A recursive filtering technique for the state estimation of linear systems where the Gaussian assumption is not required for either the plant (process), initial condition, or measurement noise are presented. The appro...
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A recursive filtering technique for the state estimation of linear systems where the Gaussian assumption is not required for either the plant (process), initial condition, or measurement noise are presented. The approach requires the noise to be defined by their higher-order statistics (moments or cumulants). Analogous to the Kalman filter time-update propagation of a covariance matrix, cumulants can be propagated in a similar fashion making use of Kronecker products and the fact that the cumulant of a sum of independent random variables is the sum of the individual cumulants. This allows for a straightforward characterization of the statistics for the likelihood and the prior probability at the time of the measurement update of the filter. An experimental evaluation shows these cumulant-based filters perform better than a default use of a Kalman filter.
The Level 1 Muon Trigger subsystem for BTeV will be implemented using the same architectural building blocks as the BTeV Level 1 Pixel Trigger: pipelined field programmable gate arrays feeding a farm of dedicated proc...
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The Level 1 Muon Trigger subsystem for BTeV will be implemented using the same architectural building blocks as the BTeV Level 1 Pixel Trigger: pipelined field programmable gate arrays feeding a farm of dedicated processing elements. The muon trigger algorithm identifies candidate tracks, and is sensitive to the muon charge (sign);candidate dimuon events are identified by complementary charge track-pairs. To insure that the trigger is operating effectively, the trigger development team is actively collaborating in an independent multi-university research program for reliable, self-aware, fault adaptive behavior in real-time embedded systems (RTES). Key elements of the architecture, algorithm, performance, and engineered reliability are presented.
By engineering a cavity inside a photonic crystal we present a systematic method to engineer the dispersion of a coupled resonator optical waveguide (CROW). By designing a single mode cavity, we demonstrate the design...
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By engineering a cavity inside a photonic crystal we present a systematic method to engineer the dispersion of a coupled resonator optical waveguide (CROW). By designing a single mode cavity, we demonstrate the design and dispersion control of a single mode CROW in the photonic band gap (PBG).
We present data from one-dimensional unshunted Josephson-junction arrays with ground planes, showing resonant behavior for certain values of the critical current. Due to the hysteresis of the current-voltage character...
We present data from one-dimensional unshunted Josephson-junction arrays with ground planes, showing resonant behavior for certain values of the critical current. Due to the hysteresis of the current-voltage characteristics, the number of junction that oscillate on resonance can be controlled. The resonant frequency decreases as more junctions are switched onto the resonance and increases as the array length is increased. We develop a transmission-line model of the arrays that reproduces these experimental observations. We also examine the microscopic origin of this model and compare it to existing models in the literature.
Systematic design of directional couplers in photonic crystals is considered, and three methods to control the coupling length are proposed. Bending of coupled waveguide is considered and optimum frequency of operatio...
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Systematic design of directional couplers in photonic crystals is considered, and three methods to control the coupling length are proposed. Bending of coupled waveguide is considered and optimum frequency of operation to get efficient waveguide coupling and bending is presented.
Rate and diversity impose a fundamental trade-off in space-time coding. High-rate space-time codes come at a cost of lower diversity, and high reliability (diversity) implies a lower rate. We explore a different point...
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Rate and diversity impose a fundamental trade-off in space-time coding. High-rate space-time codes come at a cost of lower diversity, and high reliability (diversity) implies a lower rate. We explore a different point of view where we design high-rate space-time codes that have a high-diversity code embedded within them. This allows a form of communication where the high-rate code opportunistically takes advantage of good channel realizations whereas the embedded high-diversity code ensures that at least part of the information is received reliably. We explore this point of view with design issues, along with some preliminary progress on code constructions and some information-theoretic considerations.
We introduce a time-domain method to simulate the digital signal propagation along on-chip interconnects by solving Maxwell's equations with the Alternating-Direction-Implicit (ADI) method. With this method, we ar...
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We introduce a time-domain method to simulate the digital signal propagation along on-chip interconnects by solving Maxwell's equations with the Alternating-Direction-Implicit (ADI) method. With this method, we are able to resolve the large scale (i.e. on-chip electromagnetic wave propagation) and fine scale (i.e. skin depth and substrate current) structure in the same simulation, and the simulation time step is not limited by the Courant condition. The simulations allow us to calculate in detail parasitic current flow inside the substrate; propagation losses; skin-depth; and dispersion of digital signals on non-ideal interconnects. We have found considerable substrate currents and losses that depend on the substrate doping.
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