12,260 research outputs found

    A simple wool marketing simulation model : a thesis presented in partial fulfillment of the requirements for the degree of Master of Agricultural Science at Massey University

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    The New Zealand Wool Marketing Study Group was set up in December, 1964 to investigate and report on all relevant aspects of wool marketing. The terms of reference of the Wool Marketing Study Group included the requirement that they should examine methods of containing wool price fluctuations whilst retaining the existing auction system as the basic method for the disposal of wool. The present study, supported in part by the Wool Marketing Study Group, examines what the effect would have been if alternative Wool Commission floor and ceiling price policies had been in force at New Zealand wool auctions for the historical period 1952/53 through 1965/66. [From Introduction

    Philosophy of Technology in the Americas in the Last Twenty-Five Years

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    This article summarizes and analyzes some of the most important contributions to the voluminous literature in philosophy of technology that has been produced during the past twenty-five years in North, Central, and South America. (Major focus is on North America.) The survey emphasizes the variety of standards the authors have attempted to measure up to, and ends with a plea that, whatever the standard invoked, an overarching standard ought to be to contribute to the solution of real-world problems of technological society

    Note on reflection and transmission coefficients for converging-diverging ducts

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    Simple formulas for calculating acoustic reflection and transmission coefficients for converging-diverging ducts are derived; they extend the method of Cho and Ingard to arbitrary, slowly varying ducts. These formulas involve two parameters. The first is a function of duct shape and the second is the ratio of the duct radius downstream of the throat to that upstream of the throat to the upstream of the throat. An extension of the method to include mean flow is made for symmetric ducts

    Asymptotic analysis of corona discharge from thin electrodes

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    The steady discharge of a high-voltage corona is analyzed as a singular perturbation problem. The small parameter is the ratio of the length of the ionization region to the total gap length. By this method, current versus voltage characteristics can be calculated analytically

    Universal power law behaviors in genomic sequences and evolutionary models

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    We study the length distribution of a particular class of DNA sequences known as 5'UTR exons. These exons belong to the messanger RNA of protein coding genes, but they are not coding (they are located upstream of the coding portion of the mRNA) and are thus less constrained from an evolutionary point of view. We show that both in mouse and in human these exons show a very clean power law decay in their length distribution and suggest a simple evolutionary model which may explain this finding. We conjecture that this power law behaviour could indeed be a general feature of higher eukaryotes.Comment: 15 pages, 3 figure

    Fast Filtering and Smoothing for Multivariate State Space Models

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    This paper gives a new approach to diffuse filtering and smoothing for multivariate state space models. The standard approach treats the observations as vectors while our approach treats each element of the observational vector individually. This strategy leads to computationally efficient methods for multivariate filtering and smoothing. Also, the treatment of the diffuse initial state vector in multivariate models is much simpler than existing methods. The paper presents details of relevant algorithms for filtering, prediction and smoothing. Proofs are provided. Three examples of multivariate models in statistics and economics are presented for which the new approach is particularly relevant.Diffuse initialisation;Kalman filter;multivariate models;smoothing;state space;time series

    Evaluation of the KA24 (Knowledge Access 24) service for health- and social-care staff in London and the south-east of England. Part 2: qualitative

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    AIMS AND OBJECTIVES: The aim of this two-part paper is to identify the main transferable lessons learned from both the quantitative and qualitative evaluations of the KA24 (Knowledge Access 24) service of online databases and selected full text journals for health and social care staff in London and the South-East of England. The objectives of the qualitative evaluation were to assess the enablers and barriers to usage, and to assess the impact of the service on patient care. METHODS: Telephone interviews (n=65) and a questionnaire survey (n=296) were conducted with various types of user, in various Trust settings. Some non-users were also contacted. Selection of interviewees and questionnaire recipients was not random, and aimed to cover all groups of users representatively. RESULTS: Results show that policy goals were being delivered, with indications of changes to clinical practice, and improved clinical governance. Promotion, training and support needs to be extensive, and tailored to needs, but users are not always aware they need training. The sharing of passwords cast doubts on the reliability of some usage data. CONCLUSIONS: Digital health library services, delivered at the point of care, are changing the way some clinicians practise. A combination of qualitative and quantitative evaluation methods are needed to assess digital library services

    Review: Adapting scalar turbulence closure models for rotation and curvature

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    Scalar, eddy viscosity models are widely used for predicting engineering turbulent flows. System rotation, or streamline curvature, can enhance or reduce the intensity of turbulence. Methods to incorporate the effects of rotation and streamline curvature consist of introducing parametric variation of model coefficients, such that either the growth rate of turbulent energy is altered; or such that the equilibrium solution bifurcates from healthy to decaying solution branches. For general use, parameters must be developed in coordinate invariant forms. Effects of rotation and of curvature can be unified by introducing the convective derivative of the rate of strain eigenvectors as their measure
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