Passive Covert Radars using CP-OFDM SFN. Reference signal recovery from blind beamforming

A passive Coherent Location (PCL) system uses the signal transmitted by so called illuminators-of-opportunity in the environment for the illumination of targets. It is then necessary to recover the original transmitted signal to be compared to the targets echoes. With CP-OFDM transmissions, it is quite easy to recover the original data and then to reconstruct the original transmission. But in the case of a Single Frequency Network , characterized by the presence of several transmitters using the same carrier frequency to broadcast the same signal, it is necessary to use directional sensors or spatial filter. In this paper, we propose two blind solutions : classical beamforming and CAPON filtering. Results of real measurements are presented

Hydroclimatic vulnerability of peat carbon in the central Congo Basin

The forested swamps of the central Congo Basin store approximately 30 billion metric tonnes of carbon in peat1,2. Little is known about the vulnerability of these carbon stocks. Here we investigate this vulnerability using peat cores from a large interfluvial basin in the Republic of the Congo and palaeoenvironmental methods. We find that peat accumulation began at least at 17,500 calibrated years before present (cal. yr BP; taken as AD 1950). Our data show that the peat that accumulated between around 7,500 to around 2,000 cal. yr BP is much more decomposed compared with older and younger peat. Hydrogen isotopes of plant waxes indicate a drying trend, starting at approximately 5,000 cal. yr BP and culminating at approximately 2,000 cal. yr BP, coeval with a decline in dominant swamp forest taxa. The data imply that the drying climate probably resulted in a regional drop in the water table, which triggered peat decomposition, including the loss of peat carbon accumulated prior to the onset of the drier conditions. After approximately 2,000 cal. yr BP, our data show that the drying trend ceased, hydrologic conditions stabilized and peat accumulation resumed. This reversible accumulation–loss–accumulation pattern is consistent with other peat cores across the region, indicating that the carbon stocks of the central Congo peatlands may lie close to a climatically driven drought threshold. Further research should quantify the combination of peatland threshold behaviour and droughts driven by anthropogenic carbon emissions that may trigger this positive carbon cycle feedback in the Earth system

Armed groups' modes of local engagement and post-conflict (in)stability: Insights from the Ethiopian and Somali civil wars

What distinguishes post-war governments that succeed in establishing a stable political order and prevent recurring conflict from those that do not? This comparative study considers the specific threats that typically lead to the collapse of the post-conflict political order to offer new hypotheses on the conditions that affect post-war governments' ability to sustainably restore stability. The threats considered include (i) fragmentation of the main actors in the conflict, (ii) inadequate demobilization, and (iii) enduring dependence of the post-war government on local brokers. Post-war regimes are more vulnerable to such risks after wars in which the dominant armed groups have established themselves by co-opting local power structures and drawing on existing socio-political networks, as this process redistributes power from the central to the local level. Empirically, this paper uses a novel dataset documenting the practices through which rebel groups may alter local power structures to highlight the connection between this wartime process of transformation and patterns of conflict recurrence. In addition, it contrasts the transition of the Tigray People's Liberation Front from rebellion to government in Ethiopia in the 1990s with the trajectory of the armed movements in Somalia that also overthrew the incumbent military regime but then failed to establish a viable state

Que faire en Indochine?

Gassier Maurice. Que faire en Indochine?. In: Politique étrangère, n°2 - 1947 - 12ᵉannée. pp. 133-154

« Si près si loin des entreprises. Du projet syndical aux pratiques de représentation des salariés et chefs de très petites entreprises »

International audienc

« De l’institutionnalisation de la participation syndicale à la matérialisation d’un ‘‘dialogue social régional’’. Ressorts et usages des dispositifs de gouvernance dans l’action publique »

International audienc

« Dynamique institutionnelle et mobilisation territoriale autour de la prévention dans les TPE »

International audienc

« Enjeux et limites d’une représentation collective dans les très petites entreprises (TPE) »

International audienc

Les arènes discrètes du paritarisme régional. Dispositifs, acteurs et pratiques du ‘‘dialogue social territorial’’

The reconfigurations of public action such as the decentralization of the politico-administrative system have led at the regional level to a multiplication of “territorial social dialogue” apparatuses which require the presence of employers’ organizations and workers unions. This new offer of institutional representation in the region influences employers and workers unions, both in their structure and their internal operating mode and from the point of view of the activities that their members have to carry out (discuss public policies, administer organizations providing public service missions). Based on an ethnographic survey that combines different qualitative methods (interviews, observations, documentary and archive analysis), the thesis aims to study the motives and effects of the process of institutionalization of employers’ organizations and workers unions, but also the modalities of their participation in the public action. On the one hand, it intends to grasp what the integration into the institutional spaces implies in terms of reorganizations for Unions and their spokespersons, by underlining in a new light a certain number of processes which are going through the militant universes, like the transformations of collective action registers and militant skills, their professionalization and the bureaucratization of organizations. On the other hand, it helps us to understand what is at stake and what actually happens in these poorly known institutional spaces, in particular the role of workers’ and employers’ unions in local public action. At the crossroads of the sociology of industrial relations, unionism and public action, this work will bring us to better understand what the decentralization policies of the French State and the changes in the methods of manufacturing territorial policies do to the way in which the union and employer representation at the local level are being reconfigured. In this sense, this work intends to contribute to the analysis of the transformations of the French industrial relations system and its relations with the political field.Les reconfigurations de l’action publique telles que la décentralisation du système politico-administratif ont entraîné à l’échelle régionale une multiplication de dispositifs de « dialogue social territorial » qui sollicitent la présence de représentants syndicaux et patronaux. Cette nouvelle offre de représentation institutionnelle en région affecte les organisations syndicales et patronales, tant dans leur mode de structuration et de fonctionnement internes que du point de vue des activités que leurs membres sont amenés à réaliser (discuter des politiques publiques, administrer des organismes paritaires). À partir d’une enquête ethnographique qui combine différentes méthodes qualitatives (entretiens, observations, analyse documentaire et d’archives), la thèse se propose d’étudier les ressorts et les effets du processus d’institutionnalisation de l’action syndicale et patronale, mais aussi les modalités de leur participation à l’action publique. D’un côté, elle entend saisir ce que l’intégration dans les dispositifs de l’action publique locale implique comme ajustements pour les syndicats et leurs porte-parole, en éclairant sous un nouveau jour certains processus qui traversent les univers militants : les transformations des répertoires d’action collective et des compétences militantes, leur professionnalisation et la bureaucratisation des organisations. De l’autre, elle nous aide à comprendre ce qui se joue et ce qui se fait au concret dans ces espaces institutionnels peu connus, notamment le rôle des syndicats de salariés et patronaux dans l’action publique locale. À la croisée de la sociologie des relations professionnelles, du syndicalisme et de l’action publique, ce travail nous amènera à mieux comprendre ce que les politiques de décentralisation de l’État français et les transformations des modes de fabrication des politiques territoriales font à la manière dont se reconfigurent les modalités de la représentation syndicale et patronale à l’échelle locale. En ce sens, ce travail entend contribuer à l’analyse des recompositions du système de relations professionnelles français et de ses relations au champ politique