Défaillances au sein de réseaux interdépendants : les défis de la mise en place d’un système d’alerte précoce

RÉSUMÉ Le fonctionnement adéquat de nos sociétés repose sur la fourniture d’un certain nombre de ressources au travers des réseaux qui les supportent. Ces ressources sont fournies à la société en général mais également à d’autres réseaux en ayant besoin pour fonctionner. Typiquement, le réseau d’eau nécessite de l’électricité pour alimenter ses pompes, alors que le réseau électrique a besoin d’eau pour le refroidissement de certains équipements de production d’électricité. De telles relations de type client/fournisseur créent des interdépendances entre certains de ces réseaux. Parmi ceux-ci, ceux dont l’interruption de service aurait des conséquences sérieuses sur le fonctionnement de notre société sont catégorisés dans les infrastructures essentielles. La fourniture adéquate de leur ressource est une préoccupation majeure et constante des opérateurs d’infrastructures essentielles. À ce titre, ils estiment devoir être capable de connaître les effets d’une défaillance initiale sur leur propre réseau ainsi que sur ceux avec lesquels il serait interconnecté. Modéliser cette propagation des défaillances dans l’espace et dans le temps, et fournir cette information au sein d’une interface conviviale leur permettrait de disposer d’un préavis utile à la mise en place de mesures de gestion destinées à limiter les conséquences d’une défaillance. Le développement d’un système d’alerte précoce s’inscrit dans cette perspective. Les travaux de recherche présentés dans l’article en annexe ainsi que dans ce mémoire qui en détaille chacun des aspects, ont trait au développement d’un tel système en vue d’une implantation et validation à Montréal, à la fois dans sa définition, son contenu, et dans une maquette d’outil. Or, le développement du système a rencontré un certain nombre de difficultés et n’a pu être mené jusqu’à son terme. En revanche, l’examen de ses difficultés a permis d’approfondir l’analyse de la composition du système, de proposer un certain nombre de pistes permettant de contourner les obstacles rencontrés et de continuer néanmoins à utiliser ce système au travers d’autres applications, jusqu’à ce qu’une nouvelle implantation puisse être tentée.----------ABSTRACT The proper functioning of our societies lies on a certain number of key resources provided through supporting networks. These resources are provided not only to the society in general but also to other networks which use the resources the others produce. Typically, the pumps operating the water network need electricity to work, as well as the electrical network needs water to cool down certain production equipments to maintain a normal operating temperature. Such customer/supplier relationships generate interdependencies between some of these networks. Among them, some are categorized as critical infrastructures, which failure would have debilitating effects on our society. The proper supplying of their resources is a major and permanent concern for critical infrastructure operators. As such, they consider they need to be informed of the consequences of an initial failure on their own network as well as on the ones it is interconnected with. Being able to model such propagation in space and time, and provide this information through a user-friendly interface would give operators a certain period of time within which they could take appropriate measures to mitigate the consequences. An early warning system is to be developed in this perspective. The research presented in the article in annex as well as in this dissertation which details each of its aspects is related to the development of such a system, both in its definition, constitution and as a tool model supposed to be implemented and tested in Montreal. Thus, the development of this system faced several difficulties and could not be brought to fruition. Nevertheless, the investigation of the obstacles led to a better understanding of the constitution of the system, allowed to suggest a certain number of approaches in order to overcome them and yet to keep using the system through various applications, until a new implementation could be considered

Analysis of Air Traffic Controllers Decisions

International audienceThis paper presents an approach based on a multiple criteria decision making methodology (MCDM) to analyse the decisions of Air Traffic Controllers. This study will allow to model some tools able to assist the controllers in their tasks and particularly able to help them to assume the ceaseless increase of Air Traffic. Currently the platform AMANDA assists controllers on only one sector of control. This platform was very pleasant welcome, and we wish to extend these principles to adjacent sectors, and thus include tool to help the cooperation between adjacent controllers. This analysis is composed of three main points. First it is necessary to determine the decision making process of controllers. The second point consists of the application of the MCDM which guide all the study. And finally a repertory grid technique is applied in order to support the operational aspect of MCDM and to support the interviews. We begin this paper by a presentation of Air traffic Control and the problematic, we present then AMANDA and its principles, and the objectives for the new version. In a third part we describe the approach developed and a real example of its application, the results and analyses that we can deduce of this first grid are also presented. These results must be, of course, confirmed and validated by the controllers

AMANDA V3: Toward a Common Workspace between Air Traffic Controllers

International audienceThis paper presents the different tools developed in the LAMIH, in optics to assist air traffic controllers in their tasks, to decrease their workloads, and to enable them to support the ceaseless increase of the traffic. Common philosophy to all these tools is to preserve the controllers in the loop: we do not try to develop tools entirely automatic. The platform AMANDA V2 made it possible to set up and to evaluate a common workspace, which allows the two controllers of a sector to cooperate and to share the same representation of their traffic and conflicts. This space maintains common situation awareness. This tool was very appreciated by professional controllers and we now wish to extend this principle to the cooperation between two planning controllers of two adjacent sectors. It is what we present in this paper which begins with a presentation of the ATC then a point on the platforms of the laboratory and particularly AMANDA V2, to conclude with the objectives of AMANDA V3

Choice, sorting and ranking in aerial conflict management

International audienceIn the Air Traffic control, many decisions must be taken, quickly. Due to the increase of traffic, these decisions are more and more numerous. It is possible to propose some assistance tools to air traffic controllers in order to help them to make decisions. For that purpose we need to understand how the controllers make these decisions. This paper proposes a knowledge acquisition approach composed of three steps: an analysis of the decision-making process, a multiple criteria methodology, and interviews in order to obtain information, and to develop models. The last part of this paper presents the results we expect to obtain with appropriate interviews and analyse

Effects of snow grain shape on climate simulations : sensitivity tests with the Norwegian Earth System Model

Snow consists of non-spherical grains of various shapes and sizes. Still, in radiative transfer calculations, snow grains are often treated as spherical. This also applies to the computation of snow albedo in the Snow, Ice, and Aerosol Radiation (SNICAR) model and in the Los Alamos sea ice model, version 4 (CICE4), both of which are employed in the Community Earth System Model and in the Norwegian Earth System Model (NorESM). In this study, we evaluate the effect of snow grain shape on climate simulated by NorESM in a slab ocean configuration of the model. An experiment with spherical snow grains (SPH) is compared with another (NONSPH) in which the snow shortwave single-scattering properties are based on a combination of three non-spherical snow grain shapes optimized using measurements of angular scattering by blowing snow. The key difference between these treatments is that the asymmetry parameter is smaller in the non-spherical case (0.77-0.78 in the visible region) than in the spherical case (similar to 0.89). Therefore, for the same effective snow grain size (or equivalently, the same specific projected area), the snow broadband albedo is higher when assuming non-spherical rather than spherical snow grains, typically by 0.02-0.03. Considering the spherical case as the baseline, this results in an instantaneous negative change in net shortwave radiation with a global-mean top-of-the-model value of ca. -0.22Wm(-2). Although this global-mean radiative effect is rather modest, the impacts on the climate simulated by NorESM are substantial. The global annual-mean 2m air temperature in NONSPH is 1.17K lower than in SPH, with substantially larger differences at high latitudes. The climatic response is amplified by strong snow and sea ice feedbacks. It is further demonstrated that the effect of snow grain shape could be largely offset by adjusting the snow grain size. When assuming non-spherical snow grains with the parameterized grain size increased by ca. 70 %, the climatic differences to the SPH experiment become very small. Finally, the impact of assumed snow grain shape on the radiative effects of absorbing aerosols in snow is discussed.Peer reviewe

Knowledge Acquisition for the Creation of Assistance Tools to the Management of Air Traffic Control

International audienceThis paper presents an approach which has for objective to model new tools allowing to help the controllers to assume the incessant increase of the air traffic (actual version of the platform AMANDA V2), as well as help them in the negotiation phase and cooperation with their counterparts of adjacent sector (objectives of the new version of AMANDA). Help them in furnishing some tools able to quickly share information, and to maintain good common situation awareness. An approach is proposed, it is divided in three main phases. A first phase which consists of understand and to model the decision-making process of controllers. The second phase introduces a multiple criteria decision-making methodology. This Methodology has for objective to understand in more details the activities of controllers and the cases of cooperation with adjacent sectors. Finally, the last phase is the operational level of the approach, and consists of an application of repertory grid methodology in order to guide the interviews with the different participants of the study. This will allow realizing the knowledge acquisition, keeping in mind objective to develop new tools. To conclude this paper, the last part presents an example of application of this approach and the first results

The transcription factor Kruppel homolog 1 is linked to the juvenile hormone-dependent maturation of sexual behavior in the male moth, Agrotis ipsilon

In the male moth, Agrotis ipsilon, the behavioral response and neuronal sensitivity in the primary olfactory center, the antennal lobe (AL), to sex pheromone increase with age and juvenile hormone (JH) biosynthesis. Although JH has been shown to control this age-dependent plasticity, the underlying signaling pathway remains obscure. In this context, we cloned a full cDNA encoding the Kruppel homolog 1 transcription factor (AipsKr-h1) of A. ipsilon, which was found to be predominantly expressed in ALs, where its amount increased concomitantly with age and sex pheromone responses. Conversely, the expression of AipsKr-h1 protein in the antenna was age-independent. Moreover, the administration of JH in immature males or fluvastatin, an inhibitor of JH biosynthesis, in mature males induced an increase or a decline of the AipsKr-h1 protein level in ALs, respectively. This effect was suppressed with a combined injection of fluvastatin and JH. Our results showed that Aipskr-h1 is a JH-upregulated gene that might mediate JH action on central pheromone processing, modulating sexual behavior in A. ipsilon

Steroid hormone signaling is involved in the age-dependent behavioral response to sex pheromone in the adult male moth Agrotis ipsilon

In most animals, including insects, male reproduction depends on the detection and processing of female-produced sex pheromones. In the male moth, Agrotis ipsilon, both behavioral response and neuronal sensitivity in the primary olfactory center, the antennal lobe (AL), to female sex pheromone are age- and hormone-dependent. In many animal species, steroids are known to act at the brain level to modulate the responsiveness to sexually relevant chemical cues. We aimed to address the hypothesis that the steroidal system and in particular 20-hydroxyecdysone (20E), the main insect steroid hormone, might also be involved in this olfactory plasticity. Therefore, we first cloned the nuclear ecdysteroid receptor EcR (AipsEcR) and its partner Ultraspiracle (AipsUSP) of A. ipsilon, the expression of which increased concomitantly with age in ALs. Injection of 20E into young sexually immature males led to an increase in both responsiveness to sex pheromone and amount of AipsEcR and AipsUSP in their ALs. Conversely, the behavioral response decreased in older, sexually mature males after injection of cucurbitacin B (CurB), an antagonist of the 20E/EcR/USP complex. Also, the amount of AipsEcR and AipsUSP significantly declined after treatment with CurB. These results suggest that 20E is involved in the expression of sexual behavior via the EcR/USP signaling pathway, probably acting on central pheromone processing in A. ipsilon

Involvement of the G-protein-coupled dopamine/ecdysteroid receptor DopEcR in the behavioral response to sex pheromone in an insect

Most animals including insects rely on olfaction to find their mating partners. In moths, males are attracted by female-produced sex pheromones inducing stereotyped sexual behavior. The behaviorally relevant olfactory information is processed in the primary olfactory centre, the antennal lobe (AL). Evidence is now accumulating that modulation of sex-linked behavioral output occurs through neuronal plasticity via the action of hormones and/or catecholamines. A G-protein-coupled receptor (GPCR) binding to 20-hydroxyecdysone, the main insect steroid hormone, and dopamine, has been identified in Drosophila (DmDopEcR), and was suggested to modulate neuronal signaling. In the male moth Agrotis ipsilon, the behavioral and central nervous responses to pheromone are age-dependent. To further unveil the mechanisms of this olfactory plasticity, we searched for DopEcR and tested its potential role in the behavioral response to sex pheromone in A. ipsilon males. Our results show that A. ipsilon DopEcR (named AipsDopEcR) is predominantly expressed in the nervous system. The corresponding protein was detected immunohistochemically in the ALs and higher brain centers including the mushroom bodies. Moreover, AipsDopEcR expression increased with age. Using a strategy of RNA interference, we also show that silencing of AipsDopEcR inhibited the behavioral response to sex pheromone in wind tunnel experiments. Altogether our results indicate that this GPCR is involved in the expression of sexual behavior in the male moth, probably by modulating the central nervous processing of sex pheromone through the action of one or both of its ligands