Search results for "estimation"

On the sign recovery by LASSO, thresholded LASSO and thresholded Basis Pursuit Denoising

2020

Basis Pursuit (BP), Basis Pursuit DeNoising (BPDN), and LASSO are popular methods for identifyingimportant predictors in the high-dimensional linear regression model Y = Xβ + ε. By definition, whenε = 0, BP uniquely recovers β when Xβ = Xb and β different than b implies L1 norm of β is smaller than the L1 norm of b (identifiability condition). Furthermore, LASSO can recover the sign of β only under a much stronger irrepresentability condition. Meanwhile, it is known that the model selection properties of LASSO can be improved by hard-thresholdingits estimates. This article supports these findings by proving that thresholded LASSO, thresholded BPDNand thresholded BP recover the sign of β in …

Three Essays in Microeconometrics

2020

This dissertation examines three distinct issues using microeconometric techniques. The first two chapters fall in the realm of discrete choice models and try to make allowance for limited attention. The third chapter focuses on firm behavior and investigates the impact of ownership concentration on productivity. Chapter 1 predominantly builds on the consideration capacity model in Dardanoni, Manzini, Mariotti and Tyson (2019). In the attempt to behavioralize rational choice theory, their model identifies the distribution of cognitive characteristics in a population of agents who are observed choosing repeatedly from a single menu. By exploiting algebraic arguments, we first generalize the …

Modelling, Simulation and Characterization of a Supercapacitor in Automotive Applications

2020

The energy storage is one of the most discussed topics among Electrical Vehicles (EVs) research. Currently, supercapacitors (SCs) are collecting even more attention due to their unique features such as high-power density, high life cycle and lack of maintenance. In this paper, a supercapacitor model suitable for the simulation in automotive applications is identified. The model parameters are estimated and used to simulate the behaviour of a commercial SCs bank in different operating conditions. The model is finally validated considering experimental results.

Applications of Kernel Methods

2009

In this chapter, we give a survey of applications of the kernel methods introduced in the previous chapter. We focus on different application domains that are particularly active in both direct application of well-known kernel methods, and in new algorithmic developments suited to a particular problem. In particular, we consider the following application fields: biomedical engineering (comprising both biological signal processing and bioinformatics), communications, signal, speech and image processing.

Entire reflective object surface structure understanding based on reflection motion estimation

2015

An sub-segmentation method for the reflective surface structure understanding.The use of reflection motion features as spatiotemporal coherence for video segmentation.Straightforward implementation.A building block for object recognition. The presence of reflection on a surface has been a long-standing problem for object recognition since it brings negative effects on object's color, texture and structural information. Because of that, it is not a trivial task to recognize the surface structure affected by the reflection, especially when the object is entirely reflective. Most of the cases, reflection is considered as noise. In this paper, we propose a novel method for entire reflective obj…

The instability of the adjusted and unadjusted environmental Kuznets curves

2006

We test the stability of the unadjusted and adjusted environmental Kuznets curves (EKCs). Our results provide evidence in favour of a theoretically funded "adjusted EKC hypothesis" in which the impact of per capita GDP on CO2 emissions is evaluated conditionally to the effects of the industry mix and of the energy-supply infrastructure. In this specification, the shape of the GDP-CO2 relationship appears quite sensitive to changes in the estimation period. In the final part of the paper, signs and dynamics of fixed effects of individual countries in different specifications are interpreted as measures of virtuous or vicious of environmental behaviour. © 2006 Elsevier B.V. All rights reserve…

How to Deal with Systematic Uncertainties

2013

Soil Physical Quality of Citrus Orchards Under Tillage, Herbicide, and Organic Managements

2018

Abstract Soil capacity to support life and to produce economic goods and services is strongly linked to the maintenance of good soil physical quality (SPQ). In this study, the SPQ of citrus orchards was assessed under three different soil managements, namely no-tillage using herbicides, tillage under chemical farming, and no-tillage under organic farming. Commonly used indicators, such as soil bulk density, organic carbon content, and structural stability index, were considered in conjunction with capacitive indicators estimated by the Beerkan estimation of soil transfer parameter (BEST) method. The measurements taken at the L'Alcoleja Experimental Station in Spain yielded optimal values fo…

Development of a High Irradiance LED Configuration for Small Field of View Motion Estimation of Fertilizer Particles

2015

International audience; Better characterization of the fertilizer spreading process, especially the fertilizer pattern distribution on the ground, requires an accurate measurement of individual particle properties and dynamics. Both 2D and 3D high speed imaging techniques have been developed for this purpose. To maximize the accuracy of the predictions, a specific illumination level is required. This paper describes the development of a high irradiance LED system for high speed motion estimation of fertilizer particles. A spectral sensitivity factor was used to select the optimal LED in relation to the used camera from a range of commercially available high power LEDs. A multiple objective …

High Speed Stereovision Setup for Position and Motion Estimation of Fertilizer Particles Leaving a Centrifugal Spreader

2014

EA SPE GEAPSI; International audience; A 3D imaging technique using a high speed binocular stereovision system was developed in combination with corresponding image processing algorithms for accurate determination of the parameters of particles leaving the spinning disks of centrifugal fertilizer spreaders. Validation of the stereo-matching algorithm using a virtual 3D stereovision simulator indicated an error of less than 2 pixels for 90% of the particles. The setup was validated using the cylindrical spread pattern of an experimental spreader. A 2D correlation coefficient of 90% and a Relative Error of 27% was found between the experimental results and the (simulated) spread pattern obtai…