Cost Minimization of Virtual Machine Allocation in Public Clouds Considering Multiple Applications

International Conference, GECON 2017 (14. 2017. Biarritz)This paper presents a virtual machine (VM) allocation strategy to optimize the cost of VM deployments in public clouds. It can simultaneously deal with multiple applications and it is formulated as an optimization problem that takes the level of performance to be reached by a set of applications as inputs. It considers real characteristics of infrastructure providers such as VM types, limits on the number VMs that can be deployed, and pricing schemes. As output, it generates a VM allocation to support the performance requirements of all the applications. The strategy combines short-term and long-term allocation phases in order to take advantage of VMs belonging to two different pricing categories: on-demand and reserved. A quantization technique is introduced to reduce the size of the allocation problem and, thus, significantly decrease the computational complexity. The experiments show that the strategy can optimize costs for problems that could not be solved with previous approache

Využití NFV v cloud datovém centru

Problematics of reliable and secure set up of virtual network service for orchestrators in cloud environment is a part with high degree of risk within its implementation from the functionality and security point of view. This degree of risk is greatly influenced by the implementer who can make, intentionally or unintentionally, a number of mistakes that may have both security and economic implications. The aim of this article is to introduce the SaltStack orchestration procedure by which the virtual network service can be deployed automatically. The introduced procedure that allows to install cluster of the Avivantage software load-balancer controller is automated. Procedure also includes all necessary dependencies in a specific OpenStack environment by calling a single command. The created procedure shows the general procedures for creating a VNF rule for orchestrators. The introduced rule has been successfully tested on a real-world environment running on the OpenStack cloud platform with OpenContrail's network solution.Problematika spolehlivého a bezpečného nastavení virtuální síťové služby v cloud prostředí pro orchestrátory patří v rámci jejich iplementace k části s vysokou mírou rizika jak z pohledu funkčnosti a bezoečnosti. Tato míra rizika je výrazně ovlivněna samotným iplementátorem, který úmyslně i neúmyslně může do iplementace zanést řadu chyb, které mohou mít jak bezpečnostní tak ekonomický dopad. Cílem předloženého článku je tedy představit postup tvorby předpisu orchestrátor Salt, pomocí kterého je možné automatizovaně nasadit virtuální sít’ovou službu. Je tak zautomatizován proces, který umožňuje nainstalovat softwarový load-balanceru AviVantage . Vytvořený předpis také ukazuje obecné postupy pro vytváření předpisu VNF pro orchestrátory. Navržený předpis byl úspěšně otestován v reálném prostředí využívající platformu OpenStack a OpenContrail

Vertex-Fused Metallaborane Clusters: Synthesis, Characterization and Electronic Structure of [(eta(5)-C(5)Me(5)Mo)(3)MoB(9)H(18)]

The reaction of the [(eta(5)-C(5)Me(5))MoCl(4)] complex with [LiBH4 - TH F] in toluene at - 70 degrees C, followed by pyrolysis at 110 degrees C, afforded dark brown [(eta(5)-C(5)Me(5)Mo)(3)MoB(9)H(18)], 2, in parallel with the known [(eta(5)-C(5)Me(5)Mo)(2)B(5)H(9)], 1. Compound 2 has been characterized in solution by (1)H, (11)B, and (13)C NMR spectroscopy and elemental analysis, and the structural types were unequivocally established by crystallographic studies. The title compound represents a novel class of vertex-fused clusters in which a Mo atom has been fused in a perpendicular fashion between two molybdaborane clusters. Electronic structure calculations employing density functional theory yield geometries in agreement with the structure determinations, and on grounds of density functional theory calculations, we have analyzed the bonding patterns in the structure

Maternal hypertension increases risk of pre-eclampsia and low fetal birthweight: genetic evidence from a Mendelian randomization study

Background: Maternal cardiovascular risk factors have been associated with adverse maternal and fetal outcomes. Given the difficulty in establishing causal relationships using epidemiological data, we applied Mendelian randomization to explore the role of cardiovascular risk factors on risk of developing pre-eclampsia or eclampsia, and low fetal birthweight. Methods: Uncorrelated single nucleotide polymorphisms associated systolic blood pressure, body mass index, type 2 diabetes mellitus, low-density lipoprotein with cholesterol, smoking, urinary albumin-to-creatinine ratio and estimated glomerular filtration rate at genome-wide significance in studies of 298,957 to 1,201,909 European ancestry participants were selected as instrumental variables. A two-sample Mendelian randomization study was performed with primary outcome of pre-eclampsia or eclampsia (PET). Risk factors associated with PET were further investigated for their association with low birthweight. Results: Higher genetically-predicted systolic blood pressure was associated increased risk of PET [odds ratio (OR) per 1-SD systolic blood pressure increase 1.90 (95% confidence interval (CI)1.45-2.49;p=3.23x10-6 and reduced birthweight (OR=0.83; 95%CI=0.79-0.86;p=3.96x10-18), and this was not mediated by PET. Body mass index and type 2 diabetes were also associated with PET (respectively, OR per 1-SD body mass index increase=1.67 95%CI=1.44-1.94,;p=7.45x10-12; and OR per logOR increase type 2 diabetes=1.11 95%CI=1.04-1.19p;=1.19x10-3), but not with reduced birthweight. Conclusions: Our results provide evidence for causal effects of systolic blood pressure, body mass index and type 2 diabetes on PET, and identify that systolic blood pressure is associated with reduced birthweight independently of PET. The results provide insight into the pathophysiological basis of PET and identify hypertension as a potentially modifiable risk factor amenable to therapeutic intervention

SixC1 12xO2 alloys: A possible route to stabilize carbon-based silica-like solids?

Novel extended tetrahedral forms Of CO2 have been synthesized recently under high-pressure conditions. We perform ab initio density functional theory calculations to investigate whether doping with Si can extend the stability range of such tetrahedral forms Of CO2 to ambient pressure. Calculations are performed with a simple cubic cell containing eight formula units in alpha-cristobalite-like structure. Though we find that all the SiC1-xO2 structures considered by us are thermodynamically unstable with respect to decomposition into the end members at ambient pressures, the energy differences are small, suggesting that it might be possible for such phases to exist in metastable forms. At higher pressures, the heat of formation is found to be negative. The bonding between C and O atoms is more covalent than that between Si and 0 atoms. We also find indications that some C atoms may prefer three-fold coordination at low pressur