205,986 research outputs found
An investigation into hybrid power trains for vehicles with regenerative braking
Imperial Users onl
Strategy-proof allocation mechanisms for economies with public goods
This paper provides a characterization of the class of incentive compatible (i.e., strategy-proof) allocation mechanisms for decision problems associated with classical economic environments. It is shown that when at least one public good is provided, then only dictatorial allocation mechanisms are incentive compatible. Dictatorial mechanisms are very unsatisfactory, as any conflict of interest is always resolved in favor of a single individual (the dictator). This result reveals a basic incompatibility between incentive compatibility and any other desirable property (e.g., any kind of efficiency, fairness, etc.) of an allocation mechanism. In particular, incentive compatible allocation mechanisms typically produce inefficient outcomes
Strategy-proof allocation mechanisms for pure public goods economies when preferences are monotonic
A fundamental problem in public finance is that of allocating a␣given budget to financing the provision of public goods (education, transportation, police, etc.). In this paper it is established that when␣admissible preferences are those representable by continuous and increasing utility functions, then strategy-proof allocation mechanisms whose (undominated) range contains three or more outcomes are dictatorial on the set of profiles of strictly increasing utility functions, a dense subset of the domain in the topologies commonly used in this context. If admissible utility functions are further restricted to be strictly increasing, or if mechanisms are required to be non-wasteful, then strategy-profness leads to (full) dictatorship.Publicad
The flux suppression at the highest energies
Almost half a century ago, Greisen, Zatsepin and Kuz'min (GZK) predicted a
"cosmologically meaningful termination" of the spectrum of cosmic rays at
energies around eV due to their interaction with the cosmic microwave
background, as they propagate from distant extragalactic sources. A suppression
of the flux above eV is now confirmed. We argue that current
data are insufficient to conclude whether the observed feature is due to energy
loss during propagation, or else to the fact that the astrophysical
accelerators reach their limit, or indeed to a combination of both source
properties and propagation effects. We discuss the dependence of the spectral
steepening upon the cosmic-ray composition, source properties, and intervening
magnetic fields, and speculate on the additional information that may be
necessary to reach unambiguous conclusions about the origin of the flux
suppression and of the mechanisms behind the acceleration of cosmic rays up to
the highest observed energies.Comment: Invited review prepared for Comptes Rendus Physique (2014), in pres
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