1,371 research outputs found

    Real-time evolution of an embedded controller for an autonomous helicopter

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    In this paper we evolve the parameters of a proportional, integral, and derivative (PID) controller for an unstable, complex and nonlinear system. The individuals of the applied genetic algorithm (GA) are evaluated on the actual system rather than on a simulation of it, thus avoiding the ldquoreality gaprdquo. This makes implicit a formal model identification for the implementation of a simulator. This also calls for the GA to be approached in an unusual way, where we need to consider new aspects not normally present in the usual situations using an unnaturally consistent simulator for fitness evaluation. Although elitism is used in the GAs, no monotonic increase in fitness is exhibited by the algorithm. Instead, we show that the GApsilas individuals converge towards more robust solutions

    Learning from difference and similarity: identities and relational reflexive learning

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    Within organizations there is reciprocal interplay between identity construction and learning. Processes of learning are enabled and constrained by identity practices; concomitantly, the possibilities for learning are shaped by the identity positions available to individuals. There is a dynamic between the impositions of organizations and people’s freedom to shape their identities and learning plays a crucial role in this. Our purpose in this special issue is to contribute to the understanding of the intersection of identity work and learning as a response to experiences of being different. Experiences of difference include moving into a new role, encountering a disjuncture with others while in a role or a difference in broader life which is reacted to as if it were a problem in an organizational setting. Being different produces a variety of challenges and the papers in this special issue trace how people cope with vulnerabilities, develop resilience and often collaborate in their learning. We focus on how people reflect on their own identity and learn and how, by learning together with people who have similar experiences, micro-communities can support, develop and enhance their insight and identity-positions

    An open platform for teaching and project based work at the undergraduate and postgraduate level.

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    Robots are a great tool for engaging and enthusing students when studying a range of topics. De Montfort University offers a wide range of courses from University access courses to Doctoral training. We use robots as tools to teach technical concepts across this wide and diverse range of learners. We have had great success using the Lego RCX and now NXT on the less demanding courses, and conversely with the MobileRobots Pioneer range for postgraduate and research projects. Although there is a distinct area in between these two where both these platforms meet our needs, neither is suitable for every aspect of our work. For this reason we have developed our own hardware and software platform to fulfil all of our needs. This paper describes the hardware platform and accompanying software and looks at two applications which made use of this system. Our platform presents a low-cost system that enables students to learn about electronics, embedded systems, communication, bus systems, high and low level programming, robot architectures, and control algorithms, all in individual stages using the same familiar hardware and software

    Arabidopsis DOF Transcription Factors Act Redundantly to Reduce CONSTANS Expression and Are Essential for a Photoperiodic Flowering Response

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    SummaryFlowering of Arabidopsis is induced by long summer days (LDs). The transcriptional regulator CONSTANS (CO) promotes flowering, and its transcription is increased under LDs. We systematically misexpressed transcription factors in companion cells and identified several DOF proteins that delay flowering by repressing CO transcription. Combining mutations in four of these, including CYCLING DOF FACTOR 2 (CDF2), caused photoperiod-insensitive early flowering by increasing CO mRNA levels. CO transcription is promoted to differing extents by GIGANTEA (GI) and the F-box protein FKF1. We show that GI stabilizes FKF1, thereby reducing CDF2 abundance and allowing transcription of CO. Despite the crucial function of GI in wild-type plants, introducing mutations in the four DOF-encoding genes into gi mutants restored the diurnal rhythm and light inducibility of CO. Thus, antagonism between GI and DOF transcription factors contributes to photoperiodic flowering by modulating an underlying diurnal rhythm in CO transcript levels

    Female Presidents of the "Royal College of Pathologists": Their Achievements and Contributions

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    The Royal College of Pathologists (RCPath) celebrates its Diamond Jubilee in 2022 since its opening by Her Majesty Queen Elizabeth II in 1962. One of the main remits of RCPath is the overseeing of the training of pathologists and scientists working in pathology's 17 different specialties within the United Kingdom and across the globe. During its 60 years, three female Presidents have been elected: Dame Barbara Clayton (1984-1987), Dr. Suzannah (Suzy) Lishman CBE (2014-2017), and Prof. Joanne (Jo) Martin (2017-2020). Whilst Clayton specialised in Chemical Pathology and its relevance to public health, both Lishman and Martin are diagnostic cellular histopathologists with differing areas of expertise. This article reviews the contributions of these three distinguished and inspirational female pathologists to Pathology ("the science behind the cure"), to healthcare, public health and education, medical research, and to teaching. It highlights their qualities as leaders and mentors for those not only in medicine but in other career settings

    Mitigating the effect of background noise in sound based helicopter control.

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    Our research focuses on the use of sound to enhance the control of an autonomous indoor helicopter - Flyper. One of the many challenging problems in this project is managing the uncertainty which is present in input data and the control actions; this paper focuses on managing the uncertainty in the input data. We present a fuzzy logic system which infers how much confidence should be placed on a control decision based on the data which was used to make that decision. The input data is a supervised and sound based position estimate of the flying robot. The output of the fuzzy inference system provides us with a confidence parameter used to attenuate the position control of the autonomous helicopter. We performed test flights with and without the fuzzy confidence parameter and with and without artificial disturbance in form of concurrent speech. We employed a motion tracker to capture the helicopter’s movement during all test flights. The analysis of the data collected shows encouraging results

    Patterns of BAP1 protein expression provide insights into prognostic significance and the biology of uveal melanoma

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    Uveal melanoma (UM) is a rare aggressive intraocular tumour with a propensity for liver metastases, occurring in ∼50% of patients. The tumour suppressor BAP1 is considered to be key in UM progression. Herein, we present the largest study to date investigating cellular expression patterns of BAP1 protein in 165 UMs, correlating these patterns to prognosis. Full clinical, histological, genetic, and follow‐up data were available for all patients. BAP1 gene sequencing was performed on a subset of 26 cases. An independent cohort of 14 UMs was examined for comparison. Loss of nuclear BAP1 (nBAP1) protein expression was observed in 54% (88/165) UMs. nBAP1 expression proved to be a significant independent prognostic parameter: it identified two subgroups within monosomy 3 (M3) UM, which are known to have a high risk of metastasis. Strikingly, nBAP1‐positiveM3 UMs were associated with prolonged survival compared to nBAP1‐negative M3 UMs (Log rank, p = 0.014). nBAP1 protein loss did not correlate with a BAP1 mutation in 23% (6/26) of the UMs analysed. Cytoplasmic BAP1 protein (cBAP1) expression was also observed in UM: although appearing ‘predominantly diffuse’ in most nBAP1‐negative UM, a distinct ‘focal perinuclear’ expression pattern – localized immediately adjacent to the cis Golgi – was seen in 31% (18/59). These tumours tended to carry loss‐of‐function BAP1 mutations. Our study demonstrates loss of nBAP1 expression to be the strongest prognostic marker in UM, confirming its importance in UM progression. Our data suggest that non‐genetic mechanisms account for nBAP1 loss in a small number of UMs. In addition, we describe a subset of nBAP1‐negative UM, in which BAP1 is sequestered in perinuclear bodies, most likely within Golgi, warranting further mechanistic investigation

    Adaptive-mutation compact genetic algorithm for dynamic environments

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    The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link

    Verification of a rigorous 2D model of rough surface scattering

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    A rigorous two-dimensional (2D) model of electromagnetic surface scatter has been developed, based on a boundary element method (BEM) established by Simonsen [1]. Simulated far-field scatter is compared to that measured from a laser scatterometer for a sinusoidal grating, with a mean difference of 3% of the peak intensity

    Getting back to work after injury: the UK Burden of Injury multicentre longitudinal study

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    Background Injuries to working age adults are common and place a considerable burden on health services accounting for more than 10% of GP sick notes and 14% of those claiming benefits because they are unable to work in the UK. General practitioners (GPs) currently assess fitness to work and provide care and referral to other services to facilitate return to work (RTW). Recent UK recommendations suggest replacing GP sickness certification with independent assessments of fitness to work after four weeks sick leave. The impact of a wide range of injuries on RTW and subsequent need for independent fitness to work assessments has not been well studied in the UK. The aim of this study was to quantify RTW and factors predicting RTW following a wide range of injuries. Methods We used a multicentre longitudinal study, set in four acute NHS Trusts in the UK which recruited emergency department (ED) attenders and hospital admissions for injury and included those aged 16–65years that were employed or self-employed before the injury. Participants were followed up by postal questionnaire at 1, 4 and 12 months post injury to measure health status (EQ-5D), recovery, use of health and social services, time off work in the preceding month and work problems amongst those who had RTW. Multivariable Poisson regression with a robust variance estimator was used to estimate relative risks for factors associated with RTW. Results One month after injury 35% of ED attenders had fully RTW. The self employed were more likely (RR 1.70, 95% CI 1.17 to 2.47 compared with employed) and the moderate/severely injured less likely to RTW (RR 0.48, 95% CI 0.32 to 0.72 compared with minor injuries). At four months, 83% of ED attenders had RTW and self employment and injury severity remained significant predictors of RTW (self employment RR 1.15, 95% CI 1.03 to 1.30; moderate/severe injury RR 0.79, 95% CI 0.68 to 0.92). At four months 57% of hospital admissions had RTW. Men were more likely than women to RTW (RR 1.94, 95% CI 1.34 to 2.82), whilst those injured at work (RR 0.49, 95% CI 0.27 to 0.87 compared with at home) and those living in deprived areas (most deprived tertile RR 0.59, 95% CI 0.40 to 0.85 and middle tertile RR 0.61, 95% CI 0.40 to 0.93) were less likely to RTW. Health status was significantly poorer at one and four months after injury than before the injury and was significantly poorer amongst those that had not RTW compared to those that had. Problems with pain control, undertaking usual activities, mobility and anxiety and depression were common and persisted in a considerable proportion of participants up to four months post injury. Conclusions Injuries have a large impact on time off work, including amongst those whose injuries did not warrant hospital admission. The majority of injured people would require an in-depth fitness for work assessment if recent UK recommendations are implemented. Many people will have on-going pain, mobility problems, anxiety and depression at the point of assessment and it is important that patients are encouraged to use primary care services to address these problems. A range of factors may be useful for identifying those at risk of a slower recovery and a delayed RTW so that appropriate interventions can be provided to this group
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