1,122 research outputs found

    The simple analytics of commodity futures markets: do they stabilize prices? Do they raise welfare?

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    This paper uses a simple, graphical approach to analyze what happens to commodity prices and economic welfare when futures markets are introduced into an economy. It concludes that these markets do not necessarily make prices more or less stable. It also concludes that, contrary to common belief, whatever happens to commodity prices is not necessarily related to what happens to the economic welfare of market participants: even when futures markets reduce the volatility of prices, some people can be made worse off. These conclusions come from a series of models that differ in their assumptions about the primary function of futures markets, the structure of the industries involved, and the tastes and technologies of the market participants.Futures ; Commercial products

    Jordan-Schwinger realizations of three-dimensional polynomial algebras

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    A three-dimensional polynomial algebra of order mm is defined by the commutation relations [P0,P±][P_0, P_\pm] == ±P±\pm P_\pm, [P+,P−][P_+, P_-] == ϕ(m)(P0)\phi^{(m)}(P_0) where ϕ(m)(P0)\phi^{(m)}(P_0) is an mm-th order polynomial in P0P_0 with the coefficients being constants or central elements of the algebra. It is shown that two given mutually commuting polynomial algebras of orders ll and mm can be combined to give two distinct (l+m+1)(l+m+1)-th order polynomial algebras. This procedure follows from a generalization of the well known Jordan-Schwinger method of construction of su(2)su(2) and su(1,1)su(1,1) algebras from two mutually commuting boson algebras.Comment: 10 pages, LaTeX2

    A Multi-Step Nonlinear Dimension-Reduction Approach with Applications to Bigdata

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    In this paper, a multi-step dimension-reduction approach is proposed for addressing nonlinear relationships within attributes. In this work, the attributes in the data are first organized into groups. In each group, the dimensions are reduced via a parametric mapping that takes into account nonlinear relationships. Mapping parameters are estimated using a low rank singular value decomposition (SVD) of distance covariance. Subsequently, the attributes are reorganized into groups based on the magnitude of their respective singular values. The group-wise organization and the subsequent reduction process is performed for multiple steps until a singular value-based user-defined criterion is satisfied. Simulation analysis is utilized to investigate the performance with five big data-sets

    Direct Error Driven Learning for Deep Neural Networks with Applications to Bigdata

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    In this paper, generalization error for traditional learning regimes-based classification is demonstrated to increase in the presence of bigdata challenges such as noise and heterogeneity. To reduce this error while mitigating vanishing gradients, a deep neural network (NN)-based framework with a direct error-driven learning scheme is proposed. To reduce the impact of heterogeneity, an overall cost comprised of the learning error and approximate generalization error is defined where two NNs are utilized to estimate the costs respectively. To mitigate the issue of vanishing gradients, a direct error-driven learning regime is proposed where the error is directly utilized for learning. It is demonstrated that the proposed approach improves accuracy by 7 % over traditional learning regimes. The proposed approach mitigated the vanishing gradient problem and improved generalization by 6%
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