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What Transition to Teach? Interview with Dominique Bourg
No full textInternational audienceDominique Bourg is a philosopher and honorary professor at the University of Lausanne (UNIL). He is the editor of the online journal lapenséeécologique.com and the author of several books about ecology, democracy and the impact of the market. In this interview he first talks about the initiatives, in teaching but also in university management, he is involved in, mainly in Lausanne. With regards to teaching, he shares his thoughts on how to introduce courses and he argues for a multidisciplinary and transdisciplinary approach of teaching ecological issues, combining the perspective of social sciences with sound scientific knowledge and eco-psychological support. The interview then adopts a broader angle by mentioning obstacles to the « transition », the need to change institutions at different scales, with taking into account long term issues in public decision-making and defining a common baseline for democracy. Finally Dominique Bourg explains which levers he considers most important on the local, national and international scale
A heuristic with a performance guarantee for the Commodity constrained Split Delivery Vehicle Routing Problem
No full textInternational audienceThe Commodity constrained Split Delivery Vehicle Routing Problem (C-SDVRP) is a routing problem where customer demands are composed of multiple commodities. A fleet of capacitated vehicles must serve customer demands in a way that minimizes the total routing costs. Vehicles can transport any set of commodities and customers are allowed to be visited multiple times. However, the demand for a single commodity must be delivered by one vehicle only. In this work, we developed a heuristic with a performance guarantee to solve the C-SDVRP. The proposed heuristic is based on a set covering formulation, where the exponentially-many variables correspond to routes. First, a subset of the variables is obtained by solving the linear relaxation of the formulation by means of a column generation approach which embeds a new pricing heuristic aimed to reduce the computational time. Solving the linear relaxation gives a valid lower bound used as a performance guarantee for the heuristic. Then, we devise a restricted master heuristic to provide good upper bounds: the formulation is restricted to the subset of variables found so far and solved as an integer program with a commercial solver. A local search based on a mathematical programming operator is applied to improve the solution. We test the heuristic algorithm on benchmark instances from the literature. Several new (best-known) solutions are found in reasonable computational time. The comparison with the state of the art heuristics for solving C-SDVRP shows that our approach significantly improves the solution time, while keeping a comparable solution quality
Explaining the Ammunition Shortage: The Show vs. Have Military Power Game
No full textThe return of high-intensity conflict at Europe's borders has exposed the massive underinvestment in ammunition by many Western states, relative to the normal availability of main weapons. This paper complements existing explanations for this relative imbalance with insights from a signaling game. In an environment of uncertain information, where neither military budgets nor investment in ammunition can be observed, low-budget states may imitate the procurement strategies of high-budget states to project an image of power. In this context, high-budget states have an incentive to over-invest in main weapons and neglect ammunition as a strategy to dissuade imitation by low-budget states. While this behavior may be rational in times of peace when perceptions may matter as much as capabilities, during wartime, the deficit in ammunition is extremely harmful, as it increases the likelihood of the opponent's victory
Mesurer l’impact social & l’ancrage territorial des entreprises
No full textThis study focuses on the impact of businesses through their corporate social and environmental responsibility policies and their patronage activities in fragile territories, including urban, peri-urban, and rural areas. To think about the role of a company is to question its contribution to human and sustainable development in territories that reflect different realities, depending on whether they concern a family (living area), an employer (employment zone, catchment area, etc.), or an elected official (electoral district). Every location with employees, customers, or suppliers requires a territorial anchoring of the company to ensure the sustainability of its activities and better cooperation with public actors and the social economy sector (ESS), in order to serve the community: the preservation of life, the dynamism of local life, and economic viability. The report has documented around a hundred business initiatives that provide answers to the challenges identified in these territories in areas such as social cohesion, mobility, inclusion, education, access to employment and training, support for ecological transition, food, healthcare and prevention, housing, and digital access.Through this inventory, the report examines the social, environmental, and economic inequalities that affect individuals, as well as the main contrasts in territories that companies must consider in their territorial engagement (regional metropolitan growth, distance from employment areas, industrial decline, wealth gaps, etc.). Furthermore, the analysis of economic, geographical, demographic, and ecological issues in territories, particularly in Île-de-France, Hauts-de-France, Auvergne-Rhône-Alpes, and overseas regions, is put into perspective with the numerous social challenges they face.After thirteen months of study and hearings, the working group developed a set of common impact measurement indicators for business actions, drawing from observed practices in the field and recommendations from the research community. These indicators allow for documenting, managing, and reporting on the impact produced by an organization, as well as uniting public and private stakeholders to measure the impact of their economic activities, improve data collection, harmonize practices, and speak a common language.The research also focuses on different business models, and the results of the working group highlight the importance of territorial anchoring for businesses, defined by their ability to integrate into the local fabric and governance and to initiate multi-stakeholder cooperation, as one of the conditions for generating social impact. This vision of corporate responsibility resonates with the call for a fairer transition, which encompasses the challenges of both ecological transition and social justice
STRATEGIC AND INSOLVENCY RISK IN SOVEREIGN DEBT PRICING: AN EXPERIMENTAL STUDY
No full textAfter the 2007 Global Financial Crisis, tensions in sovereign bond markets of advanced economies occurred quite frequently, driven by a combination of deteriorating fundamentals and self-fulfilling beliefs. However, it is difficult to disentangle empirically the contribution of these two factors in explaining government bond yields during episodes of sovereign debt distress. In this paper, we address this challenge through a controlled laboratory experiment. In the experiment, a government issues one-period bonds through a discriminatory price auction to finance a legacy of government debt. In a baseline treatment, sovereign default can result from investors' failure to coordinate in purchasing bonds (strategic risk) or the government debt reaching a solvency limit (fundamental risk). In a second treatment, a central bank intervenes as a bondholder-of-last-resort and eliminates roll-over defaults. We find that investors correctly price the probability of government default and demand higher interest rates as the risk of default increases. At the same time, the required risk premium is lower in the treatment with a central bank compared to the baseline treatment. The difference between interest rates across the two treatments can be viewed as the illiquidity component of sovereign debt risk.</div
Comparing Multivariate Distributions: A Novel Approach Using Optimal Transport-based Plots
No full textQuantile-Quantile (Q-Q) plots are widely used for assessing the distributional similarity between two datasets. Traditionally, Q-Q plots are constructed for univariate distributions, making them less effective in capturing complex dependencies present in multivariate data. In this paper, we propose a novel approach for constructing multivariate Q-Q plots, which extend the traditional Q-Q plot methodology-to handle high-dimensional data. Our approach utilizes optimal transport (OT) and entropy-regularized optimal transport (EOT) to align the empirical quantiles of the two datasets. Additionally, we introduce another technique based on OT and EOT potentials which can effectively compare two multivariate datasets. Through extensive simulations and real data examples, we demonstrate the effectiveness of our proposed approach in capturing multivariate dependencies and identifying distributional differences such as tail behaviour. We also propose two test statistics based on the Q-Q and potential plots to compare two distributions rigorously
Rivalry as a Contextual Factor of Gender Inequality in Network Returns
No full textInternational audienceAbstract Linking research on networks, rivalry, and gender, we develop a contextual approach to gender-based differences in network returns. Our principal contribution is in articulating the role of rivalry − a personalized and relational form of competition − in influencing the cognitive activation and behavioural mobilization of social networks. Three experiments and two field studies provide consistent evidence for a negative impact of rivalry on women's network activation and mobilization. We attribute this effect to the misalignment between the cognitive-relational schema associated with rivalry, promoting focus, agency, and confrontation, and gender-based cognitive and behavioural expectations, portraying women as more comprehensive, communal, and cooperative than men. The negative consequences of this misalignment are due to the experience of negative affect, fear of social evaluations, and perception of threat. A key takeaway from our analysis is that efforts at improving women's network returns should better account for the role of contextual factors
A branch-and-price method for the Multi-Commodity Ring Vehicle Routing Problem
No full textInternational audienc
Two extended formulations for the virtual network function placement and routing problem
No full textInternational audienceGiven a bi-directed graph modeling a telecommunication network, and a set of origin-destination pairs representing traffic requests (commodities) along with their associated Service Function Chains (SFCs), the Virtual Network Function Placement and Routing Problem (VNFPRP) aims to find, for each commodity, one latency-constrained routing path that visits the required Virtual Network Functions in a specific order. The function installation costs together with the node activation costs have to be minimized. In this paper, we present two extended Mixed Integer Programming (MIP) formulations to model the VNFPRP. For each formulation we define the master problem, the pricing problem, the associated Lagrangian bound and a specific branching scheme, in order to derive an efficient Branch-and-Price algorithm. We also provide several families of valid inequalities to strengthen the LP-relaxation bounds. Computational results are reported comparing the performance of the two Branch-and-Price algorithms with a compact MIP formulation and its Branch-and-Benders-cut implementation on a set of SNDlib instances representing telecommunication networks
Évaluation des réformes de la fiscalité du capital -Effets sur la création d'entreprises, l'expatriation et la circulation de l'épargne
No full textL’objectif affiché des réformes de la fiscalité du capital mises en place entre 2017 et 2018 était de baisser la fiscalité sur le capital afin de soutenir l’investissement privé, et in fine la croissance de l’économie française. L’enjeu d’évaluation est donc de pouvoir quantifier ces potentiels effets sur l’investissement, et plus généralement sur la circulation du capital dans l’économie.Les précédents travaux de recherche menés jusqu’à présent n’ont pas mis en évidenced’effets sur l’investissement de la mise en place du PFU pour les entreprises déjà existantes (Bach et al., 2021a), et le constat s’est avéré similaire pour la transformation de l’ISF en IFI (Bach et al., 2021b).La marge intensive de l’investissement ne semble donc pas être une marge de réponse comportementale majeure aux modifications de la fiscalité sur la distribution des revenus ou sur le stock de capital.Les travaux de recherche sur données françaises ont, par contre, mis en évidence une forte réaction de la distribution des revenus du capital à ces réformes, avec notamment une très forte hausse de la distribution des dividendes à la mise en place du PFU (Bach et al., 2019, 2021a), mais aussi à la mise en place de l’IFI avec la suppression du mécanisme du plafonnement (Bach et al., 2023).L’objectif de l’étude présentée dans ce rapport est de compléter ces travaux en mesurant l’impact des réformes du PFU et de l’IFI sur des décisions d’investissement à la marge extensive, c’est-à-dire correspondant à des choix discrets d’investissement comme la création d’entreprise, l’expatriation ou au retour d’entrepreneurs, et les décisions de réinvestissement de capital