Search results for " estimation"
showing 10 items of 562 documents
What makes a citrus farmer go 'organic'? Empirical evidence from Spanish citrus farming
2012
Organic farming is increasing its share of total world food output and receiving grow-ing support from policymakers concerned with agricultural sustainability issues. This paper studies the characteristics of citrus farmers in the Spanish region of Valencia that affect their probability of becoming organic farmers. A fair understanding of these characteristics may help policymakers improve the design of agricultural policies aimed at supporting organic citrus practices. As regards the methodology, a probit model is estimated with information from a sample of conventional and organic citrus farmers obtained from a survey designed for a larger research project aimed at analysing Valencian cit…
Optimization of Delayed-State Kalman-Filter-based Algorithm via Differential Evolution for Sensorless Control of Induction Motors
2010
This paper proposes the employment of the differential evolution (DE) to offline optimize the covariance matrices of a new reduced delayed-state Kalman-filter (DSKF)-based algorithm which estimates the stator-flux linkage components, in the stationary reference frame, to realize sensorless control of induction motors (IMs). The DSKF-based algorithm uses the derivatives of the stator-flux components as mathematical model and the stator-voltage equations as observation model so that only a vector of four variables has to be offline optimized. Numerical results, carried out using a low-speed training test, show that the proposed DE-based approach is very promising and clearly outperforms a cla…
Flexible space-time process for seismic data
2009
Point processes are well studied objects in probability theory and a powerful tool in statistics for modelling and analyzing the distribution of real phenomena, such as the seismic one. Point processes can be specified mathematically in several ways, for instance, by considering the joint distributions of the counts of points in arbitrary sets or defining a complete intensity function. The conditional intensity function is a function of the point history and it is itself a stochastic process depending on the past up to time t. In this paper some techniques to estimate the intensity function of space-time point processes are developed, by following semi-parametric approaches and diagnostic m…
Central limit theorem for bifurcating Markov chains under L 2 -ergodic conditions
2021
Bifurcating Markov chains (BMC) are Markov chains indexed by a full binary tree representing the evolution of a trait along a population where each individual has two children. We provide a central limit theorem for additive functionals of BMC under L 2-ergodic conditions with three different regimes. This completes the pointwise approach developed in a previous work. As application, we study the elementary case of symmetric bifurcating autoregressive process, which justify the non-trivial hypothesis considered on the kernel transition of the BMC. We illustrate in this example the phase transition observed in the fluctuations.
Two-step cross correlation-based algorithm for motion estimation applied to fertilizer granules' motion during centrifugal spreading
2011
Imaging systems are progressing in both accuracy and ro- bustness, and their use in precision agriculture is increasing accordingly. One application of imaging systems is to understand and control the cen- trifugal fertilizing spreading process. Predicting the spreading pattern on the ground relies on an estimation of the trajectories and velocities of ejected granules. The algorithms proposed to date have shown low ac- curacy, with an error rate of a few pixels. But a more accurate estimation of the motion of the granules can be achieved. Our new two-step cross- correlation-based algorithm is based on the technique used in particle image velocimetry (PIV), which has yielded highly accurate…
L'évolution de l'occupation humaine : l'analyse spatiale exploratoire des données.Le problème de l'incertitude et de l'hétérogénéité des données en a…
2011
The analysis of the evolution of the settlement requires a lot of methodological questioning. Despite a frequent use of the spatial analysis methods, few works return to their methodological problems. This article proposes to make a comparison and a discussion around two exploratory statistical methods (the K function of Ripley and the Kernel Density Estimation). It seems that scale, quality and quantity of input data, are three essential parameters to be taken into account so as to lead a spatial analysis in archaeology. In intrinsic way, archaeological data are non homogeneous. For that purpose, our article proposes a multi scalar approach integrating the non homogeneousness character of …
A deep learning segmentation approach to calories and weight estimation of food images
2019
Master's thesis Information- and communication technology IKT590 - University of Agder 2019 Today’s generation is very aware of what they are eating and the amountof calories in their food. Eating too many calories can lead to increasedweight, which has become a big health issue. A study from 2016 states thatmore than 1,9 billion adults are overweight where almost one third of theseare obese. Statistics from Norway show that 1 of 4 men and 1 of 5 womenare obese.Artificial Intelligence in general and deep learning in particular can be usedto help understand the content of eaten food. In this master thesis, wepropose a network to estimate the weight of food from a single image. Thisis done in…
An Information Systems Design Product Theory for Software Project Estimation and Measurement Systems
2009
There is relatively little research on software Project Estimation and Measurement Systems (PEMS). Commercial PEMS vary in functionality and effectiveness. Their intended users thus do not know what to expect from PEMS and how to evaluate them. This paper creates an information system design product theory for the class of PEMS that prescribes the meta-requirements, the meta-design, and applicable theories for all products within the class. Meta-requirements and the meta-design are derived from the project estimation and measurement literature, experiences obtained during more than ten years of empirical work in Finnish Software Measurement Association, and a commercially available PEMS.
Automatic social distance estimation for photographic studies: Performance evaluation, test benchmark, and algorithm
2022
The social distancing regulations introduced to slow down the spread of COVID-19 virus directly affect a basic form of non-verbal communication, and there may be longer term impacts on human behavior and culture that remain to be analyzed in proxemics studies. To obtain quantitative results for such studies, large media and/or personal photo collections must be analyzed. Several social distance monitoring methods have been proposed for safety purposes, but they are not directly applicable to general photo collections with large variations in the imaging setup. In such studies, the interest shifts from safety to analyzing subtle differences in social distances. Currently, there is no suitabl…
Effets de quartier, effet de département : discrimination liée au lieu de résidence et accès à l'emploi
2013
L’objet de cette étude est de mesurer la discrimination à l’embauche à l’encontre des jeunes en Ile-de-France en raison du lieu de résidence en considérant plusieurs échelles spatiales de façon à distinguer l’effet de la réputation du département (Paris et la Seine-Saint-Denis), celui de la localité et celui du quartier. L’évaluation est réalisée sur données expérimentales auto-construites de testing selon un protocole permettant d’examiner les effets propres à chacune de ces trois échelles sur l’accès à l’emploi ainsi que leurs effets cumulés. On s’intéresse aux discriminations pour deux professions en tension du secteur de la restauration pour laquelle les discriminations devraient a prio…