Where does ramp collide?

In structural geology, a ramp is the part of a thrust fault that climbs steeply up through the rock layers, connecting the gently dipping flats that run along weak horizons, the ramp-flat geometry that governs how thrust sheets stack. Boyer and Elliott's 1982 Thrust systems set out this anatomy of ramps and flats. The referent is a fault-surface segment in the Earth's crust, described by its dip and cutoff angles, and it has nothing to do with a highway on-ramp or a mathematical ramp signal beyond the shared image of an incline.[1]

Unit

The inclined fault segment, described by its dip and the angle at which it cuts bedding

Recovery means

Not applicable

Measured by

Mapped from cutoff angles, fault geometry, and the offset of marker beds across the ramp

In signals and systems, the ramp is the elementary function that is zero until an onset and then rises linearly with time (the running integral of the unit step), used as a standard test input and a building block for more complex signals. Oppenheim, Willsky, and Nawab's Signals & Systems presents it among the basic continuous-time signals. The referent is a mathematical function of time, characterised by its slope, and it is a different construct from a geological fault ramp or a freeway ramp; the same shape underlies the rectified-linear (ReLU) unit used in machine learning (that connection is not drawn from the cited source).[2]

Unit

A function rising linearly with a given slope after an onset time (the integral of the step)

Recovery means

Not applicable

Measured by

Characterised by its slope and onset; used as a test input to probe a system's response

In traffic engineering, a ramp is the short roadway connecting a surface road to a freeway, and ramp metering regulates how fast vehicles are released from the on-ramp onto the mainline so that the freeway does not tip into congestion. Papageorgiou and Kotsialos's 2002 Freeway ramp metering: An overview surveys the control strategies. The referent is a physical connector and its inflow control on a road network, measured in metered flow and resulting mainline conditions, distinct from a fault ramp or a ramp signal.[3]

Unit

The on-ramp and its metered release rate of vehicles onto the mainline

Recovery means

By holding ramp inflow below mainline capacity, metering keeps the freeway in free flow or helps it recover from breakdown

Measured by

Tracked by metered on-ramp flow, ramp queue, and the resulting mainline speed and throughput