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Optimal management of larch (Larix olgensis A. Henry) plantations in Northeast China when timber production and carbon stock are considered / Wei Peng in Annals of Forest Science, vol 75 n° 1 (March 2018)
[article]
Titre : Optimal management of larch (Larix olgensis A. Henry) plantations in Northeast China when timber production and carbon stock are considered Type de document : Article/Communication Auteurs : Wei Peng, Auteur ; Timo Pukkala, Auteur ; Xingji Jin, Auteur ; Fengri Li, Auteur Année de publication : 2018 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] Chine
[Termes IGN] éclaircie (sylviculture)
[Termes IGN] économie forestière
[Termes IGN] Larix olgensis
[Termes IGN] modèle dynamique
[Termes IGN] plantation forestière
[Termes IGN] production agricole végétale
[Termes IGN] puits de carbone
[Termes IGN] ressources forestières
[Termes IGN] volume en bois
[Vedettes matières IGN] Végétation et changement climatiqueRésumé : (Auteur) Key message : The optimal management of larch (Larix olgensis) plantations in Northeast China consisted of 2 or 3 thinnings and a rotation length of 55–61 years when economic profitability, wood production, and carbon sequestration were simultaneously maximized. Wood production ranged from 5.4 to 11.7 m3 ha−1 a−1, depending on site quality.
Context: L. olgensis is an important tree species in the northeast forest region of China, playing a significant role in the establishment of fast-growing and high-yielding plantation forests in China. However, the management of these plantations has not been optimized in previous studies.
Aims: The objective of the study was to find the optimal combinations of thinning times, thinning types, and rotation length for L. olgensis stands when both timber production and carbon stock are considered.
Methods: First, a growth and yield model was developed to simulate the dynamics of larch plantations. Then, the models were linked with the Hooke and Jeeves optimization algorithm to optimize forest management for two commonly used planting densities and three site qualities.
Results: Two thinnings were found to be suitable for larch plantations when the stand density at 10 years was 2125 trees/ha (corresponding to a planting density of 2500 trees/ha) whereas three thinnings were recommended when the density at 10 years was 2800 trees/ha (planting density of 3300 trees/ha). When the stand density was 2800 trees/ha, the optimal rotation length was 61, 58, and 55 years for site indices (SI) 12, 16, and 20 m (dominant height at 30 years), respectively. The mean annual wood production was 5.4 m3 ha−1 for SI 12, 8.2 m3 ha−1 for SI 16, and 11.7 m3 ha−1 for SI 20. The results were nearly the same for the lower initial stand density. The better the site quality of the stand, the earlier the thinnings were conducted.
Conclusion: In multifunctional forestry, optimal rotation lengths of larch plantations were 10–20 years longer than advised in the current silvicultural recommendations for Northeast China.Numéro de notice : A2018-320 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s13595-018-0739-1 Date de publication en ligne : 04/06/2018 En ligne : https://doi.org/10.1007/s13595-018-0739-1 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=90455
in Annals of Forest Science > vol 75 n° 1 (March 2018)[article]Morphodynamic model for predicting beach changes based on Bagnold's concept and its applications / Takaaki Uda (2018)
Titre : Morphodynamic model for predicting beach changes based on Bagnold's concept and its applications Type de document : Monographie Auteurs : Takaaki Uda, Éditeur scientifique ; et al., Auteur Editeur : London [UK] : IntechOpen Année de publication : 2018 Importance : 208 p. Format : 19 x 27 cm ISBN/ISSN/EAN : 978-1-78984-946-2 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Océanographie
[Termes IGN] ensablement
[Termes IGN] littoral
[Termes IGN] modèle de simulation
[Termes IGN] modèle dynamique
[Termes IGN] modélisation 3D
[Termes IGN] montée du niveau de la mer
[Termes IGN] plage
[Termes IGN] trait de côteRésumé : (éditeur) The authors have developed models for predicting beach changes applicable to various problems on real coasts. One of them is the contour-line-change model to predict long-term beach changes caused by the imbalance in longshore sand transport, which is a kind of N-line model. Because the calculation of the nearshore current is not needed in this model, and the computational load is small, it has an advantage in the prediction of long-term topographic changes on an extensive coast. However, the handling of boundary conditions becomes difficult when offshore coastal structures are constructed in a complicated manner, and in this regard the so-called 3D model has an advantage. Taking this point into account, the authors developed a morphodynamic model (BG model) by applying the concept of the equilibrium slope and the energetics approach, in which depth changes on 2D horizontal grids are calculated. Note de contenu : 1- Introductory chapter: Morphodynamic model for predicting beach changes based on Bagnold’s concept and its applications
2- Derivation of the BG model
3- Eight types of BG models and discretization
4- Prediction of typical beach changes owing to human activities
5- Beach changes on coast subject to waves and seaward or shoreward strong currents
6- Formation of sand spit and bay barrier
7- Interaction of sandy islands
8- Formation of cuspate foreland
9- Segmentation and merging of closed water bodies by wind wavesNuméro de notice : 25960 Affiliation des auteurs : non IGN Nature : Recueil / ouvrage collectif DOI : 10.5772/66722 En ligne : https://doi.org/10.5772/66722 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96499 Sparse signal modeling: Application to image compression, Image error concealment and compressed sensing / Ali Akbari (2018)
Titre : Sparse signal modeling: Application to image compression, Image error concealment and compressed sensing Type de document : Thèse/HDR Auteurs : Ali Akbari, Auteur Editeur : Paris : Sorbonne Université Année de publication : 2018 Importance : 158 p. Format : 21 x 30 cm Note générale : bibliographie
Thèse de Doctorat de Traitement du signal et de l’image, Sorbonne UniversitéLangues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement du signal
[Termes IGN] acquisition comprimée
[Termes IGN] compensation
[Termes IGN] compression d'image
[Termes IGN] modélisation
[Termes IGN] problème inverse
[Termes IGN] reconstruction d'image
[Termes IGN] représentation parcimonieuse
[Termes IGN] théorie du signalIndex. décimale : THESE Thèses et HDR Résumé : (auteur) Signal models are a cornerstone of contemporary signal and image processing methodology. In this report, two particular signal modeling methods, called analysis and synthesis sparse representation, are studied which have been proven to be effective for many signals, such as natural images, and successfully used in a wide range of applications. Both models represent signals in terms of linear combinations of an underlying set, called dictionary, of elementary signals known as atoms. The driving force behind both models is sparsity of the representation coefficients, i.e. the rapid decay of the representation coefficients over the dictionary. On the other hands, the dictionary choice determines the success of the entire model. According to these two signal models, there have been two main disciplines of dictionary designing; harmonic analysis approach and machine learning methodology. The former leads to designing the dictionaries with easy and fast implementation, while the latter provides a simple and expressive structure for designing adaptable and efficient dictionaries. The main goal of this thesis is to provide new applications to these signal modeling methods by addressing several problems from various perspectives. It begins with the direct application of the sparse representation, i.e. image compression. The line of research followed in this area is the synthesis-based sparse representation approach in the sense that the dictionary is not fixed and predefined, but learned from training data and adapted to data, yielding a more compact representation. A new Image codec based on adaptive sparse representation over a trained dictionary is proposed, wherein different sparsity levels are assigned to the image patches belonging to the salient regions, being more conspicuous to the human visual system. Experimental results show that the proposed method outperforms the existing image coding standards, such as JPEG and JPEG2000, which use an analytic dictionary, as well as the state-of-the-art codecs based on the trained dictionaries. In the next part of thesis, it focuses on another important application of the sparse signal modeling, i.e. solving inverse problems, especially for error concealment (EC), wherein a corrupted image is reconstructed from the incomplete data, and Compressed Sensing recover, where an image is reconstructed from a limited number of random measurements. Signal modeling is usually used as a prior knowledge about the signal to solve these NP-hard problems. In this thesis, inspired by the analysis and synthesis sparse models, these challenges are transferred into two distinct sparse recovery frameworks and several recovery methods are proposed. Compared with the state-of-the-art EC and CS algorithms, experimental results show that the proposed methods show better reconstruction performance in terms of objective and subjective evaluations. This thesis is finalized by giving some conclusions and introducing some lines for future works. Note de contenu : 1- Introduction
2- Sparsity-based signal models
3- Image compressed sensing recovery
4- Receiver-based error concealment based on synthesis sparse recovery
5- Transmitter-based error concealment based on sparse recovery
6- Sparse representation-based image compression
7- Conclusion and future directionsNuméro de notice : 25937 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Thèse française Note de thèse : Thèse de Doctorat : Spécialité : Traitement du signal et de l’image : Paris : 2018 nature-HAL : Thèse DOI : sans En ligne : http://www.theses.fr/2018SORUS461 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96286 Toward a systematic integration of optical remote sensing for inland waters studies / Vincent Maurice Nouchi (2018)
Titre : Toward a systematic integration of optical remote sensing for inland waters studies Type de document : Thèse/HDR Auteurs : Vincent Maurice Nouchi, Auteur ; Alfred Johny Wüest, Directeur de thèse ; Damien Bouffard, Directeur de thèse Editeur : Lausanne : Ecole Polytechnique Fédérale de Lausanne EPFL Année de publication : 2018 Importance : 122 p. Format : 21 x 30 cm Note générale : bibliographie
Thèse présentée à l'Ecole Polytechnique Fédérale de Lausanne pour l'obtention du grade de Docteur ès SciencesLangues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] aide à la décision
[Termes IGN] calcaire
[Termes IGN] correction atmosphérique
[Termes IGN] décomposition empirique du signal
[Termes IGN] hydrodynamique
[Termes IGN] image Landsat-8
[Termes IGN] image Sentinel-MSI
[Termes IGN] image Terra-MODIS
[Termes IGN] Léman (Lac)
[Termes IGN] modèle dynamique
[Termes IGN] précipitation
[Termes IGN] réflectance
[Termes IGN] variation saisonnièreRésumé : (auteur) Freshwater resources play a central role in social and economic development of modern civilisations, yet their value is often underestimated and neglected in developed countries. In fact, freshwater habitats are facing unprecedented threat because of human activities, and it is necessary to provide reliable water quality indicators to monitor the response of aquatic systems. In this context, remote sensing has a great potential to provide a complementary source of data for monitoring and understanding the processes involved in inland waters around the world at fine temporal and spatial resolutions. The scientific approach adopted in this thesis is based on the integration of complementary sources of information provided by state-of-the-art monitoring methods to foster our understanding of freshwater habitats. Specifically, we demonstrate the additional value provided by combining complementary sensors with bio-geochemical measurements and hydrodynamic models, using a rare event in Lake Geneva which got a wide public attention in local newspapers: a calcite precipitation event. The principal focus of the remote-sensing community has recently been directed towards very turbid waters in order to address the challenges involved with the retrieval of mixed constituent concentrations. In this thesis, I highlight some important challenges relative to clearer waters which also require further attention from the community. Specifically, I provide a solution to account for vertical nonuniformities of water constituent concentrations using simple approximation models in Lake Geneva. Finally, I provide a comprehensive comparison between state-of-the-art atmospheric correction methods, which are presumably relevant for inland water monitoring and applicable to the new constellation of remote sensors. The aim is to provide reliable recommendations to help forthcoming studies to apply the most suited procedure to their investigation. Note de contenu : 1- Introduction
2- Resolving biogeochemical processes in lakes using remote sensing
3- Effects of non-uniform vertical constituent profiles on remote-sensing reflectance of oligo- to mesotrophic lakes
4- Inter-comparison of atmospheric corrections for S-2 observations over Lake Geneva
5- ConclusionNuméro de notice : 25790 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Thèse étrangère Note de thèse : Thèse de Doctorat : Sciences : EPFL : 2018 nature-HAL : Thèse En ligne : https://infoscience.epfl.ch/record/255664?ln=fr Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95007
Titre : Vehicle dynamic model based navigation for small UAVs Type de document : Thèse/HDR Auteurs : Mehran Khaghani, Auteur ; Jan Skaloud, Directeur de thèse Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 2018 Autre Editeur : Lausanne : Ecole Polytechnique Fédérale de Lausanne EPFL Collection : Geodätisch-Geophysikalische Arbeiten in der Schweiz, ISSN 0257-1722 num. 101 Importance : 138 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-908440-47-5 Note générale : bibliography
Thèse de Doctorat, EPFL, Lausanne, 2018Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] analyse de sensibilité
[Termes IGN] centrale inertielle
[Termes IGN] démonstration de faisabilité
[Termes IGN] drone
[Termes IGN] filtre de Kalman
[Termes IGN] GPS-INS
[Termes IGN] méthode de Monte-Carlo
[Termes IGN] modèle de simulation
[Termes IGN] modèle dynamique
[Termes IGN] navigation autonome
[Termes IGN] positionnement par GNSS
[Termes IGN] processus stochastique
[Termes IGN] ventIndex. décimale : 30.70 Navigation et positionnement Résumé : (auteur) The dominant navigation system for small civilian UAVs today is based on integration of inertial navigation system (INS) and global navigation satellite system (GNSS). This strategy works well to navigate the UAV, as long as proper reception of GNSS signal is maintained. However, when GNSS outage occurs, the INS-based navigation solution drifts very quickly, considering the limited quality of IMU(s) employed in INS for small UAVs. In beyond visual line of sight (BVLOS) flights, this poses the serious danger of losing the UAV and its eventual falling down. Limited payload capacity and cost for small UAVs, as well as the need for operating in different conditions, with limited visibility for example, make it challenging to find a solution to reach higher levels of navigation autonomy based on conventional approaches. This thesis aims to improve the accuracy of autonomous navigation for small UAVs by at least one order of magnitude. The proposed novel approach employs vehicle dynamic model (VDM) as process model within navigation system, and treats data from other sensors such as IMU, barometric altimeter, and GNSS receiver, whenever available, as observations within the system. Such improvement comes with extra effort required to determine the VDM parameters for any specific UAV. This work investigates the internal capability of the proposed system for estimating VDM parameters as part of the augmented state vector within an extended Kalman filter (EKF) as the estimator. This reduces the efforts required to setup such navigation system that is platform dependent. Multiple experimental flights using two custom made fixed-wing UAVs are presented together with Monte-Carlo simulations. The results reveal improvements of 1 to 2 orders of magnitude in navigation accuracy during GNSS outages of a few minutes' duration. Computational cost for the proposed VDM-based navigation does not exceed 3~times that of conventional INS-based systems, which establishes its applicability for online application. A global sensitivity analysis is presented, spotting the VDM parameters with higher influence on navigation performance. This provides insight for design of calibration procedures. The proposed VDM-based navigation system can be interesting for professional UAVs from at least two points of view. Firstly, it adds little to no extra hardware and cost to the UAV. Secondly and more importantly, it might be currently the only way to reach such significant improvement in navigation autonomy for small UAVs regardless of visibility conditions and electromagnetic signals reception. Possibly, such environmental condition independence for navigation system may be needed to obtain certifications from legal authorities to expand UAV applications to new types of mission. Note de contenu : 1- Preliminaries
2- VDM-based navigation framework
3- Results and analyses
4- Conclusion remarksNuméro de notice : 21988 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Note de thèse : Thèse Doctorat : : EPFL : 2018 nature-HAL : Thèse DOI : 10.5075/epfl-thesis-8494 En ligne : https://www.sgc.ethz.ch/publications.html Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91986 Réservation
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