Panel Discussion--Factors related to perceiving the relative speed of leading vehicles in high-speed rear-end crashes

2012 ◽  
Author(s):  
Michael E. Maddox ◽  
Greg Fitch ◽  
Aaron Kiefer ◽  
Rudolf Mortimer ◽  
Jeffrey Muttart
Keyword(s):  
High Speed ◽  
Panel Discussion ◽  
Relative Speed

Panel Discussion – Factors related to perceiving the relative speed of leading vehicles in high-speed rear-end crashes

2012 ◽  
Vol 56 (1) ◽  
pp. 690-694
Author(s):  
Michael E. Maddox ◽  
Greg Fitch ◽  
Aaron Kiefer ◽  
Rudolf Mortimer ◽  
Jeffrey Muttart
Keyword(s):  
High Speed ◽  
Panel Discussion ◽  
Relative Speed

scholarly journals Controllers to Chase a High-Speed Evader Using a Pursuer with Variable Speed

2018 ◽  
Vol 8 (10) ◽  
pp. 1976 ◽  
Author(s):  
Jonghoek Kim
Keyword(s):  
Optical Flow ◽  
High Speed ◽  
Angular Rate ◽  
Relative Distance ◽  
Line Of Sight ◽  
Terminal Phase ◽  
Relative Speed ◽  
Variable Speed

This paper proposes a chasing controller to enable a pursuer to chase a high-speed evader such that the relative distance between the evader and the pursuer monotonically decreases as time passes. Our controller is designed to assure that the angular rate of Line-of-Sight joining the pair (the pursuer and the evader) is exactly zero at all time indexes. Assuming that the pursuee can readily observe optical flow, but only poorly detect looming, this pursuer’s movement is hardly detected by the pursuee. Consider the terminal phase when the pursuer is sufficiently close to the evader. As we slow down the relative speed of the pursuer with respect to the evader, we can reduce the probability of missing the high-speed evader. Thus, our strategy is to make the pursuer decrease its speed in the terminal phase, while ensuring that the distance between the evader and the pursuer monotonically decreases as time passes. The performance of our controller is verified utilizing MATLAB simulations.

Structure Dynamic Modification and Optimization for High-Speed Face Milling Cutter

2004 ◽  
Vol 471-472 ◽  
pp. 663-667 ◽  
Author(s):  
Wei Xiao Tang ◽  
Xing Ai ◽  
H.Y. Wu ◽  
Song Zhang ◽  
H. Jiang
Keyword(s):  
High Speed ◽  
Milling Process ◽  
Face Milling ◽  
Relative Speed ◽  
Structural Dynamic ◽  
High Speed Milling ◽  
Structural Dynamic Modification ◽  
The Face ◽  
Dynamic Modification ◽  
The Stability

Due to the complexity of high-speed milling process by high relative speed and interrupted cutting, the face milling cutters possess the multi-order modes and the vibrating displacements of the cutting edges under each modes affect adversely both the surface roughness and the life of machine/tool system worse than other structures. In order to improve the stability of milling process, this work focuses on the influence of the variables such as structure geometries and constraint conditions on the eigenfrequencies and modeshapes of cutter. As an example, the dynamic characteristics of several face cutters are analyzed and optimized by structural dynamic modification (SDM) techniques.

scholarly journals Collision of Two Highly Ionized Clouds of Gas

1958 ◽  
Vol 8 ◽  
pp. 1069-1072
Author(s):  
F. D. Kahn
Keyword(s):  
Energy Density ◽  
High Speed ◽  
Present Note ◽  
Magnetic Energy ◽  
Kinetic Energy Density ◽  
Relative Speed ◽  
Magnetic Energy Density ◽  
Collective Interaction ◽  
Collective Plasma ◽  
Individual Particles

If two rarefied masses of gas collide at a sufficiently high speed, their relative motion will be stopped by a collective plasma instability, rather than by collisions of individual particles. This is true even if the gases are initially non-ionized. In the present note, the possible influence of magnetic fields is ignored for the most part, but a criterion is found to decide under what conditions the collective interaction remains dominant even when they cannot be ignored. It seems that the neglect of magnetic effects may be justified, for example, in the case of two galaxies in collision at a relative speed of 1000 km/sec. The magnetic energy density here is (1/8π)H2∼4X10−12 erg/cm3 (with H∼10−5 gauss), which is much less than the kinetic energy density 1/2NmU2∼8X10−9 erg/cm3 (with N∼1 particle per cm3).

scholarly journals Speed and direction of an obstacle using virtual window

2019 ◽  
Vol 13 (1) ◽  
pp. 109
Author(s):  
Mohd Asri Mansor
Keyword(s):  
High Speed ◽  
Relative Speed ◽  
Virtual Window ◽  
Very High ◽  
Moving Obstacle

A virtual window is used to determine the direction and speed of a uniformly moving obstacle. Two intersections with the virtual window at different location are used to calculate the relative path and speed of the obstacle. Two simulations were performed using Excel 2010. The first simulation simulates a practical running of a uniformly moving obstacle, while the second has the obstacle moving at a very high speed. The result shows that the system was able to determine the relative speed and path of the uniformly moving obstacle accurately.

Introduction

2018 ◽  
pp. 1-16
Keyword(s):  
Power Loss ◽  
High Speed ◽  
Estimation Problem ◽  
Airborne Radar ◽  
Relative Speed ◽  
Dynamic Power ◽  
Ambiguity Estimation ◽  
Range Migration

Although the airborne radar introduced many advantages over other radars, such as ground radars, in detecting high speed air targets, it suffers from many problems. These problems can be concluded as, first, the range migration problem that happens due to the high relative speed between the airborne radar and the high speed air targets and the Doppler ambiguity estimation problem; second, the limited input dynamic power range of the radar receiver and the power loss due to targets range; third, the effects of jamming and clutter which are more effective than ground radars; and finally, the airborne system is a perfect target for enemy threats such as jamming and spoofing.

scholarly journals Relationships Between Physical Testing and Match Activity Profiles Across the Australian Football League Participation Pathway

2019 ◽  
Vol 14 (6) ◽  
pp. 771-778
Author(s):  
Jade A.Z. Haycraft ◽  
Stephanie Kovalchik ◽  
David B. Pyne ◽  
Sam Robertson
Keyword(s):  
Physical Fitness ◽  
High Speed ◽  
Vertical Jump ◽  
National Level ◽  
Maximal Velocity ◽  
Relative Speed ◽  
Australian Football League ◽  
Jump Test ◽  
Physical Testing ◽  
Australian Football

Purpose: To establish levels of association between physical fitness and match activity profiles of players in the Australian Football League (AFL) participation pathway. Methods: Players (N = 287, range 10.9–19.1 y) were assessed on 20-m sprint, AFL agility, vertical jump and running vertical jump, 20-m multistage fitness test (MSFT), and Athletic Abilities Assessment. Match activity profiles were obtained from global positioning system measures: relative speed, maximal velocity, and relative high-speed running. Results: Correlational analyses revealed moderate relationships between sprint (r = .32–.57, P ≤ .05) and jump test scores (r = .34–.78, P ≤ .05) and match activity profiles in Local U12, Local U14, National U16, and National U18s, except jump tests in National U18s. AFL agility was also moderate to strongly associated in Local U12, Local U14, Local U18, and National U16s (r = .37–.87, P ≤ .05) and strongly associated with relative speed in Local U18s (r = .84, P ≤ .05). Match relative speed and high-speed running were moderate to strongly associated with 20-m MSFT in Local U14, Local U18, and National U18s (r = .41–.95, P ≤ .05) and Athletic Abilities Assessment in Local U12 and Local U18s (r = .35–.67, P ≤ .05). Match activity profile demands increased between Local U12 and National U16s, then plateaued. Conclusions: Physical fitness relates more strongly to match activity profiles in younger adolescent and national-level players. Recruiters should consider adolescent physical fitness and match activity profiles as dynamic across the AFL participation pathway.

EXPERIMENTAL STUDY OF HYDRODYNAMIC IMPACT PRESSURES ON HIGH SPEED PLANING CRAFT

2016 ◽  
Vol 158 (B1) ◽  
Author(s):  
E Begovic ◽  
C Bertorello ◽  
A Bove ◽  
S De Rosa ◽  
E Fasano ◽  
...  
Keyword(s):  
Experimental Study ◽  
High Speed ◽  
Dynamic Behaviour ◽  
Pressure Field ◽  
Elastic Behaviour ◽  
Relative Speed ◽  
Structural Dynamic ◽  
Hydrodynamic Impact ◽  
Planing Craft ◽  
Rough Sea

This paper presents an experimental research for the assessment of pressure field on the bottom of a mono-hedral hard chine hull at high relative speed. Tests have been performed in rough sea for two wave lengths at Fn ranging from 0.79 to 1.46. The measured pressures have been analysed in time and in frequency domain. The pressure distribution along a rectangular panel of the hull bottom has been identified. The comparison of measured values and those ones provided by Classification Societies has been performed and pressure results have been used to investigate the interactions between the fluid and the craft structure. The elastic behaviour of different bottom panels is analysed, and the scantling of a typical bottom panel, made from four materials, have been calculated, in order to investigate the structural dynamic behaviour.

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