title: Performance measures for evolving predictions under delayed labelling classification

authors: Grzenda, Maciej

subjects: computer science

abstract: For many streaming classification tasks, the ground truth labels become available with a non-negligible latency. Given this delayed labelling setting, after the instance data arrives and before its true label is known, the online classifier model may change. Hence, the initial prediction can be replaced with additional periodic predictions gradually produced before the true label becomes available. The quality of these predictions may largely vary. Thus, the question arises of how to summarise the performance of these models when multiple predictions for a single instance are made due to delayed labels.In this study, we aim to provide intuitive performance measures summarising the performance of multiple predictions made for individual instances before their true labels arrive. Particular attention is paid to the fact that under the delayed label setting, the emphasis placed on the quality of initial predictions can vary depending on problem needs. The intermediate performance measures we propose complement existing initial and test-then-train performance evaluation when verification latency is observed. Results provided for both real and synthetic datasets show that the new measures can be used to easily rank methods in terms of their ability to produce and refine predictions before the true labels arrive.

text: Performance measures for evolving predictions under delayed labelling classification For many streaming classification tasks, the ground truth labels become available with a non-negligible latency. Given this delayed labelling setting, after the instance data arrives and before its true label is known, the online classifier model may change. Hence, the initial prediction can be replaced with additional periodic predictions gradually produced before the true label becomes available. The quality of these predictions may largely vary. Thus, the question arises of how to summarise the performance of these models when multiple predictions for a single instance are made due to delayed labels.In this study, we aim to provide intuitive performance measures summarising the performance of multiple predictions made for individual instances before their true labels arrive. Particular attention is paid to the fact that under the delayed label setting, the emphasis placed on the quality of initial predictions can vary depending on problem needs. The intermediate performance measures we propose complement existing initial and test-then-train performance evaluation when verification latency is observed. Results provided for both real and synthetic datasets show that the new measures can be used to easily rank methods in terms of their ability to produce and refine predictions before the true labels arrive.

year: 2020

title: A coupled hydrodynamic-ecological model of management options for restoration of Lake Ohinewai

authors: Allan, Mathew Grant

abstract: Koi carp (Cyprinus carpio) is regarded as one of the ecologically most destructive invasive freshwater species capable of degradation of shallow aquatic ecosystems. This degradation is largely due to their benthic foraging activity which resuspends sediment and increases nitrogen (N) and phosphorus (P) concentrations, leading to algal blooms. In addition, carp have the potential to excrete large quantities of nutrients into the water column. This report describes a modelling study of a shallow Waikato lake subject to invasive fish removal to investigate how carp contribute to the overall nutrient cycling at an ecosystem scale. The study site was Lake Ohinewai, a relatively small shallow, polymictic, hypertrophic riverine lake located in the northern Waikato region. Evidence of water quality degradation has been documented since the 1980's, before the introduction of carp. Lake Ohinewai has undergone an intensive programme of invasive fish removal and a permanent adult koi carp barrier was installed on the outflow drain of Lake Ohinewai to prevent passage into the lake, but allow carp to exit.

We applied DYRESM-CAEDYM (DYCD), a 1-D water quality model that has been developed at the Centre for Water Research, University of Western Australia. Daily inflows into Lake Ohinewai were derived from INCA, a process-based model. Carp-driven sediment resuspension was estimated using results from experimental ponds stocked with varying densities of carp. Carp-suspended sediment was then used to estimate carp-translocated porewater due to benthic feeding. Koi carp excretion was estimated using an allometric scaling model. Nine catchment and riparian management scenarios were tested with no fish (NF) and with current invasive koi carp removal (F). These scenarios included: simulation of current biomass; pre-removal fish biomass; reduction of external load by 50%; an all native forest catchment; climate change; DOC administered land sub-catchment retirement; enhanced lake riparian margins; stream riparian zones; and creation of a wetland. For all scenarios, specified changes in nutrient concentrations were applied to internal loads (phosphate and ammonium release rates) from the sediment.
Simulations demonstrated that, at a density of 374 kg ha⁻¹ and assuming they are feeding on the benthos, koi carp can contribute 21% of total phosphorous load and 10% of total nitrogen load via nutrient translocation. The major proportion of this load was due to koi carp excretion. While koi carp introduction in Lake Ohinewai has contributed to its current hypertrophic state based on this modelling exercise, evidence of water quality degradation was originally documented prior to koi carp introduction, and has most likely been occurring since the catchment land use was originally modified from its natural state. The simulations suggest that the removal of koi carp decreased Trophic Level Index (TLI4) from 6.45 to 6.28, indicating that koi carp removal alone is not sufficient for a significant restoration of lake water quality. In order to return the system to a stable clear water state, water clarity must improve to a level to permit significant macrophyte re-establishment. However, restoration simulations showed that at a lower TLI4 the removal of koi carp is critical to lake restoration. Simulations estimated that the removal of koi carp decreased TSS concentrations by approximately two-thirds in most of the scenarios. However, in the all-native catchment scenario, removal of koi carp was predicted to increase Secchi depth by c. 2.5 m, and reduce TSS by c. 13 mg l⁻¹.

The scenario simulations within the present study showed that integrated catchment management involving use of stream riparian zones and constructed wetlands would be required in order to restore lake water quality significantly. Using these mitigation techniques a TLI4 target of 5.27 would likely be achieved. This mesotrophic TLI4 may enable the reestablishment of macrophytes.

text: A coupled hydrodynamic-ecological model of management options for restoration of Lake Ohinewai Koi carp (Cyprinus carpio) is regarded as one of the ecologically most destructive invasive freshwater species capable of degradation of shallow aquatic ecosystems. This degradation is largely due to their benthic foraging activity which resuspends sediment and increases nitrogen (N) and phosphorus (P) concentrations, leading to algal blooms. In addition, carp have the potential to excrete large quantities of nutrients into the water column. This report describes a modelling study of a shallow Waikato lake subject to invasive fish removal to investigate how carp contribute to the overall nutrient cycling at an ecosystem scale. The study site was Lake Ohinewai, a relatively small shallow, polymictic, hypertrophic riverine lake located in the northern Waikato region. Evidence of water quality degradation has been documented since the 1980's, before the introduction of carp. Lake Ohinewai has undergone an intensive programme of invasive fish removal and a permanent adult koi carp barrier was installed on the outflow drain of Lake Ohinewai to prevent passage into the lake, but allow carp to exit.

We applied DYRESM-CAEDYM (DYCD), a 1-D water quality model that has been developed at the Centre for Water Research, University of Western Australia. Daily inflows into Lake Ohinewai were derived from INCA, a process-based model. Carp-driven sediment resuspension was estimated using results from experimental ponds stocked with varying densities of carp. Carp-suspended sediment was then used to estimate carp-translocated porewater due to benthic feeding. Koi carp excretion was estimated using an allometric scaling model. Nine catchment and riparian management scenarios were tested with no fish (NF) and with current invasive koi carp removal (F). These scenarios included: simulation of current biomass; pre-removal fish biomass; reduction of external load by 50%; an all native forest catchment; climate change; DOC administered land sub-catchment retirement; enhanced lake riparian margins; stream riparian zones; and creation of a wetland. For all scenarios, specified changes in nutrient concentrations were applied to internal loads (phosphate and ammonium release rates) from the sediment.
Simulations demonstrated that, at a density of 374 kg ha⁻¹ and assuming they are feeding on the benthos, koi carp can contribute 21% of total phosphorous load and 10% of total nitrogen load via nutrient translocation. The major proportion of this load was due to koi carp excretion. While koi carp introduction in Lake Ohinewai has contributed to its current hypertrophic state based on this modelling exercise, evidence of water quality degradation was originally documented prior to koi carp introduction, and has most likely been occurring since the catchment land use was originally modified from its natural state. The simulations suggest that the removal of koi carp decreased Trophic Level Index (TLI4) from 6.45 to 6.28, indicating that koi carp removal alone is not sufficient for a significant restoration of lake water quality. In order to return the system to a stable clear water state, water clarity must improve to a level to permit significant macrophyte re-establishment. However, restoration simulations showed that at a lower TLI4 the removal of koi carp is critical to lake restoration. Simulations estimated that the removal of koi carp decreased TSS concentrations by approximately two-thirds in most of the scenarios. However, in the all-native catchment scenario, removal of koi carp was predicted to increase Secchi depth by c. 2.5 m, and reduce TSS by c. 13 mg l⁻¹.

The scenario simulations within the present study showed that integrated catchment management involving use of stream riparian zones and constructed wetlands would be required in order to restore lake water quality significantly. Using these mitigation techniques a TLI4 target of 5.27 would likely be achieved. This mesotrophic TLI4 may enable the reestablishment of macrophytes.

year: 2016

title: Kūkupa, koro, and kai: The use of Māori vocabulary items in New Zealand English children's picture books

authors: Daly, Nicola

subjects: New Zealand

abstract: When a linguistic form from one language is used in another language, such words are known as borrowings or loan words (Crystal 2003: 56). The English language is renowned for its large capacity for borrowing and it has been suggested that the growth in internationalism in recent times has led to people seeking new words to indicate their local identity (Crystal 1995; Crystal 2003). Certainly this is the case of New Zealand English, the most distinctive aspect of which is borrowings from te reo Maori (Deverson 1991). In 1984 Deverson estimated that most New Zealanders have a passive knowledge of at least 40-50 borrowed Maori loan words (Deverson 1984). This figure has been recently revised by Macalister to 70-80 such words (20,-,63.). A study of the frequency of Maori loan words in New Zealand English in New Zealand School Journals of the 1960s and 1990s showed an incidence of around 6 words per 1,000 (Macalister 1999). Kennedy and Yamazaki (1999) also found borrowed Maori words at a rate of 6 per thousand words. Macalister (2006b) has examined the use of Maori loan words in New Zealand English across a 150 year period from 1850-2000. He examined a corpus of a little under five and a half million words from three sources: Newspapers, parliamentary debates and School Journals. Across the three sources there was an increase from 3.29 words per 1,000 in 1850 to 8.8 per thousand in 2000. Macalister lists the reasons for this change as including urbanisation of the Maori population between 1945 and 1975, which created more contact; the changing status of the Maori language with the kOhanga reo movement; the establishment of the Maori Language Commission (Te Taura Whiri i te Reo Maori) and legislation of Maori as an official language of New Zealand in 1987.

text: Kūkupa, koro, and kai: The use of Māori vocabulary items in New Zealand English children's picture books When a linguistic form from one language is used in another language, such words are known as borrowings or loan words (Crystal 2003: 56). The English language is renowned for its large capacity for borrowing and it has been suggested that the growth in internationalism in recent times has led to people seeking new words to indicate their local identity (Crystal 1995; Crystal 2003). Certainly this is the case of New Zealand English, the most distinctive aspect of which is borrowings from te reo Maori (Deverson 1991). In 1984 Deverson estimated that most New Zealanders have a passive knowledge of at least 40-50 borrowed Maori loan words (Deverson 1984). This figure has been recently revised by Macalister to 70-80 such words (20,-,63.). A study of the frequency of Maori loan words in New Zealand English in New Zealand School Journals of the 1960s and 1990s showed an incidence of around 6 words per 1,000 (Macalister 1999). Kennedy and Yamazaki (1999) also found borrowed Maori words at a rate of 6 per thousand words. Macalister (2006b) has examined the use of Maori loan words in New Zealand English across a 150 year period from 1850-2000. He examined a corpus of a little under five and a half million words from three sources: Newspapers, parliamentary debates and School Journals. Across the three sources there was an increase from 3.29 words per 1,000 in 1850 to 8.8 per thousand in 2000. Macalister lists the reasons for this change as including urbanisation of the Maori population between 1945 and 1975, which created more contact; the changing status of the Maori language with the kOhanga reo movement; the establishment of the Maori Language Commission (Te Taura Whiri i te Reo Maori) and legislation of Maori as an official language of New Zealand in 1987.

year: 2007