title: Feature subset selection: a correlation based filter approach

authors: Hall, Mark A.

subjects: computer science

abstract: Recent work has shown that feature subset selection can have a position affect on the performance of machine learning algorithms. Some algorithms can be slowed or their performance adversely affected by too much data some of which may be irrelevant or redundant to the learning task. Feature subset selection, then, is a method of enhancing the performance of learning algorithms, reducing the hypothesis search space, and, in some cases, reducing the storage requirement. This paper describes a feature subset selector that uses a correlation based heuristic to determine the goodness of feature subsets, and evaluates its effectiveness with three common ML algorithms: a  decision tree inducer (C4.5), a naive Bayes classifier, and an instance based learner(IBI). Experiments using a number of standard data sets drawn from real and artificial domains are presented. Feature subset selection gave significant improvement for all three algorithms; C4.5 generated smaller decision trees.

text: Feature subset selection: a correlation based filter approach Recent work has shown that feature subset selection can have a position affect on the performance of machine learning algorithms. Some algorithms can be slowed or their performance adversely affected by too much data some of which may be irrelevant or redundant to the learning task. Feature subset selection, then, is a method of enhancing the performance of learning algorithms, reducing the hypothesis search space, and, in some cases, reducing the storage requirement. This paper describes a feature subset selector that uses a correlation based heuristic to determine the goodness of feature subsets, and evaluates its effectiveness with three common ML algorithms: a  decision tree inducer (C4.5), a naive Bayes classifier, and an instance based learner(IBI). Experiments using a number of standard data sets drawn from real and artificial domains are presented. Feature subset selection gave significant improvement for all three algorithms; C4.5 generated smaller decision trees.

year: 1997

title: Parental perceptions of the role of Applied Behaviour Analysis intervention for children with autism during the transition from early childhood education settings to primary school

authors: Stebletsova, Galina

subjects: child with autism

abstract: The transition to school time for children with autism may represent a period of an increased stress for the whole family. Some parents choose to try the Applied Behaviour Analysis (ABA) intervention for their children as a way of reducing that stress and to assist the child’s transition. This study focuses on the role the ABA intervention might play during this period of time from a parental point of view. 
A qualitative approach grounded in an interpretive methodology has been used for this study. Data were collected through nine families participating in email surveys, and four of them then agreed to participate in semi-structured follow-up interviews. In all nine families, the ABA intervention of various intensity had happened with when their children were transitioning from pre-school settings to primary school. Three themes emerged in the course of the study: ABA intervention, even though chosen to facilitate the transition phase, does not seem to be the only factor that contributes to the successful transition to school; Language skills improvement with help of ABA therapy during transition time is seen as a stress decreasing factor; The influence of the ABA intervention during transition time was not always positive towards the younger siblings.
All nine families emphasised that the financial aspect of the ABA intervention (namely, high cost) was seen as an extra stress factor during transition to school time. The high cost of the therapy was also linked to this study’s difficulties with recruitment. 
The findings, although only limited to the perspectives of nine participants, highlight the importance of families with children with autism to be prepared for the possible challenges during transition to school time. They also demonstrate the importance of further study in the field of the role of early interventions during transition phases of the young children with autism and imply that other factors apart from the interventions might play an important role in a child’s with autism transition to school time.

text: Parental perceptions of the role of Applied Behaviour Analysis intervention for children with autism during the transition from early childhood education settings to primary school The transition to school time for children with autism may represent a period of an increased stress for the whole family. Some parents choose to try the Applied Behaviour Analysis (ABA) intervention for their children as a way of reducing that stress and to assist the child’s transition. This study focuses on the role the ABA intervention might play during this period of time from a parental point of view. 
A qualitative approach grounded in an interpretive methodology has been used for this study. Data were collected through nine families participating in email surveys, and four of them then agreed to participate in semi-structured follow-up interviews. In all nine families, the ABA intervention of various intensity had happened with when their children were transitioning from pre-school settings to primary school. Three themes emerged in the course of the study: ABA intervention, even though chosen to facilitate the transition phase, does not seem to be the only factor that contributes to the successful transition to school; Language skills improvement with help of ABA therapy during transition time is seen as a stress decreasing factor; The influence of the ABA intervention during transition time was not always positive towards the younger siblings.
All nine families emphasised that the financial aspect of the ABA intervention (namely, high cost) was seen as an extra stress factor during transition to school time. The high cost of the therapy was also linked to this study’s difficulties with recruitment. 
The findings, although only limited to the perspectives of nine participants, highlight the importance of families with children with autism to be prepared for the possible challenges during transition to school time. They also demonstrate the importance of further study in the field of the role of early interventions during transition phases of the young children with autism and imply that other factors apart from the interventions might play an important role in a child’s with autism transition to school time.

year: 2013

title: Perceptions, expectations and interactions: a study of teachers and pupils in five ethnically mixed primary classrooms

authors: St George, Alison

abstract: Teachers’ perceptions of their pupils, expectations for pupil general ability, teacher-pupil interaction and pupil achievement were investigated in this naturalistic study of 5 teachers and 90 pupils in their New Zealand ethnically mixed Standard 3 classrooms.
A pilot study showed that teachers at this level tended to perceive pupils in terms of constructs reflecting academic work skills, home background and personal/social attributes. Using rating scales developed from the pilot study it was apparent that the teachers had a conception of the ideal pupil. It was suggested that this influenced expectations for pupils’ ability to do well at school. Girls and Pakeha pupils were seen as being closer to the ideal pupil stereotype than boys or Polynesian pupils, and for Polynesian pupils this was reflected in lower teacher expectations. Teacher expectations tended to be borne out by standardized achievement test results and accounted for a large proportion of teacher rated achievement variance. Ethnic group made a small but significant independent contribution to achievement variance on two of the Progressive Achievement Tests and on teacher rated achievement.
Using data on teacher-pupil dyadic interaction collected with the Brophy-Good system, contrasting patterns of interaction were noted between expectation groups (high, middle and low teacher expectations). The differences were largely qualitative and there were no expectation group differences in the total number of public or private dyadic interactions. High expectation pupils initiated more contacts with the teacher, answered more open public academic questions and received a lot less criticism for work or behaviour than the other groups. The low expectation group experienced a greater proportion of teacher initiated contacts and were asked more direct public academic questions which were of the product rather than the process type. The middle expectation group generally fell in between the high and low groups, but received the most criticism and the highest proportion of process questions. Teachers appeared to be attempting to prevent inequalities in quantity of interaction and this was discussed in terms of the perception of pupil attributes. Expectation group differences in interaction were not always the same for boys and girls or for all teachers. Despite the differences in teachers’ perceptions and expectations for Polynesian and Pakeha pupils, no ethnic group differences in teacher-pupil interaction were evidenced. 
No consistent and clear-cut expectation group differences were found in pupils’ perceptions of teacher behaviour. There was a moderate positive correlation between perception of the quantity of teacher contact and observed interaction but not regarding the affective quality of teacher contacts. 
The findings were discussed in terms of the theory and research on person perception and expectation phenomena in interpersonal behaviour. Some practical implications for educational practice were commented upon.

text: Perceptions, expectations and interactions: a study of teachers and pupils in five ethnically mixed primary classrooms Teachers’ perceptions of their pupils, expectations for pupil general ability, teacher-pupil interaction and pupil achievement were investigated in this naturalistic study of 5 teachers and 90 pupils in their New Zealand ethnically mixed Standard 3 classrooms.
A pilot study showed that teachers at this level tended to perceive pupils in terms of constructs reflecting academic work skills, home background and personal/social attributes. Using rating scales developed from the pilot study it was apparent that the teachers had a conception of the ideal pupil. It was suggested that this influenced expectations for pupils’ ability to do well at school. Girls and Pakeha pupils were seen as being closer to the ideal pupil stereotype than boys or Polynesian pupils, and for Polynesian pupils this was reflected in lower teacher expectations. Teacher expectations tended to be borne out by standardized achievement test results and accounted for a large proportion of teacher rated achievement variance. Ethnic group made a small but significant independent contribution to achievement variance on two of the Progressive Achievement Tests and on teacher rated achievement.
Using data on teacher-pupil dyadic interaction collected with the Brophy-Good system, contrasting patterns of interaction were noted between expectation groups (high, middle and low teacher expectations). The differences were largely qualitative and there were no expectation group differences in the total number of public or private dyadic interactions. High expectation pupils initiated more contacts with the teacher, answered more open public academic questions and received a lot less criticism for work or behaviour than the other groups. The low expectation group experienced a greater proportion of teacher initiated contacts and were asked more direct public academic questions which were of the product rather than the process type. The middle expectation group generally fell in between the high and low groups, but received the most criticism and the highest proportion of process questions. Teachers appeared to be attempting to prevent inequalities in quantity of interaction and this was discussed in terms of the perception of pupil attributes. Expectation group differences in interaction were not always the same for boys and girls or for all teachers. Despite the differences in teachers’ perceptions and expectations for Polynesian and Pakeha pupils, no ethnic group differences in teacher-pupil interaction were evidenced. 
No consistent and clear-cut expectation group differences were found in pupils’ perceptions of teacher behaviour. There was a moderate positive correlation between perception of the quantity of teacher contact and observed interaction but not regarding the affective quality of teacher contacts. 
The findings were discussed in terms of the theory and research on person perception and expectation phenomena in interpersonal behaviour. Some practical implications for educational practice were commented upon.

year: 1978