A three-phased local search approach for the clique partitioning problem

This paper presents a three-phased local search heuristic CPP-P\(^{3}\) for solving the Clique Partitioning Problem (CPP). CPP-P\(^{3}\) iterates a descent search, an exploration search and a directed perturbation. We also define the Top Move of a vertex, in order to build a restricted and focused neighborhood. The exploration search is ensured by a tabu procedure, while the directed perturbation uses a GRASP-like method. To assess the performance of the proposed approach, we carry out extensive experiments on benchmark instances of the literature as well as newly generated instances. We demonstrate the effectiveness of our approach with respect to the current best performing algorithms both in terms of solution quality and computation efficiency. We present improved best solutions for a number of benchmark instances. Additional analyses are shown to highlight the critical role of the Top Move-based neighborhood for the performance of our algorithm and the relation between instance hardness and algorithm behavior.     

A Cause-of-Death Decomposition of Young Adult Excess Mortality

We propose a method to decompose the young adult mortality hump by cause of death. This method is based on a flexible shape decomposition of mortality rates that separates cause-of-death contributions to the hump from senescent mortality. We apply the method to U.S. males and females from 1959 to 2015. Results show divergence between time trends of hump and observed deaths, both for all-cause and cause-specific mortality. The study of the hump shape reveals age, period, and cohort effects, suggesting that it is formed by a complex combination of different forces of biological and socioeconomic nature. Male and female humps share some traits in all-cause shape and trend, but they also differ by their overall magnitude and cause-specific contributions. Notably, among males, the contributions of traffic and other accidents were progressively replaced by those of suicides, homicides, and poisonings; among females, traffic accidents remained the major contributor to the hump.     

A post-apartheid paradigm? a view from the outside

The South African student movements of 2015 and 2016 have critically recalled the question: how to dismantle the thinking inherited from apartheid? More than twenty years after the fall of the racist regime, this question still haunt South African humanities. While the term “post-apartheid” might have addressed this urgency and even crystallized an intellectual ambition, it’s multiple and sometimes contradictory meanings have made it hard to establish a paradigm. The authors of this special section have sought to interrogate the use and abuse of the concept in the literature of their respective disciplines, keeping in mind that, whatever its polysemy, the term has become a reference point for the humanities worldwide, as untranslatable as it is inescapable.     

L'émergence d'un nouveau mode de gouvernement local des réseaux en Allemagne. Une ville moyenne et son Stadtwerk face au processus de libéralisation

On the basis of a long-term study of a Stadtwerk located in a middle-sized town, questions are raised about changes in the local governance of networks in Germany. Neoliberal reforms and the budgetary crisis at the communal level are powerful factors driving change, which, for municipal authorities, reflects not a loss of power as such but a transformation of the relations it used to have with its Stadtwerk. A new type of interaction is emerging; it is much more formalized and based on standing relatively clear of politics. Municipal authorities are taking back the role of strategic and financial leadership that had been downplayed during the previous period characterized by a monopoly and communal prosperity.     

On generalized variance of product of powered components and multiple stable Tweedie models

A flexible family of multivariate models, named multiple stable Tweedie (MST) models, is introduced and produces generalized variance functions which are products of powered components of the mean. These MST models are built from a fixed univariate stable Tweedie variable having a positive value domain, and the remaining random variables given the fixed one are also real independent Tweedie variables, with the same dispersion parameter equal to the fixed component. In this huge family of MST models, generalized variance estimators are explicitly pointed out by maximum likelihood method and, moreover, computably presented for the uniform minimum variance and unbiased approach. The second estimator is brought from modified Lévy measures of MST which lead to some solutions of particular Monge–Ampère equations.