9,621 research outputs found
Event-Triggered Observers and Observer-Based Controllers for a Class of Nonlinear Systems
In this paper, we investigate the stabilization of a nonlinear plant subject
to network constraints, under the assumption of partial knowledge of the plant
state. The event triggered paradigm is used for the observation and the control
of the system. Necessary conditions, making use of the ISS property, are given
to guarantee the existence of a triggering mechanism, leading to asymptotic
convergence of the observer and system states. The proposed triggering
mechanism is illustrated in the stabilization of a robot with a flexible link
robot.Comment: Proceedings of the 2015 American Control Conference - ACC 201
Triggering an aurora
Ambient ionospheric electron density studied as triggering mechanism of aurora
Pulsed high-power arc heater with improved cathode and triggering mechanism
System employs pulsed, constricted arc heater capable of multi-MW power, permitting quasi-stationary flow conditions during latter half of pulse of about 5 msec. System description is given
Ocean Rossby waves as a triggering mechanism for primary Madden-Julian events
The Madden–Julian Oscillation (MJO) is sporadic, with episodes of cyclical activity interspersed with inactive periods. However, it remains unclear what may trigger a Madden–Julian (MJ) event which is not immediately preceded by any MJO activity: a ‘primary’ MJ event. A combination of case-studies and composite analysis is used to examine the extent to which the triggering of primary MJ events might occur in response to ocean dynamics. The case-studies show that such events can be triggered by the arrival of a downwelling oceanic equatorial Rossby wave, which is shown to be associated with a deepening of the mixed layer and positive sea-surface temperature (SST) anomalies of the order of 0.5–1 °C. These SST anomalies are not attributable to forcing by surface fluxes which are weak for the case-studies analysed. Furthermore, composite analysis suggests that such forcing is consistently important for triggering primary events. The relationship is much weaker for successive events, due to the many other triggering mechanisms which operate during periods of cyclical MJO activity. This oceanic feedback mechanism is a viable explanation for the sporadic and broadband nature of the MJO. Additionally, it provides hope for forecasting MJ events during periods of inactivity, when MJO forecasts generally exhibit low skill
Sensitivity of the Static Earthquake Triggering Mechanism to Elastic Heterogeneity and Main Event Slip
This paper has evolved out of our previous work on static stress transfer,
where we used the full-space elastostatic Green's tensor to compute the Coulomb
stress transfer impact of the Landers earthquake on the Hector Mine event. In
this work, we use the elastostatic Green's tensor for an arbitrary layered
Earth model with free-surface boundary conditions to study the impact of
elastic heterogeneity as well as source-fault slip and geometry on the stress
transfer mechanism. Slip distribution and fault geometry of the source have a
significant impact on the stress transfer, especially in case of spatially
extended triggered events. Maximization of the Coulomb stress transfer function
for known aftershocks provides a mechanism for inverting for the source event
slip. Heterogeneity of the elastic earth parameters is shown to have a
sizeable, but lower-magnitude, impact on the static stress transfer in 3D. The
analysis is applied to Landers/Hector Mine and 100 small "aftershocks" of the
Landers event. A computational toolkit is provided for the study of static
stress transfer for arbitrary source and receiver faults in layered Earth.Comment: 26 pages, 32 figure
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