Browsing Research Articles (Mathematical Sciences) by Title
Now showing items 120 of 65

The asymptotic number of binary codes and binary matroids
(Society for Industrial and Applied Mathematics (SIAM), 200608)The asymptotic number of nonequivalent binary ncodes is determined. This is also the asymptotic number of nonisomorphic binary matroids on n elements. 
Benchmarking multirate codon models
(Public Library of Science, 20100721)The single rate codon model of nonsynonymous substitution is ubiquitous in phylogenetic modeling. Indeed, the use of a nonsynonymous to synonymous substitution rate ratio parameter has facilitated the interpretation of ... 
Calculating the output distribution of stack filters that are erosiondilation cascades, in particular LULUfilters
(Cornell University Library, 2011)ENGLISH ABSTRACT: Two procedures to compute the output distribution 0S of certain stack filters S (so called erosiondilation cascades) are given. One rests on the disjunctive normal form of S and also yields the rank ... 
Canonical trees, compact prefixfree codes, and sums of unit fractions: a probabilistic analysis
(SIAM, 2015)For fixed t ≥ 2, we consider the class of representations of 1 as a sum of unit fractions whose denominators are powers of t, or equivalently the class of canonical compact tary Huffman codes, or equivalently rooted ... 
Capturing spiral radial growth of conifers using the superellipse to model treering geometric shape
(Frontiers Media, 2015)Treerings are often assumed to approximate a circular shape when estimating forest productivity and carbon dynamics. However, tree rings are rarely, if ever, circular, thereby possibly resulting in under or overestimation ... 
Coauthorship networks in South African chemistry and mathematics
(Academy of Science for South Africa, 2008)Coauthorship networks are graphs in which the nodes of the graph represent authors and two authors are connected by an edge if they have written one or more papers together. When applied to the authorship of scholarly ... 
Codon test : modeling amino acid substitution preferences in coding sequences
(PLOS Computational Biology, 201008)Codon models of evolution have facilitated the interpretation of selective forces operating on genomes. These models, however, assume a single rate of nonsynonymous substitution irrespective of the nature of amino acids ... 
Combining uncertainties in a court of law using Bayesian networks
(Obiter Law Journal: Nelson Mandela Metropolitan University (NMMU), Faculty of Law, 2017)People generally have difficulty dealing with the counterintuitive notion of probability, and therefore they often misunderstand aspects of uncertainty. This is particularly significant in a court of law when for example ... 
Compactly generating all satisfying truth assignments of a horn formula
(Delft University in cooperation with IOS Press, 201201)ENGLISH ABSTRACT: While it was known that all models of a Horn formula can be generated in outputpolynomial time, here we present an explicit algorithm as opposed to the rather vague oraclescheme suggested in the proof ... 
A comparison of elasticities of viral levels to specific immune response mechanisms in human immunodeficiency virus infection
(BioMed Central, 201410)Background The presence of an asymptomatic phase in an HIV infection indicates that the immune system can partially control the infection. Determining the immune mechanisms that contribute significantly to the partial ... 
Computational and theoretical analysis of human diseases associated with infectious pathogens
(Hindawi, 2015)Mathematical models and computer simulations are useful experimental tools for building and testing theories, assessing quantitative conjectures, answering specific questions, determining sensitivities to changes in parameter ... 
Computing the output distribution of a stack filter from the DNF of its positive Boolean function
(Cornell University Library, 2010)ENGLISH ABSTRACT: The majority of nonlinear filters used in practise are stack filters. An algorithm is presented which calculates the output distribution of an arbitrary stack filter S from the disjunctive normal form ... 
Computing various types of lattices freely generated by posets
(Edizioni CERFIM Centro di Ricerche in Fisica e MatematicaResearch Center for Mathematics and Physics  Locarno  Switzerland, 2000)see item for abstract 
Correcting the bias of empirical frequency parameter estimators in codon models
(Public Library of Science  PLOS, 201007)Markov models of codon substitution are powerful inferential tools for studying biological processes such as natural selection and preferences in amino acid substitution. The equilibrium character distributions of these ... 
Decomposing the hypercube Qn into n isomorphic edgedisjoint trees
(Elsevier, 201202)The problem of finding edgedisjoint trees in a hypercube arises for example in the context of parallel computing [3]. Independently of applications it is of high aesthetic appeal. The hypercube of dimension n, denoted ... 
Detecting individual sites subject to episodic diversifying selection
(Public Library of Science, 20120702)The imprint of natural selection on protein coding genes is often difficult to identify because selection is frequently transient or episodic, i.e. it affects only a subset of lineages. Existing computational techniques, ... 
The development of a spatiotemporal model for water hyacinth biological control strategies
(University of Georgia, 2016)A reactiondiffusion model for a temporally variable and spatially heterogeneous environment is developed to mathematically describe the spatial dynamics of water hyacinth and the interacting populations of the various ... 
Effects of agricultural intensification on ability of natural enemies to control aphids
(Springer Nature, 20150126)Agricultural intensification through increasing fertilization input and cropland expansion has caused rapid loss of seminatural habitats and the subsequent loss of natural enemies of agricultural pests. It is however extremely ... 
Entropy generation in a couple stress fluid flow through a vertical channel filled with saturated porous media
(MDPI, 20131025)The present work investigates numerically the inherent irreversibility in a steady flow of a couple stress fluid through a vertical channel packed with saturated porous substances. The First and Second Laws of Thermodynamics ... 
Francis Guthrie : a colourful life
(Springer, 201209)In 1852, in London, Francis Guthrie posed the question of colouring a map with four colours only, the question that eventually became known as the Four Colour Problem. The problem is famous, but what else do we know of ...