Countable dense homogeneity and the Baire property

AbstractConditions are given that ensure that certain open subsets of countable dense homogeneous spaces are countable dense homogeneous. Also, results are given which pertain to the questions: Is every countable dense homogeneous metric space Baire? Is every one completely metrizable

Robustness, Weak Stability, and Stability in Distribution of Adaptive Filteringalgorithms Under Model Mismatch

This work is concerned with robustness, convergence, and stability of adaptive filtering (AF) type algorithms in the presence of model mismatch. The algorithms under consideration are recursive and have inherent multiscale structure. They can be considered as dynamic systems, in which the `state\u27 changes much more slowly than the perturbing noise. Beyond the existing results on adaptive algorithms, model mismatch significantly affects convergence properties of AF algorithms, raising issues of algorithm robustness. Weak convergence and weak stability (i.e., recurrence) under model mismatch are derived. Based on the limiting stochastic differential equations of suitably scaled iterates, stability in distribution is established. Then algorithms with decreasing step sizes and their convergence properties are examined. When input signals are large, identification bias due to model mismatch will become large and unacceptable. Methods for reducing such bias are introduced when the identified models are used in regulation problems

Stochastic Game Approach to Air Operations

A Command and Control (C2) problem for Military Air Operations is addressed. Specifically, we consider C2 problems for air vehicles against ground based targets and defensive systems. The problem is viewed as a stochastic game. In this paper, we restrict our attention to the C2 level where the problem may consist of a few UCAVs or aircraft (or possibly teams of vehicles); less than say, a half-dozen enemy SAMs; a few enemy assets (viewed as targets from our standpoint); and some enemy decoys (assumed to mimic SAM radar signatures). At this low level, some targets are mapped out and possible SAM sites that are unavoidably part of the situation are known. One may then employ a discrete stochastic game problem formulation to determine which of these SAMs should optimally be engaged (if any), and by what series of air vehicle operations. Since this is a game model, the optimal opponent strategy is also determined. We provide analysis, numerical implementation, and simulation for full state feedback and measurement feedback control within this C2 context

Testing the psychometric properties of Kidscreen-27 with Irish children of low socio-economic status

BACKGROUND: Kidscreen-27 was developed as part of a cross-cultural European Union-funded project to standardise the measurement of children’s health-related quality of life. Yet, research has reported mixed evidence for the hypothesised 5-factor model, and no confirmatory factor analysis (CFA) has been conducted on the instrument with children of low socio-economic status (SES) across Ireland (Northern and Republic). METHOD: The data for this study were collected as part of a clustered randomised controlled trial. A total of 663 (347 male, 315 female) 8–9-year-old children (M = 8.74, SD = .50) of low SES took part. A 5- and modified 7-factor CFA models were specified using the maximum likelihood estimation. A nested Chi-square difference test was conducted to compare the fit of the models. Internal consistency and floor and ceiling effects were also examined. RESULTS: CFA found that the hypothesised 5-factor model was an unacceptable fit. However, the modified 7-factor model was supported. A nested Chi-square difference test confirmed that the fit of the 7-factor model was significantly better than that of the 5-factor model. Internal consistency was unacceptable for just one scale. Ceiling effects were present in all but one of the factors. CONCLUSIONS: Future research should apply the 7-factor model with children of low socio-economic status. Such efforts would help monitor the health status of the population

Barriers and facilitators of physical activity in adolescents with intellectual disabilities: An analysis informed by the COM-B model

BACKGROUND: Adolescents with intellectual disabilities are insufficiently physically active. Where interventions have been developed and delivered, these have had limited effectiveness, and often lack a theoretical underpinning. AIM: Through application of the COM‐B model, our aim is to explore the factors influencing adolescent physical activity within schools. METHODS: A qualitative methodology, using focus groups with students who have mild/moderate intellectual disabilities, their parents'/carers' and teachers'. The COM‐B model provided the lens through which the data were collected and analysed. RESULTS: We identified of a range of individual, interpersonal, and environmental factors influencing physical activity, across all six COM‐B constructs, within the context of the ‘school‐system’. CONCLUSION: This is the first study to use the COM‐B model to explore school‐based physical activity behaviour, for adolescents with intellectual disabilities. Identification of such physical activity behavioural determinants can support the development of effective and sustainable interventions