HAL Paris Dauphine-PSL
Not a member yet
21932 research outputs found
Sort by
Existence, Computation and Efficiency of Nash Stable Outcomes in Hedonic Skill Games
No full textInternational audienceThis article deals with hedonic skill games, a non-transferable utility counterpart of coalitional skill games which model collaboration among entities through the abstract notions of tasks and the skills required to complete them. In the weighted tasks setting, we show that deciding whether an instance of the game admits a Nash stable outcome is NP-complete. We then characterize the instances admitting a Nash stable outcome. This characterization relies on the fact that every agent holds (resp., every task requires) either a single skill or more than one skill. For these instances, the complexity of computing a Nash stable outcome is determined, together with the possibility that natural dynamics converge to a Nash stable outcome from any initial configuration. Our study is completed with a thorough analysis of the price of anarchy of instances always admitting a Nash stable outcome
ILP for optimal multi-battery management systems on SPOT and curtailment electricity markets with large temporal horizon
No full textNational audienc
"Learning in the flow of work", un concept à l'épreuve de la réalité du travail
No full textInternational audienceDans un monde post-Covid-19, le marché du travail évolue sous l’effet de transformations structurelles qui font évoluer les relations entre les managers et les collaborateurs. La flexibilité, qui englobe des pratiques variées (télétravail, nomadisme, temps partiel, etc.), est devenue progressivement un levier stratégique majeur pour de nombreuses entreprises mais elle génère aussi de nombreux défis pour les managers. Cet ouvrage offre un regard large et novateur sur la flexibilité des modes d’organisation du travail. Après avoir décrit les caractéristiques de la flexibilité au travail, les auteurs s’intéressent au défi des compétences essentielles et proposent des conseils pratiques pour encourager une culture de flexibilité audacieuse. Ils présentent les différents outils et démarches à la disposition des services RH et des managers. En s’appuyant sur des recherches solides et des études de cas réelles, il propose des approches novatrices pour adapter les organisations aux nouvelles attentes des collaborateurs et appréhender de nouvelles pratiques managériales
On the cutoff phenomenon for fast diffusion and porous medium equations
No full text13 pagesThe cutoff phenomenon, conceptualized at the origin for finite Markov chains, states that for a parametric family of evolution equations, started from a point, the distance towards a long time equilibrium may become more and more abrupt for certain choices of initial conditions, when the parameter tends to infinity. This threshold phenomenon can be seen as a critical competition between trend to equilibrium and worst initial condition. In this note, we investigate this phenomenon beyond stochastic processes, in the context of the analysis of nonlinear partial differential equations, by proving cutoff for the fast diffusion and porous medium Fokker-Planck equations on the Euclidean space, when the dimension tends to infinity. We formulate the phenomenon using quadratic Wasserstein distance, as well as using specific relative entropy and Fisher information. Our high dimensional asymptotic analysis uses the exact solvability of the model involving Barenblatt profiles. It includes the Ornstein-Uhlenbeck dynamics as a special linear case
Conséquences de la pandémie de COVID-19 sur la mortalité, les parcours de soins et d’accompagnement de personnes en situation de handicap. L’exemple de trois pathologies invalidantes.
No full textThe COVID-19 pandemic had unprecedented health consequences. The health care system was quickly overwhelmed by patients and had to be reorganized. Treatment for other causes was then interrupted or postponed. The restrictions imposed have increased to these difficulties and had a detrimental effect on the support provided by professionals or relatives. Using qualitative and quantitative methods and two complementary data sources, this thesis aims to describe care and support trajectories, as well as mortality, for three specific populations. This will allow us to identify the changes that may have occurred during the pandemic and their short- and medium-term consequences. Beyond the results, the aim is to present a reproducible methodology for other populations.La pandémie de COVID-19 a entraîné des conséquences sanitaires inédites. Le système de soins s’est rapidement retrouvé submergé par les patients et des réorganisations ont été nécessaires pour les prendre en charge. Le recours aux soins pour d’autres causes que l’infection a alors été interrompu ou reporté. Les mesures de restriction mises en place ont participé à accroître ces difficultés et ont également eu un effet délétère sur l’accompagnement par des professionnels ou des proches. En s’appuyant sur des méthodes qualitatives et quantitatives ainsi que deux sources de données complémentaires, cette thèse s’attache à décrire les trajectoires de soins et d’accompagnement ainsi que la mortalité, pour trois populations spécifiques. Cela permet d’identifier les changements qui ont eu lieu pendant la pandémie et leurs conséquences à court ou moyen terme. Au-delà des résultats, l’objectif est de présenter une méthodologie reproductible pour d’autres populations
Asymptotic spectrum of weighted sample covariance: another proof of spectrum convergence
No full textWe propose another proof of the high dimensional spectrum convergence of the weighted sample covariance, more concise and self-sufficient but with stronger, but reasonable assumptions. We explain and illustrates this theorem for different weight distributions and show how the spectrum behaves in finite samples with heavy tails. The general purpose is to provide a detailed introduction to the high dimensional spectrum of weighted sample covariance
Credit constraints vs lack of demand. An analysis of Italian firms' borrowing demand in the construction industry
No full textThis paper seeks to better understand the factors influencing credit demand among Italian firms in the construction industry. Using data from the Bank of Italy's survey on construction firms for the period 2018-2022, we find that the majority of firms express no intention of applying for a loan. Two possible explanations for this limited engagement with the banking system are credit rationing by financial institutions and renewals of already existing credit lines. Additionally, we consider the possibility that firms may access credit through alternative means, including the illegal sector via mafia infiltration. Our analysis examines whether the lack of credit demand stems more from limited supply by financial intermediaries or from firms' disinterest in seeking formal loans. To explore this further, we combine the Bank of Italy survey data with records of property confiscations linked to mafia activity in the same province where firms are located. The findings suggest a positive correlation between mafia control of the territory and reduced demand for loans in the formal credit market
Which kind of policing for whom? Police and spatial segregation in France.
No full textInternational audienceThe concept of militarization has been used to analyse the increase and spread of policing in urban areas, particularly in working- and upper-class neighbourhoods, but with different forms in each case: in working-class neighbourhoods, militarization would mean the surveillance of the population who lives there, whereas in upper-class neighbourhoods it would be addressed to outsiders. The concept seems also more popular in research about Latin America than Europe. For this workshop, I propose to discuss the forms and limits of this concept by making a double movement. On the one hand, a movement from cities to rural and periurban areas: is the concept useful to understand what is going on in these areas? What are the geographical limits of militarization and what do these limits mean in terms of generalization? On the other hand, a movement from Argentina (where I accomplished previous research on gated communities) to France. Between 2014 and 2018 I carried out fieldwork in ten police units of the gendarmerie, in two regions of France, observing the everyday work of the gendarmes (123 days of observation) and making in-depth interviews with 46 of them. The French gendarmerie is the national police force who works in all over the territory except in cities with over 20 000 inhabitants – which are controlled by the police. During this fieldwork it appeared that policing differs according to the diversity of locations. Not only because of the social diversity and the different kinds of illegalisms in them, but also because of different resources and policies allocated by the police institutions to each one, as well as the way gendarmes classify the places where they are assigned to. The best career of a gendarme is related to the kind of location where he works (and lives) at the different steps of his professional life, and this influences professional socialisation – indeed, the “best career” of a gendarme begins in militarized working-class neighbourhoods and overseas territories. I propose then to look at the different categories of territories where gendarmes are assigned to by following the “best career” and its alternatives, to discuss militarization, policing and democracy
Bayesian Learning in Mean Field Games
No full textInternational audienceWe consider a mean-field game model where the cost functions depend on a fixed parameter, called \textit{state}, which is unknown to players. Players learn about the state from a a stream of private signals they receive throughout the game. We derive a mean field system satisfied by the equilibrium payoff of the game and prove existence of a solution under standard regularity assumptions. Additionally, we establish the uniqueness of the solution when the cost function satisfies the monotonicity assumption of Lasry and Lions at each state
Keras Sig: Efficient Path Signature Computation on GPU in Keras 3
No full textInternational audienceIn this paper we introduce Keras Sig a high-performance pythonic library designed to compute path signature for deep learning applications. Entirely built in Keras 3, Keras Sig leverages the seamless integration with the mostly used deep learning backends such as PyTorch, JAX and TensorFlow. Inspired by Kidger and Lyons [2021],we proposed a novel approach reshaping signature calculations to leverage GPUparallelism. This adjustment allows us to reduce the training time by 55% and 5 to 10-fold improvements in direct signature computation compared to existing methods, while maintaining similar CPU performance. Relying on high-level tensor operations instead of low-level C++ code, Keras Sig significantly reduces the versioning and compatibility issues commonly encountered in deep learning libraries, while delivering superior or comparable performance across various hardware configurations. We demonstrate through extensive benchmarking that our approach scales efficiently with the length of input sequences and maintains competitive performance across various signature parameters, though bounded by memory constraints for very large signature dimensions