Spatial-temporal video quality metric based on an estimation of QoE

International audienceIn this work a new Reduced Reference (RR) Video Quality Metric (VQM) is proposed. The method takes advantage of the Human Visual System (HVS) sensitivity to sharp changes in the video. In the first step, the matching regions are calculated using a temporal approach. The quality of these regions are then evaluated using a spatial approach in the last step the quality of the video is calculated based on the parameters gathered in the spatial and temporal domain. An important improvement lies in taking into account the Quality of Experience (QoE) represented as the motion activity density of the reference video. Due to the spatial-temporal approach taken, the metric is named STAQ (Spatial-Temporal Assessment of Quality). The results show a great improvement in the case of H.264 and MPEG-2 compressed and IP distorted videos even when compared to state of the art Full Reference (FR) metrics

A new congestion control algorithm for active networks

This paper discusses and analyses different congestion control schemes for active networks and proposes a new one. The proposed scheme strikes a balance between the number of errors considered and the waiting time before taking action. The scheme implemented works on "Choke packet" concept, where the source is instructed to reduce the transmission rate. Reasonable reduction of transmission rate is maintained at the source as the intermediate nodes in active networks platform take actions instead of the usually acting destination nodes. The proposed scheme was simulated using OPNET and simulation results are reported. Results indicate that the source-quenching technique implemented in the intermediate nodes of the active network reduces congestion drastically and improves overall network performance

Mobility Prediction for Handover Management in Cellular Networks with Control/Data Separation

In research community, a new radio access network architecture with a logical separation between control plane (CP) and data plane (DP) has been proposed for future cellular systems. It aims to overcome limitations of the conventional architecture by providing high data rate services under the umbrella of a coverage layer in a dual connection mode. This configuration could provide significant savings in signalling overhead. In particular, mobility robustness with minimal handover (HO) signalling is considered as one of the most promising benefits of this architecture. However, the DP mobility remains an issue that needs to be investigated. We consider predictive DP HO management as a solution that could minimise the out-of-band signalling related to the HO procedure. Thus we propose a mobility prediction scheme based on Markov Chains. The developed model predicts the user's trajectory in terms of a HO sequence in order to minimise the interruption time and the associated signalling when the HO is triggered. Depending on the prediction accuracy, numerical results show that the predictive HO management strategy could significantly reduce the signalling cost as compared with the conventional non-predictive mechanism

Evaluation of an Improved Chitosan Scaffold Cross-Linked With Polyvinyl Alcohol and Amine Coupling Through 1-Ethyl-3-(3-Dimethyl Aminopropyl)-Carbodiimide (EDC) and 2 N-Hydroxysuccinimide (NHS) for Corneal Applications

BACKGROUND: Corneal blindness resulting from various medical conditions affects millions worldwide. The rapid developing tissue engineering field offers design of a scaffold with mechanical properties and transparency similar to that of the natural cornea. AIM: The present study aimed at to prepare and investigate the properties of PVA/chitosan blended scaffold by further cross-linking with 1-Ethyl-3-(3-dimethyl aminopropyl)-carbodiimide (EDC) and 2 N-Hydroxysuccinimide (NHS) as potential in vitro carrier for human limbal stem cells delivery. MATERIAL AND METHODS: Acetic acid dissolved chitosan was added to PVA solution, uniformly mixed with a homogenizer until the mixture was in a colloidal state, followed by H2SO4 and formaldehyde added and the sample was allowed to cool, subsequently it was poured into a tube and heated in an oven at 60°C for 50 minutes. Finally, samples were soaked in a cross-linking bath with EDC, NHS and NaOH in H2O/EtOH for 24 h consecutively stirred to cross-link the polymeric chains, reduce degradation. After soaking in the bath, the samples were carefully washed with 2% glycine aqueous solution several times to remove the remaining amount of cross-linkers, followed by washed with water to remove residual agents. Later the cross-linked scaffold subjected for various characterization and biological experiments. RESULTS: After viscosity measurement, the scaffold was observed by Fourier transform infrared (FT-IR). The water absorbency of PVA/Chitosan was increased 361% by swelling. Compression testing demonstrated that by increasing the amount of chitosan, the strength of the scaffold could be increased to 16×10−1 MPa. Our degradation results revealed by mass loss using equation shows that scaffold degraded gradually imply slow degradation. In vitro tests showed good cell proliferation and growth in the scaffold. Our assay results confirmed that the membrane could increase the cells adhesion and growth on the substrate. CONCLUSION: Hence, we strongly believe the use of this improved PVA/chitosan scaffold has potential to cut down the disadvantages of the human amniotic membrane (HAM) for corneal epithelium in ocular surface surgery and greater mechanical strength in future after successful experimentation with clinical trials

Impact of distributed generation on protection and voltage regulation of distribution systems : a review

During recent decades with the power system restructuring process, centralized energy sources are being replaced with decentralized ones. This phenomenon has resulted in a novel concept in electric power systems, particularly in distribution systems, known as Distributed Generation (DG). On one hand, utilizing DG is important for secure power generation and reducing power losses. On the other hand, widespread use of such technologies introduces new challenges to power systems such as their optimal location, protection devices' settings, voltage regulation, and Power Quality (PQ) issues. Another key point which needs to be considered relates to specific DG technologies based on Renewable Energy Sources (RESs), such as wind and solar, due to their uncertain power generation. In this regard, this paper provides a comprehensive review of different types of DG and investigates the newly emerging challenges arising in the presence of DG in electrical grids.fi=vertaisarvioitu|en=peerReviewed

Co-application of ACC deaminase-producing rhizobial bacteria and melatonin improves salt tolerance in common bean (Phaseolus vulgaris L.) through ion homeostasis

Publisher Copyright: © 2022, The Author(s).A comprehensive body of scientific evidence indicates that rhizobial bacteria and melatonin enhance salt tolerance of crop plants. The overall goal of this research was to evaluate the ability of Rhizobium leguminoserum bv phaseoli to suppress salinity stress impacts in common bean treated with melatonin. Treatments included bacterial inoculations (inoculated (RI) and non-inoculated (NI)), different salinity levels (non-saline (NS), 4 (S1) and 8 (S2) dS m−1 of NaCl) and priming (dry (PD), melatonin (PM100) and hydro (PH) priming) with six replications in growing media containing sterile sand and perlite (1:1). The results showed that the bacterial strain had the ability to produce indole acetic acid (IAA), ACC deaminase and siderophore. Plants exposed to salinity stress indicated a significant decline in growth, yield, yield components, nitrogen fixation and selective transport (ST), while showed a significant increase in sodium uptake. However, the combination of PM100 and RI treatments by improving growth, photosynthesis rate and nitrogen fixation positively influenced plant performance in saline conditions. The combined treatment declined the negative impacts of salinity by improving the potassium translocation, potassium to sodium ratio in the shoot and root and ST. In conclusion, the combination of melatonin and ACC deaminase producing rhizobium mitigated the negative effects of salinity. This result is attributed to the increased ST and decreased sodium uptake, which significantly reduced the accumulation of sodium ions in shoot.Peer reviewe

Neuroprotective effects of Ocimum basilicum L. var. thyrsiflora on scopolamine- induced non-spatial memory deficits in rats

Pharmacological studies indicated that Ocimum basilicum L. var. thyrsiflora has numerous therapeutic potentials. The aim of this study was to investigate the neuroprotective action of O. basilicum leaf extract against scopolamine-induced non-spatial memory deficits in rats and to determine the changes in mRNA expressions of genes implicated in cognition and neuroprotection. O. basilicum leaves were extracted with 80% ethanol and verified for the presence of rosmarinic acid using high performance liquid chromatography method. Male Wistar rats were treated orally with eitherO. basilicum or the positive control piracetam for 14 days prior to the injection of 0.5 mg/kg scopolamine on the day of the novel object discrimination (NOD) test. Hippocampi were collected at the end of the test. mRNA expression of nicotinic acetylcholine α7 subunit (NA7), muscarinic M1 receptor (M1), neuronal nitric oxide synthase (nNOS), and 5-hydroxytryptamine receptor 3A (HTR3A) genes in the hippocampi were analyzed using qPCR method. The presence of rosmarinic acid in the plant extract was detected at chromatogram peak of Rt=16.891. NOD test results indicated that the lower dose of O. basilicum (200 mg/kg) significantly (p<0.05) reversed scopolamine-induced memory deficits in rats similar to the effects of piracetam. In addition, O. basilicum at the same dose alleviated the increase in mRNA expressions of the NA7, M1, nNOS, and HTR3A genes induced by scopolamine. The present findings suggest that O. basilicum is potentially neuroprotective in preventing memory impairment through alleviation of scopolamine-induced changes in hippocampal mRNA expression implicated in cognition and neuroprotection