Centre de documentation
scientifique

Framework for automatic coral reef extraction using Sentinel-2 image time series / Qizhi Zhang in Marine geodesy, vol 45 n° 3 (May 2022)  

Public [article]  inMarine geodesy > vol 45 n° 3 (May 2022) . - pp 195 - 231 Titre : Framework for automatic coral reef extraction using Sentinel-2 image time series Type de document : Article/Communication Auteurs : Qizhi Zhang, Auteur ; Jian Zhang, Auteur ; Liang Cheng, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : pp 195 - 231 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique [Termes IGN] Chine [Termes IGN] extraction de traits caractéristiques [Termes IGN] filtrage de points [Termes IGN] filtrage spatiotemporel [Termes IGN] image Sentinel-MSI [Termes IGN] mesure de similitude [Termes IGN] nébulosité [Termes IGN] récif corallien [Termes IGN] série temporelle Résumé : (auteur) Using supervised and unsupervised classification on a single image to extract coral reef extent results in missing data and wrong extraction results. To improve the accuracy of coral reef extraction, this study proposes a novel technical framework for automatic coral reef extraction based on an image filtering strategy and spatiotemporal similarity measurements of pixel-level Sentinel-2 image time series. This method was applied to the Anda Reef, Daxian Reef, and Nanhua Reef, China, using 1464 Sentinel-2 images obtained from 2015–2020. Sentinel-2 images were automatically selected considering space, time, cloud cover, and image entropy after atmospheric correction. With the binary classification measurement standard using the digitization coral reef results of the Sentinel-2 images as the true value, the time series established by the modified normalized difference water index demonstrated high robustness and accuracy. Analyzing the time series curves of the coral reef and deep water verified that the spatiotemporal similarity measurement of this framework can stably extract the boundaries of the coral reef. Numéro de notice : A2022-353 Affiliation des auteurs : non IGN Thématique : IMAGERIE/INFORMATIQUE Nature : Article DOI : 10.1080/01490419.2022.2051648 Date de publication en ligne : 28/03/2022 En ligne : https://doi.org/10.1080/01490419.2022.2051648 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100550 [article]

Forest gaps retard carbon and nutrient release from twig litter in alpine forest ecosystems / Bo Tan in European Journal of Forest Research, vol 139 n° 1 (February 2020)  

Public [article]  inEuropean Journal of Forest Research > vol 139 n° 1 (February 2020) Titre : Forest gaps retard carbon and nutrient release from twig litter in alpine forest ecosystems Type de document : Article/Communication Auteurs : Bo Tan, Auteur ; Jian Zhang, Auteur ; Wanqin Yang, Auteur ; et al., Auteur Année de publication : 2020 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] azote [Termes IGN] carbone [Termes IGN] Chine [Termes IGN] dégel [Termes IGN] écosystème forestier [Termes IGN] forêt alpestre [Termes IGN] gelée [Termes IGN] hiver [Termes IGN] litière [Termes IGN] nutriment végétal [Termes IGN] phosphore [Termes IGN] température au sol [Vedettes matières IGN] Botanique Résumé : (auteur) Changes in soil microclimate driven by forest gaps have accelerated mass loss and carbon (C), nitrogen (N) and phosphorus (P) release from foliar litter in alpine forests ecosystems. Yet, it is unclear whether the same gap effect occurs in twig litter decomposition. A 4-year decomposition experiment was conducted in an alpine forest to explore the litter mass loss and C, N and P release among four gap treatments, including (1) closed canopy, (2) small gap ( Numéro de notice : A2020-229 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1007/s10342-019-01229-8 Date de publication en ligne : 12/09/2019 En ligne : https://doi.org/10.1007/s10342-019-01229-8 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94966 [article]

Deep learning based vehicular mobility models for intelligent transportation systems / Jian Zhang (2018)  

Public Titre : Deep learning based vehicular mobility models for intelligent transportation systems Type de document : Thèse/HDR Auteurs : Jian Zhang, Auteur ; Abdelkader El Kamel, Directeur de thèse Editeur : Lille [France] : Ecole Centrale de Lille Année de publication : 2018 Importance : 175 p. Format : 21 x 30 cm Note générale : bibliographie Thèse présentée en vue d’obtenir le grade de Docteur, Spécialité : Automatique, génie informatique, traitement du signal et des images, Doctorat délivré par Centrale Lille Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Intelligence artificielle [Termes IGN] analyse spatiale [Termes IGN] apprentissage profond [Termes IGN] chaîne de Markov [Termes IGN] classification par réseau neuronal [Termes IGN] données de flux [Termes IGN] itération [Termes IGN] mobilité humaine [Termes IGN] modèle de simulation [Termes IGN] sécurité routière [Termes IGN] système de transport intelligent [Termes IGN] trafic routier [Termes IGN] transport [Termes IGN] UML [Termes IGN] véhicule sans pilote Index. décimale : THESE Thèses et HDR Résumé : (auteur) The intelligent transportation systems gain great research interests in recent years. Although the realistic traffic simulation plays an important role, it has not received enough attention. This thesis is devoted to studying the traffic simulation in microscopic level, and proposes corresponding vehicular mobility models. Using deep learning methods, these mobility models have been proven with a promising credibility to represent the vehicles in real-world. Firstly, a data-driven neural network based mobility model is proposed. This model comes from real-world trajectory data and allows mimicking local vehicle behaviors. By analyzing the performance of this basic learning based mobility model, we indicate that an improvement is possible and we propose its specification. An HMM is then introduced. The preparation of this integration is necessary, which includes an examination of traditional dynamics based mobility models and the adaptation method of “classical” models to our situation. At last, the enhanced model is presented, and a sophisticated scenario simulation is built with it to validate the theoretical results. The performance of our mobility model is promising and implementation issues have also been discussed. Note de contenu : 1- Introduction 2- Neural network based data-driven mobility model 3- Enhanced Mobility Model with HMM 4- Experiment platform and scenario simulation Conclusions and Perspectives Numéro de notice : 25873 Affiliation des auteurs : non IGN Thématique : INFORMATIQUE/MATHEMATIQUE Nature : Thèse française Note de thèse : Thèse de Doctorat : Automatique, génie informatique, traitement du signal et des images : École Centrale Lille : 2018 Organisme de stage : CRIStAL (laboratoire) nature-HAL : Thèse DOI : sans En ligne : https://tel.archives-ouvertes.fr/tel-02136219/document Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95562

A hybrid system of expanding 2D GIS into 3D space / L. Yu in Cartography and Geographic Information Science, vol 39 n° 3 (July 2012)  

Public [article]  inCartography and Geographic Information Science > vol 39 n° 3 (July 2012) . - pp 140 - 153 Titre : A hybrid system of expanding 2D GIS into 3D space Type de document : Article/Communication Auteurs : L. Yu, Auteur ; D. Sun, Auteur ; Z. Peng, Auteur ; Jian Zhang, Auteur Année de publication : 2012 Article en page(s) : pp 140 - 153 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes d'information géographique [Termes IGN] analyse spatiale [Termes IGN] SIG 2D [Termes IGN] système d'information géographique [Termes IGN] visualisation 3D Résumé : (Auteur) A hybrid system that integrates two-dimensional (2D) GIS and three-dimensional (3D) visualization has been developed to provide unique solutions to application domains where traditional 2D GIS and 3D visualization cannot alone provide a solution. In this paper, we focus on three key issues in realizing such an integrated system, including large-scale terrain rendering, 2D and 3D combination display (for example, rendering 2D GIS layers in 3D space), expanding traditional 2D GIS analysis functions into a 3D environment, and visualizing 3D geographical data. A generic framework is developed to integrate 3D visualization with various types of 2D GIS, such as commercial GIS software, open source GIS software and spatial databases. A prototype 2D and 3D hybrid system that seamlessly integrates 2D GIS (developed with ArcEngine) and 3D rendering engine (developed with DirectX) is then developed based on the framework. In this hybrid system, 2D and 3D data are viewed within the same scene. Multiple 2D GIS layers are overlaid on the base terrain using a Level of Detail (LOD) model. Advanced query functions, data accessing, data management and spatial analysis, which are executed in the traditional 2D GIS, are provided to users in a 3D environment by continuously transforming information between the 2D GIS subsystem and the 3D subsystem. The 3D data are organized and displayed by Keyhole Markup Language (KML) and textured 3D models in the COLLAborative Design Activity (COLLADA)*format. The prototype demonstrates that this hybrid system has effectively addressed the three key issues identified above and that it can seamlessly integrate 2D GIS and 3D visualization. The hybrid system has great potential to be employed in many application domains, such as urban planning, landscape design and environmental decision making, among others, to enhance the 3D design capability and facilitate public participation in the planning, design and decision-making process. Numéro de notice : A2012-491 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Article DOI : 10.1559/15230406393140 En ligne : https://doi.org/10.1559/15230406393140 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31937 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
032-2012031	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Density dependence on tree survival in an old-growth temperate forest in northeastern China / Jian Zhang in Annals of Forest Science, Vol 66 n° 2 (march 2009)  

Public [article]  inAnnals of Forest Science > Vol 66 n° 2 (march 2009) . - n° 204 Titre : Density dependence on tree survival in an old-growth temperate forest in northeastern China Titre original : La survie des arbres dépend de la densité dans une ancienne forêt tempérée du nord-est de la Chine Type de document : Article/Communication Auteurs : Jian Zhang, Auteur ; Zhanqing Hao, Auteur ; I.-Fang Sun, Auteur ; Bo Song, Auteur ; Ji Ye, Auteur ; Buhang Li, Auteur ; Xugao Wang, Auteur Année de publication : 2009 Article en page(s) : n° 204 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Végétation [Termes IGN] Chine [Termes IGN] densité de la végétation [Termes IGN] dépérissement [Termes IGN] étage de végétation [Termes IGN] forêt tempérée [Termes IGN] mortalité [Termes IGN] structure spatiale Résumé : (auteur) Density dependence is a major mechanism for shaping plant communities. However, its role in regulating diverse, mixed natural tree communities is less certain. In this study we investigated density-dependent effects in a large-scale (25 ha) old-growth temperate forest in northeastern China. Spatial patterns of neighborhood distribution in the plot were analyzed using various methods for inferring competition, including (1) pair correlation function to determine spatial patterns of pre-mortality and post-mortality and (2) neighborhood analysis of individuals to examine the extent to which tree survival is correlated with other covariates. Results showed that, for common species, 3 of 5 canopy species and 3 of 8 midstory and understory species were random in mortality. Negative density-dependent mortality was not found when trees reach 1 cm in DBH. There was no significant correlation for canopy species between tree survival and conspecific abundance, but largely positive correlations for midstory and understory species. In contrast, tree survival was found to negatively correlate with conspecific basal area for most species, indicating strong intraspecific competition. No strong interspecific density dependence was found in the forest. Numéro de notice : A2009-715 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1051/forest/2008086 Date de publication en ligne : 28/02/2009 En ligne : https://www.afs-journal.org/articles/forest/abs/2009/02/f08149/f08149.html Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=71944 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
IFN-001-P000317	PER	Revue	Nogent-sur-Vernisson	Salle périodiques	Exclu du prêt