Studying the feasibility of a recommender in a citizen web portal based on user modeling and clustering algorithms
This paper presents a methodology to estimate the future success of a collaborative recommender in a citizen web portal. This methodology consists of four stages, three of them are developed in this study. First of all, a user model, which takes into account some usual characteristics of web data, is developed to produce artificial data sets. These data sets are used to carry out a clustering algorithm comparison in the second stage of our approach. This comparison provides information about the suitability of each algorithm in different scenarios. The benchmarked clustering algorithms are the ones that are most commonly used in the literature: c-Means, Fuzzy c-Means, a set of hierarchical …
Experimental trade-offs between different strategies for multihop communications evaluated over real deployments of wireless sensor network for environmental monitoring
Although much work has been done since wireless sensor networks appeared, there is not a great deal of information available on real deployments that incorporate basic features associated with these networks, in particular multihop routing and long lifetimes features. In this article, an environmental monitoring application (Internet of Things oriented) is described, where temperature and relative humidity samples are taken by each mote at a rate of 2 samples/min and sent to a sink using multihop routing. Our goal is to analyse the different strategies to gather the information from the different motes in this context. The trade-offs between ‘sending always’ and ‘buffering locally’ approac…
Thorough analysis of Raspberry Pi devices in outdoor/indoor communications in terms of QoS
The proliferation of commercial low-cost Small Board Computers (SBC) devices have allowed the deployment of many Wireless Sensor Networks (WSN) focused on different applications, mainly based on monitoring issues. These networks are characterized by a set of these SBCs devices working in a collaborative way where each device is sensing, processing and later sending out the data to the sink. These devices are equipped with power supply, a processing unit and communications capabilities (in particular WiFi), making themselves very interesting to fit in many topologies. However, their performance in terms of communications basically depends on the environment and usually heuristic techniques a…
Time synchronization enhancements in wireless networks with ultra wide band communications
The emergence of low cost Ultra Wide Band (UWB) transceivers has enabled the implementation of Wireless Sensor Networks (WSN) based on this communication technology. These networks are composed of distributed autonomous low cost nodes (also known as motes) with their own processing unit, memory and communications. Usually these nodes are power-limited and due to the poor performance and quality of their clocks, time synchronization is in the order of milliseconds and in some specific scenarios till microseconds. The integration of commercial UWB transceivers in these nodes can improve the synchronization accuracy. In particular, we focus on WSN nodes based on off-the-shelf commercial produc…
VentQsys: Low-cost open IoT system for CO2 monitoring in classrooms
AbstractIn educational context, a source of nuisance for students is carbon dioxide ($$CO_2$$ C O 2 ) concentration due to closed rooms and lack of ventilation or circulatory air. Also, in the pandemic context, ventilation in indoor environments has been proven as a good tool to control the COVID-19 infections. In this work, it is presented a low cost IoT-based open-hardware and open-software monitoring system to control ventilation, by measuring carbon dioxide ($$CO_2$$ C O 2 ), temperature and relative humidity. This system provides also support for automatic updating, auto-self calibration and adds some Cloud and Edge offloading of computational features for mapping functionalities. From…
MATLAB-based educational software for exploratory data analysis (EDA toolkit)
This article presents an educational software developed in order to enable engineering students to gain insight into data sets via the exploratory data analysis (EDA). This software has been developed using the MATLAB GUIDE tool. This article shows the program suitability for learning EDA in different engineering courses related to data analysis such as data mining or data processing courses. © 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 20: 313–320, 2012
Uso de Software-Defined Radio en la enseñanza de sistemas de comunicaciones
[ES] En la docencia de sistemas de comunicación hay una componente teórica elevada. La percepción de los estudiantes al estudiar estas asignaturas es negativa. Este trabajo trata de explicar la motivación y la estrategia seguida para reorientar esta percepción a partir de la introducción de elementos de “Software-Defined Radio” (SDR) y “Universal Software Radio Peripherals” (USRP) en diferentes asignaturas del Grado de Ingenier´ıa Telem´atica de la Universitat de València
Underwater Wireless Communications for Cooperative Robotics with UWSim-NET
The increasing number of autonomous underwater vehicles (AUVs) cooperating in underwater operations has motivated the use of wireless communications. Their modeling can minimize the impact of their limited performance in real-time robotic interventions. However, robotic frameworks hardly ever consider the communications, and network simulators are not suitable for HIL experiments. In this work, the UWSim-NET is presented, an open source tool to simulate the impact of communications in underwater robotics. It gathers the benefits of NS3 in modeling communication networks with those of the underwater robot simulator (UWSim) and the robot operating system (ROS) in modeling robotic systems. Thi…
Study of transmission parameters under controlled multipath environment using Rasp Pi3
The evaluation of QoS in mobile multipath environments is an interesting topic in modern communications. The use of Raspberry Pi as a low cost microcomputer board developed in the United Kingdom by the Raspberry Pi Foundation can be helpful in onsite deployments. The Pi3 model has integrated WiFi and Bluetooth connectivity and also 4 USB ports to expand the device with all kinds of peripheral. Under the premise of offering the power of a computer at low prices, this device is one of the most affordable ways to have a particularly efficient and dynamic hardware accessible at a low price to develop a Wireless Sensor Netwok (WSN). The use of the Raspberry Pi3 permits the development of a power…
Active learning in digital communications with low-cost software defined radio
Las comunicaciones digitales se enseñan tradicionalmente en sesiones de laboratorio desde un punto de vista teórico, utilizando plataformas de simulación. Sin embargo, el sistema de Acreditación Académica incluye la dimensión de "lo que se espera que los estudiantes sean capaces de hacer", lo que plantea la necesidad de disminuir la brecha entre las sesiones de laboratorio simuladas y un enfoque más práctico y realista. En este trabajo, proponemos una metodología para mejorar el aprendizaje de los aspectos prácticos relacionados con los cursos de Comunicaciones Digitales, así como para aumentar la motivación de los estudiantes, mediante el uso de dispositivos de radio definida por software …
Web mining based on Growing Hierarchical Self-Organizing Maps: Analysis of a real citizen web portal☆
This work is focused on the usage analysis of a citizen web portal, Infoville XXI (http://www.infoville.es) by means of Self-Organizing Maps (SOM). In this paper, a variant of the classical SOM has been used, the so-called Growing Hierarchical SOM (GHSOM). The GHSOM is able to find an optimal architecture of the SOM in a few iterations. There are also other variants which allow to find an optimal architecture, but they tend to need a long time for training, especially in the case of complex data sets. Another relevant contribution of the paper is the new visualization of the patterns in the hierarchical structure. Results show that GHSOM is a powerful and versatile tool to extract relevant …
Incorporando dispositivos de radio definida por software en la materia de Comunicaciones Digitales: del grupo piloto a la gran clase
[ES] La innovación educativa es un proceso que se extiende más allá de un curso académico. En su desarrollo se distinguen las etapas de planificación, implementación, evaluación y realimentación, para identificar aspectos susceptibles de mejora. En esta contribución presentamos el trabajo desarrollado en los dos últimos cursos en la asignatura Teoría de la Comunicación (materia de Comunicaciones Digitales), Grado en Ingeniería Telemática, de la Universitat de València. Concretamente, se incorporan dispositivos de radio definida por software en los laboratorios como herramienta para conseguir unas prácticas más realistas. El artículo describe el proceso de adaptación de una sesión de laboratori…
Development of a low-cost IoT system to detect and locate lightning strikes
Lightnings are violent natural phenomena and can generate many expenditures, specially when they strike in urban areas. The identification of the concrete geographic area where they strike is of critical importance for emergency services in order to enhance their effectiveness by doing an intensive coverage of the affected area. To achieve this aim, this paper proposes a design, prototype and validation of a distributed network of Internet of Things (IoT) devices to enable detection and location of lightning strikes. The IoT devices are empowered with lightning detection capabilities and are synchronized with the other devices in the sensor network. All of them cooperate within a network th…
Aprendizaje basado en proyectos en los laboratorios de comunicaciones digitales
[EN] Digital Communications and Signal Processing for Communications have been traditionally taught from a theoretical point of view. The complexity and cost of radio-frequency systems hampers the realization of practical experiences in the laboratories of Communications. However, current Academic Accreditation includes the dimension of “what students are expected to be able to do”. The decrease of the gap between standard simulated laboratory sessions and more practical and realistic approaches is therefore required. In this paper, we introduce an active learning methodology we have followed in order to introduce practical aspects related to Digital Communications and Signal Processing for…