Minimum-Cost Virtual Network Function Resilience

International audienceIn the future 5G networks, a wide range of new services with strong requirements will be delivered in the form of chains of service functions on independent virtual networks. These virtual networks will be deployed on demand, each one adapted to the specific service requirements. For infrastructure providers a real challenge consists in providing and setting up the required virtual networks (network slices) while guaranteeing strict Service Level Agreements. One of the major stakes is to be able to provide failure protection for the service function chains at minimal cost. In this work, we consider a set of deployed service chains, and we study the best strategy to protect them at minimal cost. We propose mathematical formulations that provide optimal backup functions placement over a network, and the associated backup paths for each VNF of all the chains. We develop an efficient ILP-based heuristic relying on a separation of the problem into smaller ones to solve large scale instances. We show that our heuristic is competitive, both regarding the solution quality and the solving time

Squeezing Flow of Suspensions: Flow Regime Evaluation from Energy Approach

International audienceThe squeezing flow geometry is here used to investigate the properties of concentrated suspensions. The suspensions consist in idealized system of smooth hard spheres dispersed in a yield stress colloidal gel. During the squeezing action, the material structure evolves with energy variation due to particle displacement and interaction. The goal of our study is to evaluate the energy evolution from a Fourier analysis as a function of solid volume fraction and compression velocity

The Back Extrusion Test as a Technique for Determining the Rheological and Tribological Behaviour of Yield Stress Fluids at Low Shear Rates

The original contribution is available at http://www.ar.ethz.ch/International audienceA new method is developed to determine the rheological and tribological behaviour of viscoplastic fluids using a back extrusion test. In back extrusion geometry, the material is forced to flow in the gap between the inner and the outer cylinder. Such a flow is modelled by a Bingham constitutive law under different wall boundary conditions (stick, slip with friction and perfect slip). When steady-state flow is reached, an apparent shear rate is computed. The analysis of the inner cylinder penetration force versus the penetration depth helps us to develop a method to identify the fluid rheological and tribological properties. This method is based on an inverse analysis to identify the fluid behaviour parameters from experiments performed at different ram velocities and with different apparatus geometries. In order to study more complex fluids (Herschell-bulkley rheological behaviour, for example), an equivalent flow curve is plotted from tests characterized by different average shear rates. The tribological behaviour is identified using different wall boundary conditions, varying the surface roughness of the cylinders. The method is applied to oil/sugar suspension and plasticine. Rheological and tribological behaviours are identified and results are compared with those obtained under steady state shear flow. The obtained rheological parameters are close to those provided by the common rheological methods (difference lower than 15 %)

Efficient multibeam sonar calibration and performance evaluation

Quantitative applications of mobile multibeam sonar in aquatic ecology and fisheries require accurate and efficient in-tank calibration methodologies. Calibration factors for a Simrad SM20 multibeam sonar are experimentally extracted thereby enabling sonar estimation of target strength and volume backscattering strength. Measured and modeled sonar characteristics are systematically compared and show good overall correlation. Due to the limited angular span of the sonar head array, well quantified sonar operation is restricted to an equatorial angular sector of only 80° (vs. rated 120°) in 'imaging' mode. In 'echo-sounder' mode, the 'high' power transmit setting appears to introduce artifacts. A routine in-tank measurement procedure is described which for given multibeam sonar minimizes the time required for quality multibeam calibration

Etude du comportement visqueux-visco-plastique de suspensions sédimentaires multi-échelle

International audienc

Use of ram extruder as a combined rheo-tribometer to study the behaviour of high yield stress fluids at low strain rate

International audienceWe propose in this work to provide an efficient and simple extruder device able to evaluate the rheological and tribological behaviour of high yield stress fluids, such as extrudible materials. An extruder able to measure simultaneously both the friction force acting on the extruder wall and the total extrusion force is developed. Based on previous studies, an efficient and accurate method of data analysis is then proposed and applied in order to obtain both a flow curve and a tribological law. Experimental tests are performed on soft modelling clay, kaolin paste and cement-based materials. Results are compared to conventional rheometry measurements. This comparison helps to evaluate the accuracy of the proposed experimental device and procedure

Fine-scale vertical structure of sound-scattering layers over an east border upwelling system and its relationship to pelagic habitat characteristics

Understanding the relationship between sound-scattering layers (SSLs) and pelagic habitat characteristics is a substantial step to apprehend ecosystem dynamics. SSLs are detected on echo sounders representing aggregated marine pelagic organisms. In this study, SSL characteristics of zooplankton and micronekton were identified during an upwelling event in two contrasting areas of the Senegalese continental shelf. Here a cold upwelling-influenced inshore area was sharply separated by a strong thermal boundary from a deeper, warmer, stratified offshore area. Mean SSL thickness and SSL vertical depth increased with the shelf depth. The thickest and deepest SSLs were observed in the offshore part of the shelf. Hence, zooplankton and micronekton seem to occur more frequently in stratified water conditions rather than in fresh upwelled water. Diel vertical and horizontal migrations of SSLs were observed in the study area. Diel period and physicochemical water characteristics influenced SSL depth and SSL thickness. Although chlorophyll-a concentration insignificantly affected SSL characteristics, the peak of chlorophyll a was always located above or in the middle of the SSLs, regularly matching with the peak of SSL biomass. Such observations indicate trophic relationships, suggesting SSLs to be mainly composed of phytoplanktivorous zooplankton and micronekton. Despite local hypoxia, below 30 m depth, distribution patterns of SSLs indicate no vertical migration boundary. The results increase the understanding of the spatial organization of mid-trophic species and migration patterns of zooplankton and micronekton, and they will also improve dispersal models for organisms in upwelling regions.publishedVersio

Association of Long-term Exposure to Elevated Lipoprotein(a) Levels With Parental Life Span, Chronic Disease-Free Survival, and Mortality Risk: A Mendelian Randomization Analysis.

IMPORTANCE: Elevated lipoprotein(a) (Lp[a]) levels are associated with atherosclerotic cardiovascular diseases. The association between high Lp(a) levels and human longevity phenotypes is, however, controversial. OBJECTIVE: To examine whether genetically determined Lp(a) levels are associated with parental life span and chronic disease-free survival (health span) and the association between Lp(a) levels and long-term, all-cause mortality risk. DESIGN, SETTING, AND PARTICIPANTS: In this genetic association study, cross-sectional mendelian randomization (UK Biobank [2006-2010] and LifeGen Consortium) and prospective analyses (European Prospective Investigation Into Cancer and Nutrition (EPIC)-Norfolk [1993-1997, with patients followed up to 2016]) were conducted using individual-level data on 139 362 participants. The association between a weighted genetic risk score of 26 independent single-nucleotide polymorphisms at the LPA locus on parental life span using individual participant data from the UK Biobank, as well as with summary statistics of a genome-wide association study of more than 1 million life spans (UK Biobank and LifeGen), were examined. The association between these single-nucleotide polymorphisms and the age at the end of the health span was tested using summary statistics of a previous genome-wide association study in the UK Biobank. The association between Lp(a) levels and all-cause mortality in the EPIC-Norfolk study was also investigated. Data were analyzed from December 2018 to December 2019. EXPOSURES: Genetically determined and measured Lp(a) levels. MAIN OUTCOMES AND MEASURES: Parental life span, health span, and all-cause mortality. RESULTS: In 139 362 white British participants (mean [SD] age, 62.8 [3.9] years; 52% women) from the UK Biobank, increases in the genetic risk score (weighted for a 50-mg/dL increase in Lp[a] levels) were inversely associated with a high parental life span (odds ratio, 0.92; 95% CI, 0.89-0.94; P = 2.7 × 10-8). Using the Egger-mendelian randomization method, a negative association between LPA single-nucleotide polymorphisms and parental life span (mean [SD] Egger-mendelian randomization slope, -0.0019 [0.0002]; P = 2.22 × 10-18) and health span (-0.0019 [0.0003]; P = 3.00 × 10-13) was noted. In 18 720 participants from EPIC-Norfolk (5686 cases), the mortality risk for those with Lp(a) levels equal to or above the 95th percentile was equivalent to being 1.5 years older in chronologic age (β coefficient [SE], 0.194 [0.064]). CONCLUSIONS AND RELEVANCE: The results of this study suggest a potential causal effect of absolute Lp(a) levels on human longevity as defined by parental life span, health span, and all-cause mortality. The results also provide a rationale for trials of Lp(a)-lowering therapy in individuals with high Lp(a) levels

Sex-Specific Associations of Genetically Predicted Circulating Lp(a) (Lipoprotein(a)) and Hepatic LPA Gene Expression Levels With Cardiovascular Outcomes: Mendelian Randomization and Observational Analyses.

BACKGROUND: Elevated Lp(a) (Lipoprotein(a)) levels are associated with coronary artery disease (CAD), ischemic stroke (IS), and calcific aortic valve stenosis (CAVS). Studies investigating the association between Lp(a) levels and these diseases in women have yielded inconsistent results. METHODS: To investigate the association of Lp(a) with sex-specific cardiovascular outcomes, we determined the association between genetically predicted Lp(a) levels (using 27 single nucleotide polymorphisms at the LPA locus) and hepatic LPA expression (using 80 single nucleotide polymorphisms at the LPA locus associated with LPA mRNA expression in liver samples from the Genotype-Tissue Expression dataset) on CAD, IS, and CAVS using individual participant data from the UK Biobank: 408 403 participants of European ancestry (37 102, 4283, and 2574 with prevalent CAD, IS, and CAVS, respectively). The long-term association between Lp(a) levels and incident CAD, IS, and CAVS was also investigated in European Prospective Investigation into Cancer and Nutrition-Norfolk: 18 721 participants (3964, 846, and 424 with incident CAD, IS, and CAVS, respectively). RESULTS: Genetically predicted plasma Lp(a) levels were positively and similarly associated with prevalent and incident CAD and CAVS in men and women. Genetically predicted plasma Lp(a) levels were associated with prevalent and incident IS when we studied men and women pooled together, and in men only. Genetically predicted LPA expression levels were associated with prevalent CAD and CAVS in men and women but not with IS. CONCLUSIONS: Genetically predicted blood Lp(a) and hepatic LPA gene expression as well as serum Lp(a) levels predict the risk of CAD and CAVS in men and in women. Whether RNA interference therapies aiming at lowering Lp(a) levels could be useful in reducing cardiovascular disease risk in both men and women with high Lp(a) levels needs to be determined in large-scale cardiovascular outcomes trials

The owner, the provider and the subcontractors : how to handle accountability and liability management for 5G end to end service

The adoption of 5G services depends on the capacity to provide high-value services. In addition to enhanced performance, the capacity to deliver Security Service Level Agreements (SSLAs) and demonstrate their fulfillment would be a great incentive for the adoption of 5G services for critical 5G Verticals (e.g., service suppliers like Energy or Intelligent Transportation Systems) subject to specific industrial safety, security or service level rules and regulations (e.g., NIS or SEVESO Directives). Yet, responsibilities may be difficult to track and demonstrate because 5G infrastructures are interconnected and complex, which is a challenge anticipated to be exacerbated in future 6G networks. This paper describes a demonstrator and a use case that shows how 5G Service Providers can deliver SSLAs to their customers (Service Owners) by leveraging a set of network enablers developed in the INSPIRE-5Gplus project to manage their accountability, liability and trust placed in subcomponents of a service (subcontractors). The elaborated enablers are in particular a novel sTakeholder Responsibility, AccountabIity and Liability deScriptor (TRAILS), a Liability-Aware Service Management Referencing Service (LASM-RS), an anomaly detection tool (IoT-MMT), a Root Cause Analysis tool (IoT-RCA), two Remote Attestation mechanisms (Systemic and Deep Attestation), and two Security-by-Orchestration enablers (one for the 5G Core and one for the MEC)