Browsing by Author "Harris, J. T."
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Item Open Access Item Open Access A nonlinear transportation model: a step-by-step solution(College of Aeronautics, 1960-03) Harris, J. T.The model has linear restraints and a functional, to be maximised, consisting of linear first-order interactions of variables. General applications of the model are stated. It is shoran that a direct solution is not generally possible, but iterative procedures, analogous to the 'Transportation' technique are developed both for integer and non-integer non-negative variables. A Tableau procedure is given, with suitable checks, to enable a solution to be systematically obtained:, and finally a numerical example is treated.Item Open Access Production, employment and productivity in the United Kingdom, 1948-55(College of Aeronautics, 1956-10) Harris, J. T.Production movements are analysed statistically according to the contribution of changes in, productivity within industries and activities, employment, and the re-distribution of employment between industries and activities, both singly and in combination. When applied in turn to the Index of Gross Domestic Product and the index of Manufacturing Production for the period 1948-55, the main contributors to increased output are seen to be improved productivity and higher employment levels. The Index of Gross Domestic Product increased by 27% during the period, the main contributors accounting for 67% and 22% of the value respectively. In the case of Manufacturing industry they accounted for 57% and 32% respectively, of the 42% increase in output. Significantly, a11 of the increase in employment went into manufacturing industries. The movements for the individual broad groups of industries and activities contributing to the indices were very varied so that a relatively small section of the economy accounted for a large proportion of the overall increase in production and productivity.Item Open Access Statistical parameters in planning aero-engine production(College of Aeronautics, 1963-02) Atkinson, A. H.; Harris, J. T.This report considers the estimation of statistical parameters and their application to production planning in the aero-engine industry. A similar pattern of behaviour to that already recognised as existing in the airframe industry is found to operate, though there are indications of quantitative differences. The build-up time to the planned peak rate of production in a particular situation is found to be about eighteen months but with variation between firms. The reduction in operator performance time, which occurs with repetition during the build-up period and afterwards, is discovered to be present in machining as well as assembly, but to a lesser extent. The logarithmic function generally descriptive of such a tendency is found to fit the actual man-hour content values rather than the cumulative average ones. The relationship between the logistic of output and the logarithmic function is established and made use of to estimate labour requirements from the commencement of production onwards. In addition to the above consideration of production variables, examples are given of the use of engine performance ratings to estimate costs. Finally, because of the importance of planning to productivity, a typical production programme has been included.