A Discrete Logarithm-based Approach to Compute Low-Weight Multiples of Binary Polynomials

Being able to compute efficiently a low-weight multiple of a given binary polynomial is often a key ingredient of correlation attacks to LFSR-based stream ciphers. The best known general purpose algorithm is based on the generalized birthday problem. We describe an alternative approach which is based on discrete logarithms and has much lower memory complexity requirements with a comparable time complexity.Comment: 12 page

Possible, alternative explanations of the T2K observation of the nu_e appearance from an initial nu_mu

An alternative explanation to the emergence of sin^2(2 theta_13) > 0 is discussed. It is pointed out that the recorded T2K events might have been due to some other new physics in the neutrino sector, related to the LSND/MiniBooNE sterile neutrino anomalies, for which there is nowadays a growing evidence. The presently running ICARUS detector with the CNGS beam will be able to distinguish between these two possible sources of the effectComment: 5 pages, 1 figur

The interaction-strength interpolation method for main-group chemistry: benchmarking, limitations, and perspectives

We have tested the original interaction-strength-interpolation (ISI) exchange-correlation functional for main group chemistry. The ISI functional is based on an interpolation between the weak and strong coupling limits and includes exact-exchange as well as the G\"orling-Levy second-order energy. We have analyzed in detail the basis-set dependence of the ISI functional, its dependence on the ground-state orbitals, and the influence of the size-consistency problem. We show and explain some of the expected limitations of the ISI functional (i.e. for atomization energies), but also unexpected results, such as the good performance for the interaction energy of dispersion-bonded complexes when the ISI correlation is used as a correction to Hartree-Fock.Comment: 20 pages, 20 figure

Atmospheric neutrinos in a Large Liquid Argon detector

In view of the evaluation of the physics goals of a large Liquid Argon TPC, evolving from the ICARUS technology, we have studied the possibility of performing precision measurements on atmospheric neutrinos. For this purpose we have improved existing Monte Carlo neutrino event generators based on FLUKA and NUX by including the 3-flavor oscillation formalism and the numerical treatment of Earth matter effects. By means of these tools we have studied the sensitivity in the measurement of Theta(23) through the accurate measurement of electron neutrinos. The updated values for Delta m^2(23) from Super-Kamiokande and the mixing parameters as obtained by solar and KamLand experiments have been used as reference input, while different values of Theta(13) have been considered. An exposure larger than 500 kton yr seems necessary in order to achieve a significant result, provided that the present knowledge of systematic uncertainties is largely improved.Comment: Talk given at the worksgop "Cryogenic Liquid Detectors for Future Particle Physics", LNGS (Italy) March 13th-14th, 200

Validation of Survey Data on Income and Employment: The ISMIE Experience

This report derives from the project "Improving survey measurement of income and employment (ISMIE)" which investigates measurement error in survey data on income and employment, using a UK sub-sample of the European Household Community Panel (ECHP). In this paper we describe the process of collecting validation data and the outcomes of the process. Validation data were obtained from two sources: employers' records and government benefit data from the Department for Work and Pensions (DWP). The former provided information on occupation and employment status, gross and net pay, membership of company pension schemes and industry sector. The latter provided histories of benefit receipt and tax credits, for example, child, disability, housing and unemployment benefits, pensions and income support. In the survey interview, respondents were asked for written permission both to obtain their DWP records and to contact their employer. They were also asked to provide information that would facilitate the process of obtaining the validation data: National Insurance number (NINO) and employer contact details. Subsequently, DWP records were extracted using a non-hierarchical matching strategy, based on different combinations of identifying variables obtained in the survey (NINO, sex, date of birth, name and postcode), and a survey of employers was carried out (mail, with telephone follow-up). The representativeness of the validation samples obtained depends on the co-operation of both survey respondents and providers of validation data, as well as errors in the matching process. We report permission rates, proportions providing matching items, match rates for the DWP data and response rates to the employer survey. We identify correlates of these measures of success at each stage of the validation process in terms of substantive characteristics of the survey respondents. Variation by subgroups is identified and implications for the representativeness of the validation sample are discussed.

Semiclassical atom theory applied to solid-state physics

Using the semiclassical neutral atom theory, we extend to fourth order the modified gradient expansion of the exchange energy of density functional theory. This expansion can be applied both to large atoms and solid-state problems. Moreover, we show that it can be employed to construct a simple and non-empirical generalized gradient approximation (GGA) exchange-correlation functional competitive with state-of-the-art GGAs for solids, but also reasonably accurate for large atoms and ordinary chemistry.Comment: 10 pages, 7 figure

The Effects of Dependent Interviewing on Responses to Questions on Income Sources

Using an experimental design, we compare two alternative approaches to dependent interviewing (proactive and reactive) with traditional independent interviewing on a module of questions about sources of income. We believe this to be the first large-scale quantitative comparison of proactive and reactive dependent interviewing. The three approaches to questioning are compared in terms of their impact on under-reporting of income sources and related bivariate statistics. The study design also enables identification of the characteristics of respondents whose responses are sensitive to the mode of interviewing. We conclude that under-reporting can be significantly greater with independent interviewing than with either form of dependent interviewing, especially for income sources that are relatively common or relatively easy to forget. We find that dependent interviewing is particularly helpful as a recall aid for respondents below retirement age and registered disabled persons.

Assessment of the TCA functional in computational chemistry and solid-state physics

We assess the Tognetti-Cortona-Adamo (TCA) generalized gradient approximation correlation functional [J. Chem. Phys. 128:034101 (2008)] for a variety of electronic systems. We find that, even if the TCA functional is not exact for the uniform electron gas, it is very accurate for the jellium surface correlation energies and it gives a realistic description of the quantum oscillations and surface effects of various jellium clusters, that are important model systems in computational chemistry and solid-state physics. When the TCA correlation is combined with the non-empirical PBEint, Wu-Cohen, and PBEsol$_b$ exchange functionals, the resulting exchange-correlation approximations provide good performances for a broad palette of systems and properties, being reasonably accurate for thermochemistry and geometry of molecules, transition metal complexes, non-covalent interactions,equilibrium lattice constants, bulk moduli, and cohesive energies of solids.Comment: 14 pages, 6 figure