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Dirichlet process based active learning and discovery of unknown classes for hyperspectral image classification / Hao Wu in IEEE Transactions on geoscience and remote sensing, vol 54 n° 8 (August 2016)
[article]
Titre : Dirichlet process based active learning and discovery of unknown classes for hyperspectral image classification Type de document : Article/Communication Auteurs : Hao Wu, Auteur ; Saurabh Prasad, Auteur Année de publication : 2016 Article en page(s) : pp 4882 - 4895 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] apprentissage automatique
[Termes IGN] classification
[Termes IGN] image hyperspectrale
[Termes IGN] problème de DirichletRésumé : (Auteur) Active learning is an area of significant ongoing research interest for the classification of remotely sensed data, where obtaining efficient training data is both time consuming and expensive. The goal of active learning is to achieve high classification performance by querying as few samples as possible from a large unlabeled data pool. Traditional active learning frameworks all assume the existence of labeled samples for all classes of interest. However, in real-world applications, the unlabeled data pool may contain data from unknown classes that we are not aware of in advance, and a quick detection of them is useful for enriching our training set. In this scenario, traditional active learning methods may not effectively and rapidly detect the unknown classes. We proposed an active learning framework which provides robust classification performance with minimum manual labeling effort while simultaneously discovering unknown (missing) classes. The discovery of unknown classes is particularly suited to an active learning framework where an annotator is in the loop. A Dirichlet process mixture model is utilized in our proposed method to cluster the labeled and unlabeled samples as a whole. If unknown classes exist, they will emerge as new clusters which are different from other existing clusters occupied by known classes, and then, the proposed query strategy will give priority to querying samples in the new clusters. We present experimental results with hyperspectral data to show that our method provides better classification performance compared to existing active learning methods with or without unknown classes. Numéro de notice : A2016-892 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2016.2552507 En ligne : http://dx.doi.org/10.1109/TGRS.2016.2552507 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83072
in IEEE Transactions on geoscience and remote sensing > vol 54 n° 8 (August 2016) . - pp 4882 - 4895[article]
Titre : Brownian motion, martingales, and stochastic calculus Type de document : Guide/Manuel Auteurs : Jean-François Le Gall, Auteur Editeur : Springer International Publishing Année de publication : 2016 Importance : 273 p. Format : 16 x 24 cm ISBN/ISSN/EAN : 978-3-319-31089-3 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Mathématique
[Termes IGN] chaîne de Markov
[Termes IGN] fonction harmonique
[Termes IGN] mouvement brownien
[Termes IGN] probabilités
[Termes IGN] stochastiqueRésumé : (éditeur) This book offers a rigorous and self-contained presentation of stochastic integration and stochastic calculus within the general framework of continuous semimartingales. The main tools of stochastic calculus, including Itô's formula, the optional stepping theorem and Girsanov's theorem, are treated in detail alongside many illustrative examples. The book also contains an introduction to Markov processes, with applications to solutions of stochastic differential equations and to connections between Brownian motion and partial differential equations. The theory of local times of semimartingales is discussed in the last chapter. Since its invention by Itô, stochastic calculus has proven to be one of the most important techniques of modern probability theory, and has been used in the most recent theoretical advances as well as in applications to other fields such as mathematical finance. Brownian Motion, Martingales, and Stochastic Calculus provides a strong theoretical background to the reader interested in such developments. Beginning graduate or advanced undergraduate students will benefit from this detailed approach to an essential area of probability theory. The emphasis is on concise and efficient presentation, without any concession to mathematical rigor. The material has been taught by the author for several years in graduate courses at two of the most prestigious French universities. The fact that proofs are given with full details makes the book particularly suitable for self-study. The numerous exercises help the reader to get acquainted with the tools of stochastic calculus. Numéro de notice : 26586 Affiliation des auteurs : non IGN Thématique : MATHEMATIQUE Nature : Manuel En ligne : https://doi.org/10.1007/978-3-319-31089-3 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95220 Contribution of mass density heterogeneities to the quasigeoid-to-geoid separation / Robert Tenzer in Journal of geodesy, vol 90 n° 1 (January 2016)
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Titre : Contribution of mass density heterogeneities to the quasigeoid-to-geoid separation Type de document : Article/Communication Auteurs : Robert Tenzer, Auteur ; Christian Hirt, Auteur ; Pavel Novák, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 65-80 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] anomalie de pesanteur
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] harmonique sphérique
[Termes IGN] masse de la Terre
[Termes IGN] modèle de densité
[Termes IGN] quasi-géoïde
[Termes IGN] topographieRésumé : (auteur) The geoid-to-quasigeoid separation is often computed only approximately as a function of the simple planar Bouguer gravity anomaly and the height of the computation point while disregarding the contributions of terrain geometry and anomalous topographic density as well as the sub-geoid masses. In this study we demonstrate that these contributions are significant and, therefore, should be taken into consideration when investigating the relation between the normal and orthometric heights particularly in the mountainous, polar and geologically complex regions. These contributions are evaluated by applying the spectral expressions for gravimetric forward modelling and using the EIGEN-6C4 gravity model, the Earth2014 datasets of terrain, ice thickness and inland bathymetry and the CRUST1.0 sediment and (consolidated) crustal density data. Since the global crustal density models currently available (e.g. CRUST1.0) have a limited accuracy and resolution, the comparison of individual density contributions is—for consistency—realized with a limited spectral resolution up to a spherical harmonic degree 360 (or 180). The results reveal that the topographic contribution globally varies between −0.33 and 0.57 m, with maxima in Himalaya and Tibet. The contribution of ice considerably modifies the geoid-to-quasigeoid separation over large parts of Antarctica and Greenland, where it reaches ∼0.2 m. The contributions of sediments and bedrock are less pronounced, with the values typically varying only within a few centimetres. These results, however, have still possibly large uncertainties due to the lack of information on the actual sediment and bedrock density. The contribution of lakes is mostly negligible; its maxima over the Laurentian Great Lakes and the Baikal Lake reach only several millimetres. The contribution of the sub-geoid masses is significant. It is everywhere negative and reaches extreme values of −4.43 m. According to our estimates, the geoid-to-quasigeoid separation globally varies within −4.19 and 0.26 m while the corresponding values computed according to a classical definition are only negative and reach extreme values of −3.5 m. A comparison of these results reveals that inaccuracies caused by disregarding the terrain geometry and mass density heterogeneities distributed within the topography and below the geoid surface can reach ±2 m or more in the mountainous regions. Numéro de notice : A2016-019 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-015-0858-5 Date de publication en ligne : 01/10/2015 En ligne : https://doi.org/10.1007/s00190-015-0858-5 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=79466
in Journal of geodesy > vol 90 n° 1 (January 2016) . - pp 65-80[article]Traitement du signal marégraphique par analyse harmonique pour la détermination d'une référence altimétrique pour l'Algérie / A. Rami in Bulletin des sciences géographiques, n° 30 (2015 - 2016)
[article]
Titre : Traitement du signal marégraphique par analyse harmonique pour la détermination d'une référence altimétrique pour l'Algérie Type de document : Article/Communication Auteurs : A. Rami, Auteur ; M. Nechimi, Auteur ; M. Haddad, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 2 - 10 Note générale : biblographie Langues : Français (fre) Descripteur : [Termes IGN] Algérie
[Termes IGN] analyse harmonique
[Termes IGN] analyse spectrale
[Termes IGN] données marégraphiques
[Termes IGN] niveau moyen des mers
[Termes IGN] série temporelle
[Termes IGN] système de référence altimétrique
[Termes IGN] variation temporelle
[Vedettes matières IGN] AltimétrieRésumé : (auteur) Afin de déterminer une référence altimétrique nationale pour l'Algérie, l'Institut National de Cartographie et de Télédétection (INCT) a procédé à l'installation de trois marégraphes numériques à acquisition automatique (Log_aLevel) aux ports d'Alger, de Jijel et d'Oran. L'analyse harmonique des données marégraphiques issues de ces trois stations, nous a permis la détermination des composantes harmoniques de la marée et du niveau moyen de la mer au niveau de chaque port. Le niveau moyen de la mer calculé, par traitement d'une année de séries temporelles de la marée pour chaque station, est de 40.6 cm au port d'Alger, 39.8 cm au port de Jijel et 58 cm au port d'Oran. L'analyse spectrale a permis de localiser les amplitudes significatives relatives aux variations temporelles de la marée et donc de détecter le type de marée à chaque station. Numéro de notice : A2016-462 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81465
in Bulletin des sciences géographiques > n° 30 (2015 - 2016) . - pp 2 - 10[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 253-2016011 SL Revue Centre de documentation Revues en salle Disponible A moving weighted harmonic analysis method for reconstructing high-quality SPOT VEGETATION NDVI time-series data / Gang Yang in IEEE Transactions on geoscience and remote sensing, vol 53 n° 11 (November 2015)
[article]
Titre : A moving weighted harmonic analysis method for reconstructing high-quality SPOT VEGETATION NDVI time-series data Type de document : Article/Communication Auteurs : Gang Yang, Auteur ; Huanfeng Shen, Auteur ; Liangpei Zhang, Auteur ; et al., Auteur Année de publication : 2015 Article en page(s) : pp 6008 - 6021 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] analyse diachronique
[Termes IGN] analyse harmonique
[Termes IGN] Chine
[Termes IGN] filtrage numérique d'image
[Termes IGN] image SPOT-Végétation
[Termes IGN] Normalized Difference Vegetation Index
[Termes IGN] occupation du sol
[Termes IGN] série temporelle
[Termes IGN] surveillance de la végétationRésumé : (Auteur) Global or regional environmental change is of wide concern. Extensive studies have indicated that long-term vegetation cover change is one of the most important factors reflecting environmental change, and normalized difference vegetation index (NDVI) time-series data sets have been widely used in vegetation dynamic change monitoring. However, the significant residual effects and noise levels impede the application of NDVI time-series data in environmental change research. This study develops a novel and robust filter method, i.e., the moving weighted harmonic analysis (MWHA) method, which incorporates a moving support domain to assign the weights for all the points, making the determination of the frequency number much easier. Additionally, a four-step process flow is designed to make the data approach the upper NDVI envelope, so that the actual change in the vegetation can be detected. A total of 487 test pixels selected from SPOT VEGETATION 10-day MVC NDVI time-series data from January 1999 to December 2001 were used to illustrate the effectiveness of the new method by comparing the MWHA results with the results of another four existing methods. Finally, the long-term SPOT VEGETATION 10-day maximum-value compositing (MVC) NDVI time series for China from April 1998 to May 2014 was reconstructed by the use of the proposed method, and a test region in China was utilized to validate the effectiveness of the proposed MWHA method. All the results indicate that the reconstructed high-quality NDVI time series fits the actual growth profile of the vegetation and is suitable for use in further remote sensing applications. Numéro de notice : A2015-771 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2015.2431315 Date de publication en ligne : 02/06/2015 En ligne : https://doi.org/10.1109/TGRS.2015.2431315 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=78827
in IEEE Transactions on geoscience and remote sensing > vol 53 n° 11 (November 2015) . - pp 6008 - 6021[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 065-2015111 SL Revue Centre de documentation Revues en salle Disponible A surface spherical harmonic expansion of gravity anomalies on the ellipsoid / S.J. Claessens in Journal of geodesy, vol 89 n° 10 (october 2015)PermalinkReducing leakage error in GRACE-observed long-term ice mass change: a case study in West Antarctica / J. L. Chen in Journal of geodesy, vol 89 n° 9 (september 2015)PermalinkAccuracy of unmodified Stokes’ integration in the R-C-R procedure for geoid computation / Zahra Ismaïl in Journal of applied geodesy, vol 9 n° 2 (June 2015)PermalinkRegional vertical total electron content (VTEC) modeling together with satellite and receiver differential code biases (DCBs) using semi-parametric multivariate adaptive regression B-splines (SP-BMARS) / Murat Durmaz in Journal of geodesy, vol 89 n° 4 (April 2015)PermalinkSHPTS: towards a new method for generating precise global ionospheric TEC map based on spherical harmonic and generalized trigonometric series functions / Zishen Li in Journal of geodesy, vol 89 n° 4 (April 2015)PermalinkPermalinkEmpirical model of the gravitational field generated by the oceanic lithosphere / Robert Tenzer in Advances in space research, vol 55 n° 1 ([01/01/2015])PermalinkExtracting tidal frequencies using multivariate harmonic analysis of sea level height time series / Ali Reza Amiri-Simkooei in Journal of geodesy, vol 88 n° 10 (October 2014)PermalinkReducing the draconitic errors in GNSS geodetic products / C.J. Rodriguez-Solano in Journal of geodesy, vol 88 n° 6 (June 2014)PermalinkComparison among three harmonic analysis techniques on the sphere and the ellipsoid / Hussein Abd-Elmotaal in Journal of applied geodesy, vol 8 n° 1 (April 2014)Permalink