Influence of wear algorithm formulation on computational-experimental corroboration

Experimental wear testing is well-established as an important part of the TKR design process. Recently, in-silico models have proved their value to corroborate long-term in-vitro results on a much shorter timescale [1]. Both FE-based models & multi-body dynamics can be used to predict contact pressures, sliding distances and cross-shear (CS). The precise mechanisms of wear are not sufficiently understood to permit analytical calculations, and so empirical formulations are used to estimate wear depths & volumes.Most early simulations were based on a modified Archard/Lancaster formulation; more recently a number of alternative formulations for cross shear have been proposed; it is unclear which is the most robust or accurate for the widest range of activities. The aim of this study was to develop and corroborate a fast in-silico wear model, and use this to compare different wear formulations

Performance of the resurfaced hip. Part 1: the influence of the prosthesis size and positioning on the remodelling and fracture of the femoral neck

Hip resurfacing is an established treatment for osteoarthritis in young active patients. Failure modes include femoral neck fracture and prosthesis loosening, which may be associated with medium-term bone adaptation, including femoral neck narrowing and densification around the prosthesis stem.Finite element modelling was used to indicate the effects of prosthesis sizing and positioning on the bone remodelling and fracture strength under a range of normal and traumatic loads, with the aim of understanding these failure modes better.The simulations predicted increased superior femoral neck stress shielding in young patients with small prostheses, which required shortening of the femoral neck to give an acceptable implant–bone interface. However, with a larger prosthesis, natural femoral head centre recreation in the implanted state was possible; therefore stress shielding was restricted to the prosthesis interior, and its extent was less sensitive to prosthesis orientation. With valgus orientation, the implanted neck strength was, at worst, within 3 per cent of its intact strength.The study suggests that femoral neck narrowing may be linked to a reduction in the horizontal femoral offset, occurring if the prosthesis is excessively undersized. As such, hip resurfacing should aim to reproduce the natural femoral head centre, and, for valgus prosthesis orientation, to avoid femoral neck fracture

Tile Pattern KL-Divergence for Analysing and Evolving Game Levels

This paper provides a detailed investigation of using the Kullback-Leibler (KL) Divergence as a way to compare and analyse game-levels, and hence to use the measure as the objective function of an evolutionary algorithm to evolve new levels. We describe the benefits of its asymmetry for level analysis and demonstrate how (not surprisingly) the quality of the results depends on the features used. Here we use tile-patterns of various sizes as features. When using the measure for evolution-based level generation, we demonstrate that the choice of variation operator is critical in order to provide an efficient search process, and introduce a novel convolutional mutation operator to facilitate this. We compare the results with alternative generators, including evolving in the latent space of generative adversarial networks, and Wave Function Collapse. The results clearly show the proposed method to provide competitive performance, providing reasonable quality results with very fast training and reasonably fast generation.Comment: 8 pages plus references. Proceedings of GECCO 201

Achieving academic engagement? The landscape for educational technology support in two UK institutions

Drawing on results from a Universities and Colleges Information Systems Association (UCISA) 2008 survey of technology enhanced learning use in UK universities, this paper highlights support issues that impact on achieving academic engagement. It will crossreference factors that were identified by respondents to the survey as encouraging development or that act as barriers with how TEL is supported. These sector wide findings will then be reflected upon with reference to two UK universities that represent the traditional binary divide in type of university in the UK. Lack of time is identified as a primary barrier with staff development as the primary remedy.UCISA, JIS

Cow, farm, and herd management factors in the dry period associated with raised somatic cell counts in early lactation

This study investigated cow characteristics, farm facilities, and herd management strategies during the dry period to examine their joint influence on somatic cell counts (SCC) in early lactation. Data from 52 commercial dairy farms throughout England and Wales were collected over a 2-yr period. For the purpose of analysis, cows were separated into those housed for the dry period (6,419 cow-dry periods) and those at pasture (7,425 cow-dry periods). Bayesian multilevel models were specified with 2 response variables: ln SCC (continuous) and SCC >199,000 cells/mL (binary), both within 30 d of calving. Cow factors associated with an increased SCC after calving were parity, an SCC >199,000 cells/mL in the 60 d before drying off, increasing milk yield 0 to 30 d before drying off, and reduced DIM after calving at the time of SCC estimation. Herd management factors associated with an increased SCC after calving included procedures at drying off, aspects of bedding management, stocking density, and method of pasture grazing. Posterior predictions were used for model assessment, and these indicated that model fit was generally good. The research demonstrated that specific dry-period management strategies have an important influence on SCC in early lactation

A Longitudinal Perspective Regarding the Use of VLEs by Higher Education Institutions in the United Kingdom

The version uploaded is the final copy that was sent to the publishers.Between 2001 and 2005 UCISA and JISC conducted surveys into issues relating to the acquisition, use, management and support of Virtual Learning Environments (VLEs). A number of other studies provide information on these issues during this period. Together they provide a substantial body of evidence that allows an analysis of the factors that enhance or inhibit institutional take-up and support provision for VLEs within the UK higher education sector. There is clear evidence of increasing use of VLEs but not of widespread change in pedagogic practice. VLE management is increasingly centralised in all matters considered strategic, with dedicated devolvement occurring for a range of support activities. Differences in practice exist between old and new universities. There is in general negligible interest in standards or in institutional collaboration

Do drinking motives mediate the relationship between neighborhood characteristics and alcohol use among adolescents?

Funding: Funding for the Scottish Health Behaviour in School-aged Children was provided by NHS Scotland. This work was also supported by the 600th Anniversary Ph.D. Scholarship which was awarded to Gina Martin by the University of St Andrews.Adolescents not only vary in their alcohol use behavior but also in their motivations for drinking. Young people living in different neighborhoods may drink for different reasons. The aims of this study were to determine if neighborhood characteristics were associated with adolescent drinking motives, and whether drinking motives mediate the relationship between neighborhood context and regular alcohol use. Data from the Scottish Health Behaviours in School-aged Children 2010 survey of students in their 4th year of secondary school were used. The study included 1119 participants who had data on neighborhood characteristics and had used alcohol in the past year. Students were asked questions about the local area where they lived, their alcohol use, and their motives for drinking alcohol, based on the Drinking Motives Questionnaire Revised Short Form (DMQR-SF). Multilevel multivariable models and structural equation models were used in this study. Coping motives showed significant variation across neighborhoods. Structural equation models showed coping motives mediated the relationships between neighborhood deprivation, living in an accessible small-town, and neighborhood-level disorder with regular alcohol use. Public health policies that improve neighborhood conditions and develop adaptive strategies, aimed at improving alcohol-free methods for young people to cope better with life’s stresses, may be particularly effective in reducing inequalities in adolescent alcohol use if targeted at small towns and areas of increased deprivation.Publisher PDFPeer reviewe

Better defined geological and hazard models for Bellahouston Park, Glasgow : extension, Autumn 2003

Glasgow City Council (GCC) would like the key, south-central area of Bellahouston Park to be used for public events and wish to further constrain hazard areas related to old mineworkings. Previous studies and a borehole drilling programme have improved the geological and hazard model related to the workings of the Knightswood Gas and Pollock Stone coals (Rogers and Sowerbutts, 2000; Monaghan, Browne & Culshaw 2003). However a problematic area remained around a 1960’s borehole record ‘Pollock Borehole 13’ that contained a 1.1m void at 22.2m depth (–1.7m OD). The void was interpreted as being at the level of the Banton Rider Coal and the geology of the borehole did not fit well with surrounding boreholes (Monaghan, Browne & Culshaw 2003). The area where this void would be projected to crop out (hazard class D2) was in the centre of the part of the park with least hazard (no recorded mineworkings). Therefore, GCC wished to further resolve the area of hazard class D2 to adequately understand the hazards to public safety in this prime area for future activities. GCC commissioned the British Geological Survey (BGS) to undertake stratigraphical logging of three additional boreholes and to update the geological and hazard models for southern Bellahouston Park accordingly. Please refer to Monaghan, Browne & Culshaw (2003) along with this report

Better defined geological and hazard models for Bellahouston Park, Glasgow

Borehole records prove that the Knightswood Gas Coal (KDG) has been extensively worked in Bellahouston Park, Glasgow. In 2000, the British Geological Survey (BGS) undertook a commissioned research project for Glasgow City Council (GCC) to produce geological and hazard models related to abandoned mineworkings for Bellahouston Park (Rogers and Sowerbutts, 2000). The models identified some areas of the Park that have a thin drift cover and are crossed by the KDG outcrop*. These areas were classed as having the greatest likelihood of voids from mining of the KDG reaching the surface. Crown holes have previously developed within these areas. Other coal seams that crop out within Bellahouston Park did not appear to have been worked with the exception of the ?Banton Rider Coal in a small area beneath the Sports Centre and workings of the Pollock Stone Coal immediately to the east of the Park. Glasgow City Council would like the key, south-central area of the Park to be used for public events and need to constrain further the areas of greatest hazard immediately down-dip of the KDG outcrop, and also adjacent areas of least hazard on the up-dip side of the KDG outcrop. GCC commissioned BGS to devise a drilling programme of 13 boreholes, undertake stratigraphical logging of the cores during the drilling period, and subsequent revision of the geological and hazard models