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Long-term prediction of polar motion using a combined SSA and ARMA model / Y. Shen in Journal of geodesy, vol 92 n° 3 (March 2018)  

Public [article]  inJournal of geodesy > vol 92 n° 3 (March 2018) . - pp 333 - 343 Titre : Long-term prediction of polar motion using a combined SSA and ARMA model Type de document : Article/Communication Auteurs : Y. Shen, Auteur ; Jinyun Guo, Auteur ; X. Liu, Auteur ; Qiaoli Kong, Auteur ; Linxi Guo, Auteur ; Li Wang, Auteur Année de publication : 2018 Article en page(s) : pp 333 - 343 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] analyse de spectre singulier [Termes IGN] analyse en composantes principales [Termes IGN] modèle de simulation [Termes IGN] mouvement du pôle Mots-clés libres : modèle ARMA Résumé : (Auteur) To meet the need for real-time and high-accuracy predictions of polar motion (PM), the singular spectrum analysis (SSA) and the autoregressive moving average (ARMA) model are combined for short- and long-term PM prediction. According to the SSA results for PM and the SSA prediction algorithm, the principal components of PM were predicted by SSA, and the remaining components were predicted by the ARMA model. In applying this proposed method, multiple sets of PM predictions were made with lead times of two years, based on an IERS 08 C04 series. The observations and predictions of the principal components correlated well, and the SSA + ARMA model effectively predicted the PM. For 360-day lead time predictions, the root-mean-square errors (RMSEs) of PMx and PMy were 20.67 and 20.42 mas, respectively, which were less than the 24.46 and 24.78 mas predicted by IERS Bulletin A. The RMSEs of PMx and PMy in the 720-day lead time predictions were 28.61 and 27.95 mas, respectively. Numéro de notice : A2018-061 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-017-1065-3 Date de publication en ligne : 12/09/2017 En ligne : https://doi.org/10.1007/s00190-017-1065-3 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89397 [article]

On detecting spatial categorical outliers / X. Liu in Geoinformatica, vol 18 n° 3 (July 2014)  

Public [article]  inGeoinformatica > vol 18 n° 3 (July 2014) . - pp 501 - 536 Titre : On detecting spatial categorical outliers Type de document : Article/Communication Auteurs : X. Liu, Auteur ; Feng Chen, Auteur ; Tien Lu, Auteur Année de publication : 2014 Article en page(s) : pp 501 - 536 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] détection d'anomalie [Termes IGN] valeur aberrante Résumé : (Auteur)Spatial outlier detection is an important research problem that has received much attentions in recent years. Most existing approaches are designed for numerical attributes, but are not applicable to categorical ones (e.g., binary, ordinal, and nominal) that are popular in many applications. The main challenges are the modeling of spatial categorical dependency as well as the computational efficiency. This paper presents the first outlier detection framework for spatial categorical data. Specifically, a new metric, named as Pair Correlation Ratio (PCR), is measured for each pair of category sets based on their co-occurrence frequencies at specific spatial distance ranges. The relevances among spatial objects are then calculated using PCR values with regard to their spatial distances. The outlierness for each object is defined as the inverse of the average relevance between an object and its spatial neighbors. Those objects with the highest outlier scores are returned as spatial categorical outliers. A set of algorithms are further designed for single-attribute and multi-attribute spatial categorical datasets. Extensive experimental evaluations on both simulated and real datasets demonstrated the effectiveness and efficiency of our proposed approaches. Numéro de notice : A2014-499 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1007/s10707-013-0188-9 Date de publication en ligne : 28/09/2013 En ligne : https://doi.org/10.1007/s10707-013-0188-9 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=74091 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
057-2014031	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Approximation theory applied to DEM vertical accuracy assessment / X. Liu in Transactions in GIS, vol 16 n° 3 (June 2012)  

Public [article]  inTransactions in GIS > vol 16 n° 3 (June 2012) . - pp 397 - 410 Titre : Approximation theory applied to DEM vertical accuracy assessment Type de document : Article/Communication Auteurs : X. Liu, Auteur ; P. Hu, Auteur ; H. Hu, Auteur ; J. Sherda, Auteur Année de publication : 2012 Article en page(s) : pp 397 - 410 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications photogrammétriques [Termes IGN] approximation [Termes IGN] estimation statistique [Termes IGN] interpolation linéaire [Termes IGN] modèle numérique de surface [Termes IGN] précision altimétrique [Termes IGN] précision du positionnement Résumé : (Auteur) Existing research on DEM vertical accuracy assessment uses mainly statistical methods, in particular variance and RMSE which are both based on the error propagation theory in statistics. This article demonstrates that error propagation theory is not applicable because the critical assumption behind it cannot be satisfied. In fact, the non-random, non-normal, and non-stationary nature of DEM error makes it very challenging to apply statistical methods. This article presents approximation theory as a new methodology and illustrates its application to DEMs created by linear interpolation using contour lines as the source data. Applying approximation theory, a DEM's accuracy is determined by the largest error of any point (not samples) in the entire study area. The error at a point is bounded by max(|?mode|+M2h2/8) where |?node| is the error in the source data used to interpolate the point, M2 is the maximum norm of the second-order derivative which can be interpreted as curvature, and h is the length of the line on which linear interpolation is conducted. The article explains how to compute each term and illustrates how this new methodology based on approximation theory effectively facilitates DEM accuracy assessment and quality control. Numéro de notice : A2012-283 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/j.1467-9671.2012.01343.x Date de publication en ligne : 28/05/2012 En ligne : https://doi.org/10.1111/j.1467-9671.2012.01343.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31729 [article]

Query-aware location anonymization for road networks / C. Chow in Geoinformatica, vol 15 n° 3 (July 2011)  

Public [article]  inGeoinformatica > vol 15 n° 3 (July 2011) . - pp 571 - 607 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 position Résumé : (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 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
057-2011031	RAB	Revue	Centre de documentation	En réserve L003	Disponible

An agent-based model for optimal land allocation (AgentLA) with a contiguity constraint / Y. Chen in International journal of geographical information science IJGIS, vol 24 n°7-8 (july 2010)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 24 n°7-8 (july 2010) . - pp 1269 - 1288 Titre : An agent-based model for optimal land allocation (AgentLA) with a contiguity constraint Type de document : Article/Communication Auteurs : Y. Chen, Auteur ; X. Li, Auteur ; X. Liu, Auteur ; et al., Auteur Année de publication : 2010 Article en page(s) : pp 1269 - 1288 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] agent (intelligence artificielle) [Termes IGN] allocation [Termes IGN] Canton (Kouangtoung) [Termes IGN] optimisation (mathématiques) [Termes IGN] participation du public [Termes IGN] programmation par contraintes Résumé : (Auteur) Spatial optimization is complex because it usually involves numerous spatial factors and constraints. The optimization becomes more challenging if a large set of spatial data with fine resolutions are used. This article presents an agent-based model for optimal land allocation (AgentLA) by maximizing the total amount of land-use suitability and the compactness of patterns. The essence of the optimization is based on the collective efforts of agents for formulating the optimal patterns. A local and global search strategy is proposed to inform the agents to select the sites properly. Three sets of hypothetical data were first used to verify the optimization effects. AgentLA was then applied to the solution of the actual land allocation optimization problems in Panyu city in the Pearl River Delta. The study has demonstrated that the proposed method has better performance than the simulated annealing method for solving complex spatial optimization problems. Experiments also indicate that the proposed model can produce patterns that are very close to the global optimums. Numéro de notice : A2010-329 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/13658810903401024 En ligne : https://doi.org/10.1080/13658810903401024 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30523 [article]

Exemplaires(2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
079-2010041	RAB	Revue	Centre de documentation	En réserve L003	Disponible
079-2010042	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Ant intelligence for solving optimal path-covering problems with multi-objectives / X. Li in International journal of geographical information science IJGIS, vol 23 n° 7-8 (july 2009)  

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Intelligent GIS for solving high-dimensional site selection problems using ant colony optimization techniques / X. Li in International journal of geographical information science IJGIS, vol 23 n°3-4 (march - april 2009)  

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Accuracy assessment of digital elevation models based on approximation theory / P. Hu in Photogrammetric Engineering & Remote Sensing, PERS, vol 75 n° 1 (January 2009)  

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An innovative method to classify remote-sensing images using Ant Colony Optimization / X. Liu in IEEE Transactions on geoscience and remote sensing, vol 46 n° 12 (December 2008)  

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A bottom-up approach to discover transition rules of cellular automata using ant intelligence / X. Liu in International journal of geographical information science IJGIS, vol 22 n°11-12 (november 2008)  

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Population-density estimation using regression and area-to-point residual kriging / X. Liu in International journal of geographical information science IJGIS, vol 22 n° 4-5 (april 2008)  

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Embedding sustainable development strategies in agent-based models for use as a planning tool / X. Li in International journal of geographical information science IJGIS, vol 22 n° 1-2 (february 2008)  

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LiDAR-derived high quality ground control information and DEM for image orthorectification / X. Liu in Geoinformatica, vol 11 n° 1 (March - May 2007)  

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An extended cellular automaton using case-based reasoning for simulating urban development in a large complex region / X. Li in International journal of geographical information science IJGIS, vol 20 n° 10 (november 2006)  

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Terrain complexity and uncertainties in grid-based digital terrain analysis / Q. Zhou in International journal of geographical information science IJGIS, vol 20 n° 10 (november 2006)  

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