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Automatic cloud resource management for interactive remote geovisualization / Tong Zhang in Transactions in GIS, vol 22 n° 6 (December 2018)  

Public [article]  inTransactions in GIS > vol 22 n° 6 (December 2018) . - pp 1437 - 1461 Titre : Automatic cloud resource management for interactive remote geovisualization Type de document : Article/Communication Auteurs : Tong Zhang, Auteur ; Jing Li, Auteur Année de publication : 2018 Article en page(s) : pp 1437 - 1461 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] automatisation [Termes IGN] informatique en nuage [Termes IGN] modèle dynamique [Vedettes matières IGN] Géovisualisation Résumé : (Auteur) Remote geovisualization has gained momentum to support large‐scale geospatial data analysis and complex decision‐making over the last few years. Cloud computing, due to its capabilities to deliver on‐demand computing resources, has been embraced to develop and deploy interactive and scalable remote geovisualization applications. However, current cloud computing frameworks do not offer a versatile resource management scheme that is readily applicable for online remote visualization services, which usually require maintaining a satisfactory service level over time under dynamic workloads. To address this gap, we propose an automatic cloud resource management approach based on a bi‐level scheduling and horizontal scaling scheme to exploit cloud resources efficiently. At the lower level, a dynamic task‐scheduling scheme using collaborative filtering techniques is proposed to allocate virtual cloud resources to execute sub‐tasks. The scheduling scheme considers spatio‐temporal patterns presented in visualization views. At the upper level, reinforcement learning is adopted to perform resource auto‐scaling based on a reward function that integrates three different facets, namely: time cost, resource cost, and service stability. The original reinforcement learning algorithm is improved in two main aspects: (1) considering the delay of resource provisioning that is common in cloud environments; and (2) using online Gaussian estimation to estimate Q values. Task scheduling and auto‐scaling interact with each other and are integrated to deliver a comprehensive and responsive resource management solution. Experimental results demonstrate that our approach outperforms several existing cloud resource management methods. The proposed approach is also applicable for other interactive visualization applications, which have similar workload characteristics and performance requirements as interactive remote geovisualization. Numéro de notice : A2018-567 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/tgis.12479 Date de publication en ligne : 10/12/2018 En ligne : https://doi.org/10.1111/tgis.12479 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92286 [article]

The use of geometric indicators to estimate the quantitative completeness of street blocks in OpenStreetMap / Qi Zhou in Transactions in GIS, vol 22 n° 6 (December 2018)  

Public [article]  inTransactions in GIS > vol 22 n° 6 (December 2018) . - pp 1550 - 1572 Titre : The use of geometric indicators to estimate the quantitative completeness of street blocks in OpenStreetMap Type de document : Article/Communication Auteurs : Qi Zhou, Auteur ; YuanJian Tian, Auteur Année de publication : 2018 Article en page(s) : pp 1550 - 1572 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées [Termes IGN] données localisées des bénévoles [Termes IGN] exhaustivité des données [Termes IGN] îlot urbain [Termes IGN] indicateur spatial [Termes IGN] OpenStreetMap [Termes IGN] qualité des données Résumé : (Auteur) OpenStreetMap (OSM) is a free global map dataset that was created by volunteers around the world. This inevitably means that there are a number of quality issues with the final OSM product, however. Extensive research has therefore been carried out to assess the quality of this product by applying a range of measures versus reference datasets, but little effort to date has been focused on quantitative quality estimation without reference datasets. The aim of this study is therefore to quantitatively estimate the completeness of street blocks in an OSM dataset. This was accomplished by initially exploring the relationship between geometric indicators (i.e., area, perimeter, and density) and street block completeness in an OSM road dataset, before these relationships were applied to quantitatively estimate completeness in other datasets. The results of this study show that: (1) street block completeness is positively correlated with density and negatively correlated with area and perimeter; and (2) in most cases, estimated completeness values for all street blocks within an OSM road dataset do not differ by more than 10% in absolute terms from actual completeness values. These results indicate that geometric indicators can be used as proxies to quantitatively estimate road completeness in OSM datasets. Numéro de notice : A2018-568 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/tgis.12486 Date de publication en ligne : 10/12/2018 En ligne : https://doi.org/10.1111/tgis.12486 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92287 [article]