12,681 research outputs found

    Technology transfer between the government and the aerospace industry

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    The object of this working group panel was to review questions and issues pertaining to technology transfer between the government and the aerospace industry for use on both government and commercial space customer applications. The results of this review are presented in vugraph form

    Reforming IMF and World Bank governance : in search of simplicity, transparency and democratic legitimacy in the voting rules

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    We discuss the reform of the voting rules at the heart of the governance of the IMF and World Bank (the BWIs) in terms of three principles that we suggest ought to be fundamental: simplicity, transparency and democratic legitimacy. By simplicity we mean that the rules should make sense in terms of the purposes of the BWI and be easy to understand. By transparency we mean that the rules mean what they appear to mean in the sense of leading to the same distribution of voting power as the institution's designers intended. We show using voting power analysis that the inequality in the distribution of voting power among countries is greater than that of their voting weight. By democratic legitimacy, we consider whether we can reconcile weighted voting with democracy. Our conclusion is that the voting rules as they currently exist are far from satisfying any of these criteria and that recent reform proposals do not lead us to change this conclusion.

    Testing for spatial heterogeneity in functional MRI using the multivariate general linear model

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    Much current research in functional MRI employs multivariate machine learning approaches (e.g., support vector machines) to detect fine-scale spatial patterns from the temporal fluctuations of the neural signal. The aim of many studies is not classification, however, but investigation of multivariate spatial patterns, which pattern classifiers detect only indirectly. Here we propose a direct statistical measure for the existence of fine-scale spatial patterns (or spatial heterogeneity) applicable for fMRI datasets. We extend the univariate general linear model (typically used in fMRI analysis) to a multivariate case. We demonstrate that contrasting maximum likelihood estimations of different restrictions on this multivariate model can be used to estimate the extent of spatial heterogeneity in fMRI data. Under asymptotic assumptions inference can be made with reference to the X2 distribution. The test statistic is then assessed using simulated timecourses derived from real fMRI data. This demonstrates the utility of the proposed measure of heterogeneity as well as considerations in its application. Measuring spatial heterogeneity in fMRI has important theoretical implications in its own right and has potential uses for better characterising neurological conditions such as stroke and Alzheimer’s disease.wordsNeuroimaging ; Multivariate pattern analysis ; Maximum likelihood estimation ; Seemingly unrelated regression

    A new analysis of a priori voting power in the IMF : recent quota reforms give little cause for celebration

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    The weighted voting system used by the International Monetary Fund creates problems of democratic legitimacy since each member's influence or voting power is not in general equal to its voting weight. Using voting power analysis to analyse both the Board of Governors and the Executive Board, we show that it tends to enhance the power of the United States at the expense of all other members. We investigate the constituency system as a form of representative democracy, idealizing it as a compound voting body, and find that it gives disproportionately large power to some smaller European countries, particularly Belgium and Netherlands. We also find that many countries are effectively disenfranchised. Separate analyses are done for 2006 and 2012, before and after recent reforms, which have been billed as being radical, enhancing the voice of the poor and emerging markets, but the effects are disappointingly small

    Voting Power and Voting Blocs

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    We investigate the applicability of voting power indices, in particular the Penrose index (aka absolute Banzhaf index), in the analysis of voting blocs by means of a hypothetical voting body. We use the power of individual bloc members to study the implications of the formation of blocs and how voting power varies as bloc size varies. This technique of analysis has many real world applications to legislatures and international bodies. It can be generalised in many ways : the analysis is a priori (assuming formal voting and ignoring actual voting behaviour) but can be made empirical with voting data ; it examines the consequences of two blocs but can easily be extended to more.

    Voting Power Implications of a Unified European Representation at the IMF

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    We consider some of the implications of a proposed reform of the voting system of the IMF in which EU countries cease to be separately represented and are replaced by a single combined representative of the European bloc. The voting weight of the EU bloc is reduced accordingly. We analyse two cases: the Eurozone of 12 countries and the European Union of 25. Using voting power analysis we show that the reform could be very beneficial for the governance of the IMF, enhancing the voting power of individual member countries as a consequence of two large countervailing voting blocs. Specifically we analyse a range of EU voting weights and find the following for ordinary decisions requiring a simple majority: (1) All countries other than those of the EU and USA unambiguously gain power (measured absolutely or relatively); (2) The sum of powers of the EU bloc and USA is minimized when they have voting parity ; (3) The power of every other non-EU member is maximized when the EU and USA have parity ; (4) Each EU member could gain power - despite losing its seat and the reduction in EU voting weight - depending on the EU voting system that is adopted ; (5) The USA loses voting power (both absolutely and relatively) over ordinary decisions but retains its unilateral veto over special majority (85%) decisions (as does the EU bloc).IMF ; European Union ; Voting Power Indices ; Penrose Index ; Banzhaf Index

    System Identification for Nonlinear Control Using Neural Networks

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    An approach to incorporating artificial neural networks in nonlinear, adaptive control systems is described. The controller contains three principal elements: a nonlinear inverse dynamic control law whose coefficients depend on a comprehensive model of the plant, a neural network that models system dynamics, and a state estimator whose outputs drive the control law and train the neural network. Attention is focused on the system identification task, which combines an extended Kalman filter with generalized spline function approximation. Continual learning is possible during normal operation, without taking the system off line for specialized training. Nonlinear inverse dynamic control requires smooth derivatives as well as function estimates, imposing stringent goals on the approximating technique

    Minkowski decompositions for generalized associahedra of acyclic type

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    We give an explicit subword complex description of the generators of the type cone of the g-vector fan of a finite type cluster algebra with acyclic initial seed. This yields in particular a description of the Newton polytopes of the F-polynomials in terms of subword complexes as conjectured by S. Brodsky and the third author. We then show that the cluster complex is combinatorially isomorphic to the totally positive part of the tropicalization of the cluster variety as conjectured by D. Speyer and L. Williams.Comment: 17 pages. v2: updated and extended examples, added footnote that Theorem 1.4 also follows from [AHL20, Theorems 4.1 & 4.2
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