266 research outputs found

    Where is the end of a Bridge (model)?

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    Bridge SHM solutions have been developed to assist with the assessment and monitoring of bridges. State of the art bridge SHM solutions tend to be data based, where machine learning algorithms are trained using large, historical bridge datasets, and outlier analysis is subsequently used for anomaly detection. However, most bridges lack the required healthy state data for machine learning approaches to be considered, and many bridges are not in a healthy condition to collect the required data from. A population based structural health monitoring (PBSHM) approach has recently been proposed that seeks to facilitate knowledge transfer between similar structures. The approach proposes that if two structures are similar enough, there could be scope to make SHM inferences between the structures. The ability to make inferences between bridges, which are currently monitored in isolation, would be highly valuable as a bridge management tool, particularly if datasets could be leveraged between bridges through transfer learning. However, before knowledge can be shared between bridges, there is first a need to identify bridges that are similar enough for inferences to be made. The PBSHM approach proposes the use of Irreducible Element (IE) models to describe structures, which allows Attributed Graphs (AG) to generated and compared for similarity using graph theory techniques. The general method for comparing structures was trialled on bridges previously, however the resulting similarity metrics were for the whole bridge as opposed to particular common zones of interest e.g. the deck. This paper instead proposes that bridges be modelled as subsections of structures that interact via shared boundaries (i.e., points of articulation such as bearings), as opposed to whole structures. Bridge datasets are often limited to the part of the bridge that was investigated, i.e., datasets particular to bridge decks, abutments etc. Therefore, the extents of the IE models proposed in this paper are set to only include elements that would pertain to a particular dataset. In particular, two beam and slab bridges are each described with bridge deck, abutment and pier IE models to trial the concept. The revised extents of the bridge IE models reduced the number of elements being compared, resulting in increased resolution graph comparisons being carried out and more meaningful similarity metrics between the bridge parts being achieved

    To Ban or Not to Ban: Foreign Lobbying and Cross National Externalities

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    This paper studies the costs and benefits of foreign lobbying. We show how and when foreign lobbying can help internalize cross national externalities. We argue that this is an often overlooked benefit of foreign lobbying. We also study under what conditions a constitutional rule banning foreign lobbying is in the national interest of a country. A key factor in this calculus is whether the interests of foreign lobby groups and domestic unorganized groups coincide or not. We illustrate the logic with examples from trade policy and environmental regulation

    The effect of education on dental service utilization patterns in different sectors: A multiple mediation analysis.

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    OnlinePublOBJECTIVE: The aim of this study was to investigate how education level affects dental service utilization patterns in the Australian adult population. This study tested how education level mediated these service patterns through behavioural mediators such as smoking, tooth brushing and oral health status and investigated these mediation effects in different dental service providers. METHOD: Following the flexible mediation approach, the direct and indirect effects of education through behavioural mediators on dental service utilization patterns (time of last dental visit, reason for last dental visit and frequency of seeking dental care) were calculated for the South Australian population from the Dental Care and Oral Health Study. RESULTS: Participants with lower educational attainment were 33% (Odds Ratio: 0.67, 95% CI 0.56-0.78) and 38% (Odds Ratio: 0.62, 95% CI 0.53-0.74), less likely than their counterparts with higher education to visit a dentist or to receive dental care in the last 12 months, respectively. Low education was associated with a 23% increase in odds of receiving emergency and treatment services (Odds Ratio: 1.23, 95% CI 1.05-1.43) compared to routine dental check-ups or examinations. CONCLUSION: Low education, regardless of oral health behaviours and status, reduces the odds of dental service utilization in terms of frequency of seeking dental care and time of last dental visit. There is more tendency towards receiving emergency and treatment services compared to routine dental check-ups or examinations in participants with lower educational attainment.Arash Ghanbarzadegan, Murthy Mittinty, David S. Brennan, Lisa M. Jamieso

    The Practice of Dentistry by Australian- and Overseas- Trained Dentists in Australia: Discriminant Analysis of key Predictors

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    Available online 18 February 2021INTRODUCTION: Overseas-trained dentists comprise at least one-fourth of the overall Australian dental workforce. This study examined characteristics and practice differences between Australian- and overseas-trained dentists to identify key predictors that best differentiate their dentistry practices. METHODS: Data for the study were from the Longitudinal Study of Dentist Practice Activity (LSDPA), a survey of a nationally representative random sample of dentists in Australia commencing in 1983-1984 and repeated every 5 years. Dentists were surveyed on a wide range of items including participant characteristics, practice patterns, practice inputs, direct demand, and productivity measures. Data were weighted to provide national estimates by age, sex, and practice type. Discriminant function analysis was used to examine the predictor variables that best distinguished between the two groups. Analysis was limited to the most recent wave of the study. RESULTS: A total of 1148 dentists (response rate = 67%) responded to the survey in 2009-2010; 648 cases were available for the discriminant analysis. The discriminant functions for the full sample and each of the 3 age groups (<35 years; 35-50 years; and 50+ years) were found effective to separate dentists into 2 groups (Australian and overseas), with the proportion of cases correctly classified being highest for the oldest age group (89.7% for 50+ years). Female gender, type of practice (working in public sector), and working in disadvantaged areas were significant predictors, with more prominence in the 35- to 50-year age group. Practice inputs, demand, and productivity measures offered less discriminative capacity between the dentists. CONCLUSION: Overseas-trained dentists contribute towards providing dental care to underserved populations, the public sector, and in rural and remote locations. This study provided basis to argue that policies to encourage overseas-trained dentists to contribute towards areas of need locations have been successful, and key productivity measures were also similar to Australian-trained dentists.Madhan Balasubramanian, A. John Spencer, Woosung Sohn, David S. Brenna

    On the application of population-based structural health monitoring in aerospace engineering

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    One of the major obstacles to the widespread uptake of data-based Structural Health Monitoring so far, has been the lack of damage-state data for the (mostly high-value) structures of interest. To address this issue, a methodology for sharing data and models between structures has been developed–Population-Based Structural Health Monitoring (PBSHM). PBSHM works on the principle that, if populations of structures are sufficiently similar, or share sections which can be considered similar, then data and models can be shared between them for use in diagnostic inference. The PBSHM methodology therefore relies on two key components: firstly, identifying whether structures are sufficiently similar for successful transfer of diagnostics; this is achieved by the use of an abstract representation of structures. Secondly, machine learning techniques are exploited to effectively transfer information between the structures in a way that improves damage detection and classification across the whole population. Although PBSHM has been conceived to deal with large and general classes of structures, much of the detailed developments presented so far have concerned bridges; the aim of this paper is to provide similarly detailed discussions in the aerospace context. The overview here will examine data transfer between aircraft components, as well as illustrating how one might construct an abstract representation of a full aircraft

    Competition between Allowed and First-Forbidden β Decay: The Case of Hg 208 → Tl 208

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    6 pags., 4 figs., 1 tab.The β decay of Hg208 into the one-proton hole, one neutron-particle Tl81208127 nucleus was investigated at CERN-ISOLDE. Shell-model calculations describe well the level scheme deduced, validating the proton-neutron interactions used, with implications for the whole of the N>126, Z<82 quadrant of neutron-rich nuclei. While both negative and positive parity states with spin 0 and 1 are expected within the Qβ window, only three negative parity states are populated directly in the β decay. The data provide a unique test of the competition between allowed Gamow-Teller and Fermi, and first-forbidden β decays, essential for the understanding of the nucleosynthesis of heavy nuclei in the rapid neutron capture process. Furthermore, the observation of the parity changing 0+→0-β decay where the daughter state is core excited is unique, and can provide information on mesonic corrections of effective operators.This work was supported by the European Union under Contracts No. 262010 (ENSAR) and No. 654002 (ENSAR2), the Science and Technology Facilities Council (UK), the German BMBF under Contract No. 05P18PKCIA and “Verbundprojekt 05P2018,” the MINECO Projects No. FPA2015-65035-P, No. RTI2018- 098868-B-I00, No. FPA2015-64969-P, and No. FPA2017- 87568-P (Spain), FWO-Vlaanderen (Belgium), GOA/ 2015/010 (BOF KU Leuven), the Excellence of Science programme (EOS-FWO), the Interuniversity Attraction Poles Programme initiated by the Belgian Science Policy Office (BriX network P7/12), the Romanian IFA project CERN-RO/ISOLDE and the Polish National Science Centre under Contracts No. UMO-2015/18/M/ST2/00523 and No. UMO-2019/33/N/ST2/03023. P. H. R. and S. M. J. acknowledge support from the UK Department for Business, Energy and Industrial Strategy via the National Measurement Office. Zs. P. acknowledges support from the ExtreMe Matter Institute EMMI at the GSI Helmholtzzentrum fr Schwerionenforschung, Darmstadt, Germa

    Strong one-neutron emission from two-neutron unbound states in β decays of the r -process nuclei Ga 86,87

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    β-delayed one-neutron and two-neutron branching ratios (P1n and P2n) have been measured in the decay of A=84 to 87 Ga isotopes at the Radioactive-Isotope Beam Factory (RIBF) at the RIKEN Nishina Center using a high-efficiency array of He3 neutron counters (BRIKEN). Two-neutron emission was observed in the decay of Ga84,85,87 for the first time and the branching ratios were measured to be P2n=1.6(2)%,1.3(2)%, and 10.2(28)stat(5)sys%, respectively. One-neutron branching ratio of Ga87(P1n=81(9)stat(8)sys%) and half-life of 29(4) ms were measured for the first time. The branching ratios of Ga86 were also measured to be P1n=74(2)stat(8)sys% and 16.2(9)stat(6)sys% with better precision than a previous study. The observation that P1n>P2n for both Ga86,87 was unexpected and is interpreted as a signature of dominating one-neutron emission from the two-neutron unbound excited states in Ge86,87. In order to interpret the experimental results, shell-model and Hauser-Feshbach statistical model calculations of delayed particle and γ-ray emission probabilities were performed. This model framework reproduces the experimental results. The shell model alone predicts P2n significantly larger than P1n for the Ga87 decay, and it is necessary to invoke a statistical description to successfully explain the observation that P1n>P2n. Our new results demonstrate the relevance and importance of a statistical description of neutron emission for the prediction of the decay properties of multineutron emitters and that it must be included in the r-process modeling

    First -decay spectroscopy of and new -decay branches of

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    19 pags., 14 figs., 3 tabs.The  decay of the neutron-rich and was investigated experimentally in order to provide new insights into the nuclear structure of the tin isotopes with magic proton number above the shell. The -delayed -ray spectroscopy measurement was performed at the ISOLDE facility at CERN, where indium isotopes were selectively laser-ionized and on-line mass separated. Three -decay branches of were established, two of which were observed for the first time. Population of neutron-unbound states decaying via rays was identified in the two daughter nuclei of and , at excitation energies exceeding the neutron separation energy by 1 MeV. The -delayed one- and two-neutron emission branching ratios of were determined and compared with theoretical calculations. The -delayed one-neutron decay was observed to be dominant -decay branch of even though the Gamow-Teller resonance is located substantially above the two-neutron separation energy of . Transitions following the  decay of are reported for the first time, including rays tentatively attributed to . In total, six new levels were identified in on the basis of the coincidences observed in the and decays. A transition that might be a candidate for deexciting the missing neutron single-particle state in was observed in both  decays and its assignment is discussed. Experimental level schemes of and are compared with shell-model predictions. Using the fast timing technique, half-lives of the , and levels in were determined. From the lifetime of the state measured for the first time, an unexpectedly large transition strength was deduced, which is not reproduced by the shell-model calculations.M.P.-S. acknowledges the funding support from the Polish National Science Center under Grants No. 2019/33/N/ST2/03023 and No. 2020/36/T/ST2/00547 (Doctoral scholarship ETIUDA). J.B. acknowledges support from the Universidad Complutense de Madrid under the Predoctoral Grant No. CT27/16- CT28/16. This work was partially funded by the Polish National Science Center under Grants No. 2020/39/B/ST2/02346, No. 2015/18/E/ST2/00217, and No. 2015/18/M/ST2/00523, by the Spanish government via Projects No. FPA2017-87568-P, No. RTI2018-098868-B-I00, No. PID2019-104390GB-I00, and No. PID2019-104714GB-C21, by the U.K. Science and Technology Facilities Council (STFC), the German BMBF under Contract No. 05P18PKCIA, by the Portuguese FCT under the Projects No. CERN/FIS-PAR/0005/2017, and No. CERN/FIS-TEC/0003/2019, and by the Romanian IFA Grant CERN/ISOLDE. The research leading to these results has received funding from the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No. 654002. M.Str. acknowledges the funding from the European Union’s Horizon 2020 research and innovation program under Grant Agreement No. 771036 (ERC CoG MAIDEN). J.P. acknowledges support from the Academy of Finland (Finland) with Grant No. 307685. Work at the University of York was supported under STFC Grants No. ST/L005727/1 and No. ST/P003885/1

    Use of SMS texts for facilitating access to online alcohol interventions: a feasibility study

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    A41 Use of SMS texts for facilitating access to online alcohol interventions: a feasibility study In: Addiction Science & Clinical Practice 2017, 12(Suppl 1): A4

    Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

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    The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR
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