335 research outputs found
Exploiting the Synergy Between Gossiping and Structured Overlays
In this position paper we argue for exploiting the synergy between gossip-based algorithms and structured overlay networks (SON). These two strands of research have both aimed at building fault-tolerant, dynamic, self-managing, and large-scale distributed systems. Despite the common goals, the two areas have, however, been relatively isolated. We focus on three problem domains where there is an untapped potential of using gossiping combined with SONs. We argue for applying gossip-based membership for ring-based SONs---such as Chord and Bamboo---to make them handle partition mergers and loopy networks. We argue that small world SONs---such as Accordion and Mercury---are specifically well-suited for gossip-based membership management. The benefits would be better graph-theoretic properties. Finally, we argue that gossip-based algorithms could use the overlay constructed by SONs. For example, many unreliable broadcast algorithms for SONs could be augmented with anti-entropy protocols. Similarly, gossip-based aggregation could be used in SONs for network size estimation and load-balancing purposes
Possibility of primordial black holes as the source of gravitational wave events in the advanced LIGO detector
The analysis of gravitational Wave (GW) data from advanced LIGO provides the
mass of each companion of binary black holes as the source of GWs. The mass of
events corresponding to the binary black holes from GW is above M
which is much larger than the mass of astrophysical black holes detected by
x-ray observations. In this work, we examine primordial black holes (PBHs) as
the source of LIGO events. Assuming that of the dark matter is made of
PBHs, we estimate the rate at which these objects make binaries, merge, and
produce GWs as a function of redshift. The gravitational lensing of GWs by PBHs
can also enhance the amplitude of the strain. We simulate GWs sourced by binary
PBHs, with the detection threshold of for both Livingston and Hanford
detectors. For the log-normal mass function of PBHs, we generate the expected
distribution of events, compare our results with the observed events, and find
the best value of the mass function parameters (i.e., and
) in the log-normal mass function. Comparing the expected number of
events with the number of observed ones rules out the present-Universe binary
formation PBH scenario as the candidate for the source of GW events detected by
LIGO.Comment: Final published versio
Braneworld inflation
We discuss various realizations of the four dimensional braneworld inflation
in warped geometries of string theory. In all models the inflaton field is
represented by a Dp probe brane scalar specifying its position in the warped
throat of the compactification manifold. We study existing inflationary throat
local geometries, and construct a new example. The inflationary brane is either
a D3- or a D5-brane of type IIB string theory. In the latter case the
inflationary brane is wrapping a two-cycle of the compactification manifold. We
discuss some phenomenological aspects of the model where slow-roll conditions
are under computational control.Comment: 31 pages + 6 figures, v2: published PRD versio
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