Orange S.A.

About: Orange S.A. is a company organization based out in Paris, France. It is known for research contribution in the topics: Terminal (electronics) & Signal. The organization has 6735 authors who have published 9190 publications receiving 156440 citations. The organization is also known as: Orange SA & France Télécom.

Cooperation in 4G - Hype or Ripe?

Abstract: With increasingly congested frequency bands and an ever-growing demand for higher data rates, innovative approaches are needed to increase the spectral efficiency and hence cost per bit/s/Hz overless links. Cooperative systems and radios, which are capable of intelligently forming mutually cooperative entities, are a promising way to achieve this increase in capacity. First technological and then social barriers, however, have prevented us so far from having technologies, systems, or users jointly cooperate. We will try to answer in this article whether the time is ripe for a technology which has recently received so much hype.

On the Typical Statistic Features for Image Blind Steganalysis

Abstract: Multimedia content is a suitable carrier for secret communication. This paper focuses on the steganalysis technique which aims to get the forensic of secrecy existing in multimedia carriers. A key concern for designing a blind steganalysis algorithm is the selection of statistic features. The Probability Density Function (PDF) moment and Characteristic Function (CF) moment are two typical kinds of statistic features commonly used in blind steganalysis. And generally, the features are computed from the subbands of transform domains, such as the wavelet coefficient subbands, the prediction subbands of wavelet coefficients, the prediction error subbands of wavelet coefficients, the wavelet coefficient subbands of image noise, and the log prediction error subbands of wavelet coefficients. To decide which feature is more sensitive to message embedding and useful for steganalysis is important and urgent. Till now, few works have focused on this topic, and they can only give some experimental results without theoretical analysis. Additionally, few frequency subbands have been investigated. To solve this problem, this paper reviews existing feature computing algorithms, compares the two kinds of features, the PDF moments and the CF moments, by analyzing the change trends of the statistic distribution parameters of various frequency subbands before and after message embedding, and so that provides a theoretical basis for the steganalysis feature selection and extraction. These theoretical results are further confirmed by experimental results. This is the first work to provide thorough theoretical analysis on so many feature computing algorithms. It is expected to provide valuable information to researchers or engineers working in the field of steganography forensics or steganalysis.

System for control of access to computer machines which are connected in a private network

Abstract: A system for control of access by messages to computer machines which are connected in a host private network by at least one private terminal that comprises an access control module interconnected at each input-output point of the host private network, each module allowing the selective transmission by inhibition, free or conditional authorization of the transmission of the messages to the host private network. A centralized supervisor module is associated with the host private network and interconnected by a specialized link to each access control module, allowing thus to control the selective transmission of the messages by each access control module.

Control of the polarization dependence of optically poled nonlinear polymer films.

Abstract: We demonstrate the possibility of controlling the symmetry properties of photoinduced χ2 macroscopic susceptibility in polymer films. Ellipsometric adjustment of the write beams allows one to monitor the macroscopic χ2 symmetry from a dipolar to an octupolar configuration. Experimental results are in agreement with an irreducible spherical tensor-based model jointly applied to the molecular β hyperpolarizability and field tensors. We found a purely octupolar polarization-independent photoinduced second-harmonic-generation response in a Dispersed Red 1–methyl methacrylate thin film. Such a configuration, as generated by an octupolar tensor write field tensor made up of counterclockwise circularly polarized ω and 2ω beams, is not within the reach of the classical electric-field poling technique.