Computing and Mathematical Sciences Papers
This collection houses research from the Faculty of Computing and Mathematical Sciences at the University of Waikato.
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Robin's inequality for 11free integers
(State University of West Georgia, Charles University, and DIMATIA, 2015)Let σ(n) denote the sum of divisors function, and let ϒ be Euler’s constant. We prove that if there is an n≥5041 for which σ(n)≥eϒn log log n, then n must be divisible by the eleventh power of some prime. 
Coping with design complexity: a conceptual framework for design alternatives and variants
(Springer, 2017)Interaction design processes are characterised by multidisciplinary teamwork and by an interplay of creative, situated and analytical thinking. Although design in the domain of humancomputer interaction has been widely ... 
Intermittency, nonlinear dynamics and dissipation in the solar wind and astrophysical plasmas
(The Royal Society, 2015)An overview is given of important properties of spatial and temporal intermittency, including evidence of its appearance in fluids, magnetofluids and plasmas, and its implications for understanding of heliospheric plasmas. ... 
A conjecture of De Koninck regarding particular square values of the sum of divisors function
(Elsevier Inc, 2014)We study integers n > 1 satisfying the relation σ(n) = γ(n)², where σ(n) and γ(n) are the sum of divisors and the product of distinct primes dividing n, respectively. If the prime dividing a solution n is congruent to 3 ... 
The effect of surface tension on free surface flow induced by a point sink in a fluid of finite depth
(Elsevier Ltd, 2017)Solutions are presented to the problem of steady, axisymmetric flow of an inviscid fluid into a point sink. The fluid is of finite depth and has a free surface. Two numerical schemes, a spectral method and an integral ... 
The role of acromioplasty when repairing rotator cuff tears – no difference in pain or functional outcome at 24 months in a cohort of 2,441 patients
(New Zealand Medical Association, 2017)AIM: The role acromioplasty with rotator cu repair remains unclear. This study aims to test the null hypothesis—that acromioplasty in conjunction with rotator cuff repair has no effect on improvement in pain or shoulder ... 
Modelling loanword success a sociolinguistic quantitative study of Māori loanwords in New Zealand English
(Mouton de Gruyter, 2017)Loanword use has dominated the literature on language contact and its salient nature continues to draw interest from linguists and nonlinguists. Traditionally, loanwords were investigated by means of raw frequencies, which ... 
The effect of irrigation on cadmium, uranium, and phosphorus contents in agricultural soils
(Elsevier, 2017)Cadmium (Cd) is a toxic metal which has accumulated in New Zealand agricultural soils due to phosphate fertilizer application. Understanding the contribution of plant uptake or leaching of Cd to observed Cd losses from ... 
Isotope Tracing of LongTerm Cadmium Fluxes in an Agricultural Soil
(American Chemical Society, 2017)Globally widespread phosphate fertilizer applications have resulted in longterm increases in the concentration of cadmium (Cd) in soils. The accumulation of this biotoxic, and bioaccumulative metal presents problems for ... 
Subcubic trades in Steiner triple systems
(Elsevier Science BV, 2017)We consider the problem of classifying trades in Steiner triple systems such that each block of the trade contains one of three fixed elements. We show that the fundamental building blocks for such trades are 3regular ... 
Critical sets of 2balanced Latin rectangles
(2016)An (m, n, 2)balanced Latin rectangle is an (Formula presented.) array on symbols 0 and 1 such that each symbol occurs n times in each row and m times in each column, with each cell containing either two 0’s, two 1’s or ... 
There are asymptotically the same number of Latin squares of each parity
(Cambridge University Press, 2016)A Latin square is reduced if its first row and column are in natural order. For Latin squares of a particular order n there are four possible different parities. We confirm a conjecture of Stones and Wanless by showing ... 
All for one and one for all: reconciling research and production values at the HathiTrust through userscripting
(IEEE, 2017)This article details a practical technique that safely reconciles the production stability and integrity of the HathiTrust Digital Library (HTDL) with the riskier and potentially disruptive experimental functionalities ... 
Taking a book off the shelf in a virtual library
(IEEE, 2017)We present the results of a smallscale study in which participants interacted with a physical book. Their book selection and book opening gestures provide design insights for the interface to a virtual reality library. 
Big brother is watching you  now in a doubleplusgood way
(IEEE, 2017)This paper reports on the progress made with our X Marks The Spot (XMTS) system. In XMTS we make a fundamental change to the compositing operation in a desktop manager, storing all textdisplay events and their related ... 
Largescale automatic species identification
(Springer, 2017)The crowdsourced Naturewatch GBIF dataset is used to obtain a species classification dataset containing approximately 1.2 million photos of nearly 20 thousand different species of biological organisms observed in their ... 
Adaptive random forests for evolving data stream classification
(Springer, 2017)Random forests is currently one of the most used machine learning algorithms in the nonstreaming (batch) setting. This preference is attributable to its high learning performance and low demands with respect to input ... 
Epibiotic pressure contributes to biofouling invader success
(Nature Publishing Group, 2017)Reduced competition is a frequent explanation for the success of many introduced species. In benthic marine biofouling communities, space limitation leads to high rates of overgrowth competition. Some species can utilise ... 
Detecting sentiment change in Twitter streaming data
(JMLR, 2011)MOATweetReader is a realtime system to read tweets in real time, to detect changes, and to find the terms whose frequency changed. Twitter is a microblogging service built to discover what is happening at any moment in ... 
Accelerating the XGBoost algorithm using GPU computing
(2017)We present a CUDAbased implementation of a decision tree construction algorithm within the gradient boosting library XGBoost. The tree construction algorithm is executed entirely on the graphics processing unit (GPU) and ...