Developing digital historians in Italy

Criminalising resistance, entrenching neoliberalism: the Fayyadist Paradigm in the occupied Palestinian West Bank

Tartir, Alaa (2015) Criminalising resistance, entrenching neoliberalism: the Fayyadist Paradigm in the occupied Palestinian West Bank. PhD thesis, The London School of Economics and Political Science (LSE).

from LSE Theses Online: No conditions. Results ordered -Date Deposited. http://ift.tt/1KLcBhJ

Representations of madness on British television: a social psychological analysis

Rose, Diana (1995) Representations of madness on British television: a social psychological analysis. PhD thesis, The London School of Economics and Political Science (LSE).

from LSE Theses Online: No conditions. Results ordered -Date Deposited. http://ift.tt/1L44k9N

Social networks and entrepreneurship: the British merchant community of Uruguay, 1830-1875

Sims, Peter (2014) Social networks and entrepreneurship: the British merchant community of Uruguay, 1830-1875. PhD thesis, The London School of Economics and Political Science (LSE).

from LSE Theses Online: No conditions. Results ordered -Date Deposited. http://ift.tt/1VmUW7Y

Saving the states’ face: an ethnography of the ASEAN secretariat and diplomatic field in Jakarta

Nair, Deepak (2015) Saving the states’ face: an ethnography of the ASEAN secretariat and diplomatic field in Jakarta. PhD thesis, The London School of Economics and Political Science (LSE).

from LSE Theses Online: No conditions. Results ordered -Date Deposited. http://ift.tt/1O1KCMZ

Global environmental change and international law: prospects for progress in the legal order

Jurgielewicz, Lynne (1995) Global environmental change and international law: prospects for progress in the legal order. PhD thesis, The London School of Economics and Political Science (LSE).

from LSE Theses Online: No conditions. Results ordered -Date Deposited. http://ift.tt/1OFItrP

The structure of theoretical systems in relation to emergence

Palmer, Kent (1982) The structure of theoretical systems in relation to emergence. PhD thesis, The London School of Economics and Political Science (LSE).

from LSE Theses Online: No conditions. Results ordered -Date Deposited. http://ift.tt/1P1O36U

Whittle estimation of multivariate exponential volatility models

Marchese, Malvina (2015) Whittle estimation of multivariate exponential volatility models. PhD thesis, The London School of Economics and Political Science (LSE).

from LSE Theses Online: No conditions. Results ordered -Date Deposited. http://ift.tt/1h33XA9

Temporary protection, technology adoption and economic development: data and evidence from the age of revolution in France

Juhász, Réka (2015) Temporary protection, technology adoption and economic development: data and evidence from the age of revolution in France. PhD thesis, The London School of Economics and Political Science (LSE).

from LSE Theses Online: No conditions. Results ordered -Date Deposited. http://ift.tt/1L0kOzR

The frontiers of state practice in Britain and France: pioneering high speed railway technology and infrastructure

Powell, Roxanne (1995) The frontiers of state practice in Britain and France: pioneering high speed railway technology and infrastructure. PhD thesis, The London School of Economics and Political Science (LSE).

from LSE Theses Online: No conditions. Results ordered -Date Deposited. http://ift.tt/1MUhyYQ

Risen from chaos: the development of modern education in China, 1905-1948

Gao, Pei (2015) Risen from chaos: the development of modern education in China, 1905-1948. PhD thesis, The London School of Economics and Political Science (LSE).

from LSE Theses Online: No conditions. Results ordered -Date Deposited. http://ift.tt/1MU1QNx

A liberalism without liberals

Argenton, Carlo (2015) A liberalism without liberals. PhD thesis, The London School of Economics and Political Science (LSE).

from LSE Theses Online: No conditions. Results ordered -Date Deposited. http://ift.tt/1MU1QNp

Interstate warfare and the emergence of transnational insurgencies

Ohlers, Curtis (2014) Interstate warfare and the emergence of transnational insurgencies. PhD thesis, The London School of Economics and Political Science (LSE).

from LSE Theses Online: No conditions. Results ordered -Date Deposited. http://ift.tt/1GbZm5g

Older adults, e-inclusion and access to ICT-based care

Damant, Jacqueline (2014) Older adults, e-inclusion and access to ICT-based care. PhD thesis, The London School of Economics and Political Science (LSE).

from LSE Theses Online: No conditions. Results ordered -Date Deposited. http://ift.tt/1VirkZv

Essays in international finance

Mallucci, Enrico (2014) Essays in international finance. PhD thesis, The London School of Economics and Political Science (LSE).

from LSE Theses Online: No conditions. Results ordered -Date Deposited. http://ift.tt/1GbHsQ7

Designing a Context-Sensitive Context Detection Service for Mobile Devices

Designing a Context-Sensitive Context Detection Service for Mobile Devices Chen, Tiffany Yu-Han; Sivaraman, Anirudh; Das, Somak; Ravindranath, Lenin; Balakrishnan, Hari This paper describes the design, implementation, and evaluation of Amoeba, a context-sensitive context detection service for mobile devices. Amoeba exports an API that allows a client to express interest in one or more context types (activity, indoor/outdoor, and entry/exit to/from named regions), subscribe to specific modes within each context (e.g., "walking" or "running", but no other activity), and specify a response latency (i.e., how often the client is notified). Each context has a detector that returns its estimate of the mode. The detectors take both the desired subscriptions and the current context detection into account, adjusting both the types of sensors and the sampling rates to achieve high accuracy and low energy consumption. We have implemented Amoeba on Android. Experiments with Amoeba on 45+ hours of data show that our activity detector achieves an accuracy between 92% and 99%, outperforming previous proposals like UCLA* (59%), EEMSS (82%) and SociableSense (72%), while consuming 4 to 6× less energy.

from Computer Science and Artificial Intelligence Lab (CSAIL) http://ift.tt/1Leov76

Signe et expression dans les réécritures des recherches logiques de Husserl

par Lydia AZI Université de Lille 3 2014

from Memoire Online http://ift.tt/1NiT8q3

Network Maximal Correlation

Network Maximal Correlation Feizi, Soheil; Makhdoumi, Ali; Duffy, Ken; Kellis, Manolis; Medard, Muriel Identifying nonlinear relationships in large datasets is a daunting task particularly when the form of the nonlinearity is unknown. Here, we introduce Network Maximal Correlation (NMC) as a fundamental measure to capture nonlinear associations in networks without the knowledge of underlying nonlinearity shapes. NMC infers, possibly nonlinear, transformations of variables with zero means and unit variances by maximizing total nonlinear correlation over the underlying network. For the case of having two variables, NMC is equivalent to the standard Maximal Correlation. We characterize a solution of the NMC optimization using geometric properties of Hilbert spaces for both discrete and jointly Gaussian variables. For discrete random variables, we show that the NMC optimization is an instance of the Maximum Correlation Problem and provide necessary conditions for its global optimal solution. Moreover, we propose an efficient algorithm based on Alternating Conditional Expectation (ACE) which converges to a local NMC optimum. For this algorithm, we provide guidelines for choosing appropriate starting points to jump out of local maximizers. We also propose a distributed algorithm to compute a 1-$\epsilon$ approximation of the NMC value for large and dense graphs using graph partitioning. For jointly Gaussian variables, under some conditions, we show that the NMC optimization can be simplified to a Max-Cut problem, where we provide conditions under which an NMC solution can be computed exactly. Under some general conditions, we show that NMC can infer the underlying graphical model for functions of latent jointly Gaussian variables. These functions are unknown, bijective, and can be nonlinear. This result broadens the family of continuous distributions whose graphical models can be characterized efficiently. We illustrate the robustness of NMC in real world applications by showing its continuity with respect to small perturbations of joint distributions. We also show that sample NMC (NMC computed using empirical distributions) converges exponentially fast to the true NMC value. Finally, we apply NMC to different cancer datasets including breast, kidney and liver cancers, and show that NMC infers gene modules that are significantly associated with survival times of individuals while they are not detected using linear association measures.

from Computer Science and Artificial Intelligence Lab (CSAIL) http://ift.tt/1FxrRPV

Assessment of community health workers incentives on maternal and newborn health services performance

par Denys NDANGURURA Bugeman University Uganda 2015

from Memoire Online http://ift.tt/1NiT8q3

Einsatz von HemOral® zur Kontrolle der Eisenmangelanämie beim Saugferkel

Ripke, Sandra (2015): Einsatz von HemOral® zur Kontrolle der Eisenmangelanämie beim Saugferkel. Dissertation, LMU München: Tierärztliche Fakultät

from Elektronische Dissertationen der LMU München: http://ift.tt/1iNyuE6

Auswirkungen der Aufgabenschwierigkeit auf altersabhängige Aktivierungsmuster in einer Arbeitsgedächtnisaufgabe

Fink, Thomas (2015): Auswirkungen der Aufgabenschwierigkeit auf altersabhängige Aktivierungsmuster in einer Arbeitsgedächtnisaufgabe. Dissertation, LMU München: Fakultät für Psychologie und Pädagogik

from Elektronische Dissertationen der LMU München: http://ift.tt/1MrpVs4

Untersuchungen zu spezifischen hippokampalen Läsionsmustern bei epileptischen Katzen

Wagner, Eva Katharina (2015): Untersuchungen zu spezifischen hippokampalen Läsionsmustern bei epileptischen Katzen. Dissertation, LMU München: Tierärztliche Fakultät

from Elektronische Dissertationen der LMU München: http://ift.tt/1MKs2dk

Organic and Hybrid Materials for Photonics and Electronics

Organic and Hybrid Materials for Photonics and Electronics Perry, Joseph In this talk, I will present an overview of my group’s research on materials for photonics and electronics. Polymethine dyes are promising materials for nonlinear optical processes such as all-optical signal processing (AOSP) but efforts to utilize these dyes at high concentrations has been impeded by aggregation that has deleterious effects on the optical nonlinearity and optical absorption loss. We are researching strategies to block polymethines from aggregating by substitution with rigid, bulky groups that project out of the plane polymethine. This approach has lead to high-number-density films with macroscopic nonlinear optical properties and high two-photon figures of merit close to those needed for AOSP. The polymethines developed also exhibit a negative Re| [superscript X(3)]| that is useful in the compensation of spectral broadening in optical fibers. Dielectric materials with high energy density and efficiency are critical for energy storage applications. Charge injection into the dielectric is undesirable as it leads to poor energy extraction efficiency. We have developed silica-organic hybrid sol-gel materials that exhibit high dielectric constant and breakdown strength through improvements in processing and the incorporation of nanoscale charge-blocking layers. Nanoscale charge blocking layers with layer thickness in the range of 100 nm to ~1 nm deposited between have been the dielectric film and the metal (Al) electrodes have led to large improvements in energy density and extraction efficiency. I will highlight our materials research efforts including: processing methods for sol-gel dielectrics, characterization of bilayer capacitors consisting of sol-gel and charge blocking layers. Our investigations provide insights into the development of high-performance dielectric materials/devices from organic/inorganic hybrid materials.; Joseph W. Perry received his B.S in Chemistry at the University of South Florida and his Ph.D. at Caltech. He has been a Professor of Chemistry in the School of Chemistry and Biochemistry at the Georgia Institute of Technology for 12 years. His research interests include electronic materials for energy storage including sol-gel based dielectrics with high energy/power density, nonlinear properties of conjugated molecules and polymers in nanophotonic structures for all-optical signal processing, and use of two-photon absorption processes for 3D micro- and nano- fabrication. Dr. Perry has received several awards and is a Fellow of OSA, APS, and AAAS. He has published over 240 scientific papers, and is an inventor on 13 issued patents. Presented on September 22, 2015 at 12 noon in the Pettit Microelectronics Building Conference Room 102 A&B, Georgia Tech.; Runtime: 57:21 minutes

from Theses online http://www.rssmix.com/

Stellenwert epidemiologischer, klinischer und labordiagnostischer Parameter bei der Diagnose importierter Helminthiasen

Perona, Pamela (2015): Stellenwert epidemiologischer, klinischer und labordiagnostischer Parameter bei der Diagnose importierter Helminthiasen. Dissertation, LMU München: Medizinische Fakultät

from Elektronische Dissertationen der LMU München: http://ift.tt/1V9TfW2

Evaluation der humanen Natrium-Jodid-Symporter-Aktivität mittels 124I-PET-Reportergenbildgebung zur hochsensitiven Überwachung der Teratombildung im Mausmodell

Kaissis, Georgios (2015): Evaluation der humanen Natrium-Jodid-Symporter-Aktivität mittels 124I-PET-Reportergenbildgebung zur hochsensitiven Überwachung der Teratombildung im Mausmodell. Dissertation, LMU München: Medizinische Fakultät

from Elektronische Dissertationen der LMU München: http://ift.tt/1Ftouth

Möglichkeiten, Limitationen, Komplikationen transbrachialer Zugänge für periphere endovaskuläre Interventionen

König, Cosima Teresa (2015): Möglichkeiten, Limitationen, Komplikationen transbrachialer Zugänge für periphere endovaskuläre Interventionen: ein Vergleich zu inguinalen Standard-Zugängen. Dissertation, LMU München: Medizinische Fakultät

from Elektronische Dissertationen der LMU München: http://ift.tt/1FtoucV

Reliabilitätsprüfung und Differenzierung von ereigniskorrelierten Potentialen in Zusammenhang mit Entscheidungs- und Verhaltenskontrollprozessen

Loy, Fabian (2015): Reliabilitätsprüfung und Differenzierung von ereigniskorrelierten Potentialen in Zusammenhang mit Entscheidungs- und Verhaltenskontrollprozessen. Dissertation, LMU München: Medizinische Fakultät

from Elektronische Dissertationen der LMU München: http://ift.tt/1FtorxB

Retrospektive Studie zur Therapie, Rezidiv- und Primärheilungsrate des Sinus pilonidalis unter besonderer Berücksichtigung des Pit picking Verfahrens

Choplain, Cornelia (2015): Retrospektive Studie zur Therapie, Rezidiv- und Primärheilungsrate des Sinus pilonidalis unter besonderer Berücksichtigung des Pit picking Verfahrens. Dissertation, LMU München: Medizinische Fakultät

from Elektronische Dissertationen der LMU München: http://ift.tt/1V9TfFH

Inklusion und Kognition

Watarai, Tomoko (2015): Inklusion und Kognition: eine systemtheoretische Betrachtung der Praxis aktivierender Integrationspolitik. Dissertation, LMU München: Sozialwissenschaftliche Fakultät

from Elektronische Dissertationen der LMU München: http://ift.tt/1MIc2IZ

Nanoporous metal oxides templated by nanocrystalline cellulose

Ivanova, Alesja (2015): Nanoporous metal oxides templated by nanocrystalline cellulose: synthesis and applications in photovoltaics and photocatalysis. Dissertation, LMU München: Fakultät für Chemie und Pharmazie

from Elektronische Dissertationen der LMU München: http://ift.tt/1NLwsPG

In vitro Effekte von Interferon alpha und Chemotherapeutika auf das B7-H1 Molekül im Pankreasadenokarzinom

Fritz, Jasmin (2015): In vitro Effekte von Interferon alpha und Chemotherapeutika auf das B7-H1 Molekül im Pankreasadenokarzinom. Dissertation, LMU München: Tierärztliche Fakultät

from Elektronische Dissertationen der LMU München: http://ift.tt/1gMkfNI

How can we know what is "moral"?

Kaufmann, David (2015): How can we know what is "moral"?: philosophical commitments in empirical research on moral judgment. Dissertation, LMU München: Graduate School of Systemic Neurosciences (GSN)

from Elektronische Dissertationen der LMU München: http://ift.tt/1NLwszq

Statistical theory of the atom in momentum space

Conta, Verena von (2015): Statistical theory of the atom in momentum space. Dissertation, LMU München: Fakultät für Mathematik, Informatik und Statistik

from Elektronische Dissertationen der LMU München: http://ift.tt/1gMkcSc

Photogeneration of reactive intermediates

Thallmair, Sebastian (2015): Photogeneration of reactive intermediates: From initial quantum dynamics to chemical yields in solution. Dissertation, LMU München: Fakultät für Chemie und Pharmazie

from Elektronische Dissertationen der LMU München: http://ift.tt/1JoJtsk

Spatially-resolved star formation histories and molecular gas depletion time of nearby galaxies

Huang, Mei-Ling (2015): Spatially-resolved star formation histories and molecular gas depletion time of nearby galaxies. Dissertation, LMU München: Fakultät für Physik

from Elektronische Dissertationen der LMU München: http://ift.tt/1NLvqDn

Structure of the Bacillus subtilis 70S ribosome reveals the basis for species-specific stalling

Sohmen, Daniel (2015): Structure of the Bacillus subtilis 70S ribosome reveals the basis for species-specific stalling. Dissertation, LMU München: Fakultät für Chemie und Pharmazie

from Elektronische Dissertationen der LMU München: http://ift.tt/1JoJtbU

Charakterisierung interindividueller Strahlenempfindlichkeit in Zellen aus Tumorpatienten

Dietz, Anne (2015): Charakterisierung interindividueller Strahlenempfindlichkeit in Zellen aus Tumorpatienten. Dissertation, LMU München: Fakultät für Biologie

from Elektronische Dissertationen der LMU München: http://ift.tt/1OQEZBX

Adenoviruses in Côte d`Ivoire: investigation of diversity and interspecies transmission

Pauly, Maude (2015): Adenoviruses in Côte d`Ivoire: investigation of diversity and interspecies transmission. Dissertation, LMU München: Tierärztliche Fakultät

from Elektronische Dissertationen der LMU München: http://ift.tt/1WfKNXG

Dynamic response of individual cells in heterogeneous population

Sekhavati, Farzad (2015): Dynamic response of individual cells in heterogeneous population. Dissertation, LMU München: Fakultät für Physik

from Elektronische Dissertationen der LMU München: http://ift.tt/1Fd0afs

Structural characterization of the Swi2/Snf2 ATPase Mot1 in complex with protein and DNA substrate

Butryn, Agata Anna (2015): Structural characterization of the Swi2/Snf2 ATPase Mot1 in complex with protein and DNA substrate. Dissertation, LMU München: Fakultät für Chemie und Pharmazie

from Elektronische Dissertationen der LMU München: http://ift.tt/1WfKNHl

Classification and functional characterization of extracytoplasmic function (ECF) σ factors from planctomycetes and actinobacteria

Huang, Xiaoluo (2015): Classification and functional characterization of extracytoplasmic function (ECF) σ factors from planctomycetes and actinobacteria. Dissertation, LMU München: Fakultät für Physik

from Elektronische Dissertationen der LMU München: http://ift.tt/1WfKNHe

Akustische Analysen der Sprachproduktion von CI-Trägern

Neumeyer, Veronika (2015): Akustische Analysen der Sprachproduktion von CI-Trägern. Dissertation, LMU München: Fakultät für Sprach- und Literaturwissenschaften

from Elektronische Dissertationen der LMU München: http://ift.tt/1WfKNqL

Formulation of PEGylated and HESylated biopharmaceuticals

Liebner, Robert (2015): Formulation of PEGylated and HESylated biopharmaceuticals. Dissertation, LMU München: Fakultät für Chemie und Pharmazie

from Elektronische Dissertationen der LMU München: http://ift.tt/1FrrIgM

Calcium Iron Palladium Arsenides and related compounds

Stürzer, Christine (2015): Calcium Iron Palladium Arsenides and related compounds. Dissertation, LMU München: Fakultät für Chemie und Pharmazie

from Elektronische Dissertationen der LMU München: http://ift.tt/1V85N0h

Einfluss einer kohlenhydratarmen Fütterung auf den Stickstoff-Stoffwechsel und die Kalziumverfügbarkeit bei Ratten

Frommelt, Lena (2015): Einfluss einer kohlenhydratarmen Fütterung auf den Stickstoff-Stoffwechsel und die Kalziumverfügbarkeit bei Ratten. Dissertation, LMU München: Tierärztliche Fakultät

from Elektronische Dissertationen der LMU München: http://ift.tt/1FrrI0k

Antikörper als neue Faktoren im immunologischen Prozess der venösen Thrombose, Antibodies as new factors in the immunological process of venous thrombosis

Busse, Johanna (2015): Antikörper als neue Faktoren im immunologischen Prozess der venösen Thrombose, Antibodies as new factors in the immunological process of venous thrombosis. Dissertation, LMU München: Tierärztliche Fakultät

from Elektronische Dissertationen der LMU München: http://ift.tt/1FrrJBs

Interaktionen Monozyten/ Makrophagen, neutrophilen Granulozyten und Thrombozyten bei steriler Inflammation im Gewebe, Tissue interactions between monocytes/ macrophages, neutrophils and platelets in the background of sterile inflammation

Miller, Meike Elisabeth (2015): Interaktionen Monozyten/ Makrophagen, neutrophilen Granulozyten und Thrombozyten bei steriler Inflammation im Gewebe, Tissue interactions between monocytes/ macrophages, neutrophils and platelets in the background of sterile inflammation. Dissertation, LMU München: Tierärztliche Fakultät

from Elektronische Dissertationen der LMU München: http://ift.tt/1V85MJJ

Afrikanische Schweinepest

Pietschmann, Jana (2015): Afrikanische Schweinepest: Charakterisierung aktueller Isolate sowie Entwicklung und Testung praxistauglicher Überwachungsoptionen. Dissertation, LMU München: Tierärztliche Fakultät

from Elektronische Dissertationen der LMU München: http://ift.tt/1KsR3Gp

Ultrastrukturelle und histochemische Untersuchungen am Blut der Ziege

Weißmüller, Alfons (2015): Ultrastrukturelle und histochemische Untersuchungen am Blut der Ziege. Dissertation, LMU München: Tierärztliche Fakultät

from Elektronische Dissertationen der LMU München: http://ift.tt/1OO2jAl

Auswirkung präanalytischer Einflussgrößen auf die Konzentrationen ausgewählter Stoffwechselhormone - sowie Einfluss von Alter und Fastendauer auf spezifische Stoffwechselhormone bei der Ratte, Impact of preanalytical factors on the concentration of specific metabolic hormones and effect of age and fasting on specific metabolic hormones in rats

Popp, Sarah-Teresa (2015): Auswirkung präanalytischer Einflussgrößen auf die Konzentrationen ausgewählter Stoffwechselhormone - sowie Einfluss von Alter und Fastendauer auf spezifische Stoffwechselhormone bei der Ratte, Impact of preanalytical factors on the concentration of specific metabolic hormones and effect of age and fasting on specific metabolic hormones in rats. Dissertation, LMU München: Tierärztliche Fakultät

from Elektronische Dissertationen der LMU München: http://ift.tt/1KsR6ln

Coronarographie par voie radiale : solutions contre le spasme

par Feno RABENIRINA Université Libre de Bruxelles (ULB) 2014

from Memoire Online http://ift.tt/1NiT8q3

Prévalence des infections des voies respiratoires superieures chez les enfants de 0 à 15 ans

par Bienvenu Kongolo Université de Kalemie 2015

from Memoire Online http://ift.tt/1NiT8q3

[hal-01108627] From complexity to algebra and back: digraph classes, collapsibility and the PGP

Inspired by computational complexity results for the quantified constraint satisfaction problem, we study the clones of idempotent polymorphisms of certain digraph classes. Our first results are two algebraic dichotomy, even "gap", theorems. Building on and extending [Martin CP'11], we prove that partially reflexive paths bequeath a set of idempotent polymorphisms whose associated clone algebra has: either the polynomially generated powers property (PGP); or the exponentially generated powers property (EGP). Similarly, we build on [DaMM ICALP'14] to prove that semicomplete digraphs have the same property. These gap theorems are further motivated by new evidence that PGP could be the algebraic explanation that a QCSP is in NP even for unbounded alternation. Along the way we also effect a study of a concrete form of PGP known as collapsibility, tying together the algebraic and structural threads from [Chen Sicomp'08], and show that collapsibility is equivalent to its Π2-restriction. We also give a decision procedure for k-collapsibility from a singleton source of a finite structure (a form of collapsibility which covers all known examples of PGP for finite structures). Finally, we present a new QCSP trichotomy result, for partially reflexive paths with constants. Without constants it is known these QCSPs are either in NL or Pspace-complete [Martin CP'11], but we prove that with constants they attain the three complexities NL, NP-complete and Pspace-complete. [Martin CP'11] Barnaby Martin: QCSP on Partially Reflexive Forests. CP 2011: 546-560 [DaMM ICALP'14] Petar Dapic, Petar Markovic, Barnaby Martin: QCSP on Semicomplete Digraphs. ICALP (1) 2014. [Chen Sicomp'08] Hubie Chen: The Complexity of Quantified Constraint Satisfaction: Collapsibility, Sink Algebras, and the Three-Element Case. SIAM J. Comput. 37(5): 1674-1701 (2008).

from HAL : Dernières publications http://ift.tt/1JrFVGG

[hal-01134194] Optimal Transport using Helmholtz-Hodge Decomposition and First-Order Primal-Dual Algorithms

This work deals with the resolution of the optimal transport problem between 2D images in the fluid mechanics framework of Benamou and Brenier formulation [1], which numerical resolution is still challenging even for medium-sized images. We develop a method using the Helmholtz-Hodge decomposition [2] in order to enforce the divergence-free constraint throughout the iterations. We then show how to use a first order primal-dual algorithm for convex problems of Chambolle and Pock [3] to solve the obtained problem, leading to a new algorithm easy to implement. Besides, numerical experiments demonstrate that this algorithm is faster than state of the art methods and efficient with real-sized images.

from HAL : Dernières publications http://ift.tt/1B7XFTz

[hal-01133948] Modélisations de textures par champ gaussien à orientation locale prescrite

Nous présentons dans ce papier deux nouveaux modèles de texture orientée, basés sur une nouvelle classe de champs gaussiens, appelés champs browniens fractionnaires localement anisotropes, à orientation locale prescrite en chaque point. Ces champs aléatoires sont une version locale d'une classe spécifique de champs anisotropes autosimilaires à incréments stationnaires. La simulation de telles textures s'appuie sur un nouvel algorithme couplant l'utilisation de la notion de champs tangents à la méthode de Cholesky ou plus récemment la méthode des bandes tournantes, cette dernière ayant prouvé son efficacité à générer des textures stationnaires anisotropes. Des applications numériques illustrent la faculté de la méthode à synthétiser des textures à orientation locale prescrite.

from HAL : Dernières publications http://ift.tt/1OJ2FIk

[hal-01170063] A Day-ahead Centralized Unit Commitment Algorithm for A Multi-agent Smart Grid

Renewable energy resources like wind and solar have become an effective factor in the energy production on the planet as they are inexhaustible renewable resources. However, they are very intermittent and their output cannot be predicted certainly. In this paper an algorithm of unit commitment within a power grid integrating wind and photovoltaic production units is proposed in a centralized approach that takes into account provisional data about the renewable energy production. Here the unit commitment problem is stated as a power demand coverage problem with some prespecified merit order list. A multi-agent architecture is proposed to facilitate the message exchange and easy addition and deletion of agents in the grid. This architecture is flexible and easy reconfigurable as it can provide solutions under assumptions of a decentralized approach. An implementation using JADE platform is presented in this work. The system is tested using real-data sets from an existent energy transport network in France (RTE). The results based on different operating conditions show the economic sense of the proposed strategy.

from HAL : Dernières publications http://ift.tt/1OJ4sNs

[hal-01133948] Modélisations de textures par champ gaussien à orientation locale prescrite

Nous présentons dans ce papier deux nouveaux modèles de texture orientée, basés sur une nouvelle classe de champs gaussiens, appelés champs browniens fractionnaires localement anisotropes, à orientation locale prescrite en chaque point. Ces champs aléatoires sont une version locale d'une classe spécifique de champs anisotropes autosimilaires à incréments stationnaires. La simulation de telles textures s'appuie sur un nouvel algorithme couplant l'utilisation de la notion de champs tangents à la méthode de Cholesky ou plus récemment la méthode des bandes tournantes, cette dernière ayant prouvé son efficacité à générer des textures stationnaires anisotropes. Des applications numériques illustrent la faculté de la méthode à synthétiser des textures à orientation locale prescrite.

from HAL : Dernières publications http://ift.tt/1OJ2FIk

[hal-01133948] Modélisations de textures par champ gaussien à orientation locale prescrite

Nous présentons dans ce papier deux nouveaux modèles de texture orientée, basés sur une nouvelle classe de champs gaussiens, appelés champs browniens fractionnaires localement anisotropes, à orientation locale prescrite en chaque point. Ces champs aléatoires sont une version locale d'une classe spécifique de champs anisotropes autosimilaires à incréments stationnaires. La simulation de telles textures s'appuie sur un nouvel algorithme couplant l'utilisation de la notion de champs tangents à la méthode de Cholesky ou plus récemment la méthode des bandes tournantes, cette dernière ayant prouvé son efficacité à générer des textures stationnaires anisotropes. Des applications numériques illustrent la faculté de la méthode à synthétiser des textures à orientation locale prescrite.

from HAL : Dernières publications http://ift.tt/1OJ2FIk

[hal-01202401] La gendarmerie et la protection de l’enfance sur Internet

La France a pris très rapidement en compte la spécificité du réseau Internet dans sa législation, comme le démontre la loi du 17 juin 1998 relative à la prévention et à la répression des infractions sexuelles. En matière de protection des mineurs sur Internet, la gendarmerie nationale s’est investie essentiellement dans le volet répressif, en étant présente sur l’ensemble des services proposés par ce média et avec une priorité dans la lutte contre la pédopornographie. Trois problématiques concernent plus particulièrement l’ensemble des services judiciaires, de police et de gendarmerie dans le monde entier : la diffusion d’images pornographiques mettant en scène des mineurs, la présence de pédophiles prédateurs sur les outils d’échange privilégiés par les mineurs et de manière plus large la diffusion de contenus pouvant heurter les jeunes publics. Les moyens humains mis en œuvre pour accomplir cette mission sont conséquents et déployés sur tout le territoire. Cela a permis d’obtenir très rapidement des résultats, l’expertise technique des enquêteurs étant reconnue notamment pour tout ce qui touche à l’exploitation des traces numériques. L’action des unités de gendarmerie se traduit avant tout par les nombreuses affaires judiciaires initiées au sein des unités locales.

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[insu-01164710] NEMOTAM: tangent and adjoint models for the ocean modelling platform NEMO

Tangent linear and adjoint models (TAMs) are efficient tools to analyse and to control dynamical systems such as NEMO. They can be involved in a large range of applications such as sensitivity analysis, parameter estimation or the computation of characteristic vectors. A TAM is also required by the 4D-Var algorithm, which is one of the major methods in data assimilation. This paper describes the development and the validation of the tangent linear and adjoint model for the NEMO ocean modelling platform (NEMOTAM). The diagnostic tools that are available alongside NEMOTAM are detailed and discussed, and several applications are also presented.

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[hal-01187162] Sampling, metamodelling and sensitivity analysis of numerical simulators with functional stochastic inputs

In this paper, we define a new methodology to perform sensitivity analysis of a computer simulation code in a particular case, whose study is motivated by a nuclear reliability application. This particular framework is characterized by three features. The first feature is that this kind of code is computationally expensive, which limits the number of available code evaluations. Second, code inputs are scalar and functional parameters, and the functional ones can be dependent. Third, the probability distribution of the functional inputs is not known; only a sample of their realizations is available. The proposed methodology is a combination and an adaption of existing methods. First, the functional input uncertainty is quantified via a functional decomposition combined with a sparse Gaussian mixture model. From this obtained probability density function, a method is proposed to sample uniformly both the functional and scalar input variation domain. Finally, variance-based sensitivity indices are estimated. This methodology is applied to an analytical example to evaluate this approach. Finally, the application to the nuclear reliability study is described.

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[hal-01187153] Stochastic Tracking of Mesoscale Convective Systems: Evaluation in the West African Sahel

In this work we apply a recently proposed Bayesian Multiple Target Tracking model to Mesoscale Convective Systems tracking. This stochastic model follows the Multiple Hypothesis Tracking paradigm and can handle a varying number of targets while detecting the target birth, death, split, and merge events. The model is tested experimentally with real MCS targets detected from Meteosat IR data over the Sahelian region. The performance of the stochastic tracking is evaluated by comparing it qualitatively and quantitatively with well established deterministic methods.

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[hal-00923735] Accounting for observation errors in image data assimilation

This paper deals with the assimilation of image-type data. Such kind of data, such as satellite images have good properties (dense coverage in space and time), but also one crucial problem for data assimilation: they are affected by spatially correlated errors. Classical approaches in data assimilation assume uncorrelated noise, because the proper description and numerical manipulation of non-diagonal error covariance matrices is complex. This paper propose a simple way to provide observation error covariance matrices adapted to spatially correlated errors. This is done using various image transformations: multiscale (wavelets, Fourier, curvelets), gradients, gradient orientations. These transformations are described and compared to classical approaches, such as pixel-to-pixel comparison and observation thinning. We provide simple yet effective covariance matrices for each of these transformations, which take into account the observation error correlations and improve the results. The effectiveness of the proposed approach is demonstrated on twin experiments performed on a 2D shallow-water model.

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[hal-01128420] Accounting for Missing Data in Sparse Wavelet Representation of Observation Error Correlations

One of the problems in numerical weather prediction is the determination of the initial state of the system. Indeed, the true state of the atmosphere and ocean, at a given moment and in all points of space, are not accessible. In order to retrieve an optimal initial condition one uses the so called data assimilation methods that combine information from observations, model equations and their respective error statistics. Since the late 70s, in numerical weather prediction, a dominant source of information comes from many satellites. Errors associated to such data are highly correlated in space, which can be detrimental if this is not properly accounted for. However their density in space allows for the efficient use of multi-scale transformation, which in turn permit a cheap but good approximation of said error statistics representation. The drawback of such approach is that the angling of missing data may not be trivial, the aim of this paper is to propose possible solutions to overcome this problem.

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[hal-01202398] L’Internet des objets : un nouveau champ d’action pour la cybercriminalité

L’observation de la cybercriminalité et des différentes formes d’abus dans l’utilisation des technologies numériques a montré au cours des dix dernières années que les activités illégales ne se contentaient plus d’un rôle marginal dans l’univers numérique, mues par des mobiles touchant à l’appropriation financière ou à l’appropriation informationnelle. L’émergence d’un Internet des objets en tant que support des activités humaines doit évidemment nous amener à prendre en compte ce type de risque, d’autant plus que les conséquences en sont encore difficiles à évaluer, ne serait-ce que par l’ampleur d’une telle évolution (le nombre des objets, des réseaux qui interagissent, des nouveaux usages étant considérable). C’est donc une multitude d’axes de recherche en matière de sécurité qui doivent être ouverts ou soutenus, y compris ceux qui permettront de tirer profit de ces nouvelles technologies pour améliorer la sécurité.

from HAL : Dernières publications http://ift.tt/1NMrGDb

[hal-01185255] About Interface Conditions for Coupling Hydrostatic and Nonhydrostatic Navier-Stokes Flows

In this work we are interested in the search of interface conditions to couple hydrostatic and nonhydrostatic ocean models. To this aim, we consider simplified systems and use a time discretization to handle linear equations. We recall the links between the two models (with the particular role of the aspect ratio δ = H/L 1) and introduce an iterative method based on the Schwarz algorithm (widely used in domain decomposition methods). The convergence of this method depends strongly on the choice of interface conditions: this is why we look for exact absorbing conditions and their approximations in order to provide tractable and efficient coupling algorithms.

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[hal-00982087] Towards optimized Schwarz methods for the Navier-Stokes equations

This paper presents a study of optimized Schwarz domain decomposition methods for Navier-Stokes equations. Once discretized in time, optimal transparent boundary conditions are derived for the resulting Stokes equations, and a series of local approximations for these nonlocal conditions are proposed. Their convergence properties are studied, and numerical simulations are conducted on the test case of the driven cavity. It is shown that conditions involving one or two degrees of freedom can improve the convergence properties of the original algorithm.

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[hal-01184711] Numerical modification of atmospheric models to include the feedback of oceanic currents on air-sea fluxes in ocean-atmosphere coupled models

In this note we present the modification to bring to an atmospheric model to account for relative winds (i.e. the difference between the near-surface winds and the oceanic currents) instead of absolute winds in the computation of air-sea fluxes. Because of the implicit treatment of the bottom boundary condition in most atmospheric models the use of relative winds involves a modification of both the surface layer parameterization and the tridiagonal matrix for vertical turbulent diffusion.

from HAL : Dernières publications http://ift.tt/1KoLwAF

[hal-01202398] L’Internet des objets : un nouveau champ d’action pour la cybercriminalité

L’observation de la cybercriminalité et des différentes formes d’abus dans l’utilisation des technologies numériques a montré au cours des dix dernières années que les activités illégales ne se contentaient plus d’un rôle marginal dans l’univers numérique, mues par des mobiles touchant à l’appropriation financière ou à l’appropriation informationnelle. L’émergence d’un Internet des objets en tant que support des activités humaines doit évidemment nous amener à prendre en compte ce type de risque, d’autant plus que les conséquences en sont encore difficiles à évaluer, ne serait-ce que par l’ampleur d’une telle évolution (le nombre des objets, des réseaux qui interagissent, des nouveaux usages étant considérable). C’est donc une multitude d’axes de recherche en matière de sécurité qui doivent être ouverts ou soutenus, y compris ceux qui permettront de tirer profit de ces nouvelles technologies pour améliorer la sécurité.

from HAL : Dernières publications http://ift.tt/1NMrGDb

[hal-01200624] Colloquium: Mechanical formalisms for tissue dynamics

The understanding of morphogenesis in living organisms has been renewed by tremendous progress in experimental techniques that provide access to cell scale, quantitative information both on the shapes of cells within tissues and on the genes being expressed. This information suggests that our understanding of the respective contributions of gene expression and mechanics, and of their crucial entanglement, will soon leap forward. Biomechanics increasingly benefits from models, which assist the design and interpretation of experiments, point out the main ingredients and assumptions, and ultimately lead to predictions. The newly accessible local information thus calls for a reflection on how to select suitable classes of mechanical models. We review both mechanical ingredients suggested by the current knowledge of tissue behaviour, and modelling methods that can help generate a rheological diagram or a constitutive equation. We distinguish cell scale (“intra-cell”) and tissue scale (“inter-cell”) contributions. We recall the mathematical framework developed for continuum materials and explain how to transform a constitutive equation into a set of partial differential equations amenable to numerical resolution. We show that when plastic behaviour is relevant, the dissipation function formalism appears appropriate to generate constitutive equations; its variational nature facilitates numerical implementation, and we discuss adaptations needed in the case of large deformations. The present article gathers theoretical methods that can readily enhance the significance of the data to be extracted from recent or future high throughput biomechanical experiments.

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[hal-01122681] Embedded Real-Time Localization of UAV based on an Hybrid Device

This paper presents a method for localizing an Unmanned Aerial Vehicle (UAV) in indoor or outdoor environments. The approach has the ability to estimate the 3D pose of the on-board camera by using a Harris corner detector and the Levenberg-Marquardt (LM) with the Random Sample Consensus (RANSAC) algorithm to perform detection. The implementation of such computational intensive tasks in embedded system is necessary for the autonomy of UAV. Accelerators implemented on FPGA provide a solution to reach required performances. In addition to the algorithm development, we present the embedding of a real time camera pose estimation algorithm on a Xilinx System on Programmable Chip (SoPC) platform. Partition- ing of our embedded application into hardware and software parts on a Zynq Board has significantly reduced the execution time when compared with software implementation, while offering necessary reconfiguration capabilities.

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[hal-01065979] Stability constraints for oceanic numerical models: implications for the formulation of time and space discretizations

Except for vertical diffusion (and possibly the external mode and bottom drag), oceanic models usually rely on explicit time-stepping algorithms subject to Courant-Friedrichs- Lewy (CFL) stability criteria. Implicit methods could be unconditionally stable, but an algebraic system must be solved at each time step and other considerations such as accuracy and efficiency are less straightforward to achieve. Depending on the target application, the process limiting the maximum allowed time-step is generally different. In this paper, we introduce offline diagnostics to predict stability limits associated with internal gravity waves, advection, diffusion, and rotation. This suite of diagnostics is applied to a set of global, regional and coastal numerical simulations with several horizontal/vertical resolutions and different numerical models. We show that, for resolutions finer that 1/2◦, models with an eulerian vertical coordinate are generally constrained by vertical advection in a few hot spots and that numerics must be extremely robust to changes in Courant number. Based on those results, we review the stability and accuracy of existing numerical kernels in vogue in primitive equations oceanic models with a focus on advective processes and the dynamics of internal waves. We emphasize the additional value of studying the numerical kernel of oceanic models in the light of coupled space-time approaches instead of studying the time schemes independently from spatial discretizations. From this study, we suggest some guidelines for the development of temporal schemes in future generation multi-purpose oceanic models.

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[halshs-01202395] Du succès du cessez-le-feu à l'échec de la paix, l'expérience des monts Nouba au Soudan (2002-2005)

From the Cease-fire Success to the Failure of Peace: the Nuba Mountains' Experiment in Sudan (2002-2005)

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[hal-00908997] L'érosion

[...]

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[hal-01023862] Stochastic Reliability Evaluation of Sea-of-Tiles Based on Double Gate Controllable-Polarity FETs

Promising devices like Double Gate Field Effect transistors [1] (DGFET) are proposed as basic elements to form tiles for a new kind of nanofabric [2]. For this fabric, regular arrays of tiles are expected in order to build a Sea-of-Tiles. DGGET transistors enable a concise expression of computational function. In order to facilitate this building, a specific logic synthesis methodology based on BBDD was proposed in [3]. We propose in this paper to evaluate the reliability of an application mapped onto this kind of fabric. Based on the BBDD representation of the application, we propose a more accurate stochastic method that takes care of the mapping of the application onto the regular fabric. Stochastic methods for reliability evaluation such as [4] [5] rely on bit streams or probabilistic transfer matrices. Unlike these methods, we propose to model the reliability problem of the nanofabric by means of Bayesian network. The usage of Bayesian methods is not completely new [6] [7] in the context of nanotechnology. Nevertheless, in this paper, we explore Bayesian methodologies for DGFET Sea-of-tiles nanofabric, by integrating them at the application level. This enables us to consider offline reliability strategies as well as online ones based on diagnosis capabilities of Bayesian networks, showing a real new opportunity for EDA tools

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[hal-01146318] FPGA Implementation of Bayesian Network Inference for an Embedded Diagnosis

[...]

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[hal-01146309] Bayesian Network-Based Framework for the Design of Reconfigurable Health Management Monitors

[...]

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[hal-01147706] Étude de l'activité d'un stagiaire d'EPS au travail et en vidéo-formation : Une « traçabilité » de l'évolution de l'intervention professionnelle

Cet article présente une étude de cas constitutive d'une recherche en ergonomie cognitive visant à décrire et interpréter l'activité déployée par des enseignants novices, alternativement au travail et en vidéo-formation autonome. L'analyse porte ici sur les significations produites pendant les navigations d'un enseignant sur une plateforme de vidéo-formation, ainsi que sur les effets géné-rés sur son activité de travail, lors de son entrée dans le métier. Les résultats montrent que ses connaissances professionnelles se créent et se transforment en réponse aux insatisfactions qui émergent pour lui envers son activité de travail, que ce soit au travail ou en en vidéo-formation, et se stabilisent si elles s'accordent à l'épreuve de cette même activité avec ses normes de viabilité per-sonnelles. Mots-clés: enseignants débutants, vidéo-formation, développement profession-nel, situations typiques d'enseignement, conception de formation. Abstract: This article presents a case study that is part of a larger research in a cognitive ergonomics approach, aiming at describing and interpreting the activity deployed by novice teachers alternatively while working and while video-training autonomously. The analysis deals here with the significations produced for a teacher while surfing on a video-training platform, and also with the effects generated on his work activity, during his entry into the profession. The findings show that his professional knowledge is created and transformed in response to dissatisfactions emerging for him toward his work activity, at work or during video-training sessions, and is stabilized if it accords, proof against this activity, with his personal norms of viability. Des outils numériques pour former les enseignants Durant ces vingt dernières années, la conception d'environnements numériques de formation a connu un développement conséquent. Elle s'accompagne d'un développement des pratiques et dispositifs d'e-learning et de formation hybride, en particulier pour les étudiants et professionnels novices, qui constitue un phénomène plus Recherches & Educations 2 récent mais grandissant (Albero, 2004). Le cas de la formation des futurs enseignants et des enseignants novices (EN par la suite) en est un bon exemple. Sa dimension professionnelle, voire professionnalisante, est fortement portée par l'institution qui mise objectivement sur ces nou-veaux espaces (Escalié & Chaliès, 2011). Selon Albero, bien que la re-cherche se soit largement emparée du champ des environnements numériques de formation, ses résultats ne se départissent pas pour autant d'un caractère émietté et non cumulatif ; ce constat est particulièrement vrai pour le cas des dispositifs de vidéo-formation des enseignants dont relève notre étude (Gaudin & Chaliès, 2012). En effet, bien que la formation des enseignants ait une longue tradition d'usage de la vidéo (Brouwer, 2007 ; Flandin, sous presse ; Leblanc & Veyrunes, 2012), la recherche peine à produire les études systématiques nécessaires à une véritable capitalisation des résultats. Dans ces conditions , étayer scientifiquement la conception de situations de formation reste difficile (Sherin, 2003). De plus, la plupart des études menées ne s'intéressent pas à l'impact des situations de vidéo-formation sur l'évolution réelle de l'activité professionnelle des enseignants, mais uni-quement à ce que ces derniers en disent (e.g. Moreno, Abercrombie & Hushman, 2009) ou à leurs intentions de changement (e.g. Meyer, David & Aubé, 2012). Elles présentent donc très peu souvent les données empi-riques nécessaires à cet objectif (Gaudin & Chaliès, 2012). Enfin, rares sont celles qui prennent en compte les significations que les enseignants attribuent à leur activité en formation ou au travail, et la singularité des situations analysées qui peut pourtant conditionner largement les effets produits par un même dispositif (Flandin & Ria, 2012b). C'est pourquoi notre recherche s'attache à composer avec ces différentes dimensions pour décrire la trajectoire de formation d'un EN et déterminer le rôle que peut y jouer l'utilisation d'un dispositif basé sur la vidéo.

from HAL : Dernières publications http://ift.tt/1FVwrCx

[hal-01202379] Sécurité informatique, cours et exercices corrigés

[...]

from HAL : Dernières publications http://ift.tt/1iGSUyu

[hal-01202378] Analysis of Rainbow Tables with Fingerprints

[...]

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[hal-01202377] Comparing distance bounding protocols: A critical mission supported by decision theory

[...]

from HAL : Dernières publications http://ift.tt/1V4y4Ke

[hal-01202376] Distance Geometry and Applications

[...]

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[hal-01202387] Réflexions sur les effets pragmatiques favorisés par la signification des particules discursives

[...]

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[hal-01092880] Un programme technologique basé sur l’analyse de l’activité réelle des enseignants débutants au travail et en vidéoformation

A technological program based on the analysis of the actual activity of beginning teachers at work and during video education. This article proposes an approach to the research-design of an educational device related to a logic of teacher professionalization, namely a logic of reasoning on and for the action (Barbier, 2006): the “NéoPass@ction” video platform. Beyond the technical aspects, the total device, which is supported by a hybrid program of research and engineering training, and which is described here on the basis of several complementary works: a) in situ analysis and modelling of the actual work of beginning teachers, b) the design of innovative resources documented through recorded interviews and testimonies and textual explanations and c) assessment of these resources and of the educational devices integrating them, for feedback purposes. These works are analysed using a ternary approach to training devices (Albero, 2010a). The first section describes the initial design process of the device, from ideational foundations (empirically and historically situated theoretical and ethical assumptions about teacher training) to a functional device of reference (explicit operational project, embodied by an online video platform). The second section describes the process of continued design: from the analysis of the lived device, on the users’ side, taking studies conducted in different educational contexts, we identify ways in which beginning teachers use NéoPass@ction and transform their relationship with work. In conclusion, we suggest possible improvements to the platform, along with supports for its use.

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[hal-01147706] Étude de l'activité d'un stagiaire d'EPS au travail et en vidéo-formation : Une « traçabilité » de l'évolution de l'intervention professionnelle

Cet article présente une étude de cas constitutive d'une recherche en ergonomie cognitive visant à décrire et interpréter l'activité déployée par des enseignants novices, alternativement au travail et en vidéo-formation autonome. L'analyse porte ici sur les significations produites pendant les navigations d'un enseignant sur une plateforme de vidéo-formation, ainsi que sur les effets géné-rés sur son activité de travail, lors de son entrée dans le métier. Les résultats montrent que ses connaissances professionnelles se créent et se transforment en réponse aux insatisfactions qui émergent pour lui envers son activité de travail, que ce soit au travail ou en en vidéo-formation, et se stabilisent si elles s'accordent à l'épreuve de cette même activité avec ses normes de viabilité per-sonnelles. Mots-clés: enseignants débutants, vidéo-formation, développement profession-nel, situations typiques d'enseignement, conception de formation. Abstract: This article presents a case study that is part of a larger research in a cognitive ergonomics approach, aiming at describing and interpreting the activity deployed by novice teachers alternatively while working and while video-training autonomously. The analysis deals here with the significations produced for a teacher while surfing on a video-training platform, and also with the effects generated on his work activity, during his entry into the profession. The findings show that his professional knowledge is created and transformed in response to dissatisfactions emerging for him toward his work activity, at work or during video-training sessions, and is stabilized if it accords, proof against this activity, with his personal norms of viability. Des outils numériques pour former les enseignants Durant ces vingt dernières années, la conception d'environnements numériques de formation a connu un développement conséquent. Elle s'accompagne d'un développement des pratiques et dispositifs d'e-learning et de formation hybride, en particulier pour les étudiants et professionnels novices, qui constitue un phénomène plus Recherches & Educations 2 récent mais grandissant (Albero, 2004). Le cas de la formation des futurs enseignants et des enseignants novices (EN par la suite) en est un bon exemple. Sa dimension professionnelle, voire professionnalisante, est fortement portée par l'institution qui mise objectivement sur ces nou-veaux espaces (Escalié & Chaliès, 2011). Selon Albero, bien que la re-cherche se soit largement emparée du champ des environnements numériques de formation, ses résultats ne se départissent pas pour autant d'un caractère émietté et non cumulatif ; ce constat est particulièrement vrai pour le cas des dispositifs de vidéo-formation des enseignants dont relève notre étude (Gaudin & Chaliès, 2012). En effet, bien que la formation des enseignants ait une longue tradition d'usage de la vidéo (Brouwer, 2007 ; Flandin, sous presse ; Leblanc & Veyrunes, 2012), la recherche peine à produire les études systématiques nécessaires à une véritable capitalisation des résultats. Dans ces conditions , étayer scientifiquement la conception de situations de formation reste difficile (Sherin, 2003). De plus, la plupart des études menées ne s'intéressent pas à l'impact des situations de vidéo-formation sur l'évolution réelle de l'activité professionnelle des enseignants, mais uni-quement à ce que ces derniers en disent (e.g. Moreno, Abercrombie & Hushman, 2009) ou à leurs intentions de changement (e.g. Meyer, David & Aubé, 2012). Elles présentent donc très peu souvent les données empi-riques nécessaires à cet objectif (Gaudin & Chaliès, 2012). Enfin, rares sont celles qui prennent en compte les significations que les enseignants attribuent à leur activité en formation ou au travail, et la singularité des situations analysées qui peut pourtant conditionner largement les effets produits par un même dispositif (Flandin & Ria, 2012b). C'est pourquoi notre recherche s'attache à composer avec ces différentes dimensions pour décrire la trajectoire de formation d'un EN et déterminer le rôle que peut y jouer l'utilisation d'un dispositif basé sur la vidéo.

from HAL : Dernières publications http://ift.tt/1FVwrCx

[hal-01202379] Sécurité informatique, cours et exercices corrigés

[...]

from HAL : Dernières publications http://ift.tt/1iGSUyu

[hal-01198996] Control in water adhesion of nanostructured parahydrophobic films using mesh substrates

The control in water adhesion is extremely requested for many applications in water harvesting, liquid transportation and water/oil separation, for example. Inspired by natural species such as rose petals and gecko foot, these properties can be controlled with the topography of surface structures. Here, we report for the first time the electrodeposition of sticking conducting polymers forming nanofilaments or nanosheets on textured mesh substrates. We show that the presence of mesh textures can reduce the water adhesion but it remains relatively high, which is probably due to a high amount of air between the mesh wires and a low amount on them. Moreover, it is also possible to control the water adhesion with the mesh opening or by modifying the shape of the nanostructures. This work opens new strategic ways in the control of water adhesion.

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[hal-01194425] Control of conducting polymer nanostructures for parahydrophobic properties

Controlling the water adhesion is fundamental for various applications such as in water harvesting or liquid transportation. In nature, superhydrophobic properties (high apparent contact angles and low water adhesion) as well as parahydrophobic properties (high contact angle and high water adhesion) are present in flora and fauna. Here, in order to reproduce parahydrophobic properties, nanostructured conducting polymers are elaborated by electropolymerization of 3,4-propylenedioxythiophene (ProDOT) bearing phenyl groups. The use of phenyl groups allows to reduce the polymer surface energy in comparison to long fluorocarbon of hydrocarbon chains. We show that various fibrous morphologies as well as the parahydrophobic properties can be controlled with the used electrolyte. This work is also important in the aim to replace long perfluorocarbon chains due to their bioaccumulative potential. This work also opens new doors to patent these kind of materials and to envisage their commercialization.

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[hal-01196694] Ant Colony Optimization with Environment Changes: an Application to GPS Surveying

We propose a variant on the well-known Ant Colony Optimization (ACO) general framework where we introduce the environment to play an important role during the optimization process. Together with diversification and intensification, the environment is introduced with the aim of avoiding the search to get stuck at local optima. In this work, the environment is simulated by means of the Logistic map, that is used in ACO for perturbing the update of the pheromone trails. Our preliminary experiments show that our environmental ACO (eACO), with variable environment, outperforms the standard ACO on a set of instances of the GPS Surveying Problem (GSP).

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[hal-01083405] Digital Trees and Memoryless Sources: from Arithmetics to Analysis

Digital trees, also known as "tries", are fundamental to a number of algorithmic schemes, including radix-based searching and sorting, lossless text compression, dynamic hashing algorithms, communication protocols of the tree or stack type, distributed leader election, and so on. This extended abstract develops the asymptotic form of expectations of the main parameters of interest, such as tree size and path length. The analysis is conducted under the simplest of all probabilistic models; namely, the memoryless source, under which letters that data items are comprised of are drawn independently from a fixed (finite) probability distribution. The precise asymptotic structure of the parameters' expectations is shown to depend on fine singular properties in the complex plane of a ubiquitous Dirichlet series. Consequences include the characterization of a broad range of asymptotic regimes for error terms associated with trie parameters, as well as a classification that depends on specific arithmetic properties, especially irrationality measures, of the sources under consideration.

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[hal-01083405] Digital Trees and Memoryless Sources: from Arithmetics to Analysis

Digital trees, also known as \emph``tries'', are fundamental to a number of algorithmic schemes, including radix-based searching and sorting, lossless text compression, dynamic hashing algorithms, communication protocols of the tree or stack type, distributed leader election, and so on. This extended abstract develops the asymptotic form of expectations of the main parameters of interest, such as tree size and path length. The analysis is conducted under the simplest of all probabilistic models; namely, the \emphmemoryless source, under which letters that data items are comprised of are drawn independently from a fixed (finite) probability distribution. The precise asymptotic structure of the parameters' expectations is shown to depend on fine singular properties in the complex plane of a ubiquitous \emphDirichlet series. Consequences include the characterization of a broad range of asymptotic regimes for error terms associated with trie parameters, as well as a classification that depends on specific \empharithmetic properties, especially irrationality measures, of the sources under consideration.

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[tel-01179587] Analysis and diagnosis of Web performances from an end-user perspective

In recent years, the interest of the research community in the performance of Web browsing has grown steadily. In order to reveal end-user perceived performance of Web browsing, in this thesis work, we address multiple issues of Web browsing performance from the perspective of the end-user. The thesis is composed by three parts: the first part introduces our initial platform which is based on browser-level measurements. We explain measurement metrics that can be easily acquired from the browser and indicators for end-user experience. Then, we use clustering techniques to correlate higher-level performance metrics with lower level metrics. In the second part, we present our diagnosis tool called FireLog. We first discuss different possible causes that can prevent a Web page to achieve fast rendering; then, we describe details of the tool's components and its measurements. Based on the measured metrics, we illustrate our model for the performance diagnosis in an automatic fashion. In the last part, we propose a new methodology named Critical Path Method for the Web performance analysis. We first explain details about Web browser's intrinsic features during page rendering and then we formalize our the methodology.

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[tel-01194802] Conception de systèmes multi-antennes multi-bandes pour terminaux mobiles LTE

Les techniques à base d’antennes multiples constituent une solution intéressante à l’augmentation du débit sans accroître la bande passante. Cependant, la conception de systèmes à base de diversité soulève de nouveaux défis quant à leur intégration au sein de terminaux à encombrement réduit. Le travail présenté consiste à prendre en compte conjointement les éléments déterminant les performances de communication multi-antennes et les contraintes d’intégration liées aux terminaux. Les systèmes développés fonctionnent dans deux bandes LTE: 790-862 MHz et 2.5-2.69 GHz; certains couvrent également la partie haute de la bande TVWS (TV White Space): 700-790 MHz afin d’offrir des applications de radio cognitive. Pour la première conception, la démarche consiste à obtenir un système performant sans rechercher, dans un premier temps une forte intégration. Néanmoins, le système proposé est intégrable dans des terminaux émergeant dans le marché actuel comme l’hybride téléphone-tablette. Des performances très satisfaisantes en termes de bandes et d’isolation sont atteintes. Ensuite, on privilégie la compacité du système tout en offrant des performances acceptables. Cette démarche permet la conception de trois prototypes, dont le dernier est intégrable dans un téléphone.D’autre part, l’influence de la présence d’un utilisateur mais également de l’intégration dans un terminal multimédia sur les performances des systèmes est étudiée. Enfin, les performances en diversité sont évaluées dans différentes configurations d’environnements. Les résultats ont montré que ces systèmes sont adaptés à la technologie LTE et offrent la possibilité d’établir des communications sans fil MIMO.

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[tel-01194884] Detection of logic flaws in multi-party business applications via security testing

Multi-party business applications are distributed computer programs implementing collaborative business functions. These applications are one of the main target of attackers who exploit vulnerabilities in order to perform malicious activities. The most prevalent classes of vulnerabilities are the consequence of insufficient validation of the user-provided input. However, the less-known class of logic vulnerabilities recently attracted the attention of researcher. According to the availability of software documentation, two testing techniques can be used: design verification via model checking, and black-box security testing. However, the former offers no support to test real implementations and the latter lacks the sophistication to detect logic flaws. In this thesis, we present two novel security testing techniques to detect logic flaws in multi-party business applicatons that tackle the shortcomings of the existing techniques. First, we present the verification via model checking of two security protocols. We then address the challenge of extending the results of the model checker to automatically test protocol implementations. Second, we present a novel black-box security testing technique that combines model inference, extraction of workflow and data flow patterns, and an attack pattern-based test case generation algorithm. Finally, we discuss the application of the technique developed in this thesis in an industrial setting. We used these techniques to discover previously-unknown design errors in SAML SSO and OpenID protocols, and ten logic vulnerabilities in eCommerce applications allowing an attacker to pay less or shop for free.

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[tel-01180009] A study of multi-standard radio transmitters for GSM/WCDMA/LTE base stations

Contemporary telecommunication Base-Stations for GSM/EDGE, WCDMA/HSPA and LTE are increasingly complex and energy intensive. The favoured solution is a truly multi-standard transmitter known as a single Radio Access Network (single-RAN). Modern base station transmitters are often multi-standard, in that they can support different air-interface standards or modes. However, this is achieved not through concurrent operation of the different standards or 'modes', but by means of reconfiguration, which is inefficient and expensive. We envision a practical, fully multi-mode transmitter capable of simultaneously supporting GSM/EDGE, WCDMA/HSPA and LTE carriers. The evolution of 3GPP standards towards multi-mode operation is in the nascent stage. To contribute to this effort, our work revisits the architecture of the traditional macro-cell Base-Station transmitter in order to analyse and define performance requirements for a multi-standard cellular radio platform. Our system analysis and design also identifies a potential bottleneck in the proposed multi-mode chain, for which analysis is presented. Consequently and lastly, we propose the conceptual design of a variable-gain Analog Quadrature Modulator that bypasses the bottleneck, highlighting scope for future development and validation of this work. This work also brings forth some system-level issues and also highlights challenges in the operation of multi-standard Base-Stations. Some of these include multi-mode signal crest-factor reduction, carrier-to-carrier interference mitigation, per-carrier power-control, etc.

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[tel-01183684] Multi-user communication systems : from interference management to network coding

This work is dedicated to the analysis, design and performance evaluation of physical layer network coding strategies in multiuser communication systems. The first part is devoted to study the compute-and-forward protocol in the basic multiple access channel. For this strategy, we propose an optimal solution to design efficient network codes based on solving a lattice shortest vector problem. Moreover, we derive novel bounds on the ergodic rate and the outage probability for the CF operating in fast and slow fading channels respectively. Besides, we develop novel decoding algorithms proved numerically to outperform the traditional decoding scheme for the CF. The second part is dedicated to the design and end-to-end performance evaluation of network codes for the CF and the analog network coding in the two-way relay channel and the multi-source multi-relay channel. For each network model we study the decoding at the relay nodes and the end destination, propose search algorithms for optimal network codes for the CF and evaluate, theoretically and numerically, the end-to-end error rate and achievable transmission rate. In the last part, we study new decoders for the distributed MIMO channel termed integer forcing (if). Inspired by the CF, if receivers take advantage of the interference provided by the wireless medium to decode integer linear combinations of the original codewords. We develop in our work efficient algorithms to select optimal if receivers parameters allowing to outperform existing suboptimal linear receivers

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[hal-00452702] Counting occurrences for a finite set of words: an inclusion-exclusion approach

In this paper, we give the multivariate generating function counting texts according to their length and to the number of occurrences of words from a finite set. The application of the inclusion-exclusion principle to word counting due to Goulden and Jackson (1979, 1983) is used to derive the result. Unlike some other techniques which suppose that the set of words is reduced (i.e., where no two words are factor of one another), the finite set can be chosen arbitrarily. Noonan and Zeilberger (1999) already provided a M APLE package treating the non-reduced case, without giving an expression of the generating function or a detailed proof. We give a complete proof validating the use of the inclusion- exclusion principle and compare the complexity of the method proposed here with the one using automata for solving the problem.

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[hal-01201984] DIFFUSIVE SCALING IN ENERGY GINZBURG-LANDAU DYNAMICS

Ginzburg-Landau energy models arise as autonomous sto-chastic dynamics for the energies in coupled systems after a weak coupling limit (cf. [3, 6]). We prove here that, under certain conditions, the energy fluctuations of these stochastic dynamics are driven by the heat equation, under a diffusive space time scaling.

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[hal-01202373] Chalcogénures pour le stockage de l’information : mémoires ioniques (CB-RAM) et mémoires à changement de phase (PC-RAM)

Les verres chalcogénures possèdent des propriétés uniques qui permettent d’envisager leur utilisation pour le développement de mémoires électriques susceptibles de remplacer les mémoires flash actuelles. D’une part, les verres sulfures et séléniures " dopés" par des ions argent présentent une conductivité ionique élevée, propriété qui pourrait être mise à profit pour le développement de mémoires ioniques CB-RAM. D’autre part, la haute photosensibilité des tellurures – matériaux à changement de phase – a permis le succès du développement puis de la commercialisation de dispositifs pour le stockage optique de l’information (CD-RW, DVD-RW, BD). Ces dernières années, ces matériaux font l’objet d’intenses recherches pour le développement de mémoires électriques PC-RAM. L’objectif de cet article est d’apporter un éclairage sur ces matériaux et sur les mécanismes susceptibles d’expliquer les commutations électriques en leur sein. Dans le cas des mémoires ioniques CB-RAM, nous avons d’abord réalisé une caractérisation structurale et électrique du matériau actif Agx(Ge0,25Se0,75)100−x sous forme de verre massif. Puis nous avons procédé à une étude de la commutation électrique au sein de multi-couches minces Ag/Ge25Se75 par une méthode innovante : la microscopie à force atomique conductrice (C-AFM). Dans le cas des mémoires PC-RAM, une étude systématique de couches épaisses amorphes du système GexTe100−x a été effectuée afin d’établir une corrélation entre la structure et le vieillissement des couches.

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[halshs-01202351] Les échecs des ONG humanitaires, un sujet tabou ?

Les échecs des opérations humanitaires ont-ils l'objet de tabous ? Se multiplient-ils avec la "professionnalisation" des ONG ? Révèlent-ils un monde compétitif où l'erreur n'est plus permise ? Sont-ils un indicateur de la dépendance croissante des ONG de leurs bailleurs de fonds ? ou d'une frgilisation due à la perte de contact direct avec le "terrain", c'est-à-dire avec les bénéficiaires, auprès desquels les humanitaires ne serient que des prestataires de service interchangeables ?

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[hal-01202274] Modèle électrique équivalent dédié à l'estimation d'associations série et parallèle de circuits rectennas à 2.45 GHz

no abstract

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[hal-01202311] Un désir citadin de nature… maîtrisée : quelle place pour les parcs naturels en ville ?

En se fondant sur la nomenclature du MEA (2005), l’UICN France (2013) détaille les services offerts par les écosystèmes urbains : -d’approvisionnement, source de biens utilisables par l’homme (nourriture…), -de régulation, assurant un environnement agréable (qualité de l’air…), -culturels, regroupant les bienfaits non matériels (loisirs…), -de support, permettant le maintien des trois précédents (biodiversité…). Il est maintenant acquis que les espaces de nature participent à la qualité de vie en ville ; les bénéfices pour les usagers sont nombreux (Konijnendijk et al., 2013 ; Long et Tonini, 2012…). Les villes en ont conscience et elles utilisent ces espaces comme argument de séduction, pour attirer de nouveaux habitants ; leurs élus les exploitent aussi, comme argument électoral. Les espaces verts concourent à améliorer l’image des villes, à les rendre attractives (Boutefeu, 2007). Dans le cadre du projet de recherche SERVEUR (SErvices Rendus par les espaces VErts URbains), financé par la région Centre, nous nous sommes intéressés aux services culturels et à la consommation des espaces de nature en ville. Ici, nous nous interrogeons plus particulièrement sur cet attrait exercé par les espaces verts : quelle nature en ville le citadin désire-t-il ? Cette nature prend des formes diverses, du parc d’agrément fortement ordonné au parc naturel, où la végétation croît spontanément. Quel type d’espaces verts les citadins plébiscitent-ils le plus ? S’agit-il des parcs naturels ? Comment les gestionnaires des espaces verts intègrent-ils cette préférence ? Afin d’identifier la demande de nature des citadins, à travers leurs usages et perceptions, et les pratiques de gestion résultantes, mises en place par les acteurs municipaux, nous avons mené dans plusieurs villes de la région Centre : -des observations non participantes, -des enquêtes in situ auprès des usagers, -des entretiens auprès des gestionnaires des espaces verts (élus, chefs de service et techniciens). De ce travail, il ressort que la nature urbaine doit être maîtrisée, pour les deux publics mais les justifications diffèrent. Pour les habitants, l’espace vert urbain est d’abord un espace récréatif, sécurisé et propre, avec des pelouses tondues, des arbres élagués et des parterres de fleurs sans cesse renouvelés. Les usages semblent confirmer cette idée. Les bois et espaces semi-naturels, catégorie dans laquelle entrent les parcs naturels, sont moins fréquentés que les parcs d’agrément. Pourtant, le citadin déclare apprécier la nature ; il réclame sa présence en ville. Mais il se plaint aussi des désagréments engendrés auprès des gestionnaires : il veut une nature qui ne salit pas (boue…) et voit dans le développement spontané de la végétation un manque d’entretien, une « nature en désordre » (termes d’un élu) qu’il dénonce. Pour les gestionnaires, la perception de la nature par le citadin est antagoniste ; il veut les avantages sans les inconvénients. Il désire en fait une nature contrôlée. Les acteurs municipaux en charge des espaces verts abondent dans le même sens, même si eux aussi déclarent vouloir « plus de nature » ; la raison donnée est que « la population ne suit pas » (selon un élu). En effet, les techniciens et chefs de service souhaitent que les espaces qu’ils gèrent soient fréquentés et les élus ont tout intérêt à satisfaire la demande de leurs électeurs. Les gestionnaires œuvrent ainsi pour une nature entretenue et surtout pour que cet entretien soit visible, même s’il faut concilier des pratiques écologiques, encouragées par les politiques publiques, et la lutte contre l’enfrichement et la « nature en désordre ». La gestion différenciée s’impose dans toutes les villes mais même les espaces verts les moins entretenus ne doivent pas apparaître négligés aux yeux des habitants ; les prairies sont fauchées, les bois éclaircis. Les dynamiques naturelles sont encadrées pour éviter toute « dérive » que peuvent représenter les herbes trop hautes, les feuilles qui tombent, le pollen… La présence des parcs naturels en ville semble paradoxalement être remise en cause par ce désir de nature urbaine qu’exprime le citadin et que tentent de satisfaire les gestionnaires, désir d’une nature maîtrisée, sans inconvénient. Boutefeu, E., 2007. « La nature en ville : des enjeux paysagers et sociétaux », Géoconfluences, http://ift.tt/1ip7ee1 (10/02/2015) Konijnendijk, C. C. et al., 2013. Benefits of Urban Parks. A systematic review. A Report for IFPRA, Copenhagen & Alnarp, 70 p. Long, N. et B. Tonini, 2012. « Les espaces verts urbains : étude exploratoire des pratiques et du ressenti des usagers », VertigO, vol. 12, n 2, http://ift.tt/1NKvF37 (18/12/2014) MEA (Millennium Ecosystem Assessment), 2005. Ecosystems and Human Well-being: Synthesis, Island Press, Washington DC UICN France, 2013. Panorama des services écologiques fournis par les milieux naturels en France, vol. 2.3 : les écosystèmes urbains, Paris, 20 p.

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[hal-01202296] Nonlinear predictive control based on artificial neural network model for industrial crystallization

This paper illustrates the benefits of a nonlinear model based predictive control (NMPC) strategy for setpoint tracking control of an industrial crystallization process. A neural networks model is used as internal model to predict process outputs. An optimization problem is solved to compute future control actions taking into account real-time control objectives. Furthermore, a more suitable output variable is used for process control: the mass of crystals in the solution is used instead of the traditional electrical conductivity. The performance of the NMPC implementation is assessed via simulation results based on industrial data.

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[hal-01202264] Lifetime optimization of wireless sensor network by a better nodes positioning and energy distribution

no abstract

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[hal-01202295] NMPC of an industrial crystallization process using model-based observers

This paper illustrates the benefits of a nonlinear model-based predictive control (NMPC) approach applied to an industrial crystallization process. This relevant approach proposes a setpoint tracking of the crystal mass. The controlled variable, unavailable, is obtained using an extended Luenberger observer. A neural network model is used as internal model to predict process outputs. An optimization problem is solved to compute future control actions taking into account real-time control objectives. The performances of this strategy are demonstrated via simulation in cases of setpoint tracking and disturbance rejection. The results reveal a significant improvement in terms of robustness and energy efficiency.

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[hal-01202263] Clustering and solar radiance prediction

no abstract

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[hal-01202294] A neural model-based auto-tuning PID strategy to improve an industrial sugar crystallization process control

no abstract

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[hal-01202262] Design and performance analysis of a small rectenna array for low wireless energy harvesting

no abstract

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[hal-01202293] Energy-Efficient Greedy Forwarding Protocol for Wireless Sensor Networks

In a wireless sensor network, as the sensor nodes have limited energy, it is important to minimize nodal energy consumption due to message communication to extend the network lifetime. Existing forwarding protocols either do not consider network performance and energy saving jointly, or they are not distributed. In this paper, we propose a hybrid approach, called minimum consumption maximum remaining energy (MIN-MAX-E) forwarding, which combines minimum energy consumption of transmitter-receiver pair along with maximum remaining energy of the receiver in making a relay node selection decision. Extensive simulation studies show that the proposed algorithm offers a significantly improved energy saving performance with respect to the existing energy-aware approaches.

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[hal-01202261] Neural Model-Based Self-Tuning PID Strategy Applied to PEMFC

no abstract

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[hal-01202292] Soft-sensor for industrial sugar crystallization: On-line mass of crystals, concentration and purity measurement

This paper deals with the design of a model-based soft-sensor to improve the process monitoring and control in industrial sugar crystallization. This soft-sensor is based on an original model dedicated to the last stage of crystallization, avoiding the solving of the population balance. Additional information like the mass of crystals in the solution, the concentration of dissolved sucrose and the purity are relevant to improve the manufacturing process. As these physicochemical properties are not measurable on-line, a model based soft-sensor is developed. The effectiveness of the soft sensor is demonstrated using real plant data from an industrial crystallization process.

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[tel-00452018] Les réseaux de neurones pour la modélisation et le contrôle du procédé d'évaporation : expérimentations et applications industrielles en sucrerie de canne

Ce travail de recherche, consacré à la synthèse d'une commande prédictive à modèle neuronal du procédé d'évaporation en multiple-effets, s'inscrit dans la continuité des travaux menés au L.G.I. depuis plusieurs années. Le mémoire de thèse s'articule en cinq chapitres : le premier présente l'atelier d'évaporation dans la chaîne de fabrication du sucre, et les développements théoriques et expérimentaux nécessaires à l'identification d'un modèle dynamique du procédé. Le chapitre 2 pose les bases théoriques du transfert technologique que constitue l'application des réseaux de neurones pour la modélisation et le contrôle des procédés industriels. La première partie de ce transfert technologique, décrite dans le chapitre 3, concerne l'identification de modèles du procédé d'évaporation, à partir de données expérimentales issues des campagnes de mesure menées à la sucrerie de Bois Rouge, La Réunion, en 1997 et 1998, et la simulation des modèles identifiés. Dans le chapitre 4, la problématique de l'automatisation du procédé, confrontée aux limites rencontrées par les schémas de régulation traditionnels, justifie la mise en oeuvre d'une stratégie de commande avancée. Cette démarche, qui constitue la deuxième partie du transfert technologique que nous avons entrepris, aboutit à la mise en oeuvre d'un schéma de commande prédictive mono variable basée sur un modèle à réseau de neurones, testé en simulation dans le chapitre 5. L'ensemble des résultats de simulation sont prometteurs, ce qui permet d'envisager l'implantation d'une stratégie similaire in situ dans les meilleurs délais.

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[hal-00635877] A Raman lidar at La Reunion (20.8° S, 55.5° E) for monitoring water vapor and cirrus distributions in the subtropical upper troposphere: preliminary analyses and description of a future system

A ground based Rayleigh lidar has provided continuous observations of tropospheric water vapor profiles and cirrus cloud using a preliminary Raman channels setup on an existing Rayleigh lidar above La Reunion over the period 2002-2005. With this instrument, we performed a first measurement campaign of 350 independent water vapor profiles. A statistical study of the distribution of water vapor profiles is presented and some investigations concerning the calibration are discussed. The data set having several long acquisition measurements during nighttime, an analysis of the diurnal cycle of water vapor has also been investigated. Analysis regarding the cirrus clouds is presented and a classification has been performed showing 3 distinct classes. Based on these results, the characteristics and the design of a future lidar system to be implemented at the new Reunion Island altitude observatory (2200 m) for long-term monitoring is presented and numerical simulations of system performance have been realized to compare both instruments.

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[hal-01202260] Thrust produced by corona discharge - Application to electrohydrodynamic propulsion

no abstract

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[hal-01202310] Industrial multi-step forward predictor of mother liquor purity of the final stage of a cane sugar crystallisation plant

In Bois Rouge sugar mill, the sugar cane crystallisation process is performed in three stages. During the third stage: C crystallisation, the mother liquor exhaustion is the main function, because it is the ultimate step of transforming saccharose in liquid form into crystals. In order to build a predictive scheme to control the C crystallisation, we decided to identify a multi-step ahead predictor of the mother liquor purity. The identification is performed using databases collected in situ. The present work deals with the four different steps of classical identification, from the databases to the predictor performances. In an industrial context, the measurements are often noisy or incomplete, so we have developed a neural network model well adapted to this type of data. Three different predictors have been identified and their performances show that an adaptive form of the predictor is the most appropriate for performing this task.

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[hal-01202309] Modelling and simulation of a complete system of energy transmission

This article presents an equivalent circuit approach used for the modelling of a system consisting of an antenna and a RF/DC rectifying circuit (rectenna) at 2.45 GHz. The measurements and simulations steps used for parameter extraction and model validation are presented. The major interest in this approach is the ability to study a complete system of energy transmission in a single simulator environment. This method is illustrated in the case of a microwave transmission without any modulation, that is to say the derived model can be easily integrated. The results obtained using this simple example show a relatively good agreement with the experiment and can form the basis for further developments of more complex systems

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[hal-01202308] Performance and instabilities of proton exchange membrane fuel cells

Performance of proton exchange fuel cells with different membrane and electrode assembly (MEA) is studied. It is shown that MEA fabricated with catalyst plasma pulverization technology has the maximum performance. Some instabilities in the cell performance, observed with time, are probably due to periodic cathode flooding.

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[hal-01202307] Supervision of C crystallisation in Bois Rouge sugar mill using on-line crystal content estimation using synchronous microwave and refractometric brix measurements

The sugar cane crystallisation process is currently performed through three stages. The efficiency of the third stage, named C crystallisation, is of high interest because it is the ultimate step of transforming saccharose in liquid form into crystals. In most of industries, the control of C crystallisation is performed following an electrical conductivity setpoint of the sucrose solution. However, this measurement presents several disadvantages which can damage the process control. In order to perform an efficient supervision of C crystallisation in Bois Rouge sugar mill, we have equipped the pan with two different brix sensors. Due to their costs, these measurements are seldom used in sugar industry. This work does show the benefits using these measurements to observe the process advancement of several crystallisation during the 2003 campaign.

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[hal-01202306] High efficiency microwave rectenna circuit: modelling and design

An equivalent circuit approach used for the modelling of a system consisting of an antenna and an RF/DC rectifying circuit (rectenna) is presented. It is shown that using this approach, no electromagnetic simulation tool is required for the simulation and optimisation of the overall circuit. The realised rectenna operates at 2.45 GHz, and shows very good agreement between the predicted efficiency using the presented model (about 75 ) and the measured one.

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[hal-01202305] Losses analysis and performance improvement of a rectenna for RFID systems

The research developed in this paper lies in the framework of the Wireless Power Transportation (WPT) applied to the RFID. The carried study aims at to obtain the best efficiency of the collecting/rectifying part of the WPT system (rectenna) where recovery of the microwave energy into continuous energy takes place. The optimization is performed on an equivalent circuit approach of the rectenna with the use of only a single non-linear circuit simulator environment. Furthermore, this method allows for the physical origin of the energy losses in the system to be quantified. Thereby, it will then be possible to improve the efficiency of the rectenna by working onto each element of the circuit.

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[hal-01202304] Low energy clustering adaptation protocol for an adhoc wireless sensor network

Energy dissipation in a Wireless Sensor Network is an active research field. Energy dissipation is related to the network topology and protocol used to route data. So, two criteria are proposed to elect a relay. A linear or a random choice from a set of potential nodes to become a relay based on their energy level above a mean threshold energy. These criteria improve the organization of the node communications and the lifetime of the network. The criteria and the protocol called the Self Organization One Hop Low Energy Clustering Adaptation (SOORLECA) are explained. The SOORLECA is designed for environmental and military monitoring with precise requisite measures at each node. No mean data or smoothing data technique is required at the Sink Node (SN). Random topology of the network for 100 nodes over 100m2 are simulated to show the protocol performances compared to direct transmission of the node to the SN, short routing path and static clustering protocols. The lifetime and the dissipated energy of the network are our criteria to measure the performance of the WSN. It is shown that the SOORLECA ACMET1 improves 2x the lifetime of network with 61% dissipated energy after 50% of nodes have dead.

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[hal-01202302] Herbicides pendant la guerre du Việt Nam : irréversibilité des dégâts sur l’environnement ? Exemple de la vallée d’A Lưới

Pendant la guerre du Việt Nam, l’armée américaine a déversé plus de 70 millions de litres d’herbicides. L’objectif était de détruire les cultures de l’ennemi et de supprimer le couvert foliaire sous lequel il se dissimulait. Pour certains, ces produits chimiques ont laissé des « marques indélébiles sur les paysages » (Ramade, 1990). N’omettent-ils pas le fait que la cicatrisation des écosystèmes s’inscrit dans le temps long ? Y a-t-il vraiment irréversibilité des dégâts ? Notre contribution se fondera sur des cartes de dynamiques paysagères, pendant et après la guerre, et sur des relevés de sols. Les herbicides ont contaminé les sols. Le composé le plus persistant est la dioxine. Or, dans les zones touchées par les épandages aériens de la vallée d’A Lưới, cette dernière atteint désormais des taux « acceptables » ; les mesures demeurent inquiétantes dans les anciennes bases des Forces spéciales, où étaient stockés les herbicides (Hatfield Consultants LTD et 10-80 Committee, 2000). Contaminés, les sols ont aussi été modifiés, notamment leurs propriétés chimiques (Hoàng Van Huây et Nguyên Xuân Cu, 1984). Néanmoins, les impacts ne sont autres que ceux qui résultent de tout déboisement, quelle qu’en soit la cause. La stérilisation des sols, avancée par les partisans de l’impossible reconquête végétale, est remise en cause. L’impact sur la végétation est indéniable mais doit être relativisé. Les traînées d’épandage ne sont plus visibles dans les paysages des années 2000. La destruction de la végétation a en fait été variable, notamment selon le nombre d’épandages et la formation végétale touchée. Par ailleurs, les pratiques post-guerre ont aggravé le strict impact de la défoliation. Hatfield Consultants Ltd et 10-80 Committee (2000), Development of Impact Mitigation Strategies Related to the Use of Agent Orange Herbicide in the Aluoi Valley,Viet Nam, West Coast Reproduction Centres LTD, Vancouver, Canada, vol. 1: Rapport, 157 p. + figures, tableaux et planches ; vol. 2: Appendices, 341 p. Hoàng Van Huây et Nguyên Xuân Cu (1984), “Long-term changes in soil chemistry following herbicidal attack”, dans WESTING, Ar. H. (dir.) (1984), Herbicides in war: The long term ecological and human consequences, Stockolm International Peace Research Institute (SIPRI), Taylor & Francis, Philadelphie, p. 69-73. Ramade, F. (1990), « Des pesticides aux armes chimiques », La Recherche, mars, n° 219, vol. 21, p. 382-390.

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[hal-01202303] Model based Soft-Sensor for Industrial Crystallization: On-line Mass of Crystals and Solubility Measurement

Monitoring and control of cane sugar crystallization processes depend on the stability of the supersaturation (σ ) state. The most widely used information to represent σ is the electrical conductivity κ of the solutions. Nevertheless, previous studies point out the shortcomings of this approach: κ may be regarded as inappropriate to guarantee an accurate estimation of σ in impure solutions. To improve the process control efficiency, additional information is necessary. The mass of crystals in the solution ( c m ) and the solubility (mass ratio of sugar to water / s w m m ) are relevant to complete information. Indeed, c m inherently contains information about the mass balance and / s w m m contains information about the supersaturation state of the solution. The main problem is that c m and / s w m m are not available on-line. In this paper, a model based soft-sensor is presented for a final crystallization stage (C sugar). Simulation results obtained on industrial data show the reliability of this approach, c m and the crystal content ( cc ) being estimated with a sufficient accuracy for achieving on-line monitoring in industry

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[hal-01202301] Control improvement of a C sugar cane crystallization using an auto tuning PID controller based on linearization of a neural network

The industrial process of the sugar cane crystallization produces a residual that still contains a lot of soluble sucrose and the objective of the factory is to improve its extraction. Therefore, there are substantial losses justifying the search for the optimization of the process. Crystallization process studied on the industrial site is based on the “three massecuites process". The third step of this process constitutes the final stage of exhaustion of the sucrose dissolved in the mother liquor. During the process of the third step of crystallization (Ccrystallization), the phase that is studied and whose control is to be improved, is the growing phase (crystal growth phase). The study of this process on the industrial site is a problem in its own. A control scheme is proposed to improve the standard PID control law used in the factory. An auto-tuning PID controller based on instantaneous linearization of a neural network is then proposed.

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[hal-01202300] An integrated model of a wireless power transportation for RFID and WSN applications

In this paper a simple and efficient model is proposed to predict the received direct current (DC) power in wireless power transportation (WPT) systems, for radio frequency identification (RFID) and wireless sensor network applications. The conversion of radio frequency (RF) power into usable DC power is done by a rectenna (a rectifying circuit with an antenna). The DC power was estimated using a model that takes into account the distance between the antennas, the power transmitted, the reflection and the diffraction mechanism associated with the laboratory environment, and the load value. For this purpose, the analytical model is compared to measurement results. This model was implemented in a RF simulation environment.

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[hal-01202299] Soft-sensor for on-line mass of crystals measurement: application to cane sugar crystallization

no abstract

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[hal-01202298] On-line estimation of mother liquor purity during the final stage of a cane sugar crystallization plant using neural network model.

The design of a soft-sensor to improve the monitoring of the sugar crystallization process is examined. Information about the mother liquor purity is relevant to improve the manufacturing process, especially during the last stage of three massecuites, called C crystallization. However, this piece of information is not available on-line and requires the development of a soft-sensor. In industrial context the measurements are often incomplete and/or noisy, therefore an input-output model is chosen instead of a knowledge one. An artificial neural network model is used to predict on-line the evolution of the purity of the solution during the crystallization process. The validation step is performed using industrial databases and experimental results show the efficiency of the proposed soft-sensor.

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[hal-01202297] A greedy minimum energy consumption forwarding protocol for wireless sensor networks

Energy consumption is a vital resource to be controlled to extend the longevity of a wireless sensor network. In a multihop routing, lifetime as well as throughput of the network could be increased by selecting the forwarding node intelligently. The existing energy-aware routing protocols either do not jointly consider the network performance and energy saving, or they are not distributed. In this paper, we propose an efficient greedy forwarding protocol, called minimum energy consumption forwarding, which selects a forwarding node on the basis of minimum transmit and receive energy consumption per successful packet transmission per unit Euclidean distance progress toward the destination, in a distributed fashion. In the proposed algorithm, at each hop the forwarding decision can be either taken by the transmitter at each forwarding node or the best forwarder can be elected by some kind of election contention mechanism. Through network simulations we have shown that the proposed energy consumption minimizing distributed forwarding strategy outperforms the greedy geographic forwarding algorithm in terms of increasing the network lifetime and end-to-end throughput. The proposed algorithm can be easily retrofitted in the already developed network capable wireless sensor nodes.

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[hal-01202296] Nonlinear predictive control based on artificial neural network model for industrial crystallization

This paper illustrates the benefits of a nonlinear model based predictive control (NMPC) strategy for setpoint tracking control of an industrial crystallization process. A neural networks model is used as internal model to predict process outputs. An optimization problem is solved to compute future control actions taking into account real-time control objectives. Furthermore, a more suitable output variable is used for process control: the mass of crystals in the solution is used instead of the traditional electrical conductivity. The performance of the NMPC implementation is assessed via simulation results based on industrial data.

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[hal-01202295] NMPC of an industrial crystallization process using model-based observers

This paper illustrates the benefits of a nonlinear model-based predictive control (NMPC) approach applied to an industrial crystallization process. This relevant approach proposes a setpoint tracking of the crystal mass. The controlled variable, unavailable, is obtained using an extended Luenberger observer. A neural network model is used as internal model to predict process outputs. An optimization problem is solved to compute future control actions taking into account real-time control objectives. The performances of this strategy are demonstrated via simulation in cases of setpoint tracking and disturbance rejection. The results reveal a significant improvement in terms of robustness and energy efficiency.

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[hal-01202294] A neural model-based auto-tuning PID strategy to improve an industrial sugar crystallization process control

no abstract

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[hal-01202293] Energy-Efficient Greedy Forwarding Protocol for Wireless Sensor Networks

In a wireless sensor network, as the sensor nodes have limited energy, it is important to minimize nodal energy consumption due to message communication to extend the network lifetime. Existing forwarding protocols either do not consider network performance and energy saving jointly, or they are not distributed. In this paper, we propose a hybrid approach, called minimum consumption maximum remaining energy (MIN-MAX-E) forwarding, which combines minimum energy consumption of transmitter-receiver pair along with maximum remaining energy of the receiver in making a relay node selection decision. Extensive simulation studies show that the proposed algorithm offers a significantly improved energy saving performance with respect to the existing energy-aware approaches.

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[hal-01202292] Soft-sensor for industrial sugar crystallization: On-line mass of crystals, concentration and purity measurement

This paper deals with the design of a model-based soft-sensor to improve the process monitoring and control in industrial sugar crystallization. This soft-sensor is based on an original model dedicated to the last stage of crystallization, avoiding the solving of the population balance. Additional information like the mass of crystals in the solution, the concentration of dissolved sucrose and the purity are relevant to improve the manufacturing process. As these physicochemical properties are not measurable on-line, a model based soft-sensor is developed. The effectiveness of the soft sensor is demonstrated using real plant data from an industrial crystallization process.

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[hal-01149957] Taux de recouvrement sur le demi-cercle grâce au théorème de la moyenne. TR(cercle)=CONSTANTE=1,14152016... en rapport avec pi.

Il s'agit de faire la somme des surfaces moyennes et de la comparer à la surface d'un demi-cercle. On s'aperçoit que quelque soit le rayon du cercle on trouve une constante ( T.R. ou taux de recouvrement).

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[hal-01154801] Taux de recouvrement sur la demi-ellipse grâce au théorème de la moyenne. TR(ellipse)=TR(cercle)=CONSTANTE=1,14152016...

RECHERCHE : Taux de recouvrement sur l'ellipse grâce au théorème de la moyenne. Il s'agit de la somme des surfaces moyennes de la demi-ellipse rapportée à la surface de la demi-ellipse. On obtient une constante qui ne dépend pas des paramètres de l'ellipse (a et b). TR (cercle) = TR (ellipse) = 1.14152016....

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[hal-01149957] Taux de recouvrement sur le demi-cercle grâce au théorème de la moyenne. TR(cercle)=CONSTANTE=1,14152016... en rapport avec pi.

Il s'agit de faire la somme des surfaces moyennes et de la comparer à la surface d'un demi-cercle. On s'aperçoit que quelque soit le rayon du cercle on trouve une constante ( T.R. ou taux de recouvrement).

from HAL : Dernières publications http://ift.tt/1NJZgJX

[hal-01154801] Taux de recouvrement sur la demi-ellipse grâce au théorème de la moyenne. TR(ellipse)=TR(cercle)=CONSTANTE=1,14152016...

RECHERCHE : Taux de recouvrement sur l'ellipse grâce au théorème de la moyenne. Il s'agit de la somme des surfaces moyennes de la demi-ellipse rapportée à la surface de la demi-ellipse. On obtient une constante qui ne dépend pas des paramètres de l'ellipse (a et b). TR (cercle) = TR (ellipse) = 1.14152016....

from HAL : Dernières publications http://ift.tt/1ioRHLo