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In this paper, we define and present a comprehensive classification of user intent for Web searching. The classification consists of three hierarchical levels of informational, navigational, and transactional intent. After deriving attributes of each, we then developed a software application that automatically classified queries using a Web search engine log of over a million and a half queries submitted by several hundred thousand users. Our findings show that more than 80% of Web queries are informational in nature, with about 10% each being navigational and transactional. In order to validate the accuracy of our algorithm, we manually coded 400 queries and compared the results from this manual classification to the results determined by the automated method. This comparison showed that the automatic classification has an accuracy of 74%. Of the remaining 25% of the queries, the user intent is vague or multi-faceted, pointing to the need for probabilistic classification. We discuss how search engines can use knowledge of user intent to provide more targeted and relevant results in Web searching. 相似文献
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Emma Blakey Danielle Matthews Lucy Cragg Jessica Buck David Cameron Ben Higgins Lisa Pepper Ellen Ridley Emma Sullivan Daniel J. Carroll 《Child development》2020,91(5):1594-1614
The socioeconomic attainment gap in mathematics starts early and increases over time. This study aimed to examine why this gap exists. Four-year-olds from diverse backgrounds were randomly allocated to a brief intervention designed to improve executive functions (N = 87) or to an active control group (N = 88). The study was preregistered and followed CONSORT guidelines. Executive functions and mathematical skills were measured at baseline, 1 week, 3 months, 6 months, and 1 year posttraining. Executive functions mediated the relation between socioeconomic status and mathematical skills. Children improved over training, but this did not transfer to untrained executive functions or mathematics. Executive functions may explain socioeconomic attainment gaps, but cognitive training directly targeting executive functions is not an effective way to narrow this gap. 相似文献
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We have previously reported that microthrottle pumps (MTPs) display the capacity to pump solid phase suspensions such as polystyrene beads which prove challenging to most microfluidic pumps. In this paper we report employing a linear microthrottle pump (LMTP) to pump whole, undiluted, anticoagulated, human venous blood at 200 μl min(-1) with minimal erythrocyte lysis and no observed pump blockage. LMTPs are particularly well suited to particle suspension transport by virtue of their relatively unimpeded internal flow-path. Micropumping of whole blood represents a rigorous real-world test of cell suspension transport given blood's high cell content by volume and erythrocytes' relative fragility. A modification of the standard Drabkin method and its validation to spectrophotometrically quantify low levels of erythrocyte lysis by hemoglobin release is also reported. Erythrocyte lysis rates resulting from transport via LMTP are determined to be below one cell in 500 at a pumping rate of 102 μl min(-1). 相似文献
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EAST: Developing an electronic assessment and storage tool 总被引:2,自引:2,他引:0
Katherine I. Edwards Eugenia Fernandez Tracey M. Milionis David M. Williamson 《Assessment & Evaluation in Higher Education》2002,27(1):95-104
Assessment is an ongoing process that evaluates samples of completed student assignments to determine whether the underlying curriculum effectively produces the desired learning outcomes. Each year, the current system of tracking and storing artefacts for assessment becomes increasingly difficult. Compiling the results is a time-consuming process. EAST provides a cohesive web-based solution for managing assessment artefacts. EAST aids the assessment effort through the ability to easily store artefacts in electronic form, support and record the assessment of student work, and ease the development of reports. This paper discusses the analysis, development and features of EAST. The first section discusses the analysis phase of the project, highlighting the system objectives and the requirements of the EAST system. The second section details how the EAST system was developed and implemented. In the last section, features of the system are described and its contribution to the school's assessment effort is discussed. 相似文献
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