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Robust Circle Detection Using Harmony Search

Jaco Fourie
2017 Journal of Optimization  
Automatic circle detection is an important element of many image processing algorithms. Traditionally the Hough transform has been used to find circular objects in images but more modern approaches that make use of heuristic optimisation techniques have been developed. These are often used in large complex images where the presence of noise or limited computational resources make the Hough transform impractical. Previous research on the use of the Harmony Search (HS) in circle detection showed
more » ... hat HS is an attractive alternative to many of the modern circle detectors based on heuristic optimisers like genetic algorithms and simulated annealing. We propose improvements to this work that enables our algorithm to robustly find multiple circles in larger data sets and still work on realistic images that are heavily corrupted by noisy edges.
doi:10.1155/2017/9710719 fatcat:24jnqngfojdfhajyrfssjsre7q

Photogrammetry for assessment of pasture biomass

Kathryn Wigley, Jennifer L. Owens, Matthias Westerschulte, Paul Riding, Jaco Fourie, Armin Werner
2019 Journal of New Zealand Grasslands  
New tools are required to provide estimates of pasture biomass as current methods are time consuming and labour intensive. This proof-of-concept study tested the suitability of photogrammetry to estimate pasture height in a grazed dairy pasture. Images were obtained using a digital camera from one site on two separate occasions (May and June 2017). Photogrammetry-derived pasture height was estimated from digital surface models created using the photos. Pasture indices were also measured using
more » ... o currently available methods: a Rising Plate Meter (RPM), and Normalised Difference Vegetation Index (NDVI). Empirical pasture biomass measurements were taken using destructive sampling after all other measurements were made, and were used to evaluate the accuracy of the estimates from each method. There was a strong linear relationship between photogrammetry-derived plant height and actual biomass (R2=0.92May and 0.78June) and between RPM and actual biomass (R2=0.91May and 0.78June). The relationship between NDVI and actual biomass was relatively weaker (R2=0.65May and 0.66June). Photogrammetry could be an efficient way to measure pasture biomass with an accuracy comparable to that of the RPM but further work is required to confirm these preliminary findings.
doi:10.33584/jnzg.2019.81.394 fatcat:in6uevgu2vbxfjk7abkxiwz7qy

Generalised Adaptive Harmony Search: A Comparative Analysis of Modern Harmony Search

Jaco Fourie, Richard Green, Zong Woo Geem
2013 Journal of Applied Mathematics  
Harmony search (HS) was introduced in 2001 as a heuristic population-based optimisation algorithm. Since then HS has become a popular alternative to other heuristic algorithms like simulated annealing and particle swarm optimisation. However, some flaws, like the need for parameter tuning, were identified and have been a topic of study for much research over the last 10 years. Many variants of HS were developed to address some of these flaws, and most of them have made substantial improvements.
more » ... In this paper we compare the performance of three recent HS variants: exploratory harmony search, self-adaptive harmony search, and dynamic local-best harmony search. We compare the accuracy of these algorithms, using a set of well-known optimisation benchmark functions that include both unimodal and multimodal problems. Observations from this comparison led us to design a novel hybrid that combines the best attributes of these modern variants into a single optimiser called generalised adaptive harmony search.
doi:10.1155/2013/380985 fatcat:wxd4mev6pfhgbkyc72yklodzby

Improving communication for distributed model checking

Jean Fourie, Jaco Geldenhuys, Cornelia Inggs
2012 Proceedings of the South African Institute for Computer Scientists and Information Technologists Conference on - SAICSIT '12  
doi:10.1145/2389836.2389842 dblp:conf/saicsit/FourieGI12 fatcat:aiiogo5k4fguhizuamypyxgv74

Efavirenz exposure, alone and in combination with known drugs of abuse, engenders addictive-like bio-behavioural changes in rats

Marisa Möller, Jaco Fourie, Brian H. Harvey
2018 Scientific Reports  
Fourie assisted in the design of the study and along with M. Möller conducted the behavioural experiments, undertook the statistical analyses and prepared the first draft of the manuscript. B.H.  ... 
doi:10.1038/s41598-018-29978-3 pmid:30150782 fatcat:hubq4hos2rhaxmxm7sh2m6cwb4

Assessment of Mixed Sward Using Context Sensitive Convolutional Neural Networks

Christopher J. Bateman, Jaco Fourie, Jeffrey Hsiao, Kenji Irie, Angus Heslop, Anthony Hilditch, Michael Hagedorn, Bruce Jessep, Steve Gebbie, Kioumars Ghamkhar
2020 Frontiers in Plant Science  
., Fourie, J., Gebbie, S., et al. (2018). Using LIDAR for Forage Yield Measurement of Perennial Ryegrass (Lolium perenne L.) Field Plots. Breed.  ...  parsing network 6230–6239. doi: 10.1109/CVPR.2017.660 CrossRef Full Text | Google Scholar Keywords: forage yield, clover, ryegrass, biomass, semantic segmentation, deep learning Citation: Bateman CJ, Fourie  ... 
doi:10.3389/fpls.2020.00159 pmid:32174941 pmcid:PMC7056886 fatcat:od2ae44fkfdcjkn3j76dgctemu

Evaluating sources of variability in inflorescence number, flower number and the progression of flowering in Sauvignon blanc using a Bayesian modelling framework

Amber K. Parker, Jaco Fourie, Mike C. T. Trought, Kapila Phalawatta, Esther Meenken, Anne Eyharts, Elena Moltchanova
2022 OENO One  
The time of flowering is key to understanding the development of grapevines. Flowering coincides with inflorescence initiation and fruit set, important determinants of yield. This research aimed to determine between and within-vine variability in 4-cane-pruned Sauvignon blanc inflorescence number per shoot, number of flowers per inflorescence and flowering progression using an objective method of assessing flowering via image capture and statistical analysis using a Bayesian modelling
more » ... The inflorescence number and number of flowers per inflorescence were measured by taking images over the flowering period. Flowering progression was assessed by counting open and closed flowers for each image over two seasons. An ordinal multinomial generalised linear mixed-effects model (GLMM) was fitted for inflorescence number, a Poisson GLMM for flower counts and a binomial GLMM for flowering progression. All the models were fitted and interpreted within a Bayesian modelling framework. Shoots arising from cane node one had lower numbers of inflorescences compared to those at nodes 3, 5 and 7, which were similar. The number of flowers per inflorescence was greater for basal inflorescences on a shoot than apical ones. Flowering was earlier, by two weeks, and faster in 2017/18 when compared to 2018/19 reflecting seasonal temperature differences. The time and duration of flowering varied at each inflorescence position along the cane. While basal inflorescences flowered later and apical earlier at lower insertion points on the shoot, the variability in flowering at each position on the vine dominated the date and duration of flowering.This is the first study using a Bayesian modelling framework to assess variability inflorescence presence and flower number, as well as flowering progression via objective quantification of open and closed flower counts rather than the more subjective method of visual estimation in the field or via cuttings. Although flower number differed for apical and basal bunches, little difference in timing and progression of flowering by these categories was observed. The node insertion point along a shoot was more important. Overall, the results indicate individual inflorescence variation and season are the key factors driving flowering variability and are most likely to impact fruit set and yield.
doi:10.20870/oeno-one.2022.56.1.4717 fatcat:sb5gurfmsfed3kvidzjvntsyym

Knowledge and perceptions of antimicrobial stewardship concepts among final year pharmacy students in pharmacy schools across South Africa

Marisa Burger, Jaco Fourie, Devin Loots, Tercia Mnisi, Natalie Schellack, Selente Bezuidenhout, Johanna C. Meyer
2016 Southern African Journal of Infectious Diseases  
Antimicrobial stewardship is currently not mandatory as part of the undergraduate training of pharmacists. Identifying gaps in knowledge and a better understanding of pharmacy students' perceptions about antimicrobial stewardship could assist in recommendations for appropriate changes to the pharmacy degree curricula that may lead to more appropriate use of antimicrobials, within the multi-disciplinary team.Methods: A descriptive quantitative study with a survey design was conducted at the
more » ... universities offering the pharmacy degree in South Africa. An electronic questionnaire with four main categories on antimicrobial stewardship was administered to final (fourth) year pharmacy students (June–August 2015).Results: An overall response rate of 26.6% (n = 260) was obtained from 978 students, despite a weekly reminder. Most of the respondents were familiar with antimicrobial stewardship programmes in South Africa (71.9%), and claimed to know what antimicrobial stewardship is (83.5%) with significant differences between the universities (p 0.001). Only 37.7% of the respondents recalled having had formal training on antimicrobial stewardship, with responses from the eight universities differing significantly (p 0.001). However, almost all respondents (98.5%) felt that a strong knowledge of antimicrobials was important for their future career, with 90.0% indicating that they would like more training on antimicrobial stewardship at undergraduate level.Conclusion: There were significant differences between the eight universities with regards to undergraduate education on antimicrobial stewardship. In order to help prevent antimicrobial resistance, efforts should be made to introduce concepts of antimicrobial stewardship into the undergraduate pharmacy curricula to promote better use of antimicrobials and prevent antimicrobial resistance.
doi:10.4102/sajid.v31i3.83 fatcat:ds7z5vwb7ne4zamayk2rrsv5xa

Real-time, non-destructive and in-field foliage yield and growth rate measurement in perennial ryegrass (Lolium perenne L.)

Kioumars Ghamkhar, Kenji Irie, Michael Hagedorn, Jeffrey Hsiao, Jaco Fourie, Steve Gebbie, Valerio Hoyos-Villegas, Richard George, Alan Stewart, Courtney Inch, Armin Werner, Brent Barrett
2019 Plant Methods  
In-field measurement of yield and growth rate in pasture species is imprecise and costly, limiting scientific and commercial application. Our study proposed a LiDAR-based mobile platform for non-invasive vegetative biomass and growth rate estimation in perennial ryegrass (Lolium perenne L.). This included design and build of the platform, development of an algorithm for volumetric estimation, and field validation of the system. The LiDAR-based volumetric estimates were compared against fresh
more » ... ght and dry weight data across different ages of plants, seasons, stages of regrowth, sites, and row configurations. The project had three phases, the last one comprising four experiments. Phase 1: a LiDAR-based, field-ready prototype mobile platform for perennial ryegrassrecognition in single row plots was developed. Phase 2: real-time volumetric data capture, modelling and analysis software were developed and integrated and the resultant algorithm was validated in the field. Phase 3. LiDAR Volume data were collected via the LiDAR platform and field-validated in four experiments. Expt.1: single-row plots of cultivars and experimental diploid breeding populations were scanned in the southern hemisphere spring for biomass estimation. Significant (P < 0.001) correlations were observed between LiDAR Volume and both fresh and dry weight data from 360 individual plots (R2 = 0.89 and 0.86 respectively). Expt 2: recurrent scanning of single row plots over long time intervals of a few weeks was conducted, and growth was estimated over an 83 day period. Expt 3: recurrent scanning of single-row plots over nine short time intervals of 2 to 5 days was conducted, and growth rate was observed over a 26 day period. Expt 4: recurrent scanning of paired-row plots over an annual cycle of repeated growth and defoliation was conducted, showing an overall mean correlation of LiDAR Volume and fresh weight of R2 = 0.79 for 1008 observations made across seven different harvests between March and December 2018. Here we report development and validation of LiDAR-based volumetric estimation as an efficient and effective tool for measuring fresh weight, dry weight and growth rate in single and paired-row plots of perennial ryegrass for the first time, with a consistently high level of accuracy. This development offers precise, non-destructive and cost-effective estimation of these economic traits in the field for ryegrass and potentially other pasture grasses in the future, based on the platform and algorithm developed for ryegrass.
doi:10.1186/s13007-019-0456-2 pmid:31320920 pmcid:PMC6617592 fatcat:s4mqd2od6jckbhbovld3ivnfy4

The Application of Harmony Search in Computer Vision [article]

Jaco Fourie, University Of Canterbury
2011
The harmony search algorithm was developed in 2001 as a heuristic optimisation algorithm for use in diverse optimisation problems. After its introduction it was extensively used in multiple engineering disciplines with great success. In order to demonstrate the value of harmony search in computer vision applications I developed four novel algorithms based on harmony search that efficiently solves three problems that are commonly found in computer vision, namely visual tracking, visual
more » ... ence matching and binary image restoration. Computer vision is a large discipline that includes solving many different kinds of optimisation problems. Many of these optimisation problems are discontinuous with derivative information difficult or impossible to come by. The most common solution is to use population based statistical optimisation algorithms like the particle filter, genetic algorithms, PSO, etc. but harmony search has never been investigated as a possible alternative. This is surprising since harmony search has been shown to be superior to these methods in several other engineering disciplines. I therefore aim to show that harmony search deserves to be included in the computer vision researcher's toolbox of optimisation algorithms through the introduction of four novel algorithms based on harmony search that solve three diverse problems in computer vision. First the harmony filter (HF) is introduced as a visual tracking algorithm that is shown to be superior to the particle filter and the unscented Kalman filter (UKF) in both speed and accuracy for robust tracking in challenging situations. The directed correspondence search (DCS) algorithm is then introduced as a solution to the visual correspondence problem. Finally, two algorithms, counterpoint harmony search (CHS) and largest error first harmony search (LEFHS), are introduced for the blind deconvolution of binary images. Comparative results from these algorithms are very promising. The harmony filter was compared with the particle filter and the UKF both [...]
doi:10.26021/8447 fatcat:gqudkfgmwfhlxnh4gwc3goaomu

Review: "Miskruier", By Jaco Botha (2005)

Marthinus Beukes
2006 Tydskrif vir Letterkunde  
Jaco Botha. Kaapstad, Pretoria: Human & Rousseau. 2005. 228 pp. ISBN 0-7981-4581-1.  ...  Miskruier, Jaco Botha se eerste roman verskyn na twee kortverhaalbundels, In drie riviere (1997 ( ) en Sweisbril (2000 . Saam met Etienne van Heerden publiseer hy die Rooi rom@n in 1999.  ... 
doi:10.4314/tvl.v43i2.29764 fatcat:qymj72xqgrg5fcweqolmiku56e

Aanspreekliheid (Jaco Fouché)

Chantelle Gray
2021 Tydskrif vir Letterkunde  
Fourie, vertaal deur Marius Swart. Kaapstad: Kwêla, 2021. 256 pp. ISBN 978-0-7957-1001-8.  ...  It is clear: Jaco Diehl is a serial killer hiding in plain sight, a man unanswerable to anyone, yet giving an account of himself.  ... 
doi:10.17159/tl.v58i1.9117 fatcat:5ztvr7t5gnaodkmtji4xj3dz3e

Skryfvaardigheid en diepte verras sporadies in Skrywersblok en ander verhale

I. Jacobs
2012 Literator  
Jaco Fouché is al beskryf as 'n skrywer van voorstedelike literatuur. In al sy publikasies speel die voorstede, veral Bellville, 'n belangrike rol.  ...  Chris Fourie beklemtoon dat die mens se grootste vyand 'sleur en verveling en alledaagsheid en inskiklikheid is' (bl. 97). Die slot van 'Skrywersblok' stel egter teleur.  ... 
doi:10.4102/lit.v33i2.389 fatcat:yculfhm7wrdunlml6ntlmzwh7u

Resensie:"Repliek"

J Hambidge
2013 Tydskrif vir Letterkunde  
Sean O'Toole nie-het name opgelewer soos Willem Anker (Siegfried), Helena Gunter (Op 'n plaas in Afrika) en verder terug in die tyd: Spoor (Sonja Loots), Kom slag 'n bees (Izak de Vries) asook werke van Jaco  ...  Die impasse wat daar in die Afrikaanse digkuns geheers het, is opgehef met digters wat deur skryfskole of -programme beweeg het: René Bohnen, Aniel Botha, Fourie Botha, Karen Kühn, Martina Klopper, Loftus  ... 
doi:10.4314/tvl.v50i1.11 fatcat:l44webbj35horpoa23epghdoei

Page 166 of Biological Reviews Vol. 82, Issue 1 [page]

2007 Biological Reviews  
. & Jacos, T. 2004). Early brain growth in Homo erectus and implications for cognitive ability. Nature 431, 299-302. Crespl, E. J. & DENveER, R. J. (2005). developmental plasticity.  ...  Foury, R. A, & Lee, P.-C. encephalization in hominid evolution. Philosophical Transactions of Royal Society Serres B 334, 223-232. Fomon, S. J., THomas, L. N., Fiter, L. J. Jr., ZieGuer, E.  ... 
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