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.

Traffic theory and the Internet

Abstract: We argue that traffic theory, an essential component in the design of traditional telecommunications networks, should be increasingly applied in the development of the multiservice Internet. We discuss the statistical characteristics of Internet traffic at different time scales. Modeling is facilitated on identifying the notion of flow and distinguishing the categories of streaming and elastic traffic. We review mathematical modeling approaches useful for predicting the relationship between demand, capacity and performance for both streaming and elastic flows. Derived results indicate the limitations of service differentiation as a means for guaranteeing QoS and highlight the importance of traditional traffic engineering approaches in ensuring that the network has sufficient capacity to handle offered demand.

Multidrug-resistant Klebsiella pneumoniae outbreak after endoscopic retrograde cholangiopancreatography

Abstract: Background and study aims Infection is a recognized complication of endoscopic retrograde cholangiopancreatography (ERCP). We describe the epidemiologic and molecular investigations of an outbreak of ERCP-related severe nosocomial infection due to KLEBSIELLA PNEUMONIAE producing extended-spectrum beta-lactamase (ESBL). Patients and methods We conducted epidemiologic and molecular investigations to identify the source of the outbreak in patients undergoing ERCP. We carried out reviews of the medical and endoscopic charts and microbiological data, practice audits, surveillance cultures of duodenoscopes and environmental sites, and molecular typing of clinical and environmental isolates. Results Between December 2008 and August 2009, 16 patients were identified post-ERCP with KLEBSIELLA PNEUMONIAE that produced extended-spectrum beta-lactamase type CTX-M-15. There were 8 bloodstream infections, 4 biliary tract infections, and 4 cases of fecal carriage. The microorganism was isolated only from patients who had undergone ERCP. Environmental investigations found no contamination of the washer-disinfectors or the surfaces of the endoscopy rooms. Routine surveillance cultures of endoscopes were repeatedly negative during the outbreak but the epidemic strain was finally isolated from one duodenoscope by flushing and brushing the channels. Molecular typing confirmed the identity of the clinical and environmental strains. Practice audits showed that manual cleaning and drying before storage were insufficient. Strict adherence to reprocessing procedures ended the outbreak. Conclusions The endoscopes used for ERCP can act as a reservoir for the emerging ESBL-producing K. PNEUMONIAE. Regular audits to ensure rigorous application of cleaning, high-level disinfection, and drying steps are crucial to avoid contamination.

Improved decoding with the SOVA in a parallel concatenated (Turbo-code) scheme

Abstract: We show that the soft output of the soft-output Viterbi-decoder (SOVA) suffers from two distortions. Firstly, for bad channels the reliability information of the decoder output is too optimistic. The output can be considered as being multiplied by a factor, that depends on the current bit-error-rate (BER). To become closer to the true log-likelihood ratio the output has to be normalized. Secondly, the soft-output of the SOVA-when used in Turbo decoding-is effected by a correlation between the so called extrinsic and intrinsic information. Since the extrinsic information is fed forward to be the a-priori information in the next decoding stage and is treated as being uncorrelated with the systematic-information, a correcting term has to be introduced in order to compensate this correlation. We show how these distortions can be corrected and we apply the correcting measures on the SOVA that is used as component decoder of a Turbo-code scheme. Finally, we provide simulation results that illustrate the gain due to normalizing the extrinsic information and exploiting the correlation in the soft output.

Designated verifier signatures: anonymity and efficient construction from any bilinear map

Abstract: The concept of Designated Verifier Signatures (DVS) was introduced by Jakobsson, Sako and Impagliazzo at Eurocrypt'96. These signatures are intended to a specific verifier, who is the only one able to check their validity. In this context, we formalize the notion of privacy of signer's identity which captures the strong designated verifier property investigated in their paper. We propose a variant of the pairing-based DVS scheme introduced at Asiacrypt'03 by Steinfeld, Bull, Wang and Pieprzyk. Contrary to their proposal, our new scheme can be used with any admissible bilinear map, especially with the low cost pairings and achieves the new anonymity property (in the random oracle model). Moreover, the unforgeability is tightly related to the Gap-Bilinear Diffie-Hellman assumption, in the random oracle model and the signature length is around 75% smaller than the original proposal.