Full-Service MAC Protocol for Metro-Reach GPONs

“This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder." “Copyright IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.”An advanced medium access control protocol is presented demonstrating dynamic bandwidth allocation for long-reach gigabit-capable passive optical networks (GPONs). The protocol enables the optical line terminal to overlap the idle time slots in each packet transmission cycle with a virtual polling cycle to increase the effective transmission bandwidth. Contrasting the new scheme with developed algorithms, network modeling has exhibited significant improvement in channel throughput, mean packet delay, and packet loss rate in the presence of class-of-service and service-level differentiation. In particular, the displayed 34% increase in the overall channel throughput and 30 times reduction in mean packet delay for service-level 1 and service-level 2 optical network units (ONUs) at accustomed 50% ONU load constitutes the highest extended-reach GPON performance reported up to date.Peer reviewe

Vibrational Analysis Of Amorphous Carbon-nitrogen Alloys By 15n And D Isotopic Substitution

The origin of the vibrational modes of a-CNx alloys is investigated by infrared (ir) and Raman spectroscopies. Isotopic substitution of 15N and D is used in the identification of vibration modes. In nonhydrogenated materials containing low nitrogen concentration (≤20 at. %), the ir and Raman spectra are not equivalent. Above this concentration (up to ∼30 at. %), the spectra became very similar to each other. On the contrary, for a suitable hydrogen content the spectra are quite similar, independently of the range of nitrogen concentrations studied. Quantum chemical Parametric Method 3 calculations are performed to obtain the frequencies and intensities of the ir active vibrations of organic molecules and large carbon-nitrogen clusters. These results are used to help in the identification of the features observed in the ir spectra. The importance of both the promotion of bond dipoles and symmetry breaking by nitrogen in the ir spectra is established. ©2000 The American Physical Society.61210831087Fang, P.H., (1995) J. Mater. Sci. Lett., 14, p. 536Franceschini, D.F., Achete, C.A., Freire Jr., F.I., (1992) Appl. Phys. Lett., 60, p. 3229Jones, D.I., Stewart, A.D., (1982) Philos. Mag. B, 46, p. 423Chen, L.C., Lu, T.R., Cuo, C.T., Bhusari, D.M., Wu, J.J., Chen, K.H., Chen, T.M., (1998) Appl. Phys. Lett., 72, p. 3449Liu, A., Cohen, L., (1989) Science, 245, p. 841Kaufman, J.H., Metin, S., Saperstein, D.D., (1989) Phys. Rev. B, 39, p. 13053Souto, S., Alvarez, F., (1997) Appl. Phys. Lett., 70, p. 1539Hammer, P., Victoria, N.M., Alvarez, F., (1998) J. Vac. Sci. Technol. A, 16, p. 2941Alvarez, F., Victoria, N.M., Hammer, P., Freire Jr., F.L., Dos Santos, M.C., (1998) Appl. Phys. Lett., 73, p. 1065Alvarez, F., Dos Santos, M.C., Hammer, P., (1998) Appl. Phys. Lett., 73, p. 3521Souto, S., Pickholz, M., Dos Santos, M.C., Alvarez, F., (1998) Phys. Rev. B, 57, p. 2536Dos Santos, M.C., Alvarez, F., (1998) Phys. Rev. B, 58, p. 13918Stewart, J.J.P., (1989) J. Comput. Chem., 10, p. 209(1995) SPARTAN, Package V. 5, , Wavefunction, Inc(1996) HYPERCHEM, Version 5, , Hypercube, IncLey, L., (1984) Topics in Applied Physics, 56. , The Physics of Hydrogenated Amorphous Silicon II, edited by J. D. Joannopoulos and G. Lucousky, Springer-Verlag, BerlinSubramanian, V., Chitra, K., Venkatesh, K., Sanker, S., Ramasami, T., (1997) Chem. Phys. Lett., 264, p. 92Shinohara, Y., Saito, R., Kimura, T., Dresselhaus, G., Dresselhaus, M.S., (1994) Chem. Phys. Lett., 227, p. 365Borisenko, V.E., Baturin, A.V., Przeslawka, M., Koll, A., (1997) J. Mol. Struct., 407, p. 53Robertson, J., (1991) Prog. Solid State Chem., 21, p. 19

The Moduli Space of BPS Domain Walls

N=2 SQED with several flavors admits multiple, static BPS domain wall solutions. We determine the explicit two-kink metric and examine the dynamics of colliding domain walls. The multi-kink metric has a toric Kahler structure and we reduce the Kahler potential to quadrature. In the second part of this paper, we consider semi-local vortices compactified on circle. We argue that, in the presence of a suitable Wilson line, the vortices separate into domain wall constituents. These play the role of fractional instantons in two-dimensional gauge theories and sigma-models.Comment: 16 pages, LaTex, 2 figures; factors of zeta corrected, meaning of cross-terms elucidated, further clarifying comments; (more) references adde

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02

Early carboniferous brachiopod faunas from the Baoshan block, west Yunnan, southwest China

38 brachiopod species in 27 genera and subgenera are described from the Yudong Formation in the Shidian-Baoshan area, west Yunnan, southwest China. New taxa include two new subgenera: Unispirifer (Septimispirifer) and Brachythyrina (Longathyrina), and seven new species: Eomarginifera yunnanensis, Marginatia cylindrica, Unispirifer (Unispirifer) xiangshanensis, Unispirifer (Septimispirifer) wafangjieensis, Brachythyrina (Brachythyrina) transversa, Brachythyrina (Longathyrina) baoshanensis, and Girtyella wafangjieensis. Based on the described material and constraints from associated coral and conodont faunas, the age of the brachiopod fauna from the Yudon Formation is considered late Tournaisian (Early Carboniferous), with a possibility extending into earlyViseacutean.<br /