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The creation and use of ontologies has become increasingly relevant for complex systems in recent years. This is because of the growing number of use of cases that rely on real-world integration of disparate systems, the need for semantic congruence across boundaries and the expectations of users for conceptual clarity within evolving domains or systems of interest. These needs are evident in most spheres of research involving complex systems, but they are particularly apparent in infrastructure and cities where traditionally siloed and sectoral approaches have dominated, undermining the potential for integration to solve societal challenges such as net zero, resilience to climate change, equity and affordability. This paper reports on findings of a literature review on infrastructure and city ontologies and puts forward some hypotheses inferred from the literature findings. The hypotheses are discussed with reference to the literature and provide avenues for further research on (a) belief systems that underpin non-top-level ontologies and the potential for interference from them, (b) the need for a small number of top-level ontologies and translation mechanisms between them and (c) clarity on the role of standards and information systems in the adaptability and quality of data sets using ontologies. A gap is also identified in the extent that ontologies can support more complex automated coupling and data transformation when dealing with different scales.

With infrastructure systems growing increasingly complex and interdependent, the consequences of a system failure have the potential to be more devastating, and impact more users, than ever before. Self-healing systems, originally proposed as a solution to complexity in software-based systems, are those that can independently identify failure or degradation in the network and generate solutions to restore functionality, allowing the continued provision of services. The benefits of adopting a self-healing approach to infrastructure network management are obvious and abundant; network quality can be assessed and assured, threats can be swiftly identified and dealt with, resources can be assigned to optimise coverage under fluctuating demand and consumers can have confidence in the stability of the services that they use on a daily basis. This paper outlines the potential for self-healing within water infrastructure systems, a sector that has been slow to embrace system-wide approaches. A systematic review of the topic identifies emerging terminology and methods within the water domain, and the extent to which current research aligns with self-healing methodology is discussed. Finally, the steps that can be implemented to shift the water sector towards a self-healing perspective are explored through a case study of leakage management in water pipeline systems.

This research explores the existing definitions, concepts and applications surrounding the efficient implementation and use of digital twins (DTs) within civil infrastructure systems (CISs). The CISs within the scope of this research are as follows: transportation, energy, telecommunications, water and waste, as well as Smart Cities, which encompasses all of the previous. The research methodology consists of a review of current literature, a series of semi-structured interviews and a detailed survey. The outcome of this work is a refined definition of DTs within CISs, in addition to a set of recommendations for both future academic research and industry best practice.

Supplemental Digital Content is available in the text, Objective: To assess the impact of HIV and antiretroviral exposure without infection on lung growth and function over the first 2 years of life. Design: Prospective observational study of an African birth cohort, Drakenstein Child Health Study. Method: Infants enrolled antenatally had lung function measured at 6 weeks, 1 and 2 years. HIV-infected women received antiretroviral therapy (ART) as per local guidelines. The association between HIV and antiretroviral exposure with lung function was assessed using mixed effects modelling. Results: Of 1143 infants born, two HIV-infected infants were excluded from analysis; 909 (80%) infants had lung function collected at 6 weeks [190 (21%) were HIV-exposed uninfected (HEU)]; 782 (69%) at 1 year and 741 (65%) at 2 years. At 6 weeks HEU infants had larger tidal volume compared with HIV-unexposed infants (1.13 ml, confidence interval: 0.02–2.23, P = 0.045). High maternal viral load was associated with a 17% lower expiratory flow over 2 years (0.17, confidence interval 0.00–0.34, P = 0.046). First-line ART initiated during pregnancy was associated with lower infant tidal volume at 6 weeks compared with those who initiated ART before pregnancy (−2.7 ml, −5.31 to −0.10, P = 0.042), and low maternal CD4+ cell counts associated with lower infant tidal over 2 years (−11.1 ml, −18.58–3.58, P = 0.004). Conclusion: HIV exposure is associated with altered lung function in early life, with a vulnerable HEU subgroup based on maternal disease severity, immunological compromise and ART exposure. These data highlight the importance of ongoing surveillance of respiratory health in HEU children.

Background: Lower respiratory tract illness (LRTI) in infancy reduces lung function at 1 year, independent of baseline lung function. Aim: To assess whether the impact of LRTI in infancy on lung function persists to 2 years. Methods: Lung function was measured using tidal breathing, multiple breath washout and the forced oscillation technique at 6 weeks, 1 and 2 years, in a South African birth cohort (Drakenstein Child Health Study). Study staff confirmed LRTI. The association between LRTI and lung function during 2 years was assessed using mixed effect models with random subject effects, adjusted for age, BMI for age Z-score, sex, ethnicity, SES quartile at birth and gestational age. Results: 858 infants (male 52%, HIV exposed 21%, Black African: 52.5%, maternal smoking 33%) were tested at six weeks; 632 (74%) at one and 620 (72%) at two years. 475 children had 872 episodes of LRTI during 2 years. Children who had an LRTI had a higher respiratory rate (RR 4 % change, CI 0.01, 0.05; p=0.002) and lung clearance index (LCI 0.05, CI 0.00, 0.10; p=0.046) and a lower tidal volume (TV -1.5mL, CI-2.9,-0.2; p=0.03) and compliance (-0.49 mL.hPa-1, CI -0.9,-0.04; p=0.03) at 2 years vs. those without LRTI. The effect was stronger with each further LRTI episode (RR further 1% increase, p=002; TV -0.5ml, p=0.01; LCI 0.02, p=0.03; time to peak expiratory flow over total expiratory time ratio: tPTEF/tE -0.01, p=0.03) or associated with wheeze (LCI 0.06, p=0.04; tPTEF/tE -0.07, p=0.002). Conclusion: LRTI in infancy has a sustained impact on lung function at 2 years, especially if recurrent or associated with wheeze. Funding: The Wellcome Trust (204755/Z/16/Z) Bill and Melinda Gates Foundation (1017641)

Lower respiratory tract illness (LRTI) is a leading cause of mortality and morbidity in children. Sensitive and noninvasive infant lung function techniques are needed to measure risk for and impact of LRTI on lung health. The objective of this study was to investigate whether lung function derived from the intra-breath forced oscillation technique (FOT) was able to identify healthy infants at risk of LRTI in the first year of life. Lung function was measured with the novel intra-breath FOT, in 6-week-old infants in a South African birth cohort (Drakenstein Child Health Study). LRTI during the first year was confirmed by study staff. The association between baseline lung function and LRTI was assessed with logistic regression and odds ratios determined using optimal cut-off values. Of the 627 healthy infants with successful lung function testing, 161 (24%) had 238 LRTI episodes subsequently during the first year. Volume dependence of respiratory resistance (ΔR) and reactance (ΔX) was associated with LRTI. The predictive value was stronger if LRTI was recurrent (n=50 (31%): OR 2.5, ΔX), required hospitalisation (n=38 (16%): OR 5.4, ΔR) or was associated with wheeze (n=87 (37%): OR 3.9, ΔX). Intra-breath FOT can identify healthy infants at risk of developing LRTI, wheezing or severe illness in the first year of life., Novel measurements of respiratory mechanics are feasible in infants in a community setting and able to detect changes in lung function in healthy infants associated with increased risk of subsequent LRTI in infancy http://ow.ly/IUKk30mCfi3