8,866 research outputs found

    Tuning maps for setpoint changes and load disturbance upsets in a three capacity process under multivariable control

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    Tuning maps are an aid in the controller tuning process because they provide a convenient way for the plant operator to determine the consequences of adjusting different controller parameters. In this application the maps provide a graphical representation of the effect of varying the gains in the state feedback matrix on startup and load disturbance transients for a three capacity process. Nominally, the three tank system, represented in diagonal form, has a Proportional-Integral control on each loop. Cross coupling is then introduced between the loops by using non-zero off-diagonal proportional parameters. Changes in transient behavior due to setpoint and load changes are examined by varying the gains of the cross coupling terms

    The Role of Worker Flows in the Dynamics and Distribution of UK Unemployment

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    Unemployment varies substantially over time and across subgroups of the labour market. Worker flows among labour market states act as key determinants of this. We examine how the structure of unemployment across groups and its cyclical movements across time are shaped by changes in labour market flows. Using novel estimates of flow transition rates for the UK over the last 35 years, we decompose unemployment variation into parts accounted for by changes in rates of job loss, job finding and flows via non-participation. Close to two-thirds of the volatility of unemployment in the UK over this period can be traced to rises in rates of job loss that accompany recessions. The share of this inflow contribution has been broadly the same in each of the past three recessions. Decreased job-finding rates account for around one-quarter of unemployment cyclicality and the remaining variation can be attributed to flows via non-participation. Digging deeper into the structure of unemployment by gender, age and education, the flow-approach is shown to provide a richer understanding of the unemployment experiences across population subgroups.labour market, unemployment, worker flows

    Protostellar Feedback Processes and the Mass of the First Stars

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    We review theoretical models of Population III.1 star formation, focusing on the protostellar feedback processes that are expected to terminate accretion and thus set the mass of these stars. We discuss how dark matter annihilation may modify this standard feedback scenario. Then, under the assumption that dark matter annihilation is unimportant, we predict the mass of stars forming in 12 cosmological minihalos produced in independent numerical simulations. This allows us to make a simple estimate of the Pop III.1 initial mass function and how it may evolve with redshift.Comment: 6 pages, Proceedings of 'The First Stars and Galaxies: Challenges for the Next Decade", Austin, TX, March 8-11, 201

    Short Note: Report of mummified leopard seal carcass in the southern Dry Valleys, McMurdo Sound, Antarctica.

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    The wide spread occurrence of mummified seal and penguin carcasses tens of kilometres from the open ocean is an interesting phenomenon occurring in the Antarctic Dry Valleys. Mummified seal carcasses were first reported by Scott’s expedition in 1903 (Scott 1969), and live seals and seal carcasses have since been reported many kilometres from the nearest ice-free ocean. Seal carcasses found in the McMurdo Dry Valleys are predominantly crabeater seals (Lobodon carcinophaga (Hombron & Jacquinot)) with a smaller number of Weddell seals, (Leptonychotes weddellii (Lesson)), also reported. Here we present only the second published report of a leopard seal carcass from the McMurdo Dry Valleys

    The role of worker flows in the dynamics and distribution of UK unemployment

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    Unemployment varies substantially over time and across subgroups of the labour market. Worker flows among labour market states act as key determinants of this variation. We examine how the structure of unemployment across groups and its cyclical movements across time are shaped by changes in labour market flows. Using novel estimates of flow transition rates for the UK over the last 35 years, we decompose unemployment variation into parts accounted for by changes in rates of job loss, job finding and flows via non-participation. Close to two-thirds of the volatility of unemployment in the UK over this period can be traced to rises in rates of job loss that accompany recessions. The share of this inflow contribution has been broadly the same in each of the past three recessions. Decreased job-finding rates account for around one-quarter of unemployment cyclicality and the remaining variation can be attributed to flows via non-participation. Digging deeper into the structure of unemployment by gender, age and education, the flow-approach is shown to provide a richer understanding of the unemployment experiences across population subgroups. Key words: labour market ; unemployment ; worker flows JEL classification: E24 ; J6

    The Role of Worker Flows in the Dynamics and Distribution of UK Unemployment

    Get PDF
    Unemployment varies substantially over time and across subgroups of the labour market. Worker flows among labour market states act as key determinants of this variation. We examine how the structure of unemployment across groups and its cyclical movements across time are shaped by changes in labour market flows. Using novel estimates of flow transition rates for the UK over the last 35 years, we decompose unemployment variation into parts accounted for by changes in rates of job loss, job finding and flows via non-participation. Close to two-thirds of the volatility of unemployment in the UK over this period can be traced to rises in rates of job loss that accompany recessions. The share of this inflow contribution has been broadly the same in each of the past three recessions. Decreased jobfinding rates account for around one-quarter of unemployment cyclicality and the remaining variation can be attributed to flows via non-participation. Digging deeper into the structure of unemployment by gender, age and education, the flow-approach is shown to provide a richer understanding of the unemployment experiences across population subgroups.labour market, unemployment, worker flows

    Continuous and Reinforcement Learning Methods for First-Person Shooter Games

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    Machine learning is now widely studied as thebasis for artificial intelligence systems within computer games.Most existing work focuses on methods for learning staticexpert systems, typically emphasizing candidate selection. Thispaper extends this work by exploring the use of continuous andreinforcement learning techniques to develop fully-adaptivegame AI for first-person shooter bots. We begin by outlining aframework for learning static control models for tanks withinthe game BZFlag, then extend that framework using continuouslearning techniques that allow computer controlled tanks to adaptto the game style of other players, extending overall playability bythwarting attempts to infer the underlying AI. We further showhow reinforcement learning can be used to create bots that learnhow to play based solely through trial and error, providing gameengineers with a practical means to produce large numbers ofbots, each with individual intelligences and unique behaviours;all from a single initial AI model

    Some Modern Approaches to the History of the Crusades

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    Testing use of mitochondrial COI sequences for the identification and phylogenetic analysis of New Zealand caddisflies (Trichoptera)

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    We tested the hypothesis that cytochrome c oxidase subunit 1 (COI) sequences would successfully discriminate recognised species of New Zealand caddisflies. We further examined whether phylogenetic analyses, based on the COI locus, could recover currently recognised superfamilies and suborders. COI sequences were obtained from 105 individuals representing 61 species and all 16 families of Trichoptera known from New Zealand. No sequence sharing was observed between members of different species, and congeneric species showed from 2.3 to 19.5% divergence. Sequence divergence among members of a species was typically low (mean = 0.7%; range 0.0–8.5%), but two species showed intraspecific divergences in excess of 2%. Phylogenetic reconstructions based on COI were largely congruent with previous conclusions based on morphology, although the sequence data did not support placement of the purse-cased caddisflies (Hydroptilidae) within the uncased caddisflies, and, in particular, the Rhyacophiloidea. We conclude that sequence variation in the COI gene locus is an effective tool for the identification of New Zealand caddisfly species, and can provide preliminary phylogenetic inferences. Further research is needed to ascertain the significance of the few instances of high intra-specific divergence and to determine if any instances of sequence sharing will be detected with larger sample sizes
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