Optimal sequential fingerprinting: Wald vs. Tardos

We study sequential collusion-resistant fingerprinting, where the fingerprinting code is generated in advance but accusations may be made between rounds, and show that in this setting both the dynamic Tardos scheme and schemes building upon Wald's sequential probability ratio test (SPRT) are asymptotically optimal. We further compare these two approaches to sequential fingerprinting, highlighting differences between the two schemes. Based on these differences, we argue that Wald's scheme should in general be preferred over the dynamic Tardos scheme, even though both schemes have their merits. As a side result, we derive an optimal sequential group testing method for the classical model, which can easily be generalized to different group testing models.Comment: 12 pages, 10 figure

Traffic noise in urban and regional roads and impact on the administrative facility P+30 in Prishtina

Many current problems are related to noise, which in many cases may be undesirable factorfor the daily activities and work conditions. This is especially evident in urban areas, where isa rapid growth of traffic including the number of vehicles, especially in peak time.Orientations and knowledge bases for the noise will take an important place in this paper,with the right understanding of this phenomenon.Till now in our country that is not taken into account in road and urban analyses. In this paperwe will orient the potential impact of noise in the administrative building in Pristina with P+30 floors, which is very close to the roundabout as a major source of noise. Such an outputdata, based on present measurements of the number of vehicles, made in a different specifiedperiod of time according to standards, and those elements will be interlinked with othergeometric and material parameters. All the analyses will show a result of the intensity of thenoise in dB. To analyze these parameters, intensity of the noise will be taken as the workloadof analyzed building. Also the result of unwanted intensity will be the factor for the designeddimensions and the calculation of the sound barriers in the roundabout, taking into accountthe incorporation in the environment and the urban planning of that part.The result will be presented as a 3D animation for this urban part and the impact of noise asan important factor, since we are dealing with a large concentration of administration in thisbuilding

Significant reduction of electronic correlations upon isovalent Ru substitution of BaFe2As2

We present a detailed investigation of Ba(Fe0.65Ru0.35)2As2 by transport measurements and Angle Resolved photoemission spectroscopy. We observe that Fe and Ru orbitals hybridize to form a coherent electronic structure and that Ru does not induce doping. The number of holes and electrons, deduced from the area of the Fermi Surface pockets, are both about twice larger than in BaFe2As2. The contribution of both carriers to the transport is evidenced by a change of sign of the Hall coefficient with decreasing temperature. Fermi velocities increase significantly with respect to BaFe2As2, suggesting a significant reduction of correlation effects. This may be a key to understand the appearance of superconductivity at the expense of magnetism in undoped iron pnictides

INHIBITIVE ACTION OF IMIDAZOLES FOR COPPER CORROSION IN SULFURIC ACID MEDIUM

The corrosion inhibition of copper in the presence of 10-3 M of imidazole derivatives; Imidazole (IM), 2-Methyle imidazole (MIM), Benzimidazole (BIM) has been investigated in 1.0 M H2SO4 solution using  potentiodynamic  polarization and electrochemical impedance spectroscopy (EIS). Relationship between molecular structure and their inhibition efficiency was elucidated by quantum chemical calculations using the density functional theory (DFT) at the B3LYP/6-31+G(d,p) level. Inhibition efficiency of these compounds which has been evaluated via experimental methods was accorded with reported theoretical ones, and following the same order as BIM ˃ MIM ˃ IM

Ultrafast filling of an electronic pseudogap in an incommensurate crystal

We investigate the quasiperiodic crystal (LaS)1.196(VS2) by angle and time resolved photoemission spectroscopy. The dispersion of electronic states is in qualitative agreement with band structure calculated for the VS2 slab without the incommensurate distortion. Nonetheless, the spectra display a temperature dependent pseudogap instead of quasiparticles crossing. The sudden photoexcitation at 50 K induces a partial filling of the electronic pseudogap within less than 80 fs. The electronic energy flows into the lattice modes on a comparable timescale. We attribute this surprisingly short timescale to a very strong electron-phonon coupling to the incommensurate distortion. This result sheds light on the electronic localization arising in aperiodic structures and quasicrystals

New electronic orderings observed in cobaltates under the influence of misfit periodicities

We study with ARPES the electronic structure of CoO2 slabs, stacked with rock-salt (RS) layers exhibiting a different (misfit) periodicity. Fermi Surfaces (FS) in phases with different doping and/or periodicities reveal the influence of the RS potential on the electronic structure. We show that these RS potentials are well ordered, even in incommensurate phases, where STM images reveal broad stripes with width as large as 80\AA. The anomalous evolution of the FS area at low dopings is consistent with the localization of a fraction of the electrons. We propose that this is a new form of electronic ordering, induced by the potential of the stacked layers (RS or Na in NaxCoO2) when the FS becomes smaller than the Brillouin Zone of the stacked structure

Silicon intercalation into the graphene-SiC interface

In this work we use LEEM, XPEEM and XPS to study how the excess Si at the graphene-vacuum interface reorders itself at high temperatures. We show that silicon deposited at room temperature onto multilayer graphene films grown on the SiC(000[`1]) rapidly diffuses to the graphene-SiC interface when heated to temperatures above 1020. In a sequence of depositions, we have been able to intercalate ~ 6 ML of Si into the graphene-SiC interface.Comment: 6 pages, 8 figures, submitted to PR