Computing and Mathematical Sciences Papers

Permanent URI for this collectionhttps://researchcommons.waikato.ac.nz/handle/10289/6

This collection houses research from the School of Computing and Mathematical Sciences at the University of Waikato.

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10-year survival comparison of two cemented implants in primary total hip arthroplasty for osteoarthritis: A New Zealand regional study
(Springer, 2025) Pearce, Amy; Joshi, Chaitanya; Chan, Georgina; Lamberton, Tony; MacLean, Simon; Vane, Andrew; Hébert-Losier, Kim
Introduction Compare 10-year survival of the cemented highly crosslinked polyethylene Exeter® Rimfit™ (Rimfit) Cup and its predecessor, the ultra-high molecular weight polyethylene Exeter® Contemporary Flanged Cup™ (ECF), both with an Exeter® V40™ stem, in primary total hip arthroplasty (THA) for osteoarthritis in the Bay of Plenty region of NZ. Method We extracted national registry data for THA surgeries in the region between 1 January 2003 and 30 June 2023 and report the 10-year survival and reasons for revision of the two fully cemented implants (n = 495). We compared standard Kaplan-Meier estimates using the log-rank test. Cox proportional hazard models investigated the potential influence of six patient variables on the survival of each implant: sex, age, body mass index (BMI), ethnicity, American Society of Anesthesiologists (ASA) rating, and funding source (public/private). Results No statistically significant difference in 10-year survival rate between the implants (p = 0.334) (ECF 95.6% [93.4, 97.9], Rimfit 97.0% [95.9, 98.2]) or statistically significant difference in revision reasons between the implants (p = 0.09) was noted. Cox regression revealed no statistically significant influence of any of the six patient variables on the 10-year survival of the ECF (p = 0.584) or Rimfit (p = 0.611). Conclusion Both implants exceeded 95% survival at 10-years, which is favourable compared to the corresponding 94.8% national survivorship of cemented implants in NZ. There is no statistically significant difference in the 10-year survival rate or reasons for revision of the two cemented implants compared in this region. The Rimfit appears a suitable alternative to the ECF, from a survival and revision perspective.
15-year patient-reported outcomes of a cemented flanged cup and stem combination in primary total hip arthroplasty: A New Zealand study
(SAGE, 2026) Pearce, Amy; Joshi, Chaitanya; Chan, Georgina; Lamberton, Tony; MacLean, Simon; Vane, Andrew; Hébert-Losier, Kim
Methods: We investigated 15-year patient-reported outcomes (PROMs) and their predictors in primary total hip arthroplasty (THA) for osteoarthritis using a cemented flanged cup and stem from a regional joint registry in New Zealand. Regional data were collected for all primary THAs with this cemented combination from 1 January 2003 to 30 June 2023 who had recorded PROMs on at least 1 occasion (n = 263). PROMs included Oxford Hip Score, Western Ontario and McMaster Universities Arthritis Index and Veterans Rand-12, evaluated against patient age, ethnicity, sex, body mass index (BMI), funding pathway, and American Society of Anesthesiologists (ASA) rating. Results: Significant improvements across preoperative PROMs were noted 1-year post-surgery, with a mean change above 23 in the Oxford Hip Score maintained at 5, 10, and 15 years (p ⩽ 0.001). Conclusions: Regression analysis indicated that being female, public funding, and higher BMI were associated with worse preoperative PROMs. Poorer preoperative scores, older age and ASA 3 rating correlated with poorer postoperative outcomes.
Computer graphic art of clothing
(2019) Soo, Chin-En Keith
We are living in an ever-changing world, where new methods are being introduced to carry out the most staightforward task, where new inventions are being proposed to ease our daily operations, where new ideas are popping out at every corner. Since the dawn of time, mankind has been using innovation and creativity to survive and enhance life. With the use of technology, it has enabled more possibility and more significant endeavour. Now and forever, we are dependant on technology, that has played a substantial role in our design solutions, which inescapably affect every one of us.
Type brighter
(Domus Argenia, 2013) Soo, Chin-En Keith; Soddu, C; Colabella, E
Type Brighter is intended as a new way of reading the alphabet. Shape, colour and pattern create memorable sequences based on characteristics of the letterform. By utilizing colour and repetition, readability is promoted. Each letter of the English alphabet is assigned a colour and positions, resulting in a full set of unique patterns. The user types using the keyboard, and the corresponding lights are shown on the light board. The simplicity of colour makes Type Brighter an alternative to more complicated communications such as mores code, and the use of pattern creates memorable sequences of colour. User can also experience the change of ambience, while the moving colour type projects an abstract story using light. Type Brighter aims to create a new visual language through light. Colour, shape and pattern are strong visual elements, and when combined create a memorable experience. Colour serves an important part of our everyday lives and is easily distinguishable in all situations, making Type Brighter effective in a range of applications.
RenderRing
(Domus Argenia, 2015) Soo, Chin-En Keith; Soddu, Celestino; Colabella, Enrica
Renderring is a musical platform for intuitive composition. It enables users’ interaction to provide opportunity for anyone to draw a unique circle and translates the drawing into a piece of melody. Users are able to set the composition variables before they start (Tempo, time signature and number of notes). The process involves two parts: First is a collection of user input by getting user to draw any unique circle in a provided space. Second is an interpretation using the program to decipher the drawing and identify point of intersections on the musical staff. After which, the program will produce a unique piece of melody with the user’s drawing. The user can then proceed with options of redoing or saving the melody. Renderring aims to bring new experience to create melody with a vision to simplify complexity. Transferring oneself energy from one form to another by converting visual to sound. The process enables creativity and empowers everyone to express his or her hidden inner potentials by making straightforward music.
Hueue
(Domus Argenia, 2017) Soo, Chin-En Keith; Soddu, Celestino; Colabella, Enrica
HUEUE aims to capture the colour story of a movie and present it in an accessible time frame of a minute. Movies at their simplest are colour, sound and motion. HUEUE aims to distil any movie into these basic forms and generate a unique form of escapism, bring the audience on a journey into the movie itself. HUEUE creates a tunnel effect. The effect indicates an impression of a portal. This is intended to give life to the escapism and create a more concrete feeling of the journey with the aid of sequential colours flowing from the movie. The audio is condensed creating a pitch shift, simulating the Doppler effect. All these elements create an experience that accelerate the viewer into the escapism and further into the movie.
Palate 字觉
(Domus Argenia, 2018) Soo, Chin-En Keith; Soddu, Celestino; Colabella, Enrica
Chinese characters are a visual symbol with strong contagion. Palate uses the pronunciation and character structure of Chinese characters as the entry point to colorize the Chinese characters so as to give them the possibility of expressing colors in the design of Chinese characters. Each Chinese character has its own unique color system. The application of the colorisation of Chinese characters can help to study the artistic charm of Chinese characters from a new perspective, improve the visual impact of Chinese characters, break the limitations of the past in the search for changes in the design of Chinese characters, and seeking a new form of modern Chinese character design.
ebBe
(Domus Argenia, 2021) Soo, Chin-En Keith; Simmons, Rowan; Soddu, Celestino; Colabella, Enrica
ebBe is a visualisation of tweets in realtime. ebBe uses word frequency to express the notion and motion of an ebb by contracting lines representing creation and decay. The created lines in different qualities will mimic and manifest a live visual artwork.
Chromatic ghost
(Domus Argenia, 2024) Soo, Chin-En Keith; Simmons, Rowan; Soddu, Celestino; Colabella, Enrica
"Chromatic Ghost" delves into the convergence of artificial intelligence and the emotional narrative of cinema, exploring how palettes can AI-generated colour visually express the emotional depth of films. The project aims to assess the capabilities of AI in understanding and translating human emotions into visual representations, questioning how effectively machines, which are increasingly embedded in our "Chromatic Ghost" is a creative experiment designed to investigate how AI can interpret and visualise human emotion in the context of film. In an era where artificial intelligence is increasingly intertwined with our daily lives, this work examines how well these technologies can grasp and reflect the complexities of human emotions, which are often considered too nuanced or abstract for machines to comprehend. lives, can interpret the intricacies of our emotional experiences. By using AI to generate emotion- based colour palettes and applying them to film frames, "Chromatic Ghost" transforms iconic cinematic scenes into layered, ethereal images that evoke the emotional core of the films in a spectral, dreamlike manner. The resulting visual compositions—ghostly, fragmented, and nuanced—invite viewers to contemplate both films' emotional resonance and AI’s role as a mediator of this experience.
Co-WARe
(Domus Argenia, 2022) Soo, Chin-En Keith; Soddu, Celestino; Colabella, Enrica
Throughout history, humans have been creating receptacles in their daily activities to hold, keep, and preserve the rewards and objects they treasure. Applying the same notion, Co-WARe makes unique receptacles from covid data to express the information in an artistic form. Co-WARe is an objectified presentation of all COVID-19 cases, deaths, geographically located data in each country, and the time of the data was generated. These data series project the different changes brought to each country since the beginning of COVID-19. It also provides more intuitive insight into the epidemic in all countries worldwide.
A natural behavior planner for multi-personal human-robot interaction within the simulated environment
(Elsevier BV, 2026-03) Chen, Yue; Zheng, Pai; Zhou, Zhiyuan; Soo, Chin-En Keith; Wang, Haining; Yu, Chunyang
In recent years, diffusion models have made remarkable success in generating realistic human motions. However, existing robot pose-learning approaches are largely focused on single-task and one-to-one scenarios, failing to account for multi-person social interactions. This limitation leads to rigid, context-insensitive behaviors that are ill-suited for real-world service scenarios. Consequently, current systems often produce robotic behaviors incapable of the fluidity and responsiveness expected in human-centered environments, a shortcoming underscored by affordance theory in robotics. To address this issue, we propose RoboActor, an innovative human-robot interaction behavior planner that draws inspiration from theatrical acting to orchestrate both deliberate and automatic actions. Our framework leverages large language models (LLMs) to disentangle primary command-driven tasks from secondary, context-induced subtasks. By this means, RoboActor generates lifelike and socially appropriate behaviors in multi-person settings, significantly enhancing the naturalness, engagement, and realism of service robots in everyday social applications.
Parasthetica: Artworks for GA2025
(Domus Argenia Publisher, 2025-12) Soo, Chin-En Keith; Simmons, Rowan; Soddu, Celestino; Colabella, Enrica
Parasthetica transforms eBooks into abstract visual artworks through a character-matching system that maps literary text into chromatic geometric forms. The program positions itself at the crossroads of digital humanities, generative art, and data visualisation. Each text becomes a living artwork, where words are translated into dynamic, colour-based grids that reveal hidden linguistic and structural patterns. Rather than statistical summaries, the visualisations offer immersive aesthetic experiences that mirror the rhythm, genre, and emotional intensity of the source material.
Augmenting NIR spectra in deep regression to improve calibration
(Elsevier, 2023) Wohlers, Mark W.; McGlone, Andrew; Frank, Eibe; Holmes, Geoffrey
Deep learning, particularly with convolutional neural networks, shows promise in modelling near-infrared spectroscopy (NIRS), but the lack of robust generalisation across instruments often affects performance in practice. Here, we investigate a method to increase the robustness of this approach. The proposed method involves using a simple data augmentation technique during the training process. The performance of convolutional neural network regression is compared to partial least squares regression (PLSR) using kiwifruit data collected from multiple handheld devices over three seasons and mango data collected from a single device over four seasons. The results suggest that data augmentation for NIR spectra can prevent overfitting. In particular, augmenting the training data to mimic spectra collected over multiple devices results in a neural network model with improved performance over PLSR.
Barlow Twins for semi-supervised learning in NIR spectroscopy
(Elsevier BV, 2026-02-15) Wohlers, Mark W. ; McGlone, Andrew; Frank, Eibe; Holmes, Geoffrey
Near-infrared (NIR) spectroscopy is a widely used technology in the horticulture industry for non-destructive fruit grading. Partial Least Squares (PLS) regression is the dominant method for producing fruit quality predictions from measured spectra. Alternative deep learning methods have shown promise, but often require large amounts of labelled data to train. This study proposes a semi-supervised method based on Barlow Twins to include unlabelled data in the training process. We adopt the Barlow Twins method by using repeated measurements on the same fruit from different devices as different “views” to encode into the same latent space and combine the encoder network with a regression head for prediction. Our approach demonstrates improved performance over PLS with up to 17% lower RMSE, especially when the labelled data is limited. The Barlow loss function also improves calibration transfer results.
Assessing machine learning models for near-infrared regression by measuring stability towards diffeomorphisms
(Elsevier, 2025) Wohlers, Mark W.; McGlone, V.A.; Frank, Eibe; Holmes, Geoffrey
Near infrared (NIR) spectroscopy is widely used as a tool for non-destructive assessment of fruit quality by applying measured spectra to predict quality parameters such as dry matter and soluble solids content using a suitable regression method. With continued advancements in deep learning, there is potential for improved predictive performance when neural network models are applied instead of partial least-squares regression, but choosing a model remains challenging as performance is sensitive to the model's architecture. Taking inspiration from work done in image classification, we propose model selection by assessing relative stability to diffeomorphic transformations, providing a complementary approach to standard validation methods. This is particularly useful when labelled validation data is limited. Our empirical results on several NIR regression problems indicate that the proposed approach is comparable to the use of independent validation sets. In addition to the choice of deep learning architecture, we also consider the selection of the number of components in partial least-squares regression to demonstrate the method's generality.
Investigating the data in investor alerting portals
(Springer Science and Business Media LLC, 2025-12-09) Nichols, David M.; Chew, Chris; Kumar, Vimal
Financial regulators in many jurisdictions publish investor alerts that identify newly identified threats such as imposter websites and unlicensed firms. Many of these lists are aggregated by the International Organization of Securities Commissions. We analyse these alerts to understand if they can be used to create cybersecurity measures to protect consumers. An exploratory study indicates that the dangerous websites identified in the alerts are largely not detected by the safety services in web browsers. The financial security of consumers can be improved through coordination between the financial regulators, browser developers and cybersecurity services. We provide recommendations for improving the effectiveness of investor alerts through better data publication practices.
Teaching sustainability in design: assessing the usability of the design for amelioration tool
(Emerald, 2025) Lubis, Pierre Yohanes; Ramirez, Mariano; Shahri, Bahareh
Purpose This study aims to evaluate the usability and effectiveness of the Design for Amelioration (DfA) tool in an educational setting, examining its reception among industrial design students, its impact on the design process and areas for potential improvement. Design/methodology/approach A cohort of second- and third-year industrial design students applied the DfA tool in their studio projects over a 12-week period, using its structured framework to guide their decision-making. By incorporating people, planet and profit, the tool encouraged students to balance social responsibility, environmental impact and economic viability in their designs. After project completion, focus group discussions were conducted to gather insights into students’ experiences. Findings The findings indicate that the DfA tool was well-received, with students finding it accessible and beneficial in structuring their design process around sustainability. They appreciated its ability to promote holistic thinking across the three sustainability pillars, though they suggested refinements such as greater flexibility between stages and optional weightings for each pillar. Originality/value This study underscores the importance of structured sustainability tools in design education and provides insights into how tools like the DfA can be refined to enhance pedagogical impact. The findings contribute to sustainable design education discourse and highlight the role of usability-focused tools in shaping future design practices.
Fostering community empowerment: A human-centered approach to designing clean water solutions in a Jakarta slum
(SAGE, 2024) Lubis, Pierre Yohanes; Shahri, Bahareh; Ramirez, Mariano
This article presents a case study of the application of human-centered design (HCD) as a codesign approach to address complex problems in slum communities in Jakarta, Indonesia. Through a review of relevant literature, we examine how the HCD methodology embraces a participatory framework but retains a certain degree of control not found in pure participatory approaches. We explain why HCD was selected for this study and describe the methods used, including sort cards, solution cards, in-depth interviews, focus group discussions, and product usability interviews. These methods were employed to generate a solution that addressed the issue of sourcing clean water in Jakarta’s slums, which was then prototyped, tested, and implemented. The study contributes to the development of a cohesive and applicable methodology by integrating codesign and HCD in designing solutions for people at the Base of the Pyramid.
Exploring student perceptions of product-service systems
(Routledge, 2025) Lubis, Pierre Yohanes; Shahri, Bahareh
It is important that Product Design students understand the scope of sustainable design. The purpose of this study is to pilot the introduction of Product-Service System (PSS) Design to undergraduate students in Industrial Product Design. The study aims to test students' perceptions of how the Product Design field is evolving to embrace sustainable approaches address the needs of less-privileged communities. This chapter highlights how the transformation from product design to PSS Design is understood by students and how it can count towards sustainability and be preferred over product design. The advantages of a PSS over the design of products alone can be backed by the concept of sustainability when contextual issues such as cultural and economic factors are being considered. PSS was received to be an appropriate solution by providing job creation in communities, reducing consumerism, and, at the same time, being perceived to challenge the concept of ownership of products and services.
Re-evaluating fatigue measurement: A comparative study of subjective and objective fatigue tests
(Elsevier BV, 2025) König, Jemma Lynette; Bowen, Judy; Hinze, Annika
Fatigue poses a significant risk in hazardous industries, with forestry being a particularly under-examined domain. Despite the availability of subjective and objective fatigue tests, inconsistencies in their application, selection rationale, and performance remain largely unaddressed in existing literature. This paper investigates the utility and challenges of subjective and objective fatigue assessments through a review of existing literature and two case studies: one intensive longitudinal study with a single participant and another broader study involving 31 participants. Our results reveal strong internal consistency across subjective tests but variable outcomes for objective tests, raising questions about test sensitivity and context-specific reliability. We argue for clearer guidance on fatigue test selection and propose criteria to inform future research in complex, real-world settings like forestry.

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