Hybrid index maintenance for contiguous inverted lists     

Stefan Büttcher  Charles L. A. Clarke 《Information Retrieval》2008,11(3):175-207

Index maintenance strategies employed by dynamic text retrieval systems based on inverted files can be divided into two categories: merge-based and in-place update strategies. Within each category, individual update policies can be distinguished based on whether they store their on-disk posting lists in a contiguous or in a discontiguous fashion. Contiguous inverted lists, in general, lead to higher query performance, by minimizing the disk seek overhead at query time, while discontiguous inverted lists lead to higher update performance, requiring less effort during index maintenance operations. In this paper, we focus on retrieval systems with high query load, where the on-disk posting lists have to be stored in a contiguous fashion at all times. We discuss a combination of re-merge and in-place index update, called Hybrid Immediate Merge. The method performs strictly better than the re-merge baseline policy used in our experiments, as it leads to the same query performance, but substantially better update performance. The actual time savings achievable depend on the size of the text collection being indexed; a larger collection results in greater savings. In our experiments, variations of Hybrid Immediate Merge were able to reduce the total index update overhead by up to 73% compared to the re-merge baseline.

Stefan BüttcherEmail:

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How can the inspection process enhance improvement in special schools?     

Judy Sebba  John Clarke  Brian Emery 《欧洲特需教育杂志》2013,28(1):82-94

Abstract

The new system for the inspection of special schools was introduced in England in September 1994, using common criteria as those used for mainstream schools. One of the main purposes of inspection stated by the Office for Standards in Education (OFSTED) is school improvement. This paper presents the perceptions of headteachers of the inspection process arising from the first inspections carried out during September‐December 1994. The evidence base used on these inspections is also considered. These data are used to suggest that school improvement can be enhanced by the inspection process under certain conditions. A preliminary exploration of these conditions is provided in the paper. Implications for the school inspection process, school self‐review and future research questions are identified.  相似文献   

DR. WHITE'S PATENT ELIXIR FOR PARENTS     

Alison Clarke‐Stewart 《Review of Education, Pedagogy & Cultural Studies》2013,35(2):101-111

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Ways of Presenting and Critiquing Action Research Reports [1]     

Janet Clarke  Pete Dudley  Anne Edwards  Stephen Rowland  Charly Ryan  Richard Winter 《Educational Action Research》2013,21(3):490-492

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Sir Alan Peacock (ed.), Does The Past Have a Future? The Political Economy of Heritage; Michael Hutter and Ilde Rizzo (eds.), Economic Perspectives on Cultural Heritage     

Rosemary Clarke 《Journal of Cultural Economics》2000,24(3):257-260

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Tie Point Strategy in American and International Squash and Badminton     

Stephen R. Clarke 《Research quarterly for exercise and sport》2013,84(4):729-734

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Measuring the economic impact of the British library     

Caroline Pung  Ann Clarke  Laurie Patten 《New Review of Academic Librarianship》2013,19(1):79-102

Assessing the British Library's contribution to the national economy is a complex matter, requiring consideration of a number of different dimensions. First, the value added by the Library takes many forms—economic, cultural, social and intellectual. Second, the British Library adds value both to those who use our products and services directly, and to the wider UK population who benefit indirectly from the Library's existence and the services it provides. Traditionally, attempts to assess these benefits have taken the form of qualitative case studies—telling good stories, but failing to provide a comprehensive evaluation. But now a technique supported by the Nobel Prize winning economists, Kenneth Arrow and Robert Solow, permits a coherent quantitative evaluation of the total benefit to the nation of publicly funded institutions and programmes. Recognising the value of this technique, the British Library commissioned a groundbreaking research study to estimate the impact of the Library on the UK economy. The study demonstrates that the Library generates value of around 4.4 times the level of its annual public funding of £83m. To the best of our knowledge, this study represents the first time the ‘Contingent Valuation’ technique has been used to derive a figure for the overall economic impact of a national or major research library.  相似文献   

The Sage handbook of action research: participative inquiry and practice     

Maeve O'Grady 《Action Learning: Research and Practice》2013,10(2):195-199

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The influence of gravimetric moisture content on studded shoe–surface interactions in soccer     

James Clarke  Matt J. Carré 《Sports Engineering》2017,20(2):121-132

It is desirable for the studs of a soccer shoe to penetrate the sport surface and provide the player with sufficient traction when accelerating. Mechanical tests are often used to measure the traction of shoe–surface combinations. Mechanical testing offers a repeatable measure of shoe–surface traction, eliminating the inherent uncertainties that exist when human participant testing is employed, and are hence used to directly compare the performance of shoe–surface combinations. However, the influence specific surface characteristics has on traction is often overlooked. Examining the influence of surface characteristics on mechanical test results improves the understanding of the traction mechanisms at the shoe–surface interface. This allows footwear developers to make informed decisions on the design of studded outsoles. The aim of this paper is to understand the effect gravimetric moisture content has on the tribological mechanisms at play during stud–surface interaction. This study investigates the relationships between: the gravimetric moisture content of a natural sand-based soccer surface; surface stiffness measured via a bespoke impact test device; and surface traction measured via a bespoke mechanical test device. Regression analysis revealed that surface stiffness decreases linearly with increased gravimetric moisture content (p = 0.04). Traction was found to initially increase and then decrease with gravimetric moisture content. It was observed that: a surface of low moisture content provides low stud penetration and therefore reduced traction; a surface of high moisture content provides high stud penetration but also reduced traction due to a lubricating effect; and surfaces with moisture content in between the two extremes provide increased traction. In this study a standard commercially available stud was used and other studs may provide slightly different results. The results provide insight into the traction mechanisms at the stud–surface interface which are described in the paper. The variation between traction measurements shows the influence gravimetric moisture content will have on player performance. This highlights the requirement to understand surface conditions prior to making comparative shoe–surface traction studies and the importance of using a studded outsole that is appropriate to the surface condition during play.  相似文献   

Empiricism,Capacities and Experiments     

Clarke  Steve 《Science & Education》1999,8(4):363-374

Recent developments in Nancy Cartwright's philosophy are examined, against the background of her earlier ideas. The examination is structured around two related problems for the interpretation of Cartwright; how to understand Cartwright's claim that we can see capacities in experiments, and the question of whether Cartwright is entitled to call herself an empiricist. It is argued that we should understand Cartwright as allowing that the seeing of capacities in experiments can incorporate an interpretive aspect. It is further argued that, although Cartwright is a long way from contemporary Humean empiricists, her views can be understood as falling within the broad empiricist tradition. In the process of addressing these issues the role of idealization in Cartwright's thought is explained.  相似文献