1,569 research outputs found
Multi-objective design of robust flight control systems
A multi–objective evolutionary algorithm is used in the framework of H1 control theory
to find the controller gains that minimize a weighted combination of the infinite–norm
of the sensitivity function (for disturbance attenuation requirements) and complementary
sensitivity function (for robust stability requirements). After considering a single operating
point for a level flight trim condition of a F-16 fighter aircraft model, two different
approaches will then be considered to extend the domain of validity of the control law: 1)
the controller is designed for different operating points and gain scheduling is adopted; 2)
a single control law is designed for all the considered operating points by multiobjective
minimisation. The two approaches are analyzed and compared in terms of effectiveness of
the design method and resulting closed loop performance of the system
Vacuum-matter transition of solar neutrino oscillations with the Borexino experiment
Thanks to the excellent levels of achieved radiopurity and to the accurate data analysis techniques, Borexino has performed the first real time measurement of the 7Be solar neutrino flux. The efficient software rejection of cosmogenic background also allows to investigate the recoiled electron spectrum induced by 8B solar neutrinos down to 3 MeV, the lowest energy threshold ever reached in
real time detection. This is the first observation of solar 8B neutrinos in a liquid scintillator detector. For the first time, the same apparatus can measure the two different oscillation regions (vacuum-driven and matter-enhanced) predicted by the MSW-LMA model. Borexino also quotes the ratio between the survival probabilities,
corresponding to 1.93 ± 0.75, validating the presence of the transition region predicted by the MSW-LMA solution
Evolutionary design of a full-envelope full-authority flight control system for an unstable high-performance aircraft
The use of an evolutionary algorithm in the framework of H1 control theory is being considered as a means for synthesizing controller gains that minimize a weighted combination of the infinite norm of the sensitivity function (for disturbance attenuation requirements) and complementary sensitivity function (for robust stability requirements) at the same time. The case study deals with a complete full-authority longitudinal control system for an unstable high-performance jet aircraft featuring (i) a stability and control augmentation system and (ii) autopilot functions (speed and altitude hold). Constraints on closed-loop response are enforced, that representing typical requirements on airplane handling qualities, that makes the control law synthesis process more demanding. Gain scheduling is required, in order to obtain satisfactory performance over the whole flight envelope, so that the synthesis is performed at different reference trim conditions, for several values of the dynamic pressure, used as the scheduling parameter. Nonetheless, the dynamic behaviour of the aircraft may exhibit significant variations when flying at different altitudes, even for the same value of the dynamic pressure, so that a trade-off is required between different feasible controllers synthesized at different altitudes for a given equivalent airspeed. A multiobjective search is thus considered for the determination of the best suited solution to be introduced in the scheduling of the control law. The obtained results are then tested on a longitudinal non-linear model of the aircraft
Future large-scale water-Cherenkov detector
MEMPHYS (MEgaton Mass PHYSics) is a proposed large-scale water-Cherenkov
experiment to be performed deep underground. It is dedicated to nucleon decay
searches and the detection of neutrinos from supernovae, solar, and atmospheric
neutrinos, as well as neutrinos from a future beam to measure the CP violating
phase in the leptonic sector and the mass hierarchy. This paper provides an
overview of the latest studies on the expected performance of MEMPHYS in view
of detailed estimates of its physics reach, mainly concerning neutrino beams
Study of the performance of a large scale water-Cherenkov detector (MEMPHYS)
MEMPHYS (MEgaton Mass PHYSics) is a proposed large-scale water Cherenkov
experiment to be performed deep underground. It is dedicated to nucleon decay
searches, neutrinos from supernovae, solar and atmospheric neutrinos, as well
as neutrinos from a future Super-Beam or Beta-Beam to measure the CP violating
phase in the leptonic sector and the mass hierarchy. A full simulation of the
detector has been performed to evaluate its performance for beam physics. The
results are given in terms of "Migration Matrices" of reconstructed versus true
neutrino energy, taking into account all the experimental effects.Comment: Updated after JCAP's referee's comment
On continuation-passing transformations and expected cost analysis
We define a continuation-passing style (CPS) translation for a typed \u3bb-calculus with probabilistic choice, unbounded recursion, and a tick operator - for modeling cost. The target language is a (non-probabilistic) \u3bb-calculus, enriched with a type of extended positive reals and a fixpoint operator. We then show that applying the CPS transform of an expression M to the continuation \u3bb v. 0 yields the expected cost of M. We also introduce a formal system for higher-order logic, called EHOL, prove it sound, and show it can derive tight upper bounds on the expected cost of classic examples, including Coupon Collector and Random Walk. Moreover, we relate our translation to Kaminski et al.'s ert-calculus, showing that the latter can be recovered by applying our CPS translation to (a generalization of) the classic embedding of imperative programs into \u3bb-calculus. Finally, we prove that the CPS transform of an expression can also be used to compute pre-expectations and to reason about almost sure termination
Interactions in Mobile Sound and Music Computing
none4siopenGeronazzo M.; Avanzini F.; Fontana F.; Serafin S.Geronazzo, M.; Avanzini, F.; Fontana, F.; Serafin, S
First report of a Late Jurassic lizard-like footprint (Asturias, Spain)
This report describes an isolated footprint preserved as a natural cast (convex hyporelief) from the Lastres Fm. (Late Jurassic) of northern Spain. The track consists of a small isolated pentadactyl ectaxonic right manus footprint. It is very asymmetric, plantigrade, with digits and palm deeply marked on the substrate. Digit IV is the longest, digits II and I are nearly equal in length and only a little shorter than III and IV. The footprint morphology is typical of a lizard – like or “lacertoid” track .The general outline of the footprint, the width to length ratio approximately equal to 1, the marked plantigrady and the substantial similarity in length of digits IV-I are coherent with a Rhynchosauroidea manual print. The global record of Rhynchosauroides ichnogenus shows that this specimen represents the latest occurrence of the ichnogenus. The most probable trackmaker was possibly a rhyncocephalian reptile.Se describe una huella de mano aislada, preservada como contramolde natural (hiporrelieve convexo) de la Formacion Lastres (Jurasico Superior) del N de Espana. La icnita, aislada, pentadactila, ectaxonica y de pequeno tamano, es atribuida a una mano derecha. Es muy asimetrica y plantigrada, con los dedos y la palma profundamente impresos en el sustrato. El dedo IV es el mas largo, mientras que el II y el I son casi iguales en longitud y solamente un poco mas cortos que el III y el IV. La morfologia de la huella es tipica de un lagarto o “lacertoide”. El contorno de la huella, la relacion longitud/anchura en torno a 1, la longitud similar de los dedos I-IV y el hecho de que sea claramente plantigrada son rasgos coherentes con una huella de mano de un Rhynchosauroidea. El registro global de Rhynchosauroides indica que el ejemplar asturiano representa la evidencia mas reciente de este icnogenero. El autor de la huella fue probablemente un reptil rincocefalo
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