Estimating the Template in the Total Space with the Fréchet Mean on Quotient Spaces may have a Bias: a Case Study on Vector Spaces Quotiented by the Group of Translations

International audienceWhen we have a deformation group acting on a vector space of observations, these data are not anymore elements of our space but rather orbits for the group action we consider. If the data are generated from an unknown template with noise, to estimate this template, one may want to minimize the variance in the quotient set. In this article we study statistics on a particular quotient space. We prove that the expected value of a random variable in our vector space mapped in the quotient space is different from the Fréchet mean in the quotient space when the observations are noisy

Histologic evaluation of bone healing of adjacent alveolar sockets grafted with bovine- and porcine-derived bone: a comparative case report in humans

To evaluate and compare histomorphometrically the bone response to two xenografts, one bovine and the other porcine, grafted in adjacent extraction sockets in a human. In this case report, two adjacent maxillary premolars were extracted, and the sockets were filled with two different xenogeneic bone substitutes (first premolar with bovine bone, and second premolar with porcine bone) to counteract post-extraction volume loss. Following 6 months bone core specimens were harvested during the placement of implants at the regenerated sites. Histomorphometrically, for the bovine xenograft the percentage of newly formed bone (osteoid) was 26.85%, the percentage of the residual graft material was 17.2% and the percentage of connective tissue 48.73%, while for the porcine xenograft, newly formed bone (osteoid) represented 32.19%, residual graft material was 6.57% and non-mineralized connective tissue was 52.99%. Histological results indicated that both biomaterials assessed in this study as grafts for socket preservation technique are biocompatible and osteoconductive. Bovine bone derived demonstrated to be less resorbable than porcine bone derived. Both xenogenic biomaterials did not interfere with the normal bone reparative processe

Simulation numérique de la condensation / évaporation et de la coagulation des nanoparticules

National audienceAware of the risks related to nanoparticles (particles which present at least one dimension less than 100 nanometers), INERIS decided in 2009 to create a research program in order to develop a model that would be able to simulate the dynamic of nanoparticles in both confined and free atmospheres. The distinction with usual models is that we need to follow the evolution of the number of particles together with their the mass : in order to simulate the evolution of nanoparticles, the number is much more relevant. A comparative review of algorithms currently used in air quality models and new algorithms adapted to nanoparticles is presented. This first study addresses condensational growth, evaporation and coagulation. The model is to be integrated in chemistry-transport models (CHIMERE) and in CFD models (code_Saturne EdF).Conscient des risques liés aux nanoparticules (particules dont au moins une des dimensions est inférieure à 100 nanomètres), l'INERIS(1) a engagé en 2009 un programme de recherche en collaboration avec le CEREA(2) afin de développer un modèle capable de simuler les transformations des nanoparticules dans les ambiances intérieures (espaces confinés) comme dans l'atmosphère. En effet, les nanoparticules sont notamment susceptibles de coaguler, de grossir par condensation, et de se déposer sur les parois; ce qui modifie leur granulométrie. Une des problématiques liée à la modélisation des nanoparticules est que leur nombre est déterminant devant leur masse, tout au contraire des particules étudiées jusqu'à présent (particules fines ou grossières dont une des dimensions est supérieure à 100 nanomètre). Différents schémas numériques ont été développés pour simuler la condensation/évaporation d'une population de particules, et un noyau de coagulation issu d'algorithmes usuels a été intégré. L'inter-comparaison de ces schémas met en évidence que certains sont plus adaptés que d'autres pour les nanoparticules. Les algorithmes qui sont appropriés pour toutes les tailles de particules sont présentés. A terme, ce modèle de dynamique des nanoparticules a vocation à être intégré dans des modèles de dispersion atmosphérique (CHIMERE) et des modèles CFD (code_Saturne EdF

Characterisation of aged HDPE pipes from drinking water distribution : investigation of crack depth by Nol ring tests under creep loading

International audienceHDPE pipes are used for the transport of drinking water. However, disinfectants in waterseem to have a strong impact on their mechanical behaviour, limiting their lifetime inoperation. Indeed, oxidation occurs when they are in contact with disinfectants leading to theformation of a thin oxidised layer coupled to the cracks initiation of cracks of different lengthsfrom the inner wall surface. An original method is proposed here to characterise the ageingeffect of the pipe mechanical behaviour. Inspired from the ASTM D 2290-04 standard, NolRing tests have been performed under tensile and creep loadings on smooth rings. Aconstitutive equation has been determined from these tests using a finite element (FE)modelling. FE simulations have been performed to study the influence of the thin oxidised PElayer. Precracked specimens with different crack depth ratio have also been modelled. Thecrack depth ratio is an important parameter to quantify pipe ageing

Fracture mechanics of creeping solids applied to pre-cracked NOL ring specimens to predict residual lifetime of high density polyethylene pipes

International audienceHigh Density Polyethylene (HDPE) is widely used for the distribution of drinking water and are exposed to an internal pressure due to water flow. Furthermore, when they are in contact with disinfectants, oxidation of HDPE occurs at the immediate surface of the inner wall. This leads to a decrease in the HDPE molar mass and consequently, to a hardening as well as an embrittlement of the material. The oxidised layer thickness seems to stabilize at 200 μm whatever the initial pipe thickness due to the diffusion of reactive species in the inner wall. Inspections with a scanning electron microscope (SEM) of the inner wall of pipes collected on site, after several years of service, showed a network of cracks. The most noxious (deepest) longitudinal crack propagates under the steady internal pressure until the complete failure of the pipe. The experimental investigations consisted of creep crack growth tests, carried out on an original geometry for this type of test using NOL ring. These specimens were cut from the pipes and an internal longitudinal crack implanted. Creep crack growth tests were performed at various net stresses and at various crack depth ratios. At the end of each test, the time to failure was recorded. Before applying the theory of fracture mechanics of creeping solids, 3D finite element simulations were carried out to assess the suitability of assuming plane strain conditions. To this end, a porous viscoplastic model was implemented into an in-house finite element code. A fracture criterion based on critical porosity allowed for the simulation of creep crack growth. The localization of the maximum damage at mid-thickness and the thickness reduction were well captured. In these conditions, the crack front curvature is located near the surface so that a 2D calculation with plane strain conditions can then be justified to determine the C* load parameter. The residual lifetime of a real pipe containing a longitudinal defect, under in-service loading was estimated by using the correlation between the time to failure and the C*-integral

D 5.5.2. Report on near-market consumer testing of new improved products and substitutes in Africa. Project AFTER “African Food Tradition rEvisited by Research”

In this deliverable, the reengineered products relating to groups 1 to 3 are tested by consumers in Africa in order to test whether the acceptance meets consumer needs. The summaries are by group. These products were widely different and tested in differing cultures and situations. A common feature, however, is that all products are already commonly consumed by the communities and accepted, particularly with respect to the baseline products. Some products were found to be more acceptable (Gowe and Akpan in Benin, Kenkey in Ghana, Kong and Lanhouin in Senegal, Bissap and Baobab in Senegal), some of similar acceptance (Kitoza in Madagascar) and some were less acceptable (Kishk Sa'eedi in Egypt and Jaabi in Cameroon). Ways forward are discussed in all cases. Group 1: The reengineered group 1 products had mixed acceptance to consumers. Ones that were highly accepted were the reengineered Akpan which was highly accepted regardless of age, gender, socio- professional category and possessions (goods) and the majority (84.9%) expressed an interest for purchasing the reengineered Akpan and the reengineered gowe (n=100 consumers) in Benin, which was strongly accepted and more so than the traditional gowe. However, the reengineered Kenkey in Ghana while being comparable acceptance to the traditional white kenkey this would only meet a niche market. However, for the reengineered Kishk Sa'eedi, it was less acceptable and the difference was due to sour taste and spicy flavour. Group 2:The group 2 products had mixed acceptance among consumers. In the case of Kong in and Lanhouin in Senegal, the reengineered products had improved acceptance while for kitoza in Madagascar, there was no improvement in acceptance apart from those in terms of quality and safety. More specifically, Kong made using liquid smoke novel technique (RLK) had by far the highest acceptance and could easily be integrated as part of the Senegalese cuisine. This shows that there is a potential for RLK on the Senegalese market. Two types of reengineered Lanhouin types (Lanhouin dry powder, Lanhouin dry fillet) were greatly acceptable and the powdered form more than the fillet. In the case of Kitoza, consumer acceptance studies showed that there was no significant difference between all samples tested. Group 3: Group 3 reengineered products had mixed acceptance among consumers. Re-engineered bissap (hibiscus drinks) in Senegal were positively appreciated by consumers in Senegal and better accepted than the traditional commercial infusion used as baseline comparison. However, the new drinks were not perceivably different from the baseline drink to consumers concerning both the traditional character and the nutritional and healthy attributes. The reengineered baobab drinks were positively appreciated by consumers in Senegal and significantly better appreciated than the traditional commercial ones earlier tested. Jaabi (Ziziphus mauritiana). The result is the proposition of a reengineered Yaabande presenting fine texture well appreciated by consumers. However, particle size was critical and this needed to be lower than 125μm. Due to this limit, processors have adopted the manual production of flour of particle size 250μm>Ø>125μm, which is less tiresome, though it appears in second rank in the preference of consumers. The detailed methodology for each product is given for Groups I, II and III respectively. Common to all of the methodologies is the Ethical assessment and consent which is listed as follows: Ethical assessment and consent. The studies have been assessed and approved by the University of Greenwich Research Ethics Committee and the Ethics Committee at CIRAD. Consent was sought from sensory panellists and from adult consumers participating in this study. Enumerators informed participants about the study and explained that their participation was entirely voluntary, that they could stop the interview at any point and that the responses would be anonymous

Enabling Technologies of Cyber Crime: Why Lawyers Need to Understand It

This Article discusses the enabling technologies of cyber crime and analyzes their role in the resolution of related legal issues. It demonstrates the translation of traditional legal principles to a novel technological environment in a way that preserves their meaning and policy rationale. It concludes that lawyers who fail to understand the translation will likely pursue a suboptimal litigation strategy, face speculative recovery prospects, and may overlook effective and potentially powerful defenses

Design Considerations of a GPU

With the current era of AI technology, the era of single instruction multiple data has become an increasingly viable solution to accelerate training. The problem is that while software to use GPUs and other hardware accelerators, designing GPUs and ASIC devices has become increasingly more expensive and there aren’t great examples of generic GPUs that anyone can use and modify. In this thesis, there are four design considerations that will be discussed and how they affect the result of a generic GPU. The four considerations that were talked about in the thesis are, word width, arithmetic type, number of stages, and number of memory paths. Throughout, decisions will be made about these design decisions to create an example GPU that will be tested at the end. The set up chosen is to make the GPU an 8-bit word width, integer-based arithmetic computations, single staged pipeline, with 8 memory paths onto and off the chip. The result was a generic GPU that can complete basic calculations

Design Considerations of a GPU

With the current era of AI technology, the era of single instruction multiple data has become an increasingly viable solution to accelerate training. The problem is that while software to use GPUs and other hardware accelerators, designing GPUs and ASIC devices has become increasingly more expensive and there aren’t great examples of generic GPUs that anyone can use and modify. In this thesis, there are four design considerations that will be discussed and how they affect the result of a generic GPU. The four considerations that were talked about in the thesis are, word width, arithmetic type, number of stages, and number of memory paths. Throughout, decisions will be made about these design decisions to create an example GPU that will be tested at the end. The set up chosen is to make the GPU an 8-bit word width, integer-based arithmetic computations, single staged pipeline, with 8 memory paths onto and off the chip. The result was a generic GPU that can complete basic calculations