21,593 research outputs found

    Early Accurate Results for Advanced Analytics on MapReduce

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    Approximate results based on samples often provide the only way in which advanced analytical applications on very massive data sets can satisfy their time and resource constraints. Unfortunately, methods and tools for the computation of accurate early results are currently not supported in MapReduce-oriented systems although these are intended for `big data'. Therefore, we proposed and implemented a non-parametric extension of Hadoop which allows the incremental computation of early results for arbitrary work-flows, along with reliable on-line estimates of the degree of accuracy achieved so far in the computation. These estimates are based on a technique called bootstrapping that has been widely employed in statistics and can be applied to arbitrary functions and data distributions. In this paper, we describe our Early Accurate Result Library (EARL) for Hadoop that was designed to minimize the changes required to the MapReduce framework. Various tests of EARL of Hadoop are presented to characterize the frequent situations where EARL can provide major speed-ups over the current version of Hadoop.Comment: VLDB201

    Information Content in Data Sets for a Nucleated-Polymerization Model

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    We illustrate the use of tools (asymptotic theories of standard error quantification using appropriate statistical models, bootstrapping, model comparison techniques) in addition to sensitivity that may be employed to determine the information content in data sets. We do this in the context of recent models [23] for nucleated polymerization in proteins, about which very little is known regarding the underlying mechanisms; thus the methodology we develop here may be of great help to experimentalists

    Deep Residual Reinforcement Learning

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    We revisit residual algorithms in both model-free and model-based reinforcement learning settings. We propose the bidirectional target network technique to stabilize residual algorithms, yielding a residual version of DDPG that significantly outperforms vanilla DDPG in the DeepMind Control Suite benchmark. Moreover, we find the residual algorithm an effective approach to the distribution mismatch problem in model-based planning. Compared with the existing TD(kk) method, our residual-based method makes weaker assumptions about the model and yields a greater performance boost.Comment: AAMAS 202

    ESTIMATION OF IMPERFECT COMPETITION IN FOOD MARKETING: A DYNAMIC ANALYSIS OF THE GERMAN BANANA MARKET

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    Several studies have estimated the welfare effects of recent changes in the European Union's common policy on banana imports, based upon the assumption that the market is perfectly competitive. However, if the market is imperfectly competitive, predictions about changes in banana policy may be inaccurate. The objective of this paper is to estimate the degree of market imperfection in the German market for banana imports using dynamic methods. The hypothesis that this market is perfectly competitive is rejected, and, in addition, the degree of market imperfection is estimated to be higher using a dynamic model compared to previous static estimates.Marketing,
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