Sunyaev-Zel'dovich clusters reconstruction in multiband bolometer camera surveys

We present a new method for the reconstruction of Sunyaev-Zel'dovich (SZ) galaxy clusters in future SZ-survey experiments using multiband bolometer cameras such as Olimpo, APEX, or Planck. Our goal is to optimise SZ-Cluster extraction from our observed noisy maps. We wish to emphasize that none of the algorithms used in the detection chain is tuned on prior knowledge on the SZ -Cluster signal, or other astrophysical sources (Optical Spectrum, Noise Covariance Matrix, or covariance of SZ Cluster wavelet coefficients). First, a blind separation of the different astrophysical components which contribute to the observations is conducted using an Independent Component Analysis (ICA) method. Then, a recent non linear filtering technique in the wavelet domain, based on multiscale entropy and the False Discovery Rate (FDR) method, is used to detect and reconstruct the galaxy clusters. Finally, we use the Source Extractor software to identify the detected clusters. The proposed method was applied on realistic simulations of observations. As for global detection efficiency, this new method is impressive as it provides comparable results to Pierpaoli et al. method being however a blind algorithm. Preprint with full resolution figures is available at the URL: w10-dapnia.saclay.cea.fr/Phocea/Vie_des_labos/Ast/ast_visu.php?id_ast=728Comment: Submitted to A&A. 32 Pages, text onl

Two approaches for the simultaneous separation and deblurring ; application to astrophysical data

Two approaches are presented to solve the problem of simultaneously deconvolving and separating mixtures of components. The first one uses a statistical description of the wavelet coefficients of the signals. The second one consists in minimizing a variational functional. Both methods are applied to the reconstruction of Sunyaev-Zel’dovich galaxy clusters from Cosmic Microwave Background experiments such as ACT. We find that both methods, when tuned, yield similar results and that the reconstruction of intense clusters is substantially improved when their non-gaussianity is taken into account.Nous présentons deux approches pour résoudre le problème de séparation et de déconvolution simultanées de mélanges de composantes. La première est basée sur une description statistique des coefficients d’ondelettes des signaux. La seconde consiste à minimiser une fonctionnelle variationnelle. Nous appliquons ces deux méthodes à la reconstruction des amas de galaxies par l’effet Sunyaev-Zel’dovich dans le cadre de la mission d’observation du fond diffus cosmique par ACT. Nous trouvons que pour des paramètres appropriés, les deux méthodes donnent des résultats comparables et que prendre en compte le caractère nongaussien des amas très intenses améliore nettement leur reconstruction

Deux méthodes de déconvolution de mélanges de composantes; application à la reconstruction des amas de galaxies

Nous présentons deux approches pour résoudre le problème de séparation et de déconvolution simultané de mélanges de composantes. La première est basée sur une description statistique des coefficients d'ondelettes des signaux. La seconde est nouvelle et consiste à minimiser une fonctionnelle variationnelle. Nous appliquons ces deux méthodes à la reconstruction des amas de galaxies par l'effet Sunyaev-Zeldovich dans le cadre de la mission d'observation du fond diffus cosmique ACT. Nous trouvons que pour des paramètres appropriés, les deux méthodes donnent des résultats comparables et que prendre en compte le caractère non-gaussien des amas très intenses améliore nettement leur reconstruction

Dynamic behaviour analysis of an english-bond masonry prototype using a homogenized-based discrete FE model

Full Finite Element strategies (the so called micro- and macro- models) are still nowadays the most used ones for the study of large masonry structures. However, macro-modelling still lacks accuracy at a meso-scale in terms of damage localization. On the other hand, micro-models are rather computational demanding and require a cumbersome modelling stage. Thus, homogenization-based frameworks give considerable advantages. Moreover, the study of English bond masonry appears to be disregarded in comparison to the running bond one. On this behalf, a two-step procedure based on homogenization theory is herein presented for the dynamic study of English-bond masonry structures. The presented homogenization approach uses two models at a micro-scale: (i) a plane-stress FE discretization within the concepts of Kirchhoff-Love plate theory; and (ii) a three-dimensional micro-model accounting with the mortar joint discontinuity existent at the thickness direction. Bricks are meshed with elastic elements with linear interpolation and joints are reduced to interfaces which obey to the nonlinear behaviour described by the so-called combined cracking-shearing-crushing model. The procedure allows obtaining homogenized bending moment/torque curvature relationships to be used at a structural level within a FE discrete model implemented in a commercial code. The model relies in rigid quadrilateral elements interconnected by homogenized bending/torque nonlinear springs. The framework is used to study the dynamic behaviour of an English-bond masonry wall benchmark. A macroscopic strategy is also considered to enrich the study. The numerical results are compared with the experimental data and a good agreement has been found.FCT (Portuguese Foundation for Science and Technology), within ISISE, scholarship SFRH/BD/95086/2013. This work was also partly financed by FEDER funds through the Competitivity Factors Operational Programme - COMPETE and by national funds through FCT – Foundation for Science and Technology within the scope of the project POCI-01-0145-FEDER-00763

Proceedings of the second "international Traveling Workshop on Interactions between Sparse models and Technology" (iTWIST'14)

The implicit objective of the biennial "international - Traveling Workshop on Interactions between Sparse models and Technology" (iTWIST) is to foster collaboration between international scientific teams by disseminating ideas through both specific oral/poster presentations and free discussions. For its second edition, the iTWIST workshop took place in the medieval and picturesque town of Namur in Belgium, from Wednesday August 27th till Friday August 29th, 2014. The workshop was conveniently located in "The Arsenal" building within walking distance of both hotels and town center. iTWIST'14 has gathered about 70 international participants and has featured 9 invited talks, 10 oral presentations, and 14 posters on the following themes, all related to the theory, application and generalization of the "sparsity paradigm": Sparsity-driven data sensing and processing; Union of low dimensional subspaces; Beyond linear and convex inverse problem; Matrix/manifold/graph sensing/processing; Blind inverse problems and dictionary learning; Sparsity and computational neuroscience; Information theory, geometry and randomness; Complexity/accuracy tradeoffs in numerical methods; Sparsity? What's next?; Sparse machine learning and inference.Comment: 69 pages, 24 extended abstracts, iTWIST'14 website: http://sites.google.com/site/itwist1

Indirect structural health monitoring (iSHM) of transport infrastructure in the digital age

Workshop reportCopyright © Joint Research Centre (European Commission). The existing European motorway infrastructure network is prone to ageing and subject to natural events (e.g. climate change) and hazards (e.g. earthquakes), necessitating immediate actions for its maintenance and safety. Within this context, the structural health monitoring (SHM) framework allows a quantitative assessment of the structural integrity, serviceability and performance, facilitating better-informed decisions for the management of the existing infrastructure. The European Commission Joint Research Centre (JRC) established the exploratory research project MITICA (Monitoring Transport Infrastructures with Connected and Automated vehicles) to investigate the opportunity to use novel methods for infrastructure motoring, aiming at the efficient maintenance of the European aging road infrastructure. This report summarizes the discussion and the outcomes of a workshop held at the JRC in Ispra (Italy) on June 6-7 2022, as part of the MITICA project. Considering the EU priority “A Europe fit for the digital age”, the workshop was dedicated to SHM and its application to civil infrastructure, focusing on innovative indirect structural health monitoring (iSHM) approaches that rely on the vehicle-bridge interaction and the deployment of sensor-equipped vehicles for the monitoring of the existing bridge infrastructure. The report aims to become a reference document in the area of iSHM using passing vehicles, for both scholars and policy makers

Homogenization and seismic assessment : review and recent trends

The mechanics of masonry structures has been for long underdeveloped in comparison with other fields of knowledge. Presently, non-linear analysis is a popular field in masonry research and advanced computer codes are available for researchers and practitioners. The chapter presents a discussion of masonry behaviour and clarifies how to obtain the non-linear data required by the computations. The chapter also addresses different homogenisation techniques available in the literature in the linear and rigid-plastic case, aiming at defining a catalogue and at discussing the advantages and disadvantages of the different approaches. Special attention is given to stress assumed models based either on a polynomial expansion of the micro-stress field or in the discretization of the unit cell by means of a few constant stress finite elements CST with joints reduced to interfaces. Finally, the aspects of seismic assessment are presented and case studies involving the use of macro-block analysis, static (pushover) analysis and time integration analysis are discussed.(undefined

The Development and Validation of the Thai-Translated Irrational Performance Beliefs Inventory (T-iPBI)

© 2018, Springer Science+Business Media, LLC, part of Springer Nature. One of the most commonly employed cognitive-behavioural approaches to psychotherapy is rational-emotive behaviour therapy, but researchers have been troubled by some of the limitations of irrational beliefs psychometrics. As a result, Turner et al. (Eur J Psychol Assess 34:174–180, 2018a. https://doi.org/10.1027/1015-5759/a000314) developed the Irrational Performance Beliefs Inventory (iPBI), a novel measure of irrational beliefs for use within performance domains. However, the linguistic and cross-cultural adaptation of the iPBI into other languages is necessary for its multinational and multicultural use. The purpose of this paper is to develop the Thai-translated version of the iPBI (T-iPBI) and examine the validity and reliability of the T-iPBI. Data retrieved from 166 participants were analysed using SPSS and AMOS software packages. Thirty-three participants completed two follow-up T-iPBI measurements (1- and 3-week repeat assessment). After the linguistic and cross-cultural adaptation processes, the T-iPBI demonstrated excellent levels of reliability, with internal consistency and test–retest reliability, as well as construct, concurrent, and predictive validity. The current findings indicate that the 20-item T-iPBI can be used as a self-assessment instrument to evaluate individual’s irrational performance beliefs in a Thai population. We also highlight the implications of this study and suggest a variety of future research directions that stem from the results