Search results for "Networks"
showing 10 items of 3260 documents
Inventer et errer au XVIIIe siècle
2014
os nat; National audience; no abstract
Performances of neural networks for deriving LAI estimates from existing CYCLOPES and MODIS products
2008
International audience; This paper evaluates the performances of a neural network approach to estimate LAI from CYCLOPES and MODIS nadir normalized reflectance and LAI products. A data base was generated from these products over the BELMANIP sites during the 2001-2003 period. Data were aggregated at 3 km x 3 km, resampled at 1/16 days temporal frequency and filtered to reject outliers. VEGETATION and MODIS reflectances show very consistent values in the red, near infrared and short wave infrared bands. Neural networks were trained over part of this data base for each of the 6 MODIS biome classes to retrieve both MODIS and CYCLOPES LAI products. Results show very good performances of neural …
Joint Optimization of Sensor Selection and Routing for Distributed Estimation in Wireless Sensor Networks
2014
Avances recientes en redes inalámbricos de sensores (WSNs, Wireless Sensor Networks) han posibilitado que pequeños sensores, baratos y con recursos limitados tanto en sensado, comunicación, como en computación, sean desplegados a gran escala. En consecuencia, las WSNs pueden ofrecer diversos servicios en importantes aplicaciones para la sociedad. Entre las varias restricciones que aparecen en el diseño de WSNs, tales como la limitación en energía disponible, procesamiento y memoria, la limitación en energía es muy importante ya que en muchas aplicaciones (ej., monitorización remota de diferentes entornos, edificios administrativos, monitoreo del hábitat, los incendios forestales, la atenció…
Semantically-enhanced advertisement recommender systems in social networks
2017
El objetivo principal de la investigación es estudiar y diseñar un entorno de recomendación publicitaria en las redes sociales que puede ser enriquecido mediante tecnologías semánticas. A pesar de que existen muchas aplicaciones y soluciones para los sistemas de recomendación, en este estudio se diseña un framework robusto con un rendimiento adecuado para poder ser implementado en las redes sociales con el objetivo de ampliar los propósitos de negocio. De este objetivo principal se pueden derivar los siguientes objetivos secundarios: 1. Superar las limitaciones iniciales de los métodos clásicos de recomendación. 2. Aumentar la calidad y precisión de las recomendaciones y el rendimiento del …
Hyvää verkko-opetusta etsimässä: oppimista edistävät ja estävät tekijät verkko-oppimisympäristöissä – opiskelijoiden kokemuksen ja opettajien arviot
2003
Tutkimuksen tarkoituksena oli selvittää opiskelijoiden ja opettajien käsityksiä hyvästä verkko-opetuksesta ja -opiskelusta. Tutkimuksessa keskityttiin erityisesti verkko- opettajan roolin ja tehtävien tarkasteluun. Verkko-opetusta tutkittiin osana opetus-opiskelu-oppiminen prosessia (Uljens 1997, Kansanen 1999). Hyvän verkko-opettajan ominaisuuksia etsittiin tehokkaan opettajan kriteerien (Tirri 1993), opettajan pedagogisen ajattelun ja verkko-opettajatutkimuksien lähtökohdista käsin. Mielekäs oppiminen määriteltiin Jonassenin (1995) esittämien kriteerien lähtökohdista. Tutkimuksen empiirinen aineisto koostui vuosina 1995-1999 Helsingin yliopiston virtuaalisen avoimen yliopiston (HEVI) ja A…
Statistical Regularities in ATM: network properties, trajectory deviations and delays
2012
One of the key enabler to the productivity and efficiency shift foreseen by SESAR will be the business-trajectory concept. The path to a deep understanding of how this new concept impacts on the future SESAR Air Traffic Management scenario goes through a better understanding of the actual air traffic network, and this will be done in the present paper by analyzing traffic data within the framework of complex network analysis. In this paper we will consider flights trajectory data from the Data Demand Repository database. In a first investigation, we perform a network study of the air traffic infrastructure starting from the airports and then refining our analysis at the level of navigation …
ELSA Project: Toward a complex network approach to ATM delays analysis
2011
The paper presents the preliminary results delivered by the WPE project ELSA. After some introductory notes about the project aims and structure, the paper shows how tools borrowed by the Complex Network Theory can be used to study the issue of delays in the air traffic system.
Analysis of the Structure and Dynamics of European Flight Networks
2022
We analyze structure and dynamics of flight networks of 50 airlines active in the European airspace in 2017. Our analysis shows that the concentration of the degree of nodes of different flight networks of airlines is markedly heterogeneous among airlines reflecting heterogeneity of the airline business models. We obtain an unsupervised classification of airlines by performing a hierarchical clustering that uses a correlation coefficient computed between the average occurrence profiles of 4-motifs of airline networks as similarity measure. The hierarchical tree is highly informative with respect to properties of the different airlines (for example, the number of main hubs, airline participa…
Pharmacogenomic identification of small molecules for lineage specific manipulation of subventricular zone germinal activity
2017
Strategies for promoting neural regeneration are hindered by the difficulty of manipulating desired neural fates in the brain without complex genetic methods. The subventricular zone (SVZ) is the largest germinal zone of the forebrain and is responsible for the lifelong generation of interneuron subtypes and oligodendrocytes. Here, we have performed a bioinformatics analysis of the transcriptome of dorsal and lateral SVZ in early postnatal mice, including neural stem cells (NSCs) and their immediate progenies, which generate distinct neural lineages. We identified multiple signaling pathways that trigger distinct downstream transcriptional networks to regulate the diversity of neural cells …
Technostress and social networking services: Explaining users' concentration, sleep, identity, and social relation problems
2018
It is common for users of social networking sites and services (SNS) to suffer from technostress and the various associated strains that hinder their well‐being. Despite prior SNS stress studies having provided valuable knowledge regarding SNS stressors and their use consequences, they have not examined the various strains related to well‐being that those stressors can create nor the underlying SNS characteristics. To address this gap in the research, we used a qualitative approach involving narrative interviews. As a contribution, our findings reveal four types of strains related to well‐being (concentration problems, sleep problems, identity problems, and social relation problems) as well…