1,363 research outputs found
3-dimensional Channel Routing
Consider two parallel planar grids of size
w
Ă
n
. The vertices of these grids
are called terminals and pairwise disjoint subsets of termi
nals are called nets. We
aim at routing all nets in a cubic grid between the two layers h
olding the terminals.
However, to ensure solvability, it is allowed to introduce a
n empty row/column be-
tween every two consecutive rows/columns containing the te
rminals (in both grids).
Hence the routing is to be realized in a cubic grid of size 2
n
Ă
2
w
Ă
h
. The objective
is to minimize the height
h
. In this paper we generalize previous results of Recski
and Szeszl Ìer [10] and show that every problem instance is so
lvable in polynomial
time with height
h
=
O
(max(
n, w
)). This linear bound is best possible (apart from
a constant factor)
Protection and restoration algorithms for WDM optical networks
Currently, Wavelength Division Multiplexing (WDM) optical networks play a major role in supporting the outbreak in demand for high bandwidth networks driven by the Internet. It can be a catastrophe to millions of users if a single optical fiber is somehow cut off from the network, and there is no protection in the design of the logical topology for a restorative mechanism. Many protection and restoration algorithms are needed to prevent, reroute, and/or reconfigure the network from damages in such a situation. In the past few years, many works dealing with these issues have been reported. Those algorithms can be implemented in many ways with several different objective functions such as a minimization of protection path lengths, a minimization of restoration times, a maximization of restored bandwidths, etc. This thesis investigates, analyzes and compares the algorithms that are mainly aimed to guarantee or maximize the amount of remaining bandwidth still working over a damaged network. The parameters considered in this thesis are the routing computation and implementation mechanism, routing characteristics, recovering computation timing, network capacity assignment, and implementing layer. Performance analysis in terms of the restoration efficiency, the hop length, the percentage of bandwidth guaranteed, the network capacity utilization, and the blocking probability is conducted and evaluated
A Design Strategy for Deadlock-Free Concurrent Systems
When building concurrent systems, it would be useful to have a collection of reusable processes
to perform standard tasks. However, without knowing certain details of the inner workings of
these components, one can never be sure that they will not cause deadlock when connected to
some particular network.
Here we describe a hierarchical method for designing complex networks of communicating
processeswhich are deadlock-free.We use this to define a safe and simple method for specifying
the communication interface to third party software components. This work is presented using
the CSP model of concurrency and the occam2.1 programming language
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