scholarly journals Is the Best Fitting Curve Always Unique?

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
N. Chernov ◽  
Q. Huang ◽  
H. Ma
Keyword(s):  
Computer Vision ◽  
Errors In Variables ◽  
Basic Task ◽  
Data Points ◽  
Best Fitting ◽  
Straight Lines ◽  
Best Fit ◽  
Curved Objects

Fitting straight lines and simple curved objects (circles, ellipses, etc.) to observed data points is a basic task in computer vision and modern statistics (errors-in-variables regression). We have investigated the problem of existence of the best fit in our previous paper (see Chernov et al. (2012)). Here we deal with the issue of uniqueness of the best fit.

scholarly journals Does the Best-Fitting Curve Always Exist?

2012 ◽  
Vol 2012 ◽  
pp. 1-25 ◽  
Author(s):  
N. Chernov ◽  
Q. Huang ◽  
H. Ma
Keyword(s):  
Computer Vision ◽  
Errors In Variables ◽  
Geometric Shapes ◽  
Data Points ◽  
Best Fitting ◽  
Best Fit

Fitting geometric shapes to observed data points (images) is a popular task in computer vision and modern statistics (errors-in-variables regression). We investigate the problem of existence of the best fit using geometric and probabilistic approaches.

scholarly journals Identification-Robust Estimates of the Canadian Natural Rate of Interest

2016 ◽  
Vol 91 (1-2) ◽  
pp. 161-176
Author(s):  
Maral Kichian
Keyword(s):  
Interest Rate ◽  
Robust Methods ◽  
Errors In Variables ◽  
Natural Rate ◽  
Real Rate ◽  
Point Estimates ◽  
Natural Rate Of Interest ◽  
Best Fitting ◽  
Estimate Precision ◽  
Fitting Model

The natural rate of interest is an unobservable entity and its measurement presents some important empirical challenges. In this paper, we use identification-robust methods and central bank real-time staff projections to obtain estimates for the equilibrium real rate from contemporaneous and forward-looking Taylor-type interest rate rules. The methods notably account for the potential presence of endogeneity, under-identification, and errors-in-variables concerns. Our applications are conducted on Canadian data. The results reveal some important identification difficulties associated with some of our models, reinforcing the need to use identification-robust methods to estimate such policy functions. Despite these challenges, we are able to obtain fairly comparable point estimates for the real equilibrium interest rate across our different models, and in the case of the best fitting model, also remarkable estimate precision.

An Analysis of the Shape and Propagation of Waves on the Flagellum of Crithidia Oncopelti

1979 ◽  
Vol 80 (1) ◽  
pp. 299-315
Author(s):  
D. N. JOHNSTON ◽  
N. R. SILVESTER ◽  
M. E. J. HOLWILL
Keyword(s):  
Back Projection ◽  
Active Process ◽  
Automatic Data ◽  
Circular Arcs ◽  
Fourier Series Method ◽  
Dark Ground ◽  
Propagation Of Waves ◽  
Straight Lines ◽  
Best Fit ◽  
Automatic Data Acquisition

Ciné micrographs were taken of the flagellated protozoan Crithidia oncopelti under dark-ground illumination. Coordinates of images of the flagella were obtained from the ciné frames by back-projection and automatic data acquisition. The flagellar waveforms of proximally directed waves were characterized using a Fourier-series method and compared by this means with a number of analytical curves. The shape of a wave remained constant as it was propagated and, of the curves suggested, a wave consisting of circular arcs connected by straight lines gave the best fit. The variation of bend curvature as bends moved along the flagellum was also found, for both proximally and distally directed waves. The wavelengths and speeds of proximally directed waves increased linearly with distance as they approached the base of the flagellum, while in distally directed bends the curvature remained constant but the velocity increased as bends moved away from the base. Causes of the above behaviour are discussed and it is concluded from the variation of curvature with time for proximally directed flagellar waves that unbending must be an active process.

scholarly journals Using Analytic Tools with California School Library Survey Data

2015 ◽  
Vol 10 (2) ◽  
pp. 90
Author(s):  
Lesley Farmer ◽  
Alan Safer ◽  
Joanna Leack
Keyword(s):  
Survey Data ◽  
School Library ◽  
School Libraries ◽  
State Standards ◽  
Funding Sources ◽  
Library Resources ◽  
Data Points ◽  
Cart Algorithm ◽  
Best Fit ◽  
Standard Library

Abstract Objective — California school libraries have new state standards, which can serve to guide their programs. Based on pre-standard and post-standard library survey data, this research compares California school library programs to determine the variables that can potentially help a school library reach the state standards, and to develop a predictive model of those variables. Methods – Variations of decision trees and logistic regression statistical techniques were applied to the library survey data in order to create the best-fit model. Results – Best models were chosen within each technique, and then compared, concluding that the decision tree using the CART algorithm had the most accurate results. Numerous variables came up as important across different models, including: funding sources, collection size, and access to online subscriptions. Conclusion – School library metrics can help both librarians and the educational community analyze school library programs closely and determine effective ways to maximize the school library’s impact on student learning. More generally, library resources and services can be measured as data points, and then modeling statistics can be applied in order to optimize library operations.

scholarly journals Retrieving the True Masses of Gravitational Wave Sources

Proceedings ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 4 ◽  
Author(s):  
Xian Chen ◽  
Zhefeng Shen
Keyword(s):  
Hydrodynamic Drag ◽  
Chirp Signal ◽  
Binary Black Holes ◽  
Best Fitting ◽  
Real Mass ◽  
The Masses ◽  
The Impact ◽  
Best Fit ◽  
Gas Effect ◽  
Fitting Parameters

Gravitational waves (GWs) encode important information about the mass of the source. For binary black holes (BBHs), the templates that are used to retrieve the masses normally are developed under the assumption of a vacuum environment. However, theories suggest that some BBHs form in gas-rich environments. Here, we study the effect of hydrodynamic drag on the chirp signal of a stellar-mass BBH and the impact on the measurement of the mass. Based on theoretical arguments, we show that the waveform of a BBH in gas resembles that of a more massive BBH residing in vacuum. The effect is important for those GW sources in the band of space-borne detectors but negligible for those in ground-based ones. Furthermore, we carry out a matched-filtering search of the best fitting parameters. We find that the best-fit chirp mass could be significantly greater than the real mass when the gas effect is ignored. Our results have important implications for the future joint observation of BBHs using both ground- and space-based detectors.

scholarly journals Separating the intrinsic alignment signal and the lensing signal using self-calibration in photo-z surveys with KiDS450 and KV450 Data

2020 ◽  
Vol 495 (4) ◽  
pp. 3900-3919 ◽  
Author(s):  
Ji Yao ◽  
Eske M Pedersen ◽  
Mustapha Ishak ◽  
Pengjie Zhang ◽  
Anish Agashe ◽  
...  
Keyword(s):  
Full Potential ◽  
Photometric Redshift ◽  
Self Calibration ◽  
Intrinsic Shape ◽  
Best Fitting ◽  
Systematic Biases ◽  
Cosmic Shear ◽  
Validation Tests ◽  
The Impact ◽  
Best Fit

ABSTRACT To reach the full potential for the next generation of weak lensing surveys, it is necessary to mitigate the contamination of intrinsic alignments (IAs) of galaxies in the observed cosmic shear signal. The self-calibration (SC) of IAs provides an independent method to measure the IA signal from the survey data and the photometric redshift information. It operates differently from the marginalization method based on the IA modelling. In this work, we present the first application of SC to the KiDS450 data and the KV450 data, to split directly the intrinsic shape–galaxy density (Ig) correlation signal and the gravitational shear–galaxy density (Gg) correlation signal, using the information from photometric redshift (photo-z). We achieved a clear separation of the two signals and performed several validation tests. Our measured signals are found to be in general agreement with the KiDS450 cosmic shear best-fitting cosmology, for both lensing and IA measurements. For KV450, we use partial (high-z) data, and our lensing measurements are also in good agreement with KV450 cosmic shear best fit, while our IA signal suggests a larger IA amplitude for the high-z sample. We discussed the impact of photo-z quality on IA detection and several other potential systematic biases. Finally, we discuss the potential application of the information extracted for both the lensing signal and the IA signal in future surveys.

scholarly journals Stability analysis of three exoplanet systems

2020 ◽  
Vol 494 (2) ◽  
pp. 2280-2288
Author(s):  
J P Marshall ◽  
J Horner ◽  
R A Wittenmyer ◽  
J T Clark ◽  
M W Mengel
Keyword(s):  
Time Scales ◽  
Planetary Systems ◽  
Orbital Parameters ◽  
Exoplanetary Systems ◽  
Best Fitting ◽  
The Stability ◽  
Short Time ◽  
Exoplanet Systems ◽  
Best Fit

ABSTRACT The orbital solutions of published multiplanet systems are not necessarily dynamically stable on time-scales comparable to the lifetime of the system as a whole. For this reason, dynamical tests of the architectures of proposed exoplanetary systems are a critical tool to probe the stability and feasibility of the candidate planetary systems, with the potential to point the way towards refined orbital parameters of those planets. Such studies can even help in the identification of additional companions in such systems. Here, we examine the dynamical stability of three planetary systems, orbiting HD 67087, HD 110014, and HD 133131A. We use the published radial velocity measurements of the target stars to determine the best-fitting orbital solutions for these planetary systems using the systemic console. We then employ the N-body integrator mercury to test the stability of a range of orbital solutions lying within 3σ of the nominal best fit for a duration of 100 Myr. From the results of the N-body integrations, we infer the best-fitting orbital parameters using the Bayesian package astroemperor. We find that both HD 110014 and HD 133131A have long-term stable architectures that lie within the 1σ uncertainties of the nominal best fit to their previously determined orbital solutions. However, the HD 67087 system exhibits a strong tendency towards instability on short time-scales. We compare these results to the predictions made from consideration of the angular momentum deficit criterion, and find that its predictions are consistent with our findings.

Prediction of dry matter accumulation in bitter vetch

2017 ◽  
Author(s):  
Ufuk Karadavut ◽  
Adil Bakoglu ◽  
Halit Tutar ◽  
Kagan Kokten ◽  
Hava Seyma Yilmaz
Keyword(s):  
Growth Models ◽  
Block Design ◽  
Coefficient Of Determination ◽  
Dry Matter Accumulation ◽  
Randomized Block Design ◽  
Bitter Vetch ◽  
Best Fitting ◽  
Local Genotypes ◽  
Best Fit ◽  
Different Sources

This study was carried out in Bingol province on eastern Anatolian Region between 2013 and 2015. In this study, we obtained 14 bitter vetch genotypes from different sources. The experiment was carried our in three replications in randomized block design. Each plant was weekly measured for 6 weeks starting from germination. For each plant, plant height, fresh and dry stem weight, fresh and dry leaf weights were determined. Logistic, Richards and Weibull growth models were fitted to describe the growth pattern of the genotypes. The best fitting model criteria used were coefficient of determination and mean squared. Richards’s growth model was found to best fit the data for most of the genotypes. Logistic model was the worst fit. In Turkey, climate and soil properties have very large variations. For this, local genotypes showed large variation according to plating areas. YEREL LICE genotype showed more stable and it is the height identified all growth models than other local genotypes. However, IFVE 2923 SEL and IFVE 2977 SEL 2802 these genotypes gave positive results in different environmental conditions.

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