title: A refinement theory for μ∼Charts

authors: Reeve, Greg

abstract: The language μ-Charts is one of many Statechart-like languages, a family of visual languages that are used for designing reactive systems. We introduce a logic for reasoning about and constructing refinements for μ-Charts. The logic itself is interesting and important because it allows reasoning about μ-charts in terms of partial relations rather than the more traditional traces approach. The method of derivation of the logic is also worthy of report. AZ-based model for the language μ-Charts is constructed and the existing logic and refinement calculus of Z is used as the basis for the logic of μ-Charts. As well as describing the logic we introduce some of the ways such a logic can be used to reason about properties of μ-Charts and the refinement of abstract specifications into concrete realisations of reactive systems.
A refinement theory for Statechart-like languages is an important contribution because it allows us to formally investigate and reason about properties of the object language μ-Charts. In particular, we can conjecture and prove general properties required of the object language. This allows us to contrast possible language design decisions and comment on their consequences with respect to the design of Statechart-like languages. 
This thesis gives a comprehensive description of the μ-Charts language and details the development of a partial relations based logic and refinement calculus for the language. The logic and refinement calculus are presented as natural deduction style proof rules that allow us to give formal proofs of language properties and provide the basis for a formal program development framework. The notion of refinement that is encoded by the refinement rules is also extensively investigated.

text: A refinement theory for μ∼Charts The language μ-Charts is one of many Statechart-like languages, a family of visual languages that are used for designing reactive systems. We introduce a logic for reasoning about and constructing refinements for μ-Charts. The logic itself is interesting and important because it allows reasoning about μ-charts in terms of partial relations rather than the more traditional traces approach. The method of derivation of the logic is also worthy of report. AZ-based model for the language μ-Charts is constructed and the existing logic and refinement calculus of Z is used as the basis for the logic of μ-Charts. As well as describing the logic we introduce some of the ways such a logic can be used to reason about properties of μ-Charts and the refinement of abstract specifications into concrete realisations of reactive systems.
A refinement theory for Statechart-like languages is an important contribution because it allows us to formally investigate and reason about properties of the object language μ-Charts. In particular, we can conjecture and prove general properties required of the object language. This allows us to contrast possible language design decisions and comment on their consequences with respect to the design of Statechart-like languages. 
This thesis gives a comprehensive description of the μ-Charts language and details the development of a partial relations based logic and refinement calculus for the language. The logic and refinement calculus are presented as natural deduction style proof rules that allow us to give formal proofs of language properties and provide the basis for a formal program development framework. The notion of refinement that is encoded by the refinement rules is also extensively investigated.

year: 2005

title: The happy story of small business financing

authors: Vos, Ed

subjects: small-to medium-sized enterprises (SMEs)

abstract: We examine two data sets, one from the UK (n = 15,750) and one from the US (n = 3239), to show that SME financial behaviour demonstrates substantial financial contentment, or ‘happiness’. We find fewer than 10% of the UK firms seek significant growth and only 1.32% of US firms list a shortage of capital other than working capital as a problem. Financial performance indicators (growth, return on assets, profit margin) were not found to be determinants of SME financing activities, as might be expected in a ‘rational’ risk–return environment. Younger and less educated SME owners more actively use external financing – even though more education reduces the fear of loan denial – while older and more educated (‘wiser’) SME owners are found to be being less likely to seek or use external financing. The contentment hypothesis for SME financing also extends to high-growth firms in that we show that they participate more in the loan markets than low-growth firms. By way of contrast to the finance gap hypothesis, the contentment hypothesis observes the importance of social networks (connections) [for finance] and confirms the ‘connections – happiness’ linkage in the literature on happiness while doubting the theoretical suitability of Jensen and Meckling [Jensen, M., Meckling, W., 1976. Theory of the firm: Managerial behavior, agency costs, and ownership structure. Journal of Financial Economics 3, 305–360.] base-case analysis for SMEs.

text: The happy story of small business financing We examine two data sets, one from the UK (n = 15,750) and one from the US (n = 3239), to show that SME financial behaviour demonstrates substantial financial contentment, or ‘happiness’. We find fewer than 10% of the UK firms seek significant growth and only 1.32% of US firms list a shortage of capital other than working capital as a problem. Financial performance indicators (growth, return on assets, profit margin) were not found to be determinants of SME financing activities, as might be expected in a ‘rational’ risk–return environment. Younger and less educated SME owners more actively use external financing – even though more education reduces the fear of loan denial – while older and more educated (‘wiser’) SME owners are found to be being less likely to seek or use external financing. The contentment hypothesis for SME financing also extends to high-growth firms in that we show that they participate more in the loan markets than low-growth firms. By way of contrast to the finance gap hypothesis, the contentment hypothesis observes the importance of social networks (connections) [for finance] and confirms the ‘connections – happiness’ linkage in the literature on happiness while doubting the theoretical suitability of Jensen and Meckling [Jensen, M., Meckling, W., 1976. Theory of the firm: Managerial behavior, agency costs, and ownership structure. Journal of Financial Economics 3, 305–360.] base-case analysis for SMEs.

year: 2007

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