171 research outputs found
A SuperNEC implementation of model besed parameter estimation by interpolating the method of moments impedance matrix
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
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Optic Nerve Head Image Analysis for Glaucoma Progression Detection
Glaucoma is a leading cause of visual disability across the world and when diagnosed the glaucoma patient will spend the rest of their life receiving treatment in managed clinical care. In the glaucoma clinic, retinal and optic nerve head (ONH) imaging can be used to help the clinician to manage patient treatment appropriately. By providing high resolution images of the optic nerve head structures and identifying changes therein related to disease onset and progression, an objective measure can be obtained as to how well or badly treatment is preventing further disease damage. This thesis contributes to the field of glaucoma progression detection by the analysis of clinical imaging data using confocal scanning laser tomography (CSLT). Primarily it is an investigation of how best to appraise and optimise current algorithms which aim to detect these glaucomatous structural changes in the optic nerve head. This is done by addressing how the performance of these methods can be best assessed in the absence of a gold standard for glaucomatous structural progression.
Glaucoma expert assessment of photographs of the optic disc is the current clinical standard of assessing glaucomatous damage evident in the ONH. This is used in this thesis to act as a reference standard by which these algorithms can be compared. In addition, the statistical principles underpinning trend detection techniques are also investigated along with the performance of these techniques to detect trends in CSLT data in the presence of different types of measurement noise and image quality. A new computer model is developed and validated to simulate stable series of CSLT images, with realistic variability, which can be used to benchmark the false-positive rates of current and future progression algorithms. In conclusion, the main results reported in this thesis show that uncertainties involved in expert assessment of change in ONH photographs limits this as a reference standard for structural change in glaucoma. In addition, since stability in clinical datasets is uncertain, simulation using modelled series is shown to provide a new benchmark for comparing methods of progression detection
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
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
© 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
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Assessing the impact of a Carer Support Needs Assessment Tool (CSNAT) intervention in palliative home care: a stepped wedge cluster trial.
OBJECTIVES: To test the impact on family carers of a Carer Support Needs Assessment Tool (CSNAT) intervention to facilitate carer-led assessment and support during end of life care. METHOD: Mixed method, part-randomised, stepped wedge cluster trial with 6 palliative home care services comparing carers receiving the intervention with those receiving standard care. Postal survey with carers 4-5 months postbereavement measured adequacy of end of life support, current mental and physical health (Short Form 12 Health Survey SF-12), level of grief (Texas Revised Inventory of Grief, TRIG) and distress (Distress Thermometer, DT), place of death and carer satisfaction with place of death. RESULTS: Surveys were sent to 3260 (76%) carers of 4311 deceased patients; 681 (21%) were returned (N=333 control, N=348 intervention). Compared with controls, intervention carers had significantly lower levels of early grief, better psychological and physical health, were more likely to feel the place of death was right, and patients were more likely to die at home. However, differences were small and process measures showed low level of implementation, indicating differences may partially relate to increased awareness of carer issues rather than a direct impact of the intervention. CONCLUSIONS: Carers had better outcomes in the intervention condition, albeit modest. If this can be achieved through low level implementation and awareness raising of carers' needs from implementation activities, substantial impact should be possible if the CSNAT intervention can be fully implemented with a majority of carers. The study illustrates challenges of implementing and testing a complex intervention in real-life practice and of achieving comprehensive carer assessment and support in line with government recommendations
Vitamin D metabolites are associated with musculoskeletal injury in young adults: a prospective cohort study.
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
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 < 0.001). The peak SWS in the treated segment significantly decreased by 0.44 ± 0.13 (p < 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 < 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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