Recommendations for the representation of hierarchical objects in Europeana

The issue of handling hierarchical objects has been always an important topic for Europeana’s network of projects and Data Providers. The implementation of solutions in the Europeana portal has been delayed for a long time mainly due to the fact that complex objects required the development of new functionalities that could not be supported by the Europeana Semantic Elements (ESE) model. Indeed the simplicity and the flatness of this model prevented Data Providers from supplying complex objects

Costly banknote issuance and interest rates under the national banking system

The behavior of interest rates under the U.S. National Banking System is puzzling because of the apparent presence of persistent and large unexploited arbitrage opportunities for note issuing banks. Previous attempts to explain interest rate behavior have relied on the cost or the inelasticity of note issue. These attempts are not entirely satisfactory. Here we propose a new rationale to solve the puzzle. Inelastic note issuance arises endogenously because the marginal cost of issuing notes is an increasing function of circulation. We build a spatial separation model where some fraction of agents must move each period. Banknotes can be carried between locations; deposits cannot. Taking the model to the data on national banks, we find it matches the movements in long-term interest rates well. It also predicts movements in deposit rates during panics. However, the model displays more inelasticity of notes issuance than is in the data.Bank notes ; Interest rates ; National banks (United States)

Numerical simulation round robin of a coupled volume case: Preliminary results

International audienceThe advantages and limitations of most numerical methods in room acoustics have to date been primarily evaluated in single-volume room conditions, placing emphasis on early reflection components and the early part of the room acoustic impulse response. Few studies have examined the capabilities of simulations to model correctly the case of coupled volumes, where the late part of the impulse response is not a simple extension of the early part and needs to be accurately represented. This work presents preliminary results of a round robin study comparing numerical simulation results with coupled volume theory, using physical scale model measurements to define general parameters. Numerical methods included geometrical acoustic solutions, with image source method and ray/cone/path-tracing type approaches, and wave-based methods, comprising several FDTD implementations. A scale model was used to set the parameters of a statistical model to ensure a physically realistic configuration. Room model coordinates were specified. To avoid issues regarding variations in implementation of material and scattering behaviors across methods, the reverberation time of separate individual volumes was prescribed in the uncoupled condition. Volumes were then coupled and the results analyzed. The comparison is of a rather simplified room acoustic model, assuming homogeneous boundary conditions

Topologically protected edge states in small Rydberg systems

We propose a simple setup of Rydberg atoms in a honeycomb lattice which gives rise to topologically protected edge states. The proposal is based on the combination of dipolar exchange interaction, which couples the internal angular momentum and the orbital degree of freedom of a Rydberg excitation, and a static magnetic field breaking time reversal symmetry. We demonstrate that for realistic experimental parameters, signatures of topologically protected edge states are present in small systems with as few as 10 atoms. Our analysis paves the way for the experimental realization of Rydberg systems characterized by a topological invariant, providing a promising setup for future application in quantum information.Comment: 6 pages, 6 figure

Espace et rapports de domination

International audienceDégagée de la plupart de ses contrepouvoirs depuis la fin des années 1980, le projet politique néolibéral et les inégalités qu’il renforce paraissent aujourd’hui sans remède. Est-il si difficile de ne pas céder à la résignation ou, pire, à l’indifférence ? Les outils pour identifier ces inégalités, les expliquer et les dénoncer ne manquent pas. La pensée critique connaît, en France comme ailleurs, un formidable renouveau. Dans toutes les disciplines des sciences sociales, l’apport de nos aînés est revisité et enrichi de nouvelles propositions pour se confronter aux injustices contemporaines, qui semblent rendues acceptables par des manipulations intellectuelles et des ficelles de plus en plus grossières.L’espace est, comme le temps et l’argent, un redoutable allié des dominants. Accaparé, exproprié, spolié, marchandisé, financiarisé, surveillé, refusé, l’espace se révèle être, à toutes les échelles et dans toutes ses configurations, une excellente clef de lecture de la situation des dominés. Confinement, relégation, enfermement en sont les modalités extrêmes, mais bien d’autres, plus subtiles et moins visibles, contribuent à pérenniser des rapports de force à ce point asymétriques qu’il n’est de meilleur terme pour les qualifier que celui de domination. Mais l’espace est aussi l’allié des dominés engagés dans des processus de résistance, de contestation ou de lutte contre l’ordre du capitalisme néolibéral. Dotés de ressources propres, les dominés construisent aussi des stratégies, individuelles ou collectives, qui prennent appui dans l’espace et peuvent faire de ce dernier une ressource pour se faire entendre ou se rendre visible.Dans un contexte académique mondial dominé par les travaux anglophones, en particulier ceux de la géographie radicale, cet ouvrage entend présenter la manière dont les chercheurs et chercheuses francophones travaillant sur les questions spatiales analysent les rapports sociaux de domination, qu’ils soient de classe, de race, de sexe, autant de rapports sociaux qui ont un fondement matériel. Plusieurs entrées thématiques sont explorées, qui renvoient à des champs de recherche bien identifiés : la question urbaine, les études sur le genre, le sexe, la sexualité et l’intersectionnalité, la question des migrations et celle des populations marginalisées et, enfin, l’environnement. Cet ouvrage témoigne donc de la grande vivacité des travaux francophones, tout en réaffirmant l’utilité de penser l’espace dans la critique sociale

Hand-worn Haptic Interface for Drone Teleoperation

Drone teleoperation is usually accomplished using remote radio controllers, devices that can be hard to master for inexperienced users. Moreover, the limited amount of information fed back to the user about the robot's state, often limited to vision, can represent a bottleneck for operation in several conditions. In this work, we present a wearable interface for drone teleoperation and its evaluation through a user study. The two main features of the proposed system are a data glove to allow the user to control the drone trajectory by hand motion and a haptic system used to augment their awareness of the environment surrounding the robot. This interface can be employed for the operation of robotic systems in line of sight (LoS) by inexperienced operators and allows them to safely perform tasks common in inspection and search-and-rescue missions such as approaching walls and crossing narrow passages with limited visibility conditions. In addition to the design and implementation of the wearable interface, we performed a systematic study to assess the effectiveness of the system through three user studies (n = 36) to evaluate the users' learning path and their ability to perform tasks with limited visibility. We validated our ideas in both a simulated and a real-world environment. Our results demonstrate that the proposed system can improve teleoperation performance in different cases compared to standard remote controllers, making it a viable alternative to standard Human-Robot Interfaces.Comment: Accepted at the IEEE International Conference on Robotics and Automation (ICRA) 202

Tree leaves extraction in natural images: Comparative study of pre-processing tools and segmentation methods

International audienceIn this paper, we propose a comparative study of various segmentation methods applied to the extraction of tree leaves from natural images. This study follows the design of a mobile application, developed by Cerutti et al. (published in ReVeS Participation-Tree Species Classification Using Random Forests and Botanical Features. CLEF 2012), to highlight the impact of the choices made for segmentation aspects. All the tests are based on a database of 232 images of tree leaves depicted on natural background from smartphones acquisitions. We also propose to study the improvements, in terms of performance, by using pre-processing tools such as the interaction between the user and the application through an input stroke, as well as the use of color distance maps. The results presented in this paper shows that the method developed by Cerutti et al. (denoted Guided Active Contour), obtains the best score for almost all observation criteria. Finally we detail our online benchmark composed of 14 unsupervised methods and 6 supervised ones

Linearly bounded infinite graphs

Linearly bounded Turing machines have been mainly studied as acceptors for context-sensitive languages. We define a natural class of infinite automata representing their observable computational behavior, called linearly bounded graphs. These automata naturally accept the same languages as the linearly bounded machines defining them. We present some of their structural properties as well as alternative characterizations in terms of rewriting systems and context-sensitive transductions. Finally, we compare these graphs to rational graphs, which are another class of automata accepting the context-sensitive languages, and prove that in the bounded-degree case, rational graphs are a strict sub-class of linearly bounded graphs

Selective solar photodegradation of organopollutant mixtures in water

Abstract Heterogeneous photocatalysis in a water solution is recognised as a method of totally eliminating most recalcitrant organic pollutants found in such solutions. Our current work has tried to show that the heterogeneous photocatalysis process can also be a selective elimination method in the case of the mixture: 4-hydroxybenzoic acid (4-HBz) and benzamide (Bz) at semi-pilot plant scale (190 dm 3 ) under conditions of solar irradiation. The photocatalysis experiments performed by us were done at the ''Plataforma Solar de Almer ıa'' and were carried out in the compound parabolic collectors' CPC system. We investigated in particular the influence of TiO 2 loading, the effect of 4-HBz concentration and the effect of the presence of chloride anions and pH on the selectivity of the reaction process

InSight: Single Station Broadband Seismology for Probing Mars' Interior

InSight is a proposed Discovery mission which will deliver a lander containing geophysical instrumentation, including a heat flow probe and a seismometer package, to Mars. The aim of this mission is to perform, for the first time, an in-situ investigation of the interior of a truly Earth- like planet other than our own, with the goal of understanding the formation and evolution of terrestrial planets through investigation of the interior structure and processes of Mars