556 research outputs found
On the efficiency of a dedicated LMA for multicast traffic distribution in PMIPv6 domains
IP multicast allows the efficient support of group communication services by reducing the number of IP flows needed for such communication. The increasing generalization in the use of multicast has also triggered the need for supporting IP multicast in mobile environments. Proxy Mobile IPv6 (PMIPv6) is a network-based mobility management solution, where the functionality to support the terminal movement resides in the network. Recently, a baseline solution has been adopted for multicast support in PMIPv6. Such base solution has inefficiencies in multicast routing because it may require multiple copies of a single stream to be received by the same access gateway. Nevertheless, there is an alternative solution to support multicast in PMIPv6 that avoids this issue. This paper evaluates by simulation the scalability of both solutions under realistic conditions, and provides an analysis of the sensitivity of the two proposals against a number of parameters
OKpi: All-KPI Network Slicing Through Efficient Resource Allocation
Networks can now process data as well as transporting it; it follows that
they can support multiple services, each requiring different key performance
indicators (KPIs). Because of the former, it is critical to efficiently
allocate network and computing resources to provide the required services, and,
because of the latter, such decisions must jointly consider all KPIs targeted
by a service. Accounting for newly introduced KPIs (e.g., availability and
reliability) requires tailored models and solution strategies, and has been
conspicuously neglected by existing works, which are instead built around
traditional metrics like throughput and latency. We fill this gap by presenting
a novel methodology and resource allocation scheme, named OKpi, which enables
high-quality selection of radio points of access as well as VNF (Virtual
Network Function) placement and data routing, with polynomial computational
complexity. OKpi accounts for all relevant KPIs required by each service, and
for any available resource from the fog to the cloud. We prove several
important properties of OKpi and evaluate its performance in two real-world
scenarios, finding it to closely match the optimum
Inter-Slice Mobility Management in 5G: Motivations, Standard Principles, Challenges and Research Directions
Mobility management in a sliced 5G network introduces new and complex
challenges. In a network-sliced environment, user mobility has to be managed
not only among different base stations or access technologies, but also among
different slices. This motivates the need for new mobility management
solutions, which, by convention are required to be standards-compliant. This
article, presented as a tutorial, focuses on the problem of inter-slice
mobility from the perspective of 3GPP standards for 5G. A detailed overview of
the relevant 3GPP standard principles is provided. Accordingly, the key
technical gaps, challenges and the corresponding research directions are
identified towards achieving seamless inter-slice mobility within the current
3GPP network slicing framework
Exercises using a touchscreen tablet application improved functional ability more than an exercise program prescribed on paper in people after surgical carpal tunnel release: a randomised trial
Question: In people who have undergone surgical carpal tunnel release, do sensorimotor-based exercises performed on the touchscreen of a tablet device improve outcomes more than a conventional home exercise program prescribed on paper? Design: Randomised, parallel-group trial with concealed allocation, assessor blinding, and intention-to-treat analysis. Participants: Fifty participants within 10 days of surgical carpal tunnel release. Intervention: Each participant was prescribed a 4-week home exercise program. Participants in the experimental group received the ReHand tablet application, which administered and monitored exercises via the touchscreen. The control group was prescribed a home exercise program on paper, as is usual practice in the public hospital system. Outcome measures: The primary outcome was functional ability of the hand, reported using the shortened form of the Disabilities of the Arm, Shoulder and Hand (QuickDASH) questionnaire. Secondary outcomes were grip strength, pain intensity measured on a 10-cm visual analogue scale, and dexterity measured with the Nine-Hole Peg Test. Outcomes were measured by a blinded assessor at baseline and at the end of the 4-week intervention period. Results: At Week 4, functional ability improved significantly more in the experimental group than the control group (MD –21, 95% CI –33 to –9) on the QuickDASH score (0 to 100). Although the mean estimates of effect on the secondary outcome also all favoured the experimental group, none reached statistical significance: grip strength (MD 5.6 kg, 95% CI –0.5 to 11.7), pain (MD –1.4 cm, 95% CI –2.9 to 0.1), and dexterity (MD –1.3 seconds, 95% CI –3.7 to 1.1). Conclusion: Use of the ReHand tablet application for early rehabilitation after carpal tunnel release is more effective in the recovery of functional ability than a conventional home exercise program. It remains unclear whether there are any benefits in grip strength, pain or dexterity. Trial registration: ACTRN12618001887268
An approach to phenotypic analysis and environmental variability. The examples of the genera Dianthus L. and Lotus L. in the north of Portugal
The analysis of the correlation between phenotypic plasticity and environmental variability has been very useful to describe the morphologic responses of individuals to environmental factors affecting them (in the present contribution the altitudinal variation), from a genecological perpective. However, the literature shows that the studies in this area have had a monospecific or monogeneric use. As a consequence, intergeneric comparative descriptions have not been possible. In the present work we propose an analytical method to compare the morphological expressivity of individuals included in the genera Dianthus and Lotus from the north of Portugal by means of a contingency matrix. This matrix was elaborated on the basis of amplitude parameters, in order to describe the variability present
in the basic matrix of each genus studied. The results pointed out the existence of opposite phenotypic behaviours dependent on the altitudinal variation, thus indicating the importance of the analysis between different groups of taxa as a reference for the comparison
of their morphological expressivities
Molecular characterization of retinal stem cells and their niches in adult zebrafish
BACKGROUND: The persistence in adult teleost fish of retinal stem cells that exhibit all of the features of true 'adult stem cells' – self-renewal, multipotency, and the capacity to respond to injury by mitotic activation with the ability to regenerate differentiated tissues – has been known for several decades. However, the specialized cellular and molecular characteristics of these adult retinal stem cells and the microenvironmental niches that support their maintenance in the differentiated retina and regulate their activity during growth and regeneration have not yet been elucidated. RESULTS: Our data show that the zebrafish retina has two kinds of specialized niches that sustain retinal stem cells: 1) a neuroepithelial germinal zone at the interface between neural retina and ciliary epithelium, called the ciliary marginal zone (CMZ), a continuous annulus around the retinal circumference, and 2) the microenvironment around some Müller glia in the differentiated retina. In the uninjured retina, scattered Müller glia (more frequently those in peripheral retina) are associated with clusters of proliferating retinal progenitors that are restricted to the rod photoreceptor lineage, but following injury, the Müller-associated retinal progenitors can function as multipotent retinal stem cells to regenerate other types of retinal neurons. The CMZ has several features in common with the neurogenic niches in the adult mammalian brain, including access to the apical epithelial surface and a close association with blood vessels. Müller glia in the teleost retina have a complex response to local injury that includes some features of reactive gliosis (up-regulation of glial fibrillary acidic protein, GFAP, and re-entry into the cell cycle) together with dedifferentiation and re-acquisition of phenotypic and molecular characteristics of multipotent retinal progenitors in the CMZ (diffuse distribution of N-cadherin, activation of Notch-Delta signaling, and expression of rx1, vsx2/Chx10, and pax6a) along with characteristics associated with radial glia (expression of brain lipid binding protein, BLBP). We also describe a novel specific marker for Müller glia, apoE. CONCLUSION: The stem cell niches that support multi-lineage retinal progenitors in the intact, growing and regenerating teleost retina have properties characteristic of neuroepithelia and neurogenic radial glia. The regenerative capacity of the adult zebrafish retina with its ability to replace lost retinal neurons provides an opportunity to discover the molecular regulators that lead to functional repair of damaged neural tissue
COTORRA: COntext-aware Testbed fOR Robotic Applications
Edge & Fog computing have received considerable attention as promising
candidates for the evolution of robotic systems. In this letter, we propose
COTORRA, an Edge & Fog driven robotic testbed that combines context information
with robot sensor data to validate innovative concepts for robotic systems
prior to being applied in a production environment. In lab/university, we
established COTORRA as an easy applicable and modular testbed on top of
heterogeneous network infrastructure. COTORRA is open for pluggable robotic
applications. To verify its feasibility and assess its performance, we ran set
of experiments that show how autonomous navigation applications can achieve
target latencies bellow 15ms or perform an inter-domain (DLT) federation within
19 seconds.Comment: 4 pages, 4 figures, submitted to IEEE Communications Letter
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