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Integration of stereo vision system calibration and kinematic calibration for an autonomous kiwifruit harvesting system
(Springer Nature, 2022) Au, Chi Kit; Lim, Shen Hin; Duke, Mike; Kuang, Ye Chow; Redstall, Michael; Ting, Canaan
Stereo vision system and manipulator are two major components of an autonomous fruit harvesting system. In order to raise the fruit-harvesting rate, stereo vision system calibration and kinematic calibration are two significant processes to improve the positional accuracy of the system. This article reviews the mathematics of these two calibration processes and presents an integrated approach for acquiring calibration data and calibrating both components of an autonomous kiwifruit harvesting system. The calibrated harvesting system yields good positional accuracy in the laboratory tests, especially in harvesting individual kiwifruit. However, the performance is not in line with the outcomes in the orchard field tests due to the cluster growing style of kiwifruit. In the orchard test, the calibrations reduce the fruit drop rate but it does not impressively raise the fruit harvesting rate. Most of the fruit in the clusters remain in the canopy due to the invisibility of the stereo vision system. After analyzing the existing stereo vision system, a future visual sensing system research direction for an autonomous fruit harvesting system is justified.
A multidimensional activity theory framework for human computer interaction with Digital Twins
(University of Waikato, Department of Software Engineering, 2025) Adeel, Aleeza; Apperley, Mark
This paper introduces a human-centred framework to address the interaction and usability challenges of complex Digital Twin (DT) systems by proposing a new generation of Activity Theory, named Pyramidal Activity Theory (PAT). Digital twins are virtual representations of physical processes, systems, or components that are continuously synchronised with real-world data. Despite their growing adoption across industries, their graphical representation remains challenging due to the diversity of application domains, where multiple models—spanning different users, phases, and scales—are typically distributed across heterogeneous software packages. These complexities often result in inconsistencies, fragmented workflows, and communication barriers across domains. The proposed model builds upon the previous generation of activity theory, extending it into a 3D pyramidal structure while excluding motivational factors to focus exclusively on interaction mechanics. PAT provides a coherent model for designing unified, user-centred interfaces by capturing dynamic interactions among the key elements of DT systems—Users, Tools (Models), Live Data, Interfaces, and Outcomes—and their interrelationships. Two case studies are presented to demonstrate its applicability. Case Study 1 maps human–system interactions in advanced manufacturing, clarifying roles and activity flows to make the framework understandable and directly applicable for practitioners. Case Study 2 validates PAT through an implemented prototype for industrial energy optimisation. The proposed model introduces a novel 3D interaction paradigm, providing a scalable and adaptable framework for digital twin interface design. It improves usability, standardisation, and decision-making by clarifying stakeholder roles, reducing cognitive load through “black-box” model integration, and ensuring consistent logic from regional planning to unit-level control. The paper concludes with future research directions, including usability testing, interface refinement, and alignment with interoperability and accessibility standards.
Personal therapy in psychology training: Perspectives from the practising field
(The University of Waikato, 2025) Mills, Briar; Mohi, Simone R.
The potential relevance of personal therapy for psychologists in training has long been discussed, yet few empirical studies have explored how it is perceived by psychologists themselves. This study investigated the views of 219 Australian psychologists who had engaged in personal therapy, drawing on their written qualitative responses to a larger online survey distributed across Australia. Thematic analysis was used to explore participants’ perspectives on personal therapy during training. Seven key themes were identified, reflecting diverse views on whether therapy should be required, the challenges and barriers that can affect access, and how stigma or normalisation influence uptake. Participants described how personal therapy during training was viewed as contributing to professional and personal development, enhancing self-awareness, emotional insight, and relational capacities, as well as offering support that extended beyond the limits of supervision. Some also highlighted the protective and sustaining role of therapy and its alignment with professional values. Views on whether therapy should be mandated varied, but many supported increased encouragement and visibility within training contexts. These findings offer timely insight into how psychologists with lived experience of personal therapy reflect on its role during training, highlighting considerations for professional development, trainee wellbeing, and the broader training environment.
Comparing the psychological well-being of working and non-working mothers
(The University of Waikato, 2025) Mir, Ayesha; Milfont, Taciano L.
The well-being of parents is essential for the health and development of both their families and themselves. Both parents contribute greatly to their children’s development and growth. In contrast to fathers, however, mothers have higher responsibilities in handling household chores and children, along with their professional obligations. Indeed, the employment status of mothers is a crucial determinant of their life satisfaction and happiness. Due to a lack of comprehensive cross-cultural studies that examine the psychological well-being among working and non-working mothers, the present pre-registered study was designed to explore the difference in psychological well-being measured as happiness and life satisfaction among working and non-working mothers in New Zealand and Pakistan. The study utilized the data from the World Value Survey Wave 7 and employed a quantitative cross-sectional research design to investigate the psychological well-being of 252 working and 206 non-working New Zealand mothers, and 78 working and 78 non-working Pakistani mothers. The findings demonstrated that non-working mothers in New Zealand experienced higher life satisfaction compared to working mothers, whereas in Pakistan, working mothers reported greater life satisfaction than non-working mothers. The result emphasizes the influence of culture, employment status, and social support systems in shaping the well-being of mothers. Recommendations are made for culturally relevant interventions that tackle the challenges faced by mothers in developing and developed countries. Future research can explore socioeconomic status, and ethnicities as additional factors that might influence the well-being of mothers.
Towards identification of floc compounds in water using multi-frequency fluorescence lifetime analysis
(The University of Waikato, 2025) Dissanayake, S.A.D. Asanka Nilakshi; Cree, Michael J.; Lay, Mark C.; Streeter, Lee; Glasgow, Graeme D.E.
UV disinfection is commonly used in water treatment to inactivate pathogens such as Cryptosporidium and viruses to prevent diseases such as cryptosporidiosis and norovirus in communities. Disinfection typically follows water treatment steps, such as coagulation, flocculation, clarification, and filtration. However, particles in water, for example, flocs 0.1 to 100 μm in diameter, made from humic and inorganic substances present in the water, surrounding a Cryptosporidium oocyst or virus, can protect the pathogens from UV exposure. Although water treatment steps prior to disinfection remove 99% of the particulates, particles can still be present in the 1000s to 10,000’s per litre after filtration. While the chances of a floc particle carrying a virus or oocyst are typically low, in some regions, particularly during calving in the dairy industry, oocyst concentrations in the water might be high due to cryptosporidiosis in calves. Therefore, it is useful to test the properties of the floc compound for UV penetration to determine whether the disinfection method is appropriate. In this thesis, a technique that uses multi-frequency analysis to measure the fluorescence lifetime of a fluorophore to provide information on particle composition is presented. Frequency-domain fluorescence fluorometry was used to determine the fluorescence lifetime. This was achieved using an experimental setup that used a laser diode operating at 100 mW and modulated at 10–60 MHz to excite the fluorophores, optical elements to focus and filter the light, and detectors to collect the fluorescence emission signal via a storage oscilloscope. The signals were then processed using a MATLAB program to determine the fluorescence lifetime. Fluorescence lifetime measurements were challenged by the chemical and physical behaviour of the fluorophore and the adsorption of the fluorophore to the floc particles. Therefore, standard measurements such as turbidity, pH, particle size, and fluorescence were used to understand the absorption/adsorption of fluorescein to flocs. Fluorescence was observed at the 260–490 nm excitation wavelengths, with fluorescence emissions at approximately 510 nm. The particle size and turbidity measurements showed that fluorescein acted as a flocculant, with the particle size increasing with increasing fluorescein concentration. Fluorescence intensity measurements from a standard fluorescence spectrophotometer were used to calculate fluorescein adsorption on humic acid and kaolin to generate adsorption isotherms. Fluorescein was bonded to kaolin 10 times more than to humic acid. Adequate flocculation required a pH of 6.5 to produce reasonably flocculated particles in the sample. Surface charge analysis showed that the use of buffer to control pH required more alum to neutralise the surface charge of humic acid and kaolin. Multi frequency measurements and subsequent analysis showed that the fluorescence lifetime and contamination ratio were 4.2 ± 0.3 ns and 0.09 ± 0.05 for fluorescein. The fluorescence lifetime of fluorescein was compatible with the results of previous studies using different techniques. The samples with floc particles had a larger excitation light contamination ratio than those without particles; therefore, the contamination ratio could be used as a measure of particle contamination in the samples. The fluorescence lifetime of fluorescein did not change when fluorescein was attached to humic acid particles, but increased by 0.6 ns for kaolin floc particles.