scholarly journals Application of robust estimation methods to simple models of nucleon separation energies

2015 ◽  
Vol 30 (24) ◽  
pp. 1550121
Author(s):  
S. Baselga
Keyword(s):  
Least Squares ◽  
Robust Estimation ◽  
Estimation Methods ◽  
Quality Of Data ◽  
Estimated Parameters ◽  
Complex Models ◽  
The Stability ◽  
Experimental Values ◽  
Simple Models

Some works have recently shown the usefulness of simple models of nucleon separation energies in terms of neutron and proton numbers. However, the customary use of least squares in the process of parameter estimation turns out to be extremely sensible to the accuracy of the model and the extent and quality of data (e.g. highly vulnerable to the sample size or the possible existence of undesired errors in the experimental values). We will show how robust estimation by global optimization instead of least squares estimation improves on both the stability of the estimated parameters and the extrapolation to unknown energies. Comparison against recently determined experimental data will show a level of agreement comparable to the predictions made by the best and much more complex models.

scholarly journals Application of Robust Estimation Methods for the Analysis of Outlier Measurements / Aplikácia Robustných Odhadovacích Metód Pri Analýze Odľahlých Meraní

2011 ◽  
Vol 57 (3) ◽  
pp. 14-29
Author(s):  
Silvia Gašincová ◽  
Juraj Gašinec ◽  
Gabriel Weiss ◽  
Slavomír Labant
Keyword(s):  
Linear Programming ◽  
Least Squares ◽  
Robust Estimation ◽  
Mathematical Analysis ◽  
Physical Environment ◽  
Regression Line ◽  
Measured Data ◽  
Estimation Methods ◽  
Method Of Least Squares ◽  
The Impact

Abstract The basis of mathematical analysis of geodetic measurements is the method of least squares (LSM), whose bicentenary we celebrated in 2006. In geodetic practice, we quite often encounter the phenomenon when outlier measurements penetrate into the set of measured data as a result of e.g. the impact of physical environment. That fact led to modifications of LSM that have been increasingly published mainly in foreign literature in recent years. The mentioned alternative estimation methods are e.g. robust estimation methods and methods in linear programming. The aim of the present paper is to compare LSM with the robust estimation methods on an example of a regression line.

scholarly journals Application of Diversity Combining with RLS Adaptive Filtering in Data Transmission in a Hydroacoustic Channel

Sensors ◽  
2020 ◽  
Vol 20 (24) ◽  
pp. 7255
Author(s):  
Agnieszka Czapiewska ◽  
Andrzej Luksza ◽  
Ryszard Studanski ◽  
Andrzej Zak
Keyword(s):  
Least Squares ◽  
Adaptive Filtering ◽  
Data Transmission ◽  
Intersymbol Interference ◽  
Multipath Propagation ◽  
Recursive Least Squares ◽  
Diversity Combining ◽  
Quality Of Data ◽  
Transmission Parameters

When transmitting data in a hydroacoustic channel under difficult propagation conditions, one of the problems is intersymbol interference (ISI) caused mainly by the effect of multipath propagation. This phenomenon leads to a decrease in transmission parameters, and sometimes completely prevents it. Therefore, we have made an attempt to use diversity combining with Recursive Least Squares (RLS) adaptive filtering to improve the quality of data transmission in a hydroacoustic channel with strong reflections. The method was tested in simulation and during measurements in a real environment. The influence of the method on data transmission in the hydroacoustic channel was examined in detail. The obtained results allow us to draw conclusions regarding the purposefulness of use of diversity combining and RLS adaptive filtering in order to improve the quality of data transmission by reducing the effect of ISI.

Flow and Temperature Analysis of Molten Pool in Twin-Roll Strip Casting Process

2007 ◽  
Vol 340-341 ◽  
pp. 695-700 ◽  
Author(s):  
Xiao Ming Zhang ◽  
Zheng Yi Jiang ◽  
L.M. Yang ◽  
Xiang Hua Liu ◽  
Guo Dong Wang
Keyword(s):  
Molten Pool ◽  
Metal Flow ◽  
Casting Process ◽  
Strip Casting ◽  
Roll Casting ◽  
Quality Of Products ◽  
The Stability ◽  
Experimental Values ◽  
Twin Roll

In twin-roll strip casting process, metal flow and temperature distribution in the molten pool directly affect the stability of the process and the quality of products. In this paper, a 3D coupling temperature-flow finite element simulation during twin-roll strip casting has been carried out, and the influences of the outlet angle and the submerged depth on the temperature and flow fields in the molten pool were investigated for the twin-roll casting of stainless steel. An inverse method was used to determine the boundary conditions between the roll and molten pool. Simulation results are consistent with the experimental values. Numerical simulation is helpful to optimise the twin-roll strip casting process and to improve the quality of products in practice.

scholarly journals STUDY OF THE ALGORITHM OF PSEUDONORMAL OPTIMIZATION ON THE STABILITY OF THE SOLUTION OF THE EQUATION PROBLEM AND THE ESTIMATION OF THE ACCURACY

2021 ◽  
Vol 1 ◽  
pp. 40-48
Author(s):  
Amridon G. Barliani ◽  
Galina A. Nefedova ◽  
Irina V. Karnetova
Keyword(s):  
Least Squares ◽  
Least Squares Method ◽  
Experimental Studies ◽  
Network Models ◽  
Optimization Method ◽  
Equation Problem ◽  
Estimated Parameters ◽  
The Matrix ◽  
The Stability ◽  
Stability Of The Solution

In geodesic practice, when designing and adjusting geodetic networks for various purposes on a computer, it is necessary to solve poorly conditioned systems of linear normal equations. In such systems, the determinant of the matrix of equations tends to zero, so the application of the least squares method leads to large distortions of the estimated parameters. Moreover, in such situations, for the least squares algorithm, a slight distortion of the input data leads to unacceptably large distortions of the final results of the equalization and accuracy estimation. In this regard, the application of the pseudonormal optimization method is proposed. The presented work is devoted to the study of the stability of the solution of the adjustment task and the estimation of accuracy obtained on the basis of the pseudonormal optimization method. The novelty is the obtained algorithm for estimating the relative error of the pseudonormal optimization method. A comparative analysis of two competing processing methods was performed for different network models. The results of experimental studies and their analysis have shown the advantage of the pseudonormal optimization method over the least squares method.

Least-squares decomposition with time–space constraint for denoising microseismic data

2020 ◽  
Vol 222 (3) ◽  
pp. 1864-1880
Author(s):  
Yangkang Chen ◽  
Wei Chen ◽  
Yufeng Wang ◽  
Min Bai
Keyword(s):  
Least Squares ◽  
Signal To Noise Ratio ◽  
Random Noise ◽  
Microseismic Data ◽  
Smoothness Constraint ◽  
Time Space ◽  
Wide Range ◽  
The Stability ◽  
And Inversion

SUMMARY Microseismic data are usually of low signal-to-noise ratio (SNR), which makes it difficult to utilize the microseismic waveforms for imaging and inversion. We develop a useful denoising algorithm based on a non-stationary least-squares decomposition model to enhance the quality of microseismic signals. The microseismic signals are assumed to be represented by a superposition of several smoothly variable components. We construct a least-squares inverse problem to solve for the the smooth components. We constrain the least-squares inversion via both time and space constraints. The temporal smoothness constraint is applied to ensure the stability when calculating the non-stationary autoregression coefficients. The space-smoothness constraint is applied to extract the spatial correlation among multichannel microseismic traces. The new algorithm is validated via several synthetic and real microseismic data and are proved to be effective. Comparison with the state-of-the-art algorithms demonstrates that the proposed method is more powerful in suppressing random noise of a wide range of levels than its competing methods.

scholarly journals DETERMINING THE OPTIMAL DIMENSIONS FOR A MECHANISM FROM A WHEELCHAIR USING LABVIEW

2018 ◽  
Vol 6 (1) ◽  
pp. 240-247
Author(s):  
Vlad Gheorghita ◽  
Catalin Gheorghita
Keyword(s):  
Development Process ◽  
Product Development Process ◽  
Improve Performance ◽  
Software Model ◽  
Design Changes ◽  
Optimum Selection ◽  
The Stability ◽  
Experimental Values ◽  
Selection Of

The optimum selection of process parameters plays a very important role to ensure quality of product, to reduce the machining cost and to increase the productivity. Customizing a product to improve performance requires a reliable method to measure performance, in order to evaluate the effects that design changes have on them. A product development process can be thought as a sequence of activities to be completed. This paper has the purpope to analyse the influence of the parameters for equipment from a wheelchair that will overcome obstacles. The fuzzy logic is used through specialized software to optimize several parameters of the proposed mechanism with the purpose to ensure the stability through maintaining horizontality of the equipment. Comparing experimental values with those obtained through the software model, is determined whether the model used is consistent.

Modeling Uncertainty Based on Spatial Models in Spreading Diseases

2019 ◽  
Vol 8 (4) ◽  
pp. 55-66
Author(s):  
Stelios Zimeras ◽  
Yiannis G. Matsinos
Keyword(s):  
Spatial Models ◽  
High Dimensionality ◽  
Main Task ◽  
Quality Of Data ◽  
Statistical Tool ◽  
Modeling Uncertainty ◽  
Window Method ◽  
Hierarchical Levels ◽  
Complex Models

Lately, spatial models have become a powerful, necessary statistical tool to estimate parameters where data are represented by regions of interests using the window method . Estimation processes based on the high dimensionality of the data have become difficult to implement especially in cases where variability in the spatial models is the main task to investigate. Variability between spatial models considering hierarchical levels of scale, most of the time, involves errors leading to uncertainty in spatial regions. Solving the problem with uncertainty via the estimation of errors in spatial models, complex models could be simplified in easiest ones and important decisions for the quality of data could be taken.

scholarly journals The influence of the shock absorber type on the stability of an ambulance vehicle to the rolls of its spring-suspended weight

2021 ◽  
Vol 18 (1) ◽  
pp. 133-139
Author(s):  
V. N. Dobromirov ◽  
◽  
A. M. Voytko ◽  
Keyword(s):  
Angular Acceleration ◽  
Vehicle Suspension ◽  
Shock Absorbers ◽  
Estimated Parameters ◽  
Air Suspension ◽  
Road Testing ◽  
The Stability ◽  
Seriously Ill ◽  
Pneumatic Shock

The article presents the results of assessing the stability of the ambulance vehicle to lateral and longitudinal rolls regarding them as parameters affecting the quality of health care to the transported victim. The authors present the results of a road testing aimed at assessing the vehicle resistance to such rolls under conditions of imitation of a seriously ill patient`s delivery to a medical institution. The tests were carried out on ambulances equipped on the basis of Ford Transit vehicles, using various types of damping elements in the suspension, namely, two variants of two-tube hydraulic shock absorbers; one-tube hydro-pneumatic shock absorbers; air suspension. As the estimated parameters, there were used the values of actual angular acceleration of the passenger compartment rolls in comparison with the values admissible for medical indicators. It is shown that from the standpoint of providing the best comfort for the patient and the medical crew of ambulance, it is preferable to use in the vehicle suspension the single-tube hydro-pneumatic shock absorbers, the installation of which is permissible under conditions of operational modernization of the vehicle.

Methods to Monitor and Improve the Performance of Specimen Holders for Transmission Electron Cryomicroscopy

1996 ◽  
Vol 54 ◽  
pp. 454-455
Author(s):  
B. L. Armbruster ◽  
B. Kraus ◽  
M. Pan
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
Electron Beam Irradiation ◽  
Beam Irradiation ◽  
Quality Of Data ◽  
Electron Cryomicroscopy ◽  
Thermal Equilibration ◽  
Transmission Electron ◽  
Electron Microscopes

One goal in electron microscopy of biological specimens is to improve the quality of data to equal the resolution capabilities of modem transmission electron microscopes. Radiation damage and beam- induced movement caused by charging of the sample, low image contrast at high resolution, and sensitivity to external vibration and drift in side entry specimen holders limit the effective resolution one can achieve. Several methods have been developed to address these limitations: cryomethods are widely employed to preserve and stabilize specimens against some of the adverse effects of the vacuum and electron beam irradiation, spot-scan imaging reduces charging and associated beam-induced movement, and energy-filtered imaging removes the “fog” caused by inelastic scattering of electrons which is particularly pronounced in thick specimens.Although most cryoholders can easily achieve a 3.4Å resolution specification, information perpendicular to the goniometer axis may be degraded due to vibration. Absolute drift after mechanical and thermal equilibration as well as drift after movement of a holder may cause loss of resolution in any direction.

Criteria for evaluation of the coordinate measurements quality of parts geometric parameters at pilot-experimental production

2019 ◽  
pp. 3-8
Author(s):  
N.Yu. Bobrovskaya ◽  
M.F. Danilov
Keyword(s):  
Quality Indicators ◽  
Quality Management System ◽  
Technical Specification ◽  
Experimental Production ◽  
Technological Heredity ◽  
Coordinate Measurements ◽  
Reasonable Choice ◽  
The Stability ◽  
Geometric Elements

The criteria of the coordinate measurements quality at pilot-experimental production based on contemporary methods of quality management system and traditional methods of the measurements quality in Metrology are considered. As an additional criterion for quality of measurements, their duration is proposed. Analyzing the problem of assessing the quality of measurements, the authors pay particular attention to the role of technological heredity in the analysis of the sources of uncertainty of coordinate measurements, including not only the process of manufacturing the part, but all stages of the development of design and technological documentation. Along with such criteria as the degree of confidence in the results of measurements; the accuracy, convergence, reproducibility and speed of the results must take into account the correctness of technical specification, and such characteristics of the shape of the geometric elements to be controlled, such as flatness, roundness, cylindrical. It is noted that one of the main methods to reduce the uncertainty of coordinate measurements is to reduce the uncertainty in the initial data and measurement conditions, as well as to increase the stability of the tasks due to the reasonable choice of the basic geometric elements (measuring bases) of the part. A prerequisite for obtaining reliable quality indicators is a quantitative assessment of the conditions and organization of the measurement process. To plan and normalize the time of measurements, the authors propose to use analytical formulas, on the basis of which it is possible to perform quantitative analysis and optimization of quality indicators, including the speed of measurements.

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