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Tuomo Korenius Jorma Laurikkala Martti Juhola Kalervo Järvelin 《Information Retrieval》2006,9(1):33-53
Search facilitated with agglomerative hierarchical clustering methods was studied in a collection of Finnish newspaper articles
(N = 53,893). To allow quick experiments, clustering was applied to a sample (N = 5,000) that was reduced with principal components analysis. The dendrograms were heuristically cut to find an optimal partition,
whose clusters were compared with each of the 30 queries to retrieve the best-matching cluster. The four-level relevance assessment
was collapsed into a binary one by (A) considering all the relevant and (B) only the highly relevant documents relevant, respectively.
Single linkage (SL) was the worst method. It created many tiny clusters, and, consequently, searches enabled with it had high
precision and low recall. The complete linkage (CL), average linkage (AL), and Ward's methods (WM) returned reasonably-sized
clusters typically of 18–32 documents. Their recall (A: 27–52%, B: 50–82%) and precision (A: 83–90%, B: 18–21%) was higher
than and comparable to those of the SL clusters, respectively. The AL and WM clustering had 1–8% better effectiveness than
nearest neighbor searching (NN), and SL and CL were 1–9% less efficient that NN. However, the differences were statistically
insignificant. When evaluated with the liberal assessment A, the results suggest that the AL and WM clustering offer better
retrieval ability than NN. Assessment B renders the AL and WM clustering better than NN, when recall is considered more important
than precision. The results imply that collections in the highly inflectional and agglutinative languages, such as Finnish,
may be clustered as the collections in English, provided that documents are appropriately preprocessed. 相似文献
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The aim of this study was to determine the physiological responses to orienteering by examining the interrelationships between the information provided by a differential global positioning system (dGPS) about an orienteer's route, speed and orienteering mistakes, portable metabolic gas analyser data during orienteering and data from incremental treadmill tests. Ten male orienteers completed a treadmill threshold test and a field test; the latter was performed on a 4.3 km course on mixed terrain with nine checkpoints. The anaerobic threshold, threshold of decompensated metabolic acidosis, respiratory exchange ratio, onset of blood lactate accumulation and peak oxygen uptake (VO2peak) were determined from the treadmill test. Time to complete the course, total distance covered, mean speed, distance and timing of orienteering mistakes, mean oxygen uptake, mean relative heart rate, mean respiratory exchange ratio and mean running economy were computed from the dGPS data and metabolic gas analyser data. Correlation analyses showed a relationship between a high anaerobic threshold and few orienteering mistakes (r = - 0.64, P < 0.05). A high threshold of decompensated metabolic acidosis and VO2peak were related to a fast overall time (r = -0.70 to -0.72, P < 0.05) and high running speed (r = 0.64 to 0.79, P < 0.05 and P < 0.01, respectively), and were thus the best predictors of performance. 相似文献
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Tuomo Erkki Virtanen Marja-Kristiina Lerkkanen Anna-Maija Poikkeus Matti Kuorelahti 《教育心理学》2015,35(8):963-983
Student engagement has been identified as an influential mediator between classroom interactional quality and adolescent learning outcomes. This study examined the relationship between classroom quality and student behavioural engagement in secondary school classrooms. Three dimensions of classroom quality (emotional, organisational and instructional support) and the dimension of student engagement were observed in nine classrooms using the Classroom Assessment Scoring System. Self-ratings of behavioural engagement were provided by 181 Finnish secondary school students along with their teachers’ ratings of classroom-level student engagement. The results showed, first, that there was variation in both classroom quality and student behavioural engagement between the classrooms. Second, classroom organisational support was associated with observed and with teacher- and student-rated engagement, and instructional support was associated with student-rated and observed engagement. Third, emotional support did not have a direct effect on student engagement but contributed to student engagement indirectly via organisational and instructional support. There were no gender differences with respect to self-reported engagement. Class size had a positive effect on teacher-rated engagement. The results demonstrated specific associations between the domains of classroom quality and student behavioural engagement in secondary school classrooms. 相似文献
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This study explored the causes of student disengagement from their doctoral studies in the biological and environmental sciences. The data came from interviews of 40 doctoral students (male?=?15, female?=?25) and underwent qualitative analysis for content. Our results showed that doctoral studies provide multiple contexts for disengagement, such as the scholarly community and supervision, while doctoral students’ sense of distress, cynicism and inefficacy emerged as central components of disengagement. The study identified isolation, indifference, and lack of support and constructive feedback as sources of cynicism, while distress and inefficacy were more often related to failure or lack of progress in research. Our findings indicate that the source of disengagement can vary not only between individuals, but also between the academic activities at hand. Thus, while promoting an engaging doctoral experience, awareness of what typically triggers disengagement in the doctoral journey is vital. 相似文献
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Suhonen Jarkko Sutinen Erkki 《Educational technology research and development : ETR & D》2022,70(5):1551-1573
Educational technology research and development - A critical aspect of designing and running online study programs is the identification of factors and elements that could potentially threaten the... 相似文献
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The aim of this study was to explore the relationships between prior knowledge, academic self‐beliefs, and previous study success in predicting the achievement of 139 students on a university mathematics course. Structural equation modelling was used to explore the interplay of these variables in predicting student achievement. The results revealed that domain‐specific prior knowledge was the strongest predictor of student achievement over and above other variables included in the model and, together with previous study success, explained 55% of the variance. Academic self‐beliefs strongly correlated with previous study success and had a strong direct influence on prior knowledge test performance. However, self‐beliefs predicted student achievement only indirectly via prior knowledge. The results imply that both prior knowledge and self‐beliefs should be taken into account when considering instructional support issues, because they can provide valuable insights about the future performance of the students. 相似文献
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Eeva Eskola Eeva-Leena Kataja Jukka Hyönä Tuomo Häikiö Juho Pelto Hasse Karlsson Linnea Karlsson Riikka Korja 《Child development》2021,92(4):1539-1553
To investigate the role of early regulatory problems (RP), such as problems in feeding, sleeping, and calming down during later development, the association between parent-reported RP at 3 months (no-RP, n = 110; RP, n = 66) and attention to emotional faces at 8 months was studied. Eight-month-old infants had a strong tendency to look at faces and to specifically fearful faces, and the individual variance in this tendency was assessed with eye tracking using a face-distractor paradigm. The early RPs were related to a lower attention bias to fearful faces compared to happy and neutral faces after controlling for temperamental negative affectivity. This suggests that early RPs are related to the processing of emotional information later during infancy. 相似文献
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T. E. Virtanen M.-K. Lerkkanen A.-M. Poikkeus M. Kuorelahti 《Scandinavian Journal of Educational Research》2018,62(4):519-537
Self-ratings of behavioural engagement, cognitive engagement and school burnout were used in person-centred analyses to identify latent profiles among 2,485 Finnish lower-secondary school students. Three profiles were identified: high-engagement/low-burnout (40.6% of the sample), average-engagement/average-burnout (53.9%), and low-engagement/high-burnout (5.5%). Another sample of lower-secondary school students was used to validate the 3 profiles. The factors most strongly associated with the high-engagement/low-burnout profile of lower-secondary school students’ were high levels of support from teachers and family, good academic performance, and lack of truancy. The study indicated that teacher and family support and students’ academic achievement are pivotal in understanding student engagement and school burnout. 相似文献