4,033 research outputs found
Pooling or sampling: Collective dynamics for electrical flow estimation
The computation of electrical flows is a crucial primitive for many recently proposed optimization algorithms on weighted networks. While typically implemented as a centralized subroutine, the ability to perform this task in a fully decentralized way is implicit in a number of biological systems. Thus, a natural question is whether this task can provably be accomplished in an efficient way by a network of agents executing a simple protocol. We provide a positive answer, proposing two distributed approaches to electrical flow computation on a weighted network: a deterministic process mimicking Jacobi's iterative method for solving linear systems, and a randomized token diffusion process, based on revisiting a classical random walk process on a graph with an absorbing node. We show that both processes converge to a solution of Kirchhoff's node potential equations, derive bounds on their convergence rates in terms of the weights of the network, and analyze their time and message complexity
Top mass determination, Higgs inflation, and vacuum stability
The possibility that new physics beyond the Standard Model (SM) appears only
at the Planck scale is often considered. However, it is usually argued
that new physics interactions at do not affect the SM stability phase
diagram, so the latter is obtained neglecting these terms. According to this
diagram, for the current experimental values of the top and Higgs masses, our
universe lives in a metastable state (with very long lifetime), near the edge
of stability. Contrary to these expectations, however, we show that the
stability phase diagram strongly depends on new physics and that, despite
claims to the contrary, a more precise determination of the top (as well as of
the Higgs) mass will not allow to discriminate between stability, metastability
or criticality of the electroweak vacuum. At the same time, we show that the
conditions needed for the realization of Higgs inflation scenarios (all
obtained neglecting new physics) are too sensitive to the presence of new
interactions at . Therefore, Higgs inflation scenarios require very severe
fine tunings that cast serious doubts on these models.Comment: 20 pages, 10 figure
Impact of Gravity on Vacuum Stability
In a pioneering paper on the role of gravity on false vacuum decay, Coleman
and De Luccia showed that a strong gravitational field can stabilize the false
vacuum, suppressing the formation of true vacuum bubbles. This result is
obtained for the case when the energy density difference between the two vacua
is small, the so called thin wall regime, but is considered of more general
validity. Here we show that when this condition does not hold, however, {\it a
strong gravitational field (Planckian physics) does not necessarily induce a
total suppression of true vacuum bubble nucleation}. Contrary to common
expectations then, gravitational physics at the Planck scale {\it does not
stabilize the false vacuum}. These results are of crucial importance for the
stability analysis of the electroweak vacuum and for searches of new physics
beyond the Standard Model.Comment: 6 pages, 4 figure
Server resource dimensioning and routing of service function chain in NFV network architectures
The Network Function Virtualization (NFV) technology aims at virtualizing the network service with the execution of the single service components in Virtual Machines activated on Commercial-off-the-shelf (COTS) servers. Any service is represented by the Service Function Chain (SFC) that is a set of VNFs to be executed according to a given order. The running of VNFs needs the instantiation of VNF instances (VNFI) that in general are software components executed on Virtual Machines. In this paper we cope with the routing and resource dimensioning problem in NFV architectures. We formulate the optimization problem and due to its NP-hard complexity, heuristics are proposed for both cases of offline and online traffic demand. We show how the heuristics works correctly by guaranteeing a uniform occupancy of the server processing capacity and the network link bandwidth. A consolidation algorithm for the power consumption minimization is also proposed. The application of the consolidation algorithm allows for a high power consumption saving that however is to be paid with an increase in SFC blocking probability
Can the class cleavage still explain support for left-wing parties?
The electoral strength of left-wing parties has traditionally been linked to the size and nature of a country’s working class and the existence of strong organisations such as trade unions. But are these ‘class cleavage’ factors still important in today’s politics? Drawing on a new study, Vincenzo Emanuele finds that while the characteristics of the working class are still a significant predictor of votes for the left, the importance of the organisational dimension has largely disappeared over the last two decades
Dataset of Electoral Volatility and its internal components in Western Europe (1945-2015)
This dataset provides data on electoral volatility and its internal components in parliamentary elections (lower house) in 20 countries of Western Europe for the period 1945-2015. It covers the entire universe of Western European elections held after World War II under democratic regimes. Data for Greece, Portugal and Spain have been collected after their democratizations in the 1970s. Altogether, a total of 347 elections (or, more precisely, electoral periods) are included.
This dataset will be regularly updated so as to include latest elections.
How to cite this dataset?
Emanuele, V. (2015), Dataset of Electoral Volatility and its internal components in Western Europe (1945-2015), Rome: Italian Center for Electoral Studies, http://dx.doi.org/10.7802/111
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