Using the Information Structure Model to Compare Profile-Based Information Filtering Systems

In the IR field it is clear that the value of a system depends on the cost and benefit profiles of its users. It would seem obvious that different users would prefer different systems. In the TREC-9 filtering track, systems are evaluated by a utility measure specifying a given cost and benefit. However, in the study of decision systems it is known that, in some cases, one system may be unconditionally better than another. In this paper we employ a decision theoretic approach to find conditions under which an Information Filtering (IF) system is unconditionally superior to another for all users regardless of their cost and benefit profiles.It is well known that if two IF systems have equal precision the system with better recall will be preferred by all users. Similarly, with equal recall, better precision is universally preferred. We confirm these known results and discover an unexpected dominance relation in which a system with lower recall will be universally preferred provided its precision is sufficiently higher.     

Cognitive deficits in reading disability and attention deficit disorder

This paper presents data from three studies (a cross-sectional study of school-referred children, a test-retest study of subtypes of reading disabilities, and a study of a large, random sample of first graders) that focus on specifying the cognitive deficits associated with reading difficulties and separating them from those associated with attentional deficits. The cognitive deficits associated with difficulty in reading were consistent across samples, developmental levels, definitions, and subtypes of reading disabilities. With IQ, age, and sex controlled for, poor readers were significantly impaired on measures of naming and phonological awareness. The effects of attentional deficits were more variable and complex but were clearly separate from the reading disability effects.     

HIGH SCHOOL STUDENTS’ PROFICIENCY AND CONFIDENCE LEVELS IN DISPLAYING THEIR UNDERSTANDING OF BASIC ELECTROLYSIS CONCEPTS

This study was conducted with 330 Form 4 (grade 10) students (aged 15??C?16?years) who were involved in a course of instruction on electrolysis concepts. The main purposes of this study were (1) to assess high school chemistry students?? understanding of 19 major principles of electrolysis using a recently developed 2-tier multiple-choice diagnostic instrument, the Electrolysis Diagnostic Instrument (EDI), and (2) to assess students?? confidence levels in displaying their knowledge and understanding of these electrolysis concepts. Analysis of students?? responses to the EDI showed that they displayed very limited understanding of the electrolytic processes involving molten compounds and aqueous solutions of compounds, with a mean score of 6.82 (out of a possible maximum of 17). Students were found to possess content knowledge about several electrolysis processes but did not provide suitable explanations for the changes that had occurred, with less than 45?% of students displaying scientifically acceptable understandings about electrolysis. In addition, students displayed limited confidence about making the correct selections for the items; yet, in 16 of the 17 items, the percentage of students who were confident that they had selected the correct answer to an item was higher than the actual percentage of students who correctly answered the corresponding item. The findings suggest several implications for classroom instruction on the electrolysis topic that need to be addressed in order to facilitate better understanding by students of electrolysis concepts.     

An investigation of the approach to learning of Nepalese tertiary students

This investigation with 342 Nepalese tertiary students indicates that current conceptions of approaches to learning are relevant to these students. Factor analysis of the Study Process Questionnaire (SPQ) also suggests that the structure of learning processes is similar for Nepalese, Australian, and Filipino students. Internal locus of control also seems to be a factor in the adoption of deep and achieving approaches to learning in each of these cultures. Evidence of differences in secondary and tertiary student approaches to learning within Nepal and comparisons between Nepalese and Australian tertiary students' approaches to learning are also presented.     

The Role of Sex of Peers and Gender‐Typed Activities in Young Children's Peer Affiliative Networks: A Longitudinal Analysis of Selection and Influence

A stochastic actor‐based model was used to investigate the origins of sex segregation by examining how similarity in sex of peers and time spent in gender‐typed activities affected affiliation network selection and how peers influenced children's (N = 292; M_age = 4.3 years) activity involvement. Gender had powerful effects on interactions through direct and indirect pathways. Children selected playmates of the same sex and with similar levels of gender‐typed activities. Selection based on gender‐typed activities partially mediated selection based on sex of peers. Children influenced one another's engagement in gender‐typed activities. When mechanisms producing sex segregation were compared, the largest contributor was selection based on sex of peers; less was due to activity‐based selection and peer influence. Implications for sex segregation and gender development are discussed.