Migration energy aware reconfigurations of virtual network function instances in NFV architectures

Network function virtualization (NFV) is a new network architecture framework that implements network functions in software running on a pool of shared commodity servers. NFV can provide the infrastructure flexibility and agility needed to successfully compete in today's evolving communications landscape. Any service is represented by a service function chain (SFC) that is a set of VNFs to be executed according to a given order. The running of VNFs needs the instantiation of VNF instances (VNFIs) that are software modules executed on virtual machines. This paper deals with the migration problem of the VNFIs needed in the low traffic periods to turn OFF servers and consequently to save energy consumption. Though the consolidation allows for energy saving, it has also negative effects as the quality of service degradation or the energy consumption needed for moving the memories associated to the VNFI to be migrated. We focus on cold migration in which virtual machines are redundant and suspended before performing migration. We propose a migration policy that determines when and where to migrate VNFI in response to changes to SFC request intensity. The objective is to minimize the total energy consumption given by the sum of the consolidation and migration energies. We formulate the energy aware VNFI migration problem and after proving that it is NP-hard, we propose a heuristic based on the Viterbi algorithm able to determine the migration policy with low computational complexity. The results obtained by the proposed heuristic show how the introduced policy allows for a reduction of the migration energy and consequently lower total energy consumption with respect to the traditional policies. The energy saving can be on the order of 40% with respect to a policy in which migration is not performed

The effect of nano-silica on the performance of Portland cement mortar

Nanotechnology has nowadays a pronounced impact on several areas of science and industry. Among several advantages, nanomaterials have been reported to introduce improvements in terms of system reliability, extend functionality beyond traditional applications and decrease energy consumption in structures. Nanomaterials can enable better utilization of natural resources and reaching required materials properties with minimal usage. Nano-cement and nano-silica are among the recently used materials in this regard. The objective of this study is to explore the effect of incorporating nano-silica to cement mortar on enhancing mechanical properties and durability. Three types of nano silica with three nominal particle sizes have been used with two percentages (4% and 8% per weight of cement) and a w/c of 0.4. Testing program included compressive strength, tensile strength, rapid chloride permeability, microstructure analysis, chemical durability and the effect of mixing techniques on strength. The results were compared against both ordinary Portland cement mortar a well as conjugate mortar with 8% of cement silica fume. Results reveal adding nano-silica to cement mortar enhances its physical and mechanical properties such as compressive strength, tensile strength, permeability and chemical durability. The SEM pictures demonstrate that nano-silica contributes to enhancement of mortar through yielding denser, more compact and uniform mixtures. It was also found that nano-silica is superior to silica fume in enhancing the properties of cement mortar although a generalization at that stage needs further examination. The findings of this study should be validated by wider studies and testing scheme. It is recommended that codes of practice should be introduced for testing construction materials with nano-particles

The Level of Acceptance of Preservice Teachers at Kuwait University for Infographics Applications in Light of the Information and Communication Technology Acceptance Model “ICTAM”

This study aimed to determine the level of acceptance of infographics apps among preservice teachers at Kuwait University and examine the effect of several independent variables on the level of acceptance. It used exploratory quasi- experimental descriptive analysis based primarily on a quantitative approach and specifically adopted the information and communication technology acceptance model (ICTAM). A stratified sample of 162 preservice female teachers from the College of Education at Kuwait University participated in this study. The participants were introduced to and trained on various infographics apps. At the end of the semester, an anonymous questionnaire was administered through an online survey tool, and the preservice teachers were asked to voluntarily participate and complete the questionnaire. A set of descriptive statistics (i.e., frequencies, percentages, means, and standard deviations) and inferential comparisons tests (i.e., independent-samples t-tests, one-way analyses of variance “ANOVAs”, Dunnett’s C multiple comparisons tests, and Scheffe’s multiple comparisons tests) were employed to analyze the data. The findings revealed that the level of acceptance among preservice teachers regarding the use of infographics apps was “high” (M = 3.85, SD = 0.67). Although the results uncovered a few significant differences with regard to some independent variables (i.e., year of study, ICT daily usage, and GPA), the level of overall acceptance of the infographics apps was very high

Effect of clindamycin vaginal pessary before cesarean section on postpartum infectious morbidity

Background: Post-cesarean section (CS) infections, namely, endometritis, fever and wound infection are considered a major health problem which necessitates effective interventions. Antibiotic prophylaxis before CS cannot completely eliminate the risk of postpartum infections. Preoperative antiseptic vaginal cleansing is one of the commonest methodsto reduce infectious morbidities after CS. Aim of the work: The aim of this work is to evaluate the effect of prophylactic administration of clindamycin vaginal suppository before elective CS on postpartum infectious morbidity. Methods: 196 patients were included in this intervention. They were divided equally into two groups (each 98 patients); intervention group (which received clindamycin 100 mg vaginal suppository at bedtime for 3 nights before CS) and control group (which received nothing). Both groups were followed till the end of puerperium for the development of postpartum infections namely, endometritis, fever, and wound infection. Results: There was statistically significant decrease in the frequency of endometritis, fever, and wound infection in the intervention group when compared to control group. Also, there was highly statistically significant decrease in the frequency of overall post-CS infectious morbidity in the intervention group when compared to control group. There was statistically significant difference between both groups as regard white blood cells count and C-reactive protein level 24 hours after cesarean section. Conclusion: Prophylactic administration of clindamycin vaginal suppository before elective CS reduces the risk of postpartum infections namely endometritis, fever, wound infection and overall post-CS infectious morbidity. Preoperative clindamycin vaginal suppository could be  protective against post-CS infectious morbidities

An effective technique for increasing capacity and improving bandwidth in 5G narrow-band internet of things

In recent years, the wireless spectrum has become increasingly scarce as demand for wireless services has grown, requiring imaginative approaches to increase capacity within a limited spectral resource. This article proposes a new method that combines modified symbol time compression with orthogonal frequency division multiplexing (MSTC-OFDM), to enhance capacity for the narrow-band internet of things (NB-IoT) system. The suggested method, MSTC-OFDM, is based on the modified symbol time compression (MSTC) technique. The MSTC is a compressed waveform technique that increases capacity by compressing the occupied symbol time without losing bit error rate (BER) performance or data throughput. A comparative analysis is provided between the traditional orthogonal frequency division multiplexing (OFDM) system and the MSTC-OFDM method. The simulation results show that the MSTC-OFDM scheme drastically decreases the symbol time (ST) by 75% compared to a standard OFDM system. As a result, the MSTC-OFDM system offers four times the bit rate of a typical OFDM system using the same bandwidth and modulation but with a little increase in complexity. Moreover, compared to an OFDM system with 16 quadrature amplitude modulation (16QAM-OFDM), the MSTC-OFDM system reduces the signal-to-noise ratio (SNR) by 3.9 dB to transmit the same amount of data

Overlay Network Assignment in PlanetLab With NetFinder

PlanetLab has been widely used in the networking community to test and deploy user-defined overlays. Serving as a meta testbed to support multiple overlay networks, PlanetLab has significantly lowered the barriers to build new overlays. However, PlanetLab users always face the problem of selecting a set of nodes and interconnecting them to form the desired overlay network. Unfortunately, such a task is usually carried out manually by individual users and sometimes in an ad-hoc manner. In this paper, we develop NetFinder, an automatic overlay network configuration tool to efficiently allocate PlanetLab resources to individual overlays. NetFinder continuously monitors the resource utilization of PlanetLab and accepts a user-defined overlay topology as input and selects the set of PlanetLab nodes and their interconnection for the user overlay. Experimental results indicate that overlay networks constructed by NetFinder have more stable and significantly higher bandwidth than alternative schemes and near optimal available CPU