Altran

About: Altran is a company organization based out in Neuilly-sur-Seine, France. It is known for research contribution in the topics: Software development & Formal verification. The organization has 488 authors who have published 512 publications receiving 6395 citations.

Statistical performance comparison between the FSV and the FS-NMI index

Abstract: This paper presents a performance comparison between two validation methods developed specifically for the Computational Electromagnetics purposes: the Feature Selective Validation (FSV) and the Feature Selective Normalized Mutual Information (FSNMI) index. To achieve this goal, a statistical analysis of 40 different cases of study (pairs of data sets) is carried out covering a wide range of real-life applications, such as, frequency domain, noisy and transient data, among others. The results provided an insight of the relationships between each method, showing that more effort is required to achieve generally coherent validation results between the FSV and the FSNMI.

From Research to Innovation, How to Create Value for an IT Consulting and Engineering Service Firm through its Internal Research Activities

Abstract: IT consulting and engineering firms generally develop strategic knowledge for their clients based on their own competences in various business methods and processes. Knowledge and competences can be improved through collaborative research projects and further leveraged for their own strategic development. The aim of this paper is to build and experiment an organizational management tool within a consulting firm. The tool allows the creation of value and differentiation levers on the competitive market of research and innovation consultancy and illustrates how to benefit from internal research activities that can be viewed as intangible resources. In light of competence-based theory this work shows how strategic knowledge developed on an emerging field such as e-health can be rearranged into strategic processes in order to inspire a proactive strategic vision within a consulting firm.

Evaluation of Direct Printed Heat Sinks on Metallized Ceramic Substrate for High-Performance Power Modules

Abstract: In this article, we propose a new packaging technology enabling the development of a high-performance power module for harsh environments. This approach is based on the use of the selective laser melting (SLM) technique in order to directly print metal heat sinks on the backside of the metallized substrate. In order to explore the viability of this method, the assembled parts were evaluated thoroughly after the manufacturing process. Moreover, their robustness was assessed during aging under harsh conditions. Results show that the ultimate tensile strength and yield strength of the printed alloy are higher than the casted AlSi7Mg0.6 counterpart. The interfaces between the printed alloy and the substrate Al metal layer do not show any weaknesses, and shear stress values are higher than 100 MPa. For all heat sink patterns, the substrate warpage is reduced during thermal cycling due to the Al alloy creeping, while the highly curved substrates show cracks in the ceramic after 400 cycles. Accordingly, direct printing of heat sink with patterns based on fins array reveals a promising path for high-reliability, high-performance power module packaging.

3MI OPD optical design: concept and performances

Abstract: The Multi-Viewing, Multi-Channel, Multi-Polarisation Imager (3MI) is an imaging radiometer for the ESA/Eumetsat MetOp-SG programme. Based on the heritage of POLDER/PARASOL, 3MI will collect global observations of the top-of-atmosphere polarised bi-directional reflectance distribution function in 12 spectral bands, by observing the same target from multiple views using a push-broom scanning concept. In order to mitigate any technological risks associated with the 3MI instrument development, an Elegant Breadboard of representative form, function and performance to the 3MI VNIR lens was foreseen in the frame of the Optics Pre- Development (OPD) activity. The optical design and the performance results of the OPD VNIR lens are presented, from the top level requirements flow-down to the optical design solution and concept adopted. The large FOV and image irradiance uniformity, the extended VNIR spectral range, combined with the demanding polarisation and stray-light requirements are the main design drivers. The design concept is based on a Galilean telescope coupled to a focusing group. The aperture stop, placed in between, is located in such a way that the system is telecentric in image space. The system exhibits a fine control of the entrance pupil size as a function of the FOV, low distortion and correction of lateral chromatic aberration. Polarisation related performances are achieved by low polarisation sensitivity and low retardance anti-reflection coatings, as well as by a proper selection of glass material properties.

Numerical and experimental study of the drilling of multi-stacks made of titanium alloy Ti-6Al-4V: interface and burr behavior

Abstract: Machining and especially drilling of multi-stacks is a challenge task. In fact, drilling of multi-layers generates several damages such as burr at the hole exit and the decohesion of the interface of the layers. It is important to note that the decohesion phenomenon favors the accumulation of the chips at the interface of the layers. In this case, it will not be possible to use the automated system (such as robots) for drilling and fastening in the aeronautical field. This work gives focuses on the numerical and an experimental study during drilling of a multi-stack made of titanium alloy (Ti/Ti), which is usually encountered during the assembly of the aircraft door at Boeing Company. The impact of the machining parameters on the thrust force, responsible of the decohesion of the layers as well as the burr size, has been investigated experimentally and numerically. The proposed model is based on the behavior law of Johnson-Cook for the titanium parts and the cohesive zone for the interface. The main experimental and numerical results have shown that the feed rate and the thickness of the bottom layer have a great influence on the size of the decohesion zone. However, the burr at the hole exit is strongly influenced by the feed rate.