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Enhancing and Evaluating Software Test Case Diversity
Get PDFDiversity-based testing (DBT) has gained significant attention in software testing over the past two decades. DBT techniques use similarity metrics to exploit dissimilarity between software artefacts, such as requirements, inputs, or outputs, to address testing problems. This thesis advances the understanding and application of DBT to improve the diversity, effectiveness, and efficiency of software test suites. The research pursues three main objectives: (1) to analyse existing applications and artefacts used in DBT; (2) to develop automated approaches that apply DBT to test suite reduction and test case prioritisation; and (3) to explore new artefacts, such as bytecode, to enhance testing performance.
First, a systematic mapping study synthesised the landscape of DBT research, analysing 167 papers that employ 79 similarity metrics across 22 artefact types and 11 testing problems. The study identifies dominant trends, underexplored artefacts, and open challenges. Second, a string-based reduction technique was developed to minimise automatically generated test suites. This approach operates solely on test text, eliminating execution cost while maintaining fault detection capability. Third, the thesis investigates bytecode-level diversity as a novel artefact for test case prioritisation and mutant analysis. Results show that bytecode diversity improves fault detection by up to 7.8% and performs significantly faster than text-based approaches. Finally, the use of bytecode-based diversity in targeting stubborn mutants demonstrates superior efficiency, reducing test counts by up to 46% compared with coverage-based methods.
Overall, this thesis provides new insights into DBT theory and practice, introduces novel artefacts and techniques, and delivers scalable, effective solutions to key software testing challenges
The threat of mineral extraction to global vertebrate biodiversity
No full textMineral extraction is a rapidly expanding industry driven by continued demand for raw material for housing, infrastructure, technology and energy. The proximity of mines to regions of high biodiversity is increasing as easily accessible high-grade deposits are exhausted and the impacts of extraction are pushed out of sight and out of mind. Yet, these impacts can be highly variable, spatially vast and extend well beyond the closing of mining operations. In this thesis I use the IUCN Red List to investigate the threat of mineral extraction and mining processes to global vertebrate biodiversity, assessing the extent to which vertebrates are threatened, investigating the links between threatened species and extraction across commodity groups, and highlighting the biodiversity risk at individual mine sites and their primary extracted commodity. In Chapter 1, I find that mining threat to vertebrates is ubiquitous for all taxonomic groups, with threat to vertebrate biodiversity especially concentrated across tropical regions and within tropical moist broadleaf forest. In Chapter 2, I reveal that threat to vertebrate biodiversity is universal across commodity types, but that mines for each commodity are unevenly spatially distributed, resulting in coal, gold, and mines with unreported primary commodities being of particularly high conservation concern due to their risk and spatial extent. In Chapter 3, I highlight the need for better understanding of threats to biodiversity from non-metallic minerals and construction minerals through improved coverage of these mines and their production within global datasets and more detailed monitoring of their impacts on species. This thesis contributes the most comprehensive analysis of the biodiversity risks from mining, revealing considerable impact and risk of mineral extraction on global biodiversity. Societies need to adapt to prioritise innovative, equitable and circular economies to reduce raw mineral demands, transition away from fossil fuels and developing responsible mining practices where to mitigate against severe biodiversity losses
Local authorities and property developers’ relationships shaping spatial transformation: property development negotiations in Johannesburg and Cape Town since 2016
No full textThe Complex Relationship Between Central and Local Government in England: Progressing Agendas Under Structural Exclusion
No full textThe key interest of this thesis is to investigate the evolving and intricate relationship between central and local governments in the United Kingdom, with a specific focus on the impact and challenges of sub-regional governance and devolution in England. It critically examines how policies designed to decentralise power from central government to local regions have been implemented, highlighting issues such as the misalignment between urban and surrounding areas, and the uneven benefits of devolution. Furthermore, the thesis explores how regional policy actors attempt to advance local agendas within the constraints of centralised structures and dominant policy narratives, drawing attention to the concept of structural exclusion and the interplay between agency and structure in regional policy implementation. Ultimately, it seeks to provide timely insights into the ongoing debate around devolution in the UK
Exploring Human-Robot Futures through Participatory Design
No full textThe fields of robotics and assistive technology have historically been rarefied; removed from the needs and lived experiences of their potential end users, especially disabled people. Participatory Design (‘PD’), in which design is done with users as opposed to for them, is one way to redress this gap. This thesis explores the efficacy of using storytelling-based PD in robotic and assistive technology development through two studies.
Study 1 explores cultural imaginaries of robots and assistive technology with children with osteogenesis imperfecta (‘OI’, commonly known as brittle bone disease) and their families, blending Fictional Inquiry (Dindler & Iversen, 2007) with Science Fiction Prototyping (‘SFP’) (Johnson, 2011) in online and in-person workshops. The original contribution of this study is to evaluate a PD methodology for robotics as assistive technology with disabled potential end users that is grounded in popular culture, operationalising sociotechnical imaginaries as a common frame of reference for design activities.
Study 2 dives deeper into Johnson’s SFP (2011), conducting a critical review of its methodological structure and assumptions, using critical posthumanism as a theoretical lens to illuminate ways in which its utility as an emancipatory PD tool might be improved. The review informs a validation study of an interactive fiction platform that incorporates theory and praxis from video game storytelling to implement the suggested amendments. The original contribution of this study is to divorce SFP from its corporatist roots and so provide motivation for future work in employing (interactive) storytelling to pursue the emancipatory values of PD in technology design.
Together, Studies 1 and 2 provide evidence of the efficacy of storytelling-based PD in robotics and assistive technology development. The thesis contributes to the robotics and assistive technology fields through involving underrepresented perspectives (children with OI and their families) and its commitment to PD’s emancipatory values
Exploring the Impact of Automated Written Feedback on EFL Students Performance in Essay Writing.
Get PDFCurioversing wellness through the cyberstructure - A Classic Grounded Theory of Young People’s Experiences of Online Educational Spaces
Get PDFThis study explores how young people (YP) experience fully online educational spaces. Using Classic Grounded Theory (Classic GT) methodology, the research generated an emergent theory based directly on YP 's voices, without imposing adult assumptions. Six participants aged between eight and seventeen from a private, fee-paying online United Kingdom based school contributed through creative and conversational methods, including photovoice, diary writing, essays, and participant-led discussions.
The theory generated suggests that YP actively navigate their online education by a dynamic process called curioversing (the combining of curiosity and universe), which helps them build emotional and academic wellness. This process supports their cyberstructural wellness (a sense of balance and thriving within online environments).
YP’s experiences of online education are shaped by relationships with teachers, access to virtual tools, their own agency, and wider social inequalities, such as access to the internet (digital divide). These findings are drawn directly from the empirical data, which highlighted disparities in access and support across different home and school contexts. The study critiques dominant adult-centred models of online education that assume YP are passive recipients of technology. Instead, it presents a person-centred emergent theory that shows YP as meaning-makers who negotiate complex online spaces with creativity and resilience.
This research challenges neoliberal, one-size-fits-all models of online education. It calls for relational, flexible, and socially just approaches that centre YP’s lived realities. It also contributes to wider debates about online education, epistemic justice (fair recognition of YP's knowledge), and relational pedagogy. The study provides practical recommendations for policy and practice aimed at creating online educational environments that nurture connection, equity, and well-being
Evaluation of a panel of 105 cytokines from human glioblastoma (GBM) tissue maintained, and treated, on a unique microfluidic platform
Get PDFGBM remains a therapeutically challenging malignancy, partly due to its complex cytokine mediated microenvironment. This study established a novel microfluidic platform to maintain patient derived GBM tissue biopsies ex vivo for up to 12 days, enabling the dynamic profiling of cytokine responses under treatment (1μM GSK (Glycogen Synthase Kinase) 3368715 + 10μM Temozolomide). The combination of biochemical assays (LDH activity), histological analysis (H&E staining and Immunohistochemistry (IHC) for apoptotic markers), cytokine proteome profiling and ELISA assays provides evidence that GBM tissues can be maintained in a viable state within the novel microfluidic perfusion device for at least 12 days. Cytokine profiling was performed using Proteome Profiler array for 105 different cytokines, followed by ELISA validation for seven key cytokines (VEGF, MMP9, CHI3L1, IL6, IL8, Serpin E1, and Angiopoietin-2).
Multivariate analysis showed time significantly influenced cytokine profiles (p = 0.0288), with an overall downregulation over time. Treatment (temozolomide plus arginine methylation inhibitor) had no significant global effect on all cytokines expression level (p = 0.1977), but did significantly affect the seven selected cytokines (p = 0.0048). Univariate analysis confirmed VEGF (p = 0.0004) and MMP9 (p = 0.0046) were significantly downregulated with treatment, while CHI3L1 was upregulated (p = 0.0088). Additionally, gender (p = 0.0050) and age group (60 years; p = 0.0021) were both significant covariates influencing cytokine expression. However, these findings should be interpreted with caution given the small sample size (n=13), particularly the underrepresentation of female patients (3 females vs. 10 males) and the age imbalance (4 under 60 vs. 9 over 60).
Three of the study cytokines, VEGF, MMP9, and CHI3L1, were identified as responsive biomarkers under drug treatment, supporting further exploration of these targets. The platform provides a valuable tool for preclinical therapeutic screening and biomarker discovery. With further optimisation, it could support personalised treatment strategies and contribute to the development of more effective, patient-tailored approaches for managing GBM
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