Asymptotic Results for an Extreme Value Estimator of the Autocorrelation Coefficient for a First Order Autoregressive Sequence

Author(s):  
W. P. McCormick ◽  
G. Mathew
2007 ◽  
Vol DMTCS Proceedings vol. AH,... (Proceedings) ◽  
Author(s):  
Svante Janson

International audience We study the space requirements of a sorting algorithm where only items that at the end will be adjacent are kept together. This is equivalent to the following combinatorial problem: Consider a string of fixed length n that starts as a string of 0's, and then evolves by changing each 0 to 1, with the n changes done in random order. What is the maximal number of runs of 1's? We give asymptotic results for the distribution and mean. It turns out that, as in many problems involving a maximum, the maximum is asymptotically normal, with fluctuations of order $n^{1/2}$, and to the first order well approximated by the number of runs at the instance when the expectation is maximized, in this case when half the elements have changed to 1; there is also a second order term of order $n^{1/3}$. We also treat some variations, including priority queues and sock-sorting.


Econometrica ◽  
2020 ◽  
Vol 88 (4) ◽  
pp. 1515-1551
Author(s):  
Tim Bollerslev ◽  
Jia Li ◽  
Andrew J. Patton ◽  
Rogier Quaedvlieg

We propose a decomposition of the realized covariance matrix into components based on the signs of the underlying high‐frequency returns, and we derive the asymptotic properties of the resulting realized semicovariance measures as the sampling interval goes to zero. The first‐order asymptotic results highlight how the same‐sign and mixed‐sign components load differently on economic information related to stochastic correlation and jumps. The second‐order asymptotic results reveal the structure underlying the same‐sign semicovariances, as manifested in the form of co‐drifting and dynamic “leverage” effects. In line with this anatomy, we use data on a large cross‐section of individual stocks to empirically document distinct dynamic dependencies in the different realized semicovariance components. We show that the accuracy of portfolio return variance forecasts may be significantly improved by exploiting the information in realized semicovariances.


1970 ◽  
Vol 7 (01) ◽  
pp. 99-113 ◽  
Author(s):  
C. W. Anderson

Let ξn be the maximum of a set of n independent random variables with common distribution function F whose support consists of all sufficiently large positive integers. Some of the classical asymptotic results of extreme value theory fail to apply to ξn for such F and this paper attempts to find weaker ones which give some description of the behaviour of ξn as n → ∞. These are then applied to the extreme value theory of certain regenerative stochastic processes.


1986 ◽  
Vol 23 (4) ◽  
pp. 379-386 ◽  
Author(s):  
Vinay Kanetkar ◽  
Charles B. Weinberg ◽  
Doyle L. Weiss

The authors briefly review the literature associated with the autocorrelated current effects model and present a simple procedure that recovers its parameters from time-aggregated data when the level of aggregation is known. The procedure is based partly on the estimation of a first-order autocorrelation coefficient. The procedure is illustrated and its properties are compared with those of a GLS procedure by means of a Monte Carlo experiment. In many of the tested cases, there is good recovery of the microparameters with aggregated data.


1978 ◽  
Vol 89 (2) ◽  
pp. 209-222 ◽  
Author(s):  
Edward E. O'Brien

A model probability density equation is obtained by approximating the convective and diffusive terms in a single-point density formulation of homogeneous turbulent scalar transport, with first-order reaction, in a plume. The equation, which includes the intermittency factor of the scalar field explicitly, is then shown to support similarity solutions under some constraining assumptions. Comparison of the similarity solutions with field measurements of conditioned concentrations shows that they can reproduce the general features of the data for both low intermittency and high intermittency measurement regimes. On the basis of these asymptotic results a speculative modelling of the terms representing entrainment at the plume interface is proposed and a class of similarity solutions for the intermittency factor is obtained by numerical integration.


2019 ◽  
Vol 44 (3) ◽  
pp. 235-246
Author(s):  
Paul M. Mwasame ◽  
Norman J. Wagner ◽  
Antony N. Beris

Abstract The mechanics of understanding a new application of the bracket theory of Non-Equilibrium Thermodynamics that allows for the incorporation of microstructural inertia effects within conformation tensor-based constitutive models of macroscopic material behavior is presented. Introducing inertia effects generally requires the replacement of a first order in time evolution equation for the conformation tensor by a second order one. Through the analysis of a simple damped oscillator we bring forward here the close connection to the structural dissipation brackets present in the two cases, with the weights being inverted as one transitions from the inertialess to the inertial description. Moreover, one may also describe inertial effects in material flow in certain situations through a simple modification of the first order evolution equation for the conformation tensor, which consists of adding a new non-affine term that couples the conformation and the vorticity tensors, as detailed in a recent publication (P. M. Mwasame, N. J. Wagner and A. N. Beris, Phys. Fluids, 30 (2018), 030704). As shown there, when applied to the low particle Reynolds flow of dilute emulsions, this reduced inertial flow model provides predictions consistent with literature-available microscopically based asymptotic results.


1970 ◽  
Vol 7 (1) ◽  
pp. 99-113 ◽  
Author(s):  
C. W. Anderson

Let ξn be the maximum of a set of n independent random variables with common distribution function F whose support consists of all sufficiently large positive integers. Some of the classical asymptotic results of extreme value theory fail to apply to ξn for such F and this paper attempts to find weaker ones which give some description of the behaviour of ξn as n → ∞. These are then applied to the extreme value theory of certain regenerative stochastic processes.


Extremes ◽  
2020 ◽  
Vol 23 (4) ◽  
pp. 501-520
Author(s):  
Edoardo Vignotto ◽  
Sebastian Engelke

Abstract Classification tasks usually assume that all possible classes are present during the training phase. This is restrictive if the algorithm is used over a long time and possibly encounters samples from unknown new classes. It is therefore fundamental to develop algorithms able to distinguish between normal and abnormal test data. In the last few years, extreme value theory has become an important tool in multivariate statistics and machine learning. The recently introduced extreme value machine, a classifier motivated by extreme value theory, addresses this problem and achieves competitive performance in specific cases. We show that this algorithm has some theoretical and practical drawbacks and can fail even if the recognition task is fairly simple. To overcome these limitations, we propose two new algorithms for anomaly detection relying on approximations from extreme value theory that are more robust in such cases. We exploit the intuition that test points that are extremely far from the training classes are more likely to be abnormal objects. We derive asymptotic results motivated by univariate extreme value theory that make this intuition precise. We show the effectiveness of our classifiers in simulations and on real data sets.


2019 ◽  
Vol 42 ◽  
Author(s):  
Daniel J. Povinelli ◽  
Gabrielle C. Glorioso ◽  
Shannon L. Kuznar ◽  
Mateja Pavlic

Abstract Hoerl and McCormack demonstrate that although animals possess a sophisticated temporal updating system, there is no evidence that they also possess a temporal reasoning system. This important case study is directly related to the broader claim that although animals are manifestly capable of first-order (perceptually-based) relational reasoning, they lack the capacity for higher-order, role-based relational reasoning. We argue this distinction applies to all domains of cognition.


1984 ◽  
Vol 75 ◽  
pp. 461-469 ◽  
Author(s):  
Robert W. Hart

ABSTRACTThis paper models maximum entropy configurations of idealized gravitational ring systems. Such configurations are of interest because systems generally evolve toward an ultimate state of maximum randomness. For simplicity, attention is confined to ultimate states for which interparticle interactions are no longer of first order importance. The planets, in their orbits about the sun, are one example of such a ring system. The extent to which the present approximation yields insight into ring systems such as Saturn's is explored briefly.


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