title: Static techniques for reducing memory usage in the C implementation of Whiley programs

authors: Weng, Min-Hsien

subjects: Computer science

abstract: Languages that use call-by-value semantics, such as Whiley, can make program verification easier. But effcient implementation becomes harder, due to the overhead of copying and garbage collection. This paper describes how a mixture of static analysis and runtime-monitoring can be used to eliminate unnecessary copying and deallocate memory with- out garbage collection. We show that this allows Whiley programs to be translated into effcient C implementations.

text: Static techniques for reducing memory usage in the C implementation of Whiley programs Languages that use call-by-value semantics, such as Whiley, can make program verification easier. But effcient implementation becomes harder, due to the overhead of copying and garbage collection. This paper describes how a mixture of static analysis and runtime-monitoring can be used to eliminate unnecessary copying and deallocate memory with- out garbage collection. We show that this allows Whiley programs to be translated into effcient C implementations.

year: 2017

title: A framework for compositional nonblocking verification of extended finite-state machines

authors: Mohajerani, Sahar

subjects: Science & Technology

abstract: This paper presents a framework for compositional nonblocking verification of discrete event systems modelled as extended finite-state machines (EFSM). Previous results are improved to consider general conflict-equivalence based abstractions of EFSMs communicating both via shared variables and events. Performance issues resulting from the conversion of EFSM systems to finite-state machine systems are avoided by operating directly on EFSMs, deferring the unfolding of variables into state machines as long as possible. Several additional methods to abstract EFSMs and remove events are also presented. The proposed algorithm has been implemented in the discrete event systems tool Supremica, and the paper presents experimental results for several large EFSM models that can be verified faster than by previously used methods.

text: A framework for compositional nonblocking verification of extended finite-state machines This paper presents a framework for compositional nonblocking verification of discrete event systems modelled as extended finite-state machines (EFSM). Previous results are improved to consider general conflict-equivalence based abstractions of EFSMs communicating both via shared variables and events. Performance issues resulting from the conversion of EFSM systems to finite-state machine systems are avoided by operating directly on EFSMs, deferring the unfolding of variables into state machines as long as possible. Several additional methods to abstract EFSMs and remove events are also presented. The proposed algorithm has been implemented in the discrete event systems tool Supremica, and the paper presents experimental results for several large EFSM models that can be verified faster than by previously used methods.

year: 2016-03-01

title: Engaging the parent/whānau community: Methods, benefits, and challenges for senior leaders in small town and rural New Zealand secondary schools

authors: Kallahar, David

abstract: Engaging parents and whānau (family) in a respectful partnership that develops strong home-school connections and uses effective methods of engagement has the potential to positively affect student outcomes. However, there are also methods of engagement that can be counterproductive and negatively affect student outcomes. This study presents how senior leaders in small town and rural secondary schools in New Zealand are engaging with their parent and whānau community. The investigation reveals what methods they are using to engage parents and whānau and, how effective they and a small number of parents and whānau consider these are, then outlines some of the benefits and challenges that they face in this process. 
The literature reviewed for this study emphasised the benefits of engagement between parents, whānau and school leaders, along with the essential ingredients necessary for successful home-school partnerships and how senior leaders play a critical role in developing the conditions for schools’ engagement with their parent and whānau community. The consideration of aspects from New Zealand’s political and educational history illuminated possible reasons why parents and whānau of Māori descent struggle to connect with schools, and how concepts which have traditionally guided the way of life for these indigenous people can be and are being used by school leaders to develop strong, respectful enduring partnerships. Research on the rural context and how schools in this type of location manage engagement was also studied and seen as yet another factor that senior leaders need to bear in mind when planning for engagement. Examination of three types of engagement – involvement, empowerment, and solidarity, revealed that each is characterised by certain practices and represent a progression in the level of contribution and commitment parents and whānau give to the school. Engagement and progression are, however, dependent on how connected parents and whānau are to their child’s school and how much of a sense of belonging they have.
The study was conducted using an interpretive paradigm to afford richer more detailed descriptions to be gathered from both the senior leaders at three small town and rural schools, and some of the parent and whānau community of each of these schools. A mixed-methods approach was taken to gather and triangulate both qualitative and quantitative data. Qualitative data collected and analysed included semi-structured interviews with senior leaders, descriptive survey submissions from parents and whānau, along with planning and review documents for each school. Quantitative data derived from parents and whānau surveys and represents their preferred methods of engagement with the school statistically.
The study findings indicate that the schools use a range of methods to engage parents and whānau. These include face to face interactions and time-efficient digital communication systems. Some such as an open door policy and parent conferences were reported as effective by leaders and whānau. Furthermore, it was found that there is no one way to engage with all parents and whānau, some liked to participate in events and activities and derived a sense of belonging from this while others simply preferred to gather information and not engage with the school beyond this need. 
Partnerships between parents, whānau and school leaders that were built on respectful relationships and the acknowledgement of difference were said to lead to stronger connections and more productive working relationships, by the senior leaders in all of the schools in the study. These could be said to reflect the use of guiding concepts for living in partnership used by Māori, which the schools in this study were using as foundations in building and sustaining the partnerships with their parents and whānau. The three types of engagement, structured in a progressive framework, also illustrated to school leaders where their parent and whānau community were situated and where they as leaders needed to work further to strengthen and secure both the partnership and to increase engagement.   
Further research as a result of this study could relate to gaining a better understanding of why specific methods of engagement are more acceptable to parents and whānau than others. It could involve looking at the delivery of these methods by senior leaders in more detail, and trialling the three-stage framework on a larger scale and in different contexts, particularly in urban areas where school roll numbers are higher, and communities are less connected.

text: Engaging the parent/whānau community: Methods, benefits, and challenges for senior leaders in small town and rural New Zealand secondary schools Engaging parents and whānau (family) in a respectful partnership that develops strong home-school connections and uses effective methods of engagement has the potential to positively affect student outcomes. However, there are also methods of engagement that can be counterproductive and negatively affect student outcomes. This study presents how senior leaders in small town and rural secondary schools in New Zealand are engaging with their parent and whānau community. The investigation reveals what methods they are using to engage parents and whānau and, how effective they and a small number of parents and whānau consider these are, then outlines some of the benefits and challenges that they face in this process. 
The literature reviewed for this study emphasised the benefits of engagement between parents, whānau and school leaders, along with the essential ingredients necessary for successful home-school partnerships and how senior leaders play a critical role in developing the conditions for schools’ engagement with their parent and whānau community. The consideration of aspects from New Zealand’s political and educational history illuminated possible reasons why parents and whānau of Māori descent struggle to connect with schools, and how concepts which have traditionally guided the way of life for these indigenous people can be and are being used by school leaders to develop strong, respectful enduring partnerships. Research on the rural context and how schools in this type of location manage engagement was also studied and seen as yet another factor that senior leaders need to bear in mind when planning for engagement. Examination of three types of engagement – involvement, empowerment, and solidarity, revealed that each is characterised by certain practices and represent a progression in the level of contribution and commitment parents and whānau give to the school. Engagement and progression are, however, dependent on how connected parents and whānau are to their child’s school and how much of a sense of belonging they have.
The study was conducted using an interpretive paradigm to afford richer more detailed descriptions to be gathered from both the senior leaders at three small town and rural schools, and some of the parent and whānau community of each of these schools. A mixed-methods approach was taken to gather and triangulate both qualitative and quantitative data. Qualitative data collected and analysed included semi-structured interviews with senior leaders, descriptive survey submissions from parents and whānau, along with planning and review documents for each school. Quantitative data derived from parents and whānau surveys and represents their preferred methods of engagement with the school statistically.
The study findings indicate that the schools use a range of methods to engage parents and whānau. These include face to face interactions and time-efficient digital communication systems. Some such as an open door policy and parent conferences were reported as effective by leaders and whānau. Furthermore, it was found that there is no one way to engage with all parents and whānau, some liked to participate in events and activities and derived a sense of belonging from this while others simply preferred to gather information and not engage with the school beyond this need. 
Partnerships between parents, whānau and school leaders that were built on respectful relationships and the acknowledgement of difference were said to lead to stronger connections and more productive working relationships, by the senior leaders in all of the schools in the study. These could be said to reflect the use of guiding concepts for living in partnership used by Māori, which the schools in this study were using as foundations in building and sustaining the partnerships with their parents and whānau. The three types of engagement, structured in a progressive framework, also illustrated to school leaders where their parent and whānau community were situated and where they as leaders needed to work further to strengthen and secure both the partnership and to increase engagement.   
Further research as a result of this study could relate to gaining a better understanding of why specific methods of engagement are more acceptable to parents and whānau than others. It could involve looking at the delivery of these methods by senior leaders in more detail, and trialling the three-stage framework on a larger scale and in different contexts, particularly in urban areas where school roll numbers are higher, and communities are less connected.

year: 2020