9,078 research outputs found
Honk if you love book reviews! Looking back at 10 years of book reviews in The Goose
This editorial looks back at 10 years of book reviews in The Goose to consider how book reviews have helped to shape the landscape of Canadian ecocriticism. It also looks forward to suggest how book reviews will continue to be an integral part of The Goose
The Environmental Humanities in a Post-Truth World
Editorial introduction to The Goose Volume 15, Issue 2 (2017)
Responding to a Racist Climate: An Editorial
Editorial introduction to The Goose Volume 16, Issue 1 (2017)
Editor\u27s Notebook
Editorial introduction to The Goose Volume 15, Issue 1 (2016)
Planar L-Drawings of Directed Graphs
We study planar drawings of directed graphs in the L-drawing standard. We
provide necessary conditions for the existence of these drawings and show that
testing for the existence of a planar L-drawing is an NP-complete problem.
Motivated by this result, we focus on upward-planar L-drawings. We show that
directed st-graphs admitting an upward- (resp. upward-rightward-) planar
L-drawing are exactly those admitting a bitonic (resp. monotonically
increasing) st-ordering. We give a linear-time algorithm that computes a
bitonic (resp. monotonically increasing) st-ordering of a planar st-graph or
reports that there exists none.Comment: Appears in the Proceedings of the 25th International Symposium on
Graph Drawing and Network Visualization (GD 2017
From BGP to RTT and Beyond: Matching BGP Routing Changes and Network Delay Variations with an Eye on Traceroute Paths
Many organizations have the mission of assessing the quality of broadband
access services offered by Internet Service Providers (ISPs). They deploy
network probes that periodically perform network measures towards selected
Internet services. By analyzing the data collected by the probes it is often
possible to gain a reasonable estimate of the bandwidth made available by the
ISP. However, it is much more difficult to use such data to explain who is
responsible of the fluctuations of other network qualities. This is especially
true for latency, that is fundamental for several nowadays network services. On
the other hand, there are many publicly accessible BGP routers that collect the
history of routing changes and that are good candidates to be used for
understanding if latency fluctuations depend on interdomain routing.
In this paper we provide a methodology that, given a probe that is located
inside the network of an ISP and that executes latency measures and given a set
of publicly accessible BGP routers located inside the same ISP, decides which
routers are best candidates (if any) for studying the relationship between
variations of network performance recorded by the probe and interdomain routing
changes. We validate the methodology with experimental studies based on data
gathered by the RIPE NCC, an organization that is well-known to be independent
and that publishes both BGP data within the Routing Information Service (RIS)
and probe measurement data within the Atlas project
The Partial Visibility Representation Extension Problem
For a graph , a function is called a \emph{bar visibility
representation} of when for each vertex , is a
horizontal line segment (\emph{bar}) and iff there is an
unobstructed, vertical, -wide line of sight between and
. Graphs admitting such representations are well understood (via
simple characterizations) and recognizable in linear time. For a directed graph
, a bar visibility representation of , additionally, puts the bar
strictly below the bar for each directed edge of
. We study a generalization of the recognition problem where a function
defined on a subset of is given and the question is whether
there is a bar visibility representation of with for every . We show that for undirected graphs this problem
together with closely related problems are \NP-complete, but for certain cases
involving directed graphs it is solvable in polynomial time.Comment: Appears in the Proceedings of the 24th International Symposium on
Graph Drawing and Network Visualization (GD 2016
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