Hybridation of Bayesian networks and evolutionary algorithms for multi-objective optimization in an integrated product design and project management context

A better integration of preliminary product design and project management processes at early steps of system design is nowadays a key industrial issue. Therefore, the aim is to make firms evolve from classical sequential approach (first product design the project design and management) to new integrated approaches. In this paper, a model for integrated product/project optimization is first proposed which allows taking into account simultaneously decisions coming from the product and project managers. However, the resulting model has an important underlying complexity, and a multi-objective optimization technique is required to provide managers with appropriate scenarios in a reasonable amount of time. The proposed approach is based on an original evolutionary algorithm called evolutionary algorithm oriented by knowledge (EAOK). This algorithm is based on the interaction between an adapted evolutionary algorithm and a model of knowledge (MoK) used for giving relevant orientations during the search process. The evolutionary operators of the EA are modified in order to take into account these orientations. The MoK is based on the Bayesian Network formalism and is built both from expert knowledge and from individuals generated by the EA. A learning process permits to update probabilities of the BN from a set of selected individuals. At each cycle of the EA, probabilities contained into the MoK are used to give some bias to the new evolutionary operators. This method ensures both a faster and effective optimization, but it also provides the decision maker with a graphic and interactive model of knowledge linked to the studied project. An experimental platform has been developed to experiment the algorithm and a large campaign of tests permits to compare different strategies as well as the benefits of this novel approach in comparison with a classical EA

Origin of Second Harmonic Generation from individual Silicon Nanowires

We investigate Second Harmonic Generation from individual silicon nanowires and study the influence of resonant optical modes on the far-field nonlinear emission. We find that the polarization of the Second Harmonic has a size-dependent behavior and explain this phenomenon by a combination of different surface and bulk nonlinear susceptibility contributions. We show that the Second Harmonic Generation has an entirely different origin, depending on whether the incident illumination is polarized parallel or perpendicularly to the nanowire axis. The results open perspectives for further geometry-based studies on the origin of Second Harmonic Generation in nanostructures of high-index centrosymmetric semiconductors.Comment: 7 Pages, 4 Figures + 3 Pages, 6 Figures in Appendi

Prions of Ruminants Show Distinct Splenotropisms in an Ovine Transgenic Mouse Model

Background: Transmissible agents involved in prion diseases differ in their capacities to target different regions of the central nervous system and lymphoid tissues, which are also host-dependent. Methodology/Principal Findings: Protease-resistant prion protein (PrP res) was analysed by Western blot in the spleen of transgenic mice (TgOvPrP4) that express the ovine prion protein under the control of the neuron-specific enolase promoter, after infection by intra-cerebral route with a variety of transmissible spongiform encephalopathies (TSEs) from cattle and small ruminants. Splenic PrP res was consistently detected in classical BSE and in most natural scrapie sources, the electrophoretic pattern showing similar features to that of cerebral PrP res. However splenic PrP res was not detected in L-type BSE and TME-in-cattle, or in the CH1641 experimental scrapie isolate, indicating that some TSE strains showed reduced splenotropism in the ovine transgenic mice. In contrast with CH1641, PrP res was also consistently detected in the spleen of mice infected with six natural ‘‘CH1641-like’ ’ scrapie isolates, but then showed clearly different molecular features from those identified in the brains (unglycosylated PrP res at,18 kDa with removal of the 12B2 epitope) of ovine transgenic mice or of sheep. These features included different cleavage of the main PrP res cleavage product (unglycosylated PrP res at,19 kDa with preservation of the 12B2 epitope) and absence of the additional C-terminally cleaved PrP res product (unglycosylated form at,14 kDa) that was detected in the brain. Conclusion/Significance: Studies in a transgenic mouse model expressing the sheep prion protein revealed differen

Is the presence of abnormal prion protein in the renal glomeruli of feline species presenting with FSE authentic?

In a recent paper written by Hilbe et al (BMC vet res, 2009), the nature and specificity of the prion protein deposition in the kidney of feline species affected with feline spongiform encephalopathy (FSE) were clearly considered doubtful. This article was brought to our attention because we published several years ago an immunodetection of abnormal prion protein in the kidney of a cheetah affected with FSE. At this time we were convinced of its specificity but without having all the possibilities to demonstrate it. As previously published by another group, the presence of abnormal prion protein in some renal glomeruli in domestic cats affected with FSE is indeed generally considered as doubtful mainly because of low intensity detected in this organ and because control kidneys from safe animals present also a weak prion immunolabelling. Here we come back on these studies and thought it would be helpful to relay our last data to the readers of BMC Vet res for future reference on this subject

Nanocristaux pour les mémoires flash (multicouches, métalliques et organisés)

Les deux principales limitations des mémoires non-volatiles de type Flash à stockage de charges dans des nanocristaux en silicium sont la faible fenêtre mémoire et la dispersion des caractéristiques électriques due à la dispersion en taille des nanocristaux. Dans cette thèse, plusieurs solutions sont étudiées afin de remédier à ces deux défauts. Afin d'augmenter la fenêtre de programmation, une première approche consiste à augmenter la densité de stockage de charges grâce à l'utilisation d'une double couche de nanocristaux en silicium. Le fonctionnement et les performances électriques de ces dispositifs mémoires sont étudiés puis interprétés grâce à un modèle analytique. Une seconde approche, plus amont, consiste à utiliser des nanocristaux métalliques pour augmenter la quantité de charges piégées dans les nanocristaux. Le dépôt, la passivation et l'intégration de nanocristaux à caractère métallique (Pt, TiN, W) en tant que grille flottante dans un dispositif mémoire sont ainsi réalisés. Enfin, l'organisation bottom-up des nanocristaux est proposée comme une solution à la dispersion des caractéristiques électriques des dispositifs mémoires. Un procédé original de transfert et de gravure d'un masque auto-organisé à base de copolymères diblocs est développé.The two main limitations of Flash nonvolatile memories charge storage in silicon nanocrystals are the small memory window and the dispersion of electrical characteristics due to the size dispersion of nanocrystals. In this thesis, several solutions are studied in order to remedy these defects. In order to increase the programming window, a first approach is to increase the density of charges stored in the device through the use of a double layer of silicon nanocrystals. The operation and electrical performance of these memory devices are studied and interpreted through an analytical model. A second approach, more upstream, is the use of metallic nanocrystals to increase the amount of trapped charges in the nanocrystals. Deposition, passivation and integration of metal nanocrystals (Pt, TiN, W) as a floating gate in a memory device have been realized. Finally, the "bottom-up" organisation of nanocrystals is proposed as a solution to the dispersion of electrical characteristics of memory devices. An original process for transferring a self-organized diblock copolymer mask into a hard mask is developed and used to etch nanocrystals with small size dispersion.SAVOIE-SCD - Bib.électronique (730659901) / SudocGRENOBLE1/INP-Bib.électronique (384210012) / SudocGRENOBLE2/3-Bib.électronique (384219901) / SudocSudocFranceF

Phenotypic diversity revealed in cattle prion diseases

Up until now, Bovine Spongiform Encephalopathy (BSE) was thought to be caused by just one pathogen, which explained the highly uniform features of the disease in cattle. Unexpectedly, among cattle diagnosed with BSE in France, we found six cases where the disease marker, i.e. the prion protein, had molecular features clearly distinct from those typically found in BSE. Furthermore, two other cases were recently identified in Italy, with features different both from typical BSE and from these six atypical cases in France. Histopathological features in these two Italian cases also strongly suggested that the disease affecting these animals might not have been BSE. Hypotheses on the origin of such atypical cases are being discussed.On considérait jusqu'alors que l'encéphalopathie spongiforme bovine (ESB) était liée à l'infection par un agent infectieux unique, expliquant les caractéristiques très uniformes de la maladie chez les bovins. De façon inattendue, nous avons rencontré en France six cas, parmi des bovins diagnostiqués comme atteints d'ESB, qui présentent des caractéristiques moléculaires de la protéine prion pathologique, marqueur de l'infection, tout à fait différentes de celles habituellement rencontrées dans l'ESB. Deux cas présentant des caractéristiques différentes, aussi bien de l'ESB typique que des 6 cas précédents, ont par ailleurs été identifiés récemment en Italie. Les éléments de caractérisation histopathologique de ces deux derniers cas suggèrent par ailleurs très fortement qu'il s'agit d'une maladie différente de l'ESB. Les hypothèses concernant l'origine de ces cas atypiques sont discutées

Transmission of New Bovine Prion to Mice

We previously reported that cattle were affected by a prion disorder that differed from bovine spongiform encephalopathy (BSE) by showing distinct molecular features of disease-associated protease-resistant prion protein (PrPres). We show that intracerebral injection of such isolates into C57BL/6 mice produces a disease with preservation of PrPres molecular features distinct from BSE

L-Type Bovine Spongiform Encephalopathy in Genetically Susceptible and Resistant Sheep: Changes in Prion Strain or Phenotypic Plasticity of the Disease-Associated Prion Protein?

Background. Sheep with prion protein (PrP) gene polymorphisms QQ171 and RQ171 were shown to be susceptible to the prion causing L-type bovine spongiform encephalopathy (L-BSE), although RQ171 sheep specifically propagated a distinctive prion molecular phenotype in their brains, characterized by a high molecular mass proteaseresistant PrP fragment (HMM PrPres), distinct from L-BSE in QQ171 sheep. Methods. The resulting infectious and biological properties of QQ171 and RQ171 ovine L-BSE prions were investigated in transgenic mice expressing either bovine or ovine PrP. Results. In both mouse lines, ovine L-BSE transmitted similarly to cattle-derived L-BSE, with respect to survival periods, histopathology, and biochemical features of PrPres in the brain, as well as splenotropism, clearly differing from ovine classic BSE or from scrapie strain CH1641. Nevertheless and unexpectedly, HMM PrPres was found in the spleen of ovine PrP transgenic mice infected with L-BSE from RQ171 sheep at first passage, reminiscent, in lymphoid tissues only, of the distinct PrPres features found in RQ171 sheep brains. Conclusions. The L-BSE agent differs from both ovine classic BSE or CH1641 scrapie maintaining its specific strain properties after passage in sheep, although striking PrPres molecular changes could be found in RQ171 sheep and in the spleen of ovine PrP transgenic mice