Dynamics underlying Box-office: Movie Competition on Recommender Systems

We introduce a simple model to study movie competition in the recommender systems. Movies of heterogeneous quality compete against each other through viewers' reviews and generate interesting dynamics of box-office. By assuming mean-field interactions between the competing movies, we show that run-away effect of popularity spreading is triggered by defeating the average review score, leading to hits in box-office. The average review score thus characterizes the critical movie quality necessary for transition from box-office bombs to blockbusters. The major factors affecting the critical review score are examined. By iterating the mean-field dynamical equations, we obtain qualitative agreements with simulations and real systems in the dynamical forms of box-office, revealing the significant role of competition in understanding box-office dynamics.Comment: 8 pages, 6 figure

Anisotropic Laplace-Beltrami Operators for Shape Analysis

International audienceThis paper introduces an anisotropic Laplace-Beltrami operator for shape analysis. While keeping useful properties of the standard Laplace-Beltrami operator, it introduces variability in the directions of principal curvature, giving rise to a more intuitive and semantically meaningful diffusion process. Although the benefits of anisotropic diffusion have already been noted in the area of mesh processing (e.g. surface regularization), focusing on the Laplacian itself, rather than on the diffusion process it induces, opens the possibility to effectively replace the omnipresent Laplace-Beltrami operator in many shape analysis methods. After providing a mathematical formulation and analysis of this new operator, we derive a practical implementation on discrete meshes. Further, we demonstrate the effectiveness of our new operator when employed in conjunction with different methods for shape segmentation and matching

Combining spatial support information and shape-based method for tomographic imaging inside a microwave cylindrical scanner

International audienceA nonlinear inverse scattering problem is solved to retrieve the permittivity maps inside a microwave cylindrical scanner of circular cross-section. In this article, we show how we can improve this minimization scheme by taking advantage of several a priori pieces of information. In particular, a global representation based on a Zernike basis expansion is introduced in order to restrain the class of solutions to functions which have circular spatial support, as is the case with the encountered geometrical configuration. The level-set function formalism is also exploited as the targets are known to be homogeneous by parts. We will show how we can combine the spatial support information and the binary nature of the scatterer, with limited changes of the inversion algorithm. Both synthetic and experimental results will be presented in order to highlight the importance of combining all the pieces of available information

Brewster quasi bound states in the continuum in all-dielectric metasurfaces from single magnetic-dipole resonance meta-atoms

Bound states in the continuum (BICs) are ubiquitous in many areas of physics, attracting especial interest for their ability to confine waves with infinite lifetimes. Metasurfaces provide a suitable platform to realize them in photonics; such BICs are remarkably robust, being however complex to tune in frequency-wavevector space.Here we propose a scheme to engineer BICs and quasi-BICs with single magnetic-dipole resonance meta-atoms. Upon changing the orientation of the magnetic-dipole resonances, we show that the resulting quasi-BICs,emerging from the symmetry-protected BIC at normal incidence, become transparent for plane-wave illumination exactly at the magnetic-dipole angle, due to a Brewster-like effect. While yielding infinite Q-factors at normalincidence(canonical BIC), these are termed Brewster quasi-BICs since a transmission channel is always allowed that slightly widens resonances at oblique incidences. This is demonstrated experimentally through reflectance measurements in the microwave regime with high-refractive-index mm-disk metasurfaces. Such Brewster-inspired configuration is a plausible scenario to achieve quasi-BICs throughout the electromagnetic spectrum inaccessible through plane-wave illumination at given angles, which could be extrapolated to other kind of waves.Comment: 15 pages, 7 figures; typos corrected, Figs. 3 & 5 modified, new Fig. 7 & references adde

Measures for explainable AI: Explanation goodness, user satisfaction, mental models, curiosity, trust, and human-AI performance

If a user is presented an AI system that portends to explain how it works, how do we know whether the explanation works and the user has achieved a pragmatic understanding of the AI? This question entails some key concepts of measurement such as explanation goodness and trust. We present methods for enabling developers and researchers to: (1) Assess the a priori goodness of explanations, (2) Assess users\u27 satisfaction with explanations, (3) Reveal user\u27s mental model of an AI system, (4) Assess user\u27s curiosity or need for explanations, (5) Assess whether the user\u27s trust and reliance on the AI are appropriate, and finally, (6) Assess how the human-XAI work system performs. The methods we present derive from our integration of extensive research literatures and our own psychometric evaluations. We point to the previous research that led to the measurement scales which we aggregated and tailored specifically for the XAI context. Scales are presented in sufficient detail to enable their use by XAI researchers. For Mental Model assessment and Work System Performance, XAI researchers have choices. We point to a number of methods, expressed in terms of methods\u27 strengths and weaknesses, and pertinent measurement issues

Ethnophenomenological Influence and Levels of Psychological Differentiation

The purpose of this study was to investigate the relative levels of psychological differentiation in Jewish and Protestant children

A multi-dimensional view of transport-related social exclusion: A comparative study of Greater Perth and Sydney

Transport-related social exclusion is a complex issue. It can be studied from a variety of angles, be influenced by a number of factors, and affect diverse population groups. This study investigates transport-related social exclusion from a multi-dimensional view. Transport inequity was measured based on different development stages of a region using the Lorenz Curve and Gini index, and compared socio-economic characteristics, such as housing affordability, employment self-sufficiency, urban sprawl, and transport-mode share at different degrees of spatial aggregation. Two hierarchical spatial aggregation levels are used: (1) Sydney – Perth; (2) Inner – Middle – Outer sectors. Spatial gaps of transport-related social exclusion are identified for both cities and a number of policy implications are considered to provide suggestions to improve transport-related social inclusion in both cities

An architecture for the design of context-aware conversational agents

Proceedings of: 8th International Conference on Practical Applications of Agents and Multiagent Systems, Salamanca, Spain, April 26-28, 2010.In this paper, we present a architecture for the development of conversational agents that provide a personalized service to the user. The different agents included in our architecture facilitate an adapted service by taking into account context information and users specific requirements and preferences. This functionality is achieved by means of the introduction of a context manager and the definition of user profiles. We describe the main characteristics of our architecture and its application to develop and evaluate an information system for an academic domain.CICYT TIN2008-06742-C02-02/TSI, CICYT TEC2008-06732-C02- 02/TEC, SINPROB, CAM MADRINET S-0505/TIC/0255 and DPS2008-07029-C02-02.Publicad