Explaining Violation Traces with Finite State Natural Language Generation Models

An essential element of any verification technique is that of identifying and communicating to the user, system behaviour which leads to a deviation from the expected behaviour. Such behaviours are typically made available as long traces of system actions which would benefit from a natural language explanation of the trace and especially in the context of business logic level specifications. In this paper we present a natural language generation model which can be used to explain such traces. A key idea is that the explanation language is a CNL that is, formally speaking, regular language susceptible transformations that can be expressed with finite state machinery. At the same time it admits various forms of abstraction and simplification which contribute to the naturalness of explanations that are communicated to the user

Coherent Pion Production by Neutrinos

I concentrate in this article on the reaction--coherent pion production by neutrinos incident on nuclei. A special effort is made in order to describe the approximations entering the calculation. I conclude that the reaction is well understood and with appropriate data for hadronic reactions is can be computed for low and high energies. Because of shortage of space I omitted the resonance analysis, which is described in articles with my collaborators.Comment: 4 pages. Proceedings of Conf. to be published by APS-Proceeding

A First-Principles Study of Zinc Oxide Honeycomb Structures

We present a first-principles study of the atomic, electronic, and magnetic properties of two-dimensional (2D), single and bilayer ZnO in honeycomb structure and its armchair and zigzag nanoribbons. In order to reveal the dimensionality effects, our study includes also bulk ZnO in wurtzite, zincblende, and hexagonal structures. The stability of 2D ZnO, its nanoribbons and flakes are analyzed by phonon frequency, as well as by finite temperature ab initio molecular-dynamics calculations. 2D ZnO in honeycomb structure and its armchair nanoribbons are nonmagnetic semiconductors but acquire net magnetic moment upon the creation of zinc-vacancy defect. Zigzag ZnO nanoribbons are ferromagnetic metals with spins localized at the oxygen atoms at the edges and have high spin polarization at the Fermi level. However, they change to nonmagnetic metal upon termination of their edges with hydrogen atoms. From the phonon calculations, the fourth acoustical mode specified as twisting mode is also revealed for armchair nanoribbon. Under tensile stress the nanoribbons are deformed elastically maintaining honeycomblike structure but yield at high strains. Beyond yielding point honeycomblike structure undergo a structural change and deform plastically by forming large polygons. The variation in the electronic and magnetic properties of these nanoribbons have been examined under strain. It appears that plastically deformed nanoribbons may offer a new class of materials with diverse properties.Comment: http://prb.aps.org/abstract/PRB/v80/i23/e23511

Modified Paschos-Wolfenstein relation and extraction of weak mixing angle sin^2 theta_W

The NuTeV collaboration reported anomalously large weak mixing angle sin^2 theta_W in comparison with the standard model prediction. Neutrino and antineutrino charged- and neutral-current events are analyzed for extracting sin^2 theta_W. Although the Paschos-Wolfenstein relation is not directly used in the analysis, it plays an important role in the determination. Noting that the target nucleus, iron, is not an isoscalar nucleus, we derive a leading-order expression for a modified Paschos-Wolfenstein relation for nuclei, which may have neutron excess. Then, using charge and baryon-number conservations for nuclei, we discuss a nuclear correction in the sin^2 theta_W determination. It is noteworthy that nuclear modifications are different between valence up- and down-quark distributions. We show this difference effect on the NuTeV sin^2 theta_W deviation.Comment: 5 pages, REVTeX4.0, revtex4.cls, url.sty, natbib.sty, revsymb.sty, 10pt.rtx, aps.rtx, amssymb.sty, amsfonts.sty, 3 eps figures. Phys. Rev. D in press. Email: [email protected] See also http://hs.phys.saga-u.ac.j

Pion Production in Neutrino-Nucleon Reactions

We construct a model for the weak pion production off the nucleon, which in addition to the weak excitation of the $\Delta(1232)$ resonance and its subsequent decay into $N\pi$, it includes also some background terms required by chiral symmetry. We re-fit the $C_5^A(q^2)$ form factor to the flux averaged $\nu_\mu p \to \mu^-p\pi^+$ ANL $q^2-$differential cross section data, finding a substantially smaller contribution of the $\Delta$ pole mechanism than traditionally assumed in the literature. We also show that the interference between the Delta pole and the background terms produces parity-violating contributions to the pion angular differential cross section.Comment: To appear in the proceedings of Fifth International Workshop on. Neutrino-Nucleus Interactions in the Few-GeV Region. May 30, 2007 - June 3, 2007. Fermilab, Batavia, Illinois US

Transaction costs and their implications to formation of contractual arrangements: aspects of machinery contracting by family farmers in the centro-serra region of Rio Grande do Sul.

A mecanização da produção agrícola desempenha um importante e crescente papel no curso do desenvolvimento agrícola e rural. A mecanização oferece diversas melhorias potenciais nos sistemas de produção tais como o incremento da produtividade da terra e do trabalho, a redução dos riscos, e aumento da qualidade e segurança alimentar de produtos de origem animal e vegetal. Entretanto, os investimentos necessários para compra de máquinas, especialmente para pequenos produtores, podem não ser a opção de menor custo em comparação com a obtenção de serviços de mecanização por meio de diferentes arranjos contratuais. Para .. escolher a melhor forma de contratar serviços de mecanização é necessário avaliar tanto os . custos convencionais das máquinas quanto os custos de transação, O principal objetivo desta pesquisa foi estimar a importância dos custos de transação na tomada de decisão sobre a seleção de arranjos contratuais alternativos para contratação de serviços de mecanização. Nossa hipótese era de. que os custos de transação podem ser maiores que os custos das máquinas, podendo, com isso, ser de cruclal Importância na seleção do tipo de arranjo contratual para contratar serviços de mecanização. Os dados empíricos de custos de máquinas e de transação foram coletados junto a agricultores familiares da Região Centro-Serra (RS), os quais contrataram serviços de colheita para milho de diferentes fornecedores formais e informais. Os resultados mostraram que os custos de transação podem ser mais elevados que os custos das máquinas e, com isso, influenciam de forma significativa a preferência agricultores familiares por determinado tipo de arranjo contratual para obtenção de serviços de mecanização. ABSTRACT - The mechanization of agricultural production plays an important and in course of time increasing role in the course of agricultural and rural development. Mechanization offers several potential improvements to farming systems such as increased land and labor productivity, reduction of risks, and increase of quality and food safety of animal and plant products. However, investments in own machinery, in particular for small holders, may not be the least-cost option in comparison with outsourcing the required machinery services through different contractual relationships. To choose the optimal contract for obtaining machinery services, it is necessary to evaluate conventional machinery costs as well as transaction costs. The main objective of this research was to assess the role of transaction costs in the choice among alternative contractual arrangements for provision of machinery services. Our hypothesis was that transaction costs can be higher than machinery costs, and therefore, they can play a leading role in the choice of contractual arrangements for provision of machinery services. The empirical data on conventional machinery and transaction costs were collected from farms in Southern Brazil that procure services for maize harvest through various informal and formal contractual forms. We found that transaction costs can be higher than conventional machinery costs, and therefore, influence the choice of contractual arrangement

Charge Symmetry Violation Corrections to Determination of the Weinberg Angle in Neutrino Reactions

We show that the correction to the Paschos-Wolfenstein relation associated with charge symmetry violation in the valence quark distributions is essentially model independent. It is proportional to a ratio of quark momenta that is independent of Q^2. This result provides a natural explanation of the surprisingly good agreement found between our earlier estimates within several different models. When applied to the recent NuTeV measurement, this effect significantly reduces the discrepancy with other determinations of the Weinberg angle.Comment: 7 pages, no figures; expanded discussion of N.ne.Z correction

Analysing the Security of Google's implementation of OpenID Connect

Many millions of users routinely use their Google accounts to log in to relying party (RP) websites supporting the Google OpenID Connect service. OpenID Connect, a newly standardised single-sign-on protocol, builds an identity layer on top of the OAuth 2.0 protocol, which has itself been widely adopted to support identity management services. It adds identity management functionality to the OAuth 2.0 system and allows an RP to obtain assurances regarding the authenticity of an end user. A number of authors have analysed the security of the OAuth 2.0 protocol, but whether OpenID Connect is secure in practice remains an open question. We report on a large-scale practical study of Google's implementation of OpenID Connect, involving forensic examination of 103 RP websites which support its use for sign-in. Our study reveals serious vulnerabilities of a number of types, all of which allow an attacker to log in to an RP website as a victim user. Further examination suggests that these vulnerabilities are caused by a combination of Google's design of its OpenID Connect service and RP developers making design decisions which sacrifice security for simplicity of implementation. We also give practical recommendations for both RPs and OPs to help improve the security of real world OpenID Connect systems