1,579 research outputs found
Planetary circulations in the presence of transient and self-induced heating
The research program focuses on large-scale circulations and their interaction with the global convective pattern. An 11-year record of global cloud imagery and contemporaneous fields of motion and temperature have been used to investigate organized convection and coherent variability of the tropical circulation operating on intraseasonal time scales. This study provides a detailed portrait of tropical variability associated with the so-called Madden-Julian Oscillation (MJO). It reveals the nature, geographical distribution, and seasonality of discrete convective signal, which is a measure of feedback between the circulation and the convective pattern. That discrete spectral behavior has been evaluated in light of natural variability of the ITCZ associated with climatological convection. A composite signature of the MJO, based on cross-covariance statistics of cloud cover, motion, and temperature, has been constructed to characterize the lifecycle of the disturbance in terms of these properties. The composite behavior has also been used to investigate the influence the MJO exerts on the zonal-mean circulation and the involvement of the MJO in transfers of momentum between the atmosphere and the solid Earth. The aforementioned observational studies have led to the production of two animations. One reveals the convective signal in band-pass filtered OLR and compares it to climatological convection. The other is a 3-dimensional visualization of the composite lifecycle of the MJO. With a clear picture of the MJO in hand, feedback between the circulation and the convective pattern can be diagnosed meaningfully in numerical simulations. This process is being explored in calculations with the linearized primitive equations on the sphere in the presence of realistic stability and shear. The numerical framework represents climatological convection as a space-time stochastic process and wave-induced convection in terms of the vertically-integrated moisture flux convergence. In these calculations, frictional convergence near the equator emerges as a key to feedback between the circulation and the convective pattern. At low latitudes, nearly geostrophic balance in the boundary layer gives way to frictional balance. This shifts the wave-induced convection into phase with the temperature anomaly and allows the attending heating to feed back positively onto the circulation. The calculations successfully reproduce the salient features of the MJO. They are being used to understand the growth and decay phases of the composite lifecycle and the conditions that favor amplification of the MJO
Apollo Lunar Sounder digital data deconvolution
The purpose of the work reported on herein was to demonstrate the possibility of enhancing the subsurface feature detection probability by digital processing and filtering.Rolando Jordan.Introduction -- Description of the procedure -- Phase error detection procedure -- Conclusion
The "Flight Testing" Graduate Course at Politecnico di Milano
This paper describes the current status of the “Flight Testing” graduate course held at the Politecnico di Milano as an elective subject in its Aeronautical Engi-neering MSc curriculum. The course, delivered each year, has reached its 10th anniver-sary in 2015. Nearly 120 students passed the course to date, most of them upon submis-sion and presentation of a flight test report concerning a real flight test mission carried out by the student in person. In fact, the unique characteristic of this course is the provi-sion of a complete experience in which each student is requested to design, perform and report on a real flight test of a manned aircraft, acting as a Flight Test Engineer under all respects. The conditions of the flight test experience and two flight test campaigns are described, reporting on the latest updates in the FTI system, which now features a fully functional telemetry capability
Energy management system optimization based on an LSTM deep learning model using vehicle speed prediction
The energy management of a Hybrid Electric Vehicle (HEV) is a global optimization problem, and its optimal solution inevitably entails knowing the entire mission profile. The exploitation of Vehicle-to-Everything (V2X) connectivity can pave the way for reliable short-term vehicle speed predictions. As a result, the capabilities of conventional energy management strategies can be enhanced by integrating the predicted vehicle speed into the powertrain control strategy. Therefore, in this paper, an innovative Adaptation algorithm uses the predicted speed profile for an Equivalent Consumption Minimization Strategy (A-V2X-ECMS). Driving pattern identification is employed to adapt the equivalence factor of the ECMS when a change in the driving patterns occurs, or when the State of Charge (SoC) experiences a high deviation from the target value. A Principal Component Analysis (PCA) was performed on several energetic indices to select the ones that predominate in characterizing the different driving patterns. Long Short-Term Memory (LSTM) deep neural networks were trained to choose the optimal value of the equivalence factor for a specific sequence of data (i.e., speed, acceleration, power, and initial SoC). The potentialities of the innovative A-V2X-ECMS were assessed, through numerical simulation, on a diesel Plug-in Hybrid Electric Vehicle (PHEV) available on the European market. A virtual test rig of the investigated vehicle was built in the GT-SUITE software environment and validated against a wide database of experimental data. The simulations proved that the proposed approach achieves results much closer to optimal than the conventional energy management strategies taken as a reference
Real parallelisms
A garden of parallelisms in are constructed,where is the field of real numbers
The location of the hot spot in a grounded convex conductor
Abstract. We investigate the location of the (unique) hot spot in a convex heat conductor with unitary initial temperature and with boundary grounded at zero temperature. We present two methods to locate the hot spot: the for-mer is based on ideas related to the Alexandrov-Bakelmann-Pucci maximum principle and Monge-Ampère equations; the latter relies on Alexandrov’s re-flection principle. We then show how such a problem can be simplified in case the conductor is a polyhedron. Finally, we present some numerical computa-tions. 1
Parameter Estimation with Mixed-State Quantum Computation
We present a quantum algorithm to estimate parameters at the quantum
metrology limit using deterministic quantum computation with one bit. When the
interactions occurring in a quantum system are described by a Hamiltonian , we estimate by zooming in on previous estimations and by
implementing an adaptive Bayesian procedure. The final result of the algorithm
is an updated estimation of whose variance has been decreased in
proportion to the time of evolution under H. For the problem of estimating
several parameters, we implement dynamical-decoupling techniques and use the
results of single parameter estimation. The cases of discrete-time evolution
and reference-frame alignment are also discussed within the adaptive approach.Comment: 12 pages. Improved introduction and technical details moved to
Appendi
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