6,504 research outputs found

    Managing uncertainty of XML schema matching

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    Despite of advances in machine learning technologies, a schema matching result between two database schemas (e.g., those derived from COMA++) is likely to be imprecise. In particular, numerous instances of "possible mappings" between the schemas may be derived from the matching result. In this paper, we study the problem of managing possible mappings between two heterogeneous XML schemas. We observe that for XML schemas, their possible mappings have a high degree of overlap. We hence propose a novel data structure, called the block tree, to capture the commonalities among possible mappings. The block tree is useful for representing the possible mappings in a compact manner, and can be generated efficiently. Moreover, it supports the evaluation of probabilistic twig query (PTQ), which returns the probability of portions of an XML document that match the query pattern. For users who are interested only in answers with k-highest probabilities, we also propose the top-k PTQ, and present an efficient solution for it. The second challenge we have tackled is to efficiently generate possible mappings for a given schema matching. While this problem can be solved by existing algorithms, we show how to improve the performance of the solution by using a divide-andconquer approach. An extensive evaluation on realistic datasets show that our approaches significantly improve the efficiency of generating, storing, and querying possible mappings. © 2010 IEEE.published_or_final_versionThe IEEE 26th International Conference on Data Engineering (ICDE 2010), Long Beach, CA., 1-6 March 2010. In International Conference on Data Engineering. Proceedings, 2010, p. 297-30

    Applying Web 2.0 in medical-related organizations

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    This study investigated the application of Web 2.0 to medical-related organizations. Thirty organizations participated in an online survey asking their perceived purposes, benefits and difficulties in using Web 2.0. The selected organizations fell into three categories: university medical libraries, hospitals, and non-profit organizations. Fourteen (46.7%) organizations were currently using Web 2.0, ten (33.3%) planned to use it in the future and six (20%) would not consider using it. A phone interview was further conducted with eight organizations (26.7%) about their opinion on Web 2.0. Results showed that most participants found the application of Web 2.0 beneficial to their organizations. Implications of this study for helping medical-related organizations make decisions regarding the use of Web 2.0 technologies in their organizations are discussed.postprintThe 6th International Conference on Knowledge Management (ICKM 2009), Hong Kong, 3-4 December 2009. In Proceedings of ICKM, 2009, p. 1-1

    High-energy scale revival and giant kink in the dispersion of a cuprate superconductor

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    In the present photoemission study of a cuprate superconductor Bi1.74Pb0.38Sr1.88CuO6+delta, we discovered a large scale dispersion of the lowest band, which unexpectedly follows the band structure calculation very well. The incoherent nature of the spectra suggests that the hopping-dominated dispersion occurs possibly with the assistance of local spin correlations. A giant kink in the dispersion is observed, and the complete self-energy containing all interaction information is extracted for a doped cuprate in the low energy region. These results recovered significant missing pieces in our current understanding of the electronic structure of cuprates.Comment: 4 pages, 3 figures, submitted to Phys. Rev. Lett. on May 21, 200

    Brownian bridges to submanifolds

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    We introduce and study Brownian bridges to submanifolds. Our method involves proving a general formula for the integral over a submanifold of the minimal heat kernel on a complete Riemannian manifold. We use the formula to derive lower bounds, an asymptotic relation and derivative estimates. We also see a connection to hypersurface local time. This work is motivated by the desire to extend the analysis of path and loop spaces to measures on paths which terminate on a submanifold

    Chemical speciation of nanoparticles surrounding metal-on-metal hips.

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    Spectromicroscopy of tissue surrounding failed CoCr metal-on-metal hip replacements detected corroded nanoscale debris in periprosthetic tissue in two chemical states, with concomitant mitochondrial damage. The majority of debris contained Cr(3+), with trace amounts of oxidised cobalt. A minority phase containing a core of metallic chromium and cobalt was also observed

    Depression und Suizidalität

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    Even if the freedom to suicide is part of our human existence, about 90% of all suicides occur in the context of psychiatric disorders and thus in states of limited power of judgment. Depressive disorders represent the most frequent cause for suicides. Thus, optimization of medical care for depressive patients is one of the most promising strategies to prevent suicides. In the context of the `Nuremberg Alliance Against Depression' it came to an obvious reduction of suicidal acts compared to a baseline year and compared to the control region of Wurzburg. The reduction could be reached by a cooperation with GPs, multipliers such as teachers, priests, geriatric caregivers and the media, through intensive public relations work and through support of self help activities. This approach is carried forward within the Germany-wide `Alliance Against Depression' and within the `European Alliance Against Depression' ( EAAD) which is funded by the European Commission. In the last part of the article the suicide- preventive, but also the possible suicide-inducing effect of antidepressants is discussed

    Characterization of insulating coatings for wind-and-react coil fabrication

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    Electrical insulation breakdown between conductor and coil parts and structures is a limiting factor in the performance of high-field magnets. We have evaluated various insulation coatings for possible application in both Nb Sn and Bi-2212 coil fabrication. Such coatings must be robust to maintain structural integrity and provide adequate voltage standoff after the wind-and-react coil fabrication process. Such processes are characterized by reaction temperatures of 650°C in an inert atmosphere for Nb Sn and 890°C in a pure oxygen atmosphere for Bi-2212, and down to cryogenic temperatures when coils are in service. We present a method of testing standardized samples and report the performance characteristics of oxide layers produced (or applied) by plasma-spray, surface conversion, and "paintable" coatings in common areas of voltage breakdown in coil parts. We also address material compatibility and durability during high-temperature heat treatment and cryogenic shock. Suitable coatings selected in the testing process will be instrumental in improving the performance of future wind-and-react coils. © 2014 AIP Publishing LLC. 3

    Model-based probabilistic frequent itemset mining

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    Data uncertainty is inherent in emerging applications such as location-based services, sensor monitoring systems, and data integration. To handle a large amount of imprecise information, uncertain databases have been recently developed. In this paper, we study how to efficiently discover frequent itemsets from large uncertain databases, interpreted under the Possible World Semantics. This is technically challenging, since an uncertain database induces an exponential number of possible worlds. To tackle this problem, we propose a novel methods to capture the itemset mining process as a probability distribution function taking two models into account: the Poisson distribution and the normal distribution. These model-based approaches extract frequent itemsets with a high degree of accuracy and support large databases. We apply our techniques to improve the performance of the algorithms for (1) finding itemsets whose frequentness probabilities are larger than some threshold and (2) mining itemsets with the {Mathematical expression} highest frequentness probabilities. Our approaches support both tuple and attribute uncertainty models, which are commonly used to represent uncertain databases. Extensive evaluation on real and synthetic datasets shows that our methods are highly accurate and four orders of magnitudes faster than previous approaches. In further theoretical and experimental studies, we give an intuition which model-based approach fits best to different types of data sets. © 2012 The Author(s).published_or_final_versio

    Paradoxical roles of antioxidant enzymes:Basic mechanisms and health implications

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    Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are generated from aerobic metabolism, as a result of accidental electron leakage as well as regulated enzymatic processes. Because ROS/RNS can induce oxidative injury and act in redox signaling, enzymes metabolizing them will inherently promote either health or disease, depending on the physiological context. It is thus misleading to consider conventionally called antioxidant enzymes to be largely, if not exclusively, health protective. Because such a notion is nonetheless common, we herein attempt to rationalize why this simplistic view should be avoided. First we give an updated summary of physiological phenotypes triggered in mouse models of overexpression or knockout of major antioxidant enzymes. Subsequently, we focus on a series of striking cases that demonstrate “paradoxical” outcomes, i.e., increased fitness upon deletion of antioxidant enzymes or disease triggered by their overexpression. We elaborate mechanisms by which these phenotypes are mediated via chemical, biological, and metabolic interactions of the antioxidant enzymes with their substrates, downstream events, and cellular context. Furthermore, we propose that novel treatments of antioxidant enzyme-related human diseases may be enabled by deliberate targeting of dual roles of the pertaining enzymes. We also discuss the potential of “antioxidant” nutrients and phytochemicals, via regulating the expression or function of antioxidant enzymes, in preventing, treating, or aggravating chronic diseases. We conclude that “paradoxical” roles of antioxidant enzymes in physiology, health, and disease derive from sophisticated molecular mechanisms of redox biology and metabolic homeostasis. Simply viewing antioxidant enzymes as always being beneficial is not only conceptually misleading but also clinically hazardous if such notions underpin medical treatment protocols based on modulation of redox pathways
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