence and to determine the effectiveness of pelvic floor training programmes. METHOD: We conducted a search in the databases of PubMed, CINAHL, the Cochrane Plus Library, The Cochrane Library, WOS and SPORTDiscus and a manual search in the Google Scholar metasearcher using the search descriptors for documents published in the last 10 years in Spanish or English. The documents needed to have an abstract or complete text on the treatment of urinary incontinence in female athletes and in women in general. RESULTS: We selected 3 full-text articles on treating urinary incontinence in female athletes and 6 full-text articles and 1 abstract on treating urinary incontinence in women in general. The 9 studies included in the review achieved positive results, i.e., there was improvement in the disease in all of the studies. CONCLUSIONS: Physical exercise, specifically pelvic floor muscle training programmes, has positive effects on urinary incontinence. This type of training has been shown to be an effective programme for treating urinary incontinence, especially stress urinary incontinence.Actividad Física y Deport

Measurement of anti-DFS70 antibodies in patients with ANA-associated autoimmune rheumatic diseases suspicion is cost-effective

The presence of antinuclear antibodies (ANA) is associated with a wide range of ANA-associated autoimmune rheumatic diseases (AARD). The most commonly method used for the detection of ANA is indirect immunofluorescence (IIF) on HEp-2 cells. This method is very sensitive but unspecific. As a consequence, ANA testing on HEp-2 substrates outside a proper clinical specialist framework may lead to inappropriate referrals to tertiary care specialists and, worst case inappropriate and potentially toxic therapy for the patient. Among ANA, isolated anti-DFS70 antibodies represent a potentially important biomarker that can be clinically used to discriminate AARD from non-AARD patients in ANA IIF positive individuals. Therefore, their presence may avoid unnecessary follow-up testing and referrals. In our study, we investigated if the implementation of a new ANA workup algorithm allowing for the identification of anti- DFS70 antibodies is cost-effective through the reduction of both unnecessary follow-up testing and outpatient clinic visits generated by the clinical suspicion of a potential AARD. None of the 181 patients included with a positive monospecific anti-DFS70 antibody result developed SARD during the follow-up period of 10 years. The reduction in number of tests after ANA and anti-DFS70 positive results was significant for anti-ENA (230 vs. 114 tests; p\0.001) and anti-dsDNA antibodies (448 vs. 114 tests; p\0.001). In addition, the outpatient clinic visits decreased by 70 % (p\0.001). In total, the adoption of the new algorithm including anti-DFS70 antibody testing resulted in a cost saving of 60869.53 € for this pilot study. In conclusion, the use of anti-DFS70 antibodies was clearly cost-efficient in our setting

Factores que influyen en la realización de una episiotomía selectiva en mujeres nulíparas.

Objective: To determinate factors affecting the performance of a selective episiotomy in nulliparous women.Methods: A descriptive cross-sectional study was conducted at the Miguel Servet University Hospital (HUMS) of Zaragoza within a sample of 568 nulliparous women. The  performance of episiotomy was compared to postpartum variables such as: maternal age, nationality, gestational age, fetal weight, time of birth, fetal sex, analgesia used and professional attending the birth, as well as the existence of tears and pH results fetal umbilical cord artery.Results: The rate of episiotomy in nulliparous women at HUMS of Zaragoza is 62%. Factors influencing the performance of an episiotomy are greater fetal weight (p=0,000), as well as individual professional judgment attending childbirth.Other factors such as gestational age, fetal sex, epidural analgesia, time of birth or nationality do not affect the above mentioned performance.Lack of episiotomy increases first degree perineal tears and, to a lesser extent, the second degree, without causing an increased risk for fetal wellbeing. In addition, it allows the possibility of maintaining the full perineum after birth, mainly among younger women.Conclusions: It would be advisable to revise the protocols of selective policy for episiotomy rate decrease and equalize rates between different professionals.Objetivo: Determinar los factores que influyen en la realización de una episiotomía selectiva en mujeres nulíparas. Material y método: Se realizó un estudio descriptivo transversal en el Hospital Universitario Miguel Servet (HUMS) de Zaragoza con una muestra de 568 mujeres nulíparas. Se comparó la existencia o no de episiotomía tras el parto con las variables: edad materna, nacionalidad, edad gestacional, peso fetal, hora de nacimiento, sexo fetal, analgesia empleada y profesional que asiste el parto, así como la existencia de desgarros y los resultados del pH de la arteria umbilical fetal.Resultados: La tasa de episiotomía en las mujeres nulíparas en el HUMS de Zaragoza es de un 62%. Entre los factores que influyen en la realización de una episiotomía se encuentran el mayor peso del feto (p =0,000), así como el criterio individual del profesional que asiste el parto. Otros factores como la edad gestacional, el sexo fetal, la analgesia epidural, la hora de nacimiento o la nacionalidad no influyen en su realización.El no hacer episiotomía incrementa los desgarros perineales de primer grado, y en menor medida los de segundo, sin que ocasione un mayor riesgo para el bienestar fetal. Además, su no realización permite la posibilidad de mantener el periné íntegro tras el parto, principalmente entre las mujeres más jóvenes. Conclusión: Sería recomendable revisar los protocolos de política selectiva de episiotomía para conseguir disminuir su tasa e igualar los porcentajes existentes entre los diferentes profesionales.

Diagnostic Accuracy Study Comparing Hysterosalpingo-Foam Sonography and Hysterosalpingography for Fallopian Tube Patency Assessment

Introduction: Simplified ultrasound-based infertility protocols that appear to provide enough information to plan effective management have been described. Thus, the objective of this study is to compare the diagnostic accuracy of the hysterosalpingo-foam sonography (HyFoSy) in tubal patency testing with the traditional hysterosalpngography (HSG) for establishing a new diagnostic strategy in infertility. Material and Methods: Prospective observational diagnostic accuracy was performed in a private fertility clinic in which 106 women undergoing a preconceptionally visit were recruited. All of them had low risk for tubal disease, had performed an HSG and were negative for Chlamydia trachomatis antibody. Main outcome measures were tubal patency and pain grade. Results: Evaluation of tubal patency by HyFoSy showed a total concordance with the results of the previous HSG in 72.6% (n = 77), and a total discordance for 4.7% (n = 6), with the inter-test agreement Kappa equal to 0.57, which means moderate concordance. Among the patients, 59.1% did not report pain during the procedure, while the remaining 48.1% indicated pain in different degrees; patients usually report less pain and only 6.6% described more pain with HyFoSy than with HSG (OR 6.57 (CI 95% 3.11–13.89)). Clinical outcomes after performing HyFoSy were not affected. Conclusions: HyFoSy is in concordance with HSG regarding tubal patency results and it is a less painful technique than HSG. HyFoSy is more economical and can be performed in an exam room only equipped with an ultrasound scanner. Based on these results, HyFoSy could be the first-choice diagnostic option to assess tubal patency in patients with low risk of tubal disea

Fear Detection in Multimodal affective computing: Physiological Signals versus Catecholamine Concentration

Affective computing through physiological signals monitoring is currently a hot topic in the scientific literature, but also in the industry. Many wearable devices are being developed for health or wellness tracking during daily life or sports activity. Likewise, other applications are being proposed for the early detection of risk situations involving sexual or violent aggressions, with the identification of panic or fear emotions. The use of other sources of information, such as video or audio signals will make multimodal affective computing a more powerful tool for emotion classification, improving the detection capability. There are other biological elements that have not been explored yet and that could provide additional information to better disentangle negative emotions, such as fear or panic. Catecholamines are hormones produced by the adrenal glands, two small glands located above the kidneys. These hormones are released in the body in response to physical or emotional stress. The main catecholamines, namely adrenaline, noradrenaline and dopamine have been analysed, as well as four physiological variables: skin temperature, electrodermal activity, blood volume pulse (to calculate heart rate activity. i.e., beats per minute) and respiration rate. This work presents a comparison of the results provided by the analysis of physiological signals in reference to catecholamine, from an experimental task with 21 female volunteers receiving audiovisual stimuli through an immersive environment in virtual reality. Artificial intelligence algorithms for fear classification with physiological variables and plasma catecholamine concentration levels have been proposed and tested. The best results have been obtained with the features extracted from the physiological variables. Adding catecholamine’s maximum variation during the five minutes after the video clip visualization, as well as adding the five measurements (1-min interval) of these levels, are not providing better performance in the classifiers.This research has been supported by the Madrid Governement (Comunidad de Madrid, Spain) under the ARTEMISA-UC3M-CM research project (reference 2020/00048/001), the EMPATIACM research project (reference Y2018/TCS-5046) and the Multiannual Agreement with UC3M in the line of Excellence of University Professors (EPUC3M26), and in the context of the V PRICIT (Regional Programme of Research and Technological Innovation)