170 research outputs found

    A SuperNEC implementation of model besed parameter estimation by interpolating the method of moments impedance matrix

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    SuperNEC is a method of moments (MoM) electromagnetic eld solver based on the Numerical Electromagnetics Code (NEC). Much of the simulation time can be attributed to the lling of the impedance matrix, which is performed at each frequency point of interest. Impedance matrix interpolation methods have been implemented in SuperNEC to reduce the computational time required to ll the impedance matrix [Z]. Elements in [Z] vary predictably over frequency and can be approximated by a second order polynomial. A second improved method is implemented where the dominant frequency variation term is removed prior to calculating the tting function. A method of determining the optimum sample range relative to simulation range and maximum interaction distance has been developed. Given the correct choice of sample range the mean error in the MoM solution is less than 10% over the frequency range and the input impedance can be reproduced with good agreement over a wide bandwith. Improvement in the simulation e ciency of 1.7 times can be expected if su cient frequency points are of interest to account for the computational time required to sample the matrix and determine tting function coe cients. This method has been applied to a dipole antenna, an LPDA and a horn antenna. To increase the simulation bandwidth and retain an acceptable level of accuracy, the bandwidth is split into multiple sub-bands

    Gifted techspectations: A report on information and communications technology usage and expectations Of Irish gifted and talented students for The Irish Centre For Talented Youth

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    Gifted Techspectations is the first of a series of reports based on research by the DCU Leadership, Innovation and Knowledge Research Centre (LInK) based in DCU Business School. With its roots in an Irish business school, it is no surprise that LInK’s mission is to strengthen the competitiveness, productivity, innovation and entrepreneurial capacity of the Irish economy. Ireland’s next generation transformation will be enabled by information and communication technologies (ICT) and digital participation by members of Irish society. As a university research centre we have an important role to play in supporting education, industry and government to accelerate this transformation. With support from DCU Business School, Enterprise Ireland’s Innovation Voucher Programme, DCU’s Learning Innovation Unit, Cambridge University Press and the Nominet Foundation amongst others, LInK has undertaken a wide variety of activities to accelerate digital participation. These include applied research projects, seminar programmes, workshops and occasional research papers. In the last twelve months, 22 seminars, 5 workshops, and two 3-week courses have been held and over 200 Irish businesses and schools have benefited from LInK-related digital participation activities. Influenced by the US ECAR and Pew Internet and American Life projects, these digital participation activities were brought together under the Techspectations initiative in June 2010. The objective of Techspectations is to create both a body of research and analysis on ICT usage and expectations by Irish society and an interface for Irish education, industry and government institutions

    Towards understanding how individuals with inflammatory bowel disease use contemporary social media platforms for health-related discourse

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    © 2020 With a growing prevalence of social media use worldwide where individuals share varying aspects of their lives, this paper focuses on how individuals with a chronic illness use these communications platforms to discuss their health. This paper aims to provide a qualitative approach to understanding the connection between the technical features offered by Facebook, Twitter and Instagram and the therapeutic affordances experienced. Semi structured interviews were carried out with 38 participants living with Inflammatory Bowel Disease who use Facebook, Twitter and/or Instagram for health-related support. Interview transcripts were analysed systematically to draw connections between platform features and therapeutic affordances. The interview data was thematically coded through an adapted SCENA Model to infer therapeutic affordances, while content analysis identified the technical features discussed. Our findings indicate that most participants (79%) use more than one social media platform for health-related discourse and that features on the platforms offer different therapeutic affordances. Facebook Groups’ privacy settings affording self-presentation as individuals feel comforted that other people cannot see what they post, while hashtags afford connectivity on Twitter and Instagram, but not on Facebook. This approach enabled the authors to identify similarities and differences between social media platforms and their technical features

    Vitamin D metabolites are associated with musculoskeletal injury in young adults: a prospective cohort study.

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    The relationship between vitamin D metabolites and lower body (pelvis and lower limb) overuse injury is unclear. In a prospective cohort study, we investigated the association between vitamin D metabolites and incidence of lower body overuse musculoskeletal and bone stress injury in young adults undergoing initial military training during all seasons. In 1637 men and 530 women (age, 22.6 ± 7.5 years; BMI, 24.0 ± 2.6 kg∙m−2; 94.3% white ethnicity), we measured serum 25-hydroxyvitamin D (25(OH)D) and 24,25-dihydroxyvitamin D (24,25(OH)2D) by high-performance liquid chromatography tandem mass spectrometry, and 1,25-dihydroxyvitamin D (1,25(OH)2D) by immunoassay during week 1 of training. We examined whether the relationship between 25(OH)D and 1,25(OH)2D:24,25(OH)2D ratio was associated with overuse injury. During 12 weeks training, 21.0% sustained ≥1 overuse musculoskeletal injury, and 5.6% sustained ≥1 bone stress injury. After controlling for sex, BMI, 2.4 km run time, smoking, bone injury history, and Army training course (Officer, standard, or Infantry), lower body overuse musculoskeletal injury incidence was higher for participants within the second lowest versus highest quartile of 24,25(OH)2D (OR: 1.62 [95%CI 1.13–2.32; P = 0.009]) and lowest versus highest cluster of 25(OH)D and 1,25(OH)2D:24,25(OH)2D (OR: 6.30 [95%CI 1.89–21.2; P = 0.003]). Lower body bone stress injury incidence was higher for participants within the lowest versus highest quartile of 24,25(OH)2D (OR: 4.02 [95%CI 1.82–8.87; P < 0.001]) and lowest versus highest cluster of 25(OH)D and 1,25(OH)2D:24,25(OH)2D (OR: 22.08 [95%CI 3.26–149.4; P = 0.001]), after controlling for the same covariates. Greater conversion of 25(OH)D to 24,25(OH)2D, relative to 1,25(OH)2D (i.e., low 1,25(OH)2D:24,25(OH)2D), and higher serum 24,25(OH)2D were associated with a lower incidence of lower body overuse musculoskeletal and bone stress injury. Serum 24,25(OH)2D may have a role in preventing overuse injury in young adults undertaking arduous physical training

    Angiography-based superficial wall strain of de novo stenotic coronary arteries:serial assessment of vessels treated with bioresorbable scaffold or drug-eluting stent

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    Objectives: This study sought to present an angiography-based computational model for serial assessment of superficial wall strain (SWS, dimensionless) of de-novo coronary stenoses treated with either bioresorbable scaffold (BRS) or drug-eluting stent (DES). Background: A novel method for SWS allows the assessment of the mechanical status of arteries in-vivo, which may help for predicting cardiovascular outcomes. Methods: Patients with arterial stenosis treated with BRS (n = 21) or DES (n = 21) were included from ABSORB Cohort B1 and AIDA trials. The SWS analyses were performed along with quantitative coronary angiography (QCA) at pre-PCI, post-PCI, and 5-year follow-up. Measurements of QCA and SWS parameters were quantified at the treated segment and adjacent 5-mm proximal and distal edges. Results: Before PCI, the peak SWS on the ‘to be treated’ segment (0.79 ± 0.36) was significantly higher than at both virtual edges (0.44 ± 0.14 and 0.45 ± 0.21; both p &lt; 0.001). The peak SWS in the treated segment significantly decreased by 0.44 ± 0.13 (p &lt; 0.001). The surface area of high SWS decreased from 69.97mm2 to 40.08mm2 (p = 0.002). The peak SWS in BRS group decreased to a similar extent (p = 0.775) from 0.81 ± 0.36 to 0.41 ± 0.14 (p &lt; 0.001), compared with DES group from 0.77 ± 0.39 to 0.47 ± 0.13 (p = 0.001). Relocation of high SWS to device edges was often observed in both groups after PCI (35 of 82 cases, 41.7 %). At follow-up of BRS, the peak SWS remained unchanged compared to post-PCI (0.40 ± 0.12 versus 0.36 ± 0.09, p = 0.319). Conclusion: Angiography-based SWS provided valuable information about the mechanical status of coronary arteries. Device implantation led to a significant decrease of SWS to a similar extent with either polymer-based scaffolds or permanent metallic stents.</p
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