16,590 research outputs found

    Multiple Hypothesis Testing in Pattern Discovery

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    The problem of multiple hypothesis testing arises when there are more than one hypothesis to be tested simultaneously for statistical significance. This is a very common situation in many data mining applications. For instance, assessing simultaneously the significance of all frequent itemsets of a single dataset entails a host of hypothesis, one for each itemset. A multiple hypothesis testing method is needed to control the number of false positives (Type I error). Our contribution in this paper is to extend the multiple hypothesis framework to be used with a generic data mining algorithm. We provide a method that provably controls the family-wise error rate (FWER, the probability of at least one false positive) in the strong sense. We evaluate the performance of our solution on both real and generated data. The results show that our method controls the FWER while maintaining the power of the test.Comment: 28 page

    Some Experimental Signatures to look for Time-reversal Violating superconductors

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    We discuss some experimental signatures associated with the topological structures of unconventional superconductor order parameters of form dx2y2+ixd_{x^2-y^2}+ix, where x=s,px±pyx=s,p_x \pm p_y, or dxyd_{xy}. Specifically, we study the topological surface states on the (110)(110) and equivalent surfaces of such superconductors which are observable in Andreev tunneling experiments, as well as evaluate the magnetic flux trapped in superconducting rings of such superconductors with multiple grain-boundary Josephson junctions. Previous experiments are examined and several new experiments suggested.Comment: 11 pages, 3 figure

    Spinon-Holon binding in tJt-J model

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    Using a phenomenological model, we discuss the consequences of spinon-holon binding in the U(1) slave-boson approach to tJt-J model. Within a small xx (x=x= hole concentration) expansion, we show that spinon-holon binding produces a pseudo-gap normal state with a segmented Fermi surface and the superconducting state is formed by opening an "additional" d-wave gap on the segmented Fermi surface. The d-wave gap merge with the pseudo-gap smoothly as temperature T0T\to0. The quasi-particles in the superconducting state are coupled to external electromagnetic field with a coupling constant of order xγx^{\gamma} where 0γ1/20\leq\gamma\leq1/2, depending on the strength of the effective spinon-holon binding potential.Comment: 9 pages, 3 figure

    Transitions to Measure Synchronization in Coupled Hamiltonian Systems

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    Transitions to measure synchronization in two coupled ϕ4\phi ^{4} lattices are investigated based on numerical simulations. The relationship between measure synchronization (MS), phase locking and system's total energy is studied both for periodic and chaotic states. Two different scalings are discovered during the process to MS according to phase locking. Random walk like phase synchronization in chaotic measure synchronization is found, and phase locking interrupted by phase slips irregularly is also investigated. Meanwhile, related analysis is qualitative given to explain this phenomenon.Comment: 10 pages, 6 figure
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