77 research outputs found
A “Soft” Approach to Analysing Mobile Financial Services Sociotechnical Systems
Advances in mobile computing have presented a huge opportunity to provide Mobile Financial Services (MFS) to half of the world’s population who currently do not have access to financial services. However, cybersecurity concerns in the mobile computing ecosystem have slowed down the adoption of MFS. The adoption of MFS is further hampered by the lack of a clear understanding of the interaction between the complex infrastructures and human factors that exist in the ecosystem for Mobile Financial Services Socio-Technical Systems (MFSSTS). This paper presents the work in progress of investigating the problem of MFSSTS. It discusses the preliminary results and understanding obtained from using Human Factor approaches to build and analyse the model for MFSSTS
Overvoltage at motor terminals in SiC-based PWM drives
Key points in the development of More Electrical Aircraft (MEA) are currently DC power distribution in higher voltage levels (540 V) and the use of disruptive technology such as Wide BandGap (WBG) semiconductors in power inverters. Using WBG components (SiC and GaN) increases the power converter mass density. However, fast switching of WBG components (tens of kV/s) induces voltage transient overshoots due to parasitic elements within the inverter. In addition, propagation and reflection phenomena along the harness connected to this inverter, even for small lengths, cause a significant voltage overshoot across the loads. Such overvoltage in Adjustable Speed Drives (ASD: association of inverter, harness and motor) supplied by the new HVDC 540 V aeronautical network could be fatal for the Electrical Insulation System (EIS). This paper proposes a fast and accurate modeling methodology to predict transient overvoltage; it allows us to analyze the impact of SiC inverter technology on overvoltage at motor terminals
Investigations on Partial Discharges risk in aeronautical rotating machine fed by HVDC 540Vdc network
The voltage level aboard new aircraft generations has grown from 115V AC to 230V AC . This has given rise to a new HVDC +/- 270V instead of +270V. The Adjustable Speed Drives (ASD) aboard more electrical aircraft are currently fed by fast switching PWM IGBT converters which rise time and fall time are higher than 50ns. To improve the converters power density, the very fast Wide Bandgap semiconductor technologies (Silicon Carbide) are currently under evaluation; their switching rise time and fall time could be lower than 20ns. This paper, by using industrial ASD fed by 540Vdc, initially addresses an experimental investigations analysis of motor overvoltages according to: inverters technologies (IGBT and SiC), harness length and harness shielding. Then, investigations on the Partial Discharges Inception Voltage (PDIV) are carried out on primary components of Electrical Insulation System (EIS) type 1 at atmospheric and reduced pressures, according to several parameters: magnet wire (MW) diameter, MW grade, polyimide insulating paper thickness. The paper concludes with a discussion of the different results and thoughts about overvoltages and partial discharges challenges
Advanced analysis of transient overvoltage in electromechanical chain fed by SiC inverter
Key areas in the development of More Electrical Aircraft (MEA) are, currently, DC power distribution in higher voltage levels and the use of disruptive technology such as Wide BandGap (WBG) semiconductor. Using WBG components (SiC and GaN) increases the power converter mass density. However, fast switching of WBG components (tens of kV/µs) induces voltage transient overshoots due to parasitic coupling within the inverter. In addition, propagation and reflection phenomena along the harness, even for small lengths, cause voltage overshoots across the loads. Such overvoltage in an electromechanical chain (association of inverter, harness and motor) supplied by the new HVDC 540V aeronautical network could be fatal for the Electrical Insulation System (EIS). This paper proposes an accurate and fast model to predict overvoltage along a harness; it allows to analyze the impact of SiC inverter output voltage waveforms
Positron emission tomography imaging of coronary atherosclerosis
Inflammation has a central role in the progression of coronary atherosclerosis. Recent developments in cardiovascular imaging with the advent of hybrid positron emission tomography have provided a window into the molecular pathophysiology underlying coronary plaque inflammation. Using novel radiotracers targeted at specific cellular pathways, the potential exists to observe inflammation, apoptosis, cellular hypoxia, microcalcification and angiogenesis in vivo. Several clinical studies are now underway assessing the ability of this hybrid imaging modality to inform about atherosclerotic disease activity and the prediction of future cardiovascular risk. A better understanding of the molecular mechanisms governing coronary atherosclerosis may be the first step toward offering patients a more stratified, personalized approach to treatment
Paediatric patient safety and the need for aviation black box thinking to learn from and prevent medication errors
Since the publication of To Err Is Human: Building a Safer Health System in 1999, there has been much research conducted into the epidemiology, nature and causes of medication errors in children, from prescribing and supply to administration. It is reassuring to see growing evidence of improving medication safety in children; however, based on media reports, it can be seen that serious and fatal medication errors still occur. This critical opinion article examines the problem of medication errors in children and provides recommendations for research, training of healthcare professionals and a culture shift towards dealing with medication errors. There are three factors that we need to consider to unravel what is missing and why fatal medication errors still occur. (1) Who is involved and affected by the medication error? (2) What factors hinder staff and organisations from learning from mistakes? Does the fear of litigation and criminal charges deter healthcare professionals from voluntarily reporting medication errors? (3) What are the educational needs required to prevent medication errors? It is important to educate future healthcare professionals about medication errors and human factors to prevent these from happening. Further research is required to apply aviation’s ‘black box’ principles in healthcare to record and learn from near misses and errors to prevent future events. There is an urgent need for the black box investigations to be published and made public for the benefit of other organisations that may have similar potential risks for adverse events. International sharing of investigations and learning is also needed
Integrating a health-related-quality-of-life module within electronic health records: a comparative case study assessing value added
<p>Abstract</p> <p>Background</p> <p>Health information technology (HIT) applications that incorporate point-of-care use of health-related quality of life (HRQL) assessments are believed to promote patient-centered interactions between seriously ill patients and physicians. However, it is unclear how willing primary care providers are to use such HRQL HIT applications. The specific aim of this study was to explore factors that providers consider when assessing the value added of an HRQL application for their geriatric patients.</p> <p>Methods</p> <p>Three case studies were developed using the following data sources: baseline surveys with providers and staff, observations of staff and patients, audio recordings of patient-provider interactions, and semi-structured interviews with providers and staff.</p> <p>Results</p> <p>The primary factors providers considered when assessing value added were whether the HRQL information from the module was (1) duplicative of information gathered via other means during the encounter; (2) specific enough to be useful and/or acted upon, and; (3) useful for enough patients to warrant time spent reviewing it for all geriatric patients. Secondary considerations included level of integration of the HRQL and EHR, impact on nursing workflow, and patient reluctance to provide HRQL information.</p> <p>Conclusions</p> <p>Health-related quality of life modules within electronic health record systems offer the potential benefit of improving patient centeredness and quality of care. However, the modules must provide benefits that are substantial and prominent in order for physicians to decide that they are worthwhile and sustainable. Implications of this study for future research include the identification of perceived "costs" as well as a foundation for operationalizing the concept of "usefulness" in the context of such modules. Finally, developers of these modules may need to make their products customizable for practices to account for variation in EHR capabilities and practice workflows.</p
Job control mediates change in a work reorganization intervention for stress reduction.
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