1,091 research outputs found

    Tolerance analysis approach based on the classification of uncertainty (aleatory / epistemic)

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    Uncertainty is ubiquitous in tolerance analysis problem. This paper deals with tolerance analysis formulation, more particularly, with the uncertainty which is necessary to take into account into the foundation of this formulation. It presents: a brief view of the uncertainty classification: Aleatory uncertainty comes from the inherent uncertain nature and phenomena, and epistemic uncertainty comes from the lack of knowledge, a formulation of the tolerance analysis problem based on this classification, its development: Aleatory uncertainty is modeled by probability distributions while epistemic uncertainty is modeled by intervals; Monte Carlo simulation is employed for probabilistic analysis while nonlinear optimization is used for interval analysis.“AHTOLA” project (ANR-11- MONU-013

    Scheduling Policies in Time and Frequency Domains for LTE Downlink Channel: A Performance Comparison

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    A key feature of the Long-Term Evolution (LTE) system is that the packet scheduler can make use of the channel quality information (CQI), which is periodically reported by user equipment either in an aggregate form for the whole downlink channel or distinguished for each available subchannel. This mechanism allows for wide discretion in resource allocation, thus promoting the flourishing of several scheduling algorithms, with different purposes. It is therefore of great interest to compare the performance of such algorithms under different scenarios. Here, we carry out a thorough performance analysis of different scheduling algorithms for saturated User Datagram Protocol (UDP) and Transmission Control Protocol (TCP) traffic sources, as well as consider both the time- and frequency-domain versions of the schedulers and for both flat and frequency-selective channels. The analysis makes it possible to appreciate the difference among the scheduling algorithms and to assess the performance gain, in terms of cell capacity, users' fairness, and packet service time, obtained by exploiting the richer, but heavier, information carried by subchannel CQI. An important part of this analysis is a throughput guarantee scheduler, which we propose in this paper. The analysis reveals that the proposed scheduler provides a good tradeoff between cell capacity and fairness both for TCP and UDP traffic sources

    Iraq today: The failure of re-shaping a state on sectarian and quota lines.

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    By Professor Saad N Jawad Senior Research Fellow at the Middle East Centre, LSE & Dr Sawsan I al-Assaf Board Member of the Peace Building-Academy for the Middle East, Spain & Beirut

    Cloud Point Extraction Methodology for Separation and Extraction Platinum (II) as Chloro Complex Anion Coupled with Spectrophotometric Method for Determination in Different Samples

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    Whereas the platinum is very important metal with several special properties to provide it as expensive metal with important using , for separation preconcentration and extraction platinum as Chloroanion PtCl4= according to cloud point extraction method used Triton X-100 at optimum conditions such as 1M HCl with 1x10-4M Janus green (JG) and 0.5 mL of 1%  Triton X-100 Cloud point layer Formation at 75?C of heating in electrostatic water bath for 15 minutes , The stoichiometric study show the more probable structure of ion association Complex extraction was [JG+ ; HPtCl4-] , with thermodynamic data ?Hex = 0.0814KJ mol-1 , ?Gex =-61.42 KJ mol-1 and ?Sex = 176.7J mol-1 K-1, the main method for extraction show D.L = 6.8028*10-6 S=0.003133 µg cm-1 R.S.D= 0.00885                               the maximum absorbance wave length was = 690 nm  and ?= 6227.861 L mol-1 cm-1 Keywords: platinum, cloud point extractio

    A systematic review identifying common data items in neonatal trials and assessing their completeness in routinely recorded United Kingdom national neonatal data

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    Background We aimed to test whether a common set of key data items reported across high impact neonatal clinical trials could be identified, and to quantify their completeness in routinely recorded United Kingdom neonatal data held in the National Neonatal Research Database (NNRD). Methods We systematically reviewed neonatal clinical trials published in four high impact medical journals over 10 years (2006-2015) and extracted baseline characteristics, stratification items, and potential confounders used to adjust primary outcomes. Completeness was examined using data held in the NNRD for identified data items, for infants admitted to neonatal units in 2015. The NNRD is a repository of routinely recorded data extracted from neonatal Electronic Patient Records (EPR) of all admissions to National Health Service (NHS) Neonatal Units in England, Wales and Scotland. We defined missing data as an empty field or an implausible value. We reported common data items as frequencies and percentages alongside percentages of completeness. Results We identified 44 studies involving 32,095 infants and 126 data items. Fourteen data items were reported by more than 20% of studies (table 2). Gestational age (95%), sex (93%) and birth weight (91%) were the most common baseline data items. The completeness of data in the NNRD was high for these data with greater than 90% completeness found for 9 of the 14 most common items. Conclusion High impact neonatal clinical trials share common data items. In the United Kingdom, these items can be obtained at a high level of completeness from routinely recorded data held in the NNRD. The feasibility and efficiency using routinely recorded EPR data, such as that held in the NNRD, for clinical trials, rather than collecting these items anew, should be examined

    Correlation between TcT_c and anisotropic scattering in Tl2_2Ba2_2CuO6+δ_{6+\delta}

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    Angle-dependent magnetoresistance measurements are used to determine the isotropic and anisotropic components of the transport scattering rate in overdoped Tl2_2Ba2_2CuO6+δ_{6+\delta} for a range of TcT_c values between 15K and 35K. The size of the anisotropic scattering term is found to scale linearly with TcT_c, establishing a link between the superconducting and normal state physics. Comparison with results from angle resolved photoemission spectroscopy indicates that the transport and quasiparticle lifetimes are distinct.Comment: 5 pages, 3 figures, accepted for publication in Physical Review Letter
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