Search results for "Computer network"

Estado de la investigación sobre la colaboración en Entornos Virtuales de Aprendizaje

2019

El aprendizaje colaborativo posee una tradición teórica y práctica amplia en la educación general, como en la educación superior. No obstante, la actividad de coordinación entre personas que buscan aprender no es sencilla de gestionar. Esta complejidad aumenta cuando entre la actividad colaborativa surge un nuevo componente, la tecnología. ¿Qué se ha avanzado sobre el aprendizaje colaborativo mediado tecnológicamente? Este trabajo tiene como objetivo analizar el estado de la investigación sobre aprendizaje colaborativo en Educación Superior en los Entornos Virtuales de Aprendizaje (EVA). Para ello se realiza un análisis bibliométrico de las publicaciones indexadas de la base de datos SCOPUS…

Arc routing problems: A review of the past, present, and future

2020

[EN] Arc routing problems (ARPs) are defined and introduced. Following a brief history of developments in this area of research, different types of ARPs are described that are currently relevant for study. In addition, particular features of ARPs that are important from a theoretical or practical point of view are discussed. A section on applications describes some of the changes that have occurred from early applications of ARP models to the present day and points the way to emerging topics for study. A final section provides information on libraries and instance repositories for ARPs. The review concludes with some perspectives on future research developments and opportunities for emergin…

A Late Roman industrial complex with glass furnaces in the northern area of Valencia

2008

Abstract Information from excavations in Conde de Trenor street (1997) and Cisneros square (1986 and 1998) has confirmed that this area situated in the north of Valencia was a river port district dedicated to commercial activities and storing goods during the Roman Imperial period and maybe also in the Republican period. At the end of the third century A.D. the function of these port buildings changed and the evidence suggests that they became industrial workshops. The bases of three circular furnaces were found with fragments of glass containers, bottles, glasses, window panes and some slag. The recent excavation which took place in 2004–2006 in the Palau Cervero , 4 Cisneros square also s…

Modelling and Analysis of Nonstationary Vehicle-to-Infrastructure Channels with Time-Variant Angles of Arrival

2018

In mobile radio channel modelling, it is generally assumed that the angles of arrival (AOAs) are independent of time. This assumption does not in general agree with real-world channels in which the AOAs vary with the position of a moving receiver. In this paper, we first present a mathematical model for the time-variant AOAs. This model serves as the basis for the development of two nonstationary multipath fading channels models for vehicle-to-infrastructure communications. The statistical properties of both channel models are analysed with emphasis on the time-dependent autocorrelation function (ACF), time-dependent mean Doppler shift, time-dependent Doppler spread, and the Wigner-Ville sp…

Wireless Caching Aided 5G Networks

2018

Statistical modeling, simulation, and experimental verification of wideband indoor mobile radio channel

2018

This paper focuses on the modeling, simulation, and experimental verification of wideband single-input single-output (SISO) mobile fading channels for indoor propagation environments. The indoor reference channel model is derived from a geometrical rectangle scattering model, which consists of an infinite number of scatterers. It is assumed that the scatterers are exponentially distributed over the two-dimensional (2D) horizontal plane of a rectangular room. Analytical expressions are derived for the probability density function (PDF) of the angle of arrival (AOA), the PDF of the propagation path length, the power delay profile (PDP), and the frequency correlation function (FCF). An efficie…

An Effective Wireless Sensor Network Routing Protocol Based on Particle Swarm Optimization Algorithm

2022

Improving wireless communication and artificial intelligence technologies by using Internet of Things (Itoh) paradigm has been contributed in developing a wide range of different applications. However, the exponential growth of smart phones and Internet of Things (IoT) devices in wireless sensor networks (WSNs) is becoming an emerging challenge that adds some limitations on Quality of Service (QoS) requirements. End-to-end latency, energy consumption, and packet loss during transmission are the main QoS requirements that could be affected by increasing the number of IoT applications connected through WSNs. To address these limitations, an effective routing protocol needs to be designed for …

In the Direction of Service Guarantees for Virtualized Network Functions

2022

The trend of consolidating network functions from specialized hardware to software running on virtualization servers brings significant advantages for reducing costs and simplifying service deployment. However, virtualization techniques have significant limitations when it comes to networking as there is no support for guaranteeing that network functions meet their service requirements. In this paper, we present a design for providing service guarantees to virtualized network functions based on rate control. The design is a combination of rate regulation through token bucket filters and the regular scheduling mechanisms in operating systems. It has the attractive property that traffic profi…

Face Mask Detection Using Deep Convolutional Neural Network and MobileNetV2-Based Transfer Learning

2022

The rapid spreading of Coronavirus disease 2019 (COVID-19) is a major health risk that the whole world is facing for the last two years. One of the main causes of the fast spreading of this virus is the direct contact of people with each other. There are many precautionary measures to reduce the spread of this virus; however, the major one is wearing face masks in public places. Detection of face masks in public places is a real challenge that needs to be addressed to reduce the risk of spreading the virus. To address these challenges, an automated system for face mask detection using deep learning (DL) algorithms has been proposed to control the spreading of this infectious disease effecti…

A Deep Learning-Based Framework for Feature Extraction and Classification of Intrusion Detection in Networks

2022

An intrusion detection system, often known as an IDS, is extremely important for preventing attacks on a network, violating network policies, and gaining unauthorized access to a network. The effectiveness of IDS is highly dependent on data preprocessing techniques and classification models used to enhance accuracy and reduce model training and testing time. For the purpose of anomaly identification, researchers have developed several machine learning and deep learning-based algorithms; nonetheless, accurate anomaly detection with low test and train times remains a challenge. Using a hybrid feature selection approach and a deep neural network- (DNN-) based classifier, the authors of this re…