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.

Dynamic location area management and performance analysis

Abstract: A dynamic location area scheme is proposed for cellular networks, in which the size of location areas of a user is dynamically determined according to its current incoming call arrival rate and mobility as the signaling traffic in radio channels reaches the minimum. The protocols and algorithms of the proposed scheme are presented, and its performance is compared with that of the conventional system.

Analysis of noise reduction and dereverberation techniques based on microphone arrays with postfiltering

Abstract: In teleconferencing systems, the use of hands-free sound pick-up reduces speech quality. This is due to ambient noise, acoustic echo, and the reverberation produced by the acoustical environment. This paper sets out to present a theoretical analysis of noise reduction and dereverberation algorithms based on a microphone array combined with a Wiener postfilter. It is shown that the transfer function of the postfilter depends on the input signal-to-noise ratio (SNR) and on the noise reduction yielded by the array. The use of a directivity-controlled array instead of a conventional beam-former is proposed to improve the performance of the whole system. Examples in real room environments are provided, which confirm the theoretical results, It is observed that the postfilter gives a limited reduction of the reverberation. On the contrary, an appreciable reduction of acoustic echo and localized noise is obtained and makes the whole system highly attractive for hands-free communication systems.

GPS: location-tracking technology

Abstract: Increasing commercial use of the Global Positioning System will soon make it possible to locate anything, anywhere, anytime. The Global Positioning System can provide extremely accurate location information for mobile objects and people which is far superior to earlier tracking techniques. The challenge today is integrating the necessary components into older systems and improving GPS accuracy in areas with numerous obstructions. As more devices become GPS enabled, accuracy will increase and the system's scale and global reach will benefit everyone. Wireless technology promises to be a key element in any long-term solution.

On automating Web services discovery

Abstract: One of the challenging problems that Web service technology faces is the ability to effectively discover services based on their capabilities. We present an approach to tackling this problem in the context of description logics (DLs). We formalize service discovery as a new instance of the problem of rewriting concepts using terminologies. We call this new instance the best covering problem. We provide a formalization of the best covering problem in the framework of DL-based ontologies and propose a hypergraph-based algorithm to effectively compute best covers of a given request. We propose a novel matchmaking algorithm that takes as input a service request (or query) Q and an ontology $\mathcal{T}$ of services and finds a set of services called a “best cover” of Q whose descriptions contain as much common information with Q as possible and as little extra information with respect to Q as possible. We have implemented the proposed discovery technique and used the developed prototype in the context of the Multilingual Knowledge Based European Electronic Marketplace (MKBEEM) project.

Active attack against HB+: a provably secure lightweight authentication protocol

Abstract: Much research has focused on providing RFID tags with lightweight cryptographic functionality. The HB+ authentication protocol was recently proposed and claimed to be secure against both passive and active attacks. A linear-time active attack against HB+ is proposed.