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Investigating the impact of compression ratio on hydrogen combustion and emission: An experimental analysis
Get PDFRecent development of hydrogen (H₂) internal combustion engine (ICE) technologies has demonstrated that they produce zero CO₂ and ultra-low NOₓ emissions without aftertreatment. Therefore, H₂ ICE is well suited as a sustainable zero-carbon thermal power unit towards the net-zero target in the future. Increasing the compression ratio (CR) in IC engines can improve the indicated thermal efficiency (ITE). However, in spark ignition (SI) engines using gasoline, the CR is typically limited to around 10:1 due to knocking combustion. Hydrogen, with its higher autoignition temperature and octane number, can be used with a higher CR. This study aims to experimentally assess hydrogen as a direct replacement for gasoline in highly boosted single-cylinder SI engines with different CRs by swapping engine pistons. Two sets of experimental testing have been conducted at various engine speeds. Starting from a lambda (λ) sweep test involved leaning out the combustion to reach the engine stability-operating limits. The second test involved conducting a load sweep test on every CR at various loads to get the engine’s maximum in-cylinder pressure limits. The results indicate that, under the synergistic restriction of the engine strength and the lean-burn limitation, there is a crucial trade-off between peak and maximum engine power with various CR. Specifically, a higher compression ratio (i.e. CR = 12.39) resulted in a 5% increase in ITE compared to CR = 9.27. However, the lower compression ratio increased the maximum engine torque by 3.50 bar of indicated mean effective Pressure (IMEP). In addition, although hydrogen can remain stable combustion across a broad range of lambda and operating loads, the NOₓ emissions increased with CR, due to the higher combustion temperature. These findings provide valuable insight into hydrogen engine applications and improve the understanding of SI hydrogen engine’s performance and development.The author(s) received no financial support for the research, authorship, and/or publication of this article
Reversed Model Verification by Inferring Conceptual Models from Simulation Code
No full textExtracting high-level conceptual models from simulation code can benefit model validation and verification, system optimisation, and cross-disciplinary communication. However, conceptual models are often embedded within implementation details, making them difficult to access and interpret. This paper explores the feasibility of using Large Language Models (LLMs) to infer conceptual models from simulation code. We conduct a preliminary investigation on an agent-based simulation (Flee), demonstrating how LLMs can extract key structural, behavioural, and temporal elements. Our results suggest that LLMs can generate meaningful conceptual representations that align with expert-created models, offering potential support for model verification. However, we also identify limitations such as omissions and misinterpretations, highlighting the need for human oversight. While our study is based on a single example, it provides initial insights into the role of LLMs in conceptual model inference and their potential integration into simulation validation workflows.This work has been supported by the SEAVEA ExCALIBUR project, which has received funding from EPSRC under grant agreement EP/W00771/1
Processability improvement and strength enhancement in laser powder bed fusion of AlMgZr and AlMgZr-Ti alloys
Get PDFData availability statement:
Data are available from the corresponding author on reasonable request.The Al3(Ti, Zr) phase, which exhibits a lower formation enthalpy, was incorporated to improve the processability and strength of AlMgZr alloys fabricated by laser powder bed fusion (PBF-LB). The results confirmed that the crack-free AlMgZr-Ti alloy exhibited a relative density of 99.7% and a fine grain size of ∼ 2.5 μm. The improved processability can be attributed to grain refinement and the columnar-to-equiaxed transition (CET), which is induced from promoted heterogeneous nucleation by in-situ Al3(Ti, Zr) phase and high grain growth restriction factor by segregation of Ti at the interface. During solidification, Al3Ti phase was precipitated initially and Zr was incorporated into the Al3Ti lattice in the subsequent precipitation, accelerating Zr precipitation from α-Al matrix. Through experimental results and calculations of formation enthalpy in combination, the Al3(Ti, Zr) phase was most likely to be Al3(Ti5/6, Zr1/6). Meanwhile, the AlMgZr-Ti alloy exhibited superior strength in comparison with the counterpart of AlMgZr alloy, where the enhancement of YS (408 MPa) and UTS (432 MPa) is 119% and 42.6%, respectively, with the UTS of the AlMgZr-Ti alloy maintaining 182 MPa at 300 °C.This work was supported by the National Natural Science Foundation of China under [grant number 52071343] and the Central South University Postgraduate Research and Innovation Project, China under [Grant 2024ZZTS0079]
Designing a sustainable hydrogen supply chain network in the Gulf Cooperation Council (GCC) region: Multi-objective optimisation using a Kuwait case-study
Get PDFHighlights:
• A solar-powered green hydrogen supply chain is designed for Kuwait in 2050.
• Cost, carbon footprint, and safety are optimised for a hydrogen supply chain.
• A hydrogen gas supply chain is generally more favourable than liquid.
• Higher demand amplifies efficiency gains and operational savings.
• Pipelines and salt caverns emerge as optimal transport and storage choices.Supplementary data are available online at: https://www.sciencedirect.com/science/article/pii/S0360319925014314?via%3Dihub#appsec1 .Located in the Arabian Gulf, Kuwait is a renewable-abundant country ideal for producing hydrogen via solar energy (green hydrogen). With a global transition away from fossil fuels underway due to their adverse environmental impacts, hydrogen is gaining significant traction as a promising clean energy alternative for the transport sector. Despite this, there are still various challenges associated with implementing a hydrogen supply chain, particularly with regard to the conflicting objectives of minimising cost, environmental impact and risk. This study determines the feasibility of implementing a green hydrogen supply chain in Kuwait based on a multi-objective design, to determine which combination of production (electrolysis type), storage method and transportation method is the most optimal for Kuwait. Three objective functions were considered in this study: the hydrogen supply chain cost, environmental impact, and safety/risk. A mathematical formulation based on mixed integer linear programming (MILP) was used, involving a multi-criteria approach where the three considered objectives must be optimised simultaneously, i.e., cost, global warming potential and safety/risk. The multi-objective optimisation approach via the weighted sum method was applied in this study and solved via GAMS. To account for the ranking of multi-objective criteria, a hybrid AHP-TOPSIS approach was used. Results showed that medium and high demand scenarios better reflect the comparative advantages of each considered method in terms of their multi-objective trade-offs. In particular, it was found that higher hydrogen demand amplifies the impact of higher efficiency and operational savings within several production, storage and transportation methods, and that despite higher initial capital investments, these costs are at some point offset by superior operational efficiency as hydrogen production volumes increase. Conversely, using highly efficient electrolysers or transportation methods at low demand was found to limit their performance.Ministry of Education, Science and Sports of the Republic of Lithuania and Research Council of Lithuania (LMTLT) under the Program ‘University Excellence Initiative’ Project ‘Development of the Bioeconomy Research Center of Excellence’ (BioTEC), agreement No S-A-UEI-23-14
From smoking cessation to physical activity: Can ontology-based methods for automated evidence synthesis generalise across behaviour change domains? [version 2; peer review: 2 approved, 1 approved with reservations]
Get PDFData availability:
Underlying data
Open Science Framework: Human Behaviour-Change Project. https://doi.org/10.17605/OSF.IO/EFP4X (West et al., 2023b)
Extended data
Online supplementary materials cited in this article are available below:
Supplementary material 1: Questionnaire for physical activity experts (https://osf.io/9vwye/).
Supplementary material 2: HBCP physical activity annotation manual (https://osf.io/8ekfz).
Supplementary material 3: Comparison between HBCP physical activity and smoking cessation annotation code sets (https://osf.io/n3e9y).
Supplementary material 4: Responses to physical activity experts feedback (https://osf.io/n56kj/).
Supplementary material 5: Intervention reports included in HBCP physical activity corpus (https://osf.io/kdmwe).
Supplementary material 6: Annotations for 111 intervention reports included in HBCP physical activity corpus (https://osf.io/dtn6u).
Data are available under the terms of the Creative Commons Attribution 4.0 International license (CC-BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original data is properly cited.Amendments from Version 1:
In this updated version, we have made the following revisions to address reviewer feedback:
- Expanded the introduction to better contextualise the Human Behaviour Change Project (HBCP) approach within the broader research landscape.
- Clarified the keywords used in the literature search and specified the level in which these keywords were searched (i.e., title/abstract).
- Provided a rationale for using proprietary software to conduct the research (EPPI-Reviewer and Qualtrics).
- Included both (i) lack of pre-registration and (ii) the geographical concentration of physical activity experts consulted as study limitations and outlined plans for global engagement via the APRICOT project.
- Provided a stronger rationale for the inclusion of sedentary behaviour as part of the list of physical activity behavioural outcomes.
- Elaborated on the potential limitations of an AI-based evidence synthesis approach, as a result of the underlying evidence’s quality and bias.
- Revised the title to better reflect the study’s focus on evaluating ontology-based evidence synthesis across behaviour change domains.
- Amended the abstract and introduction to strengthen the study rationale, unpack the term evidence synthesis, and explain the need for an approach such as the HBCP’s.
- Added further details regarding the survey for physical activity experts during stage 1, covering analysis and deployment.
- Clarified that the annotations during stage 4 resulted in iterative updates to the annotation manual as well as changes to the physical activity annotation code set.
- Revised the discussion to emphasise the study’s knowledge gap and to include a wider range of literature outside the HBCP.This article is included in Human Behaviour-Change Project (including the APRICOT project) gateway (https://wellcomeopenresearch.org/gateways/humanbehaviourchange/about).Background:
Developing behaviour change interventions able to tackle major challenges such as non-communicable diseases or climate change requires effective and efficient use of scientific evidence. The Human Behaviour-Change Project (HBCP) aims to improve evidence synthesis in behavioural science by compiling intervention reports and annotating them with an ontology to train information extraction and prediction algorithms. The HBCP used smoking cessation as the first ‘proof of concept’ domain but intends to extend its methodology to other behaviours. The aims of this paper are to (i) assess the extent to which methods developed for annotating smoking cessation intervention reports were generalisable to a corpus of physical activity evidence, and (ii) describe the steps involved in developing this second HBCP corpus.
Methods:
The development of the physical activity corpus involved: (i) reviewing the suitability of smoking cessation codes already used in the HBCP, (ii) defining the selection criteria and scope, (iii) identifying and screening records for inclusion, and (iv) annotating intervention reports using a code set of 200+ entities from the Behaviour Change Intervention Ontology.
Results:
Stage 1 highlighted the need to modify the smoking cessation behavioural outcome codes for application to physical activity. One hundred physical activity intervention reports were reviewed, and 11 physical activity experts were consulted to inform the adapted code set. Stage 2 involved narrowing down the scope of the corpus to interventions targeting moderate-to-vigorous physical activity. In stage 3, 111 physical activity intervention reports were identified, which were then annotated in stage 4.
Conclusions:
Smoking cessation annotation methods developed as part of the HBCP were mostly transferable to the physical activity domain. However, the codes applied to behavioural outcome variables required adaptations. This paper can help anyone interested in building a body of research to develop automated evidence synthesis methods in physical activity or for other behaviours.This work was supported by Wellcome [201524; The Human Behaviour-Change Project: Building the science of behaviour change for complex intervention development]. The Human Behaviour-Change Project is funded by a Wellcome Trust collaborative award
Key drivers that influence the provision and sustainability of executive education
Get PDFThis thesis was submitted for the award of Doctor of Education and was awarded by Brunel University LondonExecutive Education (EE) courses are designed for middle to senior managers as part of their continuous professional development (CPD), offering high revenue with courses ranging from a few days to several weeks. Prior to the COVID-19 pandemic, these courses were primarily campus-based, but travel restrictions necessitated a shift to hybrid or online delivery.
Existing literature on EE largely assumes classroom-based learning led by practitioners, with location being a key factor in course selection. However, the pandemic has prompted a transition to technology-dependent, hybrid or remote formats, raising concerns about the relevance and reliability of conventional EE theories. Additionally, there is limited research on how EE supports career progression for individuals with disabilities or spent criminal convictions.
This research, based on applicant data from a UK private EE provider (391 applications between 2019 and 2021) and seven semi-structured staff interviews, provides a unique perspective on how COVID-19 reshaped EE. It examines learner characteristics such as gender, age, education, location, future aspirations, disabilities, and criminal convictions.
While existing theories were largely affirmed, the study revealed novel insights into EE's links with international migration, disability, criminal history, gender, age, and career aspirations. It also shed light on how participants plan to use the knowledge gained after returning to their home countries. The impact of COVID-19 on course delivery and learner expectations was particularly noteworthy.
This research contributes to the fields of EE, international student mobility, and equal opportunities for career progression. It offers recommendations for EE providers and raises questions about the UK’s national policy on English literacy, specifically how it selectively impacts certain countries
Determination of the strong coupling and its running from measurements of inclusive jet production
Get PDF● Data availability - Release and preservation of data used by the CMS Collaboration as the basis for publications is guided by the CMS data preservation, re-use and open access policy (https://opendata.cern.ch/record/415)● Article No.: 139651The value of the strong coupling ₛ is determined in a comprehensive analysis at next-to-next-to-leading order
accuracy in quantum chromodynamics. The analysis uses double-differential cross section measurements from
the CMS Collaboration at the CERN LHC of inclusive jet production in proton-proton collisions at centre-of
mass energies of 2.76, 7, 8, and 13TeV, combined with inclusive deep-inelastic data from HERA. The value
ₛ(Z)=0.1176 +0.0014
−0.0016 is obtained at the scale of the Z boson mass. By using the measurements in different intervals of jet transverse momentum, the running of ₛ is probed for energies between 100 and 1600 GeV.SCOAP³
Marie-Curie programme and The European Research Council and Horizon 2020 Grant, contract Nos. 675440, 724704, 752730, 758316, 765710, 824093, 101115353, 101002207, and COST Action CA16108 (European Union); the Leventis Foundation; The Alfred P. Sloan Foundation; the Alexander von Humboldt Foundation; the Science Committee, project no. 22rl-037 (Armenia); the Belgian Federal Science Policy Office; the Fonds pour la Formation à la Recherche dans l'Industrie et dans l'Agriculture (FRIA-Belgium); the F.R.S.-FNRS and FWO (Belgium) under the “Excellence of Science – EOS” – be.h project n. 30820817; the Beijing Municipal Science & Technology Commission, No. Z191100007219010 and Fundamental Research Funds for the Central Universities (China); The Ministry of Education, Youth and Sports (MEYS) of the Czech Republic; the Shota Rustaveli National Science Foundation, grant FR-22-985 (Georgia); the Deutsche Forschungsgemeinschaft (DFG), among others, under Germany's Excellence Strategy – EXC 2121 “Quantum Universe” – 390833306, and under project number 400140256 - GRK2497; the Hellenic Foundation for Research and Innovation (HFRI), Project Number 2288 (Greece); the Hungarian Academy of Sciences, the New National Excellence Program - ÚNKP, the NKFIH research grants K 131991, K 133046, K 138136, K 143460, K 143477, K 146913, K 146914, K 147048, 2020-2.2.1-ED-2021-00181, TKP2021-NKTA-64, and 2021-4.1.2-NEMZ_KI-2024-00036 (Hungary); the Council of Science and Industrial Research, India; ICSC – National Research Centre for High Performance Computing, Big Data and Quantum Computing and FAIR – Future Artificial Intelligence Research, funded by the NextGenerationEU program (Italy); the Latvian Council of Science; the Ministry of Education and Science, project no. 2022/WK/14, and the National Science Center, contracts Opus 2021/41/B/ST2/01369 and 2021/43/B/ST2/01552 (Poland); the Fundação para a Ciência e a Tecnologia, grant CEECIND/01334/2018 (Portugal); the National Priorities Research Program by Qatar National Research Fund; MCIN/AEI/10.13039/501100011033, ERDF “a way of making Europe”, and the Programa Estatal de Fomento de la Investigación Científica y Técnica de Excelencia María de Maeztu, grant MDM-2017-0765 and Programa Severo Ochoa del Principado de Asturias (Spain); the Chulalongkorn Academic into Its 2nd Century Project Advancement Project, and the National Science, Research and Innovation Fund via the Program Management Unit for Human Resources & Institutional Development, Research and Innovation, grant B39G670016 (Thailand); the Kavli Foundation; the Nvidia Corporation; the SuperMicro Corporation; the Welch Foundation, contract C-1845; and the Weston Havens Foundation (USA)
Enabling by voice: an exploratory study on how interactive smart agents (ISAs) can change the design of environmental control (EC) equipment and service
Get PDFAim:
Well-designed assistive devices improve the quality of life of individuals with severe and permanent impairments and reduce the burden on their caregivers. This study investigated whether interactive smart agents (ISAs) are effective in supporting individuals who are affected by neurological conditions causing severe mobility issues, and the factors aiding ISAs’ adoption.
Materials and Methods:
The North Thames Regional Environmental Control Equipment Services (NTRECES) supported this study by recruiting service users (people with severe mobility impairments due to neurological ailments) in the study. Health Research Authority approval was obtained (255096). NTRECES prescribes medical-grade environmental control (EC) devices, unlike smart speakers (ISAs). Research on ISA adoption by NTRECES users could support prescribing ISAs as assistive EC devices in the future. Through secondary research and exploratory primary data, this user-centred study developed an initial technology adoption model, subsequently revised in light of the insights from a multi-point qualitative primary research.
Conclusion:
This research uncovered that novelty, ease of voice interaction and its entertainment value play a key role in the adoption decision. Willingness to overlook reliability, privacy and security attributes was identified, providing that the service users had back-up devices for security and privacy critical tasks. The originality of this work consists in the development of a technology adoption model tailored to consider the characteristics of service users with severe physical disabilities and the attributes of ISAs technology. The research contributes to the discussion on contextual factors and technology design features that may improve the inclusivity of ISAs and their use as medical devices
Ketamine and other NMDA receptor antagonists for chronic pain
No full textVersion CD015373.pub2Rationale:
N‐methyl‐D‐aspartate (NMDA) receptor antagonists are a group of medicines classed according to their mechanism of action. Ketamine and other NMDA receptor antagonists are used to treat chronic pain, despite uncertain benefits and harms.
Objectives:
To evaluate the benefits and harms of ketamine and other NDMA receptor antagonists compared to placebo, usual care, or other medicines for adults with chronic non‐cancer, non‐headache pain.
Search methods:
We searched CENTRAL, MEDLINE, Embase, and three trial registries (with reference checking, citation searching, and contact with study authors/experts) to identify included studies. The last search was 3 June 2025.
Eligibility criteria:
We included randomised controlled trials (RCTs) in adults with chronic pain (≥ 3 months' duration), evaluating ketamine, memantine, dextromethorphan, amantadine, or magnesium versus placebo, usual care, or another medicine. We excluded studies of cancer or headache pain.
Outcomes:
Critical outcomes were pain intensity and adverse events. Important outcomes were disability, depressive symptoms, health‐related quality of life, tolerability, and opioid consumption.
For adverse events and tolerability, follow‐up was until the end of treatment. For all other outcomes, we were interested in treatment effects in the immediate term (48 hours–1 week), short term (> 1 week–3 months), medium term (> 3 months–6 months), and long term (> 6 months).
Risk of bias:
We assessed risk of bias using the Cochrane Risk of Bias tool for RCTs (RoB 2).
Synthesis methods:
We converted all continuous pain intensity scores to a 0‐to‐100 scale (0 = no pain; 100 = worst pain). We synthesised results using random‐effects meta‐analysis where possible, reporting mean differences (MDs) for continuous outcomes and risk ratios (RRs) for dichotomous outcomes, each with its 95% confidence interval (CI). We assessed the certainty of evidence with GRADE.
Included studies:
We found 67 RCTs (2309 participants): 30 parallel‐group RCTs (1568 participants) and 37 cross‐over RCTs (741 participants). Most studies (96%) were from high‐income countries. Female participation ranged from 11% to 100%. The interventions were ketamine (39 studies), memantine (10 studies), dextromethorphan (9 studies), amantadine (3 studies), and magnesium (8 studies). Sixty‐two studies used placebo comparators. Our quantitative synthesis included 28 studies.
Synthesis of results:
Results are presented for pain intensity (continuous measures, at reported time points) and total adverse events.
Ketamine:
Intravenous ketamine versus placebo
There is no clear evidence that intravenous ketamine reduces pain intensity in the immediate term (MD −15.79, 95% CI −32.09 to 0.51; 3 studies, 173 participants; very low certainty), short term (MD −5.32, 95% CI −15.51 to 4.87; 4 studies, 114 participants; low certainty), or medium term (MD −8.70, 95% CI −31.05 to 13.65; 1 study, 19 participants; very low certainty).
Intravenous ketamine may increase the risk of adverse events (RR 3.26, 95% CI 1.05 to 10.09; 4 studies, 140 participants; low certainty).
Oral ketamine versus placebo
There is no clear evidence that oral ketamine reduces pain intensity in the immediate term (MD −2.64, 95% CI −13.42 to 8.14; 2 studies, 46 participants; low certainty) or short term (MD −9.80, 95% CI −23.55 to 3.95; 2 studies, 40 participants; low certainty).
No studies reported total adverse events.
Topical ketamine versus placebo
There is no clear evidence that topical ketamine reduces pain intensity in the immediate term (MD 1.90, 95% CI −18.73 to 22.53; 1 study, 47 participants; very low certainty) or short term (MD 2.82, 95% CI −14.49 to 20.12; 2 studies, 64 participants; low certainty).
There is no clear evidence that topical ketamine increases the risk of adverse events (RR 1.14, 95% CI 0.47 to 2.73; 1 study, 47 participants; low certainty).
Memantine
Oral memantine versus placebo
There is no clear evidence that oral memantine reduces pain intensity in the immediate term (MD 4.00, 95% CI −9.93 to 17.93; 1 study, 36 participants; very low certainty), short term (MD −8.69, 95% CI −19.40 to 2.02; 6 studies, 217 participants; very low certainty), or medium term (MD −1.74, 95% CI −43.18 to 39.70; 2 studies, 101 participants; very low certainty).
There is no clear evidence that oral memantine increases the risk of adverse events (RR 1.09, 95% CI 0.76 to 1.56; 3 studies, 100 participants; low certainty).
Dextromethorphan
Oral dextromethorphan versus placebo
The evidence is very uncertain about the effect of oral dextromethorphan on pain intensity in the short term (MD −9.00, 95% CI −22.86 to 4.86; 1 study, 40 participants; very low certainty).
The evidence is very uncertain about the risk of adverse events with oral dextromethorphan (RR 1.80, 95% CI 0.73 to 4.43; 1 study, 40 participants; very low certainty).
Amantadine
Oral amantadine versus placebo
The evidence is very uncertain about the effect of oral amantadine on pain intensity in the immediate term (MD 6.00, 95% CI −12.45 to 24.45; 1 study, 26 participants; very low certainty).
The evidence is very uncertain about the risk of adverse events with oral amantadine (RR 0.86, 95% CI 0.14 to 5.20; 1 study, 26 participants; very low certainty).
Magnesium
Intravenous magnesium versus placebo
There is no clear evidence that intravenous magnesium reduces pain intensity in the immediate term (MD −2.00, 95% CI −14.43 to 10.43; 1 study, 55 participants; low certainty) and short term (MD −3.47, 95% CI −15.25 to 8.31; 2 studies, 82 participants; low certainty).
The evidence is very uncertain about the risk of adverse events with intravenous magnesium (0/35 events in intravenous magnesium group versus 0/35 in placebo group; 1 study, 70 participants; very low certainty).
Oral magnesium versus placebo
There is no clear evidence that oral magnesium reduces pain intensity in the short term (MD −0.55, 95% CI −8.32 to 7.21; 2 studies, 118 participants; low certainty).
No studies reported total adverse events.
Authors' conclusions:
Limited low‐ to very low‐certainty evidence limits conclusions about the effects of ketamine, memantine, dextromethorphan, amantadine, and magnesium on pain intensity. Intravenous ketamine may increase the risk of adverse events, but the harms of ketamine and other NMDA receptor antagonists are generally unclear. Adequately powered RCTs are needed to determine the benefits and harms of ketamine and other NMDA receptor antagonists for chronic pain.
Funding:
No dedicated funding.
Registration:
Protocol available: doi.org/10.1002/14651858.CD015373No dedicated funding
Development of an Ontology of Engagement with Behaviour Change Interventions
Get PDFData availability:
Underlying data:
Open Science Framework: Human Behaviour-Change Project. https://doi.org/10.17605/OSF.IO/EFP4X (West et al., 2020): The relevant data can be accessed under the Behavioural Science Component of the registration
This project contains the following underlying data:
- Expert stakeholder feedback on Intervention Engagement Ontology; Raw feedback received from behavioural science and ontology experts; https://osf.io/5jmwx .Extended data:
Open Science Framework: Human Behaviour-Change Project. https://doi.org/10.17605/OSF.IO/EFP4X (West et al., 2020): The relevant data can be accessed under the Behavioural Science Component of the registration
This project contains the following extended data:
Papers used in the development and refinement of ontology classes (Steps 2 and 3) and testing of the application of these classes (Step 5): https://osf.io/mreyj
Expert stakeholder survey; Full survey provided to behaviour science experts in the review in Step 4; https://osf.io/5szcb
The classes hierarchically organised in the Intervention Engagement Ontology at the end of Step 2; https://osf.io/m642s
The classes hierarchically organised in the Intervention Engagement Ontology at the end of Step 3; https://osf.io/9yg5a
Log of responses for stakeholder feedback in Step 4, including decisions on changing aspects of the ontology or rationale for not making changes; https://osf.io/r7jby
The classes hierarchically organised in the Intervention Engagement Ontology at the end of Step 4; https://osf.io/tvebq
Inter-rater reliability testing for annotations by researchers familiar with the Intervention Engagement Ontology in Step 5; https://osf.io/za4jb
Inter-rater reliability testing for annotations by researchers unfamiliar with the Intervention Engagement Ontology in Step 5; https://osf.io/bzpgc
Annotation guidelines; Manual for coding using the Intervention Engagement Ontology; https://osf.io/abg9k
The first published version of the Intervention Engagement Ontology; https://osf.io/tvw9r.
OSF page for the Human Behaviour-Change Project; Homepage for all outputs across the project; https://osf.io/h4sdy/
Zenodo: HumanBehaviourChangeProject/ontologies: https://doi.org/10.5281/zenodo.14882463 (Hastings et al., 2025)
Data and the Engagement Ontology on the GitHub repository are available under the terms of the Creative Commons Attribution 4.0 International license (CC-BY 4.0).Software availability:
Source code used to calculate alpha for IRR available from: https://github.com/HumanBehaviourChangeProject/Automation-InterRater-Reliability.
Archived code at time of publication: https://doi.org/10.5281/zenodo.3833816 (Finnerty & Moore, 2020)
License: GNU General Public License v3.0 onlyBackground:
Participants’ engagement with behaviour change interventions is crucial for their effectiveness. However, engagement is conceptualised and measured inconsistently across research domains, limiting the ability to compare and synthesise evidence about engagement and identify strategies to enhance engagement. This study aimed to develop an ontology—a classification framework—to precisely specify and define aspects of engagement with behaviour change interventions.
Methods:
The Intervention Engagement Ontology was developed in seven steps: (1) specifying the ontology’s scope, (2) reviewing intervention reports to identify key classes (categories) of engagement, (3) refining the ontology through literature annotations, (4) a stakeholder review on the ontology’s clarity and comprehensiveness, (5) testing inter-rater reliability in applying the ontology for annotations, (6) specifying relationships between classes, and (7) making the ontology machine-readable.
Results:
Participant engagement with interventions was defined as “An individual human activity of an intervention participant within one or more parts of the intervention.” Through Steps 1–4, an initial ontology with 48 classes was developed, including 37 engagement-specific and 11 structurally supporting classes (e.g., emotional process). Inter-rater reliability for applying these engagement classes was ‘acceptable’ for researchers familiar (α = 0.71) and unfamiliar (α = 0.78) with the ontology. After further refinements (Steps 6-7), the published ontology included 54 classes - 44 engagement-specific and 10 supporting classes. The engagement classes were structured around three key engagement types: (1) behavioural, (2) emotional, and (3) cognitive. Behavioural engagement aspects, such as frequency and duration, were also represented in the ontology.
Discussion:
The Intervention Engagement Ontology provides a structured framework for specifying and defining participant engagement with behaviour change interventions, facilitating clearer communication, comparison and evidence synthesis across research studies and domains. Future work will refine the ontology based on further feedback and empirical validation, enhancing its applicability.Grant Information: This work is supported by the Wellcome Trust through a collaborative award to the Human Behaviour-Change Project [201524] and the National Institutes of Health through an award to the Advancing Prevention Research In Cancer through Ontology Tools (APRICOT) Project [1U01CA291884-01]
Data sources:
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