Archive ouverte de l'ESSEC Business School
Not a member yet
1344 research outputs found
Sort by
Thinning out Steiner trees: a node-based model for uniform edge costs
No full textInternational audienceThe Steiner tree problem is a challenging NP-hard problem. Many hard instances of this problem are publicly available, that are still unsolved by state-of-the-art branch-and-cut codes. A typical strategy to attack these instances is to enrich the polyhedral description of the problem, and/or to implement more and more sophisticated separation procedures and branching strategies. In this paper we investigate the opposite viewpoint, and try to make the solution method as simple as possible while working on the modeling side. Our working hypothesis is that the extreme hardness of some classes of instances mainly comes from over-modeling, and that some instances can become quite easy to solve when a simpler model is considered. In other words, we aim at “thinning out” the usual models for the sake of getting a more agile framework. In particular, we focus on a model that only involves node variables, which is rather appealing for the “uniform” cases where all edges have the same cost. In our computational study, we first show that this new model allows one to quickly produce very good (sometimes proven optimal) solutions for notoriously hard instances from the literature. In some cases, our approach takes just few seconds to prove optimality for instances never solved (even after days of computation) by the standard methods. Moreover, we report improved solutions for several SteinLib instances, including the (in)famous hypercube ones. We also demonstrate how to build a unified solver on top of the new node-based model and the previous state-of-the-art model (defined in the space of arc and node variables). The solver relies on local branching, initialization heuristics, preprocessing and local search procedures. A filtering mechanism is applied to automatically select the best algorithmic ingredients for each instance individually. The presented solver is the winner of the DIMACS Challenge on Steiner trees in most of the considered categories
Mirroring Hypothesis and Integrality in the Electric Vehicle Industry: Evidence from Tesla Motors.
No full textInternational audienc
Diversification benefits under multivariate second order regular variation
No full textWe analyze risk diversification in a portfolio of heavy-tailed risk factors under the assumption of second order multivariate regular variation. Asymptotic limits for a measure of diversification benefit are obtained when considering, for instance, the value-at-risk . The asymptotic limits are computed in a few examples exhibiting a variety of different assumptions made on marginal or joint distributions. This study ties up existing related results available in the literature under a broader umbrella
Robustness of Multistep Forecasts and Predictive Regressions at Intermediate and Long Horizons.
No full textThis paper studies the properties of multi-step projections, and forecasts that are obtained using either iterated or direct methods. The models considered are local asymptotic: they allow for a near unit root and a local to zero drift. We treat short, intermediate and long term forecasting by considering the horizon in relation to the observable sample size. We show the implication of our results for models of predictive regressions used in the financial literature. We show here that direct projection methods at intermediate and long horizons are robust to the potential misspecification of the serial correlation of the regression errors. We therefore recommend, for better global power in predictive regressions, a combination of test statistics with and without autocorrelation correction
Guidelines for Web Application Designers: A Meta-Model, a Grammar, and a Tool
No full textInternational audienc
Fetish, magic, marketing
No full textInternational audienceThis article identifies specific forms of fetishistic enchantments produced by practices culturally specific to modern consumer culture. The authors show that magical practices are constitutive of two fetishistic marketing constructs: the consumer and the human luxury brand. Marketing magic enacts relations between man and the transcendent by bringing consumer personas ‘to life’ and manifesting ideals of the beautiful in luxury. Marketing magic is a practice of power – non-rationalist strategies for resolving intractable social problems. Consumer ‘personas’ create the manageable consumer interlocutors for companies. Charismatic creative directors seem to evade the iron logic of commodity relationships via the magical conjuring of their own personas and of artful luxury.<br/
Collaborative management control package, risks, and performance
No full textInternational audienceThis study aims to deepen knowledge about appropriate control devices in interfirm settings. By proposing a “collaborative management control package” (CMPC), the authors identify which components of the CMCP mitigate transaction risks (transaction scope and dependence) and influence organizational performance. To test the hypotheses contained in the proposed conceptual framework, this study investigates 207 buyer–supplier collaborative relationships. The findings establish the global approach of CMCP and its link to organizational performance, in response to calls in prior literature for new research that reveals how the links among various controls might influence both firm and collaborative performance
A narrative approach to publishing information systems research: inspiration from the French New Novel tradition
No full textInternational audienc
Group Gender Composition and Economic Decision-Making: Evidence from the Kallystée Business Game
No full textThis paper analyses data collected in 2012 and 2013 at the ESSEC Business School from Kallystée, a proprietary mass-attendance business game. Company boards are simulated by teams of five students selected at random. The design manipulates the gender composition of the boards to allow for all possible gender combinations. Data show that all-men and mixed teams with four women perform significantly better than all-women teams. However, when controlling for the average tolerance to risk score of the teams, the performance advantage of all-men teams vanishes, while the team-specific economic performance of teams with four women is still positive and strong. Teams with four women take more risks than the team tolerance to risk score would predict, which suggests some form of team specific action bias or risk-shift
An attitude model of environmental action : evidence from developing and developed countries
No full textThis paper analyzes the determinants of individual attitudes towards environmental action by means of an original PLSPM model of Environmental Awareness-Social Capital-Action (EASCA). Estimates build on survey data on 34.612 individuals from 42 different countries, as provided in the fifth wave of the World Value Survey (2005-2009). Besides the benchmark global estimates, we perform subsample analysis for developed and developing countries, as well as country analyses for four major economies: China, India, Germany and the United States. Doing so allows us to underline structural differences between countries or main groups of countries. In particular, we find that environmental awareness and trust in not-for profit organizations are the main determinants of individual action in support of environmentally friendly policies. The quality of environmental policymaking should improve if these cultural differences are better understood and taken into account