Conservatoire national des arts et métiers

About: Conservatoire national des arts et métiers is a education organization based out in Paris, France. It is known for research contribution in the topics: Population & Orthogonal frequency-division multiplexing. The organization has 3573 authors who have published 7127 publications receiving 141430 citations. The organization is also known as: CNAM & Conservatoire des arts et métiers.

Personal control and coping with retail crowding

Abstract: To provide high quality services under conditions of crowding, it is important to understand the relationships between crowding and personal control. Indeed, in recent years, there has been growing belief that personal control is significant in coping with crowding. However, most studies have been of limited theoretical and practical value because they did not provide an integrated conceptualization of crowding. The results of a field study demonstrate that the personal control‐crowding relationships depend on the individual's crowding experience and the nature of personal control.

Evaluation of Non-Medical Costs Associated with Visual Impairment in Four European Countries

Abstract: Introduction Visual impairment is a severe disability that puts a heavy burden on individuals, families and society. In developed countries, the two major diseases leading to irreversible visual impairment are glaucoma and age-related macular degeneration. Their prevalence will increase dramatically with population aging. The economic consequences of visual impairment are considerable, but have rarely been documented, apart from some ‘top-down’ estimates based on national statistics. We estimated the non-medical costs related to visual impairment in four European countries: France, Italy, Germany and the UK.

Optimal Power Allocation for the Two-Way Relay Channel with Data Rate Fairness

Abstract: This letter studies data rate fairness on the two-way relay channel. It analytically determines the optimal power values at both nodes and at the relay, that lead to a maximization of the sum rate under the fairness constraint. Amplify-and-Forward (AF) and Decode-and-Forward (DF) relaying protocols are considered. For AF, the optimization problem is turned into a single-variable convex optimization problem. For DF, rate balancing between Multiple Access and broadcast phases must be performed prior to setting nodes powers. Both optimized protocols are compared with reference AF and DF in terms of data rates through numerical simulations.

Spatio-temporal data handling with constraints

Abstract: Most spatial information systems are limited to a fixed dimension (generally 2) which is not extensible. On the other hand, the emerging paradigm of constraint databases allows the representation of data of arbitrary dimension, together with abstract query languages. The complexity of evaluating queries though might be costly if the dimension of the objects is really arbitrary. In this paper, we present a data model, based on linear constraints, dedicated to the representation and manipulation of multidimensional data. In order to preserve a low complexity for query evaluation, we restrict the orthographic dimension of an object O, defined as the dimension of the components O1 ,..., On such that O=O1×...× On. This allows to process queries independently on each component, therefore achieving a satisfying trade-off between design simplicity, expressive power of the query language and efficiency of query evaluation. We illustrate these concepts in the context of spatio-temporal databases where space and time are the natural components. This data model has been implemented in the DEDALE system and a spatio-temporal application, with orthographic dimension 2, is currently running, thus showing the practical relevance of the approach.