An approach to build in situ models for the prediction of the decrease of academic engagement indicators in Massive Open Online Courses

Producción CientíficaThe early detection of learners who are expected to disengage with typical MOOC tasks such as watching lecture videos or submitting assignments is necessary to enable timely interventions aimed at preventing it. This can be done by predicting the decrease of academic engagement indicators that can be derived for di_erent MOOC tasks and computed for each learner. A posteriori prediction models can yield a good performance but cannot be built using the information that is available in an ongoing course at the moment the predictions are required. This paper proposes an approach to build in situ prediction models using such information. Models were derived following both approaches and employed to predict the decrease of three indicators that quantify the engagement of learners with the main tasks typically proposed in a MOOC: watching lectures, solving _nger exercises, and submitting assignments. The results show that in situ models yielded a good performance for the prediction of all engagement indicators, thus showing the feasibility of the proposed approach. This performance was very similar to that of a posteriori models, which have the clear disadvantage that they cannot be used to make predictions in an ongoing course based on its data.Ministerio de Economía, Industria y Competitividad (Projects TIN2014-53199-C3-2-R (AEI, FEDER), TIN2017-85179-C3-2-R)Junta de Castilla y León (programa de apoyo a proyectos de investigación - Ref. VA277U14)European Commission (Proyect 588438-EPP-1-2017-1-EL-EPPKA2-KA

Procedimiento para la medición y verificación de la directividad y la cobertura de una fuente sobre un elemento de fachada de acuerdo a la norma ISO 140-5

El apartado de la Norma Internacional UNE-EN ISO 140-5 [1] especifica que la directividad del altavoz usado en el ensayo debe asegurar en todas las bandas de frecuencias de interés, unas diferencias de nivel locales inferiores a 5dB (o a 10 dB para fachadas de dimensiones mayores a 5m), medidas en campo libre, sobre una superficie del mismo tamaño y orientación que la pared o elemento a ensayar. Este requisito debe verificarse en unas bandas de frecuencia de interés que sean como mínimo los tercios de octava desde 100Hz hasta 3150Hz, y preferiblemente desde 50Hz hasta 5kHz. Desde hace unos años, en el Laboratorio de sonido de la EUIT de Telecomunicación de la Universidad Politécnica de Madrid, los autores han implementado un método en el que, a partir de las medidas de directividad en cámara anecoica de la fuente sonora a ensayar, se calcula el campo sonoro directo sobre una superficie ficticia que representa un elemento de fachada en la misma disposición que se indica en la norma ICO 140-5 y con unas dimensiones según se requieran en el procedimiento. También se estima la dimensión horizontal máxima ΔXmax de una fachada rectangular en relación de aspecto fija que permite verificar la norma con los criterios de 5dB y 10dB de diferencias máximas de niveles directos en dicha fachada. En esta ponencia se detalla el procedimiento anterior. ABSTRACT. The Section "4.2 loudspeaker" of the UNE-EN ISO 140-5 International Standard: "Field measurements of airborne sound insulation of façade elements and façades", specifies that the directivity of the loudspeaker used in the test must ensure in all frequency bands of interest, local level differences less than 5dB (or 10dB for façade dimensions greater than 5m), measured in free field over an area of the same size and orientation as the wall or element to be tested. This requirement must be verified in the frequency bands of interest which are, at least, the third octave bands from 100Hz to 3150Hz, preferably from 50Hz to 5kHz. In recent years, in the Laboratory of Sound of the EUIT Telecomunicación (Universidad Politécnica de Madrid), the authors have implemented a method that, from directivity measurements of loudspeakers performed in the anechoic room, the direct sound field on a surface in the same layout as indicated in the ISO standard is calculated. It is also estimated the maximum horizontal dimension Δxmax of a rectangular façade for each aspect ratio which verify the standard criteria of either 5dB or 10dB for the maximum differences of direct levels in the façade. This paper details the procedure above introduced

New measurement methods for anechoic chamber characterization

As a continuation of the work presented in 122nd AES Convention, this paper tries to study in depth the anechoic chambers qualification. The purpose of this paper is to find parameters that allow the characterization of this type of enclosures. The proposal that becomes in this work is trying to obtain data of the anechoic chambers absorption by means of the transfer functions between pairs of microphones, or by means of the impulse response between pairs of microphones. Based on the results of the transfer functions between pairs of microphones can be checked easily agreement of the inverse squared law, allowing to determine the chamber cut-off frequency. Making a band-pass filtering it could be confirmed the anechoic chambers qualification

Estimation of Web Proxy Response Times in Community Networks Using Matrix Factorization Algorithms

Producción CientíficaIn community networks, users access the web using a proxy selected from a list, normally without regard to its performance. Knowing which proxies offer good response times for each client would improve the user experience when navigating, but would involve intensive probing that would in turn cause performance degradation of both proxies and the network. This paper explores the feasibility of estimating the response times for each client/proxy pair by probing only a few of the existing pairs and then using matrix factorization. To do so, response times are collected in a community network emulated on a testbed platform, then a small part of these measurements are used to estimate the remaining ones through matrix factorization. Several algorithms are tested; one of them achieves estimation accuracy with low computational cost, which renders its use feasible in real networks.Ministerio de Ciencia, Innovación y Universidades - Fondo Europeo de Desarrollo Regional (grants TIN2017-85179-C3-2-R and TIN2016-77836-C2-2-R)Generalitat de Catalunya (contract AGAUR SGR 990

Document sexuality and functional diversity. Sex and diverse, non-regulatory bodies as weapons of empowerment and political vindication in Yes we fuck!, Jo també vull sexe! and Crip Camp

El género documental es un cine subjetivo y reivindicativo que ha sido utilizado para prácticas activistas desde su creación, ampliando miradas, rompiendo tabúes y mostrando realidades diferentes, ricas y plurales. Los documentales Yes we fuck!, Jo també vull sexe! y Crip Camp tienen en común la visibilización del potencial político de los cuerpos en rebelión. En este artículo se realizará un estado de la cuestión acerca de la relación entre sexualidad y diversidad funcional para más adelante realizar un análisis audiovisual, con un enfoque cualitativo e interdisciplinar de los documentales seleccionados, poniendo especial énfasis en las transgresiones sociales que significa mostrar abiertamente las sexualidades y los cuerpos diversos. Entre los principales resultados, cabe destacar la forma en que el género documental aumenta el grado de empoderamiento personal y colectivo y termina convirtiéndose en un arma de reivindicación política.The documentary genre is a subjective and vindictive cinema that has been used for activist practices since its creation, broadening viewpoints, breaking taboos and showing different, rich and plural realities. The documentaries Yes we fuck!, Jo també vull sexe! and Crip Camp have in common the visibility of the political potential of bodies in rebellion. In this article, we will present a state of the art on the relationship between sexuality and functional diversity. We will then carry out an audiovisual analysis, with a qualitative and interdisciplinary approach, of the selected documentaries, placing special emphasis on the social transgressions that mean openly showing sexualities and diverse bodies. Among the main results, it is worth highlighting the way in which the documentary genre increases the degree of personal and collective empowerment and ends up becoming a weapon of political vindication

A self-scalable distributed network simulation environment based on cloud computing

Producción CientíficaWhile parameter sweep simulations can help undergraduate students and researchers to understand computer networks, their usage in the academia is hindered by the significant computational load they convey. This paper proposes DNSE3, a service oriented computer network simulator that, deployed in a cloud computing infrastructure, leverages its elasticity and pay-per-use features to compute parameter sweeps. The performance and cost of using this application is evaluated in several experiments applying different scalability policies, with results that meet the demands of users in educational institutions. Additionally, the usability of the application has been measured following industry standards with real students, yielding a very satisfactory user experience.Ministerio de Economía, Industria y Competitividad (Projects TIN2014-53199-C3-2-R and TIN2017-85179-C3-2-R)Junta de Castilla y León (programa de apoyo a proyectos de investigación - Ref. VA082U16

Online machine learning algorithms to predict link quality in community wireless mesh networks

Producción CientíficaAccurate link quality predictions are key in community wireless mesh networks (CWMNs) to improve the performance of routing protocols. Unlike other techniques, online machine learning algorithms can be used to build link quality predictors that are adaptive without requiring a predeployment effort. However, the use of these algorithms to make link quality predictions in a CWMN has not been previously explored. This paper analyses the performance of 4 well-known online machine learning algorithms for link quality prediction in a CWMN in terms of accuracy and computational load. Based on this study, a new hybrid online algorithm for link quality prediction is proposed. The evaluation of the proposed algorithm using data from a real large scale CWMN shows that it can achieve a high accuracy while generating a low computational load.Ministerio de Economía, Industria y Competitividad (Project TIN2014-53199-C3-2-R)Junta de Castilla y León (programa de apoyo a proyectos de investigación - Ref. VA082U16

Improving condition number and convergence of the surface integral-equation method of moments for penetrable bodies

Most of the surface integral equation (SIE) formulations for composite conductor and/or penetrable objects suffer from balancing problems mainly because of the very different scales of the equivalent electric and magnetic currents. Consequently, the impedance matrix usually has high- or ill-condition number due to the imbalance between the different blocks. Using an efficient left and right preconditioner the elements of the impedance matrix are balanced. The proposed approach improves the matrix balance without modifying the underlying SIE formulation, which can be selected solely in terms of accuracy. The numerical complexity of this preconditioner is O(N) with N the number of unknowns, and it can be easily included on any existing SIE code implementation.Ministerio de Ciencia e Innovación | Ref. TEC2011-28784-C02-01Ministerio de Ciencia e Innovación | Ref. TEC2011-28784-C02-0

Generating actionable predictions regarding MOOC learners’ engagement in peer reviews

Producción CientíficaPeer review is one approach to facilitate formative feedback exchange in MOOCs; however, it is often undermined by low participation. To support effective implementation of peer reviews in MOOCs, this research work proposes several predictive models to accurately classify learners according to their expected engagement levels in an upcoming peer-review activity, which offers various pedagogical utilities (e.g. improving peer reviews and collaborative learning activities). Two approaches were used for training the models: in situ learning (in which an engagement indicator available at the time of the predictions is used as a proxy label to train a model within the same course) and transfer across courses (in which a model is trained using labels obtained from past course data). These techniques allowed producing predictions that are actionable by the instructor while the course still continues, which is not possible with post-hoc approaches requiring the use of true labels. According to the results, both transfer across courses and in situ learning approaches have produced predictions that were actionable yet as accurate as those obtained with cross validation, suggesting that they deserve further attention to create impact in MOOCs with real-world interventions. Potential pedagogical uses of the predictions were illustrated with several examples.European Union’s Horizon 2020 research and innovation programme (Marie Sklodowska-Curie grant 793317)Ministerio de Ciencia, Innovación y Universidades (projects TIN2017-85179-C3-2-R / TIN2014-53199-C3-2-R)Junta de Castilla y León (grant VA257P18)Comisión Europea (grant 588438-EPP-1-2017-1-EL-EPPKA2-KA

Towards the Enactment of Learning Situations Connecting Formal and Non-Formal Learning in SLEs

Producción CientíficaSmart Learning Environments hold promise of adapting learning processes to the individual context of students and connecting formal with non-formal learning. To do so, SLEs need to know the current context of the students, regardless of the physical or virtual space where learning takes place. This paper presents an architecture that assists in the deployment and enactment of learning situations across-spaces, able to sense and react to changes in the students’ context in order to adapt the learning process.ICSLE 2019: International Conference on Smart Learning EnvironmentsAgencia Estatal de Investigación - Fondo Europeo de Desarrollo Regional (projects TIN2014-53199-C3-2-R / TIN2017-85179-C3-2-R)Comisión Europea (project 588438-EPP-1-2017-1-EL-EPPKA2-KA