Critique of successive differencing method of regression analysis

1968 ◽  
Vol 46 (10) ◽  
pp. S1061-S1063
Author(s):  
Mario Iona ◽  
Michael Wiskerchen
Keyword(s):  
Time Dependence ◽  
Linear Time ◽  
Cosmic Ray ◽  
Maximum Effect ◽  
Regression Techniques ◽  
Nucleonic Component ◽  
Slope Error ◽  
The Difference ◽  
Mathematical Foundations ◽  
Simulated Time

Various regression techniques have been proposed to calculate barometric coefficients from time-varying cosmic rays recorded by neutron monitors. One of these, the successive differencing method, was carefully examined by applying the technique to simulated time-dependent and time-independent cosmic-ray data and also by investigating the mathematical foundations of the technique. When applying the successive differencing method to time-independent data, the slope and slope error values were found to be dependent on the order in which the data appeared. By ordering the data from highest to lowest pressure, the slope error increased markedly. This falsification of the slope can be shown to be due to improper weighting of the differenced data. Calculations have also been performed to show that the successive differencing method, when applied to intensities containing a linear time dependence, produces a regression slope which retains a time dependence proportional to the difference between the first and last pressure values. The falsification of the slope due to improper weighting of the differenced data can be very much larger than the maximum effect of any reasonable time variation of the nucleonic component.

scholarly journals Concentration of Banking Sector and Loan Markups in Short Term: An Example from Poland

2014 ◽  
Vol 5 (2) ◽  
pp. 26-44
Author(s):  
Krysztof Drachal
Keyword(s):  
Monetary Policy ◽  
Banking Sector ◽  
Mortgage Market ◽  
Future Research ◽  
Simple Linear Regression ◽  
Short Term ◽  
Monthly Data ◽  
Regression Techniques ◽  
The Difference ◽  
The Relationship

The aim of this paper is to present an analysis of the relationship between concentration of the banking sector and banks' markups on offered loans. The markup is understood as the difference between the rate offered by banks and the reference rate fixed by the Monetary Policy Council. The period between 2009 and 2013 was analyzed. Monthly data from the Polish banking sector were considered. This paper also consists of the literature review, which focuses on the mortgage market. The methodology used for the analysis is based mainly on simple linear regression techniques. It is found that such methods are not sufficient to give conclusive answers. Therefore additional future research is proposed.

Spectral yield estimation of NTS explosions

1991 ◽  
Vol 81 (4) ◽  
pp. 1292-1308
Author(s):  
Steven R. Taylor ◽  
Farid U. Dowla
Keyword(s):  
Shock Wave ◽  
Template Matching ◽  
Spectral Shape ◽  
Source Material ◽  
Matching Function ◽  
Spectral Matching ◽  
Matching Technique ◽  
Regression Techniques ◽  
The Difference ◽  
Unknown Event

Abstract The yields of 299 NTS explosions have been estimated from Pn, Pg and Lg spectra (between 0.1 and 10 Hz) at four regional seismic stations. A spectral template matching technique is used where the spectra from an explosion of unknown yield are compared with the spectra of explosions of known yield. A matching function is defined that is a scaled inverse of the difference between the spectra from the known and unknown explosions. The yields from the seven closest matching explosions are then averaged to estimate the yield of the unknown event. The spectral matching technique appears to perform as well as standard regression techniques utilizing mb(Pn) and mb(Lg) measurements except that no geologic information (such as gas-filled porosity) is required. However, the spectral matching technique is only applicable to very well-calibrated test sites. The key to spectral matching is that the spectral shape is sensitive to the near-source geology. In addition to affecting the absolute spectral levels (i.e., coupling), the dynamic response of the near source material to the radiated shock wave is a major factor controlling the shape of the radiated spectra. The spectral shape can therefore be used as an indicator for predicting the coupling of an explosion, which can be subsequently used to predict its yield.

Techniques to Predict Agricultural Droughts

2005 ◽  
Author(s):  
Zekai Şen
Keyword(s):  
Crop Yield ◽  
Satellite Data ◽  
Wheat Yield ◽  
Weather Variables ◽  
Short Term ◽  
Yield Model ◽  
Regression Techniques ◽  
The Difference ◽  
Effects Of Drought

In general, the techniques to predict drought include statistical regression, time series, stochastic (or probabilistic), and, lately, pattern recognition techniques. All of these techniques require that a quantitative variable be identified to define drought, with which to begin the process of prediction. In the case of agricultural drought, such a variable can be the yield (production per unit area) of the major crop in a region (Kumar, 1998; Boken, 2000). The crop yield in a year can be compared with its long-term average, and drought intensity can be classified as nil, mild, moderate, severe, or disastrous, based on the difference between the current yield and the average yield. Regression techniques estimate crop yields using yield-affecting variables. A comprehensive list of possible variables that affect yield is provided in chapter 1. Usually, the weather variables routinely available for a historical period that significantly affect the yield are included in a regression analysis. Regression techniques using weather data during a growing season produce short-term estimates (e.g., Sakamoto, 1978; Idso et al., 1979; Slabbers and Dunin, 1981; Diaz et al., 1983; Cordery and Graham, 1989; Walker, 1989; Toure et al., 1995; Kumar, 1998). Various researchers in different parts of the world (see other chapters) have developed drought indices that can also be included along with the weather variables to estimate crop yield. For example, Boken and Shaykewich (2002) modifed the Western Canada Wheat Yield Model (Walker, 1989) drought index using daily temperature and precipitation data and advanced very high resolution radiometer (AVHRR) satellite data. The modified model improved the predictive power of the wheat yield model significantly. Some satellite data-based variables that can be used to predict crop yield are described in chapters 5, 6, 9, 13, 19, and 28. The short-term estimates are available just before or around harvest time. But many times long-term estimates are required to predict drought for next year, so that long-term planning for dealing with the effects of drought can be initiated in time.

scholarly journals On the König deficiency of zero-reducible graphs

2019 ◽  
Vol 39 (1) ◽  
pp. 273-292
Author(s):  
Miklós Bartha ◽  
Miklós Krész
Keyword(s):  
Perfect Matching ◽  
Linear Time ◽  
Perfect Matchings ◽  
Covering Number ◽  
Matching Number ◽  
Empty Graph ◽  
Reduction System ◽  
Vertex Covering ◽  
Np Complete ◽  
The Difference

Abstract A confluent and terminating reduction system is introduced for graphs, which preserves the number of their perfect matchings. A union-find algorithm is presented to carry out reduction in almost linear time. The König property is investigated in the context of reduction by introducing the König deficiency of a graph G as the difference between the vertex covering number and the matching number of G. It is shown that the problem of finding the König deficiency of a graph is NP-complete even if we know that the graph reduces to the empty graph. Finally, the König deficiency of graphs G having a vertex v such that $$G-v$$G-v has a unique perfect matching is studied in connection with reduction.

scholarly journals Time dependence of the helium flux measured by PAMELA

2019 ◽  
Vol 209 ◽  
pp. 01004
Author(s):  
N. Marcelli ◽  
O. Adriani ◽  
G. C. Barbarino ◽  
G. A. Bazilevskaya ◽  
R. Bellotti ◽  
...  
Keyword(s):  
Energy Range ◽  
Time Dependence ◽  
Cosmic Radiation ◽  
Cosmic Ray ◽  
Space Experiment ◽  
Precision Measurements ◽  
Solar Modulation ◽  
Monthly Basis ◽  
The Galaxy ◽  
Crucial Information

Precision measurements of the Z = 2 component in cosmic radiation provide crucial information about the origin and propagation of the second most abundant cosmic ray species in the Galaxy (9% of the total). These measurements, acquired with the PAMELA space experiment orbiting Earth, allow to study solar modulation in details. Helium modulation is compared to the modulation of protons to study possible dependencies on charge and mass. The time dependence of helium fluxes on a monthly basis measured by PAMELA has been studied for the period between July 2006 to January 2016 in the energy range from 800 MeV/n to ~ 20 GeV/n.

Baryon production at LHC experiments: average pt of hyperons versus energy

2020 ◽  
Vol 35 (13) ◽  
pp. 2050067
Author(s):  
Olga I. Piskounova
Keyword(s):  
Cosmic Ray ◽  
String Model ◽  
Baryon Production ◽  
Proton Antiproton ◽  
Proton Proton ◽  
Low Energies ◽  
Momentum Spectra ◽  
Transverse Momentum Spectra ◽  
The Difference ◽  
Proton Proton Collisions

This paper examines the transverse momentum spectra of baryons in the multiparticle production at modern colliders in the frameworks of Quark–Gluon String Model (QGSM). It discusses: (i) the difference in [Formula: see text] hyperon spectra at proton–antiproton versus proton–proton reactions on previous colliders; (ii) the difference in hyperon spectra between the experiments on colliders of low energies and the results from modern machines; (iii) the growth of average transverse momenta of [Formula: see text] hyperon with the energies of proton–proton collisions up to [Formula: see text] TeV of LHC experiments. This analysis of baryon spectra led to the following conclusions. First, the fragmentation of antidiquark–diquark side of one-pomeron diagram makes the major contribution to baryon production spectra in the asymmetric [Formula: see text] reaction. Second, the average [Formula: see text]’s of hyperons in [Formula: see text] collisions steadily grow with energy in the range from [Formula: see text] GeV to 7 TeV. The additional conclusion is the following: since no dramatic changes have been seen in the characteristics of baryon production, the hadroproduction processes do not cause the “knee” in the cosmic ray proton spectra at the energies between Tevatron collider and LHC.

Stochastic Estimation of Human Ankle Mechanical Impedance in Lateral/Medial Rotation

2014 ◽  
Author(s):  
Evandro M. Ficanha ◽  
Mohammad Rastgaar
Keyword(s):  
Degrees Of Freedom ◽  
Muscle Activation ◽  
Transfer Functions ◽  
Linear Time ◽  
Mechanical Impedance ◽  
Linear Time Invariant ◽  
Ankle Impedance ◽  
Human Ankle ◽  
Medial Rotation ◽  
The Difference

This article compares stochastic estimates of human ankle mechanical impedance when ankle muscles were fully relaxed and co-contracting antagonistically. We employed Anklebot, a rehabilitation robot for the ankle to provide torque perturbations. Surface electromyography (EMG) was used to monitor muscle activation levels and these EMG signals were displayed to subjects who attempted to maintain them constant. Time histories of ankle torques and angles in the lateral/medial (LM) directions were recorded. The results also compared with the ankle impedance in inversion-eversion (IE) and dorsiflexion-plantarflexion (DP). Linear time-invariant transfer functions between the measured torques and angles were estimated for the Anklebot alone and when a human subject wore it; the difference between these functions provided an estimate of ankle mechanical impedance. High coherence was observed over a frequency range up to 30 Hz. The main effect of muscle activation was to increase the magnitude of ankle mechanical impedance in all degrees of freedom of ankle.

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