Opinion groups formation and dynamics : structures that last from non lasting entities

We extend simple opinion models to obtain stable but continuously evolving communities. Our scope is to meet a challenge raised by sociologists of generating "structures that last from non lasting entities". We achieve this by introducing two kinds of noise on a standard opinion model. First, agents may interact with other agents even if their opinion difference is large. Second, agents randomly change their opinion at a constant rate. We show that for a large range of control parameters, our model yields stable and fluctuating polarized states, where the composition and mean opinion of the emerging groups is fluctuating over time

La légitimation de l'Union européenne par l'exportation de son modèle d'intégration et de gouvernance régionale. Le cas du Marché commun du sud (Note)

La structure internationale de l'après-guerre froide est confrontée à l'accélération de plusieurs dynamiques : celle de la globalisation et des intégrations régionales. En outre, la seule superpuissance à avoir survécu à la période du monde bipolaire sont les États-Unis. En ce qui concerne l'Union européenne, les années quatre-vingt-dix constituent un approfondissement de son architecture et un certain renforcement de son poids sur la scène internationale. Cette décennie va d'ailleurs voir l'engagement actif de l’UE dans l'appui au développement de nouvelles et anciennes intégrations régionales en pleine effervescence. Ce type de stratégie ne vise pas uniquement la conquête de nouveaux marchés pour les entreprises européennes, elle sert également à VUE pour se représenter davantage comme union politique vis-à-vis de ses partenaires extérieurs et renforcer sa légitimité dans un monde de plus en plus confronté à l’unipolarité et l'unilatéralisme américain. L’UE va dès lors chercher à se rapprocher de certains espaces régionaux en leur proposant un appui direct basé sur son expérience personnelle dans le domaine de l'intégration à l'instar du « partenariat stratégique » développé avec le Marché commun du sud (MERCOSUB). Ce type de partenariat renforce le projet international multirégiona-liste européen, qui consiste à réaménager le multilatéralisme en le faisant reposer sur des espaces d'intégration régionale ce qui, dans un tel scénario international devrait, aux yeux de VUE, lui conférer plus de légitimité du fait de son succès intégrationniste sui generis.The international structure of the post-cold-war era is confronted with an acceleration of several dynamics. One is globalization and the others are regional integrations. In addition, the only superpower to have survived the period of a bipolar world is the United States. With regard to the European Union, the 1990s saw a deepening of its architecture and a certain strengthening of its clout on the international stage. The decade also saw the active involvement of the EU in supporting the development of new and old regional integrations then fervently in progress. This type of strategy aims not only to conquer new markets for European businesses, but also to represent the EU more as a political union vis-à-vis its external partners and to strengthen its legitimacy in a world increasingly confronted with American unipolarity and unilateralism. The EU is hence seeking to draw closer to certain regional blocs and offer them direct support based on its personal experience in integration, as it has done in the "strategic partnership" developed with the Southern Common Market (MERCOSUR). This type of partnership strengthens Europe's project of international multiregionalism, which consists of revamping multilateralism along the lines of regionally integrated blocs. In the eyes of the EU, the advent of such an international scenario should bestow more legitimacy on the EU, given its success in integration sui generis

Demographic optimization of regions of interest for heart rate estimation through explainable remote photoplethysmography

Heart rate measurement can provide vital insights into the autonomic nervous system and cardiovascular health. Conventional heart rate monitoring devices include electrocardiogram and photoplethysmography, both of which involve equipping wearable devices to areas around the body. On the other hand, remote photoplethysmography is a non-contact heart rate measurement technology that estimates heart rate from facial video based on minuscule color changes due to blood flow. In some facial areas, referred to as regions of interest, the color change is more apparent, which leads to higher accuracy readings. Conventional regions of interest include areas such as the cheeks and forehead, although little to no research has been conducted regarding differences in regions of interest based on demographics. This thesis explores the notion of optimizing regions of interest based on demographics. Two models based on an existing state-of-the-art video vision transformer model architecture, the Physformer, are trained to estimate heart rate through remote photoplethysmography using the VIPL-HR dataset. The dataset participants are split into the demographic subsets "male" and "female." The models' attention outputs were used to create demographic-specific heatmaps. Findings show that the forehead and the area below the eyes may be prominent regions of interest for the male split, while the entire face and, to a larger degree, the cheeks are prominent regions of interest for the female split. Results indicate that there could be differences in optimal regions of interest with regard to demographics, although significantly more data is required to draw definitive conclusions

Mechanical Design of Triple Spoke cavity for Eurisol

International audienceWithin the framework of EURISOL programme, supported by European Union, IPN Orsay has proposed a 352 MHz triple Spoke superconducting cavity for the intermediate energy section beta 0.3 of high power proton linear accelerator. Triple Spoke cavity has a complicate geometry, 3D modeling with coupled electromagnetic and mechanic calculations were performed

Dynamic models of residential ségrégation: an analytical solution

We propose an analytical resolution of Schelling segregation model for a general class of utility functions. Using evolutionary game theory, we provide conditions under which a potential function, which characterizes the global configuration of the city and is maximized in the stationary state, exists. We use this potential function to analyze the outcome of the model for three utility functions corresponding to different degrees of preference for mixed neighborhoods. Schelling original utility function is shown to drive segregation at the expense of collective utility. If agents have a strict preference for mixed neighborhoods but still prefer being in the majority versus in the minority, the model converges to perfectly segregated configurations, which clearly diverge from the social optimum. Departing from earlier literature, these conclusions are based on analytical results. These results pave the way to the analysis of many structures of preferences, for instance those based on empirical findings concerning racial preferences. As a by-product, our analysis builds a bridge between Schelling model and the Duncan and Duncan segregation index.Residential segregation ; Schelling ; dynamic model ; potential function ; social preferences

Dynamic models of residential segregation: Brief review, analytical resolution and study of the introduction of coordination

In his 1971's Dynamic Models of Segregation paper, the economist Thomas C. Schelling showed that a small preference for one's neighbors to be of the same color could lead to total segregation, even if total segregation does not correspond to individual preferences and to a residential configuration maximizing the collective utility. The present work is aimed at deepening the understanding of the properties of dynamic models of segregation based on Schelling's hypotheses. Its main contributions are (i) to offer a comprehensive and up-to-date review of this family of models ; (ii) to provide an analytical solution to the most general form of this model under rather general assumptions ; to the best of our knowledge, such a solution did not exist so far ; (iii) to analyse the effect of two devices aimed at decreasing segregation in such a model. Chapter one summarizes the ingredients of Schelling's models. We show how the choices of the agent's utility function, of the neighborhood description and of the dynamical rule can impact the outcome of a model. Based on the observation of simulations' results, we find that the neighborhood description does not have a qualitative impact. As regards the dynamical rules, we show that the Logit Behavioral rule introduced in this literature by Young (1998) ; Zhang (2004b) presents several advantages relatively to the Best Response rule. Chapter two presents a general analytical solution to the model. To that aim, Schelling's model is recasted within the framework of evolutionary game theory, as previously done by Young (1998) ; Zhang (2004b). This allows to define sufficient assumptions regarding agents' utility functions that permit predicting the final state of the system starting from any configuration. This analytical resolution is then used to consider the outcomes of Schelling's utility function and of other utility functions previously used in this context. Chapter three examines the effects of introducing coordination in the moving decisions. This coordination is achieved through two different ways. We first impose different levels of taxes proportional to the externality generated by each move of the agents. It is shown that even a low level of tax is sufficient under certain circumstances to significantly reduce segregation. We then investigate the effect of the introduction of a local coordination by vote of co-proprietors, who are defined as the closest neighbors of each agent. It is shown that even a small amount of coordination can break segregation.segregation; Schelling; potential function; coordination; tax; vote

The Macroeconomic Implications of the New Banking Capital Regulation in Emerging Markets: A Duopoly Model Adapted to Risk-Averse Banks

In order to analyze the impact of the new banking capital regulation (Basel II) on the business cycle in an emerging economy, I develop a duopoly model composed of domestic and foreign banks. The principal results are: by the conduct of new banking capital regulation, the assessment of credit risk carried out by an international bank in a given country not only affects the total loans in that country but also the total assets supplied in other countries. Second, analyzing risk-averse banks, as portfolio diversification increases, the change in loans allocated in a given country by an international bank as a proportion of the original investment and the total level of loans for that country can be harshly affected by the behavior of a foreign bank following only “news” through the new capital regulation. Finally, even in the case that portfolio diversification increases without limits, the macroeconomic implication of a change of credit risk estimation, via the new capital regulation, is larger when banks are risk-neutral than risk-averse

The usual suspects: Investment Banks’ Recommendations and Emerging Markets

The paper addresses two core questions: do recommendations have an impact on the allocation of flows in the asset class? Above all, are we facing in this asset class major problems of asymmetries of information? In order to answer these questions, we used untapped and rich datasets. We constructed a unique database covering the period 1997-2006 for all the bond recommendations by the major Wall Street and City investment banks that dominate the emerging bond markets. The most important and relevant results are as follows. First, 90% of the underwriters recommend, at the announcement date of the issue, to buy or to maintain in their portfolio the bonds issued by the countries where they are acting as lead managers. Second, there is an additional bias, investment banks’ recommendations depend also on the relative size of the secondary bond market. In fact, there is a phenomenon that we call “too big to underwrite” meaning that investment banks do not send negative signals to investors of countries that, given their size, are considered important for their business. Finally, by using a simple cross-section analysis, we found that the impact of investment banks’ recommendations on capital flows is more significant and more predictable than some macroeconomic variables such as interest rates, economic growth and inflation

Solving an Air Conditioning System Problem in an Embodiment Design Context Using Constraint Satisfaction Techniques

International audienceIn this paper, the embodiment design of an air condition- ing system (ACS) in an aircraft is investigated using interval constraint satisfaction techniques. The detailed ACS model is quite complex to solve, since it contains many coupled variables and many constraints corresponding to complex physics phenomena. Some new heuristics and notions based on embodiment design knowledge, are briefly introduced to undertake some embodiment design concepts and to obtain a more relevant and more efficient solving process than classical algorithms. The benefits of using constraint programming in embodiment design are discussed and some difficulties for designers using CP tools are shortly detailed