Extrapolation methods use the last few iterates of an optimization algorithm to produce a better estimate of the optimum. They were shown to achieve optimal convergence rates in a deterministic setting using simple gradient iterates. Here, we study extrapolation methods in a stochastic setting, where the iterates are produced by either a simple or an accelerated stochastic gradient algorithm. W...

We study local optima of the Hamiltonian of the Sherrington-Kirkpatrick model. We compute the exponent of the expected number of local optima and determine the “typical” value of the Hamiltonian. *Supported by NSERC Discovery Grant 341845. †Supported by the Natural Sciences and Engineering Research Council (NSERC) of Canada. ‡Supported by the SpanishMinistry of Economy and Competitiveness, Gran...

The resource limited nature of WSNs require that protocols implemented on these networks be energy-efficient, scalable and distributed. This paper presents an analysis of a novel combined routing and MAC protocol. The protocol achieves energy-efficiency by minimizing signaling overhead through state-less routing decisions that are made at the receiver rather than at the sender. The protocol dep...

Iran is one f the biggest oil producer and exporter of the world. Due to the special administrative and constitutional structure of the country, i.e. economic, social and political reasons, the government budget and revenues depend heavily on oil exports. The aim of this article is to suggest a theoretical proposal on the optimum level of non-oil exports such that it will clear up the idea of e...

Deep generative models such as deep latent Gaussian models (DLGMs) are powerful and popular density estimators. However, they have been applied almost exclusively to dense data such as images; DLGMs are rarely applied to sparse, high-dimensional integer data such as word counts or product ratings. One reason is that the standard training procedures find poor local optima when applied to such da...

The majority of the literature on the psychology of gains and losses suggests that losses lead to an avoidance response. Several studies, however, have shown that losses can also lead to an approach response, whereby an option is selected more often when it produces losses. In five studies we examine the boundary conditions for these contradictory approach and avoidance effects. The results sho...

This paper presents a simple and locally optimal test for Zipf’s law. Its use is illustrated in the case of the largest US metropolitan areas. An objection to the general relevance of that law is also presented.  2000 Elsevier Science S.A. All rights reserved.

Escaping local optima and crossing fitness valleys to reach higher-fitness regions of a fitness landscape is a ubiquitous concept in much writing on evolutionary difficulty. The Baldwin effect, an interaction between non-heritable lifetime plasticity (e.g. learning) and evolution, has been shown to be able to guide evolutionary change and ‘smooth out’ abrupt fitness changes in fitness landscape...

Sectoral labor supply shortage is a cause of concern in many OECD countries and has raised support for immigration as a potential remedy. In this paper, we derive a general equilibrium model with overlapping generations, where natives require a compensating wage differential for working in one sector rather than in another. We identify price and wage effects of immigration on three different gr...