705,067 research outputs found
Real-time state of charge estimation of electrochemical model for lithium-ion battery
This paper proposes the real-time Kalman filter based observer for Lithium-ion concentration estimation for the electrochemical battery model. Since the computation limitation of real-time battery management system (BMS) micro-processor, the battery model which is utilized in observer has been further simplified. In this paper, the Kalman filter based observer is applied on a reduced order model of single particle model to reduce computational burden for real-time applications. Both solid phase surface lithium concentration and battery state of charge (SoC) can be estimated with real-time capability. Software simulation results and the availability comparison of observers in different Hardware-in- the-loop simulation setups demonstrate the performance of the proposed method in state estimation and real-time application
Multi-Estimator Full Left Ventricle Quantification through Ensemble Learning
Cardiovascular disease accounts for 1 in every 4 deaths in United States.
Accurate estimation of structural and functional cardiac parameters is crucial
for both diagnosis and disease management. In this work, we develop an ensemble
learning framework for more accurate and robust left ventricle (LV)
quantification. The framework combines two 1st-level modules: direct estimation
module and a segmentation module. The direct estimation module utilizes
Convolutional Neural Network (CNN) to achieve end-to-end quantification. The
CNN is trained by taking 2D cardiac images as input and cardiac parameters as
output. The segmentation module utilizes a U-Net architecture for obtaining
pixel-wise prediction of the epicardium and endocardium of LV from the
background. The binary U-Net output is then analyzed by a separate CNN for
estimating the cardiac parameters. We then employ linear regression between the
1st-level predictor and ground truth to learn a 2nd-level predictor that
ensembles the results from 1st-level modules for the final estimation.
Preliminary results by testing the proposed framework on the LVQuan18 dataset
show superior performance of the ensemble learning model over the two base
modules.Comment: Jiasha Liu, Xiang Li and Hui Ren contribute equally to this wor
Estimating Abundance from Counts in Large Data Sets of Irregularly-Spaced Plots using Spatial Basis Functions
Monitoring plant and animal populations is an important goal for both
academic research and management of natural resources. Successful management of
populations often depends on obtaining estimates of their mean or total over a
region. The basic problem considered in this paper is the estimation of a total
from a sample of plots containing count data, but the plot placements are
spatially irregular and non randomized. Our application had counts from
thousands of irregularly-spaced aerial photo images. We used change-of-support
methods to model counts in images as a realization of an inhomogeneous Poisson
process that used spatial basis functions to model the spatial intensity
surface. The method was very fast and took only a few seconds for thousands of
images. The fitted intensity surface was integrated to provide an estimate from
all unsampled areas, which is added to the observed counts. The proposed method
also provides a finite area correction factor to variance estimation. The
intensity surface from an inhomogeneous Poisson process tends to be too smooth
for locally clustered points, typical of animal distributions, so we introduce
several new overdispersion estimators due to poor performance of the classic
one. We used simulated data to examine estimation bias and to investigate
several variance estimators with overdispersion. A real example is given of
harbor seal counts from aerial surveys in an Alaskan glacial fjord.Comment: 37 pages, 7 figures, 4 tables, keywords: sampling, change-of-support,
spatial point processes, intensity function, random effects, Poisson process,
overdispersio
Competency assessment : integrating COCOMO II and people-CMM for estimation improvement
"Human factor" is one of the most relevant and crucial aspects of software development projects management. Aiming at the performance improvement for software processes in organizations, a new model has been developed to diagnose people related processes. This new model is People-CMM and represents a complementary solution to CMM. On the other hand, existing estimation models in Software Engineering perfectly integrate those aspects related to personnel’s technical and general competence, but fail to integrate competence and performance measurement instruments when it comes to determine the precise value for each of the factors involved in the estimation process. After reviewing the already deployed initiatives and recommendations for competence measurement in the industrial environment and the most relevant estimation methods for personnel factors used in software development projects, this article presents a recommendation for the integration of each of the "human factor" related metrics in COCOMO II with the management tools proposed by People-CMM, which are widely implemented by existing commercial tools.Publicad
Portfolio management with cryptocurrencies: the role of estimation risk
This paper contributes to the literature on cryptocurrencies, portfolio management and estimation risk by comparing the performance of naïve diversification, Markowitz diversification and the advanced Black–Litterman model with VBCs that controls for estimation errors in a portfolio of cryptocurrencies. We show that the advanced Black–Litterman model with VBCs yields superior out-of-sample risk-adjusted returns as well as lower risks. Our results are robust to the inclusion of transaction costs and short-selling, indicating that sophisticated portfolio techniques that control for estimation errors are preferred when managing cryptocurrency portfolios
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