1,721,028 research outputs found
F-Chord: Improved Uniform Routing on Chord
No full textWe propose a family of novel Chord-based P2P schemes retaining all positive aspects that made Chord a popu- lar topology for routing in P2P networks. The schemes, based on the Fibonacci number system, allow to simul- taneously improve on the maximum/average number of hops for lookups and the routing table size per node
Optimizing the finger table in Chord-like DHTs
No full textThe Chord protocol is the best known example of implementation of logarithmic complexity routing for
structured peer-to-peer networks. Its routing algorithm, however, does not provide an optimal trade-off
between resources exploited (the size of the ‘finger table’) and performance (the average or worst-case
number of hops to reach destination). Cordasco et al. showed that a finger table based on Fibonacci
distances provides lower number of hops with fewer table entries. In this paper we generalize this result,
showing how to construct an improved finger table when the objective is to reduce the number of hops,
possibly at the expense of an increased size of the finger table. Our results can also be exploited to
guarantee low routing time in case a fraction of nodes fails
Crystal chemcal study of R-3c natural oxides along the eskolaite - karelianite - hematite (Cr2O3 -V2O3-Fe2O3) join
No full textSix natural crystals from the Sludyanka crystalline complex belonging to the eskolaite (Cr2O3)–
karelianite (V2O3)hematite (Fe2O3) solid solution were studied by means of X-ray diffraction and
electron microprobe. The Fe3+-poor samples show a general increase in a and c cell parameters with
increasing mean cationic radius (MCR), consistent with that shown by the synthetic crystals along the
eskolaite–karelianite join. The Fe3+-richer sample deviates significantly from the behaviour shown by
the Fe3+-poor ones, similar to synthetic andnatural hematites; with increasing MCR, the a and c cell
parameters increase linearly along the eskolaite–karelianite join. However, for the samples rich in Fe3+,
from karelianite to hematite, a shows a slightly steeper slope whereas the c parameter decreases
strongly. The octahedral distortion increases slightly as a function of MCR along the eskolaite–
karelianite join, whereas it increases markedly for Fe3+-rich samples. The evolution of the octahedral
edges and of the octahedral distortions as a function of MCR are responsible for the behaviour of the
unit-cell parameters along the eskolaite–karelianite–hematite join
Chronic intractable lumbosacral radicular pain, is there a remedy? Pulsed radiofrequency treatment and volumetric modifications of the lumbar dorsal root ganglia
No full textPurpose Evaluation of clinical and radiological effects of the therapeutic outcome of CT-guided pulsed radiofrequency (PRF)
treatment adjacent to the lumbar dorsal root ganglion (DRG) for patients with chronic intractable lumbosacral radicular pain
in a single-center prospective longitudinal study in order to evaluate predictive factors of safety and therapeutic success.
Materials and methods Thirty patients, from 2016 to 2018, were enrolled (age: 42–80 aa, 66.7% men and 33.3% females)
with low back pain, lumbosciatalgia and/or lumbocruralgia, resistant to previous medical and physical treatments for a period
not < 3 months, failure of surgical and chemiodiscolysis with ozone oxygen therapy. Each patient was subjected to a clinical
evaluation (antalgic walking, sensitive deficit, interviews with specific questionnaires: ODI, RDQ,VAS) and to a radiological
evaluation with MRI examination, before and 30 days after the CT-guided PRF treatment. Measurements of the thickness
of the involved and not involved DRG were taken using common postprocessing software of MRI examinations in order to
have measurement parameters for comparison. We analyzed the clinical course using the paired samples T test in order to
evaluate modification for each clinical and radiological parameter (statistical significance p < 0.05).
Results Significant improvements of the clinical outcomes with a good resolution of the pain symptoms (VAS evaluation: The
score fell from 68.47 to 39.17 with a difference of 29.3 and a reduction of the 42.79% in the perceived pain, p = 0.00000152).
The thickness of DRG falls from an average media of 0.586–0.448 cm (p = 0.000085), with a difference of 0.138 cm and a
percentage reduction of 22.30%.
Conclusions PRF treatment of the DRG may be considered for patients with chronic severe lumbosacral radicular pain
refractory to conventional medical management when other noninvasive or surgical procedures fail. It is minimally invasive,
inexpensive and simple to perform with no complications
Non-uniform deterministic routing on F-Chord(α)
No full textIn this paper, we present a family of novel P2P routing schemes based on Chord (and its variation F-Chord(α) that trades off uniformity with efficiency without using any additional overhead. We prove that H-F-Chord(α)'s routing is more efficient than in F-Chord(α) in terms of its average path length that is O(log n/ log log n). We also show, by simulations, that H-F-Chord(α) is more efficient than the corresponding F-Chord(α) by a percentage that goes from 15% to 22% even for small n
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