scholarly journals From the the center of pressure to the center of gravity, a new algorithm for a step forward in stabilometry

2015 ◽  
Vol 13 ◽  
pp. 264 ◽  
Author(s):  
Bernard Gagey ◽  
Olivier Bourdeaux ◽  
Pierre-Marie Gagey
Keyword(s):  
Differential Equation ◽  
Boundary Conditions ◽  
Edge Effects ◽  
Center Of Pressure ◽  
International Committee ◽  
Center Of Gravity ◽  
The Other ◽  
New Method

Introduction: For more than thirty years, in clinical stabilometry, we have been using the center of pressure (CoP) to calculate stabilometric parameters. That was a mistake because the CoP signal comprises two series of information, one on the position of the center of gravity (CoG), and the other on the acceleration of the CoG. Objective: A step forward must be taken in order to separate these variables clearly using the CoG instead of the CoP to calculate stabilometric parameters. A lot of methods have been proposed to obtain the CoG from the CoP, yet none of them is used. We present a new algorithm for the same purpose. Method: A new mathematical way for solving the differential equation of DA Winter is proposed, which can use the "edge effects" due to known boundary conditions of the variables. Result: Solving the Winter's equation has two interests: Clinicians may think about what is observed through a model, and inter-subjects comparisons are better thanks to Winter's coefficient. Conclusion: During its next session, the international Committee for standardization of clinical stabilometry must choose one method to obtain the CoG from the CoP, before this choice is made, this new method must be known, well known and well understood because it could be the best choice.

Akbari-Ganji's Method

2017 ◽  
pp. 246-273
Keyword(s):  
Differential Equation ◽  
Partial Differential Equation ◽  
Differential Equations ◽  
Boundary Conditions ◽  
Chemical Engineering ◽  
Solid Mechanics ◽  
Nonlinear Partial Differential Equation ◽  
The Other ◽  
Partial Differential ◽  
New Approach

The nonlinear partial differential equation governing on the mentioned system has been investigated by a simple and innovative method which we have named it Akbari-Ganji's Method or AGM. It is notable that this method has been compounded by Laplace transform theorem in order to covert the partial differential equation governing on the afore-mentioned system to an ODE and then the yielded equation has been solved conveniently by this new approach (AGM). One of the most important reasons of selecting the mentioned method for solving differential equations in a wide variety of fields not only in heat transfer science but also in different fields of study such as solid mechanics, fluid mechanics, chemical engineering, etc. in comparison with the other methods is as follows: Obviously, according to the order of differential equations, we need boundary conditions so in the case of the number of boundary conditions is less than the order of the differential equation, this method can create additional new boundary conditions in regard to the own differential equation and its derivatives. Therefore, a solution with high precision will be acquired. With regard to the afore-mentioned explanations, the process of solving nonlinear equation(s) will be very easy and convenient in comparison with the other methods.

A Comparison of the Bethesda and New Oxford Methods of Factor VIII Antibody Assay

1982 ◽  
Vol 47 (01) ◽  
pp. 072-075 ◽  
Author(s):  
D E G Austen ◽  
K Lechner ◽  
C R Rizza ◽  
I L Rhymes
Keyword(s):  
Factor Viii ◽  
Excellent Agreement ◽  
International Committee ◽  
The Other ◽  
Antibody Assay ◽  
Collaborative Trial

SummaryA collaborative trial has been carried out under the auspices of the International Committee on Thrombosis and Haemostasis to compare the Bethesda and New Oxford methods of antibody assay. It was found that errors between laboratories were much greater than those within laboratories and each laboratory had a bias whereby it always rated samples high or low with respect to the other laboratories. However there was excellent agreement in the order in which laboratories ranked antibody samples and if a standard antibody sample could be provided there would be a significant improvement in numerical agreement between laboratories. On average, for this exercise, a result for a given sample in Bethesda units was 1.21 times the result in New Oxford units although it must be stressed that this ratio could vary from sample to sample.

scholarly journals Baropodometric technology used to analyze types of weight-bearing during hemiparetic upright position

2012 ◽  
Vol 25 (3) ◽  
pp. 583-594 ◽  
Author(s):  
Lidiane Teles de Menezes ◽  
Paulo Henrique Ferreira de Araujo Barbosa ◽  
Abraão Souza Costa ◽  
Anderson Castro Mundim ◽  
Gabrielly Craveiro Ramos ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Center Of Pressure ◽  
Weight Bearing ◽  
Upright Position ◽  
The Other ◽  
Control Group ◽  
Gender And Age ◽  
Coordination System ◽  
Support Area ◽  
Arch Index

INTRODUCTION: Although baropodometric analysis has been published since the 1990s, only now it is found a considerable number of studies showing different uses in the rehabilitation. OBJECTIVE: To amplify the use of this technology, this research aimed to analyze baropodometric records during upright position of subjects with hemiparesis, describing a way to define weight-bearing profiles in this population. METHOD: 20 healthy subjects were matched by gender and age with 12 subjects with chronic spastic hemiparesis. This control group was formed to establish the limits of symmetry during weight-bearing distribution in the hemiparesis group. Next, hemiparesis group was submitted to procedures to measure baropodometric records used to provide variables related to the weight-bearing distribution, the arch index and the displacements in the center of pressure (CoP). Data were used to compare differences among kinds of weight-bearing distribution (symmetric, asymmetric toward non-paretic or paretic foot) and coordination system for CoP displacements. RESULTS: Hemiparesis group was compounded by eight symmetrics, eight asymmetrics toward non-paretic foot and four asymmetric toward paretic foot. Significant differences in the weight-bearing distributions between non-predominantly and predominantly used foot did not promote differences in the other baropodometric records (peak and mean of pressure, and support area). Mainly in the asymmetry toward non-paretic foot it was observed significant modifications of the baropodometric records. CONCLUSION: Baropodometric technology can be used to analyze weight-bearing distribution during upright position of subjects with hemiparesis, detecting different kinds of weight-bearing profiles useful to therapeutic programs and researches involving subjects with this disability.

Large Time Behavior of Solutions to One Nonlinear Integro-Differential Equation

2008 ◽  
Vol 15 (3) ◽  
pp. 531-539
Author(s):  
Temur Jangveladze ◽  
Zurab Kiguradze
Keyword(s):  
Magnetic Field ◽  
Differential Equation ◽  
Boundary Conditions ◽  
Large Time ◽  
Dirichlet Boundary ◽  
Large Time Behavior ◽  
Dirichlet Boundary Conditions ◽  
Time Behavior ◽  
Integro Differential Equation ◽  
Homogeneous Data

Abstract Large time behavior of solutions to the nonlinear integro-differential equation associated with the penetration of a magnetic field into a substance is studied. The rate of convergence is given, too. Dirichlet boundary conditions with homogeneous data are considered.

scholarly journals On Newcomb's method of investigating periodicities and its application to Brückner's weather cycle

1914 ◽  
Vol 90 (619) ◽  
pp. 349-355
Keyword(s):  
Thermal Radiation ◽  
The Other ◽  
New Method ◽  
Critical Examination ◽  
Numerical Work ◽  
Average Value ◽  
Other Hand ◽  
Relationship Of ◽  
The Relationship ◽  
Great Simplicity

During the last few years of his life Prof. Simon Newcomb was keenly interested in the problem of periodicities, and devised a new method for their investigation. This method is explained, and to some extent applied, in a paper entitled "A Search for Fluctuations in the Sun's Thermal Radiation through their Influence on Terrestrial Temperature." The importance of the question justifies a critical examination of the relationship of the older methods to that of Newcomb, and though I do not agree with his contention that his process gives us more than can be obtained from Fourier's analysis, it has the advantage of great simplicity in its numerical work, and should prove useful in a certain, though I am afraid, very limited field. Let f ( t ) represent a function of a variable which we may take to be the time, and let the average value of the function be zero. Newcomb examines the sum of the series f ( t 1 ) f ( t 1 + τ) + f ( t 2 ) f ( t 2 + τ) + f ( t 3 ) f ( t 3 + τ) + ..., where t 1 , t 2 , etc., are definite values of the variable which are taken to lie at equal distances from each other. If the function be periodic so as to repeat itself after an interval τ, the products are all squares and each term is positive. If, on the other hand, the periodic time be 2τ, each product will be negative and the sum itself therefore negative. It is easy to see that if τ be varied continuously the sum of the series passes through maxima and minima, and the maxima will indicated the periodic time, or any of its multiples.

Generalized plane stress in a semi-infinite strip under arbitrary end-load

1964 ◽  
Vol 281 (1385) ◽  
pp. 184-206 ◽  
Keyword(s):  
Differential Equation ◽  
Ordinary Differential Equation ◽  
Boundary Conditions ◽  
Fourth Order ◽  
Plane Stress ◽  
Stress Function ◽  
Infinite Strip ◽  
Order Ordinary Differential Equation ◽  
Orthogonal Functions

The problem involves the determination of a biharmonic generalized plane-stress function satisfying certain boundary conditions. We expand the stress function in a series of non-orthogonal eigenfunctions. Each of these is expanded in a series of orthogonal functions which satisfy a certain fourth-order ordinary differential equation and the boundary conditions implied by the fact that the sides are stress-free. By this method the coefficients involved in the biharmonic stress function corresponding to any arbitrary combination of stress on the end can be obtained directly from two numerical matrices published here The method is illustrated by four examples which cast light on the application of St Venant’s principle to the strip. In a further paper by one of the authors, the method will be applied to the problem of the finite rectangle.

Locomotory Diseases Influence on Body Equilibrium and Balance

2014 ◽  
Vol 555 ◽  
pp. 652-658 ◽  
Author(s):  
Barbu Cristian Braun ◽  
Ileana Constanta Rosca
Keyword(s):  
Body Mass ◽  
Human Subjects ◽  
Force Plate ◽  
The Body ◽  
The Other ◽  
New Method ◽  
First Person ◽  
Mass Center ◽  
Stability Problems ◽  
Research Stage

The paper describes a new method of body equilibrium evaluation applied for different human subjects, the principal aim being to demonstrate to what extent any locomotory diseases could influence the body stability and equilibrium. The research refers to identify some persons with different locomotory diseases and to find both the influence on equilibrium and stability and if possible to improve them. Our research stage, synthesized in this paper, explains the body equilibrium evaluation in orthostatic posture done for different subjects, aged between 20 and 40 years. A number of 10 relevant persons were considered to be evaluated, 2 of them having some locomotory diseases. The first person presents any neuro-motor stability problems in case of long standing case. The other person has both Achilles tendons torn and operated. All subjects were tested in orthostatic posture, in 3 distinct positions, using a Kistler force plate. The experiments referred to the body mass center (COM) displacement in sagittal and lateral planes, representing an interesting characteristic for its equilibrium. It was shown that the person with diseases affecting stability presented a loss of equilibrium when standing for 10-20 seconds, i.e. higher COM displacements in both planes reported to the other tested subjects.

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