436 research outputs found

    Continuous Functions on Final Comodels of Free Algebraic Theories

    Full text link
    In 2009, Ghani, Hancock and Pattinson gave a tree-like representation of stream processors ANBNA^{\mathbb{N}} \rightarrow B^{\mathbb{N}}. In 2021, Garner showed that this representation can be established in terms of algebraic theory and comodels: the set of infinite streams ANA^{\mathbb{N}} is the final comodel of the algebraic theory of AA-valued input TA\mathbb{T}_A and the set of stream processors Top(AN,BN)\mathit{Top}(A^{\mathbb{N}},B^{\mathbb{N}}) can be seen as the final TA\mathbb{T}_A-TB\mathbb{T}_B-bimodel. In this paper, we generalize Garner's results to the case of free algebraic theories.Comment: 17 page

    Continuous Functions on Final Comodels of Free Algebraic Theories

    Get PDF
    In 2009, Ghani, Hancock and Pattinson gave a tree-like representation of stream processors A[N] → B[N]. In 2021, Garner showed that this representation can be established in terms of algebraic theory and comodels: the set of infinite streams A[N] is the final comodel of the algebraic theory of A-valued input [T][A] and the set of stream processors Top(A[N] , B[N]) can be seen as the final [T][A]-[T][B]-bimodel. In this paper, we generalize Garner's results to the case of free algebraic theories

    Log-rank test with coarsened exact matching

    Full text link
    It is of special importance in the clinical trial to compare survival times between the treatment group and the control group. Propensity score methods with a logistic regression model are often used to reduce the effects of confounders. However, the modeling of complex structures between the covariates, the treatment assignment and the survival time is difficult. In this paper, we consider coarsened exact matching (CEM), which does not need any parametric models, and we propose the weighted log-rank statistic based on CEM. We derive asymptotic properties of the weighted log-rank statistic, such as the weak convergence to a Gaussian process in Skorokhod space, in particular the asymptotic normality, under the null hypothesis and the consistency of the log-rank test. Simulation studies show that the log-rank statistic based on CEM is more robust than the log-rank statistic based on the propensity score

    Factor Analysis of Damage to Small Earth Dams Due to the 1995 Hyogoken-Nambu Earthquake

    Get PDF
    Damage to small earth dams due to the Hyogoken-Namby Earthquake of January 17, 1995 is discussed. Investigations of 266 dams were conducted in the area where the JMA seismic intensity was 5 or higher, and which were located within about 50 kilometers from the earthquake source fault. Small earth dams suffered various forms of damage such as longitudinal cracking, transverse cracking, settlement and deformation of the dam body. The damage to small earth dams was classified into five grades from no damage to severe damage such as a complete failure. The damage grade was analyzed by several factors such as distance from the fault, topography and geology, intensity of quake motion, direction of dam axis against the fault, year of completion, and height of dam. The characteristics of factors affecting damage to small earth dams were evaluated

    Simultaneous Improvements in Performance and Durability of an Octahedral PtNix/C Electrocatalyst for Next-Generation Fuel Cells by Continuous, Compressive, and Concave Pt Skin Layers

    Get PDF
    Simultaneous improvements in oxygen reduction reaction (ORR) activity and long-term durability of Pt-based cathode catalysts are indispensable for the development of next-generation polymer electrolyte fuel cells but are still a major dilemma. We present a robust octahedral core–shell PtNix/C electrocatalyst with high ORR performance (mass activity and surface specific activity 6.8–16.9 and 20.3–24.0 times larger than those of Pt/C, respectively) and durability (negligible loss after 10000 accelerated durability test (ADT) cycles). The key factors of the robust octahedral nanostructure (core–shell Pt73Ni27/C) responsible for the remarkable activity and durability were found to be three continuous Pt skin layers with 2.0–3.6% compressive strain, concave facet arrangements (concave defects and high coordination), a symmetric Pt/Ni distribution, and a Pt67Ni33 intermetallic core, as found by STEM-EDS, in situ XAFS, XPS, etc. The robust core–shell Pt73Ni27/C was produced by the partial release of the stress, Pt/Ni rearrangement, and dimension reduction of an as-synthesized octahedral Pt50Ni50/C with 3.6–6.7% compressive Pt skin layers by Ni leaching during the activation process. The present results on the tailored synthesis of the PtNix structure and composition and the better control of the robust catalytic architecture renew the current knowledge and viewpoint for instability of octahedral PtNix/C samples to provide a new insight into the development of next-generation PEFC cathode catalysts
    corecore