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Computational Thinking is a competence that is developed more in the last few years. This is due to the multitude of benefits it has in the classroom. Throughout this article we show a series of activities that promote the development of Computational Thinking using tools that allow visual block programming. The particularity of these activities is that some of them were performed during the confinement due to the COVID-19 and other activities were performed later, in the period known as the new normality. Throughout the article, details are provided about the different sessions. The different visual programming tools by blocks and the educational scenarios used are also indicated. In addition, the results obtained are shown.

In this paper a model to track learning experiences from an interactive e-book is presented. For this a digital book coherent with the EPUB3 standards has been made by exporting an existing course in a learning management system and replicating its interactive behavior. Defining trigger points throughout the book and amongst the interactions made by the students, that send data to a learning record store, enrich the e-book and provide the possibility to analyze and preview statistical data for students’ commitment to learning the material and their actions over the whole course. The xAPI specification helps collect educational data and store it in a database, which can be used for creating a further set of reports anytime in the future.

This paper reports a novel telemetric smart bracket (TSB) for in vivo force/moment measurements during clinical orthodontic applications. The prototype implements a novel microcoil design resulting in a significant increase of the transmission distance compared to the previous state-of-the-art TSB. Using an automatic wirebonder, the microcoil is wound around an SU-8 post attached to the CMOS sensor wafer. For the first time, thus, 3D wirebonder-fabricated microcoils were integrated on a CMOS substrate, without compromising CMOS functionality. The augmented CMOS system serves here as a force/moment measurement device with six-degree-of-freedom ( $f_{x}, f_{y}, f_{z}, m_{x},\ m_{y},\ m_{z}$ ) functionality. The achieved transmission distance, i.e. coil-to-coil distance, was thereby increased by 80% compared to the best previous design to 5 mm, without the need for the system to exceed the severe size constraints of $2\times 2.8\times 1\ \mathrm{mm}^{3}$ defined by the bracket dimensions. The increased transmission distance allows uncritical contactless system powering and readout.

GaN technology has gained interest and is becoming widely commercially available due to their superior performances in power conversion applications. The paper shall promote the need for European GaN technology and boost R&D in the technological and reliability field for space. The paper will provide a clear overview on the technology, reliability, radiation, application and market.

This study analyzes a gamification experience in a Network Security Management subject of an Information Technology Engineering degree to evaluate whether the spaced-education methodology contributes to the learning improvement. The gamification experience is carried out by an automatic daily delivery of technical questions to students by e-mail.

The IEEE Educational Society has sponsored the development of IEEE-SA P1876™ standard for Networked Smart Learning Objects for Online Laboratories. This paper proposes two different architectures that integrate components to support educational online laboratories, through the use of xAPI statements to communicate between Remote Laboratory Management Systems, Virtual Learning Environments and Learning Analytics Generators. Proof of concept implementations of three scalable, ad hoc, low-cost, mobile, online laboratories that utilize the proposed distributed and centralized architectures are described, one fully integrated to an Actionable Data Book. The next steps would be to implement Mobile Massive Open Online Laboratories (M-MOOLs) within the context of Massive Open Online Courses (MOOCs), using the P1876™ standard under development.

In the process of searching for open educational resources, the use of ontologies is a key aspect in the reusability of resources for instructional purposes. In this paper, we address the issue of automatic tagging and classifying open educational resources by means of text mining techniques. The purpose is to set up a semantic framework in order to be used in the process of authoring educational material. Thus, authoring can be turned from a simple aggregation process into a dynamic and automatic selection of appropriate resources based on instructional needs and learning design.

We demonstrate a novel technique that provides a monitoring gain (relative to launch power) of up to 10 dB for in-service supervisory channels. Fast polarization spinning mitigates NL crosstalk which would otherwise instigate uncorrectable block errors in FEC-supported PolMux signals. The method simplifies interoperability of terminal equipment in Open Cable Systems.

Virtual oscillator control (VOC) and droop control are distinct methods to ensure synchronization and power sharing of parallel inverters in islanded systems. VOC is a control strategy where the dynamics of a nonlinear oscillator are used to derive control states to modulate the switch terminals of an inverter. Since VOC is a time-domain controller that reacts to instantaneous measurements with no additional filters or computations, it provides a rapid response during transients and stabilizes volatile dynamics. In contrast, droop control regulates the inverter voltage in response to the measured average real and reactive power output. Given that real and reactive power are phasor quantities that are not well-defined in real time, droop controllers typically use multiplicative operations in conjunction with low-pass filters on the current and voltage measurements to calculate such quantities. Since these filters must suppress low frequency ac harmonics, they typically have low cutoff frequencies that ultimately impede droop controller bandwidth. Although VOC and droop control can be engineered to produce similar steady-state characteristics, their dynamic performance can differ markedly. This paper presents an analytical framework to characterize and compare the dynamic response of VOC and droop control. The analysis is experimentally validated with three 120 V inverters rated at 1kW, demonstrating that for the same design specifications VOC is roughly 8 times faster and presents almost no overshoot after a transient.

We present a decentralized control strategy that yields switch interleaving among parallel-connected dc-dc buck converters. The proposed method is based on the digital implementation of the dynamics of a nonlinear oscillator circuit as the controller. Each controller is fully decentralized, i.e., it only requires the locally measured output current to synthesize the pulse width modulation (PWM) carrier waveform and no communication between different controllers is needed. By virtue of the intrinsic electrical coupling between converters, the nonlinear oscillator-based controllers converge to an interleaved state with uniform phase-spacing across PWM carriers. To the knowledge of the authors, this work presents the first fully decentralized strategy for switch interleaving in paralleled dc-dc buck converters.

This paper presents the main results achieved in the program eMadrid Program in Open Educational Resources, Free Software, Open Data, and about formats and standardization of content and services. © 2016 IEEE.

This article describes in detail the main achievements in authoring and reuse of educational materials within the eMadrid project.

The use of Information and Communication Technologies (IT) in education has helped strengthen the process of teaching and learning in several aspects. One specific interest is to increase spreading out learning programming to basic education, as a method to improve the development of different cognitive abilities, such as problem solving, abstraction, logical thinking, between others. In order to make IT a route to improve basic education in Mexico, the federal government has implemented the MiCompu.mx program, as a mean to promote, in young students, the use of TI as a driver of improved academic performance. Taking advantage of this situation, in this study, we use the technological infrastructure of MiCompu.mx program as a base to implement a strategy for teaching programming in basic public education, assuming that, in this way, students' general achievement can be improved, and the interest of students studying careers related to technology can be increased.

The arrival of new electronic devices and high-speed Internet connections have provoked a revolution on the Web design, introducing new concepts as responsive web and OneWeb. Web developments should be able to adapt to any device. Applying these concepts it has been created a web application called "Formulas App", which is a perfect complement for enriching learning scenarios, mainly dictated to science fields such as physics, mathematics or electronics. Such application provides added value to virtual and remote laboratories, PDF files, videos or education tools, such as quizzes, forums or chats. In addition all of them could be integrated inside Learning Management Systems (LMS) and Personal Learning Environment (PLE) and create complete and efficient learning scenarios, scaffoldings.

Universities and educational organizations or institutions, when designing any electronics course, trust in experimentation through laboratory practices in order to build successful cross-curricular capabilities and capacities. In electronics courses there is a need to have practical experiences, the benefits of electronics laboratory practices are widely known for professionals and necessary for any person who seeks for a broad comprehension of the real-time performance beyond the ideal modelling. Therefore, when designing any electronics course, the laboratory practices are one of the pillars on which the learning is established. Distance education has become widespread in the last decade and has fostered lifelong learning and continuing education patterns, allowing access to learning resources at any time and from everywhere. It has been possible thanks to the internet development and technologies associated with learning tools for a new teaching pedagogy. To support life-long learning and students' autonomous learning activities, remote experimentation has become a challenge in electronics courses; rather, the way the universities and educational organizations or institutions deliver remote experimentation to students in distance learning environments, has become a challenge. Nowadays, there is an extensive variety for providing theoretical contents in distance learning (videos, documents, tutorials, scaffolding activities, peer-to-peer reviews, forums, etc.) to students. These tools, by an efficiently and appropriate selection from professors and use from students, can complement or replace successfully in-person education, even they can reach some aspects that in-person education cannot achieve. Unfortunately, practical issues are not as developed as theoretical ones are. A first approach to this problem is clearly the use of simulators and virtual labs. Although, they are still a bit far from providing to student the real performance and features of equipment under real-life operation conditions. The major challenge is the provision of laboratory working online along with the theoretical contents in a massive context.

Power-management techniques can be effective at squeezing more performance and energy efficiency out of mature SoCs. Vmax reliability limits, infrastructure limits, guard-bands, aging, and thermal limits all put restrictions on performance. This paper describes five power-management techniques that provide a net performance increase of up to 15%, depending on the application and TDP of the SoC, on “Bristol Ridge”, a 28nm CMOS dual-core x86 APU.

This paper discusses how usage patterns and preferences of inhabitants can be learned efficiently to allow smart homes to autonomously achieve energy savings. We propose a frequent sequential pattern mining algorithm suitable for real-life smart home event data. The performance of the proposed algorithm is compared to existing algorithms regarding completeness/correctness of the results, run times as well as memory consumption and elaborates on the shortcomings of the different solutions. We also propose a recommender system based on the developed algorithm. This recommender provides recommendations to the users to reduce their energy consumption. The recommender system was deployed to a set of test homes. The test participants rated the impact of the recommendations on their comfort. We used this feedback to adjust the system parameters and make it more accurate during a second test phase. The historical dataset provided by digitalSTROM contained 33 homes with 3521 devices and over 4 million events. The system produced 160 recommendations on the first phase and 120 on the second phase. The ratio of useful recommendations was close to 10%.

This paper presents a case study of a recommender system that can be used to save energy in smart homes without lowering the comfort of the inhabitants. We present an algorithm that mines consumer behavior data only and applies machine learning to suggest actions for inhabitants to reduce the energy consumption of their homes. The system looks for frequent and periodic patterns in the event data provided by the digitalSTROM home automation system. These patterns are converted into association rules, prioritized and compared with the current behavior of the inhabitants. If the system detects opportunities to save energy without decreasing the comfort level, it sends a recommendation to the inhabitants. The system was implemented and deployed to a set of test homes. The test participants were able to rate the impact of the recommendations on their comfort. This feedback was used to adjust the system parameters and make it more accurate during a second test phase. The historical data set provided by digitalSTROM contained 33 homes with 3521 devices and over 4 million events. The system produced 160 recommendations on the first phase and 120 on the second phase. The ratio of useful recommendations was close to 10%. We found out that a recommender system that uses an algorithm that mines patterns based on their confidence, independent of their frequency and periodicity, might achieve better results and a higher acceptance by users.

This paper describes very high frequency (10–200 MHz) switched-mode power converters using custom GaN chips with integrated power switches and gate drivers, allowing standard logic-level PWM control inputs. Circuit design techniques are described in depletion-mode 0.15μm RF and 0.25μm switch GaN-on-SiC processes, including integration of gate-drive and level translation circuits. Operating from up to 25 V dc input voltage, efficiencies exceeding 90% are demonstrated at switching frequencies up to 100 MHz and at power levels exceeding 10 W. When used as an envelope-tracking drain supply modulator for high-efficiency RF transmitters, a monolithic two-phase 25 V, 10 W GaN converter prototype achieves 20 MHz large-signal tracking bandwidth with 89.7% average power-stage efficiency.

Supply modulation is a system efficiency improvement technique in radio-frequency (RF) transmitters, where a power converter operating as an envelope tracking (ET) amplifier serves as the power supply for an RF power amplifier. This paper presents design of higher-order output filters in multi-phase buck ET amplifiers to achieve wide-bandwidth tracking with high efficiency using zero-voltage switching (ZVS) technique. The approach is verified by experiments on two-phase GaN-based ET prototypes operating at 10 MHz and 50 MHz per-phase switching frequency, and having fourth-order filters with 5 MHz and 20 MHz tracking bandwidth, respectively. Experimental results demonstrate accurate tracking of 2.4 MHz and 20 MHz bandwidth LTE envelope signals with 93.2% and 89.7% power-stage efficiency, respectively.

Fundamental resonance modes of nanocrescent optical antennas are associated with large electric fields at the crescent tips. These antennas have been extensively studied due to their relative ease of fabrication and tunable response via methods such as nanosphere template lithography. To date, investigations have only been performed in the visible to mid-infrared range, where the multimode anisotropic response has been documented both experimentally and through simulations. However, the presence of interband transitions in the dielectric response of the metals used for these studies complicates the analysis of the higher-order resonance modes. In this paper, we perform a comprehensive investigation of the electromagnetic response of aluminum nanocrescent antennas. Aluminum has an interband transition in the near-infrared that facilitates scaling of the resonance modes into the ultraviolet part of the spectrum, thus, allowing investigation of the higher-order modes of the nanocrescent structure. These high...

This paper describes three driver options for integrated half-bridge power stage using depletion-mode GaN-on-SiC 0.15μm RF process: an active pull-up driver, a bootstrapped driver, and a modified active pull-up driver. The approaches are evaluated and compared in 5 W, 20 V synchronous Buck converter prototypes operating at 100 MHz switching frequency over a wide range of operating points. Measured efficiency peaks above 91% for the designs using the bootstrap and the modified active pull-up integrated drivers.

The use of techniques such as envelope tracking (ET) and envelope elimination and restoration (EER) can improve the efficiency of radio frequency power amplifiers (RFPA). In both cases, high-bandwidth DC/DC converters called envelope amplifiers (EA) are used to modulate the supply voltage of the RFPA. This paper addresses the analysis and design of a modified two-phase Buck converter optimized to operate as EA. The effects of multiphase operation on the tracking capabilities are analyzed. The use of a fourth-order output filter is proposed to increase the attenuation of the harmonics generated by the PWM operation, thus allowing a reduction of the ratio between the switching frequency and the converter bandwidth. The design of the output filter is addressed considering envelope tracking accuracy and distortion caused by the side bands arising from the nonlinear modulation process. Finally, the proposed analysis and design methods are supported by simulation results, as well as demonstrated by experiments obtained using two 100-W, 10-MHz, two-phase Buck EAs capable of accurately tracking a 1.5-MHz bandwidth OFDM signal, Spanish Ministry of Education and Science under Consolider Project [RUE CSD2009-00046, DPI2010-21110-C02-0]; European Regional Development Fund (ERDF) Grants

This paper presents a new educational system to automatically adapt the evaluation activities to the students' needs in the context of Higher Engineering Education. As an example, a subject focused on the configuration of network services has been chosen to implement our proposal. Therefore, the system will be able to guide each student through the learning process based on his/her particular knowledge-level. In addition to this, specific techniques are needed to dynamically evolve the system depending on the students' progress. In our case, this is analyzed by using data mining techniques. Finally, we show survey results, which illustrate the ease of use and usefulness of the system.

GaN-on-SiC technology has been widely used in radiofrequency (RF) power amplifiers to achieve high power density at very high frequencies due to the enhanced power handling capabilities provided by the SiC substrate and very high transition frequencies of GaN High Electron Mobility Transistors (HEMTs). Along with other well-known advantages of GaN, such as high breakdown voltage and high temperature operation, these characteristics make GaN-on-SiC technology suitable for power electronics applications. This paper explores the use of GaN-on-SiC depletion-mode HEMTs in switched-mode power converters, targeting high efficiencies at switching frequencies in the tens of Megahertz range. The fundamental limits of the technology are analyzed, and design principles and guidelines are given to exploit the capabilities of the devices. Results are presented for a 10 W, 20 V synchronous Buck converter prototype operating at 10 to 40 MHz. Measured efficiency peaks above 96% at 10 MHz and remains above 90% over a wide range of operating conditions. To demonstrate the applicability of the technology, the Buck converter switching at 20 MHz is used as a supply modulator to track a 3 MHz envelope signal with greater than 90% average efficiency.

Design of implantable antennas poses a unique set of challenges since antennas need to be small, biocompatible, and operate in the highly lossy environment of the human body. A recent review identified miniaturization challenges and how they have been managed in a variety of designs. [1] It also noted the sensitivity of these miniaturized antennas to fabrication tolerances. Our paper addresses another type of challenge - effective methods to manufacture these antennas using biocompatible materials (many of which are difficult to adhere with glue or solder), tight manufacturing tolerances (and practical ways to manage them), and a design that is practical both for manufacturing of individual test antennas by hand or for larger scale manufacturing. We will build on the spiral microstrip designs originally presented in [2] and expanded in [3][4].

This paper presents an envelope tracking supply modulator for a high efficiency radiofrequency power amplifier (RFPA). A wide bandwidth linear amplifier using a GaN high electron mobility transistor (HEMT) as a source follower output stage is described. A low bandwidth, high efficiency current controlled Buck converter is used to assist the linear amplifier and improve the system efficiency. Steps towards integration of the supply modulator and the RFPA are given through inclusion of the modulator output stage with an RFPA on a microwave monolithic integrated circuit (MMIC). Simulation and experimental results are presented for a 150 MHz bandwidth, 9 V to 27 V output voltage modulator supplying a 10 GHz RFPA.

Assessment and evaluation of students' performance has always played an important role in the learning process as it provides information about the level of knowledge acquired on a subject, and the progress that has been achieved. However, another main issue is detecting the thematic core in which the students have learning problems because they are evaluated in terms of competencies. This study proposes an adaptive approach to diagnose and feedback students, and makes use of the Item Response Theory to estimate skill levels and classify the students. In addition, it uses a model of concepts' relationship between the concepts and the items of the test. The purpose is to diagnose students' cognitive problems and provide personalized and intelligent learning suggestions. This approach can be used as a system of intelligent diagnosis that receives a set of responses, and generates a data set of weak concepts for each student, specifying their learning path and resulting in clustering individuals who share the same shortcomings to ease any process of group feedback.

Merging a Learning Management System (LMS) and a social network has social advantages for students. Among others, students can show off their achievements among their acquaintances, which in turn improves their social leadership and self-esteem. This is specially true in the case of distance learning, where there are no physical interactions between students, so their student life is totally isolated from their everyday life (e.g. students do not go out together, since they may live in different cities or even countries although they study the same subjects). All these points suggest that the use of social networks for distance teaching has clear advantages that can be harnessed. In order to achieve the aforementioned benefits, we are working on integrating a commonly used LMS, Moodle, into one of the most widely-used social network, Facebook. This integration allows students and faculty to use Facebook as a communication tool that improves the learning process and social life of students in the ways presented before.

The final radiofrequency power amplifier (PA) of a radar transmitter module is a large factor in system efficiency. Typical radar transmitter signals are frequency-modulated with constant-amplitude pulse envelopes in order to optimize efficiency, resulting in spectral broadening and power radiated outside of the radar frequency band. This paper demonstrates a PA with a dynamic power supply which enables high efficiency while reducing the spectral emissions. The resonant pulse-shaping power supply generates a raised-cosine pulse envelope waveform with efficiency greater than 90% and peak envelope power around 6 W. Measured results with a 2.14-GHz GaN power amplifier with an efficiency of 76% at peak power demonstrate over 67% transmitter efficiency.

This paper describes a very simple Digital Pulse Width Modulator (DPWM), with under 100 picoseconds resolution capability in low-cost field-programmable gate arrays (FPGA). The DPWM implementation is based on internal carry chains and internal logic resources which are present in most FPGA families. The proposed approach does not require manual routing or placement, consumes few hardware resources, and does not rely on specialized phase locked loop or clock management resources. The DPWM is capable of supporting high switching frequencies for digitally controlled switched-mode power converters. A 50 MHz switching frequency DPWM with 60 picoseconds resolution and a 1 MHz switching frequency DPWM with 90 picoseconds resolution are experimentally demonstrated, with monotonicity and excellent linearity.

Increasing the efficiency of Radio Frequency Power Amplifiers has growth in importance due to the widespread use of wireless communications. Efficiency enhancement techniques such as Envelope Tracking and Envelope Elimination and Restoration use DC/DC converters to track the envelope of the signals being transmitted. These envelopes often have very high bandwidth and slew rate, challenging the design of fast and efficient tracking converters. Furthermore, traditional second order output filter design techniques applied to tracking converters lead to very high switching frequencies and thus low efficiencies. This paper analyzes the use of higher order filters to improve the dynamic response of tracking converters without increasing the switching frequency, thus maintaining high efficiency operation. This approach can be combined with a multiphase architecture to further increase the achievable bandwidth. Experimental results that demonstrate the effectiveness of the proposed approach are shown using a 2-phase multiple-input buck converter operating in open loop with a fourth order Bessel output filter.