title: Naïve Bayes for text classification with unbalanced classes

authors: Frank, Eibe

subjects: computer science

abstract: Multinomial naive Bayes (MNB) is a popular method for document classification due to its computational efficiency and relatively good predictive performance. It has recently been established that predictive performance can be improved further by appropriate data transformations [1,2]. In this paper we present another transformation that is designed to combat a potential problem with the application of MNB to unbalanced datasets. We propose an appropriate correction by adjusting attribute priors. This correction can be implemented as another data normalization step, and we show that it can significantly improve the area under the ROC curve. We also show that the modified version of MNB is very closely related to the simple centroid-based classifier and compare the two methods empirically.

text: Naïve Bayes for text classification with unbalanced classes Multinomial naive Bayes (MNB) is a popular method for document classification due to its computational efficiency and relatively good predictive performance. It has recently been established that predictive performance can be improved further by appropriate data transformations [1,2]. In this paper we present another transformation that is designed to combat a potential problem with the application of MNB to unbalanced datasets. We propose an appropriate correction by adjusting attribute priors. This correction can be implemented as another data normalization step, and we show that it can significantly improve the area under the ROC curve. We also show that the modified version of MNB is very closely related to the simple centroid-based classifier and compare the two methods empirically.

year: 2006

title: Defining a US defence diplomacy for Brazil at the beginning of the century

authors: Zirker, Daniel

subjects: diplomacy

abstract: At the beginning of the 1990s, the US military was apparently considered to be a significant threat by the Brazilian Armed Forces. Other military establishments in the Hemisphere likewise expressed a lack of confidence, and even a sense of fear, regarding the North Americans. After an ‘opening’ in military relations between Brazil and the United States, directed by General Barry McAfree, commander-in-chief of the US Southern Command (SOUTHCOM) in the mid 1990s, Brazilian military sentiment regarding the US marginally improved. Nevertheless, by the end of the 1990s and the beginning of this Century, the Brazilian Armed Forces again felt threatened by the unilateralism of the US military.
This work examines the the concept of ‘defense diplomacy’ and the process by which the Clinton Administration initiated an experiment in conjunction with the National Defense University (Fort Leslie McNair, Washington, DC), at the request of the Deputy Assitant Secretary of Defense for Western Hemisphere Affairs, that established between 1999 and 2001 a broader understanding of possible US defense diplomacy for the subsequent seven years. I was an invited participant in this experiment, along with more than two dozen North American and Latin American academics, including Brazilians, the aim of which was to complete a proposal under contract with the Defense Department. Although it was ended soon after the Bush Administration began, this experiment, and the broader concept of ‘defense diplomacy,’ may well have represented an important option for future hemispheric military relations.

text: Defining a US defence diplomacy for Brazil at the beginning of the century At the beginning of the 1990s, the US military was apparently considered to be a significant threat by the Brazilian Armed Forces. Other military establishments in the Hemisphere likewise expressed a lack of confidence, and even a sense of fear, regarding the North Americans. After an ‘opening’ in military relations between Brazil and the United States, directed by General Barry McAfree, commander-in-chief of the US Southern Command (SOUTHCOM) in the mid 1990s, Brazilian military sentiment regarding the US marginally improved. Nevertheless, by the end of the 1990s and the beginning of this Century, the Brazilian Armed Forces again felt threatened by the unilateralism of the US military.
This work examines the the concept of ‘defense diplomacy’ and the process by which the Clinton Administration initiated an experiment in conjunction with the National Defense University (Fort Leslie McNair, Washington, DC), at the request of the Deputy Assitant Secretary of Defense for Western Hemisphere Affairs, that established between 1999 and 2001 a broader understanding of possible US defense diplomacy for the subsequent seven years. I was an invited participant in this experiment, along with more than two dozen North American and Latin American academics, including Brazilians, the aim of which was to complete a proposal under contract with the Defense Department. Although it was ended soon after the Bush Administration began, this experiment, and the broader concept of ‘defense diplomacy,’ may well have represented an important option for future hemispheric military relations.

year: 2009

title: Harakeke (Phormium tenax) ecology and historical management by Maori: The changing landscape in New Zealand

authors: Wehi, Priscilla M.

subjects: ethnobotany

abstract: Harakeke (Phormium tenax: Phormiaceae) is an important weaving resource for the indigenous Maori people of New Zealand. This research project investigates Maori knowledge of harakeke ecology and management practices prior to the early 20th century within the context of a study of relevant environmental parameters that limit its natural distribution. Ecological information referring to harakeke was analysed from interviews with elders and ancestral sayings (whakatauki). As well, documents from the late 181h to the early 20th century were examined, and environmental parameters for both harakeke and wharariki (Phormium cookianum) were quantified and analysed using correlative models. 
Interviews with 11 elders (from Waikato and Northland) identified key issues in harakeke management, including 'correct' harvesting procedures, use of natural harakeke stands, and specific use of different varieties. Planting practices varied regionally. Three different methods of excess harakeke disposal were reported, including burning. The 15 whakatauki analysed emphasise the interconnectedness of ecosystems, including pollinator-plant relationships for kaka and bellbirds. Four whakataukirefer to environmental tolerances for harakeke and two to the use of fire to stimulate harakeke growth. Others refer to competition between shoots, nutrient requirements, and the growth and multiplication of harakeke offsets. 
Numerous early reports indicate that harakeke has been cultivated throughout much of New Zealand, with cultivations ranging in size from a few bushes to at least several acres. Thirty six varieties were linked to specific weaving uses. Twenty varieties were cultivated, but ten prized fibre varieties were also harvested from natural stands. Numbers of recorded varieties varied between districts, with 31 recorded in Taranaki but only two recorded by name for Northland. Valued varieties, including raumoa and oue, were dispersed throughout the North Island. Mapping different varieties revealed a wide spatial spread for varieties such as rataroa and oue. Specific management techniques included seed germination as well as vegetative propagation. Early records of harakeke pests were not found. Records of harakeke irrigation and the use of fire indicate that Maori created suitable conditions for new cultivations or pii harakeke, which may also have prevented insect infestation. Cumulatively, there is evidence of extensive active management of harakeke. Wharariki and harakeke were found to have distinct environmental niches, with wharariki better able to withstand cooler temperatures, higher rainfall and greater frequency of ground frost than harakeke.
Predictive mapping of harakeke for the northern region of New Zealand shows a low probability of naturally occurring harakeke in much of the Northland and Waikato interior, and a high probability in coastal areas with warm temperatures. It seems likely that Maori transported harakeke into areas where it was unlikely to have occurred naturally and that some apparently 'natural' stands ofharakeke were created and maintained by Maori.
Maori cultivation, dispersal and active management of harakeke, as well as possible creation of wetland areas, emphasises the importance of harakeke as an economic resource prior to European colonisation, and indicates how the New Zealand landscape may have been transformed. Maori ecological knowledge can contribute new perspectives to restoration ecology and ecosystem research.

text: Harakeke (Phormium tenax) ecology and historical management by Maori: The changing landscape in New Zealand Harakeke (Phormium tenax: Phormiaceae) is an important weaving resource for the indigenous Maori people of New Zealand. This research project investigates Maori knowledge of harakeke ecology and management practices prior to the early 20th century within the context of a study of relevant environmental parameters that limit its natural distribution. Ecological information referring to harakeke was analysed from interviews with elders and ancestral sayings (whakatauki). As well, documents from the late 181h to the early 20th century were examined, and environmental parameters for both harakeke and wharariki (Phormium cookianum) were quantified and analysed using correlative models. 
Interviews with 11 elders (from Waikato and Northland) identified key issues in harakeke management, including 'correct' harvesting procedures, use of natural harakeke stands, and specific use of different varieties. Planting practices varied regionally. Three different methods of excess harakeke disposal were reported, including burning. The 15 whakatauki analysed emphasise the interconnectedness of ecosystems, including pollinator-plant relationships for kaka and bellbirds. Four whakataukirefer to environmental tolerances for harakeke and two to the use of fire to stimulate harakeke growth. Others refer to competition between shoots, nutrient requirements, and the growth and multiplication of harakeke offsets. 
Numerous early reports indicate that harakeke has been cultivated throughout much of New Zealand, with cultivations ranging in size from a few bushes to at least several acres. Thirty six varieties were linked to specific weaving uses. Twenty varieties were cultivated, but ten prized fibre varieties were also harvested from natural stands. Numbers of recorded varieties varied between districts, with 31 recorded in Taranaki but only two recorded by name for Northland. Valued varieties, including raumoa and oue, were dispersed throughout the North Island. Mapping different varieties revealed a wide spatial spread for varieties such as rataroa and oue. Specific management techniques included seed germination as well as vegetative propagation. Early records of harakeke pests were not found. Records of harakeke irrigation and the use of fire indicate that Maori created suitable conditions for new cultivations or pii harakeke, which may also have prevented insect infestation. Cumulatively, there is evidence of extensive active management of harakeke. Wharariki and harakeke were found to have distinct environmental niches, with wharariki better able to withstand cooler temperatures, higher rainfall and greater frequency of ground frost than harakeke.
Predictive mapping of harakeke for the northern region of New Zealand shows a low probability of naturally occurring harakeke in much of the Northland and Waikato interior, and a high probability in coastal areas with warm temperatures. It seems likely that Maori transported harakeke into areas where it was unlikely to have occurred naturally and that some apparently 'natural' stands ofharakeke were created and maintained by Maori.
Maori cultivation, dispersal and active management of harakeke, as well as possible creation of wetland areas, emphasises the importance of harakeke as an economic resource prior to European colonisation, and indicates how the New Zealand landscape may have been transformed. Maori ecological knowledge can contribute new perspectives to restoration ecology and ecosystem research.

year: 2005