75 research outputs found

    Identifying cause-and-effect relationships of manufacturing errors using sequence-to-sequence learning

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    In car-body production the pre-formed sheet metal parts of the body are assembled on fully-automated production lines. The body passes through multiple stations in succession, and is processed according to the order requirements. The timely completion of orders depends on the individual station-based operations concluding within their scheduled cycle times. If an error occurs in one station, it can have a knock-on effect, resulting in delays on the downstream stations. To the best of our knowledge, there exist no methods for automatically distinguishing between source and knock-on errors in this setting, as well as establishing a causal relation between them. Utilizing real-time information about conditions collected by a production data acquisition system, we propose a novel vehicle manufacturing analysis system, which uses deep learning to establish a link between source and knock-on errors. We benchmark three sequence-to-sequence models, and introduce a novel composite time-weighted action metric for evaluating models in this context. We evaluate our framework on a real-world car production dataset recorded by Volkswagen Commercial Vehicles. Surprisingly we find that 71.68% of sequences contain either a source or knock-on error. With respect to seq2seq model training, we find that the Transformer demonstrates a better performance compared to LSTM and GRU in this domain, in particular when the prediction range with respect to the durations of future actions is increased

    The impact and significance of tephra deposition on a Holocene forest environment in the North Cascades, Washington, USA.

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    © 2016 Elsevier Ltd. High-resolution palaeoecological analyses (stratigraphy, tephra geochemistry, radiocarbon dating, pollen and ordination) were used to reconstruct a Holocene vegetation history of a watershed in the Pacific Northwest of America to evaluate the effects and duration of tephra deposition on a forest environment and the significance of these effects compared to long-term trends. Three tephra deposits were detected and evaluated: MLF-T158 and MLC-T324 from the climactic eruption of Mount Mazama, MLC-T480 from a Late Pleistocene eruption of Mount Mazama and MLC-T485 from a Glacier Peak eruption. Records were examined from both the centre and fringe of the basin to elucidate regional and local effects. The significance of tephra impacts independent of underlying long-term trends was confirmed using partial redundancy analysis. Tephra deposition from the climactic eruption of Mount Mazama approximately 7600 cal. years BP caused a significant local impact, reflected in the fringe location by changes to open habitat vegetation (Cyperaceae and Poaceae) and changes in aquatic macrophytes (Myriophyllum spicatum, Potamogeton, Equisetum and the alga Pediastrum). There was no significant impact of the climactic Mazama tephra or other tephras detected on the pollen record of the central core. Changes in this core are potentially climate driven. Overall, significant tephra fall was demonstrated through high resolution analyses indicating a local effect on the terrestrial and aquatic environment, but there was no significant impact on the regional forest dependent of underlying environmental changes

    Shared genome analyses of notable listeriosis outbreaks, highlighting the critical importance of epidemiological evidence, input datasets and interpretation criteria

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    The persuasiveness of genomic evidence has pressured scientific agencies to supplement or replace well-established methodologies to inform public health and food safety decision-making. This study of 52 epidemiologically defined Listeria monocytogenes isolates, collected between 1981 and 2011, including nine outbreaks, was undertaken (1) to characterize their phylogenetic relationship at finished genome-level resolution, (2) to elucidate the underlying genetic diversity within an endemic subtype, CC8, and (3) to re-evaluate the genetic relationship and epidemiology of a CC8-delimited outbreak in Canada in 2008. Genomes representing Canadian Listeria outbreaks between 1981 and 2010 were closed and manually annotated. Single nucleotide variants (SNVs) and horizontally acquired traits were used to generate phylogenomic models. Phylogenomic relationships were congruent with classical subtyping and epidemiology, except for CC8 outbreaks, wherein the distribution of SNV and prophages revealed multiple co-evolving lineages. Chronophyletic reconstruction of CC8 evolution indicates that prophage-related genetic changes among CC8 strains manifest as PFGE subtype reversions, obscuring the relationship between CC8 isolates, and complicating the public health interpretation of subtyping data, even at maximum genome resolution. The size of the shared genome interrogated did not change the genetic relationship measured between highly related isolates near the tips of the phylogenetic tree, illustrating the robustness of these approaches for routine public health applications where the focus is recent ancestry. The possibility exists for temporally and epidemiologically distinct events to appear related even at maximum genome resolution, highlighting the continued importance of epidemiological evidence

    The Fermi-LAT Light Curve Repository

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    The Fermi Large Area Telescope (LAT) light curve repository (LCR) is a publicly available, continually updated library of gamma-ray light curves of variable Fermi-LAT sources generated over multiple timescales. The Fermi-LAT LCR aims to provide publication-quality light curves binned on timescales of 3 days, 7 days, and 30 days for 1525 sources deemed variable in the source catalog of the first 10 years of Fermi-LAT observations. The repository consists of light curves generated through full likelihood analyses that model the sources and the surrounding region, providing fluxes and photon indices for each time bin. The LCR is intended as a resource for the time-domain and multi-messenger communities by allowing users to quickly search LAT data to identify correlated variability and flaring emission episodes from gamma-ray sources. We describe the sample selection and analysis employed by the LCR and provide an overview of the associated data access portal.Comment: Accepted for publication in ApJ Supplement Serie

    Volcanic impacts on the Holocene vegetation history of Britain and Ireland? A review and meta-analysis of the pollen evidence

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    Volcanic ash layers show that the products of Icelandic volcanism reached Britain and Ireland many times during the Holocene. Historical records suggest that at least one eruption, that of Laki in a.d. 1783, was associated with impacts on vegetation. These results raise the question: did Icelandic volcanism affect the Holocene vegetation history of Britain and Ireland? Several studies have used pollen data to address this issue but no clear consensus has been reached. We re-analyse the palynological data using constrained ordination with various representations of potential volcanic impacts. We find that the palynological evidence for volcanic impacts on vegetation is weak but suggest that this is a case of absence of evidence and is not necessarily evidence of absence of impact. To increase the chances of identifying volcanic impacts, future studies need to maximise temporal resolution, replicate results, and investigate a greater number of tephras in a broader range of locations, including more studies from lake sediments

    COP-AF

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    Background Higher levels of inflammatory biomarkers are associated with an increased risk of perioperative atrial fibrillation (AF) and myocardial injury after noncardiac surgery (MINS). Colchicine is an anti-inflammatory drug that may prevent these complications. Methods We performed an international, randomised trial at 45 sites in 11 countries. Patients aged ≥55 years and undergoing major noncardiac thoracic surgery were randomised to receive oral colchicine 0·5mg twice daily or matching placebo, starting within four hours before surgery and continuing for ten days. Healthcare providers, patients, data collectors, and adjudicators were blinded to treatment assignment. The co-primary outcomes were clinically important perioperative AF and MINS during 14 days of follow-up. This trial is registered at ClinicalTrials.gov (NCT03310125). Findings We enrolled 3209 patients between February 14, 2018, and June 27, 2023. Clinically important AF developed in 103 of 1608 (6·4%) patients assigned to colchicine, and 120 of 1601 (7·5%) patients assigned to placebo, hazard ratio (HR) 0·85 (95% confidence interval [CI] 0·65-1·10), absolute risk reduction (ARR) 1·1%, 95% CI -0·7-2·8, p=0.22. MINS occurred in 295 (18·3%) patients assigned to colchicine, and 325 (20·3%) patients assigned to placebo, HR 0·89 (95% CI 0·76-1·05), ARR 2·0%, 95% CI -0·8-4·7, p=0.16. Non-infectious diarrhoea was more common in the colchicine group, 134 (8·3%) versus 38 (2·4%) events, HR 3·64 (95% CI 2·54-5·22), but did not prolong median length of hospital stay and led to only one readmission.. Interpretation In patients undergoing major noncardiac thoracic surgery, administration of colchicine did not significantly reduce the incidence of the co-primary outcomes clinically important AF or MINS. While colchicine increased the risk of mostly benign non-infectious diarrhoea, there was an encouraging trend of fewer cardiovascular events with colchicine that requires further research.Canadian Institutes of Health Research, Accelerating Clinical Trials Consortium, and others

    Estimating the Poverty Impacts of Trade Liberalization

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    As a new round of World Trade Organization negotiations is being launched with greater emphasis on developing country participation, a body of literature is emerging which quantifies how international trade affects the poor in developing countries. This survey summarizes and classifies thirty-five studies from this literature into four methodological categories: cross-country regression, partial-equilibrium/cost-of-living analysis, general-equilibrium simulation, and micro-macro synthesis. These categories encompass a broad range of methodologies in current use. The continuum of approaches is bounded on one end by econometric analysis of household expenditure data, which is the traditional domain of poverty specialists, and sometimes labeled the “bottom-up” approach. On the other end of the continuum are computable general equilibrium models based on national accounts data, or what might be called the “top-down” approach. Another feature of several recent trade/poverty studies – and one of the primary conclusions to emerge from the October 2000 Conference on Poverty and the International Economy sponsored by Globkom and the World Bank – is recognition that factor markets are perhaps the most important linkage between trade and poverty, since households tend to be much more specialized in income than they are in consumption. Meanwhile, survey data on the income sources of developing-country households has become increasingly available. As a result, this survey gives particular emphasis to the means by which studies address factor market linkages between trade and poverty. The general conclusion is that any analysis of trade and poverty needs to be informed by both the bottom-up and top-down perspectives. Indeed, recent “two-step” micro-macro studies sequentially link these two types of frameworks, such that general equilibrium mechanisms are incorporated along with detailed household survey information. Another methodology similar in spirit and also increasingly used involves the incorporation of large numbers of surveyed households into a general-equilibrium simulation model. Although most of these studies have so far been limited to a single region, these approaches can be readily adapted for multi-region modeling so that trade-poverty comparisons can be made across countries within a consistent framework

    International Cross Section Estimates of Demand for Use in the GTAP Model

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    The making of projections often requires an economy-wide perspective, and the estimation of consumer demands at the international level. In this paper, an implicit, directly additive demand system (AIDADS) is estimated using cross-country data on consumer expenditures from the International Comparison Program (ICP), and then from Global Trade Analysis Project (GTAP) data. The two data sets are found to produce results that are quite consistent despite their differing origins, and the fact that the former is based on consumer goods that embody wholesale/retail margins, while margin demands are treated separately in GTAP. Given the similarity of the results, the estimation based on GTAP data is favored because it is readily matched to input-output based production and trade data, and provides valuable new information concerning how aggregate margin expenditures are related to per capita income
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