scholarly journals The Mass Centre in Relativity

Nature ◽  
1940 ◽  
Vol 145 (3676) ◽  
pp. 587-587 ◽  
Author(s):  
MAX BORN ◽  
KLAUS FUCHS
Keyword(s):  
Mass Centre

scholarly journals An automated driver based on convergent vector fields

2002 ◽  
Vol 216 (4) ◽  
pp. 329-347 ◽  
Author(s):  
T J Gordon ◽  
M C Best ◽  
P J Dixon
Keyword(s):  
Vector Field ◽  
Feedback Control ◽  
Field Analysis ◽  
Driver Model ◽  
Cruise Control ◽  
Essential Information ◽  
Mass Centre ◽  
Reference Path ◽  
Driving Task ◽  
Specific Implementation

This paper describes a new general framework for the action of an automated driver (or driver model) to provide the control of longitudinal and lateral dynamics of a road vehicle. The context of the problem is assumed to be in high-speed competitive driving, as in motor racing, where the requirement is for maximum possible speed along a track, making use of a reference path (racing line) but with the capacity for obstacle avoidance and recovery from large excursions. While not necessarily representative of a human driver, the analysis provides worthwhile insight into the nature of the driving task and offers a new approach for vehicle lateral and longitudinal control; it also has applications in less demanding applications such as Advanced Cruise Control systems. As is common in the literature, the driving task is broken down into two distinct subtasks: path planning and local feedback control. In the first of these tasks, an essentially geometric approach is taken here, which makes use of a vector field analysis. At each location x the automated driver is to prescribe a vector w for the desired vehicle mass centre velocity; the spatial distribution and global properties of w( x) provide essential information for stability analysis, as well as control reference. The resulting vector field is considered in the context of limited friction and limited mass centre accelerations, leading to constraints on ∇ w. Provided such constraints are satisfied, and using suitable adaptation of w( x) when required, it is shown that feedback control can be applied to guarantee stable asymptotic tracking of a reference path, even under limit handling conditions. A specific implementation of the method is included, using dual non-linear SISO (single-input single-output) controllers.

scholarly journals “Mass Centre” Vectorization Algorithm for Vehicle’s Counting Portable Video System

2016 ◽  
Vol 17 (4) ◽  
pp. 289-297
Author(s):  
Vladislav Gaidash ◽  
Alexander Grakovski
Keyword(s):  
Low Cost ◽  
Transport Infrastructure ◽  
Transport Systems ◽  
Intelligent Transport Systems ◽  
Basic Algorithm ◽  
Counting System ◽  
Object A ◽  
Intelligent Transport ◽  
Mass Centre ◽  
Mobile Vehicle

Abstract Vehicle counting is one of the most basic challenges during the development and establishment of Intelligent Transport Systems (ITS). The main reason for vehicle counting is the necessity of monitoring and maintaining the transport infrastructure, preventing different kind of faults such as traffic jams. The main applied solution to this problem is video surveillance, which is presented by different kind of systems. Some of these systems use a network of static traffic cameras, expensive for establish and maintain, or mobile units, fast for redeployment, but fewer in diversity. In this paper, one particular concept of a low-cost mobile vehicle counting system is investigated, which uses an object detection method based on calculating “mass centre” of detected features of possible object. A hypothesis of improvement of the basic algorithm was formulated and a modification was proposed. In order to prove the hypothesis, both basic and modified algorithms were tested and evaluated.

scholarly journals A Three-Dimensional Skeletal Reconstruction of the Stem Amniote Orobates pabsti (Diadectidae): Analyses of Body Mass, Centre of Mass Position, and Joint Mobility

PLoS ONE ◽  
2015 ◽  
Vol 10 (9) ◽  
pp. e0137284 ◽  
Author(s):  
John A. Nyakatura ◽  
Vivian R. Allen ◽  
Jonas Lauströer ◽  
Amir Andikfar ◽  
Marek Danczak ◽  
...  
Keyword(s):  
Body Mass ◽  
Three Dimensional ◽  
Joint Mobility ◽  
Centre Of Mass ◽  
Mass Centre ◽  
Mass Position ◽  
Skeletal Reconstruction

An Analysis of the Motion of a Centrifugal Impeller in Overspeed Test

2008 ◽  
Author(s):  
Richard J. Gozdawa ◽  
Alfred W. Crook
Keyword(s):  
Angular Velocity ◽  
Centrifugal Impeller ◽  
Centrifugal Compressors ◽  
Moments Of Inertia ◽  
Mass Centre

This paper arose from the experience in overspeeding the impellers of centrifugal compressors. The industry had information that the ratio of certain moments of inertia of the impeller (about axis to about a diameter through the mass centre) should be outside a range from 0.7 to 1.5, but the basis for this prohibition was unknown. The tests provided confirmation of it in that impellers were spun successfully to overspeed. The observation was consistent with a conical precession of the impeller at an angular velocity, which was a small fraction of the angular velocity of the drive. The purpose of the investigation was to search for the dynamical basis of the prohibition.

scholarly journals The rotary component of leg force during walking and running

2019 ◽  
Vol 16 (154) ◽  
pp. 20190105 ◽  
Author(s):  
Manish Anand ◽  
Justin Seipel
Keyword(s):  
Sagittal Plane ◽  
Human Subjects ◽  
Reaction Force ◽  
Average Power ◽  
Power Input ◽  
Human Locomotion ◽  
Strong Positive Correlation ◽  
Mass Centre ◽  
Force Magnitude ◽  
Locomotion Speed

The component of ground reaction force (GRF) acting perpendicular to the leg in the sagittal plane during human locomotion (acting in a rotary direction) has not been systematically investigated and is not well understood. In this paper, we investigate this rotary component of the GRF of 11 human subjects (mean age ± s.d.: 26.6 ± 2.9 years) while walking and speed walking on a treadmill, along with eight human subjects (mean age ± s.d.: 26.3 ± 3.1) running on a treadmill. The GRF on both legs was measured, along with estimates of the subject's mass centre and the centre of pressure of each foot to yield total leg lengths and leg angle. Across all steady walking and running speeds, we find that the rotary component of the GRF has significant magnitude (peak values from 5% to 38% of body weight, from slow walking to moderate running, respectively) and implies leg propulsion of the mass centre in the rotary direction. Furthermore, peak rotary force magnitude over stance increases with locomotion speed for both walking and running ( p < 0.05), and the time-averaged (mean) rotary force shows a slight increase with walking speed (though the mean force trend is uncertain for running). Also, an estimate of average power input from the rotary force of the leg acting at the mass centre shows moderate and strong positive correlation with locomotion speed for running and walking respectively ( p < 0.05). This study also shows that the rotary force acts differently in walking versus running: rotary force is predominantly positive during running, but during walking it exhibits both positive and negative phases with net positive force found over the whole stride.

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