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An advanced GNSS code multipath detection and estimation algorithm / Negin Sokhandan in GPS solutions, vol 20 n° 4 (October 2016)
[article]
Titre : An advanced GNSS code multipath detection and estimation algorithm Type de document : Article/Communication Auteurs : Negin Sokhandan, Auteur ; James T. Curran, Auteur ; Ali Broumandan, Auteur ; Gérard Lachapelle, Auteur Année de publication : 2016 Article en page(s) : pp 627 - 640 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] code GNSS
[Termes IGN] méthode du maximum de vraisemblance (estimation)
[Termes IGN] milieu urbain
[Termes IGN] modèle de simulation
[Termes IGN] positionnement par GNSS
[Termes IGN] système de navigation
[Termes IGN] trajet multipleRésumé : (Auteur) A novel maximum likelihood-based range estimation algorithm is designed to provide robustness to multipath, which is recognized as a dominant error source in DS-CDMA-based navigation systems. The detection–estimation problem is jointly solved to sequentially estimate the parameters of each individual multipath component and predict the existence of a next possible component. A comparison between contemporary maximum likelihood-based multipath estimation techniques and this new technique is provided. A selection of realistic channel simulation models is used to assess relative performance under different operating situations. A set of real GPS L1/CA data processing results are also presented to further assess the applicability of the proposed algorithm for urban navigation. Numéro de notice : A2016--025 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s10291-015-0475-z En ligne : http://dx.doi.org/10.1007/s10291-015-0475-z Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83926
in GPS solutions > vol 20 n° 4 (October 2016) . - pp 627 - 640[article]Using a regional numerical weather prediction model for GNSS positioning over Brazil / Daniele Barroca Marra Alves in GPS solutions, vol 20 n° 4 (October 2016)
[article]
Titre : Using a regional numerical weather prediction model for GNSS positioning over Brazil Type de document : Article/Communication Auteurs : Daniele Barroca Marra Alves, Auteur ; Luiz Fernando Sapucci, Auteur ; Haroldo Antonio Marques, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 677 - 685 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] Amazonie
[Termes IGN] Brésil
[Termes IGN] modèle de simulation
[Termes IGN] modèle météorologique
[Termes IGN] positionnement ponctuel précis
[Termes IGN] propagation troposphérique
[Termes IGN] station GNSS
[Termes IGN] teneur en vapeur d'eau
[Termes IGN] troposphèreRésumé : (Auteur) The global navigation satellite system (GNSS) can provide centimeter positioning accuracy at low costs. However, in order to obtain the desired high accuracy, it is necessary to use high-quality atmospheric models. We focus on the troposphere, which is an important topic of research in Brazil where the tropospheric characteristics are unique, both spatially and temporally. There are dry regions, which lie mainly in the central part of the country. However, the most interesting area for the investigation of tropospheric models is the wet region which is located in the Amazon forest. This region substantially affects the variability of humidity over other regions of Brazil. It provides a large quantity of water vapor through the humidity convergence zone, especially for the southeast region. The interconnection and large fluxes of water vapor can generate serious deficiencies in tropospheric modeling. The CPTEC/INPE (Center for Weather Forecasting and Climate Studies/Brazilian Institute for Space Research) has been providing since July 2012 a numerical weather prediction (NWP) model for South America, known as Eta. It has yield excellent results in weather prediction but has not been used in GNSS positioning. This NWP model was evaluated in precise point positioning (PPP) and network-based positioning. Concerning PPP, the best positioning results were obtained for the station SAGA, located in Amazon region. Using the NWP model, the 3D RMS are less than 10 cm for all 24 h of data, whereas the values reach approximately 60 cm for the Hopfield model. For network-based positioning, the best results were obtained mainly when the tropospheric characteristics are critical, in which case an improvement of up to 7.2 % was obtained in 3D RMS using NWP models. Numéro de notice : A2016--028 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s10291-015-0477-x En ligne : http://dx.doi.org/10.1007/s10291-015-0477-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83930
in GPS solutions > vol 20 n° 4 (October 2016) . - pp 677 - 685[article]Propagating uncertainty through individual tree volume model predictions to large-area volume estimates / Ronald E. McRoberts in Annals of Forest Science, vol 73 n° 3 (September 2016)
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Titre : Propagating uncertainty through individual tree volume model predictions to large-area volume estimates Type de document : Article/Communication Auteurs : Ronald E. McRoberts, Auteur ; James A. Westfall, Auteur Année de publication : 2016 Article en page(s) : pp 625 – 633 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] diamètre des arbres
[Termes IGN] hauteur des arbres
[Termes IGN] incertitude des données
[Termes IGN] modèle de simulation
[Termes IGN] prédiction
[Termes IGN] propagation d'erreur
[Vedettes matières IGN] Inventaire forestierRésumé : (auteur) Key message : The effects on large-area volume estimates of uncertainty in individual tree volume model predictions were negligible when using simple random sampling estimators for large-area estimation, but non-negligible when using stratified estimators which reduced the effects of sampling variability.
Context : Forest inventory estimates of tree volume for large areas are typically calculated by adding model predictions of volumes for individual trees at the plot level and calculating the per unit area mean over plots. The uncertainty in the model predictions is generally ignored with the result that the precision of the large-area volume estimate is optimistic.
Aims : The primary objective was to estimate the effects on large-area volume estimates of volume model prediction uncertainty due to diameter and height measurement error, parameter uncertainty, and model residual variance.
Methods : Monte Carlo simulation approaches were used because of the complexities associated with multiple sources of uncertainty, the non-linear nature of the models, and heteroskedasticity.
Results : The effects of model prediction uncertainty on large-area volume estimates of growing stock volume were negligible when using simple random sampling estimators. However, with stratified estimators that reduce the effects of sampling variability, the effects of model prediction uncertainty were not necessarily negligible. The adverse effects of parameter uncertainty and residual variance were greater than the effects of diameter and height measurement errors.
Conclusion : The uncertainty of large-area volume estimates that do not account for model prediction uncertainty should be regarded with caution.Numéro de notice : A2016-711 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1007/s13595-015-0473-x Date de publication en ligne : 22/04/2015 En ligne : https://doi.org/10.1007/s13595-015-0473-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=82089
in Annals of Forest Science > vol 73 n° 3 (September 2016) . - pp 625 – 633[article]Diagnostic study of a high‐precipitation event in the Western Mediterranean: adequacy of current operational networks / Samiro Khodayar in Quarterly Journal of the Royal Meteorological Society, vol 142 n° S1 (August 2016)
[article]
Titre : Diagnostic study of a high‐precipitation event in the Western Mediterranean: adequacy of current operational networks Type de document : Article/Communication Auteurs : Samiro Khodayar, Auteur ; F. Raff, Auteur ; Norbert Kalthoff, Auteur ; Olivier Bock , Auteur Année de publication : 2016 Article en page(s) : pp 72 - 85 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] climat méditerranéen
[Termes IGN] données météorologiques
[Termes IGN] inondation
[Termes IGN] littoral méditerranéen
[Termes IGN] modèle de simulation
[Termes IGN] positionnement par GPS
[Termes IGN] précipitation
[Termes IGN] teneur en vapeur d'eauRésumé : (auteur) To investigate whether the spatial and temporal resolution of current operational observing systems in the Western Mediterranean (WMed) region suffice to adequately represent the atmospheric processes responsible for the initiation and intensification of convection, a diagnostic study of the HyMex Intensive Observation Period 8 (IOP8) is performed. During the IOP8, heavy rainfall with intense lightning and consequent devastating flash floods occurred in the WMed region. The synergy of operational networks in the northern WMed, including Global Positioning System (GPS) stations, rain gauges, weather stations, lightning sensors and radiosondes, was used to document in detail the evolution of the heavy precipitation event. In general, the resolution of the aforementioned networks adequately sampled the temporal and spatial variability of the atmospheric water vapour, as well as the position of mesoscale convergence zones which played a key role in the initiation and evolution of convective systems in this case. Nevertheless, high uncertainty was associated with the existence and location of moisture convergence zones and wind convergence lines over the sea, reflecting the need for model analysis and remote‐sensing observations to complete the documentation of the event. Numéro de notice : A2016--195 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1002/qj.2600 Date de publication en ligne : 11/06/2015 En ligne : https://doi.org/10.1002/qj.2600 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91857
in Quarterly Journal of the Royal Meteorological Society > vol 142 n° S1 (August 2016) . - pp 72 - 85[article]A multi-instrument and multi-model assessment of atmospheric moisture variability over the Western Mediterranean during HyMeX / Patrick Chazette in Quarterly Journal of the Royal Meteorological Society, vol 142 n° S1 (August 2016)
[article]
Titre : A multi-instrument and multi-model assessment of atmospheric moisture variability over the Western Mediterranean during HyMeX Type de document : Article/Communication Auteurs : Patrick Chazette, Auteur ; Cyrille Flamant, Auteur ; Xiaoxia Shang, Auteur ; Julien Totems, Auteur ; Jean-Christophe Raut, Auteur ; Alexis Doerenbecher, Auteur ; Véronique Ducrocq, Auteur ; Nadia Fourrié, Auteur ; Olivier Bock , Auteur ; Sophie Cloché, Auteur Année de publication : 2016 Article en page(s) : pp 7 - 22 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] données météorologiques
[Termes IGN] lidar Raman
[Termes IGN] littoral méditerranéen
[Termes IGN] modèle de simulation
[Termes IGN] modèle météorologique
[Termes IGN] positionnement par GPS
[Termes IGN] prévision météorologique
[Termes IGN] récepteur GPS
[Termes IGN] teneur en vapeur d'eauMots-clés libres : water vapour lidars Numerical Weather Prediction Models Weather Research and Forecasting model Mediterranean HyMeX cross-validation Résumé : (auteur) The Hydrological cycle in the Mediterranean eXperiment (HyMeX) was held in autumn 2012 during which part of the observational effort was established on Menorca Island to characterize the upwind marine low-level flow. The ground-based Water-vapour Raman Lidar (WALI), the airborne water-vapour lidar LEANDRE 2 and boundary-layer pressurized balloons were implemented during the first Special Observing Period and contributed to characterize water vapour variability in the vicinity of the Balearic Islands, together with the existing network of Global Positioning System receivers. Furthermore, analyses from regional and global numerical weather prediction (NWP) models (AROME-WMED, the ECMWF/IFS NWP system and the Weather Research and Forecasting (WRF) model) were also available over large domains encompassing part of or the entire western Mediterranean basin. We assess the consistency of water vapour mixing ratio (WVMR) profiles and integrated water vapour contents (IWVC) derived from the different datasets by comparing them to a common reference, the ground-based lidar WALI. We use consistency indicators such as root-mean-square errors, biases and correlations. Comparison between WVMR profiles from ground-based and airborne lidars (ground-based lidar and boundary-layer pressurized balloons) leads to a root-mean-square error lower than 1.6 g kg−1 (1.3 g kg−1) when the closest possible air masses are sampled. We observed a good agreement between the vertical WVMR profiles derived from WALI and the numerical models with correlations higher than 0.7 and root-mean-square errors lower than 2 g kg−1. Regarding IWVCs, the models exhibit biases less than 2 kg m−2, root-mean-square errors lower than 2.3 g kg−1 and correlations higher than 0.86 when compared to WALI. Finally, AROME-WMED 48 h forecasts were compared with WALI data composited over eleven 48 h periods. The quality of the forecast does not visibly degrade within the 48 h period from the initial analyses. Numéro de notice : A2016-936 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1002/qj.2671 Date de publication en ligne : 18/09/2015 En ligne : http://dx.doi.org/10.1002/qj.2671 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83164
in Quarterly Journal of the Royal Meteorological Society > vol 142 n° S1 (August 2016) . - pp 7 - 22[article]Measurement of surface changes in a scaled-down landslide model using high-speed stereo image sequences / Tiantian Feng in Photogrammetric Engineering & Remote Sensing, PERS, vol 82 n° 7 (juillet 2016)PermalinkNationwide airborne laser scanning based models for volume, biomass and dominant height in Finland / Eetu Kotivuori in Silva fennica, vol 50 n° 4 (2016)PermalinkBelastungen der deutschen Forstwirtschaft aus der Schutz- und Erholungsfunktion des Waldes / Markus Dög in Landbauforschung, vol 66 n° 2 (06-2016)PermalinkDeveloping a dynamic growth model for maritime pine in Asturias (NW Spain): comparison with nearby regions / Manuel Arias-Rodil in Annals of Forest Science, vol 73 n° 2 (June 2016)PermalinkAn effective toolkit for the interpolation and gross error detection of GPS time series / X. Wang in Survey review, vol 48 n° 348 (May 2016)PermalinkLes données géographiques 3D pour simuler l'impact de la réglementation urbaine sur la morphologie du bâti / Mickaël Brasebin in Cartes & Géomatique, n° 227 (mars - mai 2016)PermalinkSLEUTH* : un modèle d’expansion urbaine scénario-dépendant / Omar Doukari in Revue internationale de géomatique, vol 26 n° 1 (janvier - mars 2016)PermalinkA domain specific language for spatial simulation scenarios / Luís Moreira de Sousa in Geoinformatica, vol 20 n° 1 (January - March 2016)PermalinkPermalinkMéthode pour la reconstruction, l'analyse et l'exploitation de réseaux tridimensionnels en milieu urbain / Marie Lacroix (2016)Permalink