Uso de TGT y aprendizaje cooperativo para promover un aprendizaje activo de los alumnos

[Resumen] En el grado de Ingeniería Informática la mayoría de asignaturas presentan un enfoque práctico, donde se combina la resolución de problemas con prácticas basadas en TIC. Sin embargo, las clases magistrales siguen un enfoque más clásico donde el alumno es un mero agente pasivo que se limita a escuchar las explicaciones del docente. La monotonía de las clases magistrales contribuye a que el alumno pierda rápidamente, la atención y el interés por la asignatura. En este trabajo se describe un enfoque basado en metodologías activas que busca promover la participación de los alumnos en las clases magistrales e involucrarlos de forma más activa en su proceso de aprendizaje. La metodología propuesta se basa en la idea de los Team Game Tournaments (TGT) apoyada en el uso de estrategias de Aprendizaje Cooperativo (AC). Los estudiantes se organizan en pequeños grupos, de forma que cada estudiante debe preparar individualmente una parte del tema correspondiente. En la siguiente clase, cada estudiante explica a sus compañeros su parte y en conjunto elaboran una lista de preguntas para todo el tema. Finalmente, se organiza una batalla de preguntas donde cada grupo formula sus preguntas a otros grupos siguiendo una dinámica similar a la de los concursos culturales. La evaluación final consiste en una evaluación individual donde se valoran habilidades relacionadas con el trabajo en equipo, y en una evaluación del grupo que tiene en cuenta la adecuación de las preguntas elaboradas por el grupo y el resultado obtenido en la batalla de preguntas. Esta metodología se fundamenta en la premisa de que el aprendizaje del estudiante es más significativo cuando tiene que explicar lo aprendido a sus compañeros y, por otro lado, en la idea de que metodologías basadas en TGT ayudan a fomentar la competitividad entre alumnos, mejorar su implicación en la asignatura y promover la interdependencia positiva. Los resultados obtenidos muestran un alto grado de satisfacción de los estudiantes con esta nueva metodología y que ésta les ha ayudado a lograr un aprendizaje más profundo y mejorar su motivación a la hora de preparar la asignatur

Transmission of Spatio-Temporal Correlated Sources Over Fading Multiple Access Channels With DQLC Mappings

© 2019 IEEE. This version of the article has been accepted for publication, after peer review. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. The Version of Record is available online at: https://doi.org/ 10.1109/TCOMM.2019.2912571.[Abstract]: The design of zero-delay Joint Source-Channel Coding (JSCC) schemes for the transmission of correlated information over fading Multiple Access Channels (MACs) is an interesting problem for many communication scenarios like Wireless Sensor Networks (WSNs). Among the different JSCC schemes so far proposed for this scenario, Distributed Quantizer Linear Coding (DQLC) represents an appealing solution since it is able to outperform uncoded transmissions for any correlation level at high Signal-to-Noise Ratios (SNRs) with a low computational cost. In this paper, we extend the design of DQLC-based schemes for fading MACs considering sphere decoding to make the optimal Minimum Mean Squared Error (MMSE) estimation computationally affordable for an arbitrary number of transmit users. The use of sphere decoding also allows to formulate a practical algorithm for the optimization of DQLC-based systems. Finally, non-linear Kalman Filtering for the DQLC is considered to jointly exploit the temporal and spatial correlation of the source symbols. The results of computer experiments show that the proposed DQLC scheme with the Kalman Filter decoding approach clearly outperforms uncoded transmissions for medium and high SNRs.This work has been funded by Office of Naval Research Global of United States (N62909-15-1-2014), the Xunta de Galicia (ED431C 2016-045, ED341D R2016/012, ED431G/01), the Agencia Estatal de Investigación of Spain (TEC2015-69648-REDC, TEC2016-75067-C4-1-R) and ERDF funds of the EU (AEI/FEDER, UE).United States. Office of Naval Research Global of United States; N62909-15-1-2014Xunta de Galicia; ED431C 2016-045Xunta de Galicia; ED341D R2016/012Xunta de Galicia; ED431G/0

Transmission of Analog Information Over the Multiple Access Relay Channel Using Zero-Delay Non-Linear Mappings

[Abstract]: We consider the zero-delay encoding of discrete-time analog information over the Multiple Access Relay Channel (MARC) using non-linear mapping functions. On the one hand, zero-delay non-linear mappings are capable to deal with the multiple access interference (MAI) caused by the simultaneous transmission of the information. On the other, the relaying operation is a Decode-and-Forward (DF) strategy where the decoded messages are merged into a single message using a specific continuous mapping depending on the correlation level of the source information. At the receiver, an approximated Minimum Mean Squared Error (MMSE) decoder is developed to obtain an estimate of the transmitted source symbols which exploits the information received from the relay node in combination with the messages received from the transmitters through the direct links. The resulting system provides better performance than the other alternative encoding strategies for the MARC with similar complexity and delay and also approaches the performance of theoretical strategies which require a significantly higher delay and computational cost.This work was supported in part by the Office of the Naval Research Global of United States under Grant N62909-15-1-2014, in part by the Xunta de Galicia under Grant ED431C 2016-045, Grant ED341D R2016/012, and Grant ED431G/01, in part by the Agencia Estatal de Investigación of Spain under Grant TEC2015-69648-REDC and Grant TEC2016-75067-C4-1-R, and in part by the ERDF funds of the EU (AEI/FEDER, UE).Xunta de Galicia; ED431C 2016-045Xunta de Galicia; ED341D R2016/012Xunta de Galicia; ED431G/0

Analog Transmission of Spatio-Temporal Correlated Sources Over MAC With Modulo Mappings

© 2018 IEEE. This version of the article has been accepted for publication, after peer review. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. The Version of Record is available online at: https://doi.org/10.1109/LCOMM.2018.2807427[Abstract]: Modulo mappings is an appealing scheme for the analog transmission of spatially correlated discrete-time analog source symbols over multiple access channels. In this letter, we show that the modulo mappings are also useful to exploit temporal correlation with zero-delay and without impairing encoding/decoding computational complexity. Spatio-temporal source correlation is exploited with a Kalman filter-based receiver, coupled with a sphere decoder, that takes into account the non-linearities of the modulo mappings. We also explain how to optimize the mapping parameters.This work has been funded by Office of Naval Research Global of United States (N62909-15-1-2014), the Xunta de Galicia (ED431C 2016-045, ED341D R2016/012, ED431G/01), the Agencia Estatal de Investigación of Spain (TEC2015-69648-REDC, TEC2016-75067-C4-1-R) and ERDF funds of the EU (AEI/FEDER, UE). The authors thank Prof. Joaquín Míguez of Universidad Carlos III de Madrid, Spain, for his helpful suggestions.Xunta de Galicia; ED431C 2016-045Xunta de Galicia; ED341D R2016/012Xunta de Galicia; ED431G/01United States. Office of Naval Research Global of United States; N62909-15-1-201

A Rank-Constrained Coordinate Ascent Approach to Hybrid Precoding for the Downlink of Wideband Massive (MIMO) Systems

© 2023 IEEE. This version of the article has been accepted for publication, after peer review. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. The Version of Record is available online at: https://doi.org/10.1109/TVT.2023.3293933.[Abstract]: An innovative approach to hybrid analog-digital precoding for the downlink of wideband massive MIMO systems is developed. The proposed solution, termed Rank-Constrained Coordinate Ascent (RCCA), starts seeking the full-digital precoder that maximizes the achievable sum-rate over all the frequency subcarriers while constraining the rank of the overall transmit covariance matrix. The frequency-flat constraint on the analog part of the hybrid precoder and the non-convex nature of the rank constraint are circumvented by transforming the original problem into a more suitable one, where a convenient structure for the transmit covariance matrix is imposed. Such structure makes the resulting full-digital precoder particularly adequate for its posterior analog-digital factorization. An additional problem formulation to determine an appropriate power allocation policy according to the rank constraint is also provided. The numerical results show that the proposed method outperforms baseline solutions even for practical scenarios with high spatial diversity.Xunta de Galicia; ED431C 2020/15Xunta de Galicia; ED431G 2019/01This work has been supported in part by grants ED431C 2020/15 and ED431G 2019/01 (to support the Centro de Investigación de Galicia “CITIC”) funded by Xunta de Galicia and ERDF Galicia 2014-2020, and by grants PID2019-104958RB-C42 (ADELE) and PID2020-118139RB-I00 funded by MCIN/AEI/10.13039/501100011033. The authors thank the Defense University Center at the Spanish Naval Academy (CUD-ENM) for all the support provided for this research

Rank Constrained Precoding for the Downlink of mmWave Massive MIMO Hybrid Systems

[Abstract] The hybrid design of precoding schemes for millimeter-wave communications allows exploiting the gains by using large antenna array with an affordable hardware cost and power consumption. In this work, we present a novel design strategy based on limiting the rank of the fully digital solutions before their decomposition into the analog and digital baseband components. This rank constraint on the digital formulation leads to a joint precoding and scheduling scheme where the number of allocated streams is limited according to the hardware constraints. In this way, the proposed approach can significantly reduce the performance losses caused by the direct decomposition of the unconstrained digital precoders. The resulting rank-constrained problems for the considered scenario are not convex and difficult to sort out. However, we propose several algorithms to compute the rank-constrained digital solutions with the help of the uplink-downlink duality for the achievable sum-rate. The obtained results show that this strategy achieves considerably higher sum-rates regardless of the channel conditions or available hardware resources.10.13039/501100010801-Xunta de Galicia (Grant Number: ED431C 2020/15 and ED431G2019/01) Centro de Investigación de Galicia “CITIC” 10.13039/501100011033-Agencia Estatal de Investigación of Spain (Grant Number: RED2018-102668-T and PID2019-104958RB-C42) 10.13039/501100008530-European Regional Development Fund (ERDF) of the EU (FEDER Galicia 2014-2020 & AEI/FEDER Programs, UE)Xunta de Galicia; ED431G 2019/01Xunta de Galicia; ED431C 2020/1

PICTOTEMPO: An App for Personal Organization in Autism Spectrum Disorders

Presented at the 4th XoveTIC Conference, A Coruña, Spain, 7–8 October 2021.[Abstract] In this work, we develop a mobile application which allows to create digital schedules for children with autism spectrum disorder. These schedules comprise a sorted sequence of tasks or activities which facilitates children to understand and anticipate the upcoming events, thus reducing their stress and frustration. For that, the activities are identified and described with the help of visual supports (pictograms) which can be visualized on the screen of any mobile device. The developed application also allows to gather valuable information about the performance and interests of the children from their interactions with it, helping to refine and define more appropriate routines or support therapies for the children. In this way, the aim of this work is to contribute to improve the lives of people with functional and cognitive diversity, especially children with these disorders, and also their families.This work has been funded by the Xunta de Galicia (by grant ED431C 2020/15, and grant ED431G 2019/01 to support the Centro de Investigación de Galicia “CITIC”), the Agencia Estatal de Investigación of Spain (by grants RED2018-102668-T and PID2019-104958RB-C42) and ERDF funds of the EU (FEDER Galicia 2014-2020 & AEI/FEDER Programs, UE)Xunta de Galicia; ED431C 2020/15Xunta de Galicia; ED431G 2019/0

Lattice-Based Analog Mappings for Low-Latency Wireless Sensor Networks

© 2023 IEEE. This version of the article has been accepted for publication, after peer review. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. The Version of Record is available online at: https://doi.org/10.1109/JIOT.2023.3273194.[Abstract]: We consider the transmission of spatially correlated analog information in a wireless sensor network (WSN) through fading single-input and multiple-output (SIMO) multiple access channels (MACs) with low-latency requirements. A lattice-based analog joint source-channel coding (JSCC) approach is considered where vectors of consecutive source symbols are encoded at each sensor using an n -dimensional lattice and then transmitted to a multiantenna central node. We derive a minimum mean square error (MMSE) decoder that accounts for both the multidimensional structure of the encoding lattices and the spatial correlation. In addition, a sphere decoder is considered to simplify the required searches over the multidimensional lattices. Different lattice-based mappings are approached and the impact of their size and density on performance and latency is analyzed. Results show that, while meeting low-latency constraints, lattice-based analog JSCC provides performance gains and higher reliability with respect to the state-of-the-art JSCC schemes.This work was supported in part by the Xunta de Galicia under Grant ED431C 2020/15, and in part by MCIN/AEI/10.13039/501100011033 and the European Union NextGenerationEU/PRTR under Grant PID2019-104958RB-C42 (ADELE), Grant TED2021-130240B-I00 (IVRY), and Grant BES-2017-081955. CITIC is funded by Xunta de Galicia through the collaboration agreement between the Consellería de Cultura, Educación, Formación Profesional e Universidades, and the Galician universities for the strengthening of the research centers of the Galician University System (CIGUS).Xunta de Galicia; ED431C 2020/1

Deep Contextual Bandit and Reinforcement Learning for IRS-Assisted MU-MIMO Systems

© 2023 IEEE. This version of the article has been accepted for publication, after peer review. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. The Version of Record is available online at: https://doi.org/10.1109/TVT.2023.3249353.[Abstract]: The combination of multiple-input multiple-output (MIMO) systems and intelligent reflecting surfaces (IRSs) is foreseen as a critical enabler of beyond 5G (B5G) and 6G. In this work, two different approaches are considered for the joint optimization of the IRS phase-shift matrix and MIMO precoders of an IRS-assisted multi-stream (MS) multi-user MIMO (MU-MIMO) system. Both approaches aim to maximize the system sum-rate for every channel realization. The first proposed solution is a novel contextual bandit (CB) framework with continuous state and action spaces called deep contextual bandit-oriented deep deterministic policy gradient (DCB-DDPG). The second is an innovative deep reinforcement learning (DRL) formulation where the states, actions, and rewards are selected such that the Markov decision process (MDP) property of reinforcement learning (RL) is appropriately met. Both proposals perform remarkably better than state-of-the-art heuristic methods in scenarios with high multi-user interference.This work has been supported by grants ED431C 2020/15 and ED431G 2019/01 (to support the Centro de Investigación de Galicia “CITIC”) funded by Xunta de Galicia and ERDF Galicia 2014-2020; and by grants PID2019-104958RB-C42 (ADELE) and BES-2017-081955 funded by MCIN/AEI/10.13039/501100011033.Xunta de Galicia; ED431C 2020/15Xunta de Galicia; ED431G 2019/0

User Grouping for the Uplink of Multiuser Hybrid mmWave MIMO

[Abstract] Hybrid analog/digital schemes for precoding/combining have proved to be a low-complexity and/or low-power strategy to obtain reasonable beamforming gains in multiuser millimeter-wave (mmWave) multiple-input multiple-output (MIMO) systems. Hybrid precoding/combining performs jointly baseband processing and analog processing in the radio frequency (RF) domain. In these systems, the number of RF chains limits the maximum number of streams simultaneously handled by the transceivers. In the uplink of a multiuser mmWave MIMO system, the hardware reduction based on hybrid transceivers is limited by the number of data streams that must be simultaneously served by the centralized node. Most works approach hybrid transceiver design by considering more RF chains than data streams, an unrealistic assumption when the number of nodes is large. On the other hand, statistically independent information is conventionally assumed in multiuser mmWave systems. This assumption does not hold in scenarios like wireless sensor networks (WSNs), where the sources produce correlated information. In this paper, by enabling inter-user correlation exploitation, we propose a grouping approach to handle a high number of individual sources with a limited number of RF chains through distributed quantizer linear coding (DQLC) mappings. The allocation of the users per group and the hybrid design of the combiner at the common central node to serve the grouped users is also analyzed. We also propose a hybrid minimum mean square error (MMSE) combining design in order to exploit the spatial correlation between the sources in a conventional uncoded mmWave uplink. Simulation results show the performance advantages of the proposed approaches in various hardware-constrained system settings.10.13039/501100010801-Xunta de Galicia (Grant Number: ED431G2019/01) 10.13039/501100011033-Agencia Estatal de Investigaci??n (Grant Number: TEC2016-75067-C4-1-R, RED2018-102668-T and PID2019-104958RB-C42) BES-2017-081955Xunta de Galicia; ED431G2019/0