Efficient online index maintenance for contiguous inverted lists

Search engines and other text retrieval systems use high-performance inverted indexes to provide efficient text query evaluation. Algorithms for fast query evaluation and index construction are well-known, but relatively little has been published concerning update. In this paper, we experimentally evaluate the two main alternative strategies for index maintenance in the presence of insertions, with the constraint that inverted lists remain contiguous on disk for fast query evaluation. The in-place and re-merge strategies are benchmarked against the baseline of a complete re-build. Our experiments with large volumes of web data show that re-merge is the fastest approach if large buffers are available, but that even a simple implementation of in-place update is suitable when the rate of insertion is low or memory buffer size is limited. We also show that with careful design of aspects of implementation such as free-space management, in-place update can be improved by around an order of magnitude over a naïve implementation.     

Representational guidance and student engagement: examining designs for collaboration in online synchronous environments

In this paper we report the results of a study which investigated the affordances of multi-user virtual environments (MUVEs) for collaborative learning from a design perspective. Utilizing a mixed methods approach, we conducted a comparative study of the effect of varying representational and interactional design features on a collaborative design activity in three online synchronous environments. We compared environments featuring multiple modes of interaction (MUVEs), shared representations (text chat and 2D still images) and text-only features. Sixty-one students enrolled in an undergraduate course on Child Development participated in the study. Participants were asked to design a theoretically-based, developmentally appropriate, preschool classroom setting. Students were randomly assigned to one of three online learning environments that provided varying levels of representation and interaction. Significant differences in collaborative problem solving interactions were found. Participants in the shared representations + text condition evidenced stronger learning outcomes as regards substantive discussion and integration of child development concepts; while participants in the MUVE condition reported the most enjoyment with the experience. These findings are explained by the concepts of representational guidance, representational bias, educational affordances and interface design metaphors. Suggestions for the design of MUVEs for collaborative learning are provided.     

So,are early career researchers the harbingers of change?

This article provides the final results of a 3‐year study that sought to discover whether early career researchers (ECRs) were the harbingers of change with respect to scholarly communications. Over a hundred science and social science ECRs from seven countries, spanning three continents, were depth‐interviewed annually for 3 years (2016–2018) about their attitudes and behaviours with respect to 23 scholarly issues and activities (aspects). In order to provide an accessible overarching assessment of an extremely large and complex dataset, the interview data were categorized according to the strength and direction of change exhibited and the trends and points of interest raised. Results show that all ECRs have changed in one way or another, and a small minority has changed greatly in both attitude and practice and that collaboration and research impact are the scholarly aspects where most changes have occurred, and the greatest cause of change is not so much new technology as a change of jobs.     

A Meta-Analysis of Interventions to Improve Reading Comprehension Outcomes for Adolescents with Reading Difficulties

This meta-analysis synthesized 97 effect sizes extracted from 37 intervention studies for students with reading difficulties (RDs) in Grades 6 to 12 published between 1982 and 2021 to identify the overall impact of reading interventions and the moderating effects of intervention characteristics and study design characteristics. Random-effects robust variance estimation (RVE) was used to account for dependencies within studies. Overall, interventions designed to improve reading comprehension outcomes for adolescents with RDs were effective (g = 0.63). Meta-regression analyses identified several significant moderators that were associated with intervention efficacy, such as text content, duration of intervention, agent of intervention, status of student, type of dependent measure, and study quality. We provide study limitations as well as implications for research and practice.     

Public funds and local biotechnology firm creation

A long stream of academic literature has established that public funding towards research and development matters for economic growth because it relates to increases in innovation, productivity and the like. The impact of public funding on the creation of new firms has received less attention in this literature despite theoretical constructs that support such association. In the present paper we study whether indeed there is a relationship between public research funds and local firm births in the context of the U.S. biotechnology industry. In doing so, we introduce a number of changes that strengthen the robustness of our findings when compared with existing literature. These changes include a direct measure of research expenditures and a considerably lengthier longitudinal dataset which allows us to capture a structural relationship and not a chance event. We empirically demonstrate that increases in the level of research funding from the National Institutes of Health towards biotechnology associate with increases in the number of biotechnology firm births at the Metropolitan Statistical Area level. Further, we reveal that public funds towards established firms associate with local firm births considerably more strongly when compared with funds towards universities and research institutes/hospitals. We conclude the paper with academic and policy implications of the present work that highlight the complexity of factors that underlie the creation of local firms in high technology industries.     

Determination of football pitch locations from video footage and official pitch markings

The ability to determine a specific location on a football (soccer) pitch from television footage would provide a cost-effective method of obtaining competition-specific information on many professional and international teams. This study presents the accuracy and reliability of a new method of calculating ball location from simulated television coverage and known pitch markings. The coordinates of 99 markers of known location on a football pitch were digitized from video. An intersection point was determined from the equations of two lines that form pitch markings and the relationship from this point to other known pitch coordinates was calculated using a curve-fitting based method. Average error between known and reconstructed measures was 0.21 m for pitch width and 0.11 m for pitch length from a view simulating television coverage. Inter- and intra-rater reliability analyses showed researchers could consistently reconstruct pitch locations to within less than half a metre. The accuracy and reliability of this method will be sufficient for most practical uses in an applied sport environment, although the level of accuracy required will depend on the specific application. This method could be applied to other sports to determine specific locations on a pitch or court or to improve current competition analysis systems.     

Age and sex differences in motor performance of pre‐school Nigerian children

Differences in motor performance according to chronological age and gender of 341 young Nigerian children (ages 3 to 5) were examined. Motor test items designed by Morris et al. (1981) were administered to the subjects. Analysis of variance was used to determine significant differences in the motor performance of the groups. In the whole sample, more age differences than sex differences in performance were noted. Except for the balancing and running performances of the girls, a fairly linear trend of improvement with age was observed in the motor performances of the groups. At each age level the boys consistently performed better than the girls in four of the six motor tests (catching, standing long jump, tennis ball throw and speed run). Generally, the 4‐ and 5‐year‐old children performed homogeneously, with a great disparity in performance noted for the 3‐year‐old children. The results of this study confirm that age and sex differences in motor performance occur at early childhood. Prospective studies should seek to control the extraneous factors which influence motor development and account for the observed differences in motor performance of pre‐school children.     

An objective method for depicting team performance in elite professional rugby union

Abstract

Using a two-study approach, we examined a methodology for objectively depicting team performance and form in a professional rugby union side. Study 1 developed standardized indicators to examine a team's performance in a single match relative to their previous matches over a domestic season via a performance report and form chart. This resulted in standardized performance indicators that provided instant and coherent feedback on the team's performance relative to previous standards. Study 2 then utilized this methodology to compare a match between two professional sides, played the following season, to assess the extent to which the performance by one team affected that of the other. Comparison of the two teams' performances, for the match they played against each other, identified a drop in relative performance (against previous standards) for both teams on the same performance indicators. This appeared to be due to the match being a close, hard-fought contest particularly in the tackle and around the gain-line. The findings of the two studies suggest an accurate and viable methodology for depicting team performance that is superior to the global measures previously adopted. Presenting teams' current standardized performances (i.e. form) on a single visual scale also has utility for coaches within an applied setting. Future research should further investigate the effect of one team's performance on another through both individual and team outcomes.