## Search

Now showing items 161-170 of 177

#### Refining Phylogenetic Trees Given Additional Data: Algorithms Based on Parsimony

(University of Canterbury. Mathematics and Statistics, 2009)

Given a set X of taxa, a phylogenetic X-tree T that is only partially resolved, and a collection of characters on X, we consider the problem of finding a resolution (refinement) of T that minimizes the parsimony score of ...

#### Partial fields and matroid representation

(University of Canterbury. Mathematics and Statistics., 1996)

A partial field P is an algebraic structure that behaves very much
like a field except that addition is a partial binary operation, that is,
for some a,b Є P, a + b may not be defined. We develop a theory of
matroid ...

#### Computing the minimum number of hybridization events for a consistent evolutionary history

(University of Canterbury. Mathematics and Statistics., 2007)

It is now well-documented that the structure of evolutionary relationships between a set of present-day species is not necessarily tree-like. The reason for this is that reticulation events such as hybridizations mean that ...

#### A 3-approximation algorithm for the subtree distance between phylogenies

(University of Canterbury. Mathematics and Statistics., 2008)

In this paper, we give a (polynomial-time) 3-approximation algorithm for the rooted subtree prune and regraft distance between two phylogenetic trees. This problem is known to be NP-complete and the best previously known ...

#### A Framework for Representing Reticulate Evolution

(University of Canterbury. Mathematics and Statistics., 2005)

Acyclic directed graphs (ADGs) are increasingly being viewed as
more appropriate for representing certain evolutionary relationships, particu-
larly in biology, than rooted trees. In this paper, we develop a framework ...

#### On the Computational Complexity of the Rooted Subtree Prune and Regraft Distance

(University of Canterbury. Mathematics and Statistics., 2004)

The graph-theoretic operation of rooted subtree prune and regraft
is increasingly being used as a tool for understanding and modelling reticu-
lation events in evolutionary biology. In this paper, we show that computing
the ...

#### Nature reserve selection problem: a tight approximation algorithm

(University of Canterbury. Mathematics and Statistics., 2008)

The Nature Reserve Selection Problem is a problem that arises in the context of studying biodiversity conservation.
Subject to budgetary constraints, the problem is to select a set of regions to conserve so that the ...

#### A frequency domain analytical model of an uncontrolled single phase voltage source rectifier

(University of Canterbury. Electrical and Computer Engineering., 2000)

The harmonic currents generated by the single-phase
rectifier are well known. As the levels of these currents become
larger, the use of power conditioners such as shunt active filters to
lower the levels is becoming ...

#### Implementation of Unsteady Sampling Procedures for the Parallel Direct Simulation Monte Carlo Method

(University of Canterbury. Mechanical Engineering., 2008)

An unsteady sampling routine for a general parallel Direct Simulation Monte Carlo
method called PDSC is introduced, allowing the simulation of time-dependent flow
problems in the near continuum range. A post-processing ...

#### Digital Image Elasto-Tomography: Combinatorial and Hybrid Optimization Algorithms for Shape-Based Elastic Property Reconstruction

(University of Canterbury. Mechanical Engineering., 2008)

Results from the application of three nonlinear stiffness reconstruction algorithms to two simple cylindrical geometries are presented in this paper. Finite-element simulated harmonic
motion data with added noise were ...