Delay-aware Rate Adjusting Scheme in Higher Speed Passive Optical Networks

Flexible rate is a new desirable operational feature of next-generation higher speed passive optical networks (e.g., ITU-50G PON). In this context, this paper proposes a delay-aware rate adjusting scheme, in which the line rate can be adjusted following the traffic load varying to save energy without degrading delay performance. Simulation results show that the proposed scheme has a similar performance with the benchmark in the aspect of energy saving, while the delay performance of time-sensitive services can be improved significantly, which can be up to 36%

P-T-time-isotopic evolution of coesite-bearing eclogites: Implications for exhumation processes in SW Tianshan

International audienceThe Chinese Southwestern Tianshan high- to ultra-high pressure low temperature (HP–UHP/LT) metamorphic belt exhibits well-preserved mafic layers, tectonic blocks/slices and boudins of different sizes and lithology embedded within dominant meta-volcanosedimentary rocks. Despite a wealth of previous studies on UHP relicts, P–T path estimates and age constraints for metamorphism, controversies still exist on P–T–t assessments and regional exhumation patterns (i.e., tectonic mélange versus internally coherent “sub-belt” model). This study focuses on a group of coesite-bearing eclogite samples from a thick (~ 5 m) layered metabasalt outcrop in order to unravel its detailed tectono-metamorphic evolution through space and time (both prograde, peak and exhumation). Using SIMS zircon U–Pb and oxygen isotope analyses, TIMS Sm–Nd multi-point isochron dating, in situ laser-ICP-MS trace-element analyses, classical thermobarometry and thermodynamic modeling, we link the multistage zircon growth to garnet growth and reconstruct a detailed P–T–time-isotopic evolution history for this UHP tectonic slice: from UHP peak burial ~ 2.95 ± 0.2 GPa, 510 ± 20 °C around 318.0 ± 2.3 Ma to HP peak metamorphism ~ 2.45 ± 0.2 GPa, 540 ± 20 °C at 316.8 ± 0.8 Ma, then, with eclogite-facies deformation ~ 2.0 ± 0.15 GPa, 525 ± 25 °C at 312 ± 2.5 Ma, exhumed to near surface within ca. 303 to ca. 280 Ma. Our P–T-time-isotopic results combined with the compilation of regional radiometric data and P–T estimates notably point to the existence of a short-lived period of rock detachment and exhumation (< 10 Ma, i.e. at ca. 315 ± 5 Ma) with respect to subduction duration