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Charles C. Webber 《Religious education (Chicago, Ill.)》2013,108(5):292-299
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A pipelined architecture for distributed text query evaluation 总被引：1，自引：0，他引：1
Alistair Moffat William Webber Justin Zobel Ricardo Baeza-Yates 《Information Retrieval》2007,10(3):205-231
Two principal query-evaluation methodologies have been described for cluster-based implementation of distributed information
retrieval systems: document partitioning and term partitioning. In a document-partitioned system, each of the processors hosts
a subset of the documents in the collection, and executes every query against its local sub-collection. In a term-partitioned
system, each of the processors hosts a subset of the inverted lists that make up the index of the collection, and serves them
to a central machine as they are required for query evaluation.
In this paper we introduce a pipelined query-evaluation methodology, based on a term-partitioned index, in which partially
evaluated queries are passed amongst the set of processors that host the query terms. This arrangement retains the disk read
benefits of term partitioning, but more effectively shares the computational load. We compare the three methodologies experimentally,
and show that term distribution is inefficient and scales poorly. The new pipelined approach offers efficient memory utilization
and efficient use of disk accesses, but suffers from problems with load balancing between nodes. Until these problems are
resolved, document partitioning remains the preferred method.
Alistair Moffat was supported by the Australian Research Council, the ARC Special Research Center for Perceptive and Intelligent
Machines in Complex Environments, and the NICTA Victoria Laboratory.
William Webber and Justin Zobel were supported by the Australian Research Council.
Ricardo Baeza-Yates was supported by Grant P01-029-F from Millennium Initiative of Mideplan, Chile; and by the University
of Melbourne as a visiting scholar at the time this project was undertaken. 相似文献
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Louise Webber 《Emotional and Behavioural Difficulties》2017,22(4):317-331
This article focuses on teachers’ experiences of supporting looked after and adopted children in one case study primary school in England. Children who are looked after and adopted may have a disrupted attachment with their primary carer which has resulted in an insecure attachment. Children with insecure attachments can feel anxious, uncertain and have low self-worth which can result in a struggle to adapt to school as they are unable to articulate their feelings. This article draws on qualitative research using semi-structured interviews with teaching staff in order to illuminate strategies, subsidised through Pupil Premium Plus funding, to support such children. A key outcome was the creation of a school-based model consisting of six main components that can be developed to support children with insecure attachments. 相似文献
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Dr. Charles F. Webber Ph.D. 《The Educational forum》2013,77(4):298-299
Over the past couple of decades, K–12 schools have courageously struggled with the concept of shared, or distributed, leadership; however, the basic landscape of K–12 school leadership remains heavily hierarchical. Nonetheless, teachers can share leadership. This article explores productive forms of teacher leadership that are models of collaboration, integration, encouragement, learning, modeling, challenging, building consensus, and displaying professionalism. 相似文献
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Ethics and Information Technology - This paper examines how digital technologies might be used to improve ethical attitudes towards nonhuman animals, by exploring the case study of nonhuman apes... 相似文献
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Shelleyann Scott Charles F. Webber Judy L. Lupart Nola Aitken Donald E. Scott 《Assessment in Education: Principles, Policy & Practice》2014,21(1):52-70
This paper focuses on promoting fairness and equity in student assessment practices. The researchers used questionnaires and interviews and the study encompassed a total of 3312 individuals representing a range of stakeholders. The paper is presented in two parts: fairness and discrimination, and challenging policy and practice. Five key principles emerged. Educators must strive to address the personal impact of assessment practices on individual students and their families. Assessment must be differentiated to accommodate the ability, social, cultural and linguistic background of students. All members of school communities must challenge the complacency associated with accepting indefensible assessment practices. The frequency, intensity and intrusiveness of assessments must not be overwhelming for students and their families. Finally, assessment must not be used to counter inappropriate student behaviour or reward desired behaviour. Implications for practice are presented. Additionally, the authors describe changes to policy and practice that occurred as a result of the study. 相似文献
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Charles F. Webber Shelleyann Scott E. Nola Aitken Judy Lupart Donald E. Scott 《School Leadership & Management》2013,33(3):240-255
This paper reports the leadership findings that emerged from the Alberta Student Assessment Study, a large-scale study employing a mixed-method design. Findings included the importance of assessment leadership, credibility of leaders, capacity to make hard decisions and ability to lead professional learning. An optimal assessment leadership profile emerged which includes values and assessment knowledge, mediated by personal qualities and accompanied by an interplay between procedural knowledge and professional skills. This informs leadership vision and actions leading to increased assessment literacy, more effective monitoring and reporting practice, enhanced instructional practice, enriched partnerships with parents and community members and positive student outcomes. 相似文献
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Using detailed individual-level data from public universities in the state of Ohio, I estimate the effect of various institutional expenditures on the probability of graduating from college. Using a competing risks regression framework, I find differential impacts of expenditure categories across student characteristics. I estimate that student service expenditures have a larger impact on students with low SAT/ACT scores, while instructional expenditures are more important for high test score students and those majoring in scientific/quantitative fields. The individual-level nature of these data allows me to address measurement error and endogeneity concerns the previous literature has been unable to deal with. 相似文献