Search results
6,595 records were found.
This thesis presents an approach to generating intelligent behaviour for agents in computer game-like worlds. Designing and implementing such agents is a difficult task because they are required to act in real-time and respond immediately to unpredictable changes in their environment. Such requirements have traditionally caused problems for AI techniques. To enable agents to generate intelligent behaviour in real-time, complex worlds, research has been carried out into two areas of agent construction. The first of these areas is the method used by the agent to plan future behaviour. To allow an agent to make efficient use of its processing time, a planner is presented that behaves as an anytime algorithm. This anytime planner is a hierarchical task network planner which allows a planning agent to interrupt its planning process at any t...
The need of improvement of the bias rate of convergence of traditional nonparametric hazard rate estimators has been widely discussed in the literature. Initiated by recent developments in kernel density estimation we distinguish and extend three popular bias reduction methods to the hazard rate case. A usual problem of fixed kernel hazard rate estimates is their poor performance at endpoints. Noticing the automatic boundary adaptive property of the local linear smoother (Fan and Gijbels [13]) we adapt the method to the hazard rate case and we show that it results in estimators with bias at endpoints reduced to the level of interior bias. We then turn our attention to global bias problems. Utilizing the proposals of Hall and Marron [16] for estimation using location varying bandwidth as a means to improve the bias rate of convergence, ...
Tufted ducks were trained to dive to and from a respirometer box on a 1.7 m dive tank, so that measurements of respiratory gas exchange could be measured, along with time budget data. These data were combined with power cost estimates of diving to show that the optimal breathing model quantitatively predicted surface duration and the oxygen metabolised during foraging for the mean of all subject ducks but not for individual birds. Respirometry data also showed that both the oxygen and carbon dioxide stores were close to full adjustment after mean surface duration suggesting they have a similar influence on surface duration in tufted ducks, while pre-dive hyperventilation caused hypocapnia suggesting carbon dioxide is more often a limiting factor on dive duration. Oxygen uptake was not affected by hypercapnic exposure between dives and ...
With stereotypes of imperial complicity and idealistic fantasy firmly in place, tentative assumptions as to the motives of early missionaries often prove less than satisfactory. The need for new master narratives which move beyond the old paradigms of Western expansion and African victimization are being called for by scholars of both North and South; narratives which allow room for strong archival evidence of an egalitarian joint endeavor and African cultural vitality without avoiding the investment in imperialism practiced by colonial personnel. Based on extensive archival research this study advocates an alternative proposal; missionaries caught in the grinding of contradictory opposites. Alfred Robert Tucker, as a professional artist, captured this tug-of-war on canvas but similar dichotomies are found in his approach, as a bishop ...
The principle aims of this thesis were to determine the effect of lowering plasma fatty acids (FA) on muscle microvascular blood volume (MBV) at rest and during exercise, investigate whether near-infrared spectroscopy (NIRS) can be used to measure muscle MBV in the obese, develop the contrast enhanced ultrasound (CEU) method in our laboratory for measuring muscle MBV of the human forearm, and use CEU to measure the MBV response to an oral glucose tolerance test (OGTT). No differences were observed in exercise-induced increases in MBV or resting MBV between control and low FA conditions created by niacin ingestion in lean and obese individuals. NIRS was not suited to measure muscle MBV in participants with a thick subcutaneous adipose tissue layer. The CEU method was successfully developed to measure MBV in the human forearm. CEU reveal...
Microwave circuits in the millimetre wave region demand low loss, and low dispersion transmission lines. The work carried out in this thesis is on low loss transmission lines and filters, based on a square coaxial transmission line which is made only of metal, avoiding dielectric and radiation losses. The metal structure inside the square coaxial transmission line is supported by stubs, which provide the mechanical support for the centre conductor for the coaxial transmission lines and filters. The coaxial structure is made by stacking thick planar layers of material to suit microfabrication, providing the means to design high Q Microwave and RF passive devices, this transmission line structure is compact compared with a microstrip or a stripline, and gives better loss performance. Through this thesis, the way of optimising the square ...
Processes controlling the transport of dissolved-phase organic solutes through clay aquitards have been investigated. The study was centred upon a former UK industrial facility at which dissolved-phase aromatic solutes contaminated, and in areas penetrated, a discrete clay bed underlying the site. The lacustrine clay stratum (1-2 m thick) at 6 m bgs located in a sand aquifer was cored in 13 locations and intensively sampled with depth (primarily benzene, ethylbenzene, toluene and styrene). Two types of hydrocarbon invasion profiles were identified; (i) diffusion-based invasion and (ii) advection-dominated invasion. The latter has been shown from extensive physicochemical analysis of the clay cores in the laboratory to be primarily through connected “palaeo-root” holes. Root connectivity has been shown at various scales (serial sectioni...
Let \(G\) be a simple linear algebraic group over the algebraically closed field \(k\). Assume \(p\) = char \(k\) > 0 is good for \(G\) and that \(G\) is defined and split over the prime field \(\char{bbold10}{0x46}_p\). For a power \(q\) of \(p\), we write \(G(q)\) for the Chevalley group consisting of the \(\char{bbold10}{0x46}_q\)-rational points of \(G\). Let \(F : G \rightarrow G\) be the standard Frobenius morphism such that \(G^F\)= \(G(q)\). Let \(B\) be an \(F\)-stable Borel subgroup of \(G\); write \(U\) for the unipotent radical of \(B\) and \(\char{eufm10}{0x75}\) for its Lie algebra. We note that \(U\) and \(\char{eufm10}{0x75}\) are \(F\)-stable and that \(U(q)\) is a Sylow \(p\)-subgroup of \(G(q)\). We study the adjoint orbits of \(U\) and show that the conjugacy classes of \(U(q)\) are in correspondence with the \(F\)-...
Chapter 0 details the notation and terminology used. Chapter 1 introduces the usual linear algebra over GF2 of edge space E and its orthogonal subspaces Z (cycle space) and Z* (cut space). "Reduced vectors" are defined as elements of the quotient space E/Z*. Reduced vectors of edges give a simple way of characterising edges that are bridges (their reduced vector is null) or 2-edge cuts (their vectors are equal), and also of spanning trees (the edges outside the tree are a basis) and form to the best of my knowledge a new approach. They are also useful in later chapters to describe Tait colorings, as well as cycle double covers. Perhaps the most important property of E/Z* is the Unique graph theorem: unlike in E, a list of which reduced vectors are edges uniquely determines graph structure (if edge connectivity is high enough; that cove...
Rodgers’ evolutionary model of concept analysis was used to develop definitions of children’s nursing and their special needs, from which the inherent qualities of children’s nurses were extrapolated and tested in a variety of ways. Firstly selectors of children’s nursing students evaluated the suitability of six hypothetical candidates, in a self administered postal questionnaire. There was some agreement on the identified pre-requisite qualities. Secondly a content analysis of 25 job descriptions for newly qualified children’s nurses, using NUD*IST was undertaken, to determine English NHS Trusts’ expectations. Across the sample there was agreement on the role of the children’s nurse, confirming the definition derived from the concept analysis. There was less agreement between trusts in the manner in which these expectations were expr...
