title: Online evaluation of email streaming classifiers using GNUsmail

authors: Carmona-Cejudo, José M.

subjects: Email Classiﬁcation

abstract: Real-time email classiﬁcation is a challenging task because of its online nature, subject to concept-drift. Identifying spam, where only two labels exist, has received great attention in the literature. We are nevertheless interested in classiﬁcation involving multiple folders, which is an additional source of complexity. Moreover, neither cross-validation nor other sampling procedures are suitable for data streams evaluation. Therefore, other metrics, like the prequential error, have been proposed. However, the prequential error poses some problems, which can be alleviated by using mechanisms such as fading factors.
In this paper we present GNUsmail, an open-source extensible framework for email classiﬁcation, and focus on its ability to perform online evaluation. GNUsmail’s architecture supports incremental and online learning, and it can be used to compare different online mining methods, using state-of-art evaluation metrics.
We show how GNUsmail can be used to compare different algorithms, including a tool for launching replicable experiments.

text: Online evaluation of email streaming classifiers using GNUsmail Real-time email classiﬁcation is a challenging task because of its online nature, subject to concept-drift. Identifying spam, where only two labels exist, has received great attention in the literature. We are nevertheless interested in classiﬁcation involving multiple folders, which is an additional source of complexity. Moreover, neither cross-validation nor other sampling procedures are suitable for data streams evaluation. Therefore, other metrics, like the prequential error, have been proposed. However, the prequential error poses some problems, which can be alleviated by using mechanisms such as fading factors.
In this paper we present GNUsmail, an open-source extensible framework for email classiﬁcation, and focus on its ability to perform online evaluation. GNUsmail’s architecture supports incremental and online learning, and it can be used to compare different online mining methods, using state-of-art evaluation metrics.
We show how GNUsmail can be used to compare different algorithms, including a tool for launching replicable experiments.

year: 2011

title: River Mouth Processes and Morphodynamics on a Mixed Sand-Gravel Beach

authors: Paterson, Adam Karl

subjects: Ashburton river

abstract: Where the Ashburton river meets the sea it is impounded by a mixed sand-gravel barrier, formed through littoral transport of sediment, causing a lagoon to form, locally referred to as hapua. From the hapua, discharge to the sea is maintained through small, ephemeral channels, which are unstable and are subject to morphological change in response to fluctuations in longshore transport of gravel and variations in river flow rate. There are few descriptions of the morphodynamics of these highly changeable features, particularly changes that occur over short time scales of hours to weeks.
To investigate the patterns and processes involved in the migration of drainage channels, several new instruments were trialed. A methodology of was developed to provide estimates of longshore transport on a gravel beach using a Gravel Transport Sensor. Video camera technology was the primary tool used to study river mouth morphodynamics. The camera provided hourly images of the environment, enabling qualitative assessment using movies of the images to observe morphologic changes, and quantitative measurement of the migration of the channel. Measurements of river flow, wave climate and lagoon water levels were also gathered to investigate the relationships between the morphological response and the forcing factors.
Results of the study showed that the ends of the channel behave differently, with the lagoon end remaining more stable than the seaward end. The seaward end is more exposed to the high wave energy prevalent along this coast. The wave climate, especially wave period and direction, were found to be predictors for the migration rate. The location of the seaward end is more variable due to the fluctuations in wave climate, differing from the lagoon end which is influenced predominantly by river flow rates. It has been found that the migration of the lagoon end occurs in 'steps', which are separated by raised gravel banks, the single persistent feature throughout the study. This stepping migration is driven primarily through episodic events such as high river flow or large wave events.

text: River Mouth Processes and Morphodynamics on a Mixed Sand-Gravel Beach Where the Ashburton river meets the sea it is impounded by a mixed sand-gravel barrier, formed through littoral transport of sediment, causing a lagoon to form, locally referred to as hapua. From the hapua, discharge to the sea is maintained through small, ephemeral channels, which are unstable and are subject to morphological change in response to fluctuations in longshore transport of gravel and variations in river flow rate. There are few descriptions of the morphodynamics of these highly changeable features, particularly changes that occur over short time scales of hours to weeks.
To investigate the patterns and processes involved in the migration of drainage channels, several new instruments were trialed. A methodology of was developed to provide estimates of longshore transport on a gravel beach using a Gravel Transport Sensor. Video camera technology was the primary tool used to study river mouth morphodynamics. The camera provided hourly images of the environment, enabling qualitative assessment using movies of the images to observe morphologic changes, and quantitative measurement of the migration of the channel. Measurements of river flow, wave climate and lagoon water levels were also gathered to investigate the relationships between the morphological response and the forcing factors.
Results of the study showed that the ends of the channel behave differently, with the lagoon end remaining more stable than the seaward end. The seaward end is more exposed to the high wave energy prevalent along this coast. The wave climate, especially wave period and direction, were found to be predictors for the migration rate. The location of the seaward end is more variable due to the fluctuations in wave climate, differing from the lagoon end which is influenced predominantly by river flow rates. It has been found that the migration of the lagoon end occurs in 'steps', which are separated by raised gravel banks, the single persistent feature throughout the study. This stepping migration is driven primarily through episodic events such as high river flow or large wave events.

year: 2000

title: Issues in Maori Language Planning and Revitalisation

authors: Harlow, Ray

subjects: Te reo Māori

abstract: All languages which have undergone changes of status in the course of their histories have been the subject of language planning, be this consistent or piecemeal, officially driven or diffuse. In some cases, the processes have been and are still relatively ‘painless’ or even subliminal, at least as far as much of the population speaking the language is concerned. English is an extreme case in this respect, so that Ayto (1983) is able to speak of the ‘failure of language reform’ as a striking characteristic of its history. Many of the issues which could potentially be associated with its position in both the world and in particular countries do not, to all intents and purposes, arise. They have been dealt with by history; the way English works as a lingua franca, as an official language, as an international language in a variety of domains and regions, its spelling systems, its vocabulary, just ‘growed’, with only sporadic help from conscious planning.

text: Issues in Maori Language Planning and Revitalisation All languages which have undergone changes of status in the course of their histories have been the subject of language planning, be this consistent or piecemeal, officially driven or diffuse. In some cases, the processes have been and are still relatively ‘painless’ or even subliminal, at least as far as much of the population speaking the language is concerned. English is an extreme case in this respect, so that Ayto (1983) is able to speak of the ‘failure of language reform’ as a striking characteristic of its history. Many of the issues which could potentially be associated with its position in both the world and in particular countries do not, to all intents and purposes, arise. They have been dealt with by history; the way English works as a lingua franca, as an official language, as an international language in a variety of domains and regions, its spelling systems, its vocabulary, just ‘growed’, with only sporadic help from conscious planning.

year: 2003-02