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Taming impulsive high-frequency data using optimal sampling periods
No full textInternational audienceOptimal sampling period selection for high-frequency data is at the core of financial instruments based on algorithmic trading. The unique features of such data, absent in data measured at lower frequencies, raise significant challenges to their statistical analysis and econometric modelling, especially in the case of heavy-tailed data exhibiting outliers and rare events much more frequently. To address this problem, this paper proposes a new methodology for optimal sampling period selection, which better adapts to heavy-tailed statistics of high-frequency financial data. In particular, the novel concept of the degree of impulsiveness (DoI) is introduced first based on alpha-stable distributions, as an alternative source of information for characterising a broad range of impulsive behaviours. Then, a DoI-based generalised volatility signature plot is defined, which is further employed for determining the optimal sampling period. The performance of our method is evaluated in the case of risk quantification for high-frequency indexes, demonstrating a significantly improved accuracy when compared against the well-established volatility-based approach. © 2023, The Author(s)
Aménités territoriales et dérèglement climatique : quelles conséquences pour les modèles de développement résidentiels des communes littorales de la région Provence-Alpes Côte d’Azur ?
No full textInternational audienceLes différents changements climatiques en cours et à venir impactent de manière conséquente la région Provence-Alpes Côte d’Azur (PACA). Au travers d’une approche pluridisciplinaire et exploratoire, cet article vise à tracer une typologie des développements résidentiels des communes littorales. À partir des statistiques (Corine Land Cover, 2018) et de la cartographie présentée dans cet article, les résultats décrivent une région PACA caractérisée par un défi d’adaptation faible et un défi d’atténuation élevé. À cet effet, au regard de nouvelles contraintes imposées par la loi climat et résilience, une efficacité sur ce degré de gravité du dérèglement climatique peut être envisagée. Cet instrument juridique ne devrait pas agir seul mais en se combinant à d’autres mécanismes financiers. Classification JEL : K32, Q51, Q54, R1
Réinventer les Chemins de Saint-Jacques de Compostelle en mesurant les attentes des pèlerins
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Endometriosis, infertility and occupational life: women's plea for recognition
No full textInternational audienceThe objective of this study was to explore and describe the specificities of the occupational life of infertile endometriotic women treated by in vitro fertilization. We conducted a qualitative monocentric study between December 2020 and June 2021. Twelve semi-structured in-depth interviews using a theme-based interview guide with open questions were undertaken with infertile women with deep infiltrating endometriosis. Data analysis was conducted using an inductive approach according to the grounded theory method. Three main themes emerged from the interviews: (i) barriers to reconciling illness and work life, (ii) facilitating factors for well-being at work, and (iii) consequences and outlooks. It appeared that the time of infertility treatment represents a particular period of change in the working lives of women with endometriosis. For most women, these changes are experienced negatively, often with a renunciation of goals. For others, this is the time to communicate the difficulties linked to their illness to their professional entourage. There is a long path ahead to finally achieving recognition of endometriosis in the context of professional life
Accounting for Climate When Determining the Impact of Weather on Retail Sales
No full textInternational audienceIn this paper, we explore the importance of accounting for climate when determining the impact of weather on product sales. Using a France-wide scanner panel dataset provided by our industry partner, we show that if climate is not accounted for, product categories may be misclassified as being weather sensitive when they are not, and vice versa. This is motivated by previous research and industry reports that suggest a relationship between weather and retail sales. However, these studies often fail to distinguish between weather and climate, leading to inaccurate conclusions. Our results highlight the need to control for climate in order to accurately assess the effects of weather on retail sales. We use ordinary least squares regression to estimate the relationship between temperature and sales for 29 different product categories. The regression models control for various factors, including shelf space allocation, week of observation, quantity purchased, promotion, store brand, store surface area, store competition, and consumer behavior measures. We find that when accounting for climate, only a subset of the product categories is sensitive to weather. Additionally, we show that climate can be approximated using a week index, eliminating the need for additional data collection and approximation efforts. Our findings have implications for both researchers and practitioners. Researchers should be aware of the importance of accounting for climate when studying the impact of weather on retail sales, as failing to do so may lead to erroneous conclusions. Practitioners can use our results to inform their marketing and sales strategies, taking into account the weather sensitivity of different product categories and the role of climate in shaping consumer behavior. Overall, our study emphasizes the need to consider climate when determining the impact of weather on retail sales, and provides practical insights for retailers and economist
La codétermination sera-t-elle la grande Réforme de notre siècle ?
No full textNational audienceOn connait la citation du général de Gaulle au sujet de la participation qui aurait dû être la grande réforme du siècle. La vision de la participation qu’il portait articulait trois formes de participation : la participation aux bénéfices, la participation au capital et la participation à la gestion. Il a pu mettre en œuvre de son vivant les deux premières formes de la participation au travers de dispositifs toujours en vigueur au 21ème siècle (la participation et l’intéressement). La troisième participation est en revanche longtemps restée à l’état de proposition dans les rapports qui préconisaient sa mise en œuvre depuis les années 1970. La prégnance des questions de développement durable et de responsabilité sociale de l’entreprise et l’émergence des sociétés à mission plaident en faveur d’une gouvernance élargie à toutes les parties prenantes de l’entreprise. Une quatrième participation est par ailleurs en train d’émerger alors même que la troisième n’a pas eu lieu
Purchasing team innovation climates as antecedents of purchasing involvement in open innovation
No full textInternational audienceThis study aims to enhance our understanding of the relationship between team innovation climate within the purchasing team and the level of purchasing involvement in open innovation initiatives. Previous research in psychology and management has documented the impact of team climate on innovation capacity. Furthermore, the purchasing function has been recognized as a bridge between internal and external resources in open innovation. However, to date, research has not examined the link between the team innovation climate and the role of the purchasing function in open innovation initiatives. To address this gap, we study a sample of 258 purchasing teams across industries in France based on a self-audit and questionnaire using established team innovation climate scales. From our analyses, four dimensions of the purchasing team climate towards innovation emerge: the team cohesiveness, the team creativity, the leader support for innovation, and the institutional support for innovation. We subsequently conduct regression and necessary condition analysis. Our results show that institutional support is both necessary and positively related to involvement. Moreover, purchasing’s ability to contribute to inbound open innovation is constrained by each of the four dimensions of the team innovation climate, to various extents. Our work thereby elucidates the individual elements and the collective impact of the team innovation climate that enable the exploitation of the innovative potential of suppliers through purchasing’s bridge function between external and internal innovation actors providing new insights into the human side of OI at team level
Energy Semantic Data Management and Utilization in Smart Grid Networks with Focus on Circular Economy
No full textInternational audienceFrom the first days of human beings’ existence on the Earth, energy has played an important and sensitive role in mitigating human needs. Nowadays, Energy is still a matter of debate and controversy among various societies independent of advanced or developing categories. Meanwhile, Smart Grid network with its special features and facilitating the process of production and distribution of renewable energy plays a crucial and historic role in improving the environmental status and climate change problems. This network can also be used as a key part in the circular economy model, which leads to economic, environmental, and social sustainability. One of the most basic steps in designing a Smart Grid network is semantic data structures and its management procedures. The data semantic models and how they are used to enable both integration and interoperability in energy Smart Grid highly influence the utilization of sources and planning the energy streams in the whole network. In a situation where this network is composed of different components such as power generation, transformation and transmission, distribution network, and consumption, a huge amount of data will be generated, which makes their interoperability a challenge. In addition, when the concept of smartness in energy Smart Grid networks is discussed, it is emphasized that there should be smart mechanisms to enable the seamless and reliable transfer of data and knowledge correctly through the network of stakeholders. This chapter has discussed the concepts of knowledge representation by focusing on Big Knowledge Graphs and how to represent knowledge with interoperability in energy Smart Grid networks. The focus will be put on the paradigm of smartness for establishing knowledge communication autonomously with circular economy considerations