Average Rate of Downlink Heterogeneous Cellular Networks over Generalized Fading Channels - A Stochastic Geometry Approach

In this paper, we introduce an analytical framework to compute the average rate of downlink heterogeneous cellular networks. The framework leverages recent application of stochastic geometry to other-cell interference modeling and analysis. The heterogeneous cellular network is modeled as the superposition of many tiers of Base Stations (BSs) having different transmit power, density, path-loss exponent, fading parameters and distribution, and unequal biasing for flexible tier association. A long-term averaged maximum biased-received-power tier association is considered. The positions of the BSs in each tier are modeled as points of an independent Poisson Point Process (PPP). Under these assumptions, we introduce a new analytical methodology to evaluate the average rate, which avoids the computation of the Coverage Probability (Pcov) and needs only the Moment Generating Function (MGF) of the aggregate interference at the probe mobile terminal. The distinguishable characteristic of our analytical methodology consists in providing a tractable and numerically efficient framework that is applicable to general fading distributions, including composite fading channels with small- and mid-scale fluctuations. In addition, our method can efficiently handle correlated Log-Normal shadowing with little increase of the computational complexity. The proposed MGF-based approach needs the computation of either a single or a two-fold numerical integral, thus reducing the complexity of Pcov-based frameworks, which require, for general fading distributions, the computation of a four-fold integral.Comment: Accepted for publication in IEEE Transactions on Communications, to appea

Do tax distortions lead to more indeterminacy? A New Keynesian perspective

Following the recent developments of the literature on stabilization policies, this paper investigates the effect of tax distortions on equilibrium determinacy in a New Keynesian economy with rule-of-thumb consumers and capital accumulation. In particular, we focus on the inter-action between monetary policy and tax distortions in supporting the saddle-path equilibrium under the assumptions of balanced budget and monetary policy satisfying a Taylor rule.rule-of-thumb consumers, equilibrium determinacy, fiscal and monetary policy inter-actions, and tax distortions

Policy Uncertainty, Symbiosis, and the Optimal Fiscal and Monetary Conservativeness

This paper extends a well-known macroeconomic stabilization game between monetary and fiscal authorities introduced by Dixit and Lambertini (American Economic Review, 93: 1522-1542) to multiplicative (policy) uncertainty. We find that even if fiscal and monetary authorities share a common output and inflation target (i.e. the symbiosis assumption), the achievement of the common targets is no longer guaranteed; under multiplicative uncertainty, in fact, a time consistency problem arises unless policymakers� output target is equal to the natural level.Monetary-fiscal policy interactions, uncertainty, symbiosis.

Policy Uncertainty, Symbiosis, and the Optimal Fiscal and Monetary Conservativeness

This paper extends the stabilization game between monetary and fiscal authorities to the case of multiplicative (model) uncertainty. In this context, the “symbiosis assumption”, i.e. fiscal and monetary policy share the same ideal targets, no longer guarantees the achievement of ideal output and inflation, unless the ideal output is equal to its natural level. A time consistency problem arises.Monetary-fiscal policy interactions, uncertainty, symbiosis.

P-V-T Behavior of 2,3,3,3-Tetrafluoroprop-1-ene (HFO-1234yf) in the Vapor Phase from (243 to 373) K

The P-V-T properties of 2,3,3,3-tetrafluoroprop-1-ene (CF 3 CFdCH 2 , HFO-1234yf), an environmentally friendly refrigerant, were measured using a constant volume apparatus. Measurements were carried out at temperatures from (243 to 373) K and at pressures from (84 to 3716) kPa. A total of 136 experimental points, taken along 12 isochores, were obtained. Our experimental results were compared with a preliminary equation of state. The measurements were also regressed to the Martin-Hou equation of state. No other data on this fluid were found in the literature for the superheated region

Fiscal Policy under Balanced Budget and Indeterminacy: A New Keynesian Perspective

We investigate the effect of fiscal policy on equilibrium determinacy in a New Keynesian economy with rule-of-thumb (liquidity constrained) consumers and capital accumulation by focusing on the inter-action between monetary policy and taxation under the assumption of balanced budget. Our main finding is that taxation of firms� monopoly rents reduces the parameter range within which the Taylor principle is insufficient to guarantee equilibrium determinacy; hence it supports the determinacy of the rational expectation equilibrium.Rule-of-thumb consumers, equilibrium determinacy, fiscal and monetary policy inter-actions, tax distortions, balanced government budget.

Equivalence of gradient flows and entropy solutions for singular nonlocal interaction equations in 1D

We prove the equivalence between the notion of Wasserstein gradient flow for a one-dimensional nonlocal transport PDE with attractive/repulsive Newtonian potential on one side, and the notion of entropy solution of a Burgers-type scalar conservation law on the other. The solution of the former is obtained by spatially differentiating the solution of the latter. The proof uses an intermediate step, namely the $L^2$ gradient flow of the pseudo-inverse distribution function of the gradient flow solution. We use this equivalence to provide a rigorous particle-system approximation to the Wasserstein gradient flow, avoiding the regularization effect due to the singularity in the repulsive kernel. The abstract particle method relies on the so-called wave-front-tracking algorithm for scalar conservation laws. Finally, we provide a characterization of the sub-differential of the functional involved in the Wasserstein gradient flow

Resilience, crisis contagion, and vulnerability in Central Europe and the Baltics

The recent financial crisis had serious worldwide impacts. Initial resilience and good past performances led to the illusion that the Central and Eastern European (CEE) region was able to decouple from developments in advanced economies. This initial illusion was however immediately denied since the crisis spread to that region just with a lag. The CEE region was, in fact, suddenly placed at the epicenter of the emerging market crisis. Further, the consequences of the crisis were not uniform among countries of the CEE region. Strong cross-country disparities in the resistance and recovery capacities have been observed. Focusing on a CEE sub-region, the Central Europe and the Baltics (CEB), our research project aims to analyze and disentangle the resilience performance to the 2008 financial crisis within countries of this region according to their shock isolation and absorptive capacities. We develop a new methodology to investigate two important dimensions of resilience, namely recovery and resistance. The latter can be defined as the relative vulnerability or sensitivity of economies within CEB region to disturbances and disruptions, whereas the former is the speed and extent of recovery from such a disruption or recession. Our methodology is based on Bayesian estimation techniques for general equilibrium models. We build and estimate a DSGE model for a small-open economy, which features nominal wage and price rigidities, as well as financial frictions in the form of liquidity-constrained households and limited access to deposits for the bank system. Then we group our parameter estimates in two sets: structural parameters and stochastic structure. The former individuates the deep parameters affecting the economic recovery capacities after stochastic disturbances (innovations) occur; the latter governs the innovation distributions and their intrinsic persistence. Accordingly, we study the relative differences across CEB economies using Principal Component Analysis (PCA), obtaining synthetic orthogonal indexes of these differences in a parsimonious way. Finally, we use the two sets to compare the relative recovery (resistance) country performances of a single country to those of a hypothetical economy characterized by a CEB average structural (stochastic) set of estimated parameters. Precisely, considering estimated parameters as variables of a cross-sectional dataset organized by country, we first look at national differences considering as reference a hypothetical country, where there are no distortions and/or unaffected by disturbances; second we use, as reference, a hypothetical average country, built on the estimated parameter means.JRC.B.3-Territorial Developmen

The CFD code karalis

Karalis is a paralle MPI, Finite-Volume, multiblock CFD code which solves the fully compressible Euler and Navier-Stokes equations where all couplings between dynamics and thermodynamics are allowed. This the most general mathematical model for all fluid flows. The code solves the coupled system of continuity, momentum and full energy equation for the velocity components, pressure and temperature. Once, u, v, w, p are and T are updated, arbitrary thermodynamics is supplied. The second order Roe’s upwind TVD scheme is used to compute convective fluxes through the Finite-Volume cell interfaces. A V-cycle Coarse Grid Correction Multi-Grid algorithm is used, together with a 5-stage Runge-Kutta explicit time-marching method, to accelerate convergence to a steady state. This formulation, typical of aerodynamic flows, shows an eccellent efficiency even for incompressible flows as well as for flows of incompressible fluids (typically buoyancy flows), once equipped with a preconditioner. Merkel’s preconditioner has been chosen because it can be easily formulated for arbitrary equations of state given as a functional relation of two independent thermodynamic variables (typically the pressure p and the temperature T), or even in tabular form, read in as an input file and used with bilinear interpolation. Karalis implement two among the most popular turbulence models, namely the one-equation model by Spalart and Allmaras and the two-equations model by Wilcox, the k-ω model, which allow a good compromise between accuracy, robustness and stability of turbulent calculations. Code validation is presented for some typical benchmark test cases of incompressible fluid dynamics. Comparison with solutions obtained with a few popular commercial CFD codes is also presented

A stochastic estimated version of the Italian dynamic General Equilibrium Model (IGEM)

We estimate with Bayesian techniques the Italian dynamic General Equilibrium Model (IGEM), which has been developed at the Italian Treasury Department, Ministry of Economy and Finance, to assess the effects of alter-native policy interventions. We analyze and discuss the estimated effects of various shocks on the Italian economy. Compared to the calibrated version used for policy analysis, we find a lower wage rigidity and higher adjustment costs. The degree of prices and wages indexation to past inflation is much smaller than the indexation level assumed in the calibrated model. No substantial difference is found in the estimated monetary parameters. Estimated fiscal multipliers are slightly smaller than those obtained from the calibrated version of the model