721 research outputs found

    Dependent types from counterexamples

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    Polymorphic Fractional Capabilities

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    Abstract. The capability calculus is a framework for statically reason-ing about program resources such as deallocatable memory regions. Frac-tional capabilities, originally proposed by Boyland for checking the deter-minism of parallel reads in multi-thread programs, extend the capability calculus by extending the capabilities to range over the rational numbers. Fractional capabilities have since found numerous applications, includ-ing race detection, buer bound inference, security analyses, and sep-aration logic. However, previous work on fractional capability systems either lacked polymorphism or lacked an ecient inference procedure. Automated inference is important for the application of the calculus to static analysis. This paper addresses the issue by presenting a polymor-phic fractional capability calculus that allows polynomial-time inference via a reduction to rational linear programming.

    Preserving Secrecy Under Refinement

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    We propose a general framework of secrecy and preservation of secrecy for labeled transition systems. Our definition of secrecy is parameterized by the distinguishing power of the observer, the properties to be kept secret, and the executions of interest, and captures a multitude of definitions in the literature. We define a notion of secrecy preserving refinement between systems by strengthening the classical trace-based refinement so that the implementation leaks a secret only when the specification also leaks it. We show that secrecy is in general not definable in µ-calculus, and thus not expressible in specification logics supported by standard model-checkers. However, we develop a simulation-based proof technique for establishing secrecy preserving refinement. This result shows how existing refinement checkers can be used to show correctness of an implementation with respect to a specification

    Sharper and Simpler Nonlinear Interpolants for Program Verification

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    Interpolation of jointly infeasible predicates plays important roles in various program verification techniques such as invariant synthesis and CEGAR. Intrigued by the recent result by Dai et al.\ that combines real algebraic geometry and SDP optimization in synthesis of polynomial interpolants, the current paper contributes its enhancement that yields sharper and simpler interpolants. The enhancement is made possible by: theoretical observations in real algebraic geometry; and our continued fraction-based algorithm that rounds off (potentially erroneous) numerical solutions of SDP solvers. Experiment results support our tool's effectiveness; we also demonstrate the benefit of sharp and simple interpolants in program verification examples

    Theory of Orbital Ordering, Fluctuation and Resonant X-ray Scattering in Manganites

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    A theory of resonant x-ray scattering in perovskite manganites is developed by applying the group theory to the correlation functions of the pseudospin operators for the orbital degree of freedom. It is shown that static and dynamical informations of the orbital state are directly obtained from the elastic, diffuse and inelastic scatterings due to the tensor character of the scattering factor. We propose that the interaction and its anisotropy between orbitals are directly identified by the intensity contour of the diffuse scattering in the momentum space.Comment: 4 pages, 1 figur

    A Multicenter, Randomized, Double-Blind, Placebo-Controlled Trial to Investigate the Effects of Kamishoyosan, a Traditional Japanese Medicine, on Menopausal Symptoms: The KOSMOS Study

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    Objective. The KOSMOS study, a multicenter, randomized, double-blind, placebo-controlled trial, investigated the effects and safety of kamishoyosan (TJ-24), a traditional Japanese medicine, in the treatment of climacteric disorder. Methods. Japanese women with climacteric disorder were administered a placebo during a 4-week run-in period, after which they were classified as placebo responders (R group) if their score on the modified Questionnaire for the Assessment of Climacteric Symptoms in Japanese Women (m-QACS) with excitability and irritability as the primary outcome improved by ≥ 3 points and as placebo nonresponders (NR group) otherwise. Members of the NR group were randomly allocated to receive either TJ-24 or placebo. After 12 weeks, their m-QACS scores, anxiety and depression, sleep, and overall quality of life (QOL) were compared. Results. The TJ-24 and placebo arms in the NR group included 20 patients each. The change in the m-QACS scores of members of the NR group for excitability and irritability at 12 weeks versus baseline was –3.1 ± 1.7 in the TJ-24 arm, a significant decrease, but compared with –2.7 ± 2.2 in the placebo arm, no significant difference was between two arms. However, the proportion of participants whose score improved by ≥3 points was significantly higher in the TJ-24 arm. In the subgroup analysis of premenopausal women, the changes in the score for excitability and irritability were significantly larger in the TJ-24 arm. The incidence of adverse drug reactions or adverse events did not differ between the two arms, and no serious events were reported. Conclusion. Although no significant difference was identified for the primary outcome, a significantly higher proportion of patients who received TJ-24 displayed improvement. Its high level of safety and effects on excitability and irritability in premenopausal women suggest that TJ-24 may be a useful treatment
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