6,745 research outputs found

    Labor market regimes and monetary policy

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    In this paper we propose straightforward extensions of multi-union, monopolistic competition models appearing in the recent literature on the macroeconomic effects of monetary policy. We extend these models from the Stackelberg equilibrium to the Nash equilibrium under variations in labor market regime in order to evaluate propositions about non-neutrality of monetary policy.policy game monetary policy neutrality trade union monopolistic competition

    Meeting in a Polygon by Anonymous Oblivious Robots

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    The Meeting problem for k≄2k\geq 2 searchers in a polygon PP (possibly with holes) consists in making the searchers move within PP, according to a distributed algorithm, in such a way that at least two of them eventually come to see each other, regardless of their initial positions. The polygon is initially unknown to the searchers, and its edges obstruct both movement and vision. Depending on the shape of PP, we minimize the number of searchers kk for which the Meeting problem is solvable. Specifically, if PP has a rotational symmetry of order σ\sigma (where σ=1\sigma=1 corresponds to no rotational symmetry), we prove that k=σ+1k=\sigma+1 searchers are sufficient, and the bound is tight. Furthermore, we give an improved algorithm that optimally solves the Meeting problem with k=2k=2 searchers in all polygons whose barycenter is not in a hole (which includes the polygons with no holes). Our algorithms can be implemented in a variety of standard models of mobile robots operating in Look-Compute-Move cycles. For instance, if the searchers have memory but are anonymous, asynchronous, and have no agreement on a coordinate system or a notion of clockwise direction, then our algorithms work even if the initial memory contents of the searchers are arbitrary and possibly misleading. Moreover, oblivious searchers can execute our algorithms as well, encoding information by carefully positioning themselves within the polygon. This code is computable with basic arithmetic operations, and each searcher can geometrically construct its own destination point at each cycle using only a compass. We stress that such memoryless searchers may be located anywhere in the polygon when the execution begins, and hence the information they initially encode is arbitrary. Our algorithms use a self-stabilizing map construction subroutine which is of independent interest.Comment: 37 pages, 9 figure

    Crisi e rimobilitazione: gli italiani, la politica, i partiti nelle indagini campionarie del CISE (2011-2012)

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    Nella primavera 2012, pochi mesi dopo l\u2019insediamento del governo Monti, i partiti italiani toccavano il punto pi\uf9 basso della loro presa sull\u2019opinione pubblica italiana: altissime percentuali di astenuti e indecisi, con un elettorato demotivato da un\u2019offerta politica ancora incerta (anche a causa della difficile convivenza con un governo tecnico) e quindi incapace di strategie innovative. Tuttavia, \ue8 forse vero che la politica ha orrore del vuoto: l\u2019imminenza delle elezioni amministrative (del maggio 2012) e soprattutto l\u2019ingresso nell\u2019ultimo anno prima delle elezioni politiche segnano una ripresa dell\u2019iniziativa politica, sia da parte dei partiti esistenti che da parte di nuovi attori politici. Il primo a muoversi \ue8 il Movimento 5 Stelle, con un\u2019aggressiva strategia per le elezioni amministrative, in cui registrer\ue0 un grande successo. Ma in secondo luogo \ue8 il centrosinistra a gettarsi in una impegnativa e rischiosa strategia politica basata sulle primarie, che otterr\ue0 tuttavia il grande risultato di una significativa rimobilitazione del proprio elettorato. Tutte queste tendenze sono state puntualmente registrate dalla serie di indagini demoscopiche Osservatorio Politico CISE, condotte ogni sei mesi a partire dalla primavera 2011. I risultati di queste indagini, gi\ue0 pubblicati sul sito web Cise nel corso del 2012, sono raccolti oggi in questo secondo Dossier CISE. Una riflessione sul clima di opinione pubblica che conduce alle elezioni politiche del 2013, che vuole fornire dati utili per interpretare le ultime fasi della campagna elettorale e per inquadrare l\u2019ormai imminente risultato delle elezioni

    TuringMobile: A Turing Machine of Oblivious Mobile Robots with Limited Visibility and Its Applications

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    In this paper we investigate the computational power of a set of mobile robots with limited visibility. At each iteration, a robot takes a snapshot of its surroundings, uses the snapshot to compute a destination point, and it moves toward its destination. Each robot is punctiform and memoryless, it operates in R^m, it has a local reference system independent of the other robots\u27 ones, and is activated asynchronously by an adversarial scheduler. Moreover, the robots are non-rigid, in that they may be stopped by the scheduler at each move before reaching their destination (but are guaranteed to travel at least a fixed unknown distance before being stopped). We show that despite these strong limitations, it is possible to arrange 3m+3k of these weak entities in R^m to simulate the behavior of a stronger robot that is rigid (i.e., it always reaches its destination) and is endowed with k registers of persistent memory, each of which can store a real number. We call this arrangement a TuringMobile. In its simplest form, a TuringMobile consisting of only three robots can travel in the plane and store and update a single real number. We also prove that this task is impossible with fewer than three robots. Among the applications of the TuringMobile, we focused on Near-Gathering (all robots have to gather in a small-enough disk) and Pattern Formation (of which Gathering is a special case) with limited visibility. Interestingly, our investigation implies that both problems are solvable in Euclidean spaces of any dimension, even if the visibility graph of the robots is initially disconnected, provided that a small amount of these robots are arranged to form a TuringMobile. In the special case of the plane, a basic TuringMobile of only three robots is sufficient

    Attosecond Streaking in the Water Window: A New Regime of Attosecond Pulse Characterization

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    We report on the first streaking measurement of water-window attosecond pulses generated via high harmonic generation, driven by sub-2-cycle, CEP-stable, 1850 nm laser pulses. Both the central photon energy and the energy bandwidth far exceed what has been demonstrated thus far, warranting the investigation of the attosecond streaking technique for the soft X-ray regime and the limits of the FROGCRAB retrieval algorithm under such conditions. We also discuss the problem of attochirp compensation and issues regarding much lower photo-ionization cross sections compared with the XUV in addition to the fact that several shells of target gases are accessed simultaneously. Based on our investigation, we caution that the vastly different conditions in the soft X-ray regime warrant a diligent examination of the fidelity of the measurement and the retrieval procedure.Comment: 14 Pages, 12 figure
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