title: Ensembles of balanced nested dichotomies for multi-class problems

authors: Dong, Lin

subjects: Science & Technology

abstract: A system of nested dichotomies is a hierarchical decomposition of a multi-class problem with c classes into c−1 two-class problems and can be represented as a tree structure. Ensembles of randomly generated nested dichotomies have proven to be an effective approach to multi-class learning problems [1]. However, sampling trees by giving each tree equal probability means that the depth of a tree is limited only by the number of classes, and very unbalanced trees can negatively affect runtime.

In this paper, we investigate two approaches to building balanced nested dichotomies—class-balanced nested dichotomies and data-balanced nested dichotomies—and evaluate them in the same ensemble setting. Using C4.5 decision trees as the base models, we show that both approaches can reduce runtime with little or no effect on accuracy, especially on problems with many classes. We also investigate the effect of caching models when building ensembles of nested dichotomies.

text: Ensembles of balanced nested dichotomies for multi-class problems A system of nested dichotomies is a hierarchical decomposition of a multi-class problem with c classes into c−1 two-class problems and can be represented as a tree structure. Ensembles of randomly generated nested dichotomies have proven to be an effective approach to multi-class learning problems [1]. However, sampling trees by giving each tree equal probability means that the depth of a tree is limited only by the number of classes, and very unbalanced trees can negatively affect runtime.

In this paper, we investigate two approaches to building balanced nested dichotomies—class-balanced nested dichotomies and data-balanced nested dichotomies—and evaluate them in the same ensemble setting. Using C4.5 decision trees as the base models, we show that both approaches can reduce runtime with little or no effect on accuracy, especially on problems with many classes. We also investigate the effect of caching models when building ensembles of nested dichotomies.

year: 2005-01-01

title: Terrorism, war and international law: the legality of the use of force against Afghanistan in 2001

authors: Williamson, Myra Elsie Jane Bell

subjects: United Nations' Security Council

abstract: The thesis examines the international law pertaining to the use of force by states, in general, and to the use of force in self-defence, in particular.  The main question addressed is whether the use of force, which was purported to be in self-defence, by the United States, the United Kingdom and their allies against al Qaeda, the Taliban and Afghanistan, beginning on 7 October 2001, was lawful.  

The thesis focuses not only on this specific use of force, but also on the changing nature of conflict, the definition of terrorism and on the historical evolution of limitations on the use of force, from antiquity until 2006.  In the six chapters which trace the epochs of international law, the progression of five inter-related concepts is followed: limitations on the resort to force generally, the use of force in self-defence, pre-emptive self-defence, the use of forcible measures short of war, and the use of force in response to non-state actors.

This historical analysis includes a particular emphasis on understanding the meaning of the 'inherent right of self-defence', which was preserved by Article 51 of the United Nations' Charter.  This analysis is then applied to the use of force against Afghanistan which occurred in 2001.  Following the terrorist attacks of 11 September, the US and the UK notified the United Nations Security Council of their resort to force in self-defence under Article 51.  Each element of Article 51 is analysed and the thesis concludes that there are significant doubts as to the lawfulness of that decision to employ force.  In addition to the self-defence justification, other possible grounds for intervention are also examined, such as humanitarian intervention, Security Council authorisation and intervention by invitation.

This thesis challenges the common assumption that the use of force against Afghanistan was an example of states exercising their inherent right to self-defence.  It argues that if this particular use of force is not challenged, it will lead to an expansion of the right of self-defence which will hinder rather than enhance international peace and security.  Finally, this thesis draws on recent examples to illustrate the point that the use of force against Afghanistan could become a dangerous precedent for the use of force in self-defence.

text: Terrorism, war and international law: the legality of the use of force against Afghanistan in 2001 The thesis examines the international law pertaining to the use of force by states, in general, and to the use of force in self-defence, in particular.  The main question addressed is whether the use of force, which was purported to be in self-defence, by the United States, the United Kingdom and their allies against al Qaeda, the Taliban and Afghanistan, beginning on 7 October 2001, was lawful.  

The thesis focuses not only on this specific use of force, but also on the changing nature of conflict, the definition of terrorism and on the historical evolution of limitations on the use of force, from antiquity until 2006.  In the six chapters which trace the epochs of international law, the progression of five inter-related concepts is followed: limitations on the resort to force generally, the use of force in self-defence, pre-emptive self-defence, the use of forcible measures short of war, and the use of force in response to non-state actors.

This historical analysis includes a particular emphasis on understanding the meaning of the 'inherent right of self-defence', which was preserved by Article 51 of the United Nations' Charter.  This analysis is then applied to the use of force against Afghanistan which occurred in 2001.  Following the terrorist attacks of 11 September, the US and the UK notified the United Nations Security Council of their resort to force in self-defence under Article 51.  Each element of Article 51 is analysed and the thesis concludes that there are significant doubts as to the lawfulness of that decision to employ force.  In addition to the self-defence justification, other possible grounds for intervention are also examined, such as humanitarian intervention, Security Council authorisation and intervention by invitation.

This thesis challenges the common assumption that the use of force against Afghanistan was an example of states exercising their inherent right to self-defence.  It argues that if this particular use of force is not challenged, it will lead to an expansion of the right of self-defence which will hinder rather than enhance international peace and security.  Finally, this thesis draws on recent examples to illustrate the point that the use of force against Afghanistan could become a dangerous precedent for the use of force in self-defence.

year: 2007

title: 'Kōrero Tuku Iho': Reconfiguring Oral History and Oral Tradition

authors: Mahuika, Nepia

subjects: History

abstract: The studies of oral history and oral tradition each have their own distinctive bodies of literature and preferred methodologies, yet share significant overlaps that make them difficult to differentiate. For many indigenous peoples, oral histories and traditions are key to their their past, present, and future lives, and are rarely considered separate. This thesis examines the differences and similarities between the studies of oral history and oral tradition. It explores how these areas of research converge and diverge in form, politics, practice, and theory, and the extent to which they resonate within a specific ‘indigenous’ context and community.
The thesis draws on the life narrative interviews of four generations of Ngāti Porou descendents, the second largest tribal group in New Zealand, whose home boundaries extend from Potikirua in the north to Te Toka-a-Taiau in the south on the East Coast of the North Island. Drawing on these voices, this study offers a commentary on the form and nature of oral traditions and histories from an indigenous perspective, and explores the ways they converge and depart from ‘international’ understandings. An exploration of these intersections offers insights to the ways oral history and oral traditions might be reconsidered as distinctive fields of study. Reconfigured through an indigenous frame of reference, this thesis challenges scholars of both oral history and oral tradition to expand their conceptions. Likewise, it urges indigenous scholars to consider more deeply the work of oral historians and oral traditionalists to further enhance their scholarship. Moreover, this thesis revisits the intellectual and conceptual territory that names and claims oral history and oral tradition, and invites all those who work in these areas to develop a more extensive comprehension of the interconnections that exist between each area of study.

text: 'Kōrero Tuku Iho': Reconfiguring Oral History and Oral Tradition The studies of oral history and oral tradition each have their own distinctive bodies of literature and preferred methodologies, yet share significant overlaps that make them difficult to differentiate. For many indigenous peoples, oral histories and traditions are key to their their past, present, and future lives, and are rarely considered separate. This thesis examines the differences and similarities between the studies of oral history and oral tradition. It explores how these areas of research converge and diverge in form, politics, practice, and theory, and the extent to which they resonate within a specific ‘indigenous’ context and community.
The thesis draws on the life narrative interviews of four generations of Ngāti Porou descendents, the second largest tribal group in New Zealand, whose home boundaries extend from Potikirua in the north to Te Toka-a-Taiau in the south on the East Coast of the North Island. Drawing on these voices, this study offers a commentary on the form and nature of oral traditions and histories from an indigenous perspective, and explores the ways they converge and depart from ‘international’ understandings. An exploration of these intersections offers insights to the ways oral history and oral traditions might be reconsidered as distinctive fields of study. Reconfigured through an indigenous frame of reference, this thesis challenges scholars of both oral history and oral tradition to expand their conceptions. Likewise, it urges indigenous scholars to consider more deeply the work of oral historians and oral traditionalists to further enhance their scholarship. Moreover, this thesis revisits the intellectual and conceptual territory that names and claims oral history and oral tradition, and invites all those who work in these areas to develop a more extensive comprehension of the interconnections that exist between each area of study.

year: 2012