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Mavromatidis L.E.,CNRS Computer Science and Engineering Laboratory
Energy and Buildings | Year: 2015

The present review paper focuses on the exploration and qualitative evaluation of hybrid optimization methods applied to architectural design, computational morphogenesis and energy consumption problems. After introducing the computational morphogenesis notion and the novel institutional framework of nZEB labeling, we define here computational morphogenesis as a design procedure where the environmental qualities of the envelope and especially thermal storage and load shifting have the potential to guide an automation process of shape creation in the building scale. For this reason we focus on reviewing the well-cited literature on scale that introduced novel hybrid optimization tools especially developed for thermal load, energy consumption optimization and/or computational morphogenesis optimization issues. Different approaches and methods are reported in this review paper, while at the end of the paper an exhaustive list of conclusions and potential perspectives of these approaches is explicitly presented. Inexorably, we seek to review here hybrid optimization tools that are (or could be) applied on computational morphogenesis problems with the aim to optimize, facilitate and encourage a creative architectural design in relation to innovative envelope conception to promote interdisciplinary research coupling the fields of architectural design and building physics. © 2015 Elsevier B.V.


Studholme C.,University of Washington | Rousseau F.,CNRS Computer Science and Engineering Laboratory
International Journal of Developmental Neuroscience | Year: 2014

Recent advances in medical imaging are beginning to allow us to quantify brain tissue maturation in the growing human brain prior to normal term age, and are beginning to shed new light on early human brain growth. These advances compliment the work already done in cellular level imaging in animal and post mortem studies of brain development. The opportunities for collaborative research that bridges the gap between macroscopic and microscopic windows on the developing brain are significant. The aim of this paper is to provide a review of the current research into MR imaging of the living fetal brain with the aim of motivating improved interfaces between the two fields. The review begins with a description of faster MRI techniques that are capable of freezing motion of the fetal head during the acquisition of a slice, and how these have been combined with advanced post-processing algorithms to build 3D images from motion scattered slices. Such rich data has motivated the development of techniques to automatically label developing tissue zones within MRI data allowing their quantification in 3D and 4D within the normally growing fetal brain. These methods have provided the basis for later work that has created the first maps of tissue growth rate and cortical folding in normally developing brains in-utero. These measurements provide valuable findings that compliment those derived from post-mortem anatomy, and additionally allow for the possibility of larger population studies of the influence of maternal environmental and genes on early brain development. © 2013 Published by Elsevier Ltd.


Gunzburger Y.,CNRS Georesources lab | Magnenet V.,CNRS Computer Science and Engineering Laboratory
Tectonophysics | Year: 2014

We investigate the source of non-purely gravitational horizontal stresses in the Paris basin, a nowadays tectonically quiet intracratonic basin, in its eastern border of which outstandingly dense stress measurements are available. Based on a synthesis of published data, the stress state in the basin is first shown to be very close to the one that may be extrapolated for the underlying basement, in terms of principal stress orientations and horizontal to vertical stress ratios. This is in favour of a mechanical coupling between the basement and its sedimentary cover, which may seem contradictory to the presence of several weak rock layers in the basin fill, e.g. an argillite layer that was shown to bear low deviatoric stresses, and salt layers that are implicated in a major décollement elsewhere. To unravel this apparent contradiction, a 3D-numerical modelling is performed, following a rigorous inverse problem approach, to determine the long-term elastic properties of both the basement and the basin rocks. The objective is to find the set of elastic constants that provides the best fit between the calculated stress state in the basin and the in situ data, by assuming that the stress state in the basement is known. This methodology provides a realistic set of mechanical parameters, in agreement with previous studies, which leads to the conclusion that the horizontal stresses in the basin constitute its mechanical response to the stresses that developed in the underlying basement during and since the last tectonic event (Alpine phase). The fact that horizontal stresses could be transmitted across the weak horizons, contrary to what may be expected at first glance, is explained both by the geometry of the basin and the fact that, over the long term, the stiffnesses of the various sedimentary rocks are only slightly different from each other. © 2014 Elsevier B.V.


Barbacci A.,French National Institute for Agricultural Research | Lahaye M.,French National Institute for Agricultural Research | Magnenet V.,CNRS Computer Science and Engineering Laboratory
PLoS ONE | Year: 2013

Expansive growth of plant cell is conditioned by the cell wall ability to extend irreversibly. This process is possible if (i) a tensile stress is developed in the cell wall due to the coupling effect between turgor pressure and the modulation of its mechanical properties through enzymatic and physicochemical reactions and if (ii) new cell wall elements can be synthesized and assembled to the existing wall. In other words, expansive growth is the result of coupling effects between mechanical, thermal and chemical energy. To have a better understanding of this process, models must describe the interplay between physical or mechanical variable with biological events. In this paper we propose a general unified and theoretical framework to model growth in function of energy forms and their coupling. This framework is based on irreversible thermodynamics. It is then applied to model growth of the internodal cell of Chara corallina modulated by changes in pressure and temperature. The results describe accurately cell growth in term of length increment but also in term of cell pectate biosynthesis and incorporation to the expanding wall. Moreover, the classical growth model based on Lockhart's equation such as the one proposed by Ortega, appears as a particular and restrictive case of the more general growth equation developed in this paper. © 2013 Barbacci et al.


Charpentier I.,CNRS Computer Science and Engineering Laboratory
Computer Physics Communications | Year: 2016

Considerable research efforts have been directed at implementing the Faddeeva function w(z) and its derivatives with respect to z, but these did not consider the key computing issue of a possible dependence of z on some variable t. The general case is to differentiate the compound function w(z(t))=w(ring operator)z(t) with respect to t by applying the chain rule for a first order derivative, or Faà di Bruno's formula for higher-order ones. Higher-order automatic differentiation (HOAD) is an efficient and accurate technique for derivative calculation along scientific computing codes. Although codes are available for w(z), a special symbolic HOAD is required to compute accurate higher-order derivatives for w(ring operator)z(t) in an efficient manner. A thorough evaluation is carried out considering a nontrivial case study in optics to support this assertion. Program summary: Program title: HOAD_MathFun. Catalogue identifier: AFAG_v1_0. Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AFAG_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland. Licensing provisions: yes. No. of lines in distributed program, including test data, etc.: 4737. No. of bytes in distributed program, including test data, etc.: 103450. Distribution format: tar.gz. Programming language: Fortran 90. Computer: Non-specific. Operating system: Non-specific. RAM: 1 megabyte. Classification: 4.12. External routines: Algorithm 680 [8], Mathematical functions (included). Nature of problem: General optimized higher-order automatic differentiation of mathematical functions. Complex refractive index as a case study. Solution method: Higher-order differentiation for the general second order ordinary equation defining the mathematical functions. Optimized operator overloading recurrence formula. Unusual features: Automatic differentiation, Quadratic complexity. Running time: 1 second. © 2016 Elsevier B.V.

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