title: Racing committees for large datasets

authors: Frank, Eibe

subjects: Science & Technology

abstract: This paper proposes a method for generating classifiers from large datasets by building a committee of simple base classifiers using a standard boosting algorithm. It permits the processing of large datasets even if the underlying base learning algorithm cannot efficiently do so. The basic idea is to split incoming data into chunks and build a committee based on classifiers built from these individual chunks. Our method extends earlier work by introducing a method for adaptively pruning the committee. This is essential when applying the algorithm in practice because it dramatically reduces the algorithm’s running time and memory consumption. It also makes it possible to efficiently “race” committees corresponding to different chunk sizes. This is important because our empirical results show that the accuracy of the resulting committee can vary significantly with the chunk size. They also show that pruning is indeed crucial to make the method practical for large datasets in terms of running time and memory requirements. Surprisingly, the results demonstrate that pruning can also improve accuracy.

text: Racing committees for large datasets This paper proposes a method for generating classifiers from large datasets by building a committee of simple base classifiers using a standard boosting algorithm. It permits the processing of large datasets even if the underlying base learning algorithm cannot efficiently do so. The basic idea is to split incoming data into chunks and build a committee based on classifiers built from these individual chunks. Our method extends earlier work by introducing a method for adaptively pruning the committee. This is essential when applying the algorithm in practice because it dramatically reduces the algorithm’s running time and memory consumption. It also makes it possible to efficiently “race” committees corresponding to different chunk sizes. This is important because our empirical results show that the accuracy of the resulting committee can vary significantly with the chunk size. They also show that pruning is indeed crucial to make the method practical for large datasets in terms of running time and memory requirements. Surprisingly, the results demonstrate that pruning can also improve accuracy.

year: 2002-01-01

title: The classification of substance and behavioural addictions: A preliminary investigation

authors: McLaughlan, Andre David

subjects: pathological gambling

abstract: The term addiction has been used to refer to impaired control over substance use for several centuries however recently there has been a shift toward using this term in the context of non-substance use disorders, such as pathological gambling. A preliminary investigation was conducted in an attempt to clarify the most appropriate classification of 'behavioural addictions'. Participants with alcohol dependence (AD, n = 24), pathological gambling (PG, n = 20) and compulsive buying disorder (CBD, n = 14) completed an Addictive Disorder Questionnaire (ADQ); the Symptom Checklist 90 Revised (SCL-90R); Barratt Impulsivity Scale II; and substance specific adaptations of the Yale-Brown Obsessive Compulsive Scale (Y-BOCS). Although the AD group reported more severe addiction symptoms and had higher levels of depression and anxiety, there were broad similarities across the three disorders in relation to cravings, dyscontrol, impulsivity and obsessions. Despite the small sample size and the different recruitment strategies used across the groups, the findings from this preliminary study provide support for broadening addiction diagnostic definitions to include non-substance related disorders which in turn may contribute to the development of more efficacious treatments.

text: The classification of substance and behavioural addictions: A preliminary investigation The term addiction has been used to refer to impaired control over substance use for several centuries however recently there has been a shift toward using this term in the context of non-substance use disorders, such as pathological gambling. A preliminary investigation was conducted in an attempt to clarify the most appropriate classification of 'behavioural addictions'. Participants with alcohol dependence (AD, n = 24), pathological gambling (PG, n = 20) and compulsive buying disorder (CBD, n = 14) completed an Addictive Disorder Questionnaire (ADQ); the Symptom Checklist 90 Revised (SCL-90R); Barratt Impulsivity Scale II; and substance specific adaptations of the Yale-Brown Obsessive Compulsive Scale (Y-BOCS). Although the AD group reported more severe addiction symptoms and had higher levels of depression and anxiety, there were broad similarities across the three disorders in relation to cravings, dyscontrol, impulsivity and obsessions. Despite the small sample size and the different recruitment strategies used across the groups, the findings from this preliminary study provide support for broadening addiction diagnostic definitions to include non-substance related disorders which in turn may contribute to the development of more efficacious treatments.

year: 2012

title: Māori and medications: What happens when the pills go home?

authors: Nikora, Linda Waimarie

subjects: Māori

abstract: Chronic illnesses are a feature of many Māori homescapes. These illnesses are often managed at home through the use of health technologies, particularly medications. This article explores the meanings given to medications and the use of this health technology in four Māori households. We use a range of qualitative methods to engage with householders and to document how medications are acculturated into Māori homescapes and everyday lives. From our discussions with householders about the procurement, storage, emplacement and administration of medications emerged five culturally patterned orientations to treating with medications. They are: 1) storage and administration practices that corresponded with the Māori hygiene practices of tapu (prohibited) and noa (permitted); 2) reminder strategies, or ngā pūrere whakamāharahara; 3) the enactment of the value of manaakitanga (kindness) in care relationships; 4) pōharatanga, or attitudes towards medication procurement and administration in households textured by low socio-economic status; and 5) rangatiratanga, the right of people to manage and make decisions about their own lives and health status. This study presents a view of how medications are acculturated into Māori homescapes, relationships and daily routines. The use of health technologies by health professionals to interrupt illness and improve quality of life must be cognisant of the cultural contexts into which medications are prescribed.

text: Māori and medications: What happens when the pills go home? Chronic illnesses are a feature of many Māori homescapes. These illnesses are often managed at home through the use of health technologies, particularly medications. This article explores the meanings given to medications and the use of this health technology in four Māori households. We use a range of qualitative methods to engage with householders and to document how medications are acculturated into Māori homescapes and everyday lives. From our discussions with householders about the procurement, storage, emplacement and administration of medications emerged five culturally patterned orientations to treating with medications. They are: 1) storage and administration practices that corresponded with the Māori hygiene practices of tapu (prohibited) and noa (permitted); 2) reminder strategies, or ngā pūrere whakamāharahara; 3) the enactment of the value of manaakitanga (kindness) in care relationships; 4) pōharatanga, or attitudes towards medication procurement and administration in households textured by low socio-economic status; and 5) rangatiratanga, the right of people to manage and make decisions about their own lives and health status. This study presents a view of how medications are acculturated into Māori homescapes, relationships and daily routines. The use of health technologies by health professionals to interrupt illness and improve quality of life must be cognisant of the cultural contexts into which medications are prescribed.

year: 2011