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Dynamic positioning configuration and its first-order optimization / Shuqiang Xue in Journal of geodesy, vol 88 n° 2 (February 2014)
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Titre : Dynamic positioning configuration and its first-order optimization Type de document : Article/Communication Auteurs : Shuqiang Xue, Auteur ; Yuanxi Yang, Auteur ; et al., Auteur Année de publication : 2014 Article en page(s) : pp 127 - 143 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] espace de Hilbert
[Termes IGN] optimisation (mathématiques)
[Termes IGN] positionnement par GPS
[Termes IGN] réseau de premier ordre
[Termes IGN] réseau géodésiqueRésumé : (Auteur) Traditional geodetic network optimization deals with static and discrete control points. The modern space geodetic network is, on the other hand, composed of moving control points in space (satellites) and on the Earth (ground stations). The network configuration composed of these facilities is essentially dynamic and continuous. Moreover, besides the position parameter which needs to be estimated, other geophysical information or signals can also be extracted from the continuous observations. The dynamic (continuous) configuration of the space network determines whether a particular frequency of signals can be identified by this system. In this paper, we employ the functional analysis and graph theory to study the dynamic configuration of space geodetic networks, and mainly focus on the optimal estimation of the position and clock-offset parameters. The principle of the D-optimization is introduced in the Hilbert space after the concept of the traditional discrete configuration is generalized from the finite space to the infinite space. It shows that the D-optimization developed in the discrete optimization is still valid in the dynamic configuration optimization, and this is attributed to the natural generalization of least squares from the Euclidean space to the Hilbert space. Then, we introduce the principle of D-optimality invariance under the combination operation and rotation operation, and propose some D-optimal simplex dynamic configurations: (1) (Semi) circular configuration in 2-dimensional space; (2) the D-optimal cone configuration and D-optimal helical configuration which is close to the GPS constellation in 3-dimensional space. The initial design of GPS constellation can be approximately treated as a combination of 24 D-optimal helixes by properly adjusting the ascending node of different satellites to realize a so-called Walker constellation. In the case of estimating the receiver clock-offset parameter, we show that the circular configuration, the symmetrical cone configuration and helical curve configuration are still D-optimal. It shows that the given total observation time determines the optimal frequency (repeatability) of moving known points and vice versa, and one way to improve the repeatability is to increase the rotational speed. Under the Newton’s law of motion, the frequency of satellite motion determines the orbital altitude. Furthermore, we study three kinds of complex dynamic configurations, one of which is the combination of D-optimal cone configurations and a so-called Walker constellation composed of D-optimal helical configuration, the other is the nested cone configuration composed of n cones, and the last is the nested helical configuration composed of n orbital planes. It shows that an effective way to achieve high coverage is to employ the configuration composed of a certain number of moving known points instead of the simplex configuration (such as D-optimal helical configuration), and one can use the D-optimal simplex solutions or D-optimal complex configurations in any combination to achieve powerful configurations with flexile coverage and flexile repeatability. Alternately, how to optimally generate and assess the discrete configurations sampled from the continuous one is discussed. The proposed configuration optimization framework has taken the well-known regular polygons (such as equilateral triangle and quadrangular) in two-dimensional space and regular polyhedrons (regular tetrahedron, cube, regular octahedron, regular icosahedron, or regular dodecahedron) into account. It shows that the conclusions made by the proposed technique are more general and no longer limited by different sampling schemes. By the conditional equation of D-optimal nested helical configuration, the relevance issues of GNSS constellation optimization are solved and some examples are performed by GPS constellation to verify the validation of the newly proposed optimization technique. The proposed technique is potentially helpful in maintenance and quadratic optimization of single GNSS of which the orbital inclination and the orbital altitude change under the precession, as well as in optimally nesting GNSSs to perform global homogeneous coverage of the Earth. Numéro de notice : A2014-139 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-013-0683-7 Date de publication en ligne : 03/12/2013 En ligne : https://doi.org/10.1007/s00190-013-0683-7 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=33044
in Journal of geodesy > vol 88 n° 2 (February 2014) . - pp 127 - 143[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 266-2014021 SL Revue Centre de documentation Revues en salle Disponible Blind evaluation of location based queries using space transformation to preserve location privacy / Ali Khshgozaran in Geoinformatica, vol 17 n° 4 (October 2013)
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Titre : Blind evaluation of location based queries using space transformation to preserve location privacy Type de document : Article/Communication Auteurs : Ali Khshgozaran, Auteur ; Houtan Shirani-Mehr, Auteur ; Cyrus Shahabi, Auteur Année de publication : 2013 Article en page(s) : pp 599 - 634 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale
[Termes IGN] espace de Hilbert
[Termes IGN] géopositionnement
[Termes IGN] plus proche voisin, algorithme du
[Termes IGN] protection de la vie privée
[Termes IGN] requête spatiale
[Termes IGN] service fondé sur la position
[Termes IGN] utilisateurRésumé : (Auteur) In this paper, we propose a fundamental approach to perform the class of Range and Nearest Neighbor (NN) queries, the core class of spatial queries used in location-based services, without revealing any location information about the query in order to preserve users’ private location information. The idea behind our approach is to utilize the power of one-way transformations to map the space of all objects and queries to another space and resolve spatial queries blindly in the transformed space. Traditional encryption based techniques, solutions based on the theory of private information retrieval, or the recently proposed anonymity and cloaking based approaches cannot provide stringent privacy guarantees without incurring costly computation and/or communication overhead. In contrast, we propose efficient algorithms to evaluate KNN and range queries privately in the Hilbert transformed space. We also propose a dual curve query resolution technique which further reduces the costs of performing range and KNN queries using a single Hilbert curve. We experimentally evaluate the performance of our proposed range and KNN query processing techniques and verify the strong level of privacy achieved with acceptable computation and communication overhead. Numéro de notice : A2013-511 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1007/s10707-012-0172-9 Date de publication en ligne : 29/11/2012 En ligne : https://doi.org/10.1007/s10707-012-0172-9 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32649
in Geoinformatica > vol 17 n° 4 (October 2013) . - pp 599 - 634[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 057-2013041 RAB Revue Centre de documentation En réserve L003 Disponible Spectral unmixing in multiple-kernel Hilbert space for hyperspectral imagery / Yanfeng Gu in IEEE Transactions on geoscience and remote sensing, vol 51 n° 7 Tome 1 (July 2013)
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Titre : Spectral unmixing in multiple-kernel Hilbert space for hyperspectral imagery Type de document : Article/Communication Auteurs : Yanfeng Gu, Auteur ; Shizhe Wang, Auteur ; Xiuping Jia, Auteur Année de publication : 2013 Article en page(s) : pp 3968 - 3981 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] analyse des mélanges spectraux
[Termes IGN] apprentissage automatique
[Termes IGN] classification par séparateurs à vaste marge
[Termes IGN] espace de Hilbert
[Termes IGN] image AVIRIS
[Termes IGN] image hyperspectraleRésumé : (Auteur) In this paper, we address a spectral unmixing problem for hyperspectral images by introducing multiple-kernel learning (MKL) coupled with support vector machines. To effectively solve issues of spectral unmixing, an MKL method is explored to build new boundaries and distances between classes in multiple-kernel Hilbert space (MKHS). Integrating reproducing kernel Hilbert spaces (RKHSs) spanned by a series of different basis kernels in MKHS is able to provide increased power in handling general nonlinear problems than traditional single-kernel learning in RKHS. The proposed method is developed to solve multiclass unmixing problems. To validate the proposed MKL-based algorithm, both synthetic data and real hyperspectral image data were used in our experiments. The experimental results demonstrate that the proposed algorithm has a strong ability to capture interclass spectral differences and improve unmixing accuracy, compared to the state-of-the-art algorithms tested. Numéro de notice : A2013-371 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2012.2227757 En ligne : https://doi.org/10.1109/TGRS.2012.2227757 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32509
in IEEE Transactions on geoscience and remote sensing > vol 51 n° 7 Tome 1 (July 2013) . - pp 3968 - 3981[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 065-2013071A RAB Revue Centre de documentation En réserve L003 Disponible Query-aware location anonymization for road networks / C. Chow in Geoinformatica, vol 15 n° 3 (July 2011)
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Titre : Query-aware location anonymization for road networks Type de document : Article/Communication Auteurs : C. Chow, Auteur ; M. Mokbel, Auteur ; Jie Bao, Auteur ; X. Liu, Auteur Année de publication : 2011 Article en page(s) : pp 571 - 607 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale
[Termes IGN] espace euclidien
[Termes IGN] requête spatiale
[Termes IGN] réseau routier
[Termes IGN] service fondé sur la positionRésumé : (Auteur) Recently, several techniques have been proposed to protect the user location privacy for location-based services in the Euclidean space. Applying these techniques directly to the road network environment would lead to privacy leakage and inefficient query processing. In this paper, we propose a new location anonymization algorithm that is designed specifically for the road network environment. Our algorithm relies on the commonly used concept of spatial cloaking, where a user location is cloaked into a set of connected road segments of a minimum total length L including at least K users. Our algorithm is “query-aware” as it takes into account the query execution cost at a database server and the query quality, i.e., the number of objects returned to users by the database server, during the location anonymization process. In particular, we develop a new cost function that balances between the query execution cost and the query quality. Then, we introduce two versions of our algorithm, namely, pure greedy and randomized greedy, that aim to minimize the developed cost function and satisfy the user specified privacy requirements. To accommodate intervals with a high workload, we introduce a shared execution paradigm that boosts the scalability of our location anonymization algorithm and the database server to support large numbers of queries received in a short time period. Extensive experimental results show that our algorithms are more efficient and scalable than the state-of-the-art technique, in terms of both query execution cost and query quality. The results also show that our algorithms have very strong resilience to two privacy attacks, namely, the replay attack and the center-of-cloaked-area attack. Numéro de notice : A2011-212 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1007/s10707-010-0117-0 Date de publication en ligne : 06/11/2010 En ligne : https://doi.org/10.1007/s10707-010-0117-0 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30990
in Geoinformatica > vol 15 n° 3 (July 2011) . - pp 571 - 607[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 057-2011031 RAB Revue Centre de documentation En réserve L003 Disponible Mathématiques pour le traitement du signal / M. Bergounioux (2010)
Titre : Mathématiques pour le traitement du signal : cours et exercices corrigés Type de document : Guide/Manuel Auteurs : M. Bergounioux, Auteur Editeur : Paris : Dunod Année de publication : 2010 Collection : Sciences Sup Sous-collection : Mathématiques Importance : 311 p. Format : 17 x 24 cm ISBN/ISSN/EAN : 978-2-10-054781-4 Note générale : Bibliographie Langues : Français (fre) Descripteur : [Vedettes matières IGN] Traitement du signal
[Termes IGN] analyse spectrale
[Termes IGN] distribution de Poisson
[Termes IGN] échantillonnage de signal
[Termes IGN] espace de Hilbert
[Termes IGN] filtrage du signal
[Termes IGN] transformation de Fourier
[Termes IGN] transformation de Laplace
[Termes IGN] transformation en ondelettesIndex. décimale : 24.20 Traitement du signal Résumé : (Editeur) Cet ouvrage est destiné aux étudiants en Master de mathématiques appliquées, aux élèves ingénieurs et aux candidats au CAPES ou à l'agrégation de mathématiques.
Le cours présente les fondements du traitement du signal du point de vue déterministe et reste donc très généraliste. Les pré-requis sont rappelés, l'ouvrage étant conçu pour être " auto-suffisant " L'analyse spectrale (séries de Fourier, transformation de Fourier, de Laplace) y est présentée pour des signaux continus (analogiques) et discrets (numériques). Les notions de filtrage, échantillonnage, temps-fréquence et temps échelle sont présentées dans des chapitres séparés. Enfin, une brève introduction au traitement de la parole illustre le propos de l'ouvrage.
Des exercices et leurs corrigés, ainsi que des travaux pratiques permettent de se préparer efficacement aux épreuves.Note de contenu : - ANALYSE SPECTRALE DES SIGNAUX UNIDIMENSIONNELS
- ANALYSE CORRELATIVE DES SIGNAUX
- FILTRAGE
- ECHANTILLONNAGE
- ANALYSE TEMPS-FREQUENCE
- ANALYSE TEMPS-ECHELLE, ONDELETTES
- INTRODUCTION A L'ANALYSE VOCALE
- ANNEXE 1 : ESPACES DE HILBERT
- ANNEXE 2 : NOTATIONSNuméro de notice : 20514 Affiliation des auteurs : non IGN Thématique : IMAGERIE/POSITIONNEMENT Nature : Manuel de cours Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=46802 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 20514-01 24.20 Livre Centre de documentation Physique Disponible Morphologie urbaine et réseau : Etude des discontinuités et des ruptures induites par le réseau de circulation à l'aide du modèle Remus / Dominique Badariotti in Revue internationale de géomatique, vol 19 n° 1 (mars – mai 2009)PermalinkDetection of multi-scale clusters in network space / S. Shiode in International journal of geographical information science IJGIS, vol 23 n° 1-2 (january 2009)PermalinkPermalinkSensitivity analysis of spatially aggregated responses: a gradient-based method / F. Pantus in International journal of geographical information science IJGIS, vol 22 n° 4-5 (april 2008)PermalinkÉtude comparative de différentes méthodes d'estimation / Samuel Nahmani (2008)PermalinkPermalinkMathématiques pour la modélisation géométrique, la représentation 3D et la synthèse d'images / L. Garnier (2007)PermalinkPermalinkAlgèbre linéaire et géométrie / Luc Jolivet (2005)PermalinkMathématiques tout-en-un PC PSI / Claude Deschamps (2005)Permalink