A review of the use of optimal transport distances for high resolution seismic imaging based on the full waveform

We consider the high-resolution seismic imaging method called full-waveform inversion (FWI). FWI is a data fitting method aimed at inverting for subsurface mechanical parameters. Despite the large adoption of FWI by the academic and industrial communities, and many successful results, FWI still suffers from severe limitations. From a mathematical standpoint, FWI is a large scale PDE-constrained optimization problem. The misfit function that is used, which measures the discrepancy between observed seismic data and data calculated through the solution of a wave propagation problem, is non-convex. After discretization, the size of the FWI problem requires the use of local optimization solvers, which are prone to converge towards local minima. Thus the success of FWI strongly depends on the choice of the initial model to ensure the convergence towards the global minimum of the misfit function. This limitation has been the motivation for a large variety of strategies. Among the different methods that have been investigated, the use of optimal transport (OT) distances-based misfit functions has been recently promoted. The leading idea is to benefit from the inherent convexity of OT distances with respect to dilation and translation to render the FWI problem more convex. However, the application of OT distances in the framework of FWI is not straightforward, as seismic data is signed, while OT has been developed for the comparison of probability measures. The purpose of this study is to review two methods that were developed to overcome this difficulty. Both have been successfully applied to field data in an industrial framework. Both make it possible to better exploit the seismic data, alleviating the sensitivity to the initial model and to various conventional workflow steps, and reducing the uncertainty attached to the subsurface mechanical parameters inversion.Comment: 18 figure

SPICE+: EVALUATION OF AUTOMATIC AUDIO CAPTIONING SYSTEMS WITH PRE-TRAINED LANGUAGE MODELS

Audio captioning aims at describing acoustic scenes with natural language. Systems are currently evaluated by image cap-tioning metrics CIDEr and SPICE. However, recent studies have highlighted a poor correlation of these metrics with human assessments. In this paper, we propose SPICE+, a modification of SPICE that improves caption annotation and comparison with pre-trained language models. The metric parses captions to semantic graphs with a deep dependency annotation model and a refined set of linguistic rules, then compares sentence embeddings of candidate and reference semantic elements. We formulate a score for general-purpose captioning evaluation, that can be tailored to more specific applications. Combined with fluency error detection, the metric achieves competitive performance on the FENSE benchmark, with 84.0% accuracy on AudioCaps and 74.1% on Clotho.Further experiments show that the metric behaves similarly to the full sentence embedding similarity, while the decomposition into semantic elements allows better interpretability of scores and can provide additional information on the properties of captioning systems

Automated audio captioning by fine-tuning bart with audioset tags

International audienceAutomated audio captioning is the multimodal task of describing environmental audio recordings with fluent natural language. Most current methods utilize pre-trained analysis models to extract relevant semantic content from the audio input. However, prior information on language modeling is rarely introduced, and corresponding architectures are limited in capacity due to data scarcity. In this paper, we present a method leveraging the linguistic information contained in BART, a large-scale conditional language model with general purpose pre-training. The caption generation is conditioned on sequences of textual AudioSet tags. This input is enriched with temporally aligned audio embeddings that allows the model to improve the sound event recognition. The full BART architecture is fine-tuned with few additional parameters. Experimental results demonstrate that, beyond the scaling properties of the architecture, language-only pre-training improves the text quality in the multimodal setting of audio captioning. The best model achieves stateof-the-art performance on AudioCaps with 46.5 SPIDEr

Médamoud (2022)

Données scientifiques produites :https://www.ifao.egnet.net/recherche/archeologie/medamoud/ Introduction Sous les auspices de l’Ifao, de Sorbonne Université (UMR 8167 Orient & Méditerranée) et de la commission des fouilles du MEAE, la mission française de Médamoud (MFM) s’est déroulée du 7 février au 6 mars 2022. Une partie de l’équipe n’a pas pu se déplacer en Égypte en raison de la crise sanitaire mais a poursuivi ses travaux en France, essentiellement pour préparer l’édition de deux ouvrag..

Médamoud

Depuis 2011, la mission archéologique de Médamoud (Med) a repris la recherche sur le terrain suivant trois objectifs complémentaires : tout d’abord, étudier les secteurs inexplorés du kôm entourant le temple pour comprendre son environnement urbain, économique et social ; ensuite réexaminer la documentation issue des fouilles du début du xxe siècle dont les résultats doivent être précisés et actualisés ; et enfin assurer la mise en valeur du site. Fig. 1. Plan topographique du site (M. Gaber)..

Conferring a template-dependent polymerase activity to terminal deoxynucleotidyltransferase by mutations in the Loop1 region

Terminal deoxynucleotidyltransferase (Tdt) and DNA polymerase μ (pol μ) are two eukaryotic highly similar proteins involved in DNA processing and repair. Despite their high sequence identity, they differ widely in their activity: pol μ has a templated polymerase activity, whereas Tdt has a non-templated one. Loop1, first described when the Tdt structure was solved, has been invoked as the major structural determinant of this difference. Here we describe attempts to transform Tdt into pol μ with the minimal number of mutations in and around Loop1. First we describe the effect of mutations on six different positions chosen to destabilize Tdt Loop1 structure, either by alanine substitution or by deletion; they result at most in a reduction of Tdt activity, but adding Co++ restores most of this Tdt activity. However, a deletion of the entire Loop1 as in pol λ does confer a limited template-dependent polymerase behavior to Tdt while a chimera bearing an extended pol μ Loop1 reproduces pol μ behavior. Finally, 16 additional substitutions are reported, targeted at the two so-called ‘sequence determinant’ regions located just after Loop1 or underneath. Among them, the single-point mutant F401A displays a sequence-specific replicative polymerase phenotype that is stable upon Co++ addition. These results are discussed in light of the available crystal structures

Effect of terminal accuracy requirements on temporal gaze-hand coordination during fast discrete and reciprocal pointings

Background\ud \ud Rapid discrete goal-directed movements are characterized by a well known coordination pattern between the gaze and the hand displacements. The gaze always starts prior to the hand movement and reaches the target before hand velocity peak. Surprisingly, the effect of the target size on the temporal gaze-hand coordination has not been directly investigated. Moreover, goal-directed movements are often produced in a reciprocal rather than in a discrete manner. The objectives of this work were to assess the effect of the target size on temporal gaze-hand coordination during fast 1) discrete and 2) reciprocal pointings.\ud \ud Methods\ud \ud Subjects performed fast discrete (experiment 1) and reciprocal (experiment 2) pointings with an amplitude of 50 cm and four target diameters (7.6, 3.8, 1.9 and 0.95 cm) leading to indexes of difficulty (ID = log2[2A/D]) of 3.7, 4.7, 5.7 and 6.7 bits. Gaze and hand displacements were synchronously recorded. Temporal gaze-hand coordination parameters were compared between experiments (discrete and reciprocal pointings) and IDs using analyses of variance (ANOVAs).\ud \ud Results\ud \ud Data showed that the magnitude of the gaze-hand lead pattern was much higher for discrete than for reciprocal pointings. Moreover, while it was constant for discrete pointings, it decreased systematically with an increasing ID for reciprocal pointings because of the longer duration of gaze anchoring on target.\ud \ud Conclusion \ud \ud Overall, the temporal gaze-hand coordination analysis revealed that even for high IDs, fast reciprocal pointings could not be considered as a concatenation of discrete units. Moreover, our data clearly illustrate the smooth adaptation of temporal gaze-hand coordination to terminal accuracy requirements during fast reciprocal pointings. It will be interesting for further researches to investigate if the methodology used in the experiment 2 allows assessing the effect of sensori-motor deficits on gaze-hand coordination

Are we ready to track climate-driven shifts in marine species across international boundaries? - A global survey of scientific bottom trawl data

Marine biota are redistributing at a rapid pace in response to climate change and shifting seascapes. While changes in fish populations and community structure threaten the sustainability of fisheries, our capacity to adapt by tracking and projecting marine species remains a challenge due to data discontinuities in biological observations, lack of data availability, and mismatch between data and real species distributions. To assess the extent of this challenge, we review the global status and accessibility of ongoing scientific bottom trawl surveys. In total, we gathered metadata for 283,925 samples from 95 surveys conducted regularly from 2001 to 2019. We identified that 59% of the metadata collected are not publicly available, highlighting that the availability of data is the most important challenge to assess species redistributions under global climate change. Given that the primary purpose of surveys is to provide independent data to inform stock assessment of commercially important populations, we further highlight that single surveys do not cover the full range of the main commercial demersal fish species. An average of 18 surveys is needed to cover at least 50% of species ranges, demonstrating the importance of combining multiple surveys to evaluate species range shifts. We assess the potential for combining surveys to track transboundary species redistributions and show that differences in sampling schemes and inconsistency in sampling can be overcome with spatio-temporal modeling to follow species density redistributions. In light of our global assessment, we establish a framework for improving the management and conservation of transboundary and migrating marine demersal species. We provide directions to improve data availability and encourage countries to share survey data, to assess species vulnerabilities, and to support management adaptation in a time of climate-driven ocean changes.En prensa6,86