Adding Neural Network Controllers to Behavior Trees without Destroying Performance Guarantees

In this paper, we show how Behavior Trees that have performance guarantees, in terms of safety and goal convergence, can be extended with components that were designed using machine learning, without destroying those performance guarantees. Machine learning approaches such as reinforcement learning or learning from demonstration can be very appealing to AI designers that want efficient and realistic behaviors in their agents. However, those algorithms seldom provide guarantees for solving the given task in all different situations while keeping the agent safe. Instead, such guarantees are often easier to find for manually designed model based approaches. In this paper we exploit the modularity of Behavior trees to extend a given design with an efficient, but possibly unreliable, machine learning component in a way that preserves the guarantees. The approach is illustrated with an inverted pendulum example.Comment: Submitted to IEEE Transactions on Game

The Sat-Comms Game: teaching a complex subject for interdisciplinary audiences

This paper addresses general space education for interdisciplinary audiences. In particular, this paper considers education in the field of Satellite Telecommunications (Sat-Comms). The challenge in presenting the field of sat-comms for effective learning is two-fold. Firstly, this field is interdisciplinary, the disciplines are coupled, and it is complex. Secondly, the typical audiences for this subject often have diverse backgrounds. Hence, a suitable teaching strategy is required, so that all students can learn from a training session. Publicly available sat-comms training is largely engineering focused. This study could not find suitable training for the purpose of interdisciplinary sat-comms education. Hence, to address this absence in available training, the author has created a workshop, which provides sat-comms education to interdisciplinary audiences. The workshop was empirically developed from the author’s experience at Inmarsat and at the International Space University. The workshop uses elements from Constructivist, Behaviourism, Cognitive, Connectivism, and Experiential learning theories. Furthermore, it was designed to be taught in person and online. The Sat-Comms Game was first trialled in an online format in 2021. The workshop worked well in engaging the participants during the session. Additionally, feedback on the workshop was positive. Hence, this trial indicated that the workshop could function logistically and engage people pedagogically. The author intends to conduct further trials and corresponding assessment methods to gauge the pedagogic effectivenes

Famine in Zimbabwe, 1890-1960

A seminar paper on recorded famine history in Zimbabwe from the period 1890 to 1960

Health and wellbeing promotion strategies for ‘hard to reach’ older people in England: a mapping exercise.

The version of the article that has been accepted for publication. This version may include revisions resulting from peer review but may be subject to further editorial input by Cambridge University Press.Background: Older people from deprived areas, the oldest old and those from ethnic minorities engage less in health promotion interventions and related research, potentially generating inequities. Aim: To explore and map the extent to which such ‘hard to reach’ groups of older people, are the focus of local health and wellbeing strategies in England. Methods: Document analysis of current health and wellbeing promotion strategies in a purposive sample of 10 localities in England with high proportions of some or all of the three hard-to-reach groups. Documents were analysed using an interpretive approach. Findings: A total of 254 documents were retrieved and reviewed. Much of the content of the documents was descriptive and reported the implications for resources/services of population ageing rather than actual initiatives. All localities had an Older People’s Strategy. Strategies to counter deprivation included redistribution of winter fuel payments, income maximisation, debt reduction and social inclusion initiatives, a focus on older owner occupiers and recruitment of village ‘agents’ to counter rural deprivation. The needs of the oldest old were served by integrated services for older people, a community alarm service with total coverage of the 85+ population, and dietary advice. The needs of Black and Ethnic Minority (BME) older people were discussed in all localities and responses included community work with BME groups, attention to housing needs and monitoring of service use by BME older people. Three other themes that emerged were: use of telecare technologies; a challenge to the idea of ‘hard to reach’ groups; and outreach services to those at most risk. Conclusions: Document analysis revealed a range of policy statements that may indicate tailoring of policy and practice to local conditions, the salience of national priorities, some innovative local responses to policy challenges and even dissenting views that seek to redefine the policy problem.Peer reviewe

An inverse predictive model for the design of functional textiles

PhD ThesisCoated woven fabrics are used for large scale structures including airports and sports stadia. Manufacturers produce a range of fabrics from which a single fabric is selected by the structural engineer based on design criteria such as stiffness, weight, strength and formability. Designs must therefore utilise a fabric with properties which may not be optimal for that particular application. This thesis develops and tests a model that allows a bespoke coated woven fabric to be designed with specified mechanical properties such as tensile stiffness, Poison’s ratio and shear stiffness. A method is developed to ‘invert’ an existing predictive mechanistic ‘unit cell’ model using the derivatives of the equations defining the unit cell. The existing model is altered to enable the prediction of shear characteristics in addition to tensile properties by the inclusion of the coating using a finite element representation. The ‘inverse’ model is shown to accurately design a fabric for specific and attainable targets of Young’s modulus, Poisson’s ratio, and shear stiffness which have been derived using the predictive model for various fabric stress states. The effect of variability in fabric parameters on the tensile response of a fabric is considered using both Monte Carlo and FORM analysis. The sensitivity of the fabric response to biaxial loading is calculated using the direction cosines defined in the FORM methodology. The calculation of fabric sensitivity also enables a detailed investigation of the sensitivity of fabric stress-strain behaviour to variation in individual fabric parameters. A method is developed to design fabrics with mechanical properties which are robust to changes in manufacturing parameters by altering the geometry of the fabric. The model is validated by comparing the inverse model output to unit cell model input and also to biaxial test results. The inverse model shows excellent fidelity with results calculated using the unit cell model, but fails to adequately reproduce the actual fabric geometry when target stiffness values are based on biaxial test data. A method for the removal of yarns from fabrics and tensile testing of coated fabric yarn specimens is also developed. iii It is common practice to use a plane stress formulation to approximate the stress-strain response of a coated woven fabric. Comparison of the model output with biaxial test results necessitated the creation of a method for the calculation of fabric tensile stiffness at multiple stress states instead of a single set of elastic constants. This approach takes into account the complex nonlinear behaviour of architectural fabrics by considering the variation in stress-strain behaviour at different biaxial stress states. The final inverse model provides a novel tool for the design of coated woven fabric with prescribed mechanical responses at multiple stress states that is robust to variations in its constituent parameters, with scope for future application in textile architecture, medical textiles and industrial textiles

Four new stygobitic cirolanids (Crustacea: Isopoda) from the Caribbean: with remarks on intergeneric limits in some cirolanids

Four new stygobitic and troglomorphic cirolanids are described from various parts of the Caribbean. Cirolana (C.) troglexuma n. sp. is described from a cave on one of the Exuma Cays, Bahamas; two subgenera are recognized in g.Cirolana: sg. Cirolana including troglexuma as only presently know stygobitic species, and sg. Anopsilana equally well represented by subterranean and by epigean species. Haptolana bowmani n. sp. and H. belizana n. sp. inhabit caves of Yucatan and Belize, respectively; interestingly they are both abundantly different from the Cuban species of this stygobenthic genus, showing more similarity with the species from Somalia and W. Australia. Jamaicalana pleoscissa n.g. n. sp. was discovered in a cave from Jamaica; the new genus has affinities with Anopsilana and Bahalana, but a combination of characters -some of them highly original- renders definition of a new genus necessary. Bahalana mayana Bowman should be removed from that genus, whereas Dodecalana yagerae Carpenter is an interesting species of Bahalana

Enabling research in care homes : an evaluation of a national network of research ready care homes

© 2014 Davies et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise statedIn the UK care homes are one of the main providers of long term care for older people with dementia. Despite the recent increase in care home research, residents with dementia are often excluded from studies. Care home research networks have been recommended by the Ministerial Advisory Group on Dementia Research (MAGDR) as a way of increasing research opportunities for residents with dementia. This paper reports on an evaluation of the feasibility and early impact of an initiative to increase care home participation in researchPeer reviewe