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On the (Ir)Relevance of Discount Factors for Future Allocations of Scarce Resources
No full textThis article is interested in future allocations of scarce resources in an environment where upper bounds and lower bounds are fixed on the stream of consumptions or extractions of the scarce resource. It is shown that we can compute the optimal planning of consumptions independently from an explicit sequence of discounting factors as soon as they are decreasing at a rate smaller than a bound linked to the concavity of the utility function and the choice of the sequences of lower and upper bounds. The optimal solution is unique and exhibits two regimes with a pivotal period in the middle. Therefore, one gets plans satisfying some kind of intergenerational fairness: while the highest e ort is supported by the first generations, it then decreases for the remaining ones. The argument is then extended to partially renewable resources. Finally, we consider the role of the horizon and of a potential regret after a revision for the bounds
Mars as a Planet B?
No full textInternational audienceThe concept of terraforming Mars has been popularized in pop culture and recently by Elon Musk. The objective is to transform Mars into a planet suitable for habitation by living organisms and humans. Conceptually, this may be achieved in different steps: firstly, by increasing the atmospheric pressure of the whole planet to allow human beings to perform outdoor activities, possibly equipped with only an oxygen mask and without a pressurized suit. Secondly, by transforming the environment to make terrestrial organisms able to survive and proliferate. Thirdly, by creating a breathable atmosphere. The process would require a strong thickening of the atmosphere. A method to restore the early Mars CO2 atmosphere had been hypothesized in the 1990s, but after 30 years of Mars exploration, its feasibility is strongly questioned. Even if terraforming became possible, implementing it would violate many principles of modern environmental ethics. Assuming it is done for the purpose of habitation, it would also raise many legal and societal issues, pertaining notably to the relationships between communities on Mars and the Earth’s populations, structures, and rules
How large is "large enough" ? Large-scale experimental investigation of the reliability of confidence measures
No full textWhether individuals feel confident about their own actions, choices, or statements being correct, and how these confidence levels differ between individuals are two key primitives for countless behavioral theories and phenomena. In cognitive tasks, individual confidence is typically measured as the average of reports about choice accuracy, but how reliable is the resulting characterization of within-and between-individual confidence remains surprisingly undocumented. Here, we perform a large-scale resampling exercise in the Confidence Database to investigate the reliability of individual confidence estimates, and of comparisons across individuals' confidence levels. Our results show that confidence estimates are more stable than their choice-accuracy counterpart, reaching a reliability plateau after roughly 50 trials, regardless of a number of task design characteristics. While constituting a reliability upper-bound for task-based confidence measures, and thereby leaving open the question of the reliability of the construct itself, these results characterize the robustness of past and future task designs
Transport policy at an impasse: managing on-street delivery areas in Paris
No full textInternational audienc
Structure of Riemann solvers on networks (preliminary version 2)
No full textInternational audienceIn this paper we consider scalar Riemann solvers on networks, associated to scalar conservation laws. A junction is a particular network which is a finite set of half lines glued together at the origin. Riemann solvers solve uniquely the Riemann problem on the junction. We also assume that Riemann solutions are stable by passage to the limit.In part I of the paper, we only address fundamental questions concerning Riemann problems on junctions. We show a characterization of Riemann solvers either by their set of stationary solutions (the germ), or equivalently by their Godunov flux at the junction. Moreover, we show that the gluing of two junctions with Riemann solvers is well defined and leads to a new junction with a new Riemann solver. Because our theory is quite general, it encompasses in particular Kruzkov germs, Hamilton-Jacobi germs, monotone germs, conservative and non-conservative germs.In part II of the paper, we give an existence and uniqueness theory for conservation laws on networks in the special case where Riemann solvers are associated to Kruzkov germs
Diversity and social capital within the workplace: Evidence from Britain
No full textInternational audienceThis article uses the British Workplace Employee Relations Survey to investigate the links between gender or ethnic diversity and workers' level of trust in managers or the extent of identity with the values and objectives of the firm – dimensions of what we might call social capital within the workplace. These are both factors that one might expect to make firms more cooperative and, hence, productive. Controlling for plants workforce composition, we find an opposite effect of females and ethnic minorities: a higher female share in the plant is associated with higher trust and identity for both men and women (men much more than women), while a higher minority share is associated with lower trust and identity
Found in Translation: semantic approaches for enhancing AI interpretability in face verification
No full textThe increasing complexity of machine learning models in computer vision, particularly in face verification, requires the development of explainable artificial intelligence (XAI) to enhance interpretability and transparency. This study extends previous work by integrating semantic concepts derived from human cognitive processes into XAI frameworks to bridge the comprehension gap between model outputs and human understanding. We propose a novel approach combining global and local explanations, using semantic features defined by user-selected facial landmarks to generate similarity maps and textual explanations via large language models (LLMs). The methodology was validated through quantitative experiments and user feedback, demonstrating improved interpretability. Results indicate that our semantic-based approach, particularly the most detailed set, offers a more nuanced understanding of model decisions than traditional methods. User studies highlight a preference for our semantic explanations over traditional pixelbased heatmaps, emphasizing the benefits of human-centric interpretability in AI. This work contributes to the ongoing efforts to create XAI frameworks that align AI models behaviour with human cognitive processes, fostering trust and acceptance in critical applications
Improving monitoring of dissolved organic matter from the wastewater treatment plant to the receiving environment: A new high-frequency in situ fluorescence sensor capable of analyzing 29 pairs of Ex/Em wavelengths
No full textInternational audienc
Do disinflation policies ravage central bank finances?
No full textInternational audienceAdvanced-economy central banks are currently experiencing losses. To examine how rate-tightening cycles affect central bank finances, we study the financial statements of ten advanced-economy central banks during the 1970s and 1980s, the most notable and comparable policy environment to the present. We find that central bank profits actually increased in response to the anti-inflationary measures of the 1980s. We thus discuss how central bank profits depend on their policy instruments as well as their balance-sheet position when rate tightening begins, rather than on the tightening per se. Unlike today, central banks in the 1980s avoided losses because they did not remunerate bank reserves and their balance sheets did not carry the legacy of a decade of large asset purchases at low interest rates and long maturity. Our counterfactuals show that only a combination of these factors could have triggered losses in the 1980s: none of them is sufficient on its own. When losses emerged in the late 1970s, before the Volcker shock, they were due to foreign exchange reserves depreciating. In these instances, when central banks carried them forward and did not rely on transfers from the government, there was no loss of central bank independence or their ability to fight inflation
Effectiveness of ex ante honesty oaths in reducing dishonesty depends on content
No full textInternational audienceDishonest behaviours such as tax evasion impose significant societal costs. Ex ante honesty oaths—commitments to honesty before action—have been proposed as interventions to counteract dishonest behaviour, but the heterogeneity in findings across operationalizations calls their effectiveness into question. We tested 21 honesty oaths (including a baseline oath)—proposed, evaluated and selected by 44 expert researchers—and a no-oath condition in a megastudy involving 21,506 UK and US participants from Prolific.com who played an incentivized tax evasion game online. Of the 21 interventions, 10 significantly improved tax compliance by 4.5 to 8.5 percentage points, with the most successful nearly halving tax evasion. Limited evidence for moderators was found. Experts and laypeople failed to predict the most effective interventions, though experts’ predictions were more accurate. In conclusion, honesty oaths were effective in curbing dishonesty, but their effectiveness varied depending on content. These findings can help design impactful interventions to curb dishonesty