Parametric timed model checking for guaranteeing timed opacity

Information leakage can have dramatic consequences on systems security. Among harmful information leaks, the timing information leakage is the ability for an attacker to deduce internal information depending on the system execution time. We address the following problem: given a timed system, synthesize the execution times for which one cannot deduce whether the system performed some secret behavior. We solve this problem in the setting of timed automata (TAs). We first provide a general solution, and then extend the problem to parametric TAs, by synthesizing internal timings making the TA secure. We study decidability, devise algorithms, and show that our method can also apply to program analysis.Comment: This is the author (and extended) version of the manuscript of the same name published in the proceedings of ATVA 2019. This work is partially supported by the ANR national research program PACS (ANR-14-CE28-0002), the ANR-NRF research program (ProMiS) and by ERATO HASUO Metamathematics for Systems Design Project (No. JPMJER1603), JS

Long Range Hydration Effects in Electrolytic Free Suspended Black Films

The force law within free suspended black films made of negatively charged Aerosol-OT (AOT) with added LiCl or CsCl is studied accurately using X-ray reflectivity (ca. 1{\AA}). We find an electrolyte concentration threshold above which a substantial additional repulsion is detected in the LiCl films, up to distances of 100 {\AA}. We interpret this phenomenon as an augmentation of the Debye screening length, due to the local screening of the condensed hydrophilic counterions by the primary hydration shell.Comment: 4 pages, 4 figures, to be published Phys. Rev. Let

Magnetic reconnection driven by electron dynamics

Magnetic reconnections play essential roles in space, astrophysical, and laboratory plasmas, where the anti-parallel magnetic field components re-connect and the magnetic energy is converted to the plasma energy as Alfvénic out flows. Although the electron dynamics is considered to be essential, it is highly challenging to observe electron scale reconnections. Here we show the experimental results on an electron scale reconnection driven by the electron dynamics in laser-produced plasmas. We apply a weak-external magnetic field in the direction perpendicular to the plasma propagation, where the magnetic field is directly coupled with only the electrons but not for the ions. Since the kinetic pressure of plasma is much larger than the magnetic pressure, the magnetic field is distorted and locally anti-parallel. We observe plasma collimations, cusp and plasmoid like features with optical diagnostics. The plasmoid propagates at the electron Alfvén velocity, indicating a reconnection driven by the electron dynamics

Errata - X-ray reflectivity of a Langmuir monolayer on water

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Two-dimensional order in the smectic F phase

The smectic F phase of TBPA is characterized by a stacking of weakly coupled pseudo-hexagonal layers. A careful analysis of the shape of the Debye-Scherrer lines enables a comparison to the theoretical predictions concerning the structure of 2d systems : a correlation length of about 250 A has been found within the layers under the assumption of completely uncoupled layers.La phase smectique F de TBPA est caractérisée par un empilement de couches pseudo-hexagonales faiblement couplées. L'analyse du profil des anneaux de poudre obtenus par diffraction de rayons X permet la confrontation aux résultats théoriques concernant la structure des systèmes 2d : on en déduit une longueur de corrélation dans la couche voisine de 250 A dans l'hypothèse où n'existe aucun couplage intercouches

Chihuahuan Desert Small Mammal Exclosure Study Ant Data

Animal consumers have important roles in ecosystems, determining plant species composition and structure, regulating rates of plant production and nutrients, and altering soil structure and chemistry. This is data for numbers and species of seed harvester ant nests mapped from each of the SMES study plots. Seed harvester ant nests were mapped on each of the study plots once each year in the autumn. Ant nest maps were drawn on to pre-designed plot diagrams. Each nest was located on the diagram in reference to one of the 36 vegetation quadrat marker posts. The distance from the post, direction from the post, and species name were plotted on the map diagram. Data such as total numbers of nests of each ant species, and spatial arrangement of nests, were then taken from the diagram maps. The following question was asked: Do small mammals interact with other herbivore and granivore consumers enough to affect the species composition and abundances of other consumers such as ants

Errata - X-ray reflectivity of a Langmuir monolayer on water

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X-ray method for the structural investigation of thin organic films

The structures of thin lamellar films can be determined through a combination of three X-ray experiments using synchrotron radiation. Diffraction experiments in the transmission geometry give the intralamellar ordering, the diffraction at small glancing angles yields the interlamellar organization, and the critical reflection provides the density measurement which is required to obtain the number of structural units per cell. This method is illustrated here with the study of an organic compound deposited in Langmuir-Blodgett films.Nous montrons que la simple conjugaison de trois techniques conventionnelles de rayons X permet une étude structurale des films minces lamellaires. La diffraction en transmission du rayonnement synchrotron fournit une détermination de l'arrangement intra-lamellaire, la diffraction en réflexion à petits angles, celle de l'ordre inter-lamellaire et enfin la réflexion critique donne une mesure de la densité nécessaire à l'obtention du nombre d'unités structurales par maille. Nous présentons une illustration de cette méthode à travers l'étude d'un composé organique déposé en couches de Langmuir-Blodgett