title: A Comparison of Multi-instance Learning Algorithms

authors: Dong, Lin

subjects: machine learning

abstract: Motivated by various challenging real-world applications, such as drug activity prediction and image retrieval, multi-instance (MI) learning has attracted considerable interest in recent years.  Compared with standard supervised learning, the MI learning task is more difficult as the label information of each training example is incomplete. Many MI algorithms have been proposed. Some of them are specifically designed for MI problems whereas others have been upgraded or adapted from standard single-instance learning algorithms.  Most algorithms have been evaluated on only one or two benchmark datasets, and there is a lack of systematic comparisons of MI learning algorithms.

This thesis presents a comprehensive study of MI learning algorithms that aims to compare their performance and find a suitable way to properly address different MI problems. First, it briefly reviews the history of research on MI learning. Then it discusses five general classes of MI approaches that cover a total of 16 MI algorithms. After that, it presents empirical results for these algorithms that were obtained from 15 datasets which involve five different real-world application domains.  Finally, some conclusions are drawn from these results: (1) applying suitable standard single-instance learners to MI problems can often generate the best result on the datasets that were tested, (2) algorithms exploiting the standard asymmetric MI assumption do not show significant advantages over approaches using the so-called collective assumption, and (3) different MI approaches are suitable for different application domains, and no MI algorithm works best on all MI problems.

text: A Comparison of Multi-instance Learning Algorithms Motivated by various challenging real-world applications, such as drug activity prediction and image retrieval, multi-instance (MI) learning has attracted considerable interest in recent years.  Compared with standard supervised learning, the MI learning task is more difficult as the label information of each training example is incomplete. Many MI algorithms have been proposed. Some of them are specifically designed for MI problems whereas others have been upgraded or adapted from standard single-instance learning algorithms.  Most algorithms have been evaluated on only one or two benchmark datasets, and there is a lack of systematic comparisons of MI learning algorithms.

This thesis presents a comprehensive study of MI learning algorithms that aims to compare their performance and find a suitable way to properly address different MI problems. First, it briefly reviews the history of research on MI learning. Then it discusses five general classes of MI approaches that cover a total of 16 MI algorithms. After that, it presents empirical results for these algorithms that were obtained from 15 datasets which involve five different real-world application domains.  Finally, some conclusions are drawn from these results: (1) applying suitable standard single-instance learners to MI problems can often generate the best result on the datasets that were tested, (2) algorithms exploiting the standard asymmetric MI assumption do not show significant advantages over approaches using the so-called collective assumption, and (3) different MI approaches are suitable for different application domains, and no MI algorithm works best on all MI problems.

year: 2006

title: Boat electrofishing survey of five Waitakere City ponds

authors: Hicks, Brendan J.

subjects: New Zealand

abstract: We conducted a fish survey of five ponds (Lake Panorama, Paremuka Pond 1 & 2, Danica Esplanade and Longbush Pond) in the Waitakere District by single-pass boat electrofishing on 18 and 19 of July 2007. We caught 337 fish comprising four introduced and two native fish species in 2.89 km of fished distance from all 5 ponds. Assuming that each of the two bow-mounted anodes caught fish within a 1 m radius, the width fished was 4 m, and the total area fished was 11,537 m² or 1.154 ha. The water temperature for the 5 different ponds ranged between 10.8°C and 14.9°C.
In Lake Panorama, shortfinned eel (Anguilla australis) were the most numerous species caught (130 fish ha⁻¹ ), followed by perch (Perca fluviatilis) (100 fish ha⁻¹) and tench (Tinca tinca) (40 fish ha⁻¹).
In Paremuka Pond 1, koi carp (Cyprinus carpio) were the most numerous species caught (120 fish ha⁻¹), followed by shortfinned eels (50 fish ha⁻¹).

In Paremuka Pond 2, koi carp were again the most numerous species caught (340 fish ha⁻¹), followed by tench (250 fish ha⁻¹) and shortfinned eels (70 fish ha⁻¹).

In Danica Esplanade and Longbush Pond, shortfinned eels were the most numerous species caught (140 and 550 fish ha⁻¹respectively), followed by mosquitofish (Gambusia affinis). There was more macrophyte cover around the edges of Danica Esplanade compared to Longbush Pond and this decreased the catch rate as a large number of eels in Danica Esplanade were sighted but were unable to be captured. 

Koi carp were only caught in the Paremuka ponds. The majority of koi carp were caught on the edges of the lake in macrophytes and rushes. Koi carp biomasses were highest in Paremuka Pond 2 at 261 kg ha⁻¹ compared to 106 kg ha⁻¹ in Paremuka Pond 1. Biomass is a more accurate reflection of the potential ecological impact of koi carp than their density. Previous results suggest that 21-73% of the total population is caught on the first removal, depending on water visibility. As we fished the area at each site only once, the estimates in this survey represent a minimum abundance, and true population sizes are likely to be 1.4-4.8 times greater. The density of eels in both the Paremuka ponds is also likely to be higher as a large proportion of eels were able to escape into the macrophytes before they could be captured in the nets. Mosquitofish were also observed to be living in both the Paremuka ponds. Of ecological concern for the Paremuka ponds is the dominance of the fish biomass by introduced koi carp, which have a deleterious impact on aquatic habitats. Another concern for these ponds is the presence of small koi carp (<200 mm), which suggests that natural spawning is most likely occurring, although recent releases of carp into the ponds in another possibility.

The fate of the introduced fish varied depending on what species they were. Perch and tench were released back into the ponds after captures as they are classified as sports fish. Koi carp and mosquitofish are classified as unwanted organisms and were humanely destroyed with an anaesthetic overdose (benzocaine), and retained for further analysis.

text: Boat electrofishing survey of five Waitakere City ponds We conducted a fish survey of five ponds (Lake Panorama, Paremuka Pond 1 & 2, Danica Esplanade and Longbush Pond) in the Waitakere District by single-pass boat electrofishing on 18 and 19 of July 2007. We caught 337 fish comprising four introduced and two native fish species in 2.89 km of fished distance from all 5 ponds. Assuming that each of the two bow-mounted anodes caught fish within a 1 m radius, the width fished was 4 m, and the total area fished was 11,537 m² or 1.154 ha. The water temperature for the 5 different ponds ranged between 10.8°C and 14.9°C.
In Lake Panorama, shortfinned eel (Anguilla australis) were the most numerous species caught (130 fish ha⁻¹ ), followed by perch (Perca fluviatilis) (100 fish ha⁻¹) and tench (Tinca tinca) (40 fish ha⁻¹).
In Paremuka Pond 1, koi carp (Cyprinus carpio) were the most numerous species caught (120 fish ha⁻¹), followed by shortfinned eels (50 fish ha⁻¹).

In Paremuka Pond 2, koi carp were again the most numerous species caught (340 fish ha⁻¹), followed by tench (250 fish ha⁻¹) and shortfinned eels (70 fish ha⁻¹).

In Danica Esplanade and Longbush Pond, shortfinned eels were the most numerous species caught (140 and 550 fish ha⁻¹respectively), followed by mosquitofish (Gambusia affinis). There was more macrophyte cover around the edges of Danica Esplanade compared to Longbush Pond and this decreased the catch rate as a large number of eels in Danica Esplanade were sighted but were unable to be captured. 

Koi carp were only caught in the Paremuka ponds. The majority of koi carp were caught on the edges of the lake in macrophytes and rushes. Koi carp biomasses were highest in Paremuka Pond 2 at 261 kg ha⁻¹ compared to 106 kg ha⁻¹ in Paremuka Pond 1. Biomass is a more accurate reflection of the potential ecological impact of koi carp than their density. Previous results suggest that 21-73% of the total population is caught on the first removal, depending on water visibility. As we fished the area at each site only once, the estimates in this survey represent a minimum abundance, and true population sizes are likely to be 1.4-4.8 times greater. The density of eels in both the Paremuka ponds is also likely to be higher as a large proportion of eels were able to escape into the macrophytes before they could be captured in the nets. Mosquitofish were also observed to be living in both the Paremuka ponds. Of ecological concern for the Paremuka ponds is the dominance of the fish biomass by introduced koi carp, which have a deleterious impact on aquatic habitats. Another concern for these ponds is the presence of small koi carp (<200 mm), which suggests that natural spawning is most likely occurring, although recent releases of carp into the ponds in another possibility.

The fate of the introduced fish varied depending on what species they were. Perch and tench were released back into the ponds after captures as they are classified as sports fish. Koi carp and mosquitofish are classified as unwanted organisms and were humanely destroyed with an anaesthetic overdose (benzocaine), and retained for further analysis.

year: 2007

title: The anthropologist as tribal advocate

authors: Hopa, Ngapare K

subjects: economic conditions

abstract: My colleague has outlined some of the major issues facing New Zealand and its indigenous Polynesians - the Maaori - who not so long ago were ranked among the most documented in the world and the country as THE laboratory of race relations.
The present disadvantaged and dependent status of Maaori people show how illusory that notion is and, for New Zealand anthropologists, the challenge it presents in helping Maaori to attain socio-economic sovereignty within the 'partnership' promised by the Treaty of Waitangi.
In the late 60s and since, a few 'radical' mostly 'native' anthropologists can be said to have risen to the challenge that Gough (1968) and others, laid down, but it cannot be said, even now, that the profession as a whole in New Zealand, has been responsive.
Perhaps it is still committed to the myth of scientific objectivity, or, after regarding themselves as champions of a powerless and marginal people, has not recovered from the accusation of impotency during the social ferment of the 70s and since. To be fair, there were a few individuals who were allied with the protest movement but whose contributions were not acknowledged. They rode out the storm however and have continued to contribute significantly to the Maaori cause.

text: The anthropologist as tribal advocate My colleague has outlined some of the major issues facing New Zealand and its indigenous Polynesians - the Maaori - who not so long ago were ranked among the most documented in the world and the country as THE laboratory of race relations.
The present disadvantaged and dependent status of Maaori people show how illusory that notion is and, for New Zealand anthropologists, the challenge it presents in helping Maaori to attain socio-economic sovereignty within the 'partnership' promised by the Treaty of Waitangi.
In the late 60s and since, a few 'radical' mostly 'native' anthropologists can be said to have risen to the challenge that Gough (1968) and others, laid down, but it cannot be said, even now, that the profession as a whole in New Zealand, has been responsive.
Perhaps it is still committed to the myth of scientific objectivity, or, after regarding themselves as champions of a powerless and marginal people, has not recovered from the accusation of impotency during the social ferment of the 70s and since. To be fair, there were a few individuals who were allied with the protest movement but whose contributions were not acknowledged. They rode out the storm however and have continued to contribute significantly to the Maaori cause.

year: 1988