Search results for "Computer Networks"
showing 10 items of 860 documents
Dipo : ciudad 'tartésico-turdetana' en el valle del Guadiana
2009
Los hallazgos de monedas de Dipo en el término de Guadajira, Badajoz, y el estudio territorial del Valle del Guadiana en época orientalizante han permitido localizar esta importante población de la antigua Lusitania. Su origen es una colonia tartésica, paralela y rival de Medellín-Conisturgis, pues ambas controlaban dos ramales paralelos de la 'Via de la Plata ' y la vía de Olisipo a Oretum, que unía todas las colonias periféricas del mundo tartesio septentrional.
An empirical evaluation of two natural hand interaction systems in augmented reality
2022
AbstractHuman-computer interaction based on hand gesture tracking is not uncommon in Augmented Reality. In fact, the most recent optical Augmented Reality devices include this type of natural interaction. However, due to hardware and system limitations, these devices, more often than not, settle for semi-natural interaction techniques, which may not always be appropriate for some of the tasks needed in Augmented Reality applications. For this reason, we compare two different optical Augmented Reality setups equipped with hand tracking. The first one is based on a Microsoft HoloLens (released in 2016) and the other one is based on a Magic Leap One (released more than two years later). Both d…
Perceptual adaptive insensitivity for support vector machine image coding.
2005
Support vector machine (SVM) learning has been recently proposed for image compression in the frequency domain using a constant epsilon-insensitivity zone by Robinson and Kecman. However, according to the statistical properties of natural images and the properties of human perception, a constant insensitivity makes sense in the spatial domain but it is certainly not a good option in a frequency domain. In fact, in their approach, they made a fixed low-pass assumption as the number of discrete cosine transform (DCT) coefficients to be used in the training was limited. This paper extends the work of Robinson and Kecman by proposing the use of adaptive insensitivity SVMs [2] for image coding u…
Los Estereotipos de género en las producciones audiovisuales: diseño y validación de la tabla de análisis EG_5x4
2022
Los productos culturales de la educación no formal, y en concreto los difundidos por televisión y plataformas streaming, incluidas no ficción y animación infantil, proponen entre sus figuraciones personajes estereotipados en su construcción de género. Según investigaciones previas, identificarlos y combatirlos favorece la erradicación de ideas sexistas relacionadas con violencias machistas. Por ello, el objetivo que se planteó fue diseñar y validar una tabla de análisis de estereotipos sexuales presentes en cualquier producto audiovisual. El proceso siguió un protocolo de 3 fases (Garrido et al., 2015): 1) Se revisó la literatura publicada, se extrajeron rasgos relacionados con estereotipos…
Vox and journalistic information: use and criticism of the media in the 2019 General Election campaigns
2022
The general elections held in 2019 gave Vox enough votes to enter the Spanish Parliament as the third most popular political party. The growing role of this radical right-wing party has revealed a complex relationship with the media. The objective of this study is to characterise the relationship between Vox and the media by analysing the party's electoral discourse using quantitative techniques – posts made on Facebook and Twitter (n = 224) – and qualitative techniques, exploring the framing used in the closing rallies of the campaign. References to the media dominated the messages Vox posted on Twitter during the November campaign, whose main purpose was to repost content previously broad…
Indoor localization using time difference of arrival with UWB signals and unsynchronized devices
2020
Abstract Indoor location using radio frequency (RF) signals has been traditionally focused mainly on RSSI and fingerprint techniques, because methods based on time of arrival (ToA) or time difference of arrival (TDoA) were not suitable for measuring short distances. However, the release of the IEEE 802.15.4a standard, the emergence of commercial ultra wide band (UWB) transceivers that are compliant to this norm and the integration of high frequency oscillators have permitted the design of more accurate indoor localization systems using the RF signal transmission time. In this paper, we propose an indoor localization system based on TDoA for UWB. The method implements an only one way transmi…
A study of LoRaWAN protocol performance for IoT applications in smart agriculture
2020
Abstract The use of Internet of Things (IoT) is becoming increasingly common in agribusiness to increase food production capacity for the expanding global population. Recently, low-power wide-area networks (LPWANs) have been used in the development of IoT applications that require low power consumption and low data transmission rates. LoRaWAN is considered the most suitable communication network for LPWANs for IoT applications in smart agriculture. In this paper, we present an in-depth study of the performance of the LoRaWAN communication network in the context of an IoT application for a pilot farm. We consider several scenarios and analyze simulation results by using Network Simulator 3. …
Design and performance evaluation of an hybrid reservation-polling MAC protocol for power-line communications
2003
This paper presents an hybrid reservation-polling MAC protocol able to effectively deal with the channel disturbances typical of Power-line communication systems. Channel access is controlled by a scheduler running on a centralized station. Fast retransmission of corrupted packets is employed to achieve high performance on Power-line channels characterized by frequent error bursts due to impulsive noise. The performance of our proposed mechanism are evaluated by means of simulation, for the more challenging case of time-sensitive traffic sources (voice calls). Results show that the system efficiency is virtually not affected by lightly to moderately disturbed PLC channel. Moreover, by sligh…
Resource allocation for clustered network MIMO OFDMA systems
2012
In this article, we address the resource allocation problem for the downlink of a large network multiple input multiple output orthogonal frequency division multiplexing system with 3-sector base stations. The system is statically divided into a number of disjoint clusters of sectors. A two-step resource allocation scheme is proposed involving the inter-cluster and the intra-cluster levels. As a first step or inter-cluster level, two cooperative frequency reuse approaches are designed to mitigate the inter-cluster interference. A user partition method is proposed to divide the users of each cluster into cluster-edge and cluster-center users. To balance the cell-edge and the cell-average per…
Energy-Efficient and Secure Resource Allocation for Multiple-Antenna NOMA with Wireless Power Transfer
2018
Non-orthogonal multiple access (NOMA) is considered as one of the promising techniques for providing high data rates in the fifth generation mobile communication. By applying successive interference cancellation schemes and superposition coding at the NOMA receiver, multiple users can be multiplexed on the same subchannel. In this paper, we investigate resource allocation algorithm design for an OFDM-based NOMA system empowered by wireless power transfer. In the considered system, users who need to transmit data can only be powered by the wireless power transfer. With the consideration of an existing eavesdropper, the objective is to obtain secure and energy efficient transmission among mul…