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Torque Curve Optimization of Ankle Push-Off in Walking Bipedal Robots Using Genetic Algorithm
Get PDFFrom MDPI via Jisc Publications RouterHistory: accepted 2021-05-11, pub-electronic 2021-05-14Publication status: PublishedFunder: the project of National Key R&D Program of China; Grant(s): 2018YFC2001300, 51675222Funder: National Natural Science Foundation of China; Grant(s): 91848204, 91948302Ankle push-off occurs when muscle–tendon units about the ankle joint generate a burst of positive power at the end of stance phase in human walking. Ankle push-off mainly contributes to both leg swing and center of mass (CoM) acceleration. Humans use the amount of ankle push-off to induce speed changes. Thus, this study focuses on determining the faster walking speed and the lowest energy efficiency of biped robots by using ankle push-off. The real-time-space trajectory method is used to provide reference positions for the hip and knee joints. The torque curve during ankle push-off, composed of three quintic polynomial curves, is applied to the ankle joint. With the walking distance and the mechanical cost of transport (MCOT) as the optimization goals, the genetic algorithm (GA) is used to obtain the optimal torque curve during ankle push-off. The results show that the biped robot achieved a maximum speed of 1.3 m/s, and the ankle push-off occurs at 41.27−48.34% of the gait cycle. The MCOT of the bipedal robot corresponding to the high economy gait is 0.70, and the walking speed is 0.54 m/s. This study may further prompt the design of the ankle joint and identify the important implications of ankle push-off for biped robots
Does integrated health and care in the community deliver its vision? A workforce perspective
Get PDFPurpose –The purpose of this paper is to explore and capture workforce perceptions, experiences and insights of the phenomena of integrated care (IC) in a community health and care NHS trust in England; including whether there are any associated factors that are enablers, barriers, benefits or challenges; and the level of workforce engagement in the process of integrated health and care.
Design/methodology/approach – A qualitative design based on an interpretivist research paradigm was used with a purposive sampling technique. Five in-depth semi-structured interviews were conducted with community nursing, social workers and allied health professionals. Colaizzi’s (1978) descriptive phenomenological seven-step method was applied to analyse data, with the emergence of 170 significant statements, 170 formulated meanings and 8 thematic clustering of themes to reveal 4 emergent themes and 1 fundamental structure capturing the essential aspects of the structure of the phenomenon IC.
Findings – This study revealed four interdependent emergent themes: (1) Insight of IC and collaboration: affording the opportunity for collaboration, shared goals, vision, dovetailing knowledge, skills and expertise. Professional aspirations of person-centred and strength-based care to improve outcomes. (2) Awareness of culture and professionalism: embracing inter-professional working whilst appreciating the fear of losing professional identity and values. Working relationships based on trust, respect and understanding of professional roles to improve outcomes. (3) Impact of workforce engagement: participants felt strongly about their differing engagement experience in terms of restructuring and redesigning services. (4) Impact of
organisational structure: information technology (IT) highlighted a barrier to IC as differing IT platforms prevent interoperability with one system to one patient. Shared positivity of IC, embracing new ways of working.
Originality/value – This study proposes considerations for future practice, policy and research from a local, national and global platform, highlighting the need for any IC strategy or policy to incorporate the uniqueness of the “voice of the workforce” as a key enabler to integration developments, only then can IC be a fully collaborative approach
Quantifying the effects of medium voltage–low voltage distribution network constraints and distributed energy resource reactive power capabilities on aggregators
Get PDFFrom Wiley via Jisc Publications RouterHistory: received 2020-08-25, rev-recd 2021-02-01, accepted 2021-02-10, pub-electronic 2021-03-01, pub-print 2021-07Article version: VoRPublication status: PublishedAbstract: Distributed energy resources (DER), such as, photovoltaic systems and batteries, are becoming common among households. Although the main objective is reducing electricity imports (bills), they could also provide system‐level services via an aggregator. However, the more DER provide services, the more important is ensuring that the corresponding operation does not result in network issues. To help DER aggregators understand the implications of network constraints, an AC optimal power flow‐based methodology is proposed to quantify the effects that three‐phase low voltage (LV) and medium voltage (MV) network constraints can have on the volume of services that can be provided for a given horizon, and the potential benefits from using DER reactive power capabilities. Using a convex multi‐period formulation that avoids binary variables for batteries and incorporates voltage‐dependent load models, the methodology maximizes DER exports (services) for service‐related periods and household self‐consumption for other periods (reducing bills). Different service periods are assessed to explore the extent of services throughout the day. Results using a realistic UK MV‐LV network with 2400+ households, show that aggregator services can be highly overestimated when neglecting MV‐LV network constraints, are influenced by voltage‐demand load characteristics, and that exploiting DER reactive power capabilities can significantly unlock further services
The impact of socio-demographic factors on the survival of cancer patients in Zimbabwe
Get PDFFrom Springer Nature via Jisc Publications RouterHistory: received 2021-02-02, accepted 2021-04-27, registration 2021-06-01, pub-electronic 2021-06-10, online 2021-06-10, collection 2021-12Publication status: PublishedAbstract: We provide a survival analysis of cancer patients in Zimbabwe. Our results show that young cancer patients have lower but not significant hazard rate compared to old cancer patients. Male cancer patients have lower but not significant hazard rate compared to female cancer patients. Race and marital status are significant risk factors for cancer patients in Zimbabwe
The effects of psychosocial stress on item, cued‐pair and emotional memory
Get PDFFrom Wiley via Jisc Publications RouterHistory: received 2020-10-01, rev-recd 2021-04-26, accepted 2021-05-14, pub-electronic 2021-06-14Article version: VoRPublication status: PublishedFunder: Biotechnology and Biological Sciences Research Council; Id: http://dx.doi.org/10.13039/501100000268Abstract: Physical stress, such as from the cold‐pressor test, has been robustly associated with altered memory retrieval, but it is less clear whether the same happens following psychosocial stress. Studies using psychosocial stressors report mixed effects on memory, leading to uncertainty about the common cognitive impact of both forms of stress. The current study uses a series of four carefully designed experiments, each differing by only a single critical factor to determine the effects of psychosocial stress on specific aspects of episodic memory. In three experiments, we induced psychosocial stress after participants encoded words, then assessed retrieval of those words after a prolonged delay. These experiments found no effect of post‐encoding stress on recognition of neutral words or cued recall of word‐pairs, but a small effect on recollection of semantically related words. There were, however, positive relationships within the stress group between measures of stress (cortisol in experiment 1 and self‐reported‐anxiety in experiment 3) and recollection of single word stimuli. In the fourth experiment, we found that psychosocial stress immediately before retrieval did not influence word recognition. Recollection, particularly for semantically related stimuli, may therefore be more susceptible to the effects of psychosocial stress, and future studies can assess how this relates to other forms of stress. Overall, our findings suggest that the effects of psychosocial stress on episodic memory may be more subtle than expected, warranting further exploration in larger studies
The impacts of the drop in staffing provision in the transition between the youth custody estate and young adult/adult estate
Get PDFThis article offers a critical view of the differences in staffing provision between the YCE and young adult/adult estate. The data outlines the issues associated with the cliff-edge of staffing training and provision for young adults which is seemingly an accepted aspect of the young adult/adult estate. The accounts of staff and young people demonstrates how their experiences of diminished resources through to the young adult/adult estate are insufficient to provide the level of support required. It is argued that there should be greater numbers of suitably trained prison officers within institutions holding young adults to work effectively with this distinct population
Turning turtle: scaling relationships and self-righting ability in Chelydra serpentina
Get PDFFrom The Royal Society via Jisc Publications RouterHistory: received 2021-01-26, accepted 2021-01-28, pub-electronic 2021-03-03, pub-print 2021-03-10Article version: VoRPublication status: PublishedFunder: Leverhulme Trust; Id: http://dx.doi.org/10.13039/501100000275; Grant(s): RPG-2019-104Testudines are susceptible to inversion and self-righting using their necks, limbs or both, to generate enough mechanical force to flip over. We investigated how shell morphology, neck length and self-righting biomechanics scale with body mass during ontogeny in Chelydra serpentina, which uses neck-powered self-righting. We found that younger turtles flipped over twice as fast as older individuals. A simple geometric model predicted the relationships of shell shape and self-righting time with body mass. Conversely, neck force, power output and kinetic energy increase with body mass at rates greater than predicted. These findings were correlated with relatively longer necks in younger turtles than would be predicted by geometric similarity. Therefore, younger turtles self-right with lower biomechanical costs than predicted by simple scaling theory. Considering younger turtles are more prone to inverting and their shells offer less protection, faster and less costly self-righting would be advantageous in overcoming the detriments of inversion
Becoming an Urban Cycling Space
No full textPeter Cox shows how the rapid transformations of many city spaces during the covid-19 pandemic has dramatically altered both perceptions of the spaces in which cyclists ride the city and the possibilities of becoming an urban cyclist. This chapter first looks back in a wider historic context to show the double process of cyclists adapting to existing European cities and how, in turn, cyclists’ presence has changed the cities themselves. It then examines some of the adaptations produced in response to the pandemic and the ways in which this has made cities appear different spaces for cycling. Finally, it examines some of the emergent policy frameworks produced during this time and their implications for future relations between cyclists and other forms of urban mobility
A study of a nonlocal problem with Robin boundary conditions arising from technology
Get PDFFrom Wiley via Jisc Publications RouterHistory: received 2020-08-03, rev-recd 2021-02-18, accepted 2021-02-22, pub-electronic 2021-05-04Article version: VoRPublication status: PublishedIn the current work, we study a nonlocal parabolic problem with Robin boundary conditions. The problem arises from the study of an idealized electrically actuated MEMS (micro‐electro‐mechanical system) device, when the ends of the device are attached or pinned to a cantilever. Initially, the steady‐state problem is investigated estimates of the pull‐in voltage are derived. In particular, a Pohožaev's type identity is also obtained, which then facilitates the derivation of an estimate of the pull‐in voltage for radially symmetric N‐dimensional domains. Next a detailed study of the time‐dependent problem is delivered and global‐in‐time as well as quenching results are obtained for generic and radially symmetric domains. The current work closes with a numerical investigation of the presented nonlocal model via an adaptive numerical method. Various numerical experiments are presented, verifying the previously derived analytical results as well as providing new insights on the qualitative behavior of the studied nonlocal model
The social history of a medieval fish weir, c. 600-2020
Get PDFThis is an Accepted Manuscript of an article published by Taylor & Francis in Social History on 27 October 2021, available online: https://doi.org/10.1080/03071022.2021.1967637This paper presents the longue durée social history of a medieval fish weir. It reveals the significant role of fishing and fish weirs in the construction and reconstruction of social structures and cultural identities. It focuses on an enigmatic annual ceremony – the construction of the Horngarth or Penny Hedge at Whitby, North Yorkshire. It begins by arguing that this descends from the construction of a medieval intertidal fish weir. It then explores the possible social and cultural contexts in which it originated and the social and cultural circumstances that perpetuated its construction to the sixteenth century. It proceeds to consider the social and cultural changes that undermined its original function and transformed its significance in the sixteenth, seventeenth, and eighteenth centuries, and how an invented tradition about it became important to the local identity and national reputation of the town
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