Setting-up rules to characterize microsegregation

Characterization of chemical heterogeneities such as microsegregation resulting from solidification of metallic alloys is most often performed by EDS or WDS microanalysis with spot measurements located at corners of a regular grid. Rather than attempting a theoretical treatment of the statistics of such analyses, the quality of the procedure has been investigated by implementing “measurement” grids on numerical images that mimic solidification structures. Microstructures either with no geometrical constraints (uniform distribution of the solid nuclei) or with limited constraints that give some periodicity have been investigated. Systematic analysis of the effect of the location and size of the “measurement” grid enlightens the procedures which should be followed to minimize bias

Introduction générale

The population dynamics of small populations is attracting a lot of interest from conservation biologists. This can involve declining populations or on the other hand eruptions often related to human activities; reintroduction programmes are also concerned. In particular, attention should be drawn to the serious threats that certain eruptions represent to the biodiversity of the whole system. These questions also concern more theoretical studies in population biology. Notable progress has been made in this domain and it must be taken into account. The congress at Niederbronn attracted more fundamental contributions, which are presented here in abstract form, and contributions from practising conservation biologists which make up the majority of the present publicatio

Synthèse du colloque

Tout d’abord, un remerciement général pour les étudiants qui m’ont aidé dans la préparation de cette synthèse, en particulier j’ai une dette à l’égard de Didier QUINTARD et Armel GUILLET. Je demande votre indulgence sur plusieurs éléments avant cette intervention : d’une part, vous comprendrez aisément qu’ayant suivi les interventions au fur et à mesure j’ai pu commettre de temps en temps une erreur d’interprétation. Par ailleurs je ne pourrai pas signaler toutes les interventions. J’ai fait ..

Thoroughly analyzing the use of ring oscillators for on-chip hardware trojan detection

International audienceWith the globalization of the IC design flow, structural integrity verification to detect parasitic electrical activities has emerged as an important research domain for testing the genuineness of an Integrated Circuit (IC). Sensors like Ring Oscil-lators (RO) have been proposed to precisely monitor the internal behaviour of the ICs. In this paper we propose an experimental analysis of the impact of parasitic electrical activities on the frequencies of ROs and on the internal supply voltages measured. Our observations lead us to identify the limits of the usability of ROs for practical and embedded detection of Hardware Trojans

Maladie du hêtre. Bilan chiffré de la situation à l'été 2001

Durant l'été 2001, un inventaire des dégâts occasionnés par la maladie du hêtre à été réalisé. Les résultats de cette étude ont été publiés dans la revue Silva belgica. Nous en reprenons ici la conclusion ainsi que quelques-uns des nombreux graphiques et tableaux qui y sont présentés. Nous invitons le lecteur intéressé à se référer à l'article original

Extraction of intrinsic structure for Hardware Trojan detection

Cryptology ePrint Archive: Report 2015/912In this paper we present a novel solution to address the problem of potential malicious circuitry on FPGA. This method is based on an a technique of structure extraction which consider the infection of an all lot. This structure is related to the design (place and route, power grid...) of the integrated circuits which composes the lot. In case of additional circuitry this design will be modify and the extracted structure will be affected. After developing the extraction techniques we present a method- ology to insert detection of hardware trojan and counterfeit in different IC manufacturing steps. At last an application example using 30 FPGA boards validate our extraction method. Finally, statistical tools are then applied on the experimental results to distinguish a genuine lot from an infected one and confirm the potential of detection the extracted structure

Study of transformations and microstructural modification in Ti-LCB and T-555 alloys using Differential Scanning Calorimetry

peer reviewedThe aerospace industry is the single largest market for titanium products primarily due to the exceptional strength to weight ratio, elevated temperature performance and corrosion resistance. Titanium applications are most significant in jet engine and airframe components that are subject to high temperatures. The studied Ti-LCB and Ti-555 titanium alloys must present good properties to fatigue damage as they are located in a low-pressure compressor. In order to avoid this damage, an optimized alloy microstructure is required. In our case, the optimal microstructure would be a beta matrix in which small alpha particles are uniformly distributed, obtained after a combination of thermomechanical and thermal treatments. The understanding of the mechanisms ruling the microstructure evolution is achieved through the study of phase transformations versus temperature. During heating, the ωath phase is transformed into the ωiso phase, allowing itself the appearance of the α phase. Then this α phase is transformed progressively into the β phase, and the structure becomes totally β when the transus temperature is reached. Therefore, a thermal analysis tool such as DSC (Differential Scanning Calorimetry) was used in order to characterise the phase transformations of the material during imposed controlled temperature programs