23,224 research outputs found

    Summertime ozone at Mount Washington: Meteorological controls at the highest peak in the northeast

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    This study examined the synoptic and regional-scale meteorological controls on summertime O3 at Mount Washington, the highest peak (1910 m) in the northeastern United States. Analysis of air mass transport to Mount Washington was conducted for the summers of 1998–2003 using backward trajectories. Distinct patterns in air mass history were revealed using this approach that helped explain extreme variations in O3 mixing ratios. Most enhanced (≄90th percentile) and depleted (≀10th percentile) O3 events were short-lived and spread out over the summer months. Enhanced O3 events at Mount Washington were generally associated with westerly transport, while depleted events corresponded to northwesterly transport. Periods of O3 greater than 80 ppbv during nighttime periods coincided with westerly (71%) and southwesterly (29%) transport. Periods of elevated O3 commonly occurred during regional warm sector flow or on the western edge of a surface anticyclone. Our analysis also identified a stratospheric contribution to a small percentage (∌5%) of extreme O3 events at the site, but more evidence is required to establish the significance of the contribution to background O3levels in this region

    A Multi-Robot Cooperation Framework for Sewing Personalized Stent Grafts

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    This paper presents a multi-robot system for manufacturing personalized medical stent grafts. The proposed system adopts a modular design, which includes: a (personalized) mandrel module, a bimanual sewing module, and a vision module. The mandrel module incorporates the personalized geometry of patients, while the bimanual sewing module adopts a learning-by-demonstration approach to transfer human hand-sewing skills to the robots. The human demonstrations were firstly observed by the vision module and then encoded using a statistical model to generate the reference motion trajectories. During autonomous robot sewing, the vision module plays the role of coordinating multi-robot collaboration. Experiment results show that the robots can adapt to generalized stent designs. The proposed system can also be used for other manipulation tasks, especially for flexible production of customized products and where bimanual or multi-robot cooperation is required.Comment: 10 pages, 12 figures, accepted by IEEE Transactions on Industrial Informatics, Key words: modularity, medical device customization, multi-robot system, robot learning, visual servoing, robot sewin

    A Multi-Robot Cooperation Framework for Sewing Personalized Stent Grafts

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    This paper presents a multi-robot system for manufacturing personalized medical stent grafts. The proposed system adopts a modular design, which includes: a (personalized) mandrel module, a bimanual sewing module, and a vision module. The mandrel module incorporates the personalized geometry of patients, while the bimanual sewing module adopts a learning-by-demonstration approach to transfer human hand-sewing skills to the robots. The human demonstrations were firstly observed by the vision module and then encoded using a statistical model to generate the reference motion trajectories. During autonomous robot sewing, the vision module plays the role of coordinating multi-robot collaboration. Experiment results show that the robots can adapt to generalized stent designs. The proposed system can also be used for other manipulation tasks, especially for flexible production of customized products and where bimanual or multi-robot cooperation is required.Comment: 10 pages, 12 figures, accepted by IEEE Transactions on Industrial Informatics, Key words: modularity, medical device customization, multi-robot system, robot learning, visual servoing, robot sewin

    The Labour Market Mobility of Polish Migrants: A Comparative Study of Three Regions in South Wales, UK

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    Since Polish migrants began entering the UK labour market in the post-accession period, there has been a significant amount of case study research focusing on the impact of this large migrant group on the UK economy. However, ten years after enlargement, there is still insufficient information regarding the labour market mobility of Polish migrants residing in the UK for the longer term. The available research on this topic is largely concentrated in urban settings such as London or Birmingham, and does not necessarily capture the same patterns of labour market mobility as in non-urban settings. Using qualitative data collected in three case study locations – urban, semi-urban and rural – in the South Wales region from 2008–2012, this article has two main aims. First, given the proximity of the case study locations, the article highlights the diversity of the Polish migrant characteristics through the samples used. Second, using trajectories created from the data, this article compares the variations among the labour market movements of the Polish migrants in each sample to determine what characteristics influence labour market ascent. Through this comparative trajectory analysis, the findings from this article point to the relative English language competency of migrants as the primary catalyst for progression in the Welsh labour market across all three case study regions. The secondary catalyst, which is intertwined with the first, is the composition of the migrants’ social networks, which enable, or in some cases disable, labour market progression. These findings have significant implications in the national and in the supranational policy sphere regarding the employment of migrants as well as their potential for cultural integration in the future
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