title: Learning from batched data: model combination vs data combination

authors: Ting, Kai Ming

subjects: computer science

abstract: When presented with multiple batches of data, one can either combine them into a single batch before applying a machine learning procedure or learn from each batch independently and combine the resulting models. The former procedure, data combination, is straightforward; this paper investigates the latter, model combination. Given an appropriate combination method, one might expect model combination to prove superior when the data in each batch was obtained under somewhat different conditions or when different learning algorithms were used on the batches. Empirical results show that model combination often outperforms data combination even when the batches are drawn randomly from a single source of data and the same learning method is used on each. Moreover, this is not just an artifact of one particular method of combining models: it occurs with several different combination methods. 
We relate this phenomenon to the learning curve of the classifiers being used. Early in the learning process when the learning curve is steep there is much to gain from data combination, but later when it becomes shallow there is less to gain and model combination achieves a greater reduction in variance and hence a lower error rate.
The practical implication of these results is that one should consider using model combination rather than data combination, especially when multiple batches of data for the same task are readily available. It is often superior even when the batches are drawn randomly from a single sample, and we expect its advantage to increase if genuine statistical differences between the batches exist.

text: Learning from batched data: model combination vs data combination When presented with multiple batches of data, one can either combine them into a single batch before applying a machine learning procedure or learn from each batch independently and combine the resulting models. The former procedure, data combination, is straightforward; this paper investigates the latter, model combination. Given an appropriate combination method, one might expect model combination to prove superior when the data in each batch was obtained under somewhat different conditions or when different learning algorithms were used on the batches. Empirical results show that model combination often outperforms data combination even when the batches are drawn randomly from a single source of data and the same learning method is used on each. Moreover, this is not just an artifact of one particular method of combining models: it occurs with several different combination methods. 
We relate this phenomenon to the learning curve of the classifiers being used. Early in the learning process when the learning curve is steep there is much to gain from data combination, but later when it becomes shallow there is less to gain and model combination achieves a greater reduction in variance and hence a lower error rate.
The practical implication of these results is that one should consider using model combination rather than data combination, especially when multiple batches of data for the same task are readily available. It is often superior even when the batches are drawn randomly from a single sample, and we expect its advantage to increase if genuine statistical differences between the batches exist.

year: 1997-05

title: Interfacial modification of hemp fiber reinforced composites using fungal and alkali treatment

authors: Pickering, Kim L.

subjects: natural fibers

abstract: Increasing worldwide environmental awareness is encouraging scientific research into developing cheaper, more sustainable materials. Industrial hemp fiber is one of the strongest and stiffest available natural fibers [K. L. Pickering, M. Priest, T. Watts, G. Beckermann, and S. N. Alam, J. Adv. Mater. 37, 15 (2005)] and therefore has great potential in composite materials. Incorporated into a thermoplastic matrix, it gives a structural material that is cheap, lightweight, and recyclable. However, natural fibers are commonly incompatible with common molding thermoplastics such as polypropylene, which limits the performance of the composites produced. The main objective of the current work was to investigate the use of fungi to treat hemp fiber to create better bonding characteristics in natural fiber reinforced polypropylene composites. X-ray diffraction (XRD), ζ-potential, lignin testing, thermal analysis, and scanning electron microscopy (SEM) were used to characterize the effect of treatment on hemp fibers. A combined alkali and fungi treated fiber composite produced the highest tensile strength of 48.3 MPa, an increase of 32% compared to composites with untreated fiber.

text: Interfacial modification of hemp fiber reinforced composites using fungal and alkali treatment Increasing worldwide environmental awareness is encouraging scientific research into developing cheaper, more sustainable materials. Industrial hemp fiber is one of the strongest and stiffest available natural fibers [K. L. Pickering, M. Priest, T. Watts, G. Beckermann, and S. N. Alam, J. Adv. Mater. 37, 15 (2005)] and therefore has great potential in composite materials. Incorporated into a thermoplastic matrix, it gives a structural material that is cheap, lightweight, and recyclable. However, natural fibers are commonly incompatible with common molding thermoplastics such as polypropylene, which limits the performance of the composites produced. The main objective of the current work was to investigate the use of fungi to treat hemp fiber to create better bonding characteristics in natural fiber reinforced polypropylene composites. X-ray diffraction (XRD), ζ-potential, lignin testing, thermal analysis, and scanning electron microscopy (SEM) were used to characterize the effect of treatment on hemp fibers. A combined alkali and fungi treated fiber composite produced the highest tensile strength of 48.3 MPa, an increase of 32% compared to composites with untreated fiber.

year: 2007

title: Indigenising the Screen, Navigating the Currents of Change, a Vision of Fourth Cinema

authors: Bristowe, Joseph Curtis

subjects: Māori Knowledge

abstract: This thesis tests the hypothesis that it is possible to both decolonise and Indigenise the New Zealand cinema screen. Secondary research explores how those discourses that promoted roles and expectations for Māori within the New Zealand film industry were based principally upon historical colonial ideologies imposed by various means upon the native populous, and subsequently reproduced. It has been argued that these discourses of race, gender and religion have predominantly perpetuated negative belief systems about Māori, have contributed to the reproduction of stereotypical images of Māori, and that alternative structures of belief will be necessary in the field of cultural production. 
This thesis stems from this essential argument, and is fuelled by the researcher’s own desire to demystify, decolonise and Indigenise the New Zealand screen through the development of a Kaupapa Māori based strategic framework to inform/guide Māori scriptwriting/filmmaking practice. Drawing upon academic research, intimate cultural knowledge and the practice of creative writing, this thesis will explore the case that when thought and action are focused effectively through an applicable and practical Indigenous framework, an expression of collective identity based on individual qualities will deliver a better approach to Māori scriptwriting/filmmaking practice. This case will be developed and examined.

The case also depends on arguing that supposedly progressive representations of Māori in mainstream New Zealand films since the mid-1980s are not an incremental advance towards Fourth Cinema, because Māori subjectivity in film had still not been reconnected with a self-efficacy belief system based upon Indigenous foundations. The alternative approach effectively materialises strong anti-colonial perspectives aimed specifically at subverting long-held and dominant colonial discourses. Such an approach rejects the tradition of being defined, constructed and represented through discourses that serve to promote the interests of a majority and, in doing so, offers a collective vision for Fourth Cinema or Indigenous Cinema as advocated by the late Barry Barclay who campaigned for an Indigenous filmatic base grounded firmly in the philosophies, concepts and practices of the people. A tantalising larger question is whether specific strategic frameworks (e.g. in differing national contexts) tap into a common base of ‘Fourth Cinema’ values and philosophy, a base that then deeply affects all aspects of practice, from idea generation to narrative structures or the handling of time.

This thesis shall therefore be largely focused upon attempting to define and determine the foundations of an Indigenous knowledge system, and then upon how such definitions can revitalise those foundations for effective application in a contemporary context. Such an approach is founded upon the belief that what we are lacking in the Māori world is not the quantity of Māori knowledge; there is a veritable plethora of Māori knowledge still available. My research will seek to demonstrate that what is lacking is sufficient qualitatively powerful contemporary thought that yields ‘reflections’ contained in that knowledge, i.e., appropriate insight into their contemporary application.  This view is supported by the words of noted Māori Scholar Charles Royal (2002):

A key aspiration of all indigenous people is cultural survival. This means the perpetuation of our knowledge, our traditions, our worldviews, our philosophies. What this requires, however, is not so much the simple use of traditional knowledge but research into its principles, its fundamental view on reality and the creative application of those views in the contemporary context. Otherwise indigenous knowledge will remain merely historical phenomena, a museum curio bearing little relevance to the contemporary experience of indigenous peoples. (p. 11-12)

Importantly, I will examine the proposition that the more we discover, examine and utilise Māori knowledge, the more we will grow to understand new ways to create, design and fashion contemporary applications of this knowledge. Therefore, what is required and what should be of impetus to present day Māori scholars is a new spirit of enquiry, into the evolution of Indigenous knowledge systems and more specifically in this context, their role in relation to filmmaking processes. Such a belief is supported by the words of noted Ngāti Porou tohunga (expert in traditional lore) New Amsterdam Reedy (2011) who in relation to the application of Māori knowledge systems stated emphatically, ‘It’s not about how far back we can go, it’s about how far we can take it into the future.’ 

Such an approach is where I will argue the true revolutionary and emancipating thinking lies. Therefore, and of equally important significance, this thesis through the discussion of Māori knowledge and its contemporary application also engages debates surrounding the further development of Kaupapa Māori theory and more specifically, locates this within a filmmaking framework. In this way, Kaupapa Māori theory, as much as it is employed in this study is also subject to a self-reflective analysis and critique, therein providing an original contribution to the current literature in Kaupapa Māori theory and filmmaking and consequently developing a more comprehensive understanding of both fields of study.
For I will contend that Fourth Cinema is an effective way to understand the other, engage in new and integrated ways of thinking and living, and recognise how different bodies of knowledge, traditional or modern, Indigenous and Western may coexist for common purpose and mutual benefit. For this is the integrated and inclusive space where the complexity of the relationship between the colonial and post-colonial truly exists, one which brings together essential and non-essentialist post-colonial theoretical paradigms as well as Indigenous knowledge and contemporary Western knowledge systems thereby bridging worlds that, at first, seem to be strangers to one another, but may be more connected than they are different.

text: Indigenising the Screen, Navigating the Currents of Change, a Vision of Fourth Cinema This thesis tests the hypothesis that it is possible to both decolonise and Indigenise the New Zealand cinema screen. Secondary research explores how those discourses that promoted roles and expectations for Māori within the New Zealand film industry were based principally upon historical colonial ideologies imposed by various means upon the native populous, and subsequently reproduced. It has been argued that these discourses of race, gender and religion have predominantly perpetuated negative belief systems about Māori, have contributed to the reproduction of stereotypical images of Māori, and that alternative structures of belief will be necessary in the field of cultural production. 
This thesis stems from this essential argument, and is fuelled by the researcher’s own desire to demystify, decolonise and Indigenise the New Zealand screen through the development of a Kaupapa Māori based strategic framework to inform/guide Māori scriptwriting/filmmaking practice. Drawing upon academic research, intimate cultural knowledge and the practice of creative writing, this thesis will explore the case that when thought and action are focused effectively through an applicable and practical Indigenous framework, an expression of collective identity based on individual qualities will deliver a better approach to Māori scriptwriting/filmmaking practice. This case will be developed and examined.

The case also depends on arguing that supposedly progressive representations of Māori in mainstream New Zealand films since the mid-1980s are not an incremental advance towards Fourth Cinema, because Māori subjectivity in film had still not been reconnected with a self-efficacy belief system based upon Indigenous foundations. The alternative approach effectively materialises strong anti-colonial perspectives aimed specifically at subverting long-held and dominant colonial discourses. Such an approach rejects the tradition of being defined, constructed and represented through discourses that serve to promote the interests of a majority and, in doing so, offers a collective vision for Fourth Cinema or Indigenous Cinema as advocated by the late Barry Barclay who campaigned for an Indigenous filmatic base grounded firmly in the philosophies, concepts and practices of the people. A tantalising larger question is whether specific strategic frameworks (e.g. in differing national contexts) tap into a common base of ‘Fourth Cinema’ values and philosophy, a base that then deeply affects all aspects of practice, from idea generation to narrative structures or the handling of time.

This thesis shall therefore be largely focused upon attempting to define and determine the foundations of an Indigenous knowledge system, and then upon how such definitions can revitalise those foundations for effective application in a contemporary context. Such an approach is founded upon the belief that what we are lacking in the Māori world is not the quantity of Māori knowledge; there is a veritable plethora of Māori knowledge still available. My research will seek to demonstrate that what is lacking is sufficient qualitatively powerful contemporary thought that yields ‘reflections’ contained in that knowledge, i.e., appropriate insight into their contemporary application.  This view is supported by the words of noted Māori Scholar Charles Royal (2002):

A key aspiration of all indigenous people is cultural survival. This means the perpetuation of our knowledge, our traditions, our worldviews, our philosophies. What this requires, however, is not so much the simple use of traditional knowledge but research into its principles, its fundamental view on reality and the creative application of those views in the contemporary context. Otherwise indigenous knowledge will remain merely historical phenomena, a museum curio bearing little relevance to the contemporary experience of indigenous peoples. (p. 11-12)

Importantly, I will examine the proposition that the more we discover, examine and utilise Māori knowledge, the more we will grow to understand new ways to create, design and fashion contemporary applications of this knowledge. Therefore, what is required and what should be of impetus to present day Māori scholars is a new spirit of enquiry, into the evolution of Indigenous knowledge systems and more specifically in this context, their role in relation to filmmaking processes. Such a belief is supported by the words of noted Ngāti Porou tohunga (expert in traditional lore) New Amsterdam Reedy (2011) who in relation to the application of Māori knowledge systems stated emphatically, ‘It’s not about how far back we can go, it’s about how far we can take it into the future.’ 

Such an approach is where I will argue the true revolutionary and emancipating thinking lies. Therefore, and of equally important significance, this thesis through the discussion of Māori knowledge and its contemporary application also engages debates surrounding the further development of Kaupapa Māori theory and more specifically, locates this within a filmmaking framework. In this way, Kaupapa Māori theory, as much as it is employed in this study is also subject to a self-reflective analysis and critique, therein providing an original contribution to the current literature in Kaupapa Māori theory and filmmaking and consequently developing a more comprehensive understanding of both fields of study.
For I will contend that Fourth Cinema is an effective way to understand the other, engage in new and integrated ways of thinking and living, and recognise how different bodies of knowledge, traditional or modern, Indigenous and Western may coexist for common purpose and mutual benefit. For this is the integrated and inclusive space where the complexity of the relationship between the colonial and post-colonial truly exists, one which brings together essential and non-essentialist post-colonial theoretical paradigms as well as Indigenous knowledge and contemporary Western knowledge systems thereby bridging worlds that, at first, seem to be strangers to one another, but may be more connected than they are different.

year: 2017