A stochastic network with mobile users in heavy traffic

We consider a stochastic network with mobile users in a heavy-traffic regime. We derive the scaling limit of the multi-dimensional queue length process and prove a form of spatial state space collapse. The proof exploits a recent result by Lambert and Simatos which provides a general principle to establish scaling limits of regenerative processes based on the convergence of their excursions. We also prove weak convergence of the sequences of stationary joint queue length distributions and stationary sojourn times.Comment: Final version accepted for publication in Queueing Systems, Theory and Application

A Peer-reviewed Newspaper About_ Machine Research

About research on machines, research with machines, and research as a machine. Publication resulting from research workshop at Brussels World Trade Center, organised in collaboration with Constant, Association for Arts and Media, Brussels, and transmediale festival for art and digital culture, Berlin

Energy dependence of ϕ meson production at forward rapidity in pp collisions at the LHC

The production of $\phi$ mesons has been studied in pp collisions at LHC energies with the ALICE detector via the dimuon decay channel in the rapidity region $2.5< y < 4$. Measurements of the differential cross section $\mathrm{d}^2\sigma /\mathrm{d}y \mathrm{d}p_{\mathrm {T}}$ are presented as a function of the transverse momentum ($p_{\mathrm {T}}$) at the center-of-mass energies $\sqrt{s}=5.02$, 8 and 13 TeV and compared with the ALICE results at midrapidity. The differential cross sections at $\sqrt{s}=5.02$ and 13 TeV are also studied in several rapidity intervals as a function of $p_{\mathrm {T}}$, and as a function of rapidity in three $p_{\mathrm {T}}$ intervals. A hardening of the $p_{\mathrm {T}}$-differential cross section with the collision energy is observed, while, for a given energy, $p_{\mathrm {T}}$ spectra soften with increasing rapidity and, conversely, rapidity distributions get slightly narrower at increasing $p_{\mathrm {T}}$. The new results, complementing the published measurements at $\sqrt{s}=2.76$ and 7 TeV, allow one to establish the energy dependence of $\phi$ meson production and to compare the measured cross sections with phenomenological models. None of the considered models manages to describe the evolution of the cross section with $p_{\mathrm {T}}$ and rapidity at all the energies.publishedVersio

TDDFT Studies on sheet size-dependency of optoelectronic properties of 2d silicon

Silicene, a two-dimensional (2D) silicon nanosheet, has gained immense interest due to potential applications, better compatibility, and expected integration with current silicon (Si) technology. This work explores the effects of silicene sheet size on its optoelectronic properties using Time-Dependent Density Functional Theory (TDDFT). Four structures of hydrogen-terminated silicene, Si 13 H 22 , Si 19 H 30, Sis4H 74 , and Si l04 H 134 are investigated. It is observed that the structures have size tunable spectral response in the UV spectrum. The optimized sheets show a relatively smaller physical deformation compared to equivalent sized 2D Germanium sheets. IR spectra calculation of various bond vibrations show a good match with reported experimental results. The results show the potential for these 2D sheets to be effective optoelectronic materials in the visible spectrum, unlike bulk Si and Si nanowires. 2018 IEEE.Scopu

TDDFT Investigation of the hybrid organic inorganic perovskite: CH 3 NH 3 PbC 3

Hybrid organic-inorganic metal perovskites (chemical formula: ABX3, A-organic cation, B-metal ion, X-halide) are the latest advancement for increasing efficiency in thin-film solar cells or Dye Solar Cells (DSC). They have become the fastest growing technology in solar cells, rising in efficiency from 3% to 22.7% in less than a decade. This work focuses on a time-dependent density-functional theory (TDDFT) study of {CH 3 NH 3 PbCl 3 -methyl ammonium lead chloride- A perovskite material of potential and current research interest. The work focuses on the cubic phase. Electronic and optical properties including transition energy, band gap, and vibrational frequencies are examined. The Density of States (DOS) spectrum, IR and UV-VIS spectra are calculated. It is observed that the cubic phase of CH 3 }\text{NH}-{3}\text{PbCl}-{3}}$ shows responsivity for optical excitation between wavelength ranges from 180 nm to 350 nm, with the peak observed at 240 nm. This work will help significantly to understand charge transport and optical properties, and design optimized solar cells involving these materials. 2018 IEEE.Scopu