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

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.     

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

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.     

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

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...     

Knowledge and Dignity in the Era of “Big Data”

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.     

纽约——繁荣与奢华的摇篮

在第82届奥斯卡颁奖晚会上,法国作品《商标的世界》（Logorama）获得了最佳动画短片奖,这部短片以让人应接不暇的商标对人们造成视觉冲击,几乎包罗了所有世界顶级的品牌。     

Science and technology management: Designing an undergraduate course

This research focusses on the role of science educators in preparing technically educated graduates for their careers. A comparison was made between the skills and abilities in science and technology students desired by industrial employers and whether New Zealand graduates exhibit these qualities. To address some of the management-based issues identified by the research, the design of a new Science and Technology Management course is outlined. Specializations: science and technology education, co-operative education, development of professional skills. Specializations: co-operative education programmes.