129,951 research outputs found

    Binary Cepheids from optical interferometry

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    Classical Cepheid stars have been considered since more than a century as reliable tools to estimate distances in the universe thanks to their Period-Luminosity (P-L) relationship. Moreover, they are also powerful astrophysical laboratories, providing fundamental clues for studying the pulsation and evolution of intermediate-mass stars. When in binary systems, we can investigate the age and evolution of the Cepheid, estimate the mass and distance, and constrain theoretical models. However, most of the companions are located too close to the Cepheid (1-40 mas) to be spatially resolved with a 10-meter class telescope. The only way to spatially resolve such systems is to use long-baseline interferometry. Recently, we have started a unique and long-term interferometric program that aims at detecting and characterizing physical parameters of the Cepheid companions, with as main objectives the determination of accurate masses and geometric distances.Comment: 8 pages, Proceeding of the conference "Setting a new standard in the analysis of binary stars", September 2013, Leuven, Belgiu

    An Analysis Architecture for Communications in Multi-agent Systems

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    Evaluation tools are significant from the Agent Oriented Software Engineering (AOSE) point of view. Defective designs of communications in Multi-agent Systems (MAS) may overload one or several agents, causing a bullying effect on them. Bullying communications have avoidable consequences, as high response times and low quality of service (QoS). Architectures that perform evaluation functionality must include features to measure the bullying activity and QoS, but it is also recommendable that they have reusability and scalability features. Evaluation tools with these features can be applied to a wide range of MAS, while minimizing designer’s effort. This work describes the design of an architecture for communication analysis, and its evolution to a modular version, that can be applied to different types of MAS. Experimentation of both versions shows differences between its executions

    Design Within Complex Environments: Collaborative Engineering in the Aerospace Industry

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    The design and the industrialization of an aircraft, a major component, or an aerostructure is a complex process. An aircraft like the Airbus A400M is composed of about 700,000 parts (excluding standard parts). The parts are assembled into aerostructures and major components, which are designed and manufactured in several countries all over the world. The introduction of new Product Lifecycle Management (PLM) methodologies, procedures and tools, and the need to reduce time-to-market, led Airbus Military to pursue new working methods to deal with complexity. Collaborative Engineering promotes teamwork to develop product, processes and resources from the conceptual phase to the start of the serial production. This paper introduces the main concepts of Collaborative Engineering as a new methodology, procedures and tools to design and develop an aircraft, as Airbus Military is implementing. To make a Proof of Concept (PoC), a pilot project, CALIPSOneo, was launched to support the functional and industrial design process of a medium size aerostructure. The aim is to implement the industrial Digital Mock-Up (iDMU) concept and its exploitation to create shop fl oor documentation
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