Browsing by Author "Xu, Fei"

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    On the smooth linear section of the Grassmannian Gr(2, n)
    (2012) Xu, Fei; Hassett, Brendan E.
    In this thesis, we will study the smooth linear section of the Grassmannian Gr(2, n). Explicitly, we give a criterion for the rationality of such linear section in terms of its codimension in the Plü ̈cker embedding in projective space. Moreover, to obtain a better understanding of the birational parametrization of these linear sections, we analyze their Hodge structures in the cases of even and odd codimensions. To be more precise, we provide numerous examples which suggest certain patterns of Hodge diamonds corresponding to even and odd cases and derive the proof of general patterns for codimension 3 smooth linear section of Gr(2, n) corresponding to odd and even n.
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    Risk analysis for data-intensive stochastic models
    (2012-12-25) Arumugam, Subramanian; Haas, Peter J.; Jampani, Ravindranath Chowdary; Jermaine, Christopher; Perez, Luis L.; Xu, Fei; International Business Machines Corporation; Rice University; University of Florida; United States Patent and Trademark Office
    A risk analysis system and method are provided. The system includes an analyzer for analyzing database instances by executing a query on each database instance and selecting a cutoff value. The analyzer also discards the sets of uncertainty data that yield query-result values below the cutoff value and retains the database instances that yield query-result values above the cutoff value as elite sets. The system also includes a cloner to replicate the elite sets, and a sampler to modify the elite sets so that each elite set is mutually statistically independent while still yielding query-result values above the cutoff value.