30793 research outputs found
Sort by
Active Voltage Control and Demand Peak-Clipping Using Soft Actor-Critic Method
Get PDFThis study presents a proprietary Soft Actor-Critic (SAC) algorithm for power distribution network active voltage control and demand peak-clipping, including on-load-tap-changing and direct load control. Voltage violation and transformer loads, determine the system's state, while actions comprise transformer tap changing, heat pump setting temperature, and Vehicle-to-Grid at 30% demand flexibility and rewards are designed to prevent voltage violations and transformer overload. After testing with various load levels, the trained agent can optimally select actions and minimise violations, however the model will be tuned with different parameters and demand shift and energy storage are suggested to be added in future work
Measuring flow resistance in rough-bed rivers using flume and CFD approaches
No full textMeeting abstract presented at EGU General Assembly 2024, Vienna, Austria, 14-19 April 2024.Accurate predictions of river channel flow resistance are necessary for estimating flow depth and/or velocity, and so are needed for predicting sediment transport and flood risk, river restoration and in-channel engineering. Standard approaches typically predict resistance as a function of the channel bed grain size distribution (GSD). However, in rough-bed rivers that comprise much of the river network (i.e. rivers where flow depth is not much greater than channel roughness elements), the sediment GSD is not the main factor that controls the channel shape, and so GSD does not provide a good predictor of flow resistance. In these channels, predictions need to instead account for the influence of multiple scales and shapes of roughness, including boulders, sediment patches, exposed bedrock and irregular banks, but we do not yet have suitable methods for making these predictions.
We present initial results from flume and CFD modelling experiments that have been designed to identify how irregular river-beds affects the spatial pattern of form drag and determine overall flow resistance. Both experiments take advantage of high-resolution topographic data that has been collected from field locations using new survey techniques (terrestrial laser scanning and structure from motion photogrammetry). In the flume experiments, we used the data to create 1:10 scale 3D reproductions of three different river beds. For each bed we incrementally add sediment cover, boulders, and rough walls, and measured changes in channel topography. For each configuration we then measure how water depth varied across a range of discharges to evaluate bulk flow resistance. In the CFD experiments, we simulate a range of flows over the field topography to evaluate the spatial pattern of form drag across the bed. In subsequent experiments the topography will be manipulated to retain specific topographic scales, in order to assess how form drag changes. From both sets of experiments, we will identify which topographic (surface roughness) metrics best represent the effect of the differing river bed properties on bulk flow resistance, and hence offer most promise for improved predictive equations
Implementing teleophthalmology services to improve cost-effectiveness of the national eye care system
Get PDFData availability:
All data generated or analyzed during this study are included in this published article. The TreeAge model is available from the corresponding author on reasonable request.Summary:
What was known before:
Teleophthalmology represents an effective means for triaging patients; however, the cost-effectiveness of such services remains unexplored in the scientific literature.
What this study adds:
This research represents the first health economic evaluation of a nationwide teleophthalmology service, aiming to quantify potential economic savings, gains in Quality-Adjusted Life-Years (QALY), and reductions in waiting times.Background and purpose:
Optometrist-assisted and teleophthalmology-enabled referral pathway (OTRP) for community optometry referrals has the potential to improve the capacity and efficiency of eye care delivery systems through risk stratification and limiting the number of improved referrals. This study investigates the expected future costs and benefits of implementing OTRP under various possible organizational set-ups relevant to a Danish context.
Methods:
A decision-analytic model (decision tree) with a one-year time horizon was constructed to portray alternative future patient referral pathways for people examined in optometry stores for suspected ocular posterior segment eye disease. The main outcomes were total healthcare costs per patient, average waiting time from eye examination in store until the start of treatment or end of referral pathway, and quality-adjusted life-years (QALY) gained. The economic evaluation compares the general ophthalmologist referral pathway (GO-RP) with a potential reimbursement model for the optometrist-assisted teleophthalmology referral pathways (R-OTRP) and a procurement model for the optometrist-assisted teleophthalmology referral pathways (P-OTRP).
Results:
The cost per individual with suspected ocular posterior segment eye disease was estimated to be £116 for GO-RP and £75 and £94 for P-OTRP and R-OTRP respectively. The average waiting time for diagnosis or end of referral pathway was 25 weeks for GO-RP and 5.8 and 5.7 for P-OTPR and R-OTPR respectively. QALY gain was 0.15 for P-OTRP/R-OTRP compared to 0.06 for GO-RP.
Conclusion:
OTRP is effective in reducing unnecessary referrals and waiting times, increasing patients’ HRQoL, and decreasing the costs of diagnosing individuals with suspected ocular posterior segment eye disease.This investor-initiated study was financially supported by the optical company Specsavers/Louis Nielsen A/S
Chronotype and self-reported sleep quality: Effects on mental health and cognitive functions
Get PDFThis thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University LondonChronotype is a multidimensional construct underlying circadian rhythms (CRs) of varied mechanisms, including sleep-wake cycles, body temperature, and alertness/arousal levels. It exists on a spectrum from morning (MCs; peak circadian arousal in the morning) to evening chronotypes (ECs; peak circadian arousal in the evening), with most individuals falling in the middle, known as intermediate chronotypes (ICs). Evening chronotype (EC) has been linked with sleep-related disturbances and psychopathology-related personality traits. EC has also been associated with adverse mental, physical and cognitive health outcomes but the roles of sleep-related disturbances and/or psychopathology-related personality traits in this association needs to be clarified.
This thesis addressed two broad questions: i) Is chronotype linked to mental health and what is the role of sleep quality in this relationship? To address this question, two psychometric studies were conducted to probe the chronotype-mental health relationship while also quantifying sleep quality and psychopathology-related personality traits (neuroticism, schizotypy, impulsivity) in young non-clinical adults residing in India (N=313), the UK (N=213), or Germany (N=247). ii) Does chronobiological variables [i.e., chronotype, time of day (ToD), synchrony effect] influence neurocognitive functions? First, a systematic review of the existing studies addressing the effects of chronotype, ToD or synchrony effects on cognitive performance was conducted. This was followed by two empirical studies: a) a behavioural study (N=63; age range: 18-40 years) to examine the effect of chronobiological variables and/or sleep quality on verbal learning and memory (immediate recall, recognition, delayed recall), and b) a psychophysiology study (N=45; age range: 18-40 years) to examine the effects of chronobiological variables and/or sleep quality on prepulse inhibition (PPI) of the acoustic startle response (an operational measure of sensorimotor gating function).
The findings of the investigations conducted in three independent samples (India, the UK, Germany) showed no direct association between chronotype and mental health in young non-clinical populations. Instead, sleep quality fully mediated chronotype-mental health relationship in these populations. The findings of the systematic review indicated (i) no main effect of chronotype on any cognitive function in most studies, and (ii) a synchrony effect in MCs and/or ECs, mainly but not exclusively in attention, inhibition and memory, in approximately 45% of the studies involving adults aged 18-45 years, and in 80% of the studies involving older (50+ years) adults. The empirical studies conducted as part of this project showed no main effect of chronotype and showed a partial synchrony effect (only in MCs) on delayed recall (episodic memory) but not on PPI (sensorimotor gating) in healthy young adults, most of whom self-reported good sleep quality.
In conclusion, the findings show that chronotype does not directly affect mental health and may influence some cognitive functions in interaction with ToD. The findings provide strong support for the sleep hypothesis as a predisposing, precipitating, and perpetuating risk factor for poor mental health and reject the widely reported role of chronotype as an independent transdiagnostic risk factor for mental health problems. The findings also highlight the need for sleep-centred interventions in clinical practices and public health initiatives to improve mental health, and the importance of synchrony (chronotype x ToD) effects when assessing cognitive performance of older adults
Assemblages of Muslim Racialisation
Get PDFThis chapter presents a theoretical framework of assemblages to unpack how racialisation processes exist in colour-blind societies. The chapter argues that these societies are imagined to be colour-blind and “race” is assumed to be irrelevant. Nonetheless, “race” never really disappears in these societies, but rather becomes omnipresent. Based on this thesis and drawing on comparative ethnographic material from Copenhagen and Montreal, the chapter unpacks the processes of Muslim racialisation using the conceptual framework of assemblages.Open access to Chapter 1 of this monograph was made possible through funding from The Leverhulme Trust
Search for central exclusive production of top quark pairs in proton-proton collisions at √ = 13 TeV with tagged protons
Get PDFA version of the article is available at arXiv:2310.11231v2 [hep-ex] (https://arxiv.org/abs/2310.11231). Comments: Replaced with the published version. Added the journal reference and the DOI. All the figures and tables can be found at https://cms-results.web.cern.ch/cms-results/public-results/publications/TOP-21-007 (CMS Public Pages). Report number: CMS-TOP-21-007, TOTEM 2023-002, CERN-EP-2023-113. Journal reference: JHEP 06 (2024) 187. Submission history: From: The CMS Collaboration: [v1] Tue, 17 Oct 2023 13:03:19 UTC (1,237 KB); [v2] Sun, 14 Jul 2024 07:45:25 UTC (1,987 KB).A search for the central exclusive production of top quark-antiquark pairs (tt̅) is performed for the first time using proton-tagged events in proton-proton collisions at the LHC at a centre-of-mass energy of 13 TeV. The data correspond to an integrated luminosity of 29.4 fb⁻¹. The tt̅ decay products are reconstructed using the central CMS detector, while forward protons are measured in the CMS-TOTEM precision proton spectrometer. An observed (expected) upper bound on the production cross section of 0.59 (1.14) pb is set at 95% confidence level, for collisions of protons with fractional momentum losses between 2 and 20%.SCOAP³
Search for a third-generation leptoquark coupled to a τ lepton and a b quark through single, pair, and nonresonant production in proton-proton collisions at √ = 13 TeV
Get PDFA version of the article is available at arXiv:2308.07826v2 [hep-ex] (https://arxiv.org/abs/2308.07826). Comments: Replaced with the published version. Added the journal reference and the DOI. All the figures and tables can be found at https://cms-results.web.cern.ch/cms-results/public-results/publications/EXO-19-016 (CMS Public Pages). Report number: CMS-EXO-19-016, CERN-EP-2023-144. Journal reference: JHEP 05 (2024) 311. Submission history: From: The CMS Collaboration: [v1] Tue, 15 Aug 2023 15:10:35 UTC (696 KB); [v2] Wed, 5 Jun 2024 12:49:06 UTC (696 KB).A search is presented for a third-generation leptoquark (LQ) coupled exclusively to a τ lepton and a b quark. The search is based on proton-proton collision data at a center-of-mass energy of 13 TeV recorded with the CMS detector, corresponding to an integrated luminosity of 138 fb⁻¹. Events with τ leptons and a varying number of jets originating from b quarks are considered, targeting the single and pair production of LQs, as well as nonresonant t-channel LQ exchange. An excess is observed in the data with respect to the background expectation in the combined analysis of all search regions. For a benchmark LQ mass of 2 TeV and an LQ-b-τ coupling strength of 2.5, the excess reaches a local significance of up to 2.8 standard deviations. Upper limits at the 95% confidence level are placed on the LQ production cross section in the LQ mass range 0.5–2.3 TeV, and up to 3 TeV for t-channel LQ exchange. Leptoquarks are excluded below masses of 1.22–1.88 TeV for different LQ models and varying coupling strengths up to 2.5. The study of nonresonant ττ production through t-channel LQ exchange allows lower limits on the LQ mass of up to 2.3 TeV to be obtained.SCOAP³
Participatory presence–social connectedness through collaborative art practices
Get PDFIn a post-Covid context, the term presence has become the subject of renewed academic focus, amplified by mass phenomena such as Zoom fatigue and online classroom teaching. The prism of new materialism allows for a new reading of relationships between technology and human sensing, physical and virtual presence and copresence, with possible design implications: Current research in public health and social-environment discourse is interested in the effect of presence on well-being. As a theoretical framework, new materialism provides a lens that foregrounds complex relations between affect and technology, enabling us, through interventions like the KIMA: Colour participatory artwork, to interrogate the broad discourse on mediated presence and social connectivity. This paper provides an overview of the AHRC-funded research project, 'p_ART_icipate!', which is a collaborative investigation led by the University of Greenwich, CNWL NHS Foundation Trust, and Brunel University. This paper describes one of the case studies within the project, ‘KIMA Colour’, a collaboration with the art collective Analema Group, the National Gallery and the Royal National Institute of the Blind (RNIB). The case study explores the effect of collective cultural experiences and participatory art on a sense of social connectivity and copresence. In collaboration with RNIB and a group of visually impaired individuals, the team asked how we can design meaningful and accessible online interfaces that actively contribute to a sense of ‘participatory presence’. Findings suggest a possible link between the experience, presence and social connectedness. This research aims to contribute to our understanding of participatory art and to provide recommendations for accessibility and facilitation designc for participatory online interfaces.The project was funded by the AHRC early career research grant
Advancing Organizational Performance: A Strategic Framework to Multiscale Modeling and Simulation
Get PDFIn the modern, fast-moving, and technology-centric business world, the importance of service desks in swiftly and effectively addressing tech-related challenges cannot be overstated. The changing nature of work environments, particularly with the rise of remote and hybrid models post-pandemic, highlights the critical need for a simulation strategy that goes beyond individual departments to include the broader organizational context across various levels. Focusing on this need, we embarked on a project using Discrete Event Simulation (DES) to tackle the operational hurdles faced by the service desk of a leading UK-based telecommunications firm, marking the beginning of a larger initiative aimed at multiscale modeling and simulation (MMS). We have formulated a robust five-phase strategic framework to elevate and enhance organizational performance by applying a detailed DES analysis to refine the service desk operations. This framework examines the potential for targeted improvements within the service desk to have wider benefits, impacting everything from staff satisfaction and efficiency to the overall resilience of the organization
CitySEIRCast: an agent-based city digital twin for pandemic analysis and simulation
Get PDFData availability:
The datasets generated and analyzed during the current study are available from the corresponding author on reasonable request.Supplementary Information is available at: https://link.springer.com/article/10.1007/s40747-024-01683-x#Sec27 .The COVID-19 pandemic has dramatically highlighted the importance of developing simulation systems for quickly characterizing and providing spatio-temporal forecasts of infection spread dynamics that take specific accounts of the population and spatial heterogeneities that govern pathogen transmission in real-world communities. Developing such computational systems must also overcome the cold-start problem related to the inevitable scarce early data and extant knowledge regarding a novel pathogen’s transmissibility and virulence, while addressing changing population behavior and policy options as a pandemic evolves. Here, we describe how we have coupled advances in the construction of digital or virtual models of real-world cities with an agile, modular, agent-based model of viral transmission and data from navigation and social media interactions, to overcome these challenges in order to provide a new simulation tool, CitySEIRCast, that can model viral spread at the sub-national level. Our data pipelines and workflows are designed purposefully to be flexible and scalable so that we can implement the system on hybrid cloud/cluster systems and be agile enough to address different population settings and indeed, diseases. Our simulation results demonstrate that CitySEIRCast can provide the timely high resolution spatio-temporal epidemic predictions required for supporting situational awareness of the state of a pandemic as well as for facilitating assessments of vulnerable sub-populations and locations and evaluations of the impacts of implemented interventions, inclusive of the effects of population behavioral response to fluctuations in case incidence. This work arose in response to requests from county agencies to support their work on COVID-19 monitoring, risk assessment, and planning, and using the described workflows, we were able to provide uninterrupted bi-weekly simulations to guide their efforts for over a year from late 2021 to 2023. We discuss future work that can significantly improve the scalability and real-time application of this digital city-based epidemic modelling system, such that validated predictions and forecasts of the paths that may followed by a contagion both over time and space can be used to anticipate the spread dynamics, risky groups and regions, and options for responding effectively to a complex epidemic.This work was supported in part by Hillsborough County, Florida, under Grant BOCC No: 22-0680
Data sources:
Access Repository Dashboard
Do you manage Open Research Online? Become a CORE Member to access insider analytics, issue reports and manage access to outputs from your repository in the CORE Repository Dashboard! 👇