title: Selected data exploration methods in hydroclimatology

authors: Vetrova, Varvara

subjects: hydrclimatology

abstract: The volumes of climatological data are rapidly growing due to development of new acquisition platforms and advances in data storage technologies. Such advances provide new challenging problems for data analysis methods. As a result, there is an increasing interest in application and development of new machine learning and data mining methods in climatological data analysis.

This dissertation contributes to the field of data analysis by evaluation of selected methods and developing new techniques with application to hydro-climatological datasets. 

It is shown that data pre-processing with the decimated wavelet discrete transform can cause false predictive accuracy in regression machine learning algorithms. A general result is obtained that a decimated wavelet discrete transform based on a pyramidal algorithm requires utilizing some future values of the time series concerned. When the discrete wavelet transform is utilized as a pre-processing step for forecasting the time series, the necessary independence of calibration and validation data is compromised. This in turn translates into over-optimistic forecasting accuracy or even giving the illusion of forecasting skill when there in none. The obtained result is general and has wide implications in any discipline where the discrete wavelet transform is utilised in forecasting frameworks.

In addition, a general framework for creating simple predictive models is presented, based on LASSO regularised regression. The method is illustrated for time series modelling with external event forcing but the approach has general applicability. 

As a contribution to association discovery, two tests of bivariate association are developed. The first method is designed for detecting threshold-like associations in a scatter plot with particular reference to testing the significance of the extent of a data-sparse region within a scatter plot. The second method is a more general test of non-random associations. Both methods utilise significance testing based on randomizations.

Finally, LASSO regularized regression is investigated as a tool for discovering informative large scale climatogical predictors of local hydrological processes. A cross-validation scheme is proposed, which is related to practical forecasts of the next time interval to come, while at the same time maximising use of available information. The proposed methodology was applied to a case study predicting next-season river discharges in the Upper Waitaki River in New Zealand. The proposed forecasting methodology and cross-validation frameworks are applicable for similar hydroclimatological forecasting situations. The physical aspect of this part of the study included discovering the influence of the Interdecadal Pacific Oscillation on winter discharges in the upper Waitaki catchment.

text: Selected data exploration methods in hydroclimatology The volumes of climatological data are rapidly growing due to development of new acquisition platforms and advances in data storage technologies. Such advances provide new challenging problems for data analysis methods. As a result, there is an increasing interest in application and development of new machine learning and data mining methods in climatological data analysis.

This dissertation contributes to the field of data analysis by evaluation of selected methods and developing new techniques with application to hydro-climatological datasets. 

It is shown that data pre-processing with the decimated wavelet discrete transform can cause false predictive accuracy in regression machine learning algorithms. A general result is obtained that a decimated wavelet discrete transform based on a pyramidal algorithm requires utilizing some future values of the time series concerned. When the discrete wavelet transform is utilized as a pre-processing step for forecasting the time series, the necessary independence of calibration and validation data is compromised. This in turn translates into over-optimistic forecasting accuracy or even giving the illusion of forecasting skill when there in none. The obtained result is general and has wide implications in any discipline where the discrete wavelet transform is utilised in forecasting frameworks.

In addition, a general framework for creating simple predictive models is presented, based on LASSO regularised regression. The method is illustrated for time series modelling with external event forcing but the approach has general applicability. 

As a contribution to association discovery, two tests of bivariate association are developed. The first method is designed for detecting threshold-like associations in a scatter plot with particular reference to testing the significance of the extent of a data-sparse region within a scatter plot. The second method is a more general test of non-random associations. Both methods utilise significance testing based on randomizations.

Finally, LASSO regularized regression is investigated as a tool for discovering informative large scale climatogical predictors of local hydrological processes. A cross-validation scheme is proposed, which is related to practical forecasts of the next time interval to come, while at the same time maximising use of available information. The proposed methodology was applied to a case study predicting next-season river discharges in the Upper Waitaki River in New Zealand. The proposed forecasting methodology and cross-validation frameworks are applicable for similar hydroclimatological forecasting situations. The physical aspect of this part of the study included discovering the influence of the Interdecadal Pacific Oscillation on winter discharges in the upper Waitaki catchment.

year: 2016

title: Physical inactivity in prevails in later life

authors: Grant, Bevan C.

abstract: The majority of people over 70 years may self-report themselves to be in good health but just being older means they are more likely to experience a range of health related ups and downs than in their younger years. One explanation for this is that the older population carries a progressively heavier burden of chronic disease and disability than their younger cohorts. With a changing demographic and in particular an ageing population, it is not surprising that politicians and health professionals are keen to intervene – mostly because of a presumed high cost of not-so-good health.

text: Physical inactivity in prevails in later life The majority of people over 70 years may self-report themselves to be in good health but just being older means they are more likely to experience a range of health related ups and downs than in their younger years. One explanation for this is that the older population carries a progressively heavier burden of chronic disease and disability than their younger cohorts. With a changing demographic and in particular an ageing population, it is not surprising that politicians and health professionals are keen to intervene – mostly because of a presumed high cost of not-so-good health.

year: 2011

title: The Daldy Mcwilliams ‘Outrage’ of 1879

authors: Hart, Philip

abstract: In the later 1870s, conflicts developed near Paeroa between a small hapu, Ngati Hako, and other hapu over land sales and surveys. In 1879, after some members of Ngati Koi offered to sell the Pukehanga Block, at Rotokohu, between Paeroa and Te Aroha, to the Crown, surveyors were sent to determine the boundaries despite threats of violence from Ngati Hako. These threats became a reality with shots being fired, wounding a surveyor’s assistant, ‘Daldy’ McWilliams, who survived by playing dead. Despite Pakeha fury about a ‘weak’ response, officials reacted cautiously, fearing to provoke a wider conflict. 
Instead of trying to arrest the two men accused of the attempted murder, which would have been difficult, because Ngati Hako claimed their action was justified the Native Minister encouraged senior Hauraki rangatira to convene a rununga to examine their claim. Ngati Hako said that the block of land was theirs, and as previously other land had been surveyed without their permission they had taken this action. The government was criticized for paying advances on a block that had not been through the land court, and the rununga determined that although Ngati Hako had acted wrongfully, their action could be justified. When Ngati Hako refused to hand over the two accused to the authorities, the rununga claimed not to have the power to hand them over; Ngati Hako then constructed two pa to defend themselves.
Such actions provoked much frustration and criticisms of the government amongst Pakeha, but officials who investigated Ngati Hako’s complaints agreed that they had indeed lost land unjustly. Once the owners of a large domain, they had lost their land to the invading Marutuahu, whose slaves they became. When the two accused were arrested in 1882 one was found not guilty and the other was amnestied after eight months in prison because it was believed that, as rangatira, they probably had not fired the shots but had taken the responsibility for the actions of their hapu. As for McWilliams, he received what he considered inadequate compensation.
This ‘outrage’ was the first and only time in Hauraki that a Maori had shot a Pakeha, and the government’s cautious but firm response meant that the ‘peace of Hauraki’, although disturbed for a while, was maintained.

text: The Daldy Mcwilliams ‘Outrage’ of 1879 In the later 1870s, conflicts developed near Paeroa between a small hapu, Ngati Hako, and other hapu over land sales and surveys. In 1879, after some members of Ngati Koi offered to sell the Pukehanga Block, at Rotokohu, between Paeroa and Te Aroha, to the Crown, surveyors were sent to determine the boundaries despite threats of violence from Ngati Hako. These threats became a reality with shots being fired, wounding a surveyor’s assistant, ‘Daldy’ McWilliams, who survived by playing dead. Despite Pakeha fury about a ‘weak’ response, officials reacted cautiously, fearing to provoke a wider conflict. 
Instead of trying to arrest the two men accused of the attempted murder, which would have been difficult, because Ngati Hako claimed their action was justified the Native Minister encouraged senior Hauraki rangatira to convene a rununga to examine their claim. Ngati Hako said that the block of land was theirs, and as previously other land had been surveyed without their permission they had taken this action. The government was criticized for paying advances on a block that had not been through the land court, and the rununga determined that although Ngati Hako had acted wrongfully, their action could be justified. When Ngati Hako refused to hand over the two accused to the authorities, the rununga claimed not to have the power to hand them over; Ngati Hako then constructed two pa to defend themselves.
Such actions provoked much frustration and criticisms of the government amongst Pakeha, but officials who investigated Ngati Hako’s complaints agreed that they had indeed lost land unjustly. Once the owners of a large domain, they had lost their land to the invading Marutuahu, whose slaves they became. When the two accused were arrested in 1882 one was found not guilty and the other was amnestied after eight months in prison because it was believed that, as rangatira, they probably had not fired the shots but had taken the responsibility for the actions of their hapu. As for McWilliams, he received what he considered inadequate compensation.
This ‘outrage’ was the first and only time in Hauraki that a Maori had shot a Pakeha, and the government’s cautious but firm response meant that the ‘peace of Hauraki’, although disturbed for a while, was maintained.

year: 2016