Benchmarking the performance of controllers for power grid transient stability

As the energy transition transforms power grids across the globe, it poses several challenges regarding grid design and control. In particular, high levels of intermittent renewable generation complicate the task of continuously balancing power supply and demand, requiring sufficient control actions. Although there exist several proposals to control the grid, most of them have not demonstrated to be cost efficient in terms of optimal control theory. Here, we mathematically formulate an optimal centralized (therefore non-local) control problem for stable operation of power grids and determine the minimal amount of active power necessary to guarantee a stable service within the operational constraints, minimizing a suitable cost function at the same time. This optimal control can be used to benchmark control proposals and we demonstrate this benchmarking process by investigating the performance of three distributed controllers, two of which are fully decentralized, that have been recently studied in the physics and power systems engineering literature. Our results show that cost efficient controllers distribute the controlled response amongst all nodes in the power grid. Additionally, superior performance can be achieved by incorporating sufficient information about the disturbance causing the instability. Overall, our results can help design and benchmark secure and cost-efficient controllers

Optimal control of a commercial building's thermostatic load for off-peak demand response

This paper studies the optimal control of a commercial building's thermostatic load during off-peak hours as an ancillary service to the transmission system operator of a power grid. It provides an algorithmic framework which commercial buildings can implement to cost-effectively increase their electricity demand at night while they are unoccupied, instead of using standard inflexible setpoint control. Consequently, there is minimal or no impact on user comfort, while the building manager gains an additional income stream from providing the ancillary service, and can benefit further by pre-conditioning the building for later periods. The framework helps determine the amount of flexibility that should be offered for the service, and cost optimized profiles for electricity usage when delivering the service. Numerical results show that there can be an economic incentive to participate even if the payment rate for the ancillary service is less than the price of electricity.Comment: 20 pages, 12 figure

A probabilistic verification theorem for the finite horizon two-player zero-sum optimal switching game in continuous time

In this paper we study continuous-time two-player zero-sum optimal switching games on a finite horizon. Using the theory of doubly reflected BSDEs with interconnected barriers, we show that this game has a value and an equilibrium in the players' switching controls.Comment: 18 page

Associations of awareness of age-related change with emotional and physical well-being: a systematic review and meta-analysis

This is the final version. Available on open access from OUP via the DOI in this recordBACKGROUND AND OBJECTIVES: This systematic review aimed to synthesize and quantify the associations of awareness of age-related change (AARC) with emotional well-being, physical well-being, and cognitive functioning. RESEARCH DESIGN AND METHODS: We conducted a systematic review with a correlational random effects meta-analysis. We included quantitative studies, published from January 1, 2009 to October 3, 2018, exploring associations between AARC and one or more of the following outcomes: emotional well-being, physical well-being, and cognitive functioning. We assessed heterogeneity (I2) and publication bias. RESULTS: We included 12 studies in the review, 9 exploring the association between AARC and emotional well-being and 11 exploring the association between AARC and physical well-being. No study explored the association between AARC and cognitive functioning. Six articles were included in the meta-analysis. We found a moderate association between a higher level of AARC gains and better emotional well-being (r = .33; 95% CI 0.18, 0.47; p <.001; I2 = 76.01) and between a higher level of AARC losses and poorer emotional (r = -.31; 95% CI -0.38, -0.24; p < .001; I2 = 0.00) and physical well-being (r = -.38; 95% CI -0.51, -0.24; p < .001; I2 = 83.48). We found a negligible association between AARC gains and physical well-being (r = .08; 95% CI 0.02, 0.14; p < .122; I2 = 0.00). Studies were of medium to high methodological quality. DISCUSSION AND IMPLICATIONS: There is some indication that AARC gains and losses can play a role in emotional well-being and that AARC losses are associated with physical well-being. However, the number of included studies is limited and there was some indication of heterogeneity. PROSPERO REGISTRATION: CRD42018111472.University of Exeter College of Life and Environmental Sciences (School of Psychology)University of Exeter College of Medicine and Healt

Resilience in caregivers of people with mild-to-moderate dementia: findings from the IDEAL cohort

\ua9 2023, The Author(s). Objectives: A novel model of resilience was tested in caregivers of people with mild-to-moderate dementia and was extended to explore whether including self-efficacy, optimism, and self-esteem improved its predictive value. Design: Cross-sectional. Setting: Data from the IDEAL cohort were used. Participants: The study comprised 1222 caregivers of people with dementia. Measurements: A composite resilience score was calculated from five measures. Multivariable regressions were used to investigate factors associated with resilience. Results: Greater resilience was associated with being older, being male, and caregiving for older people with dementia. Greater resilience was also observed when people with dementia had fewer functional difficulties and/or fewer neuropsychiatric symptoms, there was a stronger dyadic relationship, and the caregiver had fewer social restrictions, less neuroticism, and greater perceived competence. Surprisingly, caregiver self-efficacy, optimism, and self-esteem were unrelated to resilience. Conclusion: Caregivers of people with mild-to-moderate dementia generally scored well for resilience. Resilience was associated with both the personal characteristics of caregivers and level of care need among people with dementia. Future work is needed to determine whether the caregivers in this cohort appeared resilient because the care recipients had relatively low care needs and consequently placed fewer demands on caregiver well-being than would be the case where dementia is more advanced

Methods and approaches for enhancing communication with people with moderate-to-severe dementia that can facilitate their inclusion in research and service evaluation: Findings from the IDEAL programme

This is the final version. Available on open access from SAGE Publications via the DOI in this recordOBJECTIVES: Dementia can affect language processing and production, making communication more difficult. This creates challenges for including the person's perspective in research and service evaluation. This study aims to identify methods, tools and approaches that could facilitate meaningful communication with people with moderate-to-severe dementia and support the inclusion of their perspectives. METHODS: This qualitative study was conducted as part of the IDEAL programme and involved in-depth, semi-structured interviews with 17 dementia research and/or care professionals with expertise in communication. Transcripts were analysed using framework analysis. FINDINGS: Three main themes each with sub-themes were identified: (1) Awareness, knowledge and experience; (2) Communication approach and (3) Personalization. A person-centred orientation based on getting to know the participant and developing a bi-directional exchange formed the fundamental context for effective communication. Building on this foundation, an approach using pictures, photographs or objects that are meaningful to the person and appropriate for that person's preferences and ability could help to facilitate conversations. The findings were integrated into a diagram illustrating how the topics covered by the themes interrelate to facilitate communication. CONCLUSIONS: Useful skills and approaches were identified to help researchers engage and work with people with moderate-to-severe dementia and ensure their perspective is included. These covered getting to know the participant, using a variety of tangible tools and interactional techniques and considering the environment and context of the conversation.Alzheimer's SocietyEconomic and Social Research Council (ESRC)National Institute for Health Research (NIHR

Are profiles of social, cultural, and economic capital related to living well with dementia? Longitudinal findings from the IDEAL cohort

Copyright © 2022 Rationale: Research exploring social, cultural, and economic capital among people with dementia is scarce. Objective: We describe levels of social, cultural, and economic capital in people with dementia at baseline and levels of social and cultural capital 12 and 24 months later. We identify groups of people with dementia having different combinations of capital and explore whether the identified groups differ in personal characteristics at baseline and in quality of life (QoL), satisfaction with life (SwL), and well-being over time. Method: Baseline, 12-months, and 24-months data from 1537 people with dementia (age, mean = 76.4 years; SD = 8.5; Alzheimer's Disease = 55.4%) enrolled in the IDEAL cohort were analyzed. Social (interactions with friends, civic participation, social participation, neighborhood trust, social network), cultural (education, cultural participation) and economic (annual income) capital, QoL, SwL, well-being, and personal characteristics were assessed. Results: Compared to people their age, people with dementia reported slightly lower frequency of interactions with friends, social networks and social support, civic and cultural participation, education, and annual income. However, social engagement, cultural participation, and annual income are low among British older adults. Latent profile analysis identified four groups that, based on their levels of social, cultural, and economic capital were named socially and economically privileged (18.0% of participants); financially secure (21.0% of participants); low capital (36.9% of participants); and very low capital (24.1% of participants). Latent growth curve models showed that over time QoL, SwL, and well-being remained largely stable for all groups. Compared to the low capital group, the socially and economically privileged and financially secure groups had higher QoL and well-being whereas the group with very low capital had poorer QoL, SwL, and well-being. Conclusions: New policies and efforts from the government, philanthropic foundations, the voluntary and primary care sectors are needed to address social, cultural, and economic disadvantage among people with dementia.Economic and Social Research Council (ESRC) and the National Institute for Health and Care Research (NIHR) through grant ES/L001853/2. Alzheimer's Society, grant number 348, AS-PR2-16-001

Methods and approaches for enhancing communication with people with moderate-to-severe dementia that can facilitate their inclusion in research and service evaluation findings from the IDEAL programme

YesObjectives Dementia can affect language processing and production, making communication more difficult. This creates challenges for including the person’s perspective in research and service evaluation. This study aims to identify methods, tools and approaches that could facilitate meaningful communication with people with moderate-to-severe dementia and support the inclusion of their perspectives. Methods This qualitative study was conducted as part of the IDEAL programme and involved in-depth, semi-structured interviews with 17 dementia research and/or care professionals with expertise in communication. Transcripts were analysed using framework analysis. Findings Three main themes each with sub-themes were identified: (1) Awareness, knowledge and experience; (2) Communication approach and (3) Personalization. A person-centred orientation based on getting to know the participant and developing a bi-directional exchange formed the fundamental context for effective communication. Building on this foundation, an approach using pictures, photographs or objects that are meaningful to the person and appropriate for that person’s preferences and ability could help to facilitate conversations. The findings were integrated into a diagram illustrating how the topics covered by the themes interrelate to facilitate communication. Conclusions Useful skills and approaches were identified to help researchers engage and work with people with moderate-to-severe dementia and ensure their perspective is included. These covered getting to know the participant, using a variety of tangible tools and interactional techniques and considering the environment and context of the conversation.ESRC, NIHR (ES/L001853/2); Alzheimer's Society (348, AS-PR2-16-001

The impact of auditory hallucinations on “living well” with dementia: Findings from the IDEAL programme

This is the final version. Available from Wiley via the DOI in this record.data availability statement: IDEAL data were deposited with the UK data archive in April 2020 and will be available to access from April 2023. Details of how the data can be accessed after that date can be found here: http:// reshare.ukdataservice.ac.uk/854293/Objective: To determine whether auditory hallucinations in community-dwelling people with dementia (PwD) living in the community impacted on quality of life (QoL), subjective wellbeing and life satisfaction. Design: Cross-sectional cohort study. Settings and participants: 1251 community-dwelling PwD and caregivers were included in this study. Measures: Neuropsychiatric Inventory Questionnaire completed by caregiver interview. Mean differences between the absence and presence of auditory hallucinations were compared to scores on three validated measures of living well: QoL in Alzheimer's disease scale (QoL-AD), World Health Organization-Five Well-being Index and Satisfaction with Life Scale. Analysis of covariance determined the confounding contributions of cognition via Mini-Mental State Examination, depression via Geriatric Depression Scale-10, caregiver stress via Relative Stress Scale and whether antipsychotic drugs were prescribed. Results: Auditory hallucinations were associated with lower scores for QoL (p < 0.001, η2 = 0.01), wellbeing (p < 0.001, η2 = 0.02) and life satisfaction (p < 0.001, η2 = 0.01). After controlling for background measures, which were potential confounds, the relationship between auditory hallucinations and QoL (p = 0.04, pη2 = 0.01) and wellbeing (p < 0.000, pη2 = 0.02) remained significant but there was no significant association with life satisfaction. Conclusion: Auditory hallucinations are associated with lower QoL and wellbeing in PwD living in the community. This has implications for targeted therapies in PwD with psychotic symptoms.Economic and Social Research Council (ESRC)Alzheimer's Societ