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L’espace de travail : quand ce n’est plus (nécessairement) un lieu
No full textInternational audienceThe expressions “going to work” or “going to the office” associate work with a place, as if these two notions were necessarily intertwined. Yet this association between place and work is a relatively recent one. Before the Industrial Revolution, most tasks considered work were performed in or around the home, whether as a craft or tilling the soil. In the 19th century, the materiality of workplaces became more tangible, notably with the appearance of factories. However, with the evolution of technology and the emergence of the knowledge economy, is it still relevant to qualify work in terms of the place where it is carried out?Las expresiones «ir a trabajar» o «ir a la oficina» asocian el trabajo a un lugar, como si ambos conceptos estuvieran necesariamente entrelazados. Sin embargo, esta asociación entre lugar y trabajo es bastante reciente. Antes de la Revolución Industrial, la mayoría de las tareas consideradas como trabajo se realizaban en el hogar o cerca de él, ya fuera como oficio o labrando la tierra. En el siglo XIX, la naturaleza física de los lugares de trabajo se hizo más tangible, sobre todo con la aparición de las fábricas. Sin embargo, con la evolución de la tecnología y la aparición de la economía del conocimiento, ¿sigue siendo pertinente describir el trabajo en función del lugar donde se realiza?Les expressions « aller au travail » ou bien « aller au bureau » associent le travail à un lieu, comme si ces deux notions étaient nécessairement imbriquées. Pourtant, cette association entre lieu et travail est assez récente. Avant la Révolution industrielle, l’essentiel des tâches considérées comme du travail était réalisé au sein du foyer ou à proximité, qu’ils s’agissent d’une activité artisanale ou du labourage de la terre. Au XIXe siècle, la matérialité des lieux de travail est devenue plus tangible, avec notamment l’apparition d’usines. Cependant, avec l’évolution des technologies, et l’apparition de l’économie de la connaissance, est-il encore pertinent de qualifier le travail par rapport à l’endroit où il est effectué
On the roads and rivers of Late Iron Age Gaul: Adjusting least-cost path analysis to multiple means of transport and imprecise data
No full textInternational audienceCeltic societies at the end of the last millennium BCE experienced a shift in the scale of production and exchange, leading to a revolution in mobility. This study aims to investigate these ancient exchanges by focusing on their primary constraint: the difficulties of transportation. We seek to estimate the remoteness between sites from a merchant's perspective, considering transport costs, that is, the challenges of moving heavy and bulky goods over long distances.Our approach is based on Least-Cost Path (LCP) estimation, which we adapt to address the various complexities inherent in applying this method to ancient transportation systems. These complexities include the multimodal nature of transportation, involving inland transport, upstream and downstream fluvial navigation, and the lack of or imprecise nature of data regarding navigable sections and transportation costs. While LCPs are widely used in archaeological contexts, a standardised methodology for calibrating them and selecting algorithmic variants remains elusive, particularly when reference paths are absent.This article offers firstly a methodological contribution to the development and rational application of LCPs in archaeology, adapting them to the limitations of our data and the multimodal nature of goods transportation; and secondly an archaeological contribution demonstrating the crucial role of considering the constraints of ancient mobility in exploring the evolution of past societies' territories
Management et théorie : pourquoi ça compte [Lionel Garreau]
No full textXerfi Canal a reçu Lionel Garreau, Laboratoire Dauphine recherches en management (DRM équipe M-Lab), université Paris Dauphine, PSL, pour parler du management et de la théorie.Une interview menée par Jean-Philippe Denis
On the Distortion of Committee Election with 1-Euclidean Preferences and Few Distance Queries
No full textInternational audienceWe consider committee election of k ≥ 2 (out of m ≥ k + 1) candidates, where the voters and the candidates are associated with locations on the real line. Each voter's cardinal preferences over candidates correspond to her distance to the candidate locations, and each voter's cardinal preferences over committees is defined as her distance to the nearest candidate elected in the committee. We consider a setting where the true distances and the locations are unknown. We can nevertheless have access to degraded information which consists of an order of candidates for each voter. We investigate the best possible distortion (a worst-case performance criterion) wrt. the social cost achieved by deterministic committee election rules based on ordinal preferences submitted by n voters and few additional distance queries. For k = 2, we achieve bounded distortion without any distance queries; we show that the distortion is 3 for m = 3, and that the best possible distortion achieved by deterministic algorithms is at least n -1 and at most n + 1, for any m ≥ 4. For any k ≥ 3, we show that the best possible distortion of any deterministic algorithm that uses at most k -3 distance queries cannot be bounded by any function of n, m and k. We present deterministic algorithms for k-committee election with distortion of O(n) with O(k) distance queries and O(1) with O(k log n) distance queries.</div
Peut-on réduire les inégalités géographiques dans l’accès aux filières sélectives en France ?
No full textNotes IPP n°114Quel rôle joue la distance à la formation la plus proche dans les choix d’orientation ? À partir de données individuelles détaillées retraçant les parcours des élèves dans l’enseignement secondaire et supérieur, cette note apporte un nouvel éclairage sur cette question.Elle analyse l’impact de la création de classes préparatoires aux grandes écoles (CPGE) et de sections de technicien supérieur (STS) dites de « proximité » entre 2006 et 2015. En France, où il existe de nombreux freins à la mobilité étudiante, la répartition inégale de l’offre de formation sur le territoire contribue fortement aux disparités géographiques d’accès aux formations sélectives
Concentration inequalities and cut-off phenomena for penalized model selection within a basic Rademacher framework
No full textThis article exists first and foremost to contribute to a tribute to Patrick Cattiaux. One of the two authors has known Patrick Cattiaux for a very long time, and owes him a great deal. If we are to illustrate the adage that life is made up of chance, then what could be better than the meeting of two young people in the 80s, both of whom fell in love with the mathematics of randomness, and one of whom changed the other's life by letting him in on a secret: if you really believe in it, you can turn this passion into a profession. By another happy coincidence, this tribute comes at just the right time, as Michel Talagrand has been awarded the Abel prize. The temptation was therefore great to do a double. Following one of the many galleries opened up by mathematics, we shall first draw a link between the mathematics of Patrick Cattiaux and that of Michel Talagrand. Then we shall show how the abstract probabilistic material on the concentration of product measures thus revisited can be used to shed light on cut-off phenomena in our field of expertise, mathematical statistics. Nothing revolutionary here, as everyone knows the impact that Talagrand's work has had on the development of mathematical statistics since the late 90s, but we've chosen a very simple framework in which everything can be explained with minimal technicality, leaving the main ideas to the fore
« Faire avec le temps » : les pratiques temporelles des individus face à l’agence du temps
No full textManagement sciences and practicioners’ literature mainly considered time as an "available" resource. They privilege individuals’ temporel agency over time’s one. However, this relationship with time fails frequently. This is reflected in particular by schedules that are rarely respected. It seemed necessary to rebuild, based on management sciences, but also on philosophy, a theoretical framework allowing us to account for time’s agency. We focused on construction sites, whose numerous delays are well known. The study of construction managers’ temporal practices allowed us to discover and describe another relationship with time. We theorized it as « dealing with » time. Our work also contribute to the discipline of project management.Les sciences de gestion et la littérature dédiée aux praticiens appréhendent majoritairement le temps comme une ressource « à disposition ». Elles privilégient donc la capacité d’agir des individus sur le temps au détriment d’une réflexion sur l’agir du temps. Cependant, cette « mise à disposition » du temps connaît des échecs qui se traduisent notamment par des plannings rarement respectés. Il nous a paru nécessaire de rebâtir à partir des sciences de gestion, mais aussi de la philosophie, un cadre théorique permettant de rendre compte d’un agir du temps. Notre attention s’est par la suite portée sur les chantiers de construction, dont les nombreux retards sont bien connus. L’étude des pratiques temporelles des individus en charge de l’encadrement des travaux nous a permis de découvrir un autre rapport au temps de l’ordre du « faire avec » que nous avons décrit et théorisé. Notre travail présente également des contributions managériales à la discipline de la gestion de projet
Sortus Interruptus : Trier des phoques en O(n log(n))
No full textInternational audienceOpale, garde-faune en baie de Somme, souhaite trier une colonie de phoques par volume afin d'initier un suivi statistique. Elle ne peut pas mesurer directement le volume d'un animal, mais elle est capable de comparer deux individus. Le temps nécessaire à une telle comparaison est : relativement long, aléatoire (de distribution inconnue) et indépendant de la paire considérée. De plus, en raison des marées, Opale dispose d'un temps limité pour effectuer ses comparaisons. Elle aimerait donc pouvoir fournir un résultat, même approximatif, quoi qu'il arrive.Dans cet article, nous proposons d'aider Opale grâce aux tris interruptibles
A variational method for curve extraction
No full textInternational audienceWe propose a functional for extracting curves between a list of possible endpoints, based on a discretization of a variational energy and Smirnov's decomposition theorem for vector fields. It is then used to design a bi-level minimization approach to automatically extract curves and 1D structures from an image, which is mostly unsupervised
A NOTE ON CONTRACTIVE SEMI-GROUPS ON A 1:1 JUNCTION FOR SCALAR CONSERVATION LAWS AND HAMILTON-JACOBI EQUATIONS
No full textInternational audienceWe show that any continuous semi-group on which is (i) contractive, (ii) satisfies the conservation law in (for a space discontinuous flux H(x,p)= H^l(p) {\bf 1}_{x<0}+ H^r(p) {\bf 1}_{x>0}), and (iii) satisfies natural continuity and scaling properties, is necessarily given by a germ condition at the junction: a.e., where is a maximal, dissipative and complete germ. In a symmetric way, we prove that any continuous semi-group on which is (i) contractive, (ii) satisfies with the Hamilton-Jacobi equation in (for a space discontinuous Hamiltonian as above), and (iii) satisfies natural continuity and scaling properties, is necessarily given by a flux limited solution of the Hamilton-Jacobi equation