La Création D'activité: Prise D'autonomie Et Médiation Entre Acteurs

Résumé Depuis le début des années 1980 des initiatives d'accompagnement et de financement de petites activités économiques à destination des personnes en situation d'exclusion économique et sociale se sont développées dans les pays du Nord. Relevant du champ du « tiers secteur >>, et en particulier de l'économie solidaire contemporaine, elles visent à la fois à répondre à des besoins insatisfaits et à introduire le principe d'un droit à l'initiative économique. Leur conception des inégalités économique et sociale, axée sur l'approche par les capabilités d'Amartya Sen, permet de comprendre leur mode d'organisation combinant une double dimension financière et sociale.     

Multidimensional strong large deviation results

We establish strong large deviation results for an arbitrary sequence of random vectors under some assumptions on the normalized cumulant generating function. In other words, we give asymptotic approximations for a multivariate tail probability of the same kind as the one obtained by Bahadur and Rao (Ann Math Stat 31:1015–1027, 1960) for the sample mean (in the one-dimensional case). The proof of our results follows the same lines as in Chaganty and Sethuraman (J Stat Plan Inference, 55:265–280, 1996). We also present three statistical applications to illustrate our results, the first one dealing with a vector of independent sample variances, the second one with a Gaussian multiple linear regression model and the third one with the multivariate Nadaraya–Watson estimator. Some numerical results are also presented for the first two applications.     

VaR and ES for linear portfolios with mixture of generalized Laplace distributions risk factors

In this paper, we propose an explicit estimation of Value-at-Risk (VaR) and Expected Shortfall (ES) for linear portfolios when the risk factors change with a convex mixture of generalized Laplace distributions (M-GLD). We introduce the dynamics Delta-GLD-VaR, Delta-GLD-ES, Delta-MGLD-VaR and Delta-MGLD-ES, by using conditional correlation multivariate GARCH. The generalized Laplace distribution impose less restrictive assumptions during estimation that should improve the precision of the VaR and ES through the varying shape and fat tails of the risk factors in relation with the historical sample data. We also suggested some areas of application to measure price risk in agriculture, risk management and financial portfolio optimization.     

Adoption and impact of improved maize varieties on maize yields: Evidence from central Cameroon

This study uses both the endogenous switching regression and propensity score matching models to analyze the adoption and impact of improved maize varieties on maize yields in central Cameroon. The results show that (i) education level, agricultural training, proximity to an Institute of Agricultural Research for Development branch and farmers’ perceptions of yield and risk of improved maize varieties significantly affect the adoption of improved maize varieties and (ii) the adoption of improved maize varieties enhances maize yields. Therefore, policies designed to stimulate adoption of improved maize varieties should be promoted. Improvement of access to school and agricultural training may serve as good strategies for promoting the adoption of improved maize varieties in Cameroon.     

Exchange Market Pressure in the Central African Economic and Monetary Community (CAEMC) Area: Empirical Assessment of the Macroeconomic Determinants

ABSTRACT

The current empirical study contributes to the literature on the exchange market pressure. First we construct as proposed by Eichengreen, Rose, and Wyplosz [1996. Contagious currency crises: First tests. The Scandinavian Journal of Economics, 98 (4), 463–484], a continuous measure of EMP for the CAEMC franc zone, using quarterly data from 1985Q1 to 2012Q2. We then address the main macroeconomic determinants of this EMP.

We find that our main measure for EMP as well as two alternative measures of this index captures quite well episodes of crises of the CFA (XAF) currency. During the period of study, the common currency of the CAEMC countries experienced about four speculative attacks, with the one in 1993 ending with the devaluation of that currency in January 1994. The other attacks were warded off through reserves losses, as it is clear that the currency peg was maintained principally through changes in reserves. We also find that the GDP growth, the trade balance and the international oil price are the main contributors of EMP and therefore the most significant predictors of currency crises in the CAEMC area.     

The Paris financial market in the nineteenth century: complementarities and competition in microstructures1

This article sets out to explain why the Paris Bourse was highly successful in the nineteenth century in spite of the supposedly inefficient monopoly of the official market, the Parquet. The literature argues that the official monopoly was sidelined by a free, innovative market known as the Coulisse, but it fails to explain how the Coulisse emerged despite the monopoly and how the two markets persisted alongside each other during the entire century. We provide a detailed history of how these two markets emerged and interacted. The Parquet increasingly developed as a high‐end market, providing security, transparency, and effective settlement‐delivery to unsophisticated investors trading on the spot market. The Coulisse provided liquidity, immediacy, and opacity to professional investors trading mostly forward. In line with recent theoretical developments, we argue that the juxtaposition of heterogeneous organizations had important virtues for market participants, since it allowed the exchanges to specialize in different investors and services and made the exchanges complementary to each other. We demonstrate our claim by looking at both the formal rules and the actual functioning of the Parquet, drawing on its archives which we have recently classified.     

Calibrating the exponential Ornstein–Uhlenbeck multiscale stochastic volatility model

This paper demonstrates a tractable and efficient way of calibrating a multiscale exponential Ornstein–Uhlenbeck stochastic volatility model including a correlation between the asset return and its volatility. As opposed to many contributions where this correlation is assumed to be null, this framework allows one to describe the leverage effect widely observed in equity markets. The resulting model is non-exponential and driven by a degenerate noise, thus requiring a high level of care in designing the estimation algorithm. The way this difficulty is overcome provides guidelines concerning the development of an estimation algorithm in a non-standard framework. The authors propose using a block-type expectation maximization algorithm along with particle smoothing. This method results in an accurate calibration process able to identify up to three timescale factors. Furthermore, we introduce an intuitive heuristic which can be used to choose the number of factors.     

On the performance of voting systems in spatial voting simulations

We study the performance of voting systems in terms of minimizing the overall social disutility of making a collective choice in an univariate voting space with ideological voting and perfect information. In order to obtain a distribution of the performance indicator for each of the 12 systems chosen for this study—Baldwin’s Method, Black’s Method, The Borda Count, Bucklin’s Grand Junction System, Coombs’ Method, Dodgson’s System, Instant Run-Off Voting, Plurality, Simpson’s MinMax, Tideman’s Ranked Pairs, Schulze’s Beatpath Method, and Two-Round Majority—we simulate elections using an Agent-Based Computational approach under several different distributions for voters and candidates positioning, with up to 15 available candidates. At each iteration, voters generate complete and strict ordinal utility functions over the set of available candidates, based on which each voting system computes a winner. We define the performance of a system in terms of its capability of choosing among the available candidates the one that minimizes aggregate voter disutility. As expected, the results show an overall dominance of Condorcet completion methods over the traditional and more widely used voting systems, regardless of the distributions of voter and candidate positions.