Robust Adaptive Congestion Control for Next Generation Networks

This paper deals with the problem of congestion control in a next-generation heterogeneous network scenario. The algorithm runs in the 'edge' routers (the routers collecting the traffic between two different networks) with the aim of avoiding congestion in both the network and the edge routers. The proposed algorithm extends congestion control algorithms based on the Smith's principle: i) the controller, by exploiting on-line estimates via probe packets, adapts to the delay and rate variations; ii) the controller assures robust stability in the presence of time-varying delays

Control-Based Resource Management Procedures for Satellite Networks

This paper describes the resource management of a DVBRCS geostationary satellite network. The functional modules of the access layer aim at efficiently exploiting the link resources while assuring the contracted Quality of Service (QoS) to the traffic entering the satellite network. The main novelty is the integration between the Connection Admission Control and the Congestion Control procedures. Both them exploit the estimation of the traffic load, performed by a Kalman filter. The proposed solution has been analysed via computer simulations, which confirmed their effectiveness

The Non-Superneutrality of Money and its Distributional Effects when Agents are Heterogeneous and Capital Markets are Imperfect

In this paper we develop an OLG model with heterogeneous agents, money and bequests, introducing occupational choice and financing constraints when capital markets are imperfect. We show how, under appropriate conditions, all the moments of the distribution are affected by changes in money growth. More precisely, if capital markets are imperfect and heterogeneous agents are liquidity constrained, investment in fixed capital is not efficient and aggregate wages and profits depend on the availability of loanable funds. An increase in money growth may imply a more efficient aggregate investment. Therefore aggregate product and wealth positively depend on an acceleration in money growth.

Large-Scale information extraction from textual definitions through deep syntactic and semantic analysis

We present DEFIE, an approach to large-scale Information Extraction (IE) based on a syntactic-semantic analysis of textual definitions. Given a large corpus of definitions we leverage syntactic dependencies to reduce data sparsity, then disambiguate the arguments and content words of the relation strings, and finally exploit the resulting information to organize the acquired relations hierarchically. The output of DEFIE is a high-quality knowledge base consisting of several million automatically acquired semantic relations

SupWSD: a flexible toolkit for supervised word sense disambiguation

In this demonstration we present SupWSD, a Java API for supervised Word Sense Disambiguation (WSD). This toolkit includes the implementation of a state-of-the-art supervised WSD system, together with a Natural Language Processing pipeline for preprocessing and feature extraction. Our aim is to provide an easy-to-use tool for the research community, designed to be modular, fast and scalable for training and testing on large datasets. The source code of SupWSD is available at http://github.com/SI3P/SupWSD

Heterogeneity and Aggregation in a Financial Accelerator Model

In this paper we present a macroeconomic model in which changes in the variance (and higher moments of the distribution) of firm's financial conditions - i.e. "distributive shocks" - are bound to play a crucial role in the determination of output fluctuations. Firms differ by degree of financial robustness, which affects (optimal) investment in a bankruptcy risk context (à la Greenwald-Stiglitz). As to households, for the sake of simplicity, we assume that they are homogeneous in every respect so that we can adopt the representative agent hypothesis. We can explore the properties of the macro-dynamic model either via the study of the two-dimensional map defining the laws of motion of the average equity ratio and of the variance of the distribution or via simulations in a multiagent framework.

A look at the relationship between industrial dynamics and aggregate fluctuations

The firmly established evidence of right-skewness of the firms’ size distribution is generally modelled recurring to some variant of the Gibrat’s Law of Proportional Effects. In spite of its empirical success, this approach has been harshly criticized on a theoretical ground due to its lack of economic contents and its unpleasant long-run implications. In this chapter we show that a right-skewed firms’ size distribution, with its upper tail scaling down as a power law, arises naturally from a simple choice-theoretic model based on financial market imperfections and a wage setting relationship. Our results rest on a multi-agent generalization of the prey-predator model, firstly introduced into economics by Richard Goodwin forty years ago.Firm size; Prey-predator model; Business Fluctuations

Asset Prices and Monetary Policy: A New View of the Cost Channel

Should the central bank act to prevent "excessive" asset price dynamics or should it wait until the boom spontaneously turns into a crash and intervene afterwards to attenuate the fallout on the real economy? The standard "three equation" New Keynesian framework is inadequate to analyse this issue for the very simple reason that asset prices are not explicitly included in the model. There are two straightforward ways to take into account asset price dynamics in this framework. First of all, the objective function of the central bank - usually defined in terms of inflation and the output gap - could be "augmented" to take into account asset price inflation. Second, expected asset price inflation can affect the IS curve through a wealth effect. In this paper we follow a different route. In our model in fact, the expected asset price dynamics will be eventually incorporated into the NK Phillips curve. This is due to the assumption of a cost channel for monetary policy which is activated whenever monetary policy affects asset prices and dividends. In fact they determine the cost of external finance in the simple "equity only" financing model we consider, abstracting for simplicity from internal funds and the credit market.

Was Bernanke Right? Targeting Asset Prices may not be a Good Idea after all

Should the central bank prevent “excessive” asset price dynamics or should it wait until the boom spontaneously turns into a crash and intervene only afterwards? The debate over this issue goes back at least to the exchange between Bernanke-Gertler (BG) and Cecchetti but has not settled yet. In their 1999 paper BG claimed that price stability and financial stability are ‘highly complementary and mutually consistent objectives’ in a flexible inflation targeting regime which ‘dictates that central banks ... should not respond to changes in asset prices, except insofar as they signal changes in expected inflation.’ (BG, 1999, p.18). This conclusion is straightforward within the variant of the NK-DSGE framework used by BG in which asset inflation shows up as a factor ‘augmenting’ the IS curve. In the present paper, we pursue a different modelling strategy so that, in the end, asset price dynamics will be incorporated into the NK Phillips curve. In our context it is not true anymore that by focusing on inflation the central bank is also checking an asset price boom. We put ourselves, therefore, in the best position to obtain a significant stabilizing role for asset price targeting. It turns out, however, that inflation volatility is higher in the asset price targeting case. After all, therefore, targeting asset prices may not be a good idea.cost channel, asset prices, Taylor rules