207 research outputs found
Learnable Earth Parser pretrained weights
No full text<p>Pretrained weights to be used with the github <a href="http://github.com/romainloiseau/LearnableEarthParser">https://github.com/romainloiseau/LearnableEarthParser</a></p>
<p><strong>Cite as:</strong></p>
<blockquote>
<pre><span>@<span>article</span></span>{loiseau2024learnable,
title={Learnable Earth Parser: Discovering 3D Prototypes in Aerial Scans},
author={Romain Loiseau and Elliot Vincent and Mathieu Aubry and Loic Landrieu},
journal={CVPR},
year={2024}
}</pre>
</blockquote>
Correction de fronts d'onde de faisceaux lasers impulsionnels par mélange d'ondes photoréfractif.
No full textNous avons démontré que la correction de fronts d'onde de faisceaux lasers impulsionnels (nanoseconde) pouvait être réalisée par mélange d'ondes dans un cristal photoréfractif. Nous avons commence par déterminer le matériau photoréfractif le mieux adapte pour cette application. Pour des raisons d'efficacité photoréfractive et de tenue en puissance, notre choix s'est porte sur le titanate de baryum. Cela a conditionne le choix de la longueur d'onde utilisée (532 nm) pour cette démonstration. Nous avons étudié un premier dispositif de correction base sur le transfert d'énergie d'un faisceau fort vers un faisceau faible qui, par mélange d'ondes photoréfractif, peut être obtenu sans qu'il y ait de transfert de phase. Dans cette étude nous avons mesure les variations de l'amplification en fonction de différents paramètres (cohérence temporelle, rapport des énergies des faisceaux) et observe les variations de l'effet photorefractif en fonction de la densité de puissance dans le titanate de baryum. Nous avons aussi démontré la correction des déformations introduites par un objet de phase et cela pour différentes densités d'énergie incidente. Une deuxième méthode de correction est basée sur la compensation d'un aberrateur de phase par double passage. On a commence par préciser la notion de conjugaison de phase. Puis, nous avons étudié en particulier un miroir a conjugaison de phase auto pompe, l'oscillateur a boucle de réaction, qui fonctionne sur le principe du mélange a quatre ondes dans un cristal photoréfractif. Nous avons montre expérimentalement que des transformations des faisceaux dans la boucle de réaction améliorent la qualite de la conjugaison de phase et nous avons réalisé la compensation d'objets de phase par double passage en régime impulsionnel. La dernière partie est consacrée a l'étude comparative des deux dispositifs tels qu'ils pourront être mis en oeuvre pour la correction dynamique des lentilles thermiques dans les amplificateurs lasers solides
Companinon Dataset for PASTIS : VHR satellite images (SPOT 6-7)
No full text<p>To enhance the spatial resolution and utility of <a href="https://github.com/VSainteuf/pastis-benchmark">PASTIS-R dataset</a>, we introduce PASTIS-HD, which integrates contemporaneous VHR satellite images (SPOT 6-7), resampled to a 1m resolution and converted to 8 bits. This enhancement significantly improves the dataset's spatial content, providing more granular information for agricultural parcel segmentation.</p>
<p>This folder can be added to the PASTIS-R dataset to get the PASTIS-HD version.<br><br>The SPOT images are opendata thanks to the Dataterra Dinamis initiative in the case of the <a href="https://dinamis.data-terra.org/opendata/">"Couverture France DINAMIS" program</a>.<br><br></p>
<p>If you use PASTIS please cite the <a href="https://arxiv.org/abs/2107.07933" rel="nofollow">related paper</a>:</p>
<blockquote>
<p>@article{garnot2021panoptic,<br> title={Panoptic Segmentation of Satellite Image Time Series<br>with Convolutional Temporal Attention Networks},<br> author={Sainte Fare Garnot, Vivien and Landrieu, Loic },<br> journal={ICCV},<br> year={2021}<br>}</p>
</blockquote>
<p><br><br>For the PASTIS-R optical-radar fusion dataset, please also cite <a href="https://arxiv.org/abs/2112.07558v1" rel="nofollow">this paper</a>:</p>
<blockquote>
<pre>@article{garnot2021mmfusion,
title = {Multi-modal temporal attention models for crop mapping from satellite time series},
journal = {ISPRS Journal of Photogrammetry and Remote Sensing},
year = {2022},
doi = {https://doi.org/10.1016/j.isprsjprs.2022.03.012},
author = {Vivien {Sainte Fare Garnot} and Loic Landrieu and Nesrine Chehata},
}</pre>
</blockquote>
<p>For the PASTIS-HD with the 3 modality optical-radar time series plus VHR images dataset, please also cite <a href="https://arxiv.org/abs/2404.08351">this paper</a>:</p>
<blockquote>
<p>@article{astruc2024omnisat,<br> title={Omni{S}at: {S}elf-Supervised Modality Fusion for {E}arth Observation},<br> author={Astruc, Guillaume and Gonthier, Nicolas and Mallet, Clement and Landrieu, Loic},<br> journal={arXiv preprint arXiv:2404.08351},<br> year={2024}<br>}</p>
</blockquote>
Correction de fronts d'onde de faisceaux lasers impulsionnels par mélange d'ondes photoréfractif.
No full textNous avons démontré que la correction de fronts d'onde de faisceaux lasers impulsionnels (nanoseconde) pouvait être réalisée par mélange d'ondes dans un cristal photoréfractif. Nous avons commence par déterminer le matériau photoréfractif le mieux adapte pour cette application. Pour des raisons d'efficacité photoréfractive et de tenue en puissance, notre choix s'est porte sur le titanate de baryum. Cela a conditionne le choix de la longueur d'onde utilisée (532 nm) pour cette démonstration. Nous avons étudié un premier dispositif de correction base sur le transfert d'énergie d'un faisceau fort vers un faisceau faible qui, par mélange d'ondes photoréfractif, peut être obtenu sans qu'il y ait de transfert de phase. Dans cette étude nous avons mesure les variations de l'amplification en fonction de différents paramètres (cohérence temporelle, rapport des énergies des faisceaux) et observe les variations de l'effet photorefractif en fonction de la densité de puissance dans le titanate de baryum. Nous avons aussi démontré la correction des déformations introduites par un objet de phase et cela pour différentes densités d'énergie incidente. Une deuxième méthode de correction est basée sur la compensation d'un aberrateur de phase par double passage. On a commence par préciser la notion de conjugaison de phase. Puis, nous avons étudié en particulier un miroir a conjugaison de phase auto pompe, l'oscillateur a boucle de réaction, qui fonctionne sur le principe du mélange a quatre ondes dans un cristal photoréfractif. Nous avons montre expérimentalement que des transformations des faisceaux dans la boucle de réaction améliorent la qualite de la conjugaison de phase et nous avons réalisé la compensation d'objets de phase par double passage en régime impulsionnel. La dernière partie est consacrée a l'étude comparative des deux dispositifs tels qu'ils pourront être mis en oeuvre pour la correction dynamique des lentilles thermiques dans les amplificateurs lasers solides
Coping with the legacies of subsidized mortgage credit in Hungary
No full textThe authors examine alternatives for dealing with the initial conditions of housing finance facing countries making the transition to a market economy and moving toward a more efficient and equitable system. They focus on the problem of restructuring the stock of housing loans that exist at the time a new regime is implemented. Almost without exception, the stock of housing loans is yielding heavily subsidized rates, and its market value is significantly below its book value. Hungary makes an interesting case study. The mortgage portfolio inherited from past regimes makes especially clear the perverse implications of housing finance systems based on across-the-board subsidized interest rates. The authors propose a general approach to finding options to reduce the fiscal burden implicit in the subsidized housing loan portfolio. They identify mechanisms to reduce the interest subsidy embodied in that portfolio as well as mechanisms to spread the associated losses among those benefiting from the subsidies as well as among other parties. Clearly any residual subsidy must be absorbed by the government and ultimately by the population in the form of increased taxation or decreased availability of public services. The problem is complex and no obvious, easily implementable solutions emerge. But delaying action could hardly improve the situation.Banks&Banking Reform,Economic Theory&Research,Public Sector Economics&Finance,Housing Finance,Urban Economics
Financial structures and economic development
No full textThe author constructs a model that captures the two-way nature of the relationship between financial and economic development - and allows societies at different levels of economic development and with different policies to choose different financial services. In this model, various types of financial contracts and institutions arise in response to the economic environment. Incentives for financial structures to emerge are generated by liquidity and productivity risk, the costs of gathering information and mobilizing resources, and the costs of financial transactions. The emergence and development of financial arrangements in response to the economic environment can alter investment decisions and per capita growth rates - while the level of per capita income helps determine the types of financial services a particular society chooses to develop and use. The author not only reconciles more empirical regularities than past theoretical studies have done, but highlights the role of public policies on financial activities. Policy has important implications for the rate of economic growth, the level of financial development, and the types of institutions providing financial services. The model also predicts that per capita growth rates should be related to the types of financial services provided by the financial sector. Thus, the most common empirical measure of financial development may not appropriately capture fundamental features of financial development.Economic Theory&Research,Environmental Economics&Policies,Banks&Banking Reform,Financial Intermediation,Governance Indicators
Illicit economies and the carceral social zone
No full textThe author discusses the features of marginalised communities in European and Usa cities. Setting off with an analysis of Loic Wacquant's work on 'hyperghettoes', he delineates the illicit economies allowing such urban sites to survive and reproduce themselves. After noting that the conditions of such settings are not conducive to organised protest, he then defines the type of punishment to which their members are subjected. Rather than pure repression, the author sees some educational aspects in the disciplinary mechanism imposed on 'hyperghettoes'. Such aspects, he concludes, are meant to lower the expectation of those targeted and force them to adapt to marginalised and precarious social conditions
Advancement in screen printed fire through silver paste metallisation of polysilicon based passivating contacts
No full textWe have metallised n+ polysilicon passivated layer structures deposited by Low Pressure Chemical Vapor Deposition (LPCVD) with silver pastes. We analysed recombination at the metal contacts by photoluminescence imaging of metallised lifetime samples and found for the best paste, metal semiconductor recombination current density values (J0met) below 70 fA/cm2, with contact resistivity below 2 mΩcm2. To our knowledge, these are among the lowest values reported so far for full size M2 wafers with 150 nm thin polysilicon layer and wet chemical thin oxide. We also studied the effect of the peak firing temperature on the J0met and contact resistivity in this work. Further, we performed Scanning Electron Microscopy to further understand the silver polysilicon interface.Photovoltaic Materials and DevicesElectrical Sustainable Energ
The PV-Battery Integrated Module: Energy Storage Sizing
No full textThe physical integration of a battery system to the back of PV module provides solutions to the changing demands of the residential solar energy market. The PV-Battery Integrated Module (PBIM) concept is proposed and equips energy-users with a modular and user friendly solar system. With each PV panel equipped with its exclusive balance of system components, the PBIM aims to rival conventional solar home systems on an economic basis. With a potential to offer savings on the installation process and removing the need to customize every residential solar system the use of PBIM is a promising step towards the widespread implementation of solar systems.This project contributes towards the PBIM design by exploring the effects of energy storage motivations and ambient conditions on the optimal PBIM energy storage capabilities and the subsequent impact on its performance as whole. To quantify these impacts realistic case studies are developed and test the PBIM's capabilities in Costa Rica and the Netherlands. The PBIM, for each location, was assessed for its application in a grid-tied system for peak shaving applications and its performance as a stand-alone solution.\\As compared to conventional solar systems, the PBIM operates at higher temperatures, influencing the performance and lifetime of the incorporated components. This thesis commences by capturing the effects of elevated operating temperatures through the development of a PBIM model. The energy control strategy is devised to simulate the battery charging profiles for the identified applications. Location specific parameters are then implemented to asses the PBIM performance and the influence of different climates.A sizing methodology is used to derive the appropriate battery capacity for each case study. A comparison is made between the dynamic characteristics of the optimally sized system for each of the locations, indicating the fulfillment of the respective system objectives, minimizing battery degradation and maximizing autarky. Furthermore, the technical and economic feasibility of the PBIM concept is assessed with respect to a conventional solar home system, leading to the conclusion that the PBIM, at this point in time, possesses technical characteristics comparable to that of a convectional PV system. The PBIM concept is still in the early stages of development and there are still many challenges that need to be overcome before its widespread usage.Electrical Engineering | Sustainable Energy Technolog
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