A study of results overlap and uniqueness among major Web search engines     

Amanda Spink  Bernard J. Jansen  Chris Blakely  Sherry Koshman 《Information processing & management》2006

The performance and capabilities of Web search engines is an important and significant area of research. Millions of people world wide use Web search engines very day. This paper reports the results of a major study examining the overlap among results retrieved by multiple Web search engines for a large set of more than 10,000 queries. Previous smaller studies have discussed a lack of overlap in results returned by Web search engines for the same queries. The goal of the current study was to conduct a large-scale study to measure the overlap of search results on the first result page (both non-sponsored and sponsored) across the four most popular Web search engines, at specific points in time using a large number of queries. The Web search engines included in the study were MSN Search, Google, Yahoo! and Ask Jeeves. Our study then compares these results with the first page results retrieved for the same queries by the metasearch engine Dogpile.com. Two sets of randomly selected user-entered queries, one set was 10,316 queries and the other 12,570 queries, from Infospace’s Dogpile.com search engine (the first set was from Dogpile, the second was from across the Infospace Network of search properties were submitted to the four single Web search engines). Findings show that the percent of total results unique to only one of the four Web search engines was 84.9%, shared by two of the three Web search engines was 11.4%, shared by three of the Web search engines was 2.6%, and shared by all four Web search engines was 1.1%. This small degree of overlap shows the significant difference in the way major Web search engines retrieve and rank results in response to given queries. Results point to the value of metasearch engines in Web retrieval to overcome the biases of individual search engines.  相似文献   

Theory of mind and social interest in zero-acquaintance play situations     

Moore C  Bosacki SL  Macgillivray S 《Child development》2011,82(4):1163-1172

Many studies have examined associations between children's theory of mind and social behavior with familiar peers, but to date none have examined how theory of mind might relate to behavior toward unfamiliar peers in a play setting. Forty-four 4-year-olds (21 girls, 23 boys) participated in standard theory-of-mind tasks and in a play session with 3 or 4 other children who were unfamiliar. Children were also tested on general vocabulary ability. No relations were found between theory of mind and social engagement. However, positive associations were found between theory of mind and time spent observing, but not interacting with, other children. Possible explanations of the links between theory of mind, temperament, and social interest are considered.  相似文献   

How publishers and editors can help early career researchers: Recommendations from a roundtable discussion     

Anna O'Brien  Chris Graf  Kate McKellar 《Learned Publishing》2019,32(4):383-393

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The sum of its parts: reducing sparsity in click estimation with query segments     

Dustin Hillard  Eren Manavoglu  Hema Raghavan  Chris Leggetter  Erick Cantú-Paz  Rukmini Iyer 《Information Retrieval》2011,14(3):315-336

The critical task of predicting clicks on search advertisements is typically addressed by learning from historical click data. When enough history is observed for a given query-ad pair, future clicks can be accurately modeled. However, based on the empirical distribution of queries, sufficient historical information is unavailable for many query-ad pairs. The sparsity of data for new and rare queries makes it difficult to accurately estimate clicks for a significant portion of typical search engine traffic. In this paper we provide analysis to motivate modeling approaches that can reduce the sparsity of the large space of user search queries. We then propose methods to improve click and relevance models for sponsored search by mining click behavior for partial user queries. We aggregate click history for individual query words, as well as for phrases extracted with a CRF model. The new models show significant improvement in clicks and revenue compared to state-of-the-art baselines trained on several months of query logs. Results are reported on live traffic of a commercial search engine, in addition to results from offline evaluation.  相似文献   

Agreement in activity energy expenditure assessed by accelerometer and self-report in adolescents: variation by sex, age, and weight status     

Machado-Rodrigues AM  Coelho-E-Silva MJ  Mota J  Cyrino E  Cumming SP  Riddoch C  Beunen G  Malina RM 《Journal of sports sciences》2011,29(14):1503-1514

The agreement between self-reported and objective estimates of activity energy expenditure was evaluated in adolescents by age, sex, and weight status. Altogether, 403 participants (217 females, 186 males) aged 13-16 years completed a 3-day physical activity diary and wore a GT1M accelerometer on the same days. Partial correlations (controlling for body mass) were used to determine associations between estimated activity energy expenditure (kcal · min(-1)) from the diary and accelerometry. Differences in the magnitude of the correlations were examined using Fisher's r to z transformations. Bland-Altman procedures were used to determine concordance between the self-reported and objective estimates. Partial correlations between assessments of activity energy expenditure (kcal · min(-1)) did not differ significantly by age (13-14 years: r = 0.41; 15-16 years: r = 0.42) or weight status (normal weight: r = 0.42; overweight: r = 0.39). The magnitude of the association was significantly affected by sex (Δr = 0.11; P < 0.05). The agreement was significantly higher in males than in females. The relationship between activity energy expenditure assessed by the objective method and the 3-day diary was moderate (controlling for weight, correlations ranged between 0.33 and 0.44). However, the 3-day diary revealed less agreement in specific group analyses; it markedly underestimated activity energy expenditure in overweight/obese and older adolescents. The assessment of activity energy expenditure is complex and may require a combination of methods.  相似文献   

Prosocial and antisocial behavior in sport: the role of coaching style, autonomous vs. controlled motivation, and moral disengagement     

Hodge K  Lonsdale C 《运动与训练心理学杂志》2011,33(4):527-547

The purpose of this study was to examine whether the relationships between contextual factors (i.e., autonomy-supportive vs. controlling coaching style) and person factors (i.e., autonomous vs. controlled motivation) outlined in self-determination theory (SDT) were related to prosocial and antisocial behaviors in sport. We also investigated moral disengagement as a mediator of these relationships. Athletes' (n = 292, M = 19.53 years) responses largely supported our SDT-derived hypotheses. Results indicated that an autonomy-supportive coaching style was associated with prosocial behavior toward teammates; this relationship was mediated by autonomous motivation. Controlled motivation was associated with antisocial behavior toward teammates and antisocial behavior toward opponents, and these two relationships were mediated by moral disengagement. The results provide support for research investigating the effect of autonomy-supportive coaching interventions on athletes' prosocial and antisocial behavior.  相似文献   

Are Elementary Preservice Teachers Floating or Sinking in Their Understanding of Buoyancy?     

Harrell  Pamela Espr&#;valo  Kirby  Benjamin  Subramaniam  Kartheyan  Long  Chris 《International Journal of Science and Mathematics Education》2022,20(2):299-320

International Journal of Science and Mathematics Education - This research study investigated conceptions about buoyancy held by 55 elementary preservice teachers enrolled in a science methods...  相似文献   

Using Drawing Technology to Assess Students’ Visualizations of Chemical Reaction Processes     

Hsin-Yi Chang  Chris Quintana  Joseph Krajcik 《Journal of Science Education and Technology》2014,23(3):355-369

In this study, we investigated how students used a drawing tool to visualize their ideas of chemical reaction processes. We interviewed 30 students using thinking-aloud and retrospective methods and provided them with a drawing tool. We identified four types of connections the students made as they used the tool: drawing on existing knowledge, incorporating dynamic aspects of chemical processes, linking a visualization to the associated chemical phenomenon, and connecting between the visualization and chemistry concepts. We also compared students who were able to create dynamic visualizations with those who only created static visualizations. The results indicated a relationship between students constructing a dynamic view of chemical reaction processes and their understanding of chemical reactions. This study provides insights into the use of visualizations to support instruction and assessment to facilitate students’ integrated understanding of chemical reactions.  相似文献   

Suicidal Behavior and Help Seeking Among Diverse College Students          下载免费PDF全文

Chris Brownson  Martin Swanbrow Becker  Richard Shadick  Shanna S. Jaggars  Yael Nitkin‐Kaner 《Journal of College Counseling》2014,17(2):116-130

Suicidal and help‐seeking behaviors of students of color remain a significant problem on college campuses. Self‐reported suicidal experiences and help‐seeking behavior of diverse students are examined on the basis of results from a national survey of college student mental health. The results suggest significant differences in the expression of suicidal thoughts and behavior across racial and ethnic groups and different experiences in their referral for, and utilization of, professional help.  相似文献   

Knowledge and Dignity in the Era of “Big Data”     

Siva Vaidhyanathan  Chris Bulock 《期刊图书馆员》2014,66(1-4):49-64

Private companies and government agencies are now creating and tapping into vastly more data than ever before. These data flows include enormous amounts of personal information and raise questions about privacy and intellectual policy that could have profound impacts on our lives. While data collection and creation are nearly ubiquitous, the instruments of collection and analysis are often hidden in order to track more natural behavior. Recent revelations of massive governmental data collection offer the country, and librarians in particular, an opportunity to discuss and question the societal implications of “Big Data,” and the policies that govern them.  相似文献