2,005 research outputs found

    Sustainable Water Management in the Minerals Industry

    Get PDF

    Inferring eye movements on the basis of head and visual target position

    Get PDF
    The modern optical lens design process relies on ray-tracing that requires the geometry of the visual task to be simulated in order to derive the optical parameters. Such measurements must take into account distant, intermediate and near visual tasks. SOLA has developed a non-intrusive, low cost system which tracks eye movements during the reading process. This report analyses their procedure in order to determine the accuracy of the tracking system. It concludes that some assumptions in the existing algorithm are overly restrictive, while, overall, this is an effective tracking method. In addition, a Fourier analysis of the sampling rate demonstrates that 10 Hz is a sufficiently high rate to use, and that lossy compression is adequate for their needs

    Prediction of power generation from a wind farm

    Get PDF
    Wind farms produce a variable power output depending on the wind speed. For management of power networks and for bidding for the supply of power, the future power available needs to be predicted for time intervals ahead of a few minutes to about 24 hours. This project used data from a wind farm and three meteorological stations to determine methods and ability to predict wind speed. Analyses using regression, neural networks, and a Kalman filter were examined. Prediction using a combination of local wind measure-ments and meteorological data appears to give the best results

    Diamond drilling for core sampling

    Get PDF
    The drilling for, and recovery of core samples from the earth's crust, sometimes at distances of up to 3 km from the surface, is subject to many practical problems. One of these problems involves the jamming of core samples inside the recovery cylinder during drilling. There is a need to analyse the forces involved when the recovery cylinder is sliding over the core. Several simple mechanisms associated with naturally occurring variations in rock and soil structure were suggested as possible causes of jamming. The results suggest that the simplest mechanisms are not the cause of the problem, but combinations of these simple mechanisms might well be the cause. The results and discussion indicate some experiments that would be useful in a further study of the problem, and data from the drilling operations that should be kept for further analysis

    Modelling and optimal control of plate evaporators

    Get PDF
    Evaporators are an important stage in the extraction of sugar from sugar cane. A model of a simple evaporator is developed and then extended to multiple stage evaporation. An approximate solution and an iterative solution to the equations are developed. From the properties of these models a control strategy is developed

    Visible spatial contiguity of social information and reward affects social learning in brown capuchins (<i>Sapajus apella</i>) and children (<i>Homo sapiens</i>)

    Get PDF
    Animal social learning is typically studied experimentally by the presentation of artificial foraging tasks. Although productive, results are often variable even for the same species. We present and test the hypothesis that one cause of variation is that spatial distance between rewards and the means of reward release causes conflicts for participants’ attentional focus. We investigated whether spatial contiguity between a visible reward and the means of release would affect behavioral responses that evidence social learning, testing 21 brown capuchins (Sapajus apella), a much studied species with variant evidence for social learning, and 180 two- to four-year old human children (Homo sapiens), a benchmark species known for a strong social learning disposition. Participants were presented with a novel transparent apparatus where a reward was either proximal or distal to a demonstrated means of releasing it. A distal reward location decreased attention towards the location of the demonstration and impaired subsequent success in gaining rewards. Generally, the capuchins produced the alternative method to that demonstrated whereas children copied the method demonstrated, although a distal reward location reduced copying in younger children. We conclude that some design features in common social learning tasks may significantly degrade the evidence for social learning. We have demonstrated this for two different primates but suggest that it is a significant factor to control for in social learning research across all taxa

    War Rations British Homemaking

    Get PDF
    Marabeth Paddock explains how British homemakers are solving war-time nutrition problems with ingenuit

    Optimising the relationship of electricity spot price to real-time input data

    Get PDF
    Electrical power is paid for at a marginal price calculated by an optimisation to minimise the total cost of generation based on bids made by the power generation companies and consumer requirements. Generation companies are paid on the marginal rate (the level of the highest bid accepted) determined at their location. Similarly bulk power consumers are charged on the marginal price of supply at their location, which includes costs related to delivery to the user’s location

    Provenance of sedimentary rocks

    Get PDF
    Understanding the origins, or provenance, of a sedimentary deposit is an important aspect of geology. Sedimentary rocks are derived from the erosion of other rocks and thus provide important records of the geological environment at the time they were deposited. Some minerals found in sedimentary rocks, such as zircon particles, can be dated using uranium-lead techniques to trace the age of their parent rock thus providing useful information about the geological environment. Statistical and mathematical analyses that can assist in the analysis of the distribution of ages of the zircon crystals are examined. Methods of defining a difference between the distributions of ages found in rock samples are proposed, and demonstrated in the division of multiple rock samples into clusters of similar types. A test for the existence of a cluster is developed, and statistics for comparing different rock samples examined. Estimating an accurate age for the sedimentary deposit itself proves to be difficult unless prior distributions providing significant extra information are available

    The interaction of social and perceivable causal factors in shaping ‘over-imitation’

    Get PDF
    Over-imitation has become a well-documented phenomenon. However there is evidence that both social and visible, physically causal factors can influence the occurrence of over-imitation in children. Here we explore the interplay between these two factors, manipulating both task opacity and social information. Four- to 7-year-old children were given either a causally opaque or transparent box, before which they experienced either (1) a condition where they witnessed a taught, knowledgeable person demonstrate an inefficient method and an untaught model demonstrate a more efficient method; or (2) a baseline condition where they witnessed efficient and inefficient methods performed by two untaught models. Results showed that the level of imitation increased with greater task opacity and when children received social information about knowledgeability consequent on teaching, but only for 6- to 7-year-olds. The findings show that children are selectively attuned to both causal and social factors when learning new cultural knowledge
    • …
    corecore