Network slicing has emerged as a key concept in 5G systems, allowing Mobile Network Operators (MNOs) to build isolated logical networks (slices) on top of shared infrastructure networks managed by ...Infrastructure Providers (InP). Network slicing requires the assignment of infrastructure network resources to virtual network components at slice activation time and the adjustment of resources for slices under operation. Performing these operations just-in-time, on a best-effort basis, comes with no guarantee on the availability of enough infrastructure resources to meet slice requirements. This paper proposes a prioritized admission control mechanism for concurrent slices based on an infrastructure resource reservation approach. The reservation accounts for the dynamic nature of slice requests while being robust to uncertainties in slice resource demands. Adopting the perspective of an InP, reservation schemes are proposed that maximize the number of slices for which infrastructure resources can be granted while minimizing the costs charged to the MNOs. This requires the solution of a max-min optimization problem with a non-linear cost function and non-linear constraints induced by the robustness to uncertainties of demands and the limitation of the impact of reservation on background services. The cost and the constraints are linearized and several reduced-complexity strategies are proposed to solve the slice admission control and resource reservation problem. Simulations show that the proportion of admitted slices of different priority levels can be adjusted by a differentiated selection of the delay between the reception and the processing instants of a slice resource request.
With network slicing in 5G networks, Mobile Network Operators can create various slices for Service Providers (SPs) to accommodate customized services. Usually, the various Service Function Chains ...(SFCs) belonging to a slice are deployed on a best-effort basis. Nothing ensures that the Infrastructure Provider (InP) will be able to allocate enough resources to cope with the increasing demands of some SP. Moreover, in many situations, slices have to be deployed over some geographical area: coverage as well as minimum per-user rate constraints have then to be taken into account. This paper takes the InP perspective and proposes a slice resource provisioning approach to cope with multiple slice demands in terms of computing, storage, coverage, and rate constraints. The resource requirements of the various SFCs within a slice are aggregated within a graph of Slice Resource Demands (SRD). Infrastructure nodes and links have then to be provisioned so as to satisfy all SRDs. This problem leads to a Mixed Integer Linear Programming formulation. A two-step approach is considered, with several variants, depending on whether the constraints of each slice to be provisioned are taken into account sequentially or jointly. Once provisioning has been performed, any slice deployment strategy may be considered on the reduced-size infrastructure graph on which resources have been provisioned. Simulation results demonstrate the effectiveness of the proposed approach compared to a more classical direct slice embedding approach.
Uncertainty-Aware Resource Provisioning for Network Slicing Luu, Quang-Trung; Kerboeuf, Sylvaine; Kieffer, Michel
IEEE eTransactions on network and service management,
2021-March, 2021-3-00, 20210301, 2021-03-01, Letnik:
18, Številka:
1
Journal Article
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Network slicing allows Mobile Network Operators to split the physical infrastructure into isolated virtual networks (slices), managed by Service Providers to accommodate customized services. The ...Service Function Chains (SFCs) belonging to a slice are usually deployed on a best-effort premise: nothing guarantees that network infrastructure resources will be sufficient to support a varying number of users, each with uncertain requirements. Taking the perspective of a network Infrastructure Provider (InP), this article proposes a resource provisioning approach for slices, robust to a partly unknown number of users with random usage of the slice resources. The provisioning scheme aims to maximize the total earnings of the InP, while providing a probabilistic guarantee that the amount of provisioned network resources will meet the slice requirements. Moreover, the proposed provisioning approach is performed so as to limit its impact on low-priority background services, which may co-exist with slices in the infrastructure network. Taking all these constraints into account leads to an integer programming problem with many nonlinear constraints. These constraints are first relaxed to get an integer linear programming formulation of the slice resource provisioning problem. This problem is then solved considering the slice resource provisioning demands jointly. A suboptimal approach is finally proposed where slice resource provisioning demands are considered sequentially. Both solutions are compared to provisioning schemes that do not account for best-effort services sharing the common infrastructure network, as well as uncertainties in the slice resource demands.
Datacenter networks commonly facilitate the transmission of data in distributed computing frameworks through coflows, which are collections of parallel flows associated with a common task. Most of ...the existing research has concentrated on scheduling coflows to minimize the time required for their completion, i.e., to optimize the average dispatch rate of coflows in the network fabric. Nevertheless, modern applications often produce coflows that are specifically intended for online services and mission-crucial computational tasks, necessitating adherence to specific deadlines for their completion. In this paper, we introduce <inline-formula><tex-math notation="LaTeX">\mathtt {WDCoflow}</tex-math> <mml:math><mml:mi mathvariant="monospace">WDCoflow</mml:mi></mml:math><inline-graphic xlink:href="luu-ieq1-3384514.gif"/> </inline-formula>, a new algorithm to maximize the weighted number of coflows that complete before their deadline. By combining a dynamic programming algorithm along with parallel inequalities, our heuristic solution performs at once coflow admission control and coflow prioritization, imposing a <inline-formula><tex-math notation="LaTeX">\sigma</tex-math> <mml:math><mml:mi>σ</mml:mi></mml:math><inline-graphic xlink:href="luu-ieq2-3384514.gif"/> </inline-formula>-order on the set of coflows. With extensive simulation, we demonstrate the effectiveness of our algorithm in improving up to <inline-formula><tex-math notation="LaTeX">3\times</tex-math> <mml:math><mml:mrow><mml:mn>3</mml:mn><mml:mo>×</mml:mo></mml:mrow></mml:math><inline-graphic xlink:href="luu-ieq3-3384514.gif"/> </inline-formula> more coflows that meet their deadline in comparison the best SoA solution, namely <inline-formula><tex-math notation="LaTeX">\mathtt {CS\text{-}MHA}</tex-math> <mml:math><mml:mrow><mml:mi mathvariant="monospace">CS</mml:mi><mml:mtext mathvariant="monospace">-</mml:mtext><mml:mi mathvariant="monospace">MHA</mml:mi></mml:mrow></mml:math><inline-graphic xlink:href="luu-ieq4-3384514.gif"/> </inline-formula>. Furthermore, when weights are used to differentiate coflow classes, <inline-formula><tex-math notation="LaTeX">\mathtt {WDCoflow}</tex-math> <mml:math><mml:mi mathvariant="monospace">WDCoflow</mml:mi></mml:math><inline-graphic xlink:href="luu-ieq5-3384514.gif"/> </inline-formula> is able to improve the admission per class up to <inline-formula><tex-math notation="LaTeX">4\times</tex-math> <mml:math><mml:mrow><mml:mn>4</mml:mn><mml:mo>×</mml:mo></mml:mrow></mml:math><inline-graphic xlink:href="luu-ieq6-3384514.gif"/> </inline-formula>, while increasing the average weighted coflow admission rate.
With network slicing, Mobile Network Operators can accommodate on a common network infrastructure various customized services from Service Providers (SPs). Usually, the Service Function Chains ...belonging to a slice are deployed on a best-effort basis. Nothing ensures that enough infrastructure resources can be allocated to satisfy the demands of SPs. This paper introduces a radio resources provisioning approach to satisfy the demands of slices with radio coverage constraints. By provisioning, we ensure that enough resources are reserved for further SFC deployment. Numerical results show the effectiveness of the proposed provisioning framework for a slice deployment on a mobile network infrastructure satisfying a minimum data rate for users in the geographical areas where services have to be made available.
With the advent of big data applications, coflow scheduling has become a cornerstone for the engineering of traffic in datacenters. Minimizing the average weighted Coflow Completion Times (CCT) is a ...crucial step to minimize the execution time of jobs running in distributed computing frameworks. In this paper, we present a new σ-order coflow scheduling solution, ONE-PARIS, an online semi-clairvoyant and semi-distributed implementation suitable to minimize the weighted CCT in production environments. We achieves this through ONE-PARIS scheduler for ordering coflows and a decentralized resource allocation mechanism, called Sync-Rate, enabling to respect the order of priority of coflows provided by ONE-PARIS and ensuring efficient synchronization between flows of the same coflow in order to free up bandwidth for low-priority flows. Extensive simulations on both synthetic and real traffics show that our proposed coflow scheduler outperforms other state-of-art schemes.
In field survey,
Pteris vittata
and
Pityrogramma calomelanos
were only found in arsenic (As) contaminated areas with soil pH 7.2–8.8 and 2.3–4.2, respectively. In the first pot experiment, two fern ...species were grown on the soil amended with 300 mg kg
−1
As at soil pH of 5.1, 7.2 and 9.
P. calomelanos
survived all pH treatments, and had the highest frond As concentration and soil As removal efficiency at soil pH 5.1. All
P. vittata
plants were dead at soil pH 5.1.
P. vittata
had higher frond As concentration, biomass and the amount of As removed from the soil than those of
P. calomelanos
at soil pH of 7.2 and 9. In the second pot experiment,
P. vittata
was demonstrated to have greater life time, biomass, As tolerance and accumulation than those of
P. calomelanos
as planted on alkaline soil (pH 7.8) spiked with various concentrations of As.
Illicit drug use is a serious issue in Vietnam, but information about their prevalence is scarce, mainly based on seizure data. Wastewater-based epidemiology (WBE) is an alternative tool for ...obtaining such information, especially when stigma related to drug use can hinder survey approaches. The study aimed to apply WBE to assess the prevalence of use of a range of illicit drugs in an urban population of Vietnam. A total of 184 wastewater samples were collected at two different sites along a sewage canal, receiving sewage from over 400,000 people in Hanoi, Vietnam, in three different periods between 2018 and 2020. Illicit drugs and their metabolites were measured by direct injection using liquid chromatography-tandem mass spectrometry. The results were back-estimated, normalised to per capita daily consumption for assessement of consumption patterns and trends. Most drugs were detected in all the samples except cocaine, benzoylecgonine, amphetamine indicating a low prevalence of cocaine and amphetamine use. The estimated consumption level of methamphetamine was varied from 119.5 to 553.5 mg/d/1000 pp. The market of illicit drugs in Vietnam has changed from opiates to amphetamine-type simulants, and methamphetamine has replaced heroin as the No.1 drug, its use can be as much as 3 times more than heroin use. Moreover, we observed the considerable and potentially increasing level of ketamine consumption in Hanoi. No statistical difference was found in daily consumption per capita among days of the week for any drugs, both legal (codeine, methadone) and illegal (methamphetamine, MDMA, ketamine and heroin), suggesting the drugs were consumed mainly by regular users. This study provides important information related the illicit drug consumption in Vietnam, which will help to formulate appropriate drug control policies in this country.
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•Methamphetamine, heroin, ketamine, and MDMA were the dominant illicit drugs in Hanoi•Methamphetamine replaced heroin as the No. 1 illicit drug, with level of use almost 3 times higher.•Ketamine showed increasing level of consumption over time.•No difference in the level of consumption among days of the week for all drugs.
Developing biostimulants from salt-tolerant plant growth-promoting (PGP) bacteria is an emerging strategy for sustainable agriculture in the context of increasing soil salinization. This study aimed ...to isolate endophytic bacteria (EB) capable of promoting rice seed germination and seedling growth at different NaCl concentrations. Nine salt-tolerant EB strains were isolated and two, ST.6 and ST.8, with the rice seed promoting effect 99.3 and 99.7 %, respectively, were selected and identified as Pantoea dispersa and Burkholderia cenocepacia, respectively. ST.6 showed a higher value of the activity of phosphatase (617 mg P ml-1), production of indole-3-acetic acid (19.7 µg IAA ml-1), the activity of 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase (13.5 µmol mg−1 protein h−1), and production of siderophore (76.3 %). Especially, rice seedlings inoculated with strain ST.6 showed a significant improvement in root length (58.95 %), shoot length (16.6 %), dry biomass (7.0 %), the content of chlorophyll (46.2 and 57.1 % for chlorophyll a and b, respectively), carotenoids (22.2%), and proline (19.0 %). A decrease in antioxidant enzyme activities was also observed in the rice seedlings inoculated with either ST.6 or ST.8 strain under salt stress. Furthermore, the salt stress condition enhanced the colonization of roots by both studied endophytic bacteria. More experiments should be done to develop endophytic bacteria ST.6 and ST.8 as efficient bio-inoculants.
In soil, a large amount of supplemented phosphorus (P) are immediately transferred into insoluble forms and only 0.1 % of them is available for plant uptake. Therefore, exploring naturally occurring ...phosphate-solubilizing microorganisms is an essential activity to exploit them in reducing mineral phosphorus added to agricultural soils. In this study, we screened and isolated 7 bacteria that solubilized phosphate at different phosphate solubilization indexes, ranging from 4.2 to 226.1. Of them, the most efficient isolate is PSB31, which solubilized tri calcium phosphate (Ca3(PO4)2 at a rate of 962 mg l-1 and molecularly identified as Bacillus sp. (in: Bacteria) strain IMAU61039. This bacterial strain generated the low supernatant pH and the phosphatase, which are involved in the phosphorus solubilization mechanism. Furthermore, greenhouse experiments showed that tomato seedlings grown in PSB31-inoculated soil contained higher P amount and had much higher biomass than those plants grown in soil without PSB31 addition. These results suggest that the PSB31 strain has potential use as a biofertilizer.
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