Analysis of Network Parameters Influencing Performance of Hybrid Multimedia Networks

Multimedia networks is an emerging subject that currently attracts the attention of research and industrial communities. This environment provides new entertainment services and business opportunities merged with all well-known network services like VoIP calls or file transfers. Such a heterogeneous system has to be able satisfy all network and end-user requirements which are increasing constantly. Therefore the simulation tools enabling deep analysis in order to find the key performance indicators and factors which influence the overall quality for specific network service the most are highly needed. This paper provides a study on the network parameters like communication technology, routing protocol, QoS mechanism, etc. and their effect on the performance of hybrid multimedia network. The analysis was performed in OPNET Modeler environment and the most interesting results are discussed at the end of this pape

Performance Assessment of Reinforcement Learning Policies for Battery Lifetime Extension in Mobile Multi-RAT LPWAN Scenarios

Considering the dynamically changing nature of the radio propagation environment, the envisioned battery lifetime of the end device (ED) for massive machine-type communication (mMTC) stands for a critical challenge. As the selected radio technology bounds the battery lifetime, the possibility of choosing among several low-power wide-area (LPWAN) technologies integrated at a single ED may dramatically improve its lifetime. In this paper, we propose a novel approach of battery lifetime extension utilizing reinforcement learning (RL) policies. Notably, the system assesses the radio environment conditions and assigns the appropriate rewards to minimize the overall power consumption and increase reliability. To this aim, we carry out extensive propagation and power measurements campaigns at the city-scale level and then utilize these results for composing real-life use-cases for static and mobile deployments. Our numerical results show that RL-based techniques allow for a noticeable increase in EDs’ battery lifetime when operating in multi-RAT mode. Furthermore, out of all considered schemes, the performance of the weighted average policy shows the most consistent results for both considered deployments. Specifically, all RL policies can achieve 90 % of their maximum gain during the initialization phase for the stationary EDs while utilizing less than 50 messages. Considering the mobile deployment, the improvements in battery lifetime could reach 200 %.acceptedVersionPeer reviewe

Hands-On Experience with UWB : Angle of Arrival Accuracy Evaluation in Channel 9

This paper evaluates IEEE 802.15.4z standard- compliant NXP SR040 and SR150 chips in Angle of Arrival (AoA) capabilities in Channel 9 (7.737—8.237 GHz) of the Ultra-WideBand (UWB) spectrum. Due to the shorter wavelength, higher frequencies may encounter certain limitations when it comes to harsh environments, as more reflections and multipath propagation can occur. Furthermore, they also can be affected by their enclosure used to protect the electronics in such an environment, which needs to be taken into account during product design. This work presents the results of the evaluation measurement scenario relatable to real-life use cases and concludes potentially valuable insight important for consideration when creating a new UWB product. Besides a basic overview of the theoretical estimation of AoA by Time Difference of Arrival (TDoA) and Phase Difference of Arrival (PDoA), and the evaluation of the corresponding results, the main contribution is the repeatable topology considered for the conducted measurements. The presented results allow vendors to compare their solutions with the various radio chips or antenna configurations.acceptedVersionPeer reviewe

Optimizing NB-IoT Communication Patterns for Permanently Connected mMTC Devices

The new types of industry-driven applications that need to be supported by low-power wide-area networks (LP-WANs), such as remote control or metering of devices within the massive machine-type infrastructures (e.g., Smart Grids), require a permanent connection to the remote server. In addition, there is also a shift in the communication paradigm, as the user equipment (UE) nodes are queried in regular and frequent intervals. Notably, the presence of this type of traffic may drastically deteriorate the performance of LPWAN technologies initially developed to support conventional use-cases characterized by non-synchronized transmissions. Though none of the LPWAN technologies is inherently designed to handle such demanding communication patterns, the narrowband Internet of things (NB-IoT) still stands for the best candidate as it operates within the license frequency spectrum. To optimize the delay performance of both types of traffic coexisting at the NB-IoT air interface, we propose an approach based on spreading the message transmission time instants of regular and stochastic traffic. We show an optimal value of the spreading interval minimizing the message transmission delay of regular traffic and propose a mathematical model to estimate its value. By parameterizing the model using a detailed measurements campaign of NB-IoT, we show that the optimal value of spreading interval and associated mean message delay is a linear function of the number of UEs. We report these values for a wide range of UEs in the coverage area of the NB-IoT base station and show that conventional stochastic traffic does not influence regular traffic performance.acceptedVersionPeer reviewe

Playfulness and progression in technology-enhanced social experiences between nearby strangers

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Performance Analysis of Different LoRaWAN Frequency Bands for mMTC Scenarios

The possibility of utilizing different frequencies for the LoRaWAN is a key component which, together with the other parameters, i.e., (i) bandwidth, (ii) spreading factor, (iii) coding rate, and (iv) transmission power, defines the communication performance. In this paper, we present the substantive im- provements for both the end devices and the radio access network (gateways) to enhance the data rates and decrease the communication latency. The implementation changes were made for the publicly available LoRaWAN module “signetlabdei” for Network Simulator 3. Utilizing the frequency 2.4GHz, the transmission time in the LoRaWAN network has improved by 80 % decreasing from 75 ms to 14 ms. The frequency 2.4 GHz for the EU region also showed the best performance due to the extended bandwidth (transmission success above 90%) in the case of the mMTC scenario with thousands of devices deployed. Together with the updated LoRaWAN module, the reported results are expected to serve as a building block for mMTC- oriented simulation scenarios.acceptedVersionPeer reviewe

Distinct genetic architecture underlies the emergence of sleep loss and prey-seeking behavior in the Mexican cavefish

Sleep is characterized by extended periods of quiescence and reduced responsiveness to sensory stimuli. Animals ranging from insects to mammals adapt to environments with limited food by suppressing sleep and enhancing their response to food cues, yet little is known about the genetic and evolutionary relationship between these processes. The blind Mexican cavefish, Astyanax mexicanus is a powerful model for elucidating the genetic mechanisms underlying behavioral evolution. A. mexicanus comprises an extant ancestral-type surface dwelling morph and at least five independently evolved cave populations. Evolutionary convergence on sleep loss and vibration attraction behavior, which is involved in prey seeking, have been documented in cavefish raising the possibility that enhanced sensory responsiveness underlies changes in sleep. We established a system to study sleep and vibration attraction behavior in adult A. mexicanus and used high coverage quantitative trait loci (QTL) mapping to investigate the functional and evolutionary relationship between these traits. Analysis of surface-cave F2 hybrid fish and an outbred cave population indicates that independent genetic factors underlie changes in sleep/locomotor activity and vibration attraction behavior. High-coverage QTL mapping with genotyping-by-sequencing technology identify two novel QTL intervals that associate with locomotor activity and include the narcolepsy-associated tp53 regulating kinase. These QTLs represent the first genomic localization of locomotor activity in cavefish and are distinct from two QTLs previously identified as associating with vibration attraction behavior. Taken together, these results localize genomic regions underlying sleep/locomotor and sensory changes in cavefish populations and provide evidence that sleep loss evolved independently from enhanced sensory responsiveness.https://doi.org/10.1186/s12915-015-0119-

Receptor Tyrosine Kinases Activate Canonical WNT/β-Catenin Signaling via MAP Kinase/LRP6 Pathway and Direct β-Catenin Phosphorylation

Receptor tyrosine kinase signaling cooperates with WNT/β-catenin signaling in regulating many biological processes, but the mechanisms of their interaction remain poorly defined. We describe a potent activation of WNT/β-catenin by FGFR2, FGFR3, EGFR and TRKA kinases, which is independent of the PI3K/AKT pathway. Instead, this phenotype depends on ERK MAP kinase-mediated phosphorylation of WNT co-receptor LRP6 at Ser1490 and Thr1572 during its Golgi network-based maturation process. This phosphorylation dramatically increases the cellular response to WNT. Moreover, FGFR2, FGFR3, EGFR and TRKA directly phosphorylate β-catenin at Tyr142, which is known to increase cytoplasmic β-catenin concentration via release of β-catenin from membranous cadherin complexes. We conclude that signaling via ERK/LRP6 pathway and direct β-catenin phosphorylation at Tyr142 represent two mechanisms used by various receptor tyrosine kinase systems to activate canonical WNT signaling