Search results for "bias correction"

Calibrating Expert Assessments Using Hierarchical Gaussian Process Models

2020

Expert assessments are routinely used to inform management and other decision making. However, often these assessments contain considerable biases and uncertainties for which reason they should be calibrated if possible. Moreover, coherently combining multiple expert assessments into one estimate poses a long-standing problem in statistics since modeling expert knowledge is often difficult. Here, we present a hierarchical Bayesian model for expert calibration in a task of estimating a continuous univariate parameter. The model allows experts' biases to vary as a function of the true value of the parameter and according to the expert's background. We follow the fully Bayesian approach (the s…

Readability and the Web

2012

Readability indices measure how easy or difficult it is to read and comprehend a text. In this paper we look at the relation between readability indices and web documents from two different perspectives. On the one hand we analyse how to reliably measure the readability of web documents by applying content extraction techniques and incorporating a bias correction. On the other hand we investigate how web based corpus statistics can be used to measure readability in a novel and language independent way.

Refitting Solutions Promoted by $$\ell _{12}$$ Sparse Analysis Regularizations with Block Penalties

2019

International audience; In inverse problems, the use of an l(12) analysis regularizer induces a bias in the estimated solution. We propose a general refitting framework for removing this artifact while keeping information of interest contained in the biased solution. This is done through the use of refitting block penalties that only act on the co-support of the estimation. Based on an analysis of related works in the literature, we propose a new penalty that is well suited for refitting purposes. We also present an efficient algorithmic method to obtain the refitted solution along with the original (biased) solution for any convex refitting block penalty. Experiments illustrate the good be…

Volumetric Bias Correction

2007

This paper presents a method to suppress the bias artifact, also known as RF-inhomogeneity, in Magnetic Resonance Imaging (MRI). This artifact produces illumination variations due to magnetic field fluctuations of the device. In the latest years many works have been devoted to face this problem. In this work we present the 3D version of a new approach to bias correction, which is called Exponential Entropy Driven Homomorphic Unsharp Masking (E2D-HUM). This technique has been already presented by some of the authors for the 2D case only. The description of the whole method is detailed, and some experimental results are reported.

Effects of the European Monetary Union on High-Technology Exports

2021

AbstractOur study estimates the effects of the European Monetary Union (EMU) on high-technology (HT) export and assesses the potential knowledge spillovers of such trade. Irrespective of the importance of the HT trade channel, none of the previous studies in the literature focus on the effects of a common currency on HT trade. Increasing trade in the HT sector may lead to more efficient use of resources and help countries to move towards a knowledge-based economy. Moreover, it may lead to higher overall growth. After considering multilateral resistances, pair fixed effects and bias correction in the preferred (three-way bias-corrected) model, EMU membership becomes negative and statisticall…

Objective regional frequency analysis and future change of extreme precipitation in Sicily, Italy

Isotope fractionation of zinc in the paddy rice soil-water environment and the role of 2’deoxymugineic acid (DMA) as zincophore under Zn limiting con…

2021

Non-traditional stable isotope systems are increasingly used to study micronutrient cycling and acquisition in terrestrial ecosystems. We previously proposed for zinc (Zn) a conceptual model linking observed isotope signatures and fractionations to biogeochemical processes occurring in the rice soil environment and we suggested that 2’deoxymugineic acid (DMA) could play an important role for rice during the acquisition of Zn when grown under Zn limiting conditions. This proposition was sustained by the extent and direction of isotope fractionation observed during the complexation of Zn with DMA synthesised in our laboratory. Here we report a new set of experimental data from field and labor…

Combining a data-driven approach with seasonal forecast data to predict reservoir water volume in the Mediterranean area

2023

Prolonged droughts and water scarcity have become more frequent in recent years, exacerbating the problem of the artificial reservoirs management in the Mediterranean area. This study proposes a methodology which combines a Nonlinear AutoRegressive network with eXogenous input (NARX) data-driven model with Seasonal Forecasts (SFs) data, with the aim to predict the water volume stored in reservoirs at a mid-term scale, as requested by the local authority. The methodology is applied to four Sicilian reservoirs that experienced water scarcity in the recent past. SFs produced at the European Centre for Medium-Range Weather Forecasting are used to force the NARX models. Also, the reservoirs are …

Statistical downscaling method of regional climate model results for hydrological modelling

2009

Multiple Structured Light-Based Depth Sensors for Human Motion Analysis: A Review

2012

Human motion analysis is an increasingly important active research domain with various applications in surveillance, human-machine interaction and human posture analysis. The recent developments in depth sensor technology, especially with the release of the Kinect device, have attracted significant attention to the question of how to take advantage of this technology in order to achieve accurate motion tracking and action detection in marker-less approaches. In this paper, we review the benefits and limitations deriving from the adoption of structured light-based depth sensors in human motion analysis applications. Surveying the relevant literature, we have identified in calibration, interf…