Archive ouverte de l'ESSEC Business School
Not a member yet
1344 research outputs found
Sort by
Who should pay the bill for employee upskilling?
No full textUpskilling is an investment in human capital that allows a worker to successfully undertake a new task or new project within his/her existing job. It involves costly effort on behalf of the employee to acquire new skills and new knowledge. A firm-financed training scheme allows to screen the applicants to the programme, but comes with the cost of hidden actions, as some employees train on their own yet keep on working on low-value projects. A laissez - faire policy relying on worker self-training and incentive compatible contracts allows to attract more workers to high-value projects, yet it must grant to flexible workers a positive informational rent. The profit comparison reveals a paradoxical situation where it might be in the interest of a company to rely on worker self-training rather than to provide a training programme
Outliers Detection in Networks with Missing Links
No full textInternational audienceOutliers arise in networks due to different reasons such as fraudulent behavior of malicious users or default in measurement instruments and can significantly impair network analyses. In addition, real-life networks are likely to be incompletely observed, with missing links due to individual non-response or machine failures. Identifying outliers in the presence of missing links is therefore a crucial problem in network analysis. In this work, we introduce a new algorithm to detect outliers in a network that simultaneously predicts the missing links. The proposed method is statistically sound: we prove that, under fairly general assumptions, our algorithm exactly detects the outliers, and achieves the best known error for the prediction of missing links with polynomial computation cost. It is also computationally efficient: we prove sub-linear convergence of our algorithm. We provide a simulation study which demonstrates the good behavior of the algorithm in terms of outliers detection and prediction of the missing links. We also illustrate the method with an application in epidemiology, and with the analysis of a political Twitter network. The method is freely available as an R package on the Comprehensive R Archive Network
Conception de Bases de Données Prosopographiques en Histoire - Un État de l'Art
No full textInternational audienceProsopography aims to study similarities in the trajectories of people in their biography. It is based on a database containing information relating to people from a specific environment defined chronologically and geographically. The objective of this article is to propose a state of the art of prosopographic databases emphasizing its specific concepts and the research relating to the modeling of these concepts. We present different definitions of prosopography. Then we describe the prosopographic method which has undergone a certain evolution due to the use of computerized databases. An overview of these prosopographic databases is presented, highlighting their advantages and limitations. The main concepts of these systems are described, including the person who is the central concept, the onomastics which allows the study of the names of people and institutions and the biographical notes which list the events to which people are linked. The description of these events raises the problem of time and its representation. All the information thus considered is associated with a level of uncertainty and imprecision, even contradiction. The information comes from historical sources whose credibility is essential. These concepts are sometimes modeled. We present the main conceptual prosopographic models, including ontological approaches. The conclusion opens towards the lines of research to be pursued in this field.La prosopographie a pour but l'étude de similitudes de trajectoires des personnes dans leur parcours biographique. Elle s'appuie sur une base de données contenant des informations relatives à des personnes d'un milieu spécifique définies chronologiquement et géographiquement. L'objectif de cet article est de proposer un état de l'art des bases de données prosopographiques mettant l'accent sur ses concepts spécifiques et la recherche afférente à la modélisation de ces concepts. Nous présentons différentes définitions de la prosopographie. Puis nous décrivons la méthode prosopographique qui a connu une certaine évolution du fait du recours aux bases de données informatisées. Un panorama de ces bases de données prosopographiques est présenté en soulignant leurs avantages et leurs limites. Les principaux concepts de ces systèmes sont décrits, notamment la personne qui est le concept central, l'onomastique qui permet l'étude des noms des personnes et des institutions et les notices biographiques qui recensent les événements auxquels les personnes sont liées. La description de ces événements pose le problème du temps et de sa représentation. Toutes les informations ainsi considérées sont entachées d'un niveau d'incertitude et d'imprécision, voire de contradiction. Les informations sont issues de sources historiques dont la crédibilité est primordiale. Ces concepts font parfois l'objet d'une modélisation. Nous présentons les principaux modèles conceptuels prosopographiques, inclus les approches ontologiques. La conclusion ouvre vers les axes de recherche à poursuivre dans ce domaine
Downstream mergers in vertically related markets with capacity constraints
No full textInternational audienceMotivated by a recent merger proposal in the French outdoor advertising market, we develop a model in which firms are initially endowed with some advertising capacities and compete on two fronts. First, firms compete to acquire additional advertising capacities on an upstream market; a first stage modeled as a second-price auction with externalities. Second, those firms, privately informed on their own costs, use their capacities on the downstream market to supply advertisers whose demand is random; a second stage modeled by means of mechanism design techniques. We study the linkages between the equilibrium outcomes on both markets. When a firm is endowed with more initial capacity, through the acquisition of a competitor for instance, whether it becomes more or less eager to acquire extra capacity on the upstream market depends a priori on fine details of the downstream market. Under reasonable choices of functional forms, we demonstrate that a downstream merger does not create any bias in the upstream market towards the already dominant firm. (C) 2020 Elsevier B.V. All rights reserved
Dynamics of Biofuel Prices on the European Market : Impact of the EU Environmental policy on the resources markets: Cahiers de l'Economie, Série Recherche, n° 137
No full textThis paper aims at explaining the major drivers of biodiesel market prices by examining agricultural resource prices and gasoil prices for automotive fuels in the context of the EU environmental policy. The EU policy has enhanced biodiesel production since 2006. Biodiesel prices are impacted by the EU policy as well as rapeseed and oil prices which have fluctuated a lot over the last decade. An econometric analysis was performed using monthly data from November 2006 to January 2016. However, tests for structural breaks show several changes in price behavior. This leads us to estimate a regime-switching model which reveals two main regimes for the biodiesel price pattern. When oil prices are high, biodiesel, rapeseed anddiesel oil prices are related, mainly driven by oil prices. When oil prices are low, biodiesel prices are mostly related to rapeseed prices according to EU regulations requiring the of biodiesel and gasoil
Trajectoire de Crise, Adaptation des organisations aux crises sanitaires, économiques et sociales de la Covid-19
No full textInternational audienc
The persistence of accountant beancounter images in popular culture
No full textInternational audiencePurpose :In analysing the beancounter image's trajectory, from its birth to its persistence, in European French language comics between 1945 and 2016, this paper explores why artists continue beancounter image usage in popular culture.Design/methodology/approach :Beancounter characters have been studied in an application of Iconology (Panofsky, 1955) in order to unravel how individuals make sense of cultural artefacts and how, in turn, the visuals shape cultural belief systems at a given time.Findings :This study reveals that comics artists usage of the beancounter image results from their critical reactions to management and capitalism whilst at other times the usage is an indication of authenticity. Motivation for the usage is not constant over time nor is the impact of the beancounter image. Both appear dependant of the level of artistic freedom experienced by the artist.Research limitations/implications :Based on a single media (comics) with a unique characters (European French language) this study deepens exploration of the ways in which accounting becomes entwined with the everyday and implies that further research is needed.Originality/value :Extends the work of Smith and Jacobs (2011) and Jacobs and Evans (2012) by focusing on a genre of popular culture over a long period, and by adopting a critical viewpoint. Also expands the possible applications of Panofsky's (1955) Iconology in accounting studies
Use and abuse of regulated prices in electricity markets: “How to regulate regulated prices?”
No full textInternational audienceWe consider the regulation of the tariffs charged by a public utility in the electricity sector. Consumers differ in terms of their privately known demands. When regulating a firm's tariffs, the government is concerned by the redistribution across consumer classes. A conflict between redistribution and screening induces pricing distortions when the firm is a monopoly. Introducing competition with an unregulated fringe improves efficiency but jeopardizes redistribution. In response to this problem, the government may now want to manipulate information about the incumbent's cost to restrict entry and better promote its own redistributive objective. To prevent such obstacle to entry, the government's discretion in fixing the incumbent's regulated tariffs should be restricted by imposing floors or caps on those tariffs and/or by controlling the market share left to the competitive fringe. We highlight the determinants of such limits on discretion and unveil to what extent they depend on the government's redistributive concerns