33,375 research outputs found
Speculative Thread Framework for Transient Management and Bumpless Transfer in Reconfigurable Digital Filters
There are many methods developed to mitigate transients induced when abruptly
changing dynamic algorithms such as those found in digital filters or
controllers. These "bumpless transfer" methods have a computational burden to
them and take time to implement, causing a delay in the desired switching time.
This paper develops a method that automatically reconfigures the computational
resources in order to implement a transient management method without any delay
in switching times. The method spawns a speculative thread when it predicts if
a switch in algorithms is imminent so that the calculations are done prior to
the switch being made. The software framework is described and experimental
results are shown for a switching between filters in a filter bank.Comment: 6 pages, 7 figures, to be presented at American Controls Conference
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Structural Health Monitoring of Composite Airframe
Seminario impartido por el Profesor Aliabadi para describir los Ăşltimos logros obtenidos en el seno de los grupos de investigaciĂłn que dirige en el Imperial College de Londres.Design and maintenance of future airframe composite structures is mainly influenced by the requirement to cope with accidental impact damage. The impact detection and identification strategy for existing structures is of primary importance both in structural health monitoring (SHM) and in non-destructive evaluation (NDE) techniques. Accurately detecting and characterizing an impact event based on sensor data leads us towards condition-based monitoring (CBM), where the subsequent damage can then be detected through active sensing strategies. In this talk, SHM techniques based ultrasonic guided wave will be presented for both passive and active SHM system. Application of these methods to complex stiffened panel will be shown through both experimental measurements and finite element simulations.Universidad de Málaga. Campus de Excelencia Internacional AndalucĂa Tech
More analysts, better ratings: Do rating agencies invest enough in less developed countries?
Rating agencies' track record is good in developed countries but poor in emerging economies. Why? Given the almost-monopolistic structure of the industry, we conjecture that agencies might underinvest in information gathering. We propose an indicator quantifying the agencies' effort to gather information and assess whether greater effort affects rating levels. We detect: (i) absolute underinvestment for non-OECD sovereigns (less effort in spite of greater opaqueness); (ii) relative underinvestment for non-OECD firms compared with OECD ones (though the former receive a larger effort, more intense effort boosts firm ratings in non-OECD countries while depressing them in OECD countries).sovereign risk, credit ratings, rating agencies' effort
A 0.18µm CMOS DDCCII for Portable LV-LP Filters
In this paper a current mode very low voltage (LV) (1V) and low power (LP) (21 µW) differential difference second generation current conveyor (CCII) is presented. The circuit is developed by applying the current sensing technique to a fully balanced version of a differential difference amplifier (DDA) so to design a suitable LV LP integrated version of the so-called differential difference CCII (DDCCII). Post-layout results, using a 0.18µm SMIC CMOS technology, have shown good general circuit performances making the proposed circuit suitable for fully integration in battery portable systems as, for examples, fully differential Sallen-Key bandpass filter
Factorization and escorting in the game-theoretical approach to non-extensive entropy measures
The game-theoretical approach to non-extensive entropy measures of
statistical physics is based on an abstract measure of complexity from which
the entropy measure is derived in a natural way. A wide class of possible
complexity measures is considered and a property of factorization investigated.
The property reflects a separation between the system being observed and the
observer. Apparently, the property is also related to escorting. It is shown
that only those complexity measures which are connected with Tsallis entropy
have the factorization property.Comment: 7 pages, revtex4. For NEXT2005 proceeding
Estimating Multidimensional Persistent Homology through a Finite Sampling
An exact computation of the persistent Betti numbers of a submanifold of
a Euclidean space is possible only in a theoretical setting. In practical
situations, only a finite sample of is available. We show that, under
suitable density conditions, it is possible to estimate the multidimensional
persistent Betti numbers of from the ones of a union of balls centered on
the sample points; this even yields the exact value in restricted areas of the
domain.
Using these inequalities we improve a previous lower bound for the natural
pseudodistance to assess dissimilarity between the shapes of two objects from a
sampling of them.
Similar inequalities are proved for the multidimensional persistent Betti
numbers of the ball union and the one of a combinatorial description of it
The Effect of Rating Agencies on Herd Behaviour
This paper purports to provide some evidence on the effect of rating agencies on herding in financial markets. By means of a laboratory experiment, we investigate the effect and interaction between private and public information. Previous experiments showed that lemmings behaviour can survive in a market context where information is private (Hey and Morone, 2004), and that an experimental market can be very volatile and not efficient in transmitting information (Alfarano et al., 2006). We study experimentally, if socially undesirable behaviour - that survives in a market contest - may be eliminated owing to the presence of rating agencies.herd behaviour; informational cascades; rating agency; bubble
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