HAL Paris Dauphine-PSL
Not a member yet
21932 research outputs found
Sort by
Certified to stay ? : long-run experimental evidence on land formalization and widows' tenure security in Benin
No full textIn settings where women's land rights are informal, the death of a husband can severely limit a widow's access to land and her ability to remain in her home?especially in the absence of a male heir. This paper examines whether large-scale land formalization programs can improve widows' land access. Using data from a random-ized controlled trial in rural Benin, the analysis finds that widows in villages with land formalization are more likely to stay in their homes four years after the program, withthe strongest effects among those without a male heir. The paper identifies two key mechanisms: enhanced community recognition of women's land rights and greaterdecision-making power over land resources. These findings highlight the potential of land formalization to strengthen women's tenure security and promote their long-termeconomic stability in similar settings
Structural Parameters for Steiner Orientation
No full textInternational audienceWe consider the Steiner Orientation problem, where we are given as input a mixed graph G = (V,E,A) and a set of k demand pairs (s_i,t_i), i ∈ [k]. The goal is to orient the undirected edges of G in a way that the resulting directed graph has a directed path from s_i to t_i for all i ∈ [k]. We adopt the point of view of structural parameterized complexity and investigate the complexity of Steiner Orientation for standard measures, such as treewidth. Our results indicate that Steiner Orientation is a surprisingly hard problem from this point of view. In particular, our main contributions are the following: 1) We show that Steiner Orientation is NP-complete on instances where the underlying graph has feedback vertex number 2, treewidth 2, pathwidth 3, and vertex integrity 6. 2) We present an XP algorithm parameterized by vertex cover number vc of complexity n^O(vc²). Furthermore, we show that this running time is essentially optimal by proving that a running time of n^o(vc²) would refute the ETH. 3) We consider parameterizations by the number of undirected or directed edges (|E| or |A|) and we observe that the trivial 2^|E| n^O(1)-time algorithm for the former parameter is optimal under the SETH. Complementing this, we show that the problem admits a 2^O(|A|) n^O(1)-time algorithm. In addition to the above, we consider the complexity of Steiner Orientation parameterized by tw+k (FPT), distance to clique (FPT), and vc+k (FPT with a polynomial kernel)
Hydrodynamic Limit of Multiscale Viscoelastic Models for Rigid Particle Suspensions
No full textInternational audienc
Fairness in Cooperative Multi-agent Multi-objective Reinforcement Learning using the Expected Scalarized Return
No full textInternational audienceFairness is essential for deploying artificial decision-making agents in the real world. Existing work in sequential decision-making ensures fairness among agents or objectives but struggles with real-world problems that are both multi-agent and multi-objective. Furthermore, research integrating fairness into Multi-Objective Reinforcement Learning (MORL) is focused on ensuring fairness over the objectives only on the average of several executions of a policy, which is achived by optimizing the policy's scalarized expected return (SER). To achieve fairness over objectives during each execution the expected scalarized return (ESR) of a policy needs to be optimized instead. This paper presents an argument on the necessity of using ESR in the context of fair multi-objective decision-making and proposes the first mono-policy algorithm able to learn efficient decentralized policies while ensuring fairness across objectives under ESR.</div
Des motivations aux résultats : explication de la construction identitaire difficile et persistante des contrôleurs de gestion
No full textThis thesis investigates the professional identity construction of management controllers, focusing on identity motives and outcomes using Ashforth and Schinoff’s (2016) framework. By analyzing 547 LinkedIn resumes and conducting 28 in-depth interviews, the study maps diverse career trajectories and explores how psychological needs such as uncertainty reduction and belonging, shape identity construction. It finds that identity motives are central to practice, cutting across contexts, and that local environments play a key role in validating role identities. The research challenges the idea of a single career model and emphasizes the importance of time and context in understanding controllers’ evolving professional identities.Cette thèse explore la construction de l'identité professionnelle des contrôleurs de gestion, en s'appuyant sur le cadre d’Ashforth et Schinoff (2016), en mettant l’accent sur les motivations identitaires et leurs résultats. À partir de 547 CV LinkedIn et de 28 entretiens, elle identifie six trajectoires de carrière distinctes, remettant en question l’idée d’un modèle unique. Les motivations psychologiques, comme la réduction de l’incertitude et le besoin d’appartenance, influencent fortement les pratiques professionnelles. Le contexte local est essentiel pour valider les identités, malgré la fluidité du rôle. L’étude souligne l'importance du temps et du contexte dans cette évolution
Inégalités doctorales entre les Nords et les Suds : Revue de littérature, pp. 183–201
No full textInternational audienceThis chapter explores Global North-South doctoral inequalities, focusing specifically on the challenges faced by African PhD students. Through an initial exploration of the literature, we address the structural inequalities present in international research practices and their historical roots, highlighting their repercussions on doctoral conditions in the Global South. We then examine inequalities in terms of access, funding, working and study conditions, as well as obstacles related to gender and international mobility. Our analysis reveals a complex overview of structural, socio-economic, and institutional inequalities exacerbating the challenges for African PhD students. By shedding light on the specific obstacles to access and success in doctoral studies on the African continent, this article contributes to the debate on the need for more equitable international cooperation and the strengthening of institutional and financial capacities to promote more inclusive and fair science.Ce chapitre explore les inégalités doctorales Nords-Suds, en se concentrant spécifiquement sur les défis rencontrés par les doctorants africains. À travers une première exploration de la littérature, nous abordons les inégalités structurelles présentes dans les pratiques de recherche internationales et leurs racines historiques, mettant en évidence leurs répercussions sur les conditions doctorales aux Suds. Nous examinons ensuite les inégalités en termes d’accès, de financement, de conditions de travail et d’études, ainsi que les obstacles liés au genre et à la mobilité internationale. Notre analyse révèle un panorama complexe d’inégalités structurelles, socio-économiques et institutionnelles exacerbant les défis pour les doctorants des Afriques. En mettant en lumière les obstacles spécifiques à l’accès et à la réussite des études doctorales sur le continent africain, cet article contribue au débat sur la nécessité d’une coopération internationale plus équitable et d’un renforcement des capacités institutionnelles et financières pour promouvoir une science plus inclusive et juste
Multitime fields and hard rod scaling limits
No full textA Poisson line process is a random set of straight lines contained in the plane, as the image of the map , for each point of a Poisson process in the space-velocity plane. By associating a step with each line of the process, a random surface called multitime walk field is obtained. The diffusive rescaling of the surface converges to the multitime Brownian motion, a classical Gaussian field also called Lévy-Chentsov field. A cut of the multitime fields with a perpendicular plane, reveals a one dimensional continuous time random walk and a Brownian motion, respectively. A hard rod is an interval contained in that travels ballistically until it collides with another hard rod, at which point they interchange positions. By associating each line with the ballistic displacement of a hard rod and associating surface steps with hard rod jumps, we obtain the hydrodynamic limits of the hard rods in the Euler and diffusive scalings. The main tools are law of large numbers and central limit theorems for Poisson processes. When rod sizes are zero we have an ideal gas dynamics. We describe the relation between ideal gas and hard-rod invariant measures
Mean field games with common noise and degenerate idiosyncratic noise
No full textInternational audienc
Uniform Value and Decidability in Ergodic Blind Stochastic Games
No full textWe study a class of two-player zero-sum stochastic games known as \textit{blind stochastic games}, where players neither observe the state nor receive any information about it during the game. A central concept for analyzing long-duration stochastic games is the \textit{uniform value}. A game has a uniform value if for every , Player 1 (resp., Player 2) has a strategy such that, for all sufficiently large , his average payoff over stages is at least (resp., at most ). Prior work has shown that the uniform value may not exist in general blind stochastic games. To address this, we introduce a subclass called \textit{ergodic blind stochastic games}, defined by imposing an ergodicity condition on the state transitions. For this subclass, we prove the existence of the uniform value and provide an algorithm to approximate it, establishing the \textit{decidability} of the approximation problem. Notably, this decidability result is novel even in the single-player setting of Partially Observable Markov Decision Processes (POMDPs). Furthermore, we show that no algorithm can compute the uniform value exactly, emphasizing the tightness of our result. Finally, we establish that the uniform value is independent of the initial belief