HAL-Ecole des Ponts ParisTech
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Evaluating the robustness of the ARIO model for a local disaster: 2021 flooding in Germany
No full textInternational audienceGiven the interconnectedness of modern economies and the widespread adoption of just-in-time production methods, even minor disruptions caused by natural disasters can lead to substantial indirect economic impact. A substantial body of literature has explored this phenomenon, using input-output analysis, computable general equilibrium and agent-based models. However, these models (i) heavily rely on parameters and data that often lack empirical grounding or (ii) exhibit considerable uncertainty, making it challenging to assess their reliability. The ARIO model has been widely used in the literature and has provided theoretical foundation for several related models. Using the July 2021 floods in Germany as a case study, we assess the sensitivity of the results of this model by varying key parameters, as well as the multi-regional input-output tables (MRIOTs), which constitute its primary input data. To facilitate this analysis, we introduce a new, resource-efficient Python implementation of the ARIO model, enabling the execution of a large number of simulations. Our findings highlight the substantial impact of data source and parameter selection on model outcomes, especially so when post-disaster rebuilding is costly. To ensure the robustness of their results, future studies on indirect economic impacts should be careful about recovery dynamics, consider multiple scenarios and compare results using MRIOTs from various sources
Innovation and inequalities
No full textInternational audienceInnovation is a key source of sustainable growth, but it can affect inequalities in many ways—increasing some inequalities and decreasing others. The impact of any particular innovation on inequalities will depend importantly on who controls the property rights to exploit the innovation and what they decide to do with it. The introduction of an innovation can affect the power of different actors in a market, the way markets work, and the returns to different attributes of actors in the market. All of these factors and more will influence how innovation affects inequalities. We would like policy to encourage innovation while making sure that yesterday's innovators do not use their rents to deter innovation by new entrants, thereby eventually undermining productivity growth and social mobility, and increasing inequalities. This requires a combination of regulation, progressive taxation, and enlightened competition policy
An Algorithmic Framework for Locally Constrained Homomorphisms
No full textInternational audienceA homomorphism φ from a guest graph G to a host graph H is locally bijective, injective or surjective if for every u ∈ V (G), the restriction of φ to the neighbourhood of u is bijective, injective or surjective, respectively. We prove a number of new FPT, W[1]-hard and paraNP-complete results for the corresponding decision problems LBHom, LIHom and LSHom by considering a hierarchy of parameters of the guest graph G. In this way we strengthen several existing results. For our FPT results, we develop a new algorithmic framework that involves a general ILP model. We also use our framework to prove FPT results for the Role Assignment problem, which originates from social network theory and is closely related to locally surjective homomorphisms
Large-scale destratification in the Eurasian Basin thermocline and consequences on the Atlantic Water shoaling
No full textInternational audienceContext: an uncertain future for the Eurasian Basin (EB) stratificationMethod: a clustering algorithm to define regions with coherent profilesResults: AW shoaling and destratificatio
Histoire de la Fédération nationale des collectivités concédantes et régies (FNCCR). 90 ans en faveur des services publics en réseaux dans les territoires
No full textNational audienc
Looking for the Bright Side of the China Syndrome: Rising Export Opportunities and Life Satisfaction in China
No full textInternational audienceLooking for the Bright Side of the China Syndrome: Rising Export Opportunities and Life Satisfaction in Chin
2023: Weather and Climate Extremes Hitting the Globe with Emerging Features
No full textInternational audienceGlobally, 2023 was the warmest observed year on record since at least 1850 and, according to proxy evidence, possibly of the past 100 000 years. As in recent years, the record warmth has again been accompanied with yet more extreme weather and climate events throughout the world. Here, we provide an overview of those of 2023, with details and key background causes to help build upon our understanding of the roles of internal climate variability and anthropogenic climate change. We also highlight emerging features associated with some of these extreme events. Hot extremes are occurring earlier in the year, and increasingly simultaneously in differing parts of the world (e.g., the concurrent hot extremes in the Northern Hemisphere in July 2023). Intense cyclones are exacerbating precipitation extremes (e.g., the North China flooding in July and the Libya flooding in September). Droughts in some regions (e.g., California and the Horn of Africa) have transitioned into flood conditions. Climate extremes also show increasing interactions with ecosystems via wildfires (e.g., those in Hawaii in August and in Canada from spring to autumn 2023) and sandstorms (e.g., those in Mongolia in April 2023). Finally, we also consider the challenges to research that these emerging characteristics present for the strategy and practice of adaptation
Advancing Corporate Tax Transparency
No full textMultinational enterprises have risen to become dominant forces in the global economy, accompanied by a troubling trend of aggressive tax avoidance. In 2022 alone, an estimated $1 trillion in profits was shifted to tax havens by multinationals, amounting to 35% of all profits booked outside their headquarters countries (Alstadsæter et al., 2023). Despite tax avoidance being a major public concern, the specific practices employed by individual companies have remained largely opaque to the public due to a lack of transparency and public disclosure obligations. Comprehensive transparency measures promote informed policymaking, accountability, public trust, and sustainable development globally. This report examines the current landscape of corporate tax transparency and evaluates how emerging transparency measures could shape future developments in this critical area.We focus on corporate tax transparency measures via Country-by-Country Reporting (CbCR), where multinationals disclose detailed financial and tax-related information for each country of operation. We collected the publicly available CbCR reports and compiled them into a single database: the Public CbCR Database.This new data source highlights that large multinationals, particularly from Western Europe, are leading the way as primary publishers of such reports. Overall, the large multinationals publishing public CbCR account for less than 2% of large companies, and less than 5% of global revenues and global profits. Despite the small numbers, our research reveals an upward trend in voluntary CbCR disclosures, signalling increasing tax transparency practices. However, significant gaps remain, as U.S. multinationals and firms from major economies like China and Russia have only a few CbCR disclosures available.The European Union (EU) made an important step in furthering corporate tax transparency by adopting a mandatory CbCR directive that started applying this year in many EU countries. Our simulations reveal the impact this directive will have. Nearly one-third of large U.S. MNEs will be compelled to publish more disaggregated financial information than ever before publicly available. The increased disclosure from these U.S. corporate giants, who have historically been opaque, could be a breakthrough in tax transparency. However, the directive has serious limitations, as the requirements for geographical disaggregations are largely insufficient to truly evaluate the activity of multinationals. Broader adoption and enhancement of corporate tax transparency initiatives are crucial, we suggest several ways to improve the directive going forward
Environmental life-cycle impacts of bitumen: Systematic review and new Canadian models
No full textInternational audienceBitumen − or asphalt binder − is a major contributor to pavement environmental impacts. Nevertheless, the literature only counts scarce asphalt binder LCAs, with highly variable results. To better understand bitumen environmental impacts, we review LCAs published before 2024. Then, we build bitumen LCA models for different Canadian markets, using TRACI 2.1 and ecoinvent v3.6. The carbon footprint of Canadian asphalt binders ranges within [826–1098] kgCO2eq/t (potentially up to 2680 kgCO2eq/t when including fugitive emissions). Crude oil extraction is the main contributor to most life cycle environmental impact categories, but likely still underestimated. Transportation impacts can vary highly ([18–291] kgCO2eq/t in Canada). Models for these two hotspots must be tailored. Finally, we critically compare the carbon footprints of all published virgin asphalt binders LCAs: previous carbon footprints range within [143–637] kgCO2eq/t and are very likely underestimated. Previous pavement LCA results must be questioned, and higher-quality LCIs urgently developed to produce robust regionalized LCA-based recommendations on pavement green practices
On-line and in-line quality assessment across all scale levels of 3D concrete printing
No full textInternational audience3D Concrete printing requires much more elaborate quality control procedures compared to conventional concrete processing. Due to the various process steps, and the corresponding variation in material behaviour, time-, and length-scales, a single quality indicator and measurement technique (similar to the ‘slump test’ for traditional construction) cannot be selected. Instead, three families of quality indicators have been established: homogeneity during material production and deposition (quality variations), material evolution during printing (transient material behaviour), and macroscopic features and geometric conformity during printing and of the final object (geometry). For each family, quality assessment techniques which have been proven in other fields or for different applications, have been successfully transferred and adapted to the 3DCP process. In some cases, completely new methods have been developed. This paper aims to provide the state-of-the-art in such quality assessment methods, indicating high potential methods and research gaps across all scale levels of 3D concrete printing processes