Search results for "Application"
showing 10 items of 5559 documents
Four-Level Three-Phase Inverter With Reduced Component Count for Low and Medium Voltage Applications
2021
This paper proposes a novel three-phase topology with a reduced component count for low- and medium-voltage systems. It requires three bidirectional switches and twelve unidirectional switches for producing four-level voltages without using flying capacitors or clamping diodes, reducing the size, cost, and losses. Removing flying capacitors and clamping diodes allows it to simplify control algorithms and increase the reliability, efficiency, and lifetime. A modified low-frequency modulation (LFM) scheme is developed and implemented on the proposed topology to produce a staircase voltage with four steps. Further, a level-shifted pulse width modulation (LSPWM) is used to reduce the filter siz…
Expectations for supporting student engagement with learning analytics : an academic path perspective
2021
There has been a growing interest in higher education to explore how learning analytics (LA) could be used to support student engagement. Providing actionable feedback with LA for students is an emerging area of research. Previous studies have commonly focused on course-level aspects of supporting engagement with LA, but students' perspectives have received limited attention. This study analyzed pre-service teachers’ needs and expectations for LA to support student engagement on the academic path level, which means observing the continuum of study periods and academic years. Qualitative content analysis was conducted for video-recorded student small-group conversations to analyze in-depth h…
Relative risk estimation of dengue disease at small spatial scale
2017
Abstract Background Dengue is a high incidence arboviral disease in tropical countries around the world. Colombia is an endemic country due to the favourable environmental conditions for vector survival and spread. Dengue surveillance in Colombia is based in passive notification of cases, supporting monitoring, prediction, risk factor identification and intervention measures. Even though the surveillance network works adequately, disease mapping techniques currently developed and employed for many health problems are not widely applied. We select the Colombian city of Bucaramanga to apply Bayesian areal disease mapping models, testing the challenges and difficulties of the approach. Methods…
Exploring social media network landscape of post-Soviet space
2019
The “post-Soviet space” consists of countries with a substantial fraction of the world’s population; however, unlike many other regions, its social media network landscape is still somewhat under-explored. This paper aims at filling this gap. To this purpose, we use anonymized data on user friendships at VK.com (also known as VKontakte and, informally, as “Russian Facebook”), which is the largest and most popular social media portal in the post-Soviet space with hundreds of millions of user accounts. Using the VK network snapshots from October 2015 to December 2016, we conduct a “multiscale” empirical study of this network by considering conn…
A Realistic Model to Support Rescue Operations After an Earthquake via UAVs
2022
In this paper, we consider the problem of completely flying over an area just hit by an earthquake with a fleet of Unmanned Aerial Vehicles (UAVs) to opportunely direct rescue teams. The cooperation between UAVs ensures that the search for possible survivors can be faster and more effective than the solutions currently implemented by civil protection. To study this scenario, we introduce the Cover by Multitrips with Priorities (CMP) problem, which tries to keep into account all the main real-life issues connected to the flight and coordination of the UAVs. We conduct a theoretical study to estimate the best number of UAVs and additional batteries, to give indications to the organization tha…
Implementation of a web and mobile solution for vehicular management based on Aspects Architecture and Agile Methodologies: An educational approach f…
2017
espanolEn el presente articulo se detallan el analisis, aplicacion de metodologias agiles, y tecnologias de codigo abierto en el desarrollo de una aplicacion web y movil, para automatizar y controlar el parque automotor de la Universidad Tecnica Particular de Loja (UTPL), dicha aplicacion fue desarrollada por los profesionales en formacion del componente educativo Programacion Web en marco del proyecto Computacion Afectiva. Dentro de las funciones esenciales del aplicativo esta la gestion de vehiculos que implica el registro: ordenes de combustible y mantenimiento, facturas, proveedores, conductores y vehiculos; ademas de la gestion de prestamos de vehiculos que implica el registro de solic…
Joint Resource Allocation and UAV Scheduling With Ground Radio Station Sleeping
2021
Applications of Unmanned aerial vehicles (UAVs) have advanced rapidly in recent years. The UAVs are used for a variety of applications, including surveillance, disaster management, precision agriculture, weather forecasting, etc. In near future, the growing number of UAV applications would necessitate densification of UAV infrastructure (ground radio station (GRS) and ground control station (GCS)) at the expense of increased energy consumption for UAV communications. Maximizing the energy efficiency of this UAV infrastructure is important. Motivated by this, we propose joint resource allocation and UAV scheduling with GRS sleeping (GRSS). Further, we propose the use of coordinated multi-poi…
Precision Oliviculture: Research Topics, Challenges, and Opportunities—A Review
2022
Since the beginning of the 21st century, there has been an increase in the agricultural area devoted to olive growing and in the consumption of extra virgin olive oil (EVOO). The continuous change in cultivation techniques implemented poses new challenges to ensure environmental and economic sustainability. In this context, precision oliviculture (PO) is having an increasing scientific interest and impact on the sector. Its implementation depends on various technological developments: sensors for local and remote crop monitoring, global navigation satellite system (GNSS), equipment and machinery to perform site-specific management through variable rate application (VRA), implementation of g…
Los Mapas de Gestión de las Empresas Cotizadas Chilenas. Análisis Cuantitativo
2017
espanolEste articulo evalua las clases de gestion adoptadas por las empresas localizadas en la region de Las Condes (Chile) a traves de la metodologia contable de los graficos radiales. Esta metodologia aplicada sobre dos empresas que utilizan dos diferentes clases de gestion, justifica las relaciones que existen entre los indicadores radiales y financieros. Los resultados contrastados con los precios de las acciones de las empresas analizadas en el mercado secundario confirman la validez de las relaciones anteriores. El analisis realizado ha permitido obtener generalizaciones sobre las distintas clases de gestion en la comuna de Las Condes, de acuerdo con el sentido multidimensional de los…
Can aromaticity be connected with molecular polarizability? A theoretical study of benzene isomers and five-membered heterocyclic molecules
2004
Extended calculations of molecular electric dipole polarizability tensor, at Hartree-Fock and correlated level of accuracy (MP2, CCS, CC2, CCSD, and CCSD(T)) have been carried out to investigate whether aromaticity could be related to the electric dipole polarizability of planar ring systems. The calculations prove the exaltation of the average property of conjugated molecules, which is possibly due to their easily polarizable π-electron cloud. On the other hand, theoretical out-of-plane polarizability components are smaller in benzene than in any other C$_6$H$_6$ isomer. The aromatic stabilization energies of monosubstituted five-membered conjugated cyclic molecules increase in the same di…