A Queueing System for Modeling a File Sharing Principle

International audienceWe investigate in this paper the performance of a simple file sharing principle. For this purpose, we consider a system composed of N peers becoming active at exponential random times; the system is initiated with only one server offering the desired file and the other peers after becoming active try to download it. Once the file has been downloaded by a peer, this one immediately becomes a server. To investigate the transient behavior of this file sharing system, we study the instant when the system shifts from a congested state where all servers available are saturated by incoming demands to a state where a growing number of servers are idle. In spite of its apparent simplicity, this queueing model (with a random number of servers) turns out to be quite difficult to analyze. A formulation in terms of an urn and ball model is proposed and corresponding scaling results are derived. These asymptotic results are then compared against simulations

The P2P war: Someone is monitoring your activities

This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier’s archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/copyright Author's personal copy Available online at www.sciencedirect.co

Investment and the rate of profit in a financial context: the French case

The growth regime prevailing in France since the middle of the 1980s allowed for a recovery of profitability, yet without durable resumption of growth or accumulation of fixed capital. The financialization of this growth regime shows on both the asset and liability sides of the balance sheets. Following a post‐Keynesian framework, we analyse and test the main determinants of real investment and financial capital accumulation for non‐financial companies in France, based on data from the flow‐of‐funds accounts. This analysis points to an arbitrage, prevailing between real and financial accumulation, as a key reason explaining the insufficient recovery of investment.finance, investment, profit rate, growth regime, G11, E12, E22, C32,

Are there regional variations in the diagnosis surveillance, and control of methicillin-resistant Staphylococcus aureus?

OBJECTIVE: To assess the way healthcare facilities (HCFs) diagnose, survey, and control methicillin-resistant Staphylococcus aureus (MRSA). DESIGN: Questionnaire. SETTING: Ninety HCFs in 30 countries. RESULTS: Evaluation of susceptibility testing methods showed that 8 laboratories (9%) used oxacillin disks with antimicrobial content different from the one recommended, 12 (13%) did not determine MRSA susceptibility to vancomycin, and 4 (4.5%) reported instances of isolation of vancomycin-resistant S. aureus but neither confirmed this resistance nor alerted public health authorities. A MRSA control program was reported by 55 (61.1%) of the HCFs. The following isolation precautions were routinely used: hospitalization in a private room (34.4%), wearing of gloves (62.2%), wearing of gowns (44.4%), hand washing by healthcare workers (53.3%), use of an isolation sign on the patient's door (43%), or all four. When the characteristics of HCFs with low incidence rates (< 0.4 per 1,000 patient-days) were compared with those of HCFs with high incidence rates (≥ 0.4 per 1,000 patient-days), having a higher mean number of beds per infection control nurse was the only factor significantly associated with HCFs with high incidence rates (834 vs 318 beds; P = .02). CONCLUSION: Our results emphasize the urgent need to strengthen the microbiologic and epidemiologic capacities of HCFs worldwide to prevent MRSA transmission and to prepare them to address the possible emergence of vancomycin-resistant S. aureus.link_to_subscribed_fulltex

Are there regional variations in the diagnosis surveillance, and control of methicillin-resistant Staphylococcus aureus?

SCOPUS: ar.jinfo:eu-repo/semantics/publishe