title: Contexts, refinement and determinism

authors: Reeves, Steve

subjects: computer science

abstract: In this paper we have been influenced by those who take an “engineering view” of the problem of designing systems, i.e. a view that is motivated by what someone designing a real system will be concerned with, and what questions will arise as they work on their design. Specifically, we have borrowed from the testing work of Hennessy, de Nicola and van Glabbeek, e.g. [13, 5, 21, 40, 39].
Here we concentrate on one fundamental part of the engineering view and where consideration of it leads. The aspects we are concerned with are computational entities in contexts, observed by users. This leads to formalising design steps that are often left informal, and that in turn gives insights into non-determinism and ultimately leads to being able to use refinement in situations where existing techniques fail.

text: Contexts, refinement and determinism In this paper we have been influenced by those who take an “engineering view” of the problem of designing systems, i.e. a view that is motivated by what someone designing a real system will be concerned with, and what questions will arise as they work on their design. Specifically, we have borrowed from the testing work of Hennessy, de Nicola and van Glabbeek, e.g. [13, 5, 21, 40, 39].
Here we concentrate on one fundamental part of the engineering view and where consideration of it leads. The aspects we are concerned with are computational entities in contexts, observed by users. This leads to formalising design steps that are often left informal, and that in turn gives insights into non-determinism and ultimately leads to being able to use refinement in situations where existing techniques fail.

year: 2010

title: Optimizing the induction of alternating decision trees

authors: Pfahringer, Bernhard

subjects: computer science

abstract: The alternating decision tree brings comprehensibility to the performance enhancing capabilities of boosting. A single interpretable tree is induced wherein knowledge is distributed across the nodes and multiple paths are traversed to form predictions. The complexity of the algorithm is quadratic in the number of boosting iterations and this makes it unsuitable for larger knowledge discovery in database tasks. In this paper we explore various heuristic methods for reducing this complexity while maintaining the performance characteristics of the original algorithm. In experiments using standard, artificial and knowledge discovery datasets we show that a range of heuristic methods with log linear complexity are capable of achieving similar performance to the original method. Of these methods, the random walk heuristic is seen to out-perform all others as the number of boosting iterations increases. The average case complexity of this method is linear.

text: Optimizing the induction of alternating decision trees The alternating decision tree brings comprehensibility to the performance enhancing capabilities of boosting. A single interpretable tree is induced wherein knowledge is distributed across the nodes and multiple paths are traversed to form predictions. The complexity of the algorithm is quadratic in the number of boosting iterations and this makes it unsuitable for larger knowledge discovery in database tasks. In this paper we explore various heuristic methods for reducing this complexity while maintaining the performance characteristics of the original algorithm. In experiments using standard, artificial and knowledge discovery datasets we show that a range of heuristic methods with log linear complexity are capable of achieving similar performance to the original method. Of these methods, the random walk heuristic is seen to out-perform all others as the number of boosting iterations increases. The average case complexity of this method is linear.

year: 2001

title: Digital Taniwha: Growing Māori participation in the IT industry

authors: Williams, Warren

subjects: Māori research

abstract: This study explores the influencing factors on the participation levels of Māori (indigenous people of New Zealand) in the national IT industry. It particularly focusses on Māori IT professionals and why their participation in IT sector events and activities are not as visible as non-Māori. The researcher, who is also a Māori IT professional, has engaged with Māori in IT during his career, and forms the initial question of “where are they?”. The researcher proposes that more IT entrants and current IT professionals, who hold a Māori worldview grounded in cultural values that promote innovation and creativity, would benefit not only Māori but the IT industry and the nation. 

This thesis employs qualitative aligned research approaches - Kaupapa Māori and Wayfinding, to enable culturally appropriate methods during the data collection and analysis stages. It uses these approaches to support the inclusion of key cultural tenets such as Te Reo Māori (Māori language) and Māori values and practice. This research introduces the term “digital kaitiaki” to appropriately refer to Māori IT professionals. It collects data using appreciative inquiry and action research approaches and specific methods from semi-structured interviews held with digital kaitiaki; through focus groups with over 70 people; and records from action committees and working groups; to field observations of over 30 people. 

It examines the fieldwork data using thematic analysis and cross-checks the themes against influencing factors from the participant’s (including his own) personal and professional careers. The analysis identifies the following key themes: Māori identity and culture, feelings of personal and cultural responsibility, motivational forces, and role models. To respond to these, the study proposes a “Waka Kaitiaki Matihiko” model that connects with widely known Māori metaphors and symbols. It deploys these to inform and capture existing and potential future processes involving digital kaitiaki and to suggest how a culturally supported vehicle for Māori worldview engagement could encourage more Māori to enter IT and lend support for leadership roles for existing Māori IT workers.

To realise that potential, the study looks at leadership styles of the past to recognise what leadership is needed to increase contemporary Māori participation in the IT sector. It compares and contrasts leadership styles over time and constructs a new “digital taniwha” leadership style as fit for purpose for the challenge of growing Māori participation and for steering more Māori into leadership roles. Finally, by building on categories in the Blue Ocean Leadership grid and interweaving them with elements from existing Māori leadership literature, metaphors and symbols, and the findings from participants, it recommends a series of action-oriented interventions. These are designed to address the challenges identified in the key themes and feature governance and leadership programmes, as well as talent and career pathways, Te Reo Māori digital projects, tuakana/teina support and mentoring models, research into diversity representation (e.g., women and youth), and models designed to provide space to support the interventions proposed.

text: Digital Taniwha: Growing Māori participation in the IT industry This study explores the influencing factors on the participation levels of Māori (indigenous people of New Zealand) in the national IT industry. It particularly focusses on Māori IT professionals and why their participation in IT sector events and activities are not as visible as non-Māori. The researcher, who is also a Māori IT professional, has engaged with Māori in IT during his career, and forms the initial question of “where are they?”. The researcher proposes that more IT entrants and current IT professionals, who hold a Māori worldview grounded in cultural values that promote innovation and creativity, would benefit not only Māori but the IT industry and the nation. 

This thesis employs qualitative aligned research approaches - Kaupapa Māori and Wayfinding, to enable culturally appropriate methods during the data collection and analysis stages. It uses these approaches to support the inclusion of key cultural tenets such as Te Reo Māori (Māori language) and Māori values and practice. This research introduces the term “digital kaitiaki” to appropriately refer to Māori IT professionals. It collects data using appreciative inquiry and action research approaches and specific methods from semi-structured interviews held with digital kaitiaki; through focus groups with over 70 people; and records from action committees and working groups; to field observations of over 30 people. 

It examines the fieldwork data using thematic analysis and cross-checks the themes against influencing factors from the participant’s (including his own) personal and professional careers. The analysis identifies the following key themes: Māori identity and culture, feelings of personal and cultural responsibility, motivational forces, and role models. To respond to these, the study proposes a “Waka Kaitiaki Matihiko” model that connects with widely known Māori metaphors and symbols. It deploys these to inform and capture existing and potential future processes involving digital kaitiaki and to suggest how a culturally supported vehicle for Māori worldview engagement could encourage more Māori to enter IT and lend support for leadership roles for existing Māori IT workers.

To realise that potential, the study looks at leadership styles of the past to recognise what leadership is needed to increase contemporary Māori participation in the IT sector. It compares and contrasts leadership styles over time and constructs a new “digital taniwha” leadership style as fit for purpose for the challenge of growing Māori participation and for steering more Māori into leadership roles. Finally, by building on categories in the Blue Ocean Leadership grid and interweaving them with elements from existing Māori leadership literature, metaphors and symbols, and the findings from participants, it recommends a series of action-oriented interventions. These are designed to address the challenges identified in the key themes and feature governance and leadership programmes, as well as talent and career pathways, Te Reo Māori digital projects, tuakana/teina support and mentoring models, research into diversity representation (e.g., women and youth), and models designed to provide space to support the interventions proposed.

year: 2020