Search

International audience; The paper presents results from the Collaborative Computational Project in Wave Structure Interaction (CCP-WSI) Blind Test Series 2. Without prior access to the physical data, participants, with numerical methods ranging from low-fidelity linear models to fully non-linear Navier–Stokes (NS) solvers, simulate the interaction between focused wave events and two separate, taut-moored, floating structures: a hemispherical-bottomed cylinder and a cylinder with a moonpool. The ‘blind’ numerical predictions for heave, surge, pitch and mooring load, are compared against physical measurements. Dynamic time warping is used to quantify the predictive capability of participating methods. In general, NS solvers and hybrid methods give more accurate predictions; however, heave amplitude is predicted reasonably well by all methods; and a WEC-Sim implementation, with CFD-informed viscous terms, demonstrates comparable predictive capability to even the stronger NS solvers. Large variations in the solutions are observed (even among similar methods), highlighting a need for standardisation in the numerical modelling of WSI problems.

International audience; Polarity-controlled growth of ZnO by chemical bath deposition provides a method for controlling the crystal orientation of vertical nanorod arrays. The ability to define the morphology and structure of the nanorods is essential to maximizing the performance of optical and electrical devices such as piezoelectric nanogenerators; however, well-defined Schottky contacts to the polar facets of the structures have yet to be explored. In this work, we demonstrate a process to fabricate metal−semiconductor−metal device structures from vertical arrays with Au contacts on the uppermost polar facets of the nanorods and show that the Opolar nanorods (∼0.44 eV) have a greater effective barrier height than the Znpolar nanorods (∼0.37 eV). Oxygen plasma treatment is shown by cathodoluminescence spectroscopy to affect midgap defects associated with radiative emissions, which improves the Schottky contacts from weakly rectifying to strongly rectifying. Interestingly, the plasma treatment is shown to have a much greater effect in reducing the number of carriers in O-polar nanorods through quenching of the donor-type substitutional hydrogen on oxygen sites (HO) when compared to the zinc-vacancy-related hydrogen defect complexes (VZn −nH) in Zn-polar nanorods that evolve to lowercoordinated complexes. The effect on HO in the O-polar nanorods coincides with a large reduction in the visible-range defects, producing a lower conductivity and creating the larger effective barrier heights. This combination can allow radiative losses and charge leakage to be controlled, enhancing devices such as dynamic photodetectors, strain sensors, and light-emitting diodes while showing that the O-polar nanorods can outperform Zn-polar nanorods in such applications.

International audience; Precisely detecting solar Active Regions (AR) from multi-spectral images is a challenging task yet important in understanding solar activity and its influence on space weather. A main challenge comes from each modality capturing a different location of these 3D objects, as opposed to more traditional multi-spectral imaging scenarios where all image bands observe the same scene. We present a multi-task deep learning framework that exploits the dependencies between image bands to produce 3D AR detection where different image bands (and physical locations) each have their own set of results. We compare our detection method against baseline approaches for solar image analysis (multi-channel coronal hole detection, SPOCA for ARs (Verbeeck et al., 2013)) and a state-of-the-art deep learning method (Faster RCNN) and show enhanced performances in detecting ARs jointly from multiple bands.

International audience; Fluoride-Ion Batteries (FIBs) have been recently proposed as a post-lithium-ion battery system. This review article presents recent progress of the synthesis and application aspects of the cathode, electrolyte, and anode materials for fluoride-ion batteries. In this respect, improvements in solid-state electrolytes for FIBs as well as liquid electrolytes will be discussed. Furthermore, the achievements regarding the development of cathode and anode materials will be considered. With the improvements made, the field is currently attracting a steady increase of interest, and we will discuss the potentials of this technology together with necessary future milestones to be achieved in order to develop FIBs for future energy storage.

Precisely localising solar Active Regions (AR) from multi-spectral images is a challenging but important task in understanding solar activity and its influence on space weather. A main challenge comes from each modality capturing a different location of the 3D objects, as opposed to typical multi-spectral imaging scenarios where all image bands observe the same scene. Thus, we refer to this special multi-spectral scenario as multi-layer. We present a multi-task deep learning framework that exploits the dependencies between image bands to produce 3D AR localisation (segmentation and detection) where different image bands (and physical locations) have their own set of results. Furthermore, to address the difficulty of producing dense AR annotations for training supervised machine learning (ML) algorithms, we adapt a training strategy based on weak labels (i.e. bounding boxes) in a recursive manner. We compare our detection and segmentation stages against baseline approaches for solar image analysis (multi-channel coronal hole detection, SPOCA for ARs) and state-of-the-art deep learning methods (Faster RCNN, U-Net). Additionally, both detection and segmentation stages are quantitatively validated on artificially created data of similar spatial configurations made from annotated multi-modal magnetic resonance images. Our framework achieves an average of 0.72 IoU (segmentation) and 0.90 F1 score (detection) across all modalities, comparing to the best performing baseline methods with scores of 0.53 and 0.58, respectively, on the artificial dataset, and 0.84 F1 score in the AR detection task comparing to baseline of 0.82 F1 score. Our segmentation results are qualitatively validated by an expert on real ARs.

International audience; Silicone rubbers are promising materials that have extensively been used in many areas, including wearable electronic devices, actuator materials in soft robotics, and energy harvesters. Ecoflex, a commercially available polymer, is a group of silicone rubbers appearing with various Shore hardnesses that has become popular in recent years. While silicone rubbers in their real applications are subjected to repeated loadingunloading conditions, their mechanical behaviour under cyclic loading in different deformation modes and the corresponding stress recovery behaviour are yet to be well investigated. In this contribution, we conduct loading-unloading cyclic experiments in different time gaps between the first cycle and the second cycle to demonstrate the stress recovery behaviour after stress softening happens during the first cycle. For that, three different modes of deformations, i.e., uniaxial tension, planar tension, and equibiaxial tension tests are selected. Besides, Shore hardness dependence with different strain levels is also taken into consideration. The results show that the stress softening could recover significantly with time. These findings will help to understand the mechanical behaviour of Ecoflex silicone rubbers before selecting them in practical applications that are exposed to repeated loading-unloading cycles.

International audience; Scanning transmission electron microscopy experiments indicate that face-centered cubic (FCC) is the predominant ordered structure for Ag309 ± 7 nanoclusters, synthesized in vacuum. Historically, experiments do not present a consensus on the morphology at these sizes, whereas theoretical studies find the icosahedral symmetry for Ag309 and the decahedral shape for nearby sizes. We employ density functional theory calculations to rationalize these observations, considering both regular and defective Ag nanoparticles (281–321 atoms). The change of stability induced by the presence of defects, symmetry loss, and change of number of atoms is evaluated by the nanoparticle surface energy, which was measured previously. FCC and decahedral symmetries are found to be more favorable than icosahedral, consistent with our measurements of clusters protected from extended atmospheric exposure. In addition, an energy-free descriptor, surface atomic density, is proposed and qualitatively reproduces the surface energy data. Nonsymmetric and defective structures may be preferred over perfectly regular ones within a given size range.

International audience; The polar and piezoelectric nature of the wurtzite structure of ZnO nanowires with a high aspect ratio at nanoscale dimensions is of high interest for piezotronic and piezoelectric devices, but a number of issues related to polarity are still open and deserve a particular attention. In this context, chemical bath deposition offers a unique opportunity to select the O-or Zn-polarity of the resultant nanowires and is further compatible with the fabrication processes of flexible devices. The control and use of the polarity in ZnO nanowires grown by chemical bath deposition open a new way to greatly enhance the performance of the related piezotronic and piezoelectric devices. However, polarity as an additional tunable parameter should be considered with care because it has a strong influence on many processes and properties. The present review is intended to report the most important consequences related to the polarity in ZnO nanowires for piezotronic and piezoelectric devices. After introducing the basic principles involving crystal polarity in ZnO, a special emphasis is placed on the effects of polarity on the nucleation and growth mechanisms of ZnO nanowires using chemical bath deposition, defect incorporation and doping, electrical contacts and device properties.

International audience; High dose selenium acts as a cytotoxic agent, with potential applications in cancer treatment. However, clinical trials have failed to show any chemotherapeutic value of selenium at safe and tolerated doses (

Nanotechnologies have reached maturity and market penetration that require nano‐specific changes in legislation and harmonization among legislation domains, such as the amendments to REACH for nanomaterials (NMs) which came into force in 2020. Thus, an assessment of the components and regulatory boundaries of NMs risk governance is timely, alongside related methods and tools, as part of the global efforts to optimise nanosafety and integrate it into product design processes, via Safe(r)‐by‐Design (SbD) concepts. This paper provides an overview of the state‐of‐the‐art regarding risk governance of NMs and lays out the theoretical basis for the development and implementation of an effective, trustworthy and transparent risk governance framework for NMs. The proposed framework enables continuous integration of the evolving state of the science, leverages best practice from contiguous disciplines and facilitates responsive re‐thinking of nanosafety governance to meet future needs. To achieve and operationalise such framework, a science‐based Risk Governance Council (RGC) for NMs is being developed. The framework will provide a toolkit for independent NMs' risk governance and integrates needs and views of stakeholders. An extension of this framework to relevant advanced materials and emerging technologies is also envisaged, in view of future foundations of risk research in Europe and globally., This study received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No 814425 (RiskGONE) and No 814572 (NanoSolveIT).

International audience; Silicone polymers have enormous applications, especially in the areas of biomedical engineering. Ecoflex, a commercially available room temperature cured silicone polymer, has attracted considerable attention due to its wide range of applications as medical-grade silicones and as matrix materials in producing nano-filled stretchable sensors and dielectric elastomers for soft robotics. In this contribution, we have conducted a wide range of experiments under thermo-mechanical loadings. These experiments consist of loading-unloading cyclic tests, single-step relaxation tests, Mullins effects tests at different strain rates and stretches, stress recovery tests at different rest time etc. In order to assess the temperature influences on Ecoflex, a number of viscoelastic tests are performed in a thermal chamber with temperature ranging from-40 • C to 140 • C. Extensive experimental findings illustrate that Ecoflex experiences a significant stress softening in the first cycles and such a softening recovers gradually with respect to time. It also shows a significant amount of cyclic dissipation at various stretch levels as well as a considerable stress relaxation only for virgin samples. Cyclic dissipations and stress relaxation almost disappear for the case of pre-stretched samples. Furthermore, the material is more or less sensitive under a wide range of temperature differences.

International audience; According to a recent Hume-Rothery approach, the electron concentration, e/a, and the average radius can be used to identify the domain of stability of HEAs and to estimate the phases that may occur in the alloy. The present study investigates the influence of the electronic polymorphism of nickel on the efficiency of the classification and on the design of HEAs for magnetic applications. Many different compositions were used, based on 4 to 7 elements out of a total 13 different elements (Co, Cr, Fe, Ni, Al, Cu, Pd, Ti, Mn, V, Nb, Sn, Ru). Phases have been determined by X-ray and neutron diffraction as well as in some cases high energy X-ray diffraction. The e/a for the constituent elements is calculated according to Massalski. The two polymorphic electronic structure of nickel, namely (e/a) Ni ¼ 1 or (e/a) Ni ¼ 2 are considered. The average e/a for the alloy is calculated assuming a solid solution case. The electronic structure [Ar] 3d 9 4s 1 seems to be more appropriate for the classification of HEAs. Based on a Self-organising Map predictions are made for the average magnetic moment at saturation for this electronic structure of Ni. Non-saturated values and data from the literature are compared with the predictions. The consequences of such results when modelling the structure and properties of Ni containing HEAs are presented, in particular the consideration of the shape and transformation of the Brillouin zone.

Workshop, Due to the COVID-19 pandemic, the event has been cancelled.; International audience; Art and design are essential aspects of our culture and how we interact with the world. Artists and designers use a wide selection of tools, whose impact is rapidly growing with the progression of digital technologies. This change has opened up new opportunities for the CHI community to build creative supportive tools. The digital switch has come with many benefits such as lowering barriers, mobile work environments and mass production for distribution of work. Along with these benefits we also see challenges for art and design work and its future perception in society. As technology takes a more significant role in supporting art and design what will this mean for the individual artist or designer? The focus of this workshop is to bring together researchers and practitioners to explore what the future of digital art and design will hold. The exploration will centre around synthesizing key challenges and questions, along with ideas for future interaction technologies that consider mobile and tangible aspects of digital art.

Goal: This manuscript evaluates atrioventric-ular valve regurgitation (AVVR) in babies born with an already very challenging heart condition, i.e., with single ventricle physiology. Although the second surgery that single ventricle patients undergo is thought to decrease AVVR, there is much controversy in the clinical literature about AVVR treatment. Methods: The effect of AVVR on Stage 1 haemodynamics and resulting acute changes from conversion to Stage 2 circulation in single ventricle patients are analyzed through lumped parameter models. Several degrees of AVVR severity are analyzed, for two types of valve regurgitation: incomplete leaflet closure and valve prolapse. Results: The models show that increasing AVVR in Stage 1 induces the following effects: first, higher stroke volume and associated decrease in ventricular end-systolic volume; second, increase in atrial volumes with V-loop enlargement in pressure-volume curves; third, pulmonary venous hypertension. The Stage 2 surgery results in volume unloading of the ventricle, thereby, driving a decrease in AVVR. However, this effect is offset by an increase in ventricular pressures resulting in a net increase in regurgitation fraction (RF) of approximately 0.1 (for example, in severe AVVR, the preoperative RF increases from $\sim$ 60% to $\sim$ 70% postoperatively). Moreover, despite some improvements to sarcomere function early after Stage 2 surgery, it may deteriorate in cases of severe AVVR. Conclusion: In patients with moderate to severe AVVR, restoration of atrioventricular valve competence prior to, or at the time of, Stage 2 surgery would likely lead to improved haemodynamics and clinical outcome as the models suggest that uncorrected AVVR can worsen across Stage 2 surgery. This was found to be independent of the AVVR degree and mechanisms.

International audience; The tensile-shear strength of AA 5052 single and multi-friction stir spot welding joints were analyzed using experimental, numerical, and analytical approaches. Benchmark specimens were designed and manufactured in a similar manner with respect to industrial practice. Under the fixed welding process condition, the failure mechanism of friction stir spot welded specimens under tensile-shear loading was first determined by using macro- and micro-structural analysis. It is shown that increasing the tool shoulder diameter and the number of friction stir spot weldings may nonproportionally increase the strength of the joints. In the linearly arranged multi-friction stir spot welding joints, the strength of these joints was discussed using analytical approach. It is demonstrated that in certain cases, increasing the nugget diameter is preferred than increasing the number of nuggets. This is only applicable to a certain friction stir spot welding failure mechanism. A finite element model prediction tool was developed to predict the tensile-shear strength of friction stir spot welded joints using the material properties obtained from the measurement of experimental hardness.

International audience; Turbulence is a crucial flow phenomenon for tidal energy converters (TECs), as it influences both the peak loads they experience and their fatigue life. To best mitigate its effects we must understand both turbulence itself and how it induces loads on TECs. To that end, this paper presents the results of blade element momentum theory (BEMT) simulations of flume-scale TEC models subjected to synthetic turbulent flows. Synthetic turbulence methods produce three-dimensional flowfields from limited data, without solving the equations governing fluid motion. These flowfields are non-physical, but match key statistical properties of real turbulence and are much quicker and computationally cheaper to produce. This study employs two synthetic turbulence generation methods: the synthetic eddy method and the spectral Sandia method. The response of the TECs to the synthetic turbulence is predicted using a robust BEMT model, modified from the classical formulation of BEMT. We show that, for the cases investigated, TEC load variability is lower in stall operation than at higher tip speed ratios. The variability of turbine loads has a straightforward relationship to the turbulence intensity of the inflow. Spectral properties of the velocity field are not fully reflected in the spectra of TEC loads.

International audience; Cost, driven mostly by planned and unplanned maintenance, is the most significant barrier limiting widespread adoption of TECs. Accurate numerical models can be used to predict the structural loads on TECs and help improve their reliability. BEMT offers an efficient method for predicting the performance of TECs. A robust but unoptimized BEMT code, implemented in MATLAB, has been developed at Swansea University. Previous versions of the BEMT code only allowed for inputs of constant blade profile and Reynolds Number which contributed to the inaccuracies of the BEMT model in predicting experimental results. We present a faster and more accurate C++ implementation of the BEMT code. The error between the coefficient of power from the BEMT code and results of laboratory testing at optimum TSR was reduced by 13%. This should in turn improve the design of TEC, reducing their cost and increase their adoption as generators of low carbon energy.

Part 6: Social Media and Analytics; International audience; Social media platforms are an inexpensive communication medium help to reach other users very quickly. The same benefit is also utilized by some mischievous users to post objectionable images and symbols to certain groups of people. This types of posts include cyber-aggression, cyberbullying, offensive content, and hate speech. In this work, we analyze images posted on online social media sites to hurt online users. In this research, we designed a deep learning based system to classify aggressive post from a non-aggressive post containing symbolic images. To show the effectiveness of our model, we created a dataset crawling images from Google search to query aggressive images. The validation shows promising results.

Touchscreens are the predominant medium for interactions with digital services; however, their current fixed form factor narrows the scope for rich physical interactions by limiting interaction possibilities to a single, planar surface. In this paper we introduce the concept of PickCells, a fully reconfigurable device concept composed of cells, that breaks the mould of rigid screens and explores a modular system that affords rich sets of tangible interactions and novel across-device relationships. Through a series of co-design activities – involving HCI experts and potential end-users of such systems – we synthesised a design space aimed at inspiring future research, giving researchers and designers a framework in which to explore modular screen interactions. The design space we propose unifies existing works on modular touch surfaces under a general framework and broadens horizons by opening up unexplored spaces providing new interaction possibilities. In this paper, we present the PickCells concept, a design space of modular touch surfaces, and propose a toolkit for quick scenario prototyping.

Low threshold coherent emission at 1.5 &micro, m is achieved using Er3+-doped dielectric 1D microcavities fabricated with a Radio Frequency-sputtering technique. The microcavities are composed of a half-wavelength Er3+-doped SiO2 active layer inserted between two Bragg reflectors consisting of ten, five, and seven pairs of SiO2/TiO2 layers, also doped with Er3+ ions. The morphology of the structure is inspected using scanning electron microscopy. Transmission measurements show the third and first order cavity resonance at 530 nm and 1.5 &micro, m, respectively. The photoluminescence measurements are obtained using the optical excitation at the third order cavity resonance using a 514.5 nm Ar+ laser or Xe excitation lamp at 514.5 nm, with an excitation angle of 30&deg, The full width at half maximum of the emission peak at 1535 nm decreased with the pump power until the spectral resolution of the detection system was 2.7 nm. Moreover, the emission intensity presents a non-linear behavior with the pump power and a threshold at about 4 &micro, W.

Part 1: E-Business; International audience; Social commerce is emerging as an important platform in e-commerce. It brings people to the comfort zone to buying and selling product that they cannot reach physically. The purpose of this research is to review the empirical research on social commerce published between 2012 to 2019. The paper mainly reviews the theories and models used in this area and limitations acknowledged by studies in social commerce area. The findings indicated that TAM, social support theory and S-O-R model are some of the most frequently used models. Also, use of biased sample, limited factors and cross-sectional studies are some of the most common limitations used across majority of studies.

Part 3: Smart Cities; International audience; Seventeen United Nations Development Goals (UN SDG) focus on peace and prosperity for people and the planet. Smart cities can help in achieving UN SDG. This research carries out a comprehensive analysis of the role of smart cities on creating sustainable cities and communities, which is one of 17 UN sustainable goals. Current research focuses on number of aspect of sustainable environment such as renewable and green energy, energy efficiency, environmental monitoring, air quality, and water quality. This study provides a valuable synthesis of the relevant literature on smart cities by analysing and discussing the key findings from existing research on issues of smart cities in creating sustainable cities and communities. The findings of this study can provide an informative framework for research on smart cities for academics and practitioners.

In this paper, we present a comprehensive analytical model of Tm able to take into account direct cross-relaxation process. We show that by using an appropriate set of parameters the model is able to properly fit the first part of the fluorescence decay of Tm-doped tellurite glasses for different dopant concentration values. We also compare the model with a full numerical model to investigate its limitations. We assess the model is a valid tool to fit fluorescence properties but for precisely predicting population inversion is limited to doping level up to about 1%. In fact, we show the reverse cross-relaxation process becomes significant in case of higher doping level., This article is based upon work from H2020 COST Action MP1401 on “Fiber Lasers and Their Applications” supported by COST “(European Cooperation in Science and Technology)”.

International audience; All Er3+ doped dielectric 1-D microcavity was fabricated by rf sputtering technique. The microcavity was constituted by half wave Er3+ doped SiO2 active layer inserted between two Bragg reflectors consists of ten pairs of SiO2/TiO2 layers also doped with Er3+ ions. The scanning electron microscopy was used to check the morphology of the structure. Transmission measurements confirm the third and first order cavity resonance at 530 nm and 1560 nm, respectively. The photoluminescence measurements were obtained by optically exciting at the third order cavity resonance using 514.5 nm Ar+ laser with an excitation angle of 30°. The Full Width at Half Maximum of the emission peak at 1560 nm decrease with the pump power until the spectral resolution of the detection system of ∼1.0 nm. Moreover, the emission intensity presents a non-linear behavior with the pump power and a threshold at about 24 mW was observed with saturation of the signal at above 185 mW of pump power.

Part 1: E-Business; International audience; In light of the very high popularity of electronic word of mouth in the form of products and services reviews on the internet and its critical importance for businesses, the aim of this research is to investigate why customers who buy skincare products do not engage in eWOM by not leaving reviews about these products online. This research adopts a qualitative nature, using semi-structured in-depth interviews. Respondents’ group consists of the same amount of males and females who were asked questions regarding their electronic and traditional word of mouth experiences. Received responses demonstrate that laziness, lack of general interest in skin care and lack of feeling altruistic towards consumers online are the key factors preventing consumers from leaving reviews about skin care online.

High entropy CrxAlFeCoNi alloys with x = 0, 0.5, 1.0 and 1.5 were synthesized using arc-melting and sintering preparation techniques. Three crystal structures (fcc, bcc and σ) were observed using XRD technique, while EDX measurements showed the presence of up to three chemically different phases (FeCr-rich phase with fcc structure, AlNi-rich phase with bcc structure and Cr-rich phase with bcc and/or σ structures). The reasons for the observed phase coexistence were addressed to total energy electronic structure calculations using KKR-CPA method accounting for chemical disorder effects. Such theoretical analysis confirmed that the multi-phase system was energetically more favorable than the single-phase one. Furthermore, DSC measurements allowed to identify two phase transitions in melted samples, unlike sintered ones due to high-temperature nitrogen corrosion. This process turned out to be highly selective, resulting in the formation of the scales consisting of AlnNm–phases at the cost of total Al loss in the HEA alloy.

Part 3: Government and Infrastructure; International audience; Lack of public participation in various policy making decision has always been a major cause of concern for government all around the world while formulating as well as evaluating such policies. With availability of latest IT infrastructure and the migration of government think-tank towards realizing more efficient cloud based e-government, this problem has been partially answered, but this predicament still persists. However, the exponential rise in usage of social media platforms by general public has given the government a wider insight to overcome this long pending dilemma. This paper presents a pragmatic approach that combines the capabilities of cloud computing and social media analytics towards efficient monitoring and controlling of public policies. The proposed arrangement has provided us some encouraging results, when tested for the policy of the century i.e. GST implementation by Indian government and established that proposed system can be successfully implemented for efficient policy making and implementation.

International audience; The temperature and time dependent structure of molten NiP alloy of eutectic composition has been studied by neutron diffraction. Ni particles were found to exist in the melt at temperatures at least up to about 150 degrees above liquidus. The amount varies reversibly as temperature increases but decays slowly with time. Remarkably, particles still exist even after that the melt has been kept more than 30 h at different temperatures in the molten state. The static structure factor and the pair distribution function obtained at 1050 °C are presented.

International audience; Mobile phone subscriptions are the largest form of consumer technology adopted across the world. Despite their potential, the research is very scant in understanding various predictors of consumer adoption towards mobiles technologies in particular mobile applications. This study intend to fulfil this purpose through weight analysis on mobile application adoption based studies that utilized UTAUT2 model. Studies needed for weight analysis were located through cited reference search method in Scopus and Web of Science bibliographic databases. The results of weight analysis revealed performance expectancy/perceived usefulness, trust and habit as best predictors of consumer behavioural intention to mobile applications adoption whereas behavioural intention was the best predictor of use behaviour. There were also two promising predictors with perfect weight of one such as perceived risk on behavioural intention and habit on use behaviour. Further steps of this research involves meta-analysis to develop comprehensive conceptual model concurrent with weight analysis results for empirical evaluation on various mobile applications.

There are countless sources of data available to governments, companies, and citizens, which can be combined for good or evil. We analyse the concepts of combining data from common sources and linking data from different sources. We model the data and its information content to be found in a single source by a partial ordered monoid, and the transfer of information between sources by different types of morphisms. To capture the linkage between a family of sources, we use a form of Grothendieck construction to create a partial ordered monoid that brings together the global data of the family in a single structure. We apply our approach to database theory and axiomatic structures in approximate reasoning. Thus, partial ordered monoids provide a foundation for the algebraic study for information gathering in its most primitive form., For WADT'18

To emphasize the scientific and technological interest in the silica-based glassy systems and the versatility of the sol-gel route, nano and micrometer scale structures are discussed focusing the attention mainly on the rare-earth-activated materials and their spectroscopic characterization. We have demonstrated that various SiO2-based binary systems can be successfully employed for the fabrication of amorphous planar waveguides, glass–ceramic waveguides, and tapered rib waveguide laser. Different technological processes allowed to realize Er3+ -activated microspheres that can be exploited as microresonator and it has been evidenced that through specific coating it is possible to modify modal free spectral range and/or modal dispersion of the microresonator and achieve laser action. In the case of rare-earth-doped 3-D colloidal crystals in different configurations (direct and inverse one), it has been shown that the relaxation dynamics of the electronic states can be engineered.

The Advanced Solid State Lasers 2017 Conference (ASSL) was held from October 1 to 5, 2017. It was an extraordinary conference at the Nagoya Congress Center in Nagoya, Japan. ASSL 2017 again suggested an impressive platform where miscellaneous perceptions with a variety of approaches to optics, photonics, sensing, laser technology, laser systems, and solid state lasers were presented. This international meeting was highly selective, leading to high level contributions through one plenary conference, 17 invited presentations, 70 regular talks, and 121 posters. The present joint issue of Optics Express and Optical Materials Express features 27 articles written by ASSL 2017 authors and covering the spectrum of solid-state lasers from materials research to sources, and from design innovation to applications.

International audience; All Er3+ doped dielectric 1-D microcavity are fabricated by RF sputtering technique. The microcavity is composed of half wave Er3+ doped SiO2 active layer inserted, between two Bragg reflectors consisting of seven pairs of SiO2/TiO2 layers also doped with Er3+ ions. The morphology of the structure is inspected with scanning electron microscopy. Transmission measurements show the third and first order cavity resonance at 530 nm and 1535 nm, respectively. The photoluminescence measurements were obtained by optically exciting at the third order cavity resonance using 514.5 nm Ar+ laser with an excitation angle of 30°. The Full Width at Half Maximum of the emission peak at 1535 nm decrease with the pump power until the spectral resolution of the detection system of 2.3 nm. Moreover, the emission intensity presents a non-linear behavior with the pump power and a threshold at about 4 μW.

International audience; Decidability of type checking for dependently typed languages usually requires a decidable equality on types. Since bisimilarity on (weakly final) coalgebras such as streams is undecidable, one cannot use it as the equality in type checking. Instead, languages based on dependent types with decidable type checking such as Coq or Agda use intensional equality for type checking. Two streams are definitionally equal if the underlying terms reduce to the same normal form, i.e. if the underlying programs are syntactically equivalent. For reasoning about equality of streams one introduces bisimilarity as a propositional rather than judgemental equality.In this paper we show that it is not possible to strengthen intensional equality in a decidable way while having the property that equality respects one step expansion, which means that a stream with head n and tail s is equal to $\mathrm {cons}(n,s)$ cons(n,s). This property, which would be very useful in type checking, would not necessarily imply that bisimilar streams are equal, and we prove that there exist equalities with this properties which do not coincide with bisimilarity. Whereas a proof that bisimilarity on streams is undecidable is straightforward, proving that respecting one step expansion makes equality undecidable is much more involved and relies on an inseparability result for sets of codes for Turing machines. We prove this theorem both for streams with primitive corecursion and with coiteration as introduction rule.Therefore, pattern matching on streams is, understood literally, not a valid principle, since it assumes that every stream is equal to a stream of the form $\mathrm {cons}(n,s)$ cons(n,s). We relate this problem to the subject reduction problem found when adding pattern matching on coalgebras to Coq and Agda. We discuss how this was solved in Agda by defining coalgebras by their elimination rule and replacing pattern matching on coalgebras by copattern matching, and how this relates to the approach in Agda which uses the type of delayed computations, i.e. the so called “musical notation” for codata types.

Ice velocity is one of the products associated with the Ice Sheets Essential Climate Variable. This paper describes the intercomparison and validation of ice-velocity measurements carried out by several international research groups within the European Space Agency Greenland Ice Sheet Climate Change Initiative project, based on space-borne Synthetic Aperture Radar (SAR) data. The goal of this activity was to survey the best SAR-based measurement and error characterization approaches currently in practice. To this end, four experiments were carried out, related to different processing techniques and scenarios, namely differential SAR interferometry, multi aperture SAR interferometry and offset-tracking of incoherent as well as of partially-coherent data. For each task, participants were provided with common datasets covering areas located on the Greenland ice-sheet margin and asked to provide mean velocity maps, quality characterization and a description of processing algorithms and parameters. The results were then intercompared and validated against GPS data, revealing in several cases significant differences in terms of coverage and accuracy. The algorithmic steps and parameters influencing the coverage, accuracy and spatial resolution of the measurements are discussed in detail for each technique, as well as the consistency between quality parameters and validation results. This allows several recommendations to be formulated, in particular concerning procedures which can reduce the impact of analyst decisions, and which are often found to be the cause of sub-optimal algorithm performance. Keywords: ice velocity; Synthetic Aperture Radar; Greenland ice sheet; Climate Change Initiative

International audience; This work focuses on the fabrication processes and photonic assessment of SiO2-SnO2:Er3+ monoliths. To obtain the crack-free and densified system, the sol-gel derived synthesis protocols and heat-treatment processes were optimized. The absorption measurements were employed to assess the effect of the heat-treatment on the samples and specially to estimate the –OH content. The XRD patterns were used to investigate the crystallization as well as the structure of the monoliths. The emission spectra, performed at different excitation wavelengths, evidence the presence of Er3+ in the SnO2 nanocrystals and the energy transfer from SnO2 to the rare earth ions. In addition, the efficient role of SnO2 nanocrystals as Er3+ sensitizers are also experimentally confirmed in this system.

Part 3: Government and Infrastructure; International audience; The rapid evolution of mobile-based technologies and applications has led to the development of several different forms of digital payment methods (DPMs) but with limited enthusiasm in consumers for adopting them. Hence, several academic studies have already been conducted to examine the role of various antecedents that determines consumers’ intention to adopt DPMs. The degree of effect and significance of several antecedents found to be inconsistent across different studies. This provided us a basis for undertaking a meta-analysis of existing research for estimating the cumulative effect of such antecedents. Therefore, this study aims to perform a meta-analysis of five antecedents (i.e. attitude, cost, mobility, price value and innovativeness) for confirming their overall influence on intentions to adopt DPMs. The results of this study suggest that the cumulative effect of four out of five antecedents found to be significant while influence of price value was found insignificant on behavioural intentions. The recommendations drawn from this research would help to decide if and when to use such antecedents for predicting consumer intention to adopt DPMs.

International audience; Electronic word of mouth (eWOM) plays an important part in our everyday life. eWOM communications have been shown to affect the adoption of information, thus affecting the information seeker’s decision-making. Identifying and studying how motivations to seek eWOM affect information adoption can prove beneficial in aiding new product, services and, in general, technology strategy development and adoption. This research aims at developing a model to investigate how certain specific motivations may affect the adoption of information sought through eWOM. This paper develops a set of hypotheses to help evaluate how motivations affect the information seeker’s adoption of the information sought, based on the moderating effect of gender. The paper improves on the knowledge of factors affecting information adoption and the impact of gender, and thus help advance our understanding of consumer behaviour online and information processing. Future empirical research will test the proposed hypotheses to advance our understanding of the role of motivations when seeking eWOM information.

In this paper, we numerically investigate the effect of the reverse cross-relaxation process on the inversion population of laser levels in Tm- doped glass based active system. We show the impact may be significant when high inversion population is required.

The Hume-Rothery approach applied in terms of e/a to classify and design quasicrystals and BMG is revisited for the case of HEAs. The results were compared with other parameters used in the literature, namely VEC and delta. The Self-Organizing Map tool is used to classify the experimental results and the experimental map is used to compare the predictions of phases and properties of compositions reported in the literature. According to the Hume-Rothery approach, e/a and the average radius can give a precise rule of thumb to identify the domain of stability of HEAs and to estimate the phases that may occur in the alloy: i) e/a 2.05: bcc. Moreover, e/a is to be preferred to VEC to classify phases in HEAs. Self-organizing maps can be used to make interpolative predictions for new compositions of HEAs with suitable phases for specific properties. Thus, simple combination of e/a and r gives an accurate first estimation to identify compositions with simple phases giving simple diffraction patterns, thus true HEAs as opposed to other compositional domains where complex phases occur.

International audience; Graphical sliders are widely used on mobile devices. However, with a single hand, reaching for far values is difficult : users change their grip and can drop the device. Moreover, sliders require visual attention to operate them. Envisioning mobile devices that dynamically extend tangible sliders out of the screen, the contribution of this work is a first attempt to experimentally study a deformable tangible slider that facilitate thumb interaction on mobile devices. The deformable tangible slider expands its cursor (Figure 1) to avoid hand-grip changes by maintaining the thumb within its comfortable area. Moreover, its tangible aspect allows eyes-free interaction. We first compared a low-fidelity prototype with a classic tangible slider. The prototype improves performance by 9.2% when targets are outside the thumb's comfortable area. We then designed a de-formable slider that we compared to a classic tangible slider and a graphical one. Though the deformable slider is globally faster (14.3%) than the classic tangible one, the difference is not significant. While the graphical slider performs faster, the deformable tangible slider o ers eyes- free interaction and stable hand-grip.; Les curseurs graphiques sont largement utilisés sur les dispositifs mobiles. Cependant, atteindre des valeurs éloignées avec le pouce de la main qui tient le dispositif est difficile : les utilisateurs changent alors la prise en main du dispositif au risque de le faire tomber. De plus, les curseurs graphiques sollicitent l’attention visuelle pour les manipuler. En anticipant que les dispositifs mobiles pourront faire émerger de leurs écrans des curseurs physiques dynamiquement, notre contribution est une première exploration expérimentale d’un curseur tangible qui se déforme pour faciliter l’interaction mobile avec le pouce de la main qui tient le dispositif. Le curseur tangible se déforme pour que le pouce manipule toujours le curseur dans la zone d’action facilement atteignable (Fig. 1). Le curseur tangible déformable (1) évite les changements de prise en main en maintenant le pouce dans sa zone de confort, et (2) permet une interaction sans regarder le dispositif mobile. Nous avons d’abord comparé un prototype basse-fidélité avec un curseur classique tangible. Le prototype améliore les performances de 9.2% lorsque les cibles sont en dehors de la zone de confort du pouce. Nous avons ensuite conçu un curseur déformable que nous avons comparé à un curseur tangible classique et à un curseur graphique. Les résultats expérimentaux démontrent que le curseur tangible déformable est globalement plus rapide de 14.3% que le curseur tangible classique sans que les résultats soient significativement différents. Alors que le curseur graphique o re de meilleures performances que les deux autres curseurs tangibles, le curseur tangible déformable o re une interac- tion sans regarder le dispositif avec une prise en main du dispositif stable.

International audience; Ultrasonic vibration is employed to modify the friction of a finger pad in way that induces haptic sensations. A combination of intermittent contact and squeeze film levitation has been previously proposed as the most probable mechanism. In this paper, in order to understand the underlying principles that govern friction modulation by intermittent contact, numerical models based on finite element (FE) analysis and also a spring-Coulombic slider are developed. The physical input parameters for the FE model are optimised by measuring the contact phase shift between a finger pad and a vibrating plate. The spring-slider model assists in the interpretation of the FE model and leads to the identification of a dimensionless group that allows the calculated coefficient of friction to be approximately superimposed onto an exponential function of the dimensionless group. Thus, it is possible to rationalise the computed relative reduction in friction being (i) dependent on the vibrational amplitude, frequency, and the intrinsic coefficient of friction of the device, and the reciprocal of the exploration velocity, and (ii) independent of the applied normal force, and the shear and extensional elastic moduli of the finger skin provided that intermittent contact is sufficiently well developed. Experimental validation of the modelling using real and artificial fingertips will be reported in part 2 of this work, which supports the current modelling.

The research field of fiber optical parametric amplifiers has steadily expanded over the last two decades as a host of all-optical signal processing techniques have been demonstrated in nonlinear optical fibers such as wavelength conversion, optical regeneration, optical switching, limiting, buffering, and sampling. This article reviews the system performances of theses parametric devices such as gain bandwidth, focuses on the main limitations and demonstrates efficient techniques for suppressing them. ∗ Arnaud Mussot is now with the Laboratoire de Physique des Lasers Atomes et Molecules, Universite des Sciences et Technologies de Lille, 59655 Villeneuve d'Asq cedex, France. † Armand Vedadi is now with the Institute of Advanced Telecommunications, Swansea University, Singleton Park Swansea SA2 8PP Wales, United Kingdom. ‡ Laurent Provino is now with PERFOS, 11 rue de Broglie, 22300 Lannion, France.

International audience; We address the problem of object modeling from 3D and 3D+T data made up of images which contain different parts of an object of interest, are separated by large spaces, and are misaligned with respect to each other. These images have only a limited number of intersections, hence making their registration particularly challenging. Furthermore, such data may result from various medical imaging modalities and can therefore present very diverse spatial configurations. Previous methods perform registration and object modeling (segmentation and interpolation) sequentially. However, sequential registration is ill-suited for the case of images with few intersections. We propose a new methodology which, regardless of the spatial configuration of the data, performs the three stages of registration, segmentation, and shape interpolation from spaced and misaligned images simultaneously. We integrate these three processes in a level set framework, in order to benefit from their synergistic interactions. We also propose a new registration method that exploits segmentation information rather than pixel intensities, and that accounts for the global shape of the object of interest, for increased robustness and accuracy. The accuracy of registration is compared against traditional mutual information based methods, and the total modeling framework is assessed against traditional sequential processing and validated on artificial, CT, and MRI data.

A dynamical uncertain system is studied in this paper. Two kinds of uncertainties are addressed, where the uncertain parameters are described through random variables and/or fuzzy variables. A general framework is proposed to deal with both kinds of uncertainty using a polynomial chaos expansion (PCE). It is shown that fuzzy variables may be expanded in terms of polynomial chaos when Legendre polynomials are used. The components of the PCE are a solution of an equation that does not depend on the nature of uncertainty. Once this equation is solved, the post-processing of the data gives the moments of the random response when the uncertainties are random or gives the response interval when the variables are fuzzy. With the PCE approach, it is also possible to deal with mixed uncertainty, when some parameters are random and others are fuzzy. The results provide a fuzzy description of the response statistical moments.

International audience; We present the concept of Emergeables - mobile surfaces that can deform or 'morph' to provide fully-actuated, tangible controls. Our goal in this work is to provide the flexibility of graphical touchscreens, coupled with the affordance and tactile benefits offered by physical widgets. In contrast to previous research in the area of deformable displays, our work focuses on continuous controls (e.g., dials or sliders), and strives for fully-dynamic positioning, providing versatile widgets that can change shape and location depending on the user's needs. We describe the design and implementation of two prototype emergeables built to demonstrate the concept, and present an in-depth evaluation that compares both with a touchscreen alternative. The results show the strong potential of emergeables for on-demand, eyes-free control of continuous parameters, particularly when comparing the accuracy and usability of a high-resolution emergeable to a standard GUI approach. We conclude with a discussion of the level of resolution that is necessary for future emergeables, and suggest how high-resolution versions might be achieved.

This paper investigates the fundamental nature of the polynomial chaos (PC) response of dynamic systems with uncertain parameters in the frequency domain. The eigenfrequencies of the extended matrix arising from a PC formulation govern the convergence of the dynamic response. It is shown that, in the particular case of uncertainties and with Hermite and Legendre polynomials, the PC eigenfrequencies are related to the roots of the underlying polynomials, which belong to the polynomial chaos set used to derive the polynomial chaos expansion. When Legendre polynomials are used, the PC eigenfrequencies remain in a bounded interval close to the deterministic eigenfrequencies because they are related to the roots of a Legendre polynomial. The higher the PC order, the higher the density of the PC eigenfrequencies close to the bounds of the interval, and this tends to smooth the frequency response quickly. In contrast, when Hermite polynomials are used, the PC eigenfrequencies spread from the deterministic eigenfrequencies (the highest roots of the Hermite polynomials tend to infinity when the order tends to infinity). Consequently, when the PC number increases, the smoothing effect becomes inefficient.

In this paper, we numerically investigate the fluorescence decay of Tm-doped tellurite glasses with different dopant concentrations. The aim is to find a set of data that allows the prediction of material performance over a wide range of doping concentrations. Among the available data, a deep investigation of the reverse cross-relaxation process (F,F,→H,H) was not yet available. The numerical simulation indicates that the reverse cross-relaxation process parameter can be calculated by fitting the slow decaying H fluorescence tails emitted when the pump level is almost depopulated. We also show that the floor of the H decay curve is indeed related to a second exponential constant, half the F lifetime, kicking in once the H level depopulates. By properly fitting the whole set of decay curves for all samples, the proposed value for the reverse cross-relaxation process is 0.03 times the cross-relaxation parameter. We also comment on the measurement accuracy and best set-up. Excellent agreement was found between the simulated and experimental data, indicating the validity of the approach. This paper therefore proposes a set of parameters validated by fitting experimental fluorescence decay curves of both the H and F levels. To the best of our knowledge, this is the first time a numerical simulation has been able to predict the fluorescence behavior of glasses with doping levels ranging from 0.36 mol% to 10 mol%. We also show that appropriate calculations of the reverse cross-relaxation parameter may have a significant effect on the simulation of laser and amplifier devices., This article is based upon work from H2020 COST Action MP1401 on “Fiber Lasers and Their Applications” supported by COST “(European Cooperation in Science and Technology)”. M. Ferrari acknowledges CNRS support, part of this research has been supported during his visit at UMR7010 INPHYNI - Institute de Physique de Nice.

International audience; Although this article presents a system and discusses its design, its content goes much further. In a sense, this paper is a position paper following 10 years of lessons learned working in graph visualization, developing new visualization techniques, and building systems for users. The strategy we have adopted is to develop, maintain, and improve the Tulip framework, aiming for an architecture with optimal data structure management from which target applications can be easily derived.

Part 1: Long and Short Papers (Continued); International audience; In this paper we introduce TicQR – a photo-based checkbox-enabled interface which bridges the physical and digital document domains, allowing automatic download or processing of useful data from paper documents. There is a long demonstrated need for people to be able to connect between printed material and digital information and services. By using a combination of image recognition and QR codes we are able to detect user marks on paper documents via a single photograph taken with a standard smart phone. This information can then be used to access the equivalent digital content, save contacts or URLs, or even order goods directly from local retailers.