448 research outputs found

    A fast direct solver for a class of two-dimensional separable elliptic equations on the sphere

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    An efficient, direct, second-order solver for the discrete solution of two-dimensional separable elliptic equations on the sphere is presented. The method involves a Fourier transformation in longitude and a direct solution of the resulting coupled second-order finite difference equations in latitude. The solver is made efficient by vectorizing over longitudinal wavenumber and by using a vectorized fast Fourier transform routine. It is evaluated using a prescribed solution method and compared with a multigrid solver and the standard direct solver from FISHPAK

    Monitoring and analysing attendance in first year university mathematics tutorials

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    As part of an innovative tutorial structure introduced to a first year university mathematics subject, an attendance monitoring system was implemented. The system collected data that was used to investigate the relationship between student attendance and assessment performance which is reported here. The implementation of this system also assisted in the increase of student participation and engagement

    Consumer reactions to corporate social responsibility (CSR) in Thailand: the moderating effect of competitive positioning

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    Purpose – The purpose of this paper is to understand the business case for corporate social responsibility (CSR) in Thailand by focusing on the consumer-organisational relationship and test the conceptual framework of Du et al. (2007). Design/methodology/approach – A quantitative study was conducted using a mall intercept survey of 184 Thai mobile phone service provider consumers in Bangkok, Thailand. Findings – A CSR emphasised brand is more likely than non-CSR emphasised brands to accrue consumer CSR awareness, positive attitude to company motivations and beliefs in the CSR of that company. Although beliefs are associated with consumers’ greater identification and advocacy behaviours towards the CSR emphasised brand than the non-CSR emphasised brands, they are not associated with loyalty. Practical implications – The paper provides potential guidance for companies to more effectively position and communicate their CSR activities to create differential advantages. Originality/value – Findings of the study demonstrate some support for a business case for CSR in Thailand

    Urban regeneration : enabled by mobility centric architecture

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    Thesis (M. Arch.)--Massachusetts Institute of Technology, Dept. of Architecture, 2010.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Page 130 blank. Cataloged from student submitted PDF version of thesis.Includes bibliographical references (pages 129, 131).The primary goal of this thesis is to develop a new urban architectural prototype to reinvigorate the British New Town. New models of adaptable, sustainable, architecture and urban design are explored with the ultimate goal of enhancing livability through mobility within these established towns. Modernized mobility and information technology networks enmeshed into the current system of over-congested roads and under-utilized yet ubiquitous cycle pathway's, will engage and connect communities that are currently dissociated because of the expired components of original New Town design. The architectural focus will be on creating a networked system of enhanced mobility hubs at strategic locations within a town with the goal of shifting transportation behavior to revive/re-create community centers. The research and scope of this thesis will thus be on revitalizing the British New Town with a novel, sustainable and adaptable model of urban mobility.by Wayne Charles Higgins.M.Arch

    Identification of co-regulated transcripts affecting male body size in Drosophila

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    Factor analysis is an analytic approach that describes the covariation among a set of genes through the estimation of 'factors', which may be, for example, transcription factors, microRNAs (miRNAs), and so on, by which the genes are co-regulated. Factor analysis gives a direct mechanism by which to relate gene networks to complex traits. Using simulated data, we found that factor analysis clearly identifies the number and structure of factors and outperforms hierarchical cluster analysis. Noise genes, genes that are not correlated with any factor, can be distinguished even when factor structure is complex. Applied to body size in Drosophila simulans, an evolutionarily important complex trait, a factor was directly associated with body size

    Distribution Pattern Variability of Granular VRT Applicators

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    Granular applicators equipped with variable-rate technology (VRT) have gained popularity in recent years as a result of increased interest in variable-rate application. The purpose of this investigation was to characterize distribution patterns at varying rates for different granular applicators. Uniform-rate (UR) tests were conducted to assess the accuracy of variable-rate application from four granular applicators: two spinner-disc spreaders (A and B), and two pneumatic applicators (C and D). Pattern results indicated a consistent triangular pattern for spinner spreader B and consistent patterns for the pneumatic applicators (C and D). However, applicator D produced pattern variations at the center and right side. Simulated overlap analysis generated CVs \u3c 20% for applicators B and C. Applicator A performed well at the two lower rates (CVs \u3c 19%) but not at the highest rate (CV = 27%). Pattern unevenness for applicator D produced CVs between 25% and 34%. The spinner-disc spreaders over-applied, while the pneumatic applicators under-applied at the margins, suggesting an adjustment to the effective swath spacing or spinner-disc speed is needed to improve application accuracy. Further, overlap plots indicated pattern variability even when acceptable CVs were attained for applicators B and C. Therefore, it is recommended that CVs accompany simulated overlap pattern plots to ensure proper calibration of VRT equipment. Swath spacing analysis indicated that three of the four applicator spacings could be changed from the recommended value to improve application uniformity. Pattern comparisons showed that pattern shifts occurred for applicator A (P = 0.0092) with increasing application rate but not for applicators B, C, and D. These results demonstrate potential application errors with VRT and the need for proper calibration to maintain acceptable performance. Further, this investigation demonstrates the need for a VRT equipment testing standard

    Technical report series on global modeling and data assimilation. Volume 6: A multiyear assimilation with the GEOS-1 system: Overview and results

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    The Data Assimilation Office (DAO) at Goddard Space Flight Center has produced a multiyear global assimilated data set with version 1 of the Goddard Earth Observing System Data Assimilation System (GEOS-1 DAS). One of the main goals of this project, in addition to benchmarking the GEOS-1 system, was to produce a research quality data set suitable for the study of short-term climate variability. The output, which is global and gridded, includes all prognostic fields and a large number of diagnostic quantities such as precipitation, latent heating, and surface fluxes. Output is provided four times daily with selected quantities available eight times per day. Information about the observations input to the GEOS-1 DAS is provided in terms of maps of spatial coverage, bar graphs of data counts, and tables of all time periods with significant data gaps. The purpose of this document is to serve as a users' guide to NASA's first multiyear assimilated data set and to provide an early look at the quality of the output. Documentation is provided on all the data archives, including sample read programs and methods of data access. Extensive comparisons are made with the corresponding operational European Center for Medium-Range Weather Forecasts analyses, as well as various in situ and satellite observations. This document is also intended to alert users of the data about potential limitations of assimilated data, in general, and the GEOS-1 data, in particular. Results are presented for the period March 1985-February 1990
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