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[In Press] Distributed secure filtering against eavesdropping attacks in SINR-based sensor networks
No full textThis paper focuses on the design of a privacy-preserving distributed Kalman filtering algorithm for a class of linear time-varying systems in signal-to-interference-plus-noise ratio (SINR)-based sensor networks, where packet dropouts may occur in information transmission between neighboring sensor nodes. Considering the potential occurrence of eavesdropping attacks during information transmission, which is common due to the inherent vulnerability of SINR-based sensor networks, a new class of distributed secure Kalman filtering algorithm has been developed. The presented algorithm incorporates a modified ElGamal cryptosystem and adaptive fusion weights to significantly enhance security, resist privacy leakage, and bolster robustness against packet dropping. Then, a detailed performance analysis for the presented distributed secure Kalman filtering algorithm is conducted, where the security and unbiasedness of the designed algorithm are discussed. Sufficient conditions for the stability of the estimation error are further established to ensure that the estimation error is ultimately bounded in the almost sure sense. Finally, numerical examples are given to illustrate the effectiveness of the proposed algorithm
Low-flow identification in flood frequency analysis : a case study for eastern Australia
No full textDesign flood estimation is an essential step in many water engineering design tasks such as the planning and design of infrastructure to reduce flood damage. Flood frequency analysis (FFA) is widely used in estimating design floods when the at-site flood data length is adequate. One of the problems in FFA with an annual maxima (AM) modeling approach is deciding how to handle smaller discharge values (outliers) in the selected AM flood series at a given station. The objective of this paper is to explore how the practice of censoring (which involves adjusting for smaller discharge values in FFA) affects flood quantile estimates in FFA. In this regard, two commonly used probability distributions, log-Pearson type 3 (LP3) and generalized extreme value distribution (GEV), are used. The multiple Grubbs and Beck (MGB) test is used to identify low-flow outliers in the selected AM flood series at 582 Australian stream gauging stations. It is found that censoring is required for 71% of the selected stations in using the MGB test with the LP3 distribution. The differences in flood quantile estimates between LP3 (with MGB test and censoring) and GEV distribution (without censoring) increase as the return period reduces. A modest correlation is found (for South Australian catchments) between censoring and the selected catchment characteristics (correlation coefficient: 0.43), with statistically significant associations for the mean annual rainfall and catchment shape factor. The findings of this study will be useful to practicing hydrologists in Australia and other countries to estimate design floods using AM flood data by FFA. Moreover, it may assist in updating Australian Rainfall and Runoff (national guide)
Effect of silica fume type on rheology and compressive strength of geopolymer mortar
No full textSilica fume (SF) is widely used in the developing of high-performance geopolymer systems. Previous studies have shown that using different types of SF may have different influences on the performance of geopolymers. What are the key factors (affecting the properties of geopolymers) still need to be clarified? This paper investigated the effects of three types of silica fume (SF1− SF3) with various silica contents (98.0%, 94.7% and 53.1%) and particle sizes (D50: 3.3 μm, 3.1 μm and 11.8 μm) on the rheology and compressive strength of alkali-activated calcium alumina cement (CAC)/fly ash mortar. The incorporation of SF can significantly increase the plastic viscosity. The increase in plastic viscosity was due to the ball-bearing action of the spherical SF particles, which reduced the friction between the particles under shearing. Replacing 20% of the fly ash with SF1 and SF2 improved the compressive strength of geopolymer mortars while the incorporation of SF3 decreased the compressive strength at the same replacement ratio. Inductively coupled plasma (ICP) spectrometry results indicated that the amorphous silica in the SFs was dissolved in an alkali solution. Activators with high concentrations of monomer and dimmer silicon groups may promote the reaction between precursors and activators. The formation of additional aluminosilicate gels reduced the amount of large capillary pores (500 nm to 1000 nm), leading to improved strength. The incorporation of coarse SF3 introduced extra voids in the mixture, as suggested by calculations of packing density, leading to reduced strength
Comparative utility of the DSM-5 and ICD-11 diagnostic classifications of eating disorders of recurrent binge eating in an Australian community-based sample
No full textObjective: The present study aimed to compare the estimated prevalence, sociodemographic features and impacts of Bulimia Nervosa (BN), Binge Eating Disorder (BED) and Other Specified Feeding or Eating Disorder (OSFED; BN or BED of low frequency and/or limited duration) when comparing the DSM-5 with the broader ICD-11 diagnostic criteria for size and specifiers of binge-eating episodes in a general population epidemiological sample. Methods: 2977 individuals (1524 women and 1453 men) aged ≥15Â years from randomly selected households in South Australia were interviewed in person. Participants were asked questions relating to sociodemographic features, symptoms of eating disorder pathology, physical and mental health-related quality of life (HRQoL; SF-12) and role impairment. Results: The estimated prevalence of only one diagnosis, namely BED, was lower when applying DSM-5 criteria than when applying ICD-11 criteria, largely due to the Criterion B binge-eating specifiers of the DSM-5. There were no significant differences in participants' demographic features, HRQoL, or role impairment between the comparable diagnosis of either scheme. Conclusions: There were few differences in distribution and similar levels of health impacts when applying either diagnostic scheme in this epidemiological study. However, cases of BED may be missed when using the stricter criteria of DSM-5 in epidemiological surveys. Further studies are needed to assess the clinical utility of the DSM-5 and ICD-11 diagnostic specifiers of binge-eating
Telehealth use in maternity care during a pandemic : a lot of bad, some good and possibility
No full textBackground: To reduce transmission risk during the COVID-19 pandemic, ‘telehealth’ (health care delivered via telephone/video-conferencing) was implemented into Australian maternity services. Whilst some reports on telehealth implementation ensued, there was scant evidence on women and midwives’ perspectives regarding telehealth use. Methods: A qualitative study was conducted in Australia during 2020–2021 using two data sources from the Birth in the Time of COVID-19 (BITTOC) study: i) interviews and ii) surveys (open-text responses). Content analysis was utilised to analyse the data and explore telehealth from the perspective of midwives and women accessing maternity care services. In-depth interviews were conducted with 20 women and 16 midwives. Survey responses were provided from 687 midwives and 2525 women who were pregnant or gave birth in 2021, generating 212 and 812 comments respectively. Findings: Telehealth delivery was variable nationally and undertaken primarily by telephone/videoconferencing. Perceived benefits included: reduced COVID-19 transmission risk, increased flexibility, convenience and cost efficiency. However, women described inadequate assessment, and negative impacts on communication and rapport development. Midwives had similar concerns and also reported technological challenges. Conclusion: During the COVID-19 pandemic, telehealth offered flexibility, convenience and cost efficiency whilst reducing COVID-19 transmission, yet benefits came at a cost. Telehealth may particularly suit women in rural and remote areas, however, it also has the potential to further reduce equitable, and appropriate care delivery for those at greatest risk of poor outcomes. Telehealth may play an adjunct role in post-pandemic maternity services, but is not a suitable replacement to traditional face-to-face maternity care
[In Press] A longitudinal examination of language learners' group-level enjoyment and emotion regulation in online collaborative learning
No full textThis study examines the evolution and regulation of group-level enjoyment of online collaborative language learning. Three Chinese undergraduate learners of English as a foreign language (EFL) collaborated to finish a series of English writing tasks via an online group enabled by WeChat, a popular social instant messaging app in Chinese-speaking communities. The data were collected in three sessions over a single semester using an idiodynamic approach for participants’ ratings of enjoyment intensity and stimulated recall interviews for participants’ descriptions of emotion regulation types. The data were analysed using deductive qualitative thematic analysis and quantitative descriptive analysis. The findings indicate that group-level enjoyment fluctuated within each session of online collaborative learning and tended to last longer in later sessions. Furthermore, the participants reported enacting three different types of regulation – namely self-regulation, co-regulation, and socially shared regulation – to achieve and sustain the dynamic evolution of group-level enjoyment in online collaborative learning. Of these, socially shared regulation was the most prevalent overall, and this increased in prevalence with time. The findings also reveal specific emotion regulation processes within these three types, including planning, evaluating, and the use of emojis. The implications of the findings are discussed, and future research directions are provided
Childhood obesity prevention in general practice : supporting implementation through co-ideation
No full textBackground: Childhood obesity is associated with physical and psychological complications thus the prevention of excess weight gain in childhood is an important health goal. Relevant to the prevention of childhood obesity, Australian general practice-specific, preventive care guidelines recommend General Practitioners (GPs) conduct growth monitoring and promote a number of healthy behaviours. However, challenges to providing preventive care in general practice may impact implementation. In October and November, 2022, a series of three workshops focusing on the prevention of childhood obesity were held with a group of Australian GPs and academics. The objective of the workshops was to determine practical ways that GPs can be supported to address barriers to the incorporation of obesity-related prevention activities into their clinical practice, for children with a healthy weight. Methods: This paper describes workshop proceedings, specifically the outcomes of co-ideation activities that included idea generation, expansion of the ideas to possible interventions, and the preliminary assessment of these concepts. The ecological levels of the individual, interpersonal, and organisation were considered. Results: Possible opportunities to support childhood obesity prevention were identified at multiple ecological levels within the clinic. The preliminary list of proposed interventions to facilitate action included GP education and training, clinical audit facilitation, readily accessible clinical guidelines with linked resources, a repository of resources, and provision of adequate growth monitoring tools in general practice. Conclusions: Co-ideation with GPs resulted in a number of proposed interventions, informed by day-to-day practicalities, to support both guideline implementation and childhood obesity prevention in general practice
Learning spatial affordances from 3D point clouds for mapping unseen human actions in indoor environments
No full textMany indoor robots operate in environments designed to support human activities. Understanding probable human actions in such surroundings is crucial for facilitating better human-robot interactions. This article presents an innovative approach to map unseen human actions in indoor environments by leveraging spatial affordances learned from geometric features extracted from point clouds captured by 3D cameras. Instead of directly observing real people to understand human context, the method utilizes virtual human models and their interactions with the environment to uncover hidden human affordances. This approach proves to be efficient for learning the affordance map, even when dealing with highly imbalanced datasets. To achieve this, we employ a supervised learning model optimized for the F1 score, using the Structured-SVM (S-SVM) architecture. We conducted experiments with actual 3D scenes, evaluating various affordance types both qualitatively and quantitatively. The results show that the proposed S-SVM-based method outperforms other models, demonstrating its effectiveness in efficiently mapping human context in indoor environments. The S-SVM-based method outperformed other models, demonstrating efficient human context mapping in indoor environments
Modelling of flexural fatigue behaviours of hybrid engineered cementitious composite link slabs using cycle-driven analysis
No full textLink slabs are designed and expected to be serviced under high-cycle traffic loadings. Although their high-cycle fatigue performance is critical in their practical applications, very few experimental and numerical studies have been conducted to study high-cycle fatigue failure of link slabs due to the huge amount of time and resources needed for fatigue tests and the lack of efficient modelling method for high-cycle fatigue failure. Recently, as a newly developed material with superior mechanical properties, the hybrid fibre reinforced engineered cementitious composite (hybrid ECC) has been recommended for link slab application. In this study, a novel and efficient cycle-driven analysis (CDA) procedure was developed to model the structural behaviour of ECC link slabs made of the hybrid ECC under high-cycle fatigue loadings, which is the first attempt for CDA to be applied in high-cycle fatigue structural modelling of a hybrid ECC link slab with reinforcement bars. In the proposed CDA, fatigue damages of both hybrid ECC and reinforcement bars were taken into account. The accuracy and reliability of the new CDA procedure were validated by comparing the modelling predictions with the experimental results on two quarter-scaled hybrid ECC link slabs. It was found that the proposed CDA procedure could predict the overall fatigue behaviours including the deflection histories, crack patterns, fatigue life, fatigue failure mode and the residual static strength of the hybrid ECC link slabs after fatigue damage with good accuracy
Why aviation English is not ELF
No full textBecause English is the official language of international aviation communication, Aviation English is commonly viewed as a type of English as a lingua franca: It is widely used across the world, the users are mainly second language speakers of English, it differs from standard forms of English in multiple ways, and first language speakers of English often struggle to adhere to its norms (so-called Standard Phraseology and Plain English). There are, however, good reasons to resist labelling it as a lingua franca: It is not so much an emergent form of language use as a highly regulated set of practices; it is a limited repertoire rather than a set of unbounded linguistic resources, and this repertoire is common across languages. It is therefore better understood as communication in aviation rather than communication in English. This observation has important implications not only for the teaching and use of language in aviation contexts but also for an understanding of ELF and applied linguistics more generally, since it raises questions about the effects of using labels such as ‘English’ in discussions of communication and reverses the priority we give to questions of communication in relation to particular languages