Single approximation for the biobjective Max TSP

We mainly study the Max TSP with two objective functions. We propose an algorithm which returns a single Hamiltonian cycle with performance guarantee on both objectives. The algorithm is analyzed in three cases. When both (respectively, at least one) objective function(s) fulfill(s) the triangle inequality, the approximation ratio is View the MathML source512−ε≈0.41 (respectively, View the MathML source38−ε). When the triangle inequality is not assumed on any objective function, the algorithm is View the MathML source1+2214−ε≈0.27-approximate.nonouirechercheInternationa

Consumption Growth and Spatial Poverty Traps: An Analysis of the Effect of Social Services and Community Infrastructures on Living Standards in Rural Peru

Why are there areas with persistenly low levels of income or consumption? This could result from the concentration of households with a low capital endowment or from variations in households’ environment. Peru is a country with a very much fragmented topography and climate, that combines dry deserts, high mountains and rain forest. One important question is to assess the weight of the geographic endowment in the growth process. If differences in geographic endowment matter more than those in households’ characteristics, then encouraging migration to better endowed regions might be a good development policy whereas, in the opposite, it might be better to invest in households’ capital. Of course several factors, either geographic or not, can combine to explain persistent poverty in a given area. In this chapter we test the effect of local geographic endowment of capital on household growth in living standards in rural Peru, using a four years unbalanced panel data set. Our theoretical model of household consumption growth allows for the effect of community variables to modify the returns to augmented capital in the household production function. Three different sources of data are used: the ENAHO 1997-2000 households surveys, the population census of 1993 and the district infrastructure census of 1997. Altogether the addition of these different data sources makes an unusually rich data set, at least when considered with developing country standards. As in Jalan and Ravallion (2002), we use a quasi-differencing method to identify the impact of locally determined geographic and socioeconomic variables, while removing unobserved household and community level fixed effects. GMM are then used to estimate the model parameters. Several significant interesting results appear, showing that private consumption growth depends on local geographic variables, but more on local endowments of private and public assets than on pure geographic characteristics. This suggests to combine policies focused on private and public asset endowments that will reinforce local positive externalities, with infrastructure investments that will help poor households to take advantage of growth opportunities, offered by more dynamic markets across local communities.nonouirechercheInternationa

Comment les différences de parcours professionnels contribuent - elles aux écarts de santé entre femmes et hommes ?

nonnonnon-rechercheNationa

Propagation of chaos for the spatially homogeneous Landau equation for maxwellian molecules

We prove a quantitative propagation of chaos and entropic chaos, uniformly in time, for the spatially homogeneous Landau equation in the case of Maxwellian molecules. We improve the results of Fontbona, Guérin and Méléard [9] and Fournier [10] where the propagation of chaos is proved for finite time. Moreover, we prove a quantitative estimate on the rate of convergence to equilibrium uniformly in the number of particles.nonnonouirechercheInternationa

Entre permanence et (r)évolution : les finalités sociétales de la recherche française en marketing

Cet article explore les finalités poursuivies par la recherche française en marketing. Une analyse scientométrique des communications de cinq Congrès de l'AFM révèle la permanence d'un puissant paradigme managérial et le développement récent de travaux plus sociétaux. Ces résultats sont discutés dans une perspective historique et critique.This article explores the purposes pursued by the French research in marketing. A scientometric analysis of four AFM Congresses communications reveals the permanence of a powerful managerial paradigm and the recent development of more societal questions. These results are discussed in a historical and critical perspective.nonouirechercheNationa

Women's empowerment across the life cycle and generations: Evidence from Sub-Saharan Africa

L'autonomisation des femmes, leur "empowerment", évolue-t-elle tout au long de leur cycle de vie ?S'est-elle renforcée au fil des générations ? A partir de données issues des Enquêtes Démographiques et de Santé portant sur un échantillon de 191 000 femmes adultes, nous estimons les effets d'âge, de période et de cohorte sur le refus de la violence conjugale, pris comme mesure de l'empowerment.Nous construisons un pseudo-panel en mobilisant des données de plusieurs vagues d'enquêtes consécutives menées dans cinq pays d'Afrique Sub-Saharienne au cours des années 2000. Lesestimations montrent qu'en terme de cycle de vie, plus les femmes vieillissent, moins elles considèrentla violence conjugale comme justifiable. Parallèlement, en terme de générations, les femmes des plus jeunes cohortes ont une moindre probabilité d'accepter la violence conjugale, à niveau d'éducation donné. Dans la décomposition Age-Période-Cohorte, les effets de l'âge et de la période d'enquête se révèlent être les plus importants. On montre également que les effets de l'âge sont en partie expliquéspar les changements de la situation des femmes sur le marché du travail, la composition de leur ménage et leur rôle de parent.Does female empowerment evolve over the life cycle, and has it changed across generations? We use data from the Demographic and Health Surveys covering a sample of about 191,000 adult women to evaluate the age, period and cohort effect regarding individual attitudes to marital violence. Pseudopaneldata are constructed from repeated cross-sections from five African countries in the 2000s. The estimates show that, over the life cycle, women tend to think that marital violence is less and less justifiable, and that younger cohorts are less likely than older cohorts to view marital violence as justifiable, even controlling for education. In the full age-period-cohort decomposition, the age andperiod effects are the most important. Age effects are driven by changes in labor-force status, household composition and parenthood.nonnonouirechercheInternationa

Les contrats des collectivités territoriales et le droit de la concurrence

nonouinon-rechercheNationa

Social Choice Theory

Social choice theory is the formal study of collective decision-making. Its modern version was initiated by both Arrow and Black and is concerned with the construction of a social preference out of individual preferences.nonouirechercheInternationa

Protection of transport infrastructures against major accidents in land use planning policies. A decision support approach

Users of transport infrastructures nearby hazardous plants may represent important populations potentially impacted by a major accident. Toulouse catastrophe in 2011 has been an illustrative example as it strongly impacted highway users. Therefore, transport infrastructure users (Roads and railways mainly) represent a population to be protected within a land use planning policy as it is the case for inhabitants.Accordingly, this paper presents a decision support approach aiming to help local stakeholders identifying the most cost effective measures to protect transport infrastructures from major accidental consequences. The suggested approach takes in account both technical and participatory constraints with the aim of offering an equal chance to all involved stakeholders to understand the issues under discussion and formulate opinions and values.After a description of the French regulatory context, the major technical difficulties related to transport infrastructures protection will be described before introducing the main technical choices adopted by the team. Finally, a decision support procedure is described and a real case study presented.This work is strongly embedded in the French regulatory context. However, we believe the decision support structure as fully adaptable to other regulatory contexts.nonouirechercheInternationa

Forward Curve Risk Factors Analysis in the UK Real Estate Market

This paper empirically investigates the risk factors of the property swap prices using 4 years of price data relative to the UK Investment Property Databank (IPD) Total Return All Property Swap. The implied forward rates are analyzed with a first difference model to determine its main components. Regarding the risk free rate, the traditional sport-forward relation does not hold for property derivatives. The impact of the risk free rate on forward rates appears as being complex and made of different effects; it varies according to time and maturities. Derivatives prices take into account the smoothing effect of the underlying index and REITs stocks are also relevant to explain these prices. The informational content of the swap is important. The impact of the REITs and of the smoothing decreases with maturities. The risk factor structure obtained is more complex than found in many other studies relative to commodities, securities or bonds. Possible reasons for this phenomenon are discussed.nonouirechercheInternationa