57,596 research outputs found
Apparatus for measuring an aircraft's speed and height
An apparatus for measuring aircraft horizontal speed and height above ground without the need for airborne cooperative devices is presented. Two ground level TV cameras separated by a measured distance and pointed at zenith are placed in line with the projection of the expected path of the aircraft. Speed is determined by measuring the time that it takes the aircraft to travel between the fields of view of the two TV cameras using zenith crossings as the reference points. Height is determined by correlating the speed with the time required to cross the field of view of either of the two cameras
A method for measuring aircraft height and velocity using dual television cameras
A unique electronic optical technique, consisting of two closed circuit television cameras and timing electronics, was devised to measure an aircraft's horizontal velocity and height above ground without the need for airborne cooperative devices. The system is intended to be used where the aircraft has a predictable flight path and a height of less than 660 meters (2,000 feet) at or near the end of an air terminal runway, but is suitable for greater aircraft altitudes whenever the aircraft remains visible. Two television cameras, pointed at zenith, are placed in line with the expected path of travel of the aircraft. Velocity is determined by measuring the time it takes the aircraft to travel the measured distance between cameras. Height is determined by correlating this speed with the time required to cross the field of view of either camera. Preliminary tests with a breadboard version of the system and a small model aircraft indicate the technique is feasible
Skeletal stressing method and apparatus Patent
Method and apparatus for applying compressional forces to skeletal structure of subject to simulate force during ambulatory condition
Programmable physiological infusion
A programmable physiological infusion device and method are provided wherein a program source, such as a paper tape, is used to actuate an infusion pump in accordance with a desired program. The system is particularly applicable for dispensing calcium in a variety of waveforms
Weight simulator
Device applies compressive force to bone to minimize loss of bone calcium during weightlessness or bedrest. Force is applied through weights, or hydraulic, pneumatic or electrically actuated devices. Device is lightweight and easy to maintain and operate
Modelling Safety-Related Driving Behaviour - the Impact of Parameter Values
Traffic simulation models make assumptions about the safety-related behaviour of drivers. These
assumptions may or may not replicate the real behaviour of those drivers who adopt seemingly unsafe
behaviour, for example running red lights at signalised intersections or too closely following the vehicles
in front. Such behaviour results in the performance of the system that we observe but will often result in
conflicts and very occasionally in accidents. The question is whether these models should reflect safe behav-
iour or actual behaviour. Good design should seek to enhance safety, but is the safety of a design neces-
sarily enhanced by making unrealistically optimistic assumptions about the safety of drivers behaviour?
This paper explores the questions associated with the choice of values for safety-related parameters in
simulation models. The paper identifies the key parameters of traffic simulation models and notes that sev-
eral of them have been derived from theory or informed guesswork rather than observation of real behav-
iour and that, even where they are based on observations, these may have been conducted in circumstances
quite different to those which now apply. Tests with the micro-simulation model DRACULA demonstrate
the sensitivity of model predictions—and perhaps policy decisions—to the value of some of the key param-
eters. It is concluded that, in general, it is better to use values that are realistic-but-unsafe than values that
are safe-but-unrealistic. Although the use of realistic-but-unsafe parameter values could result in the adop-
tion of unsafe designs, this problem can be overcome by paying attention to the safety aspects of designs.
The possibility of using traffic simulation models to culties involved in doing so are discussed
Programmed physiological infusion system
Infusion system delivers incremental volumes from a reservoir with a piston pump at a rate that varies in time and follows the envelope of a preprogrammed curve
Selected aspects of lunar mare geology from Apollo orbital photography
Crater size-frequency distributions were studied (100-500 m) and are shown to provide significant integrated information concerning mare surface ages, subsurface stratigraphy, and surficial geology. Equilibrium cratering is discussed gradually reducing the relative numbers of craters smaller than 300-400 m in diameter as surfaces age and regolith thickens. Results for surface ages are in good agreement with other published crater ages. The existing correlations of large ring structures among various circular mare basins are shown to be based on criteria that are inconsistent and nonstandardized. A means of comparing equivalent ring structures in the different maria is proposed which takes into account the important characteristics of young unflooded basins (Orientale) as well as the progressive development of tectonic and volcanic features within the older flooded maria. Specific geologic aspects of several of the lunar maria are discussed and especially Mare Smythii, because of its great age and significantly different surface morphology. Lunar photographs and maps are shown
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