Rules versus discretion in fiscal policy

This paper purports to apply the Kydland-Prescott framework of dynamic inconsistency to the case of fiscal policy, by considering the trade-off between output and debt stabilization. The Government budget constraint provides the link between debt dynamics and the level of activity, influenced by fiscal policy. Contrary to what happens in the monetary policy framework, however, a commitment is not always superior to discretion, even in the absence of uncertainty, but only when the public debt-GDP ratio is sufficiently large. The introduction of uncertainty, as usual, implies a reduction in the net benefit generated by the adoption of a fixed rule.rules, discretion, time inconsistency, fiscal policy

Thermodynamic Limit for Mean-Field Spin Models

If the Boltzmann-Gibbs state $\omega_N$ of a mean-field $N$-particle system with Hamiltonian $H_N$ verifies the condition $$\omega_N(H_N) \ge \omega_N(H_{N_1}+H_{N_2})$$ for every decomposition $N_1+N_2=N$, then its free energy density increases with $N$. We prove such a condition for a wide class of spin models which includes the Curie-Weiss model, its p-spin generalizations (for both even and odd p), its random field version and also the finite pattern Hopfield model. For all these cases the existence of the thermodynamic limit by subadditivity and boundedness follows.Comment: 15 pages, few improvements. To appear in MPE

Pansharpening techniques to detect mass monument damaging in Iraq

The recent mass destructions of monuments in Iraq cannot be monitored with the terrestrial survey methodologies, for obvious reasons of safety. For the same reasons, it’s not advisable the use of classical aerial photogrammetry, so it was obvious to think to the use of multispectral Very High Resolution (VHR) satellite imagery. Nowadays VHR satellite images resolutions are very near airborne photogrammetrical images and usually they are acquired in multispectral mode. The combination of the various bands of the images is called pan-sharpening and it can be carried on using different algorithms and strategies. The correct pansharpening methodology, for a specific image, must be chosen considering the specific multispectral characteristics of the satellite used and the particular application. In this paper a first definition of guidelines for the use of VHR multispectral imagery to detect monument destruction in unsafe area, is reported. The proposed methodology, agreed with UNESCO and soon to be used in Libya for the coastal area, has produced a first report delivered to the Iraqi authorities. Some of the most evident examples are reported to show the possible capabilities of identification of damages using VHR images

Anti-Fall: A Non-intrusive and Real-time Fall Detector Leveraging CSI from Commodity WiFi Devices

Fall is one of the major health threats and obstacles to independent living for elders, timely and reliable fall detection is crucial for mitigating the effects of falls. In this paper, leveraging the fine-grained Channel State Information (CSI) and multi-antenna setting in commodity WiFi devices, we design and implement a real-time, non-intrusive, and low-cost indoor fall detector, called Anti-Fall. For the first time, the CSI phase difference over two antennas is identified as the salient feature to reliably segment the fall and fall-like activities, both phase and amplitude information of CSI is then exploited to accurately separate the fall from other fall-like activities. Experimental results in two indoor scenarios demonstrate that Anti-Fall consistently outperforms the state-of-the-art approach WiFall, with 10% higher detection rate and 10% less false alarm rate on average.Comment: 13 pages,8 figures,corrected version, ICOST conferenc

Design Of An Induction Probe For Simultaneous Measurements Of Permittivity And Resistivity

In this paper, we propose a discussion of the theoretical design and move towards the development and engineering of an induction probe for electrical spectroscopy which performs simultaneous and non invasive measurements on the electrical RESistivity \rho and dielectric PERmittivity \epsilon r of non-saturated terrestrial ground and concretes (RESPER probe). In order to design a RESPER which measures \rho and \epsilon r with inaccuracies below a prefixed limit (10%) in a band of low frequencies (LF) (B=100kHz), the probe should be connected to an appropriate analogical digital converter (ADC), which samples in uniform or in phase and quadrature (IQ) mode, otherwise to a lock-in amplifier. The paper develops only a suitable number of numerical simulations, using Mathcad, which provide the working frequencies, the electrode-electrode distance and the optimization of the height above ground minimizing the inaccuracies of the RESPER, in galvanic or capacitive contact with terrestrial soils or concretes, of low or high resistivity. As findings of simulations, we underline that the performances of a lock-in amplifier are preferable even when compared to an IQ sampling ADC with high resolution, under the same operating conditions. As consequences in the practical applications: if the probe is connected to a data acquisition system (DAS) as an uniform or an IQ sampler, then it could be commercialized for companies of building and road paving, being employable for analyzing "in situ" only concretes; otherwise, if the DAS is a lock-in amplifier, the marketing would be for companies of geophysical prospecting, involved to analyze "in situ" even terrestrial soils.Comment: 37 pages, 7 figures, 3 table

The EPRL intertwiners and corrected partition function

Do the SU(2) intertwiners parametrize the space of the EPRL solutions to the simplicity constraint? What is a complete form of the partition function written in terms of this parametrization? We prove that the EPRL map is injective for n-valent vertex in case when it is a map from SO(3) into SO(3)xSO(3) representations. We find, however, that the EPRL map is not isometric. In the consequence, in order to be written in a SU(2) amplitude form, the formula for the partition function has to be rederived. We do it and obtain a new, complete formula for the partition function. The result goes beyond the SU(2) spin-foam models framework.Comment: RevTex4, 15 pages, 5 figures; theorem of injectivity of EPRL map correcte

Electronic density contours and gravity waves

A campaign of ionospheric vertical sounding with an interval of 10 minutes between all the ionograms was performed in November 1995 in the station of Rome. High-repetition soundings are more useful than the routine soundings for a more precise analysis of the MSTIDs. Isodensity contours of real height vs. time were obtained. The periods of oscillations observed and the upward phase propagation suggest the existence of gravity waves in the ionosphere

Real Time 3D Ionospheric Modelling with Ray Tracing Application over Mediterranean Area

This poster deals with some practical examples of instantaneous 3D modelling of regional ionosphere, based on ionosondes data from the Istituto Nazionale di Geofisica e Vulcanologia, INGV. Characteristic anchor points have been chosen for each ionospheric region. These points are joint by an adaptive ionospheric profiler derived from the one used in Autoscala. For the F2 region the anchor point is given by the real height hmF2 of the layer and its critical frequency foF2. These values are obtained basing on the observed heights (hmF2ROME[OBS] and hmF2GIBILMANNA[OBS]) and critical frequencies (foF2ROME[OBS] and foF2GIBILMANNA[OBS]) of the F2 layer, which are compared with the corresponding monthly median given by CCIR maps using Shimazaki’s formulation. The differences dhmF2ROME = hmF2ROME[OBS] - hmF2ROME[CCIR] dhmF2GIBILMANNA = hmF2 GIBILMANNA [OBS] - hmF2 GIBILMANNA [CCIR] are thus computed and used in Kriging method to update the values given by CCIR maps. For the F1 region the critical frequency is derived form a solar zenith angle dependent model adjusted to match the values of foF1 measured in Rome and Gibilmanna. For the E region the height is set to 110 km, while the critical frequency is estimated by a standard solar zenith angle and solar activity dependent model. The model produces as an output a 3D matrix which can be profitably used as an input for a Matlab/Fortran based ray tracing program recently developed at INGV