scholarly journals Testing for correlation between traits under directional evolution

2019 ◽  
Author(s):  
Manuela Royer-Carenzi ◽  
Gilles Didier
Keyword(s):  
Quantitative Traits ◽  
Probability Distributions ◽  
Generalized Least Squares ◽  
The Other ◽  
Independent Contrasts ◽  
Cranial Capacity ◽  
Directional Evolution ◽  
Regression Approach ◽  
Correlation Tests ◽  
Linear Trends

AbstractBeing confounding factors, directional trends are likely to make two quantitative traits appear as spuriously correlated. By determining the probability distributions of independent contrasts when traits evolve following Brownian motions with linear trends, we show that the standard independent contrasts can not be used to test for correlation in this situation. We propose a multiple regression approach which corrects the bias caused by directional evolution.We show that our approach is equivalent to performing a Phylogenetic Generalized Least Squares (PGLS) analysis with tip times as covariables by providing a new and more general proof of the equivalence between PGLS and independent contrasts methods.Our approach is assessed and compared with three previous correlation tests on data simulated in various situations and overall outperforms all the other methods. The approach is next illustrated on a real dataset to test for correlation between hominin cranial capacity and body mass.

Seismic hazard sensitivity analysis: A multi-parameter approach

1991 ◽  
Vol 81 (3) ◽  
pp. 796-817
Author(s):  
Nitzan Rabinowitz ◽  
David M. Steinberg
Keyword(s):  
Sensitivity Analysis ◽  
Seismic Hazard ◽  
Subjective Probability ◽  
Probability Distributions ◽  
Input Parameter ◽  
The Other ◽  
Probabilistic Assessment ◽  
Input Parameters ◽  
Parameter Approach

Abstract We propose a novel multi-parameter approach for conducting seismic hazard sensitivity analysis. This approach allows one to assess the importance of each input parameter at a variety of settings of the other input parameters and thus provides a much richer picture than standard analyses, which assess each input parameter only at the default settings of the other parameters. We illustrate our method with a sensitivity analysis of seismic hazard for Jerusalem. In this example, we find several input parameters whose importance depends critically on the settings of other input parameters. This phenomenon, which cannot be detected by a standard sensitivity analysis, is easily diagnosed by our method. The multi-parameter approach can also be used in the context of a probabilistic assessment of seismic hazard that incorporates subjective probability distributions for the input parameters.

scholarly journals Quantifying the Errors Involved in Transferring Suspended Sediment Rating Equations Across Ablation Seasons

1989 ◽  
Vol 13 ◽  
pp. 64-68 ◽  
Author(s):  
C.R. Fenn
Keyword(s):  
Transfer Function ◽  
Regression Model ◽  
Suspended Sediment ◽  
Simple Structure ◽  
Transfer Functions ◽  
Poor Performance ◽  
Generalized Least Squares ◽  
The Other ◽  
The Poor ◽  
Suspended Loads

Bias-corrected suspended sediment rating equations are developed for the data from six separate ablation seasons in the Glacier de Tsidjiore Nouve basin. These equations differ significantly from one another. Suspended loads as predicted by equations used beyond their year of origin fall in the range of 34-278% of the true load. Mean absolute-percentage errors (MAPE) based on forecasts computed from each year’s model applied to the other 5 years of data range from 35 to 81%, with a mean of 52%. The equivalent MAPE for a lumped multi-year model is 38%, for an autocorrelation-correcting generalized least-squares (GLS) regression model, is 15%, and for a transfer function (TF) developed from a single 25 d period, only 5%. Simple structure-transfer functions appear to be more robust to temporal transfer than the usual type of rating equation, and offer the possibility of greatly improving upon the poor performance of OLS rating equations in providing estimates of suspended loads for periods beyond frames of origin.

On the wind resource in Algeria: Probability distributions evaluation

2020 ◽  
pp. 095765092097588
Author(s):  
Houdayfa Ounis ◽  
Nawel Aries
Keyword(s):  
Wind Speed ◽  
Probability Distribution ◽  
Probability Distributions ◽  
Resource Assessment ◽  
Descriptive Statistics ◽  
The Other ◽  
Wind Speeds ◽  
Wind Resource Assessment ◽  
The Mean ◽  
Wind Resource

The present study aims to present a contribution to the wind resource assessment in Algeria using ERA-Interim reanalysis. Firstly, the ERA-Interim reanalysis 10 m wind speed data are considered for the elaboration of the mean annual 10 m wind speed map for a period starting from 01-01-2000 to 31-12-2017. Moreover, the present study intends to highlight the importance of the descriptive statistics other than the mean in wind resource assessment. On the other hand, this study aims also to select the proper probability distribution for the wind resource assessment in Algeria. Therefore, nine probability distributions were considered, namely: Weibull, Gamma, Inverse Gaussian, Log Normal, Gumbel, Generalized Extreme Value (GEV), Nakagami, Generalized Logistic and Pearson III. Furthermore, in combination with the distribution, three parameter estimation methods were considered, namely, Method of Moment, Maximum Likelihood Method and L-Moment Method. The study showed that Algeria has several wind behaviours due to the diversified topographic, geographic and climatic properties. Moreover, the annual mean 10 m wind speed map showed that the wind speed varies from 2.3 to 5.3 m/s, where 73% of the wind speeds are above 3 m/s. The map also showed that the Algerian Sahara is windiest region, while, the northern fringe envelopes the lowest wind speeds. In addition, it has been shown that the study of the mean wind speeds for the evaluation of the wind potential alone is not enough, and other descriptive statistics must be considered. On the other hand, among the nine considered distribution, it appears that the GEV is the most appropriate probability distribution. Whereas, the Weibull distribution showed its performance only in regions with high wind speeds, which, implies that this probability distribution should not be generalized in the study of the wind speed in Algeria.

scholarly journals Statistical Aspects of Wasserstein Distances

2019 ◽  
Vol 6 (1) ◽  
pp. 405-431 ◽  
Author(s):  
Victor M. Panaretos ◽  
Yoav Zemel
Keyword(s):  
Probability Distributions ◽  
The Other ◽  
Mass Transportation ◽  
Complex Objects ◽  
Convergence Of Moments ◽  
Natural Notion ◽  
Versatile Tool ◽  
Probability Mass ◽  
Minimal Effort ◽  
Wasserstein Distances

Wasserstein distances are metrics on probability distributions inspired by the problem of optimal mass transportation. Roughly speaking, they measure the minimal effort required to reconfigure the probability mass of one distribution in order to recover the other distribution. They are ubiquitous in mathematics, with a long history that has seen them catalyze core developments in analysis, optimization, and probability. Beyond their intrinsic mathematical richness, they possess attractive features that make them a versatile tool for the statistician: They can be used to derive weak convergence and convergence of moments, and can be easily bounded; they are well-adapted to quantify a natural notion of perturbation of a probability distribution; and they seamlessly incorporate the geometry of the domain of the distributions in question, thus being useful for contrasting complex objects. Consequently, they frequently appear in the development of statistical theory and inferential methodology, and they have recently become an object of inference in themselves. In this review, we provide a snapshot of the main concepts involved in Wasserstein distances and optimal transportation, and a succinct overview of some of their many statistical aspects.

Schrödinger-Iike equations for spin measurements, states, and wave functions, based on the statistical approach of Guiasu

1994 ◽  
Vol 72 (3-4) ◽  
pp. 130-133
Author(s):  
Paul B. Slater
Keyword(s):  
Statistical Estimation ◽  
Statistical Approach ◽  
Probability Distributions ◽  
Wave Functions ◽  
The Other ◽  
Weight Functions ◽  
Information Theoretic ◽  
Mixed Spin ◽  
Spin Measurements ◽  
Schrödinger Form

Guiasu employed a statistical estimation principle to derive time-independent Schrödinger equations for the position but, as is usual, not the spin of a particle. Here, on the other hand, this principle is used to obtain Schrödinger-like equations for the spin but not the position of a particle. Steady states are described by continuous probability distributions, obtained by information-theoretic arguments, over spin measurements, states, and wave functions. These distributions serve as weight functions for orthogonal polynomials. Associated "wave functions," products of the polynomials and the square root of the weight function, satisfy differential equations, reducing to time-independent Schrödinger form at the point corresponding to the fully mixed spin-1/2 state.

Hominid cranial capacity versus time: A regression approach

1973 ◽  
Vol 2 (5) ◽  
pp. 405-411 ◽  
Author(s):  
Pete E. Lestrel ◽  
Dwight W. Read
Keyword(s):  
Cranial Capacity ◽  
Regression Approach

Probability Distributions of Vertical Bending Moments on a FPSO in Abnormal Wave Seastates

2007 ◽  
Author(s):  
Nuno Fonseca ◽  
Ricardo Pascoal ◽  
Carlos Guedes Soares
Keyword(s):  
Probability Distributions ◽  
The Other ◽  
Wave Crest ◽  
Large Set ◽  
Bending Moments ◽  
Wave Groups ◽  
Wave Elevation ◽  
Other Hand

A method to calculate the responses of a FPSO in deterministic wave traces with abnormal waves, has been applied to calculate the motions and global structural loads induced by a large set of abnormal waves that were measured in different places. The present paper is focused on the probability distributions of the motions and global structural loads induced by the seastates which included the abovementioned abnormal waves. The objective is to compare the distributions of the wave elevation with the abnormal wave crest and trough, and to compare the distributions of the platform responses with the responses induced by the abnormal waves. In this way it is possible to conclude if the abnormal waves induce abnormal responses of the platform, or if on the other hand there are wave groups with waves smaller than the abnormal wave that induce larger responses.

scholarly journals Quantifying the Errors Involved in Transferring Suspended Sediment Rating Equations Across Ablation Seasons

1989 ◽  
Vol 13 ◽  
pp. 64-68
Author(s):  
C.R. Fenn
Keyword(s):  
Transfer Function ◽  
Regression Model ◽  
Suspended Sediment ◽  
Simple Structure ◽  
Transfer Functions ◽  
Poor Performance ◽  
Generalized Least Squares ◽  
The Other ◽  
The Poor ◽  
Suspended Loads

Bias-corrected suspended sediment rating equations are developed for the data from six separate ablation seasons in the Glacier de Tsidjiore Nouve basin. These equations differ significantly from one another. Suspended loads as predicted by equations used beyond their year of origin fall in the range of 34-278% of the true load. Mean absolute-percentage errors (MAPE) based on forecasts computed from each year’s model applied to the other 5 years of data range from 35 to 81%, with a mean of 52%. The equivalent MAPE for a lumped multi-year model is 38%, for an autocorrelation-correcting generalized least-squares (GLS) regression model, is 15%, and for a transfer function (TF) developed from a single 25 d period, only 5%. Simple structure-transfer functions appear to be more robust to temporal transfer than the usual type of rating equation, and offer the possibility of greatly improving upon the poor performance of OLS rating equations in providing estimates of suspended loads for periods beyond frames of origin.

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