Descripteur
Termes IGN > mathématiques > statistique mathématique > analyse de variance
analyse de variance
Commentaire :
Statistique,
Statistique mathématique. >> Analyse de covariance, Échantillonnage (statistique), Plan d'expérience. >>Terme(s) spécifique(s) : Analyse multivariée, Degré de liberté (physique), Écart type, Surface de réponse (statistique). Equiv. LCSH : Analysis of variance. Domaine(s) : 510. Voir aussi |
Documents disponibles dans cette catégorie (240)
Ajouter le résultat dans votre panier
Visionner les documents numériques
Affiner la recherche Interroger des sources externes
Etendre la recherche sur niveau(x) vers le bas
Validation of GOCE gravity field models by means of orbit residuals and geoid comparisons / Thomas Gruber in Journal of geodesy, vol 85 n° 11 (November /2011)
[article]
Titre : Validation of GOCE gravity field models by means of orbit residuals and geoid comparisons Type de document : Article/Communication Auteurs : Thomas Gruber, Auteur ; P. Visser, Auteur ; C. Ackermann, Auteur ; M. Hosse, Auteur Année de publication : 2011 Article en page(s) : pp 845 - 860 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] analyse comparative
[Termes IGN] analyse de variance
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] données GOCE
[Termes IGN] données GRACE
[Termes IGN] géoïde gravimétrique
[Termes IGN] géoïde terrestre
[Termes IGN] harmonique sphérique
[Termes IGN] limite de résolution géométrique
[Termes IGN] orbitographie
[Termes IGN] résiduRésumé : (Auteur) Three GOCE-based gravity field solutions have been computed by ESA’s high-level processing facility and were released to the user community. All models are accompanied by variance-covariance information resulting either from the least squares procedure or a Monte-Carlo approach. In order to obtain independent external quality parameters and to assess the current performance of these models, a set of independent tests based on satellite orbit determination and geoid comparisons is applied. Both test methods can be regarded as complementary because they either investigate the performance in the long wavelength spectral domain (orbit determination) or in the spatial domain (geoid comparisons). The test procedure was applied to the three GOCE gravity field solutions and to a number of selected pre-launch models for comparison. Orbit determination results suggest, that a pure GOCE gravity field model does not outperform the multi-year GRACE gravity field solutions. This was expected as GOCE is designed to improve the determination of the medium to high frequencies of the Earth gravity field (in the range of degree and order 50 to 200). Nevertheless, in case of an optimal combination of GOCE and GRACE data, orbit determination results should not deteriorate. So this validation procedure can also be used for testing the optimality of the approach adopted for producing combined GOCE and GRACE models. Results from geoid comparisons indicate that with the 2 months of GOCE data a significant improvement in the determination of the spherical harmonic spectrum of the global gravity field between degree 50 and 200 can be reached. Even though the ultimate mission goal has not yet been reached, especially due to the limited time span of used GOCE data (only 2 months), it was found that existing satellite-only gravity field models, which are based on 7 years of GRACE data, can already be enhanced in terms of spatial resolution. It is expected that with the accumulation of more GOCE data the gravity field model resolution and quality can be further enhanced, and the GOCE mission goal of 1–2 cm geoid accuracy with 100 km spatial resolution can be achieved. Numéro de notice : A2011-470 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-011-0486-7 Date de publication en ligne : 08/06/2011 En ligne : https://doi.org/10.1007/s00190-011-0486-7 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31364
in Journal of geodesy > vol 85 n° 11 (November /2011) . - pp 845 - 860[article]Réservation
Réserver ce documentExemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 266-2011111 RAB Revue Centre de documentation En réserve L003 Disponible Potentialities of multifrequency ionospheric correction in Global Navigation Satellite Systems / B. Kim in Journal of geodesy, vol 85 n° 3 (March 2011)
[article]
Titre : Potentialities of multifrequency ionospheric correction in Global Navigation Satellite Systems Type de document : Article/Communication Auteurs : B. Kim, Auteur ; M. Tinin, Auteur Année de publication : 2011 Article en page(s) : pp 159 - 169 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] correction ionosphérique
[Termes IGN] diffraction
[Termes IGN] propagation du signal
[Termes IGN] récepteur bifréquence
[Termes IGN] récepteur GNSS
[Termes IGN] résidu
[Termes IGN] traitement de données GNSS
[Termes IGN] varianceRésumé : (Auteur) The first-order ionospheric error is reduced in the dual-frequency Global Navigation Satellite Systems (GNSS). In this paper, the possibility of eliminating ionospheric higher-order errors in the multifrequency GNSS is explored. Since the second-order error associated with the geomagnetic field effect on the refractive index can be eliminated in dual-frequency measurements, we explore the possibility of eliminating third-order errors in triple-frequency GNSS in view of phase scintillations. A connection between the possibility of improving the multifrequency GNSS accuracy and diffraction effects in radio signal propagation through the randomly inhomogeneous ionosphere is shown. The numerical simulation has revealed that the systematic, residual ionospheric error is considerably reduced when we pass on from dual-frequency to triple-frequency measurements. The change in the residual error variance during such a transition depends however on the relationship between the inner scale of the turbulent spectrum of ionospheric irregularities and the Fresnel radius. Given the inner scale larger than the Fresnel radius, not only the systematic error, but also the standard deviation reduces when we pass on from dual-frequency to triple-frequency measurements. Otherwise, when the Fresnel radius exceeds the inner scale, the variance increases with increasing number of frequencies in use. Numéro de notice : A2011-165 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-010-0425-z Date de publication en ligne : 27/11/2010 En ligne : https://doi.org/10.1007/s00190-010-0425-z Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30943
in Journal of geodesy > vol 85 n° 3 (March 2011) . - pp 159 - 169[article]Réservation
Réserver ce documentExemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 266-2011031 RAB Revue Centre de documentation En réserve L003 Disponible Efficient estimation of variance and covariance components : A case study for GPS stochastic model evaluation / B. Li in IEEE Transactions on geoscience and remote sensing, vol 49 n° 1 Tome 1 (January 2011)
[article]
Titre : Efficient estimation of variance and covariance components : A case study for GPS stochastic model evaluation Type de document : Article/Communication Auteurs : B. Li, Auteur ; Y. Shen, Auteur ; L. Lou, Auteur Année de publication : 2011 Conférence : IGARSS 2009, International Geoscience And Remote Sensing Symposium 12/07/2009 17/07/2009 Le Cap Afrique du sud Proceedings IEEE Article en page(s) : pp 203 - 210 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] covariance
[Termes IGN] matrice de covariance
[Termes IGN] modèle stochastique
[Termes IGN] positionnement par GPS
[Termes IGN] varianceRésumé : (Auteur) The variance and covariance component estimation (VCE) has been extensively investigated. However, in real application, the bottleneck problem is the huge computation burden, particularly when many variance and covariance components are involved for many heterogeneous observations. The objective of this paper is to develop a new method allowing the efficient estimation of variance and covariance components. The core of the new method is to construct an orthogonal complement matrix of the coefficient matrix in a Gauss-Markov model using only the coefficient matrix itself. Therefore, the constructed matrix and the computed discrepancies of measurements with each other, which are the essential inputs for the VCE, are invariant in the iterative procedure of computing the variance and covariance components. As a result, the computation efficiency is significantly improved. As a case study, we apply the new method to evaluate the GPS stochastic model with 15 variance and covariance components demonstrating its superior performance. Comparing with the traditional VCE method, the equivalent results are achievable, and the computation efficiency is improved by 34.2%. In the future, much more sensors will be available, and plentiful data can be acquired. Therefore, the new method will be very promising to efficiently estimate the variance and covariance components of the measurements from the different sensors and reasonably balance their contributions to the fused solution, benefiting the higher time-resolution solutions. Numéro de notice : A2011-049 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2010.2054100 Date de publication en ligne : 12/08/2010 En ligne : https://doi.org/10.1109/TGRS.2010.2054100 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30830
in IEEE Transactions on geoscience and remote sensing > vol 49 n° 1 Tome 1 (January 2011) . - pp 203 - 210[article]Réservation
Réserver ce documentExemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 065-2011011A RAB Revue Centre de documentation En réserve L003 Disponible Applying time-dependent variance-based global sensitivity analysis to represent the dynamics of an agent-based model of land use change / A. Ligmann-Zielinska in International journal of geographical information science IJGIS, vol 24 n°11-12 (december 2010)
[article]
Titre : Applying time-dependent variance-based global sensitivity analysis to represent the dynamics of an agent-based model of land use change Type de document : Article/Communication Auteurs : A. Ligmann-Zielinska, Auteur ; L. Sun, Auteur Année de publication : 2010 Article en page(s) : pp 1829 - 1850 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale
[Termes IGN] analyse de sensibilité
[Termes IGN] changement d'occupation du sol
[Termes IGN] complexité
[Termes IGN] données spatiotemporelles
[Termes IGN] incertitude des données
[Termes IGN] modèle orienté agent
[Termes IGN] varianceRésumé : (Auteur) The growing body of knowledge on modeling land use systems points to epistemic uncertainty as one of the challenging obstacles in development and application of agent-based models (ABMs). To decrease outcome uncertainty, sensitivity analysis (SA) is performed as part of model verification and validation. Oftentimes, however, it is inadequately addressed, partly because of the lack of tools and techniques that focus on an explicit evaluation of ABM dynamics. The nonlinear processes, inherent in such models, necessitate longitudinal SA with time path investigation of input-output relationships of endogenous variables. In response to the outlined deficiencies, this study investigates the potential of time-dependent global sensitivity analysis (time-GSA) in examining the dynamics of outcome uncertainty of a simple ABM of land use change. Specifically, we apply first and total order sensitivity indices to decompose variance of output landscape fragmentation, apportioned to model inputs for multiple time steps and multiple realizations of the ABM. We focus the analysis on selected complex systems characteristics including preference uncertainty, path dependence, access to information, and magnitude of interactions and feedbacks. We conclude that the factor sensitivity measures vary significantly during model execution. Consequently, a static snapshot of ABM sensitivity, taken at the end of the simulation, is inadequate when deciding on factor prioritization and reduction. Assuming that ABM dynamics is a result of factor interaction, we observe a distinct time lag of nonlinearity, which unfolds after the formation of the seeds of development. Therefore, we argue for further application of time-GSA in ABM as one of the visual quantitative techniques contributing to evaluation of ABM nonlinearity. Numéro de notice : A2010-552 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/13658816.2010.490533 En ligne : https://doi.org/10.1080/13658816.2010.490533 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30744
in International journal of geographical information science IJGIS > vol 24 n°11-12 (december 2010) . - pp 1829 - 1850[article]Réservation
Réserver ce documentExemplaires(2)
Code-barres Cote Support Localisation Section Disponibilité 079-2010071 RAB Revue Centre de documentation En réserve L003 Disponible 079-2010072 RAB Revue Centre de documentation En réserve L003 Disponible The combination of GNSS-levelling data and gravimetric (quasi-) geoid heights in the presence of noise / R. Klees in Journal of geodesy, vol 84 n° 12 (December 2010)
[article]
Titre : The combination of GNSS-levelling data and gravimetric (quasi-) geoid heights in the presence of noise Type de document : Article/Communication Auteurs : R. Klees, Auteur ; I. Prutkin, Auteur Année de publication : 2010 Article en page(s) : pp 731 - 749 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] altitude normale
[Termes IGN] altitude orthométrique
[Termes IGN] bruit (théorie du signal)
[Termes IGN] champ de pesanteur local
[Termes IGN] collocation par moindres carrés
[Termes IGN] données GNSS
[Termes IGN] géoïde gravimétrique
[Termes IGN] hauteur ellipsoïdale
[Termes IGN] matrice de covariance
[Termes IGN] nivellement par GPS
[Termes IGN] problème des valeurs limites
[Termes IGN] Suisse
[Termes IGN] varianceRésumé : (Auteur) We propose a methodology for the combination of a gravimetric (quasi-) geoid with GNSS-levelling data in the presence of noise with correlations and/or spatially varying noise variances. It comprises two steps: first, a gravimetric (quasi-) geoid is computed using the available gravity data, which, in a second step, is improved using ellipsoidal heights at benchmarks provided by GNSS once they have become available. The methodology is an alternative to the integrated processing of all available data using least-squares techniques or least-squares collocation. Unlike the corrector-surface approach, the pursued approach guarantees that the corrections applied to the gravimetric (quasi-) geoid are consistent with the gravity anomaly data set. The methodology is applied to a data set comprising 109 gravimetric quasi-geoid heights, ellipsoidal heights and normal heights at benchmarks in Switzerland. Each data set is complemented by a full noise covariance matrix. We show that when neglecting noise correlations and/or spatially varying noise variances, errors up to 10% of the differences between geometric and gravimetric quasi-geoid heights are introduced. This suggests that if high-quality ellipsoidal heights at benchmarks are available and are used to compute an improved (quasi-) geoid, noise covariance matrices referring to the same datum should be used in the data processing whenever they are available. We compare the methodology with the corrector-surface approach using various corrector surface models. We show that the commonly used corrector surfaces fail to model the more complicated spatial patterns of differences between geometric and gravimetric quasi-geoid heights present in the data set. More flexible parametric models such as radial basis function approximations or minimum-curvature harmonic splines perform better. We also compare the proposed method with generalized least-squares collocation, which comprises a deterministic trend model, a random signal component and a random correlated noise component. Trend model parameters and signal covariance function parameters are estimated iteratively from the data using non-linear least-squares techniques. We show that the performance of generalized least-squares collocation is better than the performance of corrector surfaces, but the differences with respect to the proposed method are still significant. Numéro de notice : A2010-559 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-010-0406-2 Date de publication en ligne : 29/08/2010 En ligne : https://doi.org/10.1007/s00190-010-0406-2 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30751
in Journal of geodesy > vol 84 n° 12 (December 2010) . - pp 731 - 749[article]Réservation
Réserver ce documentExemplaires(2)
Code-barres Cote Support Localisation Section Disponibilité 266-02010121 SL Revue Centre de documentation Revues en salle Disponible 266-2010121 SL Revue Centre de documentation Revues en salle Disponible A comparison of recent Earth gravitational models with emphasis on their contribution in refining the gravity and geoid at continental or regional scale / D. Arabelos in Journal of geodesy, vol 84 n° 11 (November 2010)PermalinkCombinaison linéaire et l'intérêt de la troisième fréquence pour le positionnement en double différence par GPS / L. Tabti in XYZ, n° 124 (septembre - novembre 2010)PermalinkAnalyse des séries temporelles SLR du géocentre et des EOP basées sur les mesures des satellites LAGEOS1/2 et Starlette / Bachir Gourine in Bulletin des sciences géographiques, n° 25 (juin 2010)PermalinkApproximating covariance matrices estimated in multivariate models by estimated auto- and cross-covariances / Karl Rudolf Koch in Journal of geodesy, vol 84 n° 6 (June 2010)PermalinkThe Forward Propagation of Integrated System Component Errors within Airborne Lidar Data / T. Goulden in Photogrammetric Engineering & Remote Sensing, PERS, vol 76 n° 5 (May 2010)PermalinkConstruction of spherical harmonic series for the potential derivatives of arbitrary orders in the geocentric Earth-fixed reference frame / M. Petrovskaya in Journal of geodesy, vol 84 n° 3 (March 2010)PermalinkReal-time registration of airborne laser with sub-decimeter accuracy / Jan Skaloud in ISPRS Journal of photogrammetry and remote sensing, vol 65 n° 2 (March - April 2010)PermalinkIntroducing scale parameters for adjusting area objects in GIS based on least squares and variance component estimation / X. Tong in International journal of geographical information science IJGIS, vol 23 n°11-12 (november 2009)PermalinkConsideration of time-correlated errors in a Kalman filter applicable to GNSS / M.G. Potovello in Journal of geodesy, vol 83 n° 1 (January 2009)PermalinkCounting equivalent correlators: quantifying the number for GNSS acquisition engine architectures / A. Genghi in GPS world, vol 20 n° 1 (January 2009)Permalink