title: An empirical study of moment estimators for quantile approximation

authors: Mitchell, Rory

subjects: computer science

abstract: We empirically evaluate lightweight moment estimators for the single-pass quantile approximation problem, including maximum entropy methods and orthogonal series with Fourier, Cosine, Legendre, Chebyshev and Hermite basis functions. We show how to apply stable summation formulas to offset numerical precision issues for higher-order moments, leading to reliable single-pass moment estimators up to order 15. Additionally, we provide an algorithm for GPU-accelerated quantile approximation based on parallel tree reduction. Experiments evaluate the accuracy and runtime of moment estimators against the state-of-the-art KLL quantile estimator on 14,072 real-world datasets drawn from the OpenML database. Our analysis highlights the effectiveness of variants of moment-based quantile approximation for highly space efficient summaries: their average performance using as few as five sample moments can approach the performance of a KLL sketch containing 500 elements. Experiments also illustrate the difficulty of applying the method reliably and showcases which moment-based approximations can be expected to fail or perform poorly.

text: An empirical study of moment estimators for quantile approximation We empirically evaluate lightweight moment estimators for the single-pass quantile approximation problem, including maximum entropy methods and orthogonal series with Fourier, Cosine, Legendre, Chebyshev and Hermite basis functions. We show how to apply stable summation formulas to offset numerical precision issues for higher-order moments, leading to reliable single-pass moment estimators up to order 15. Additionally, we provide an algorithm for GPU-accelerated quantile approximation based on parallel tree reduction. Experiments evaluate the accuracy and runtime of moment estimators against the state-of-the-art KLL quantile estimator on 14,072 real-world datasets drawn from the OpenML database. Our analysis highlights the effectiveness of variants of moment-based quantile approximation for highly space efficient summaries: their average performance using as few as five sample moments can approach the performance of a KLL sketch containing 500 elements. Experiments also illustrate the difficulty of applying the method reliably and showcases which moment-based approximations can be expected to fail or perform poorly.

year: 2021

title: A visual discrimination task to identify judgement bias in hens (Gallus gallus domesticus).

authors: Buchanan, Nicky

subjects: judgement bias

abstract: This study aimed to investigate whether the use of a judgement bias task with differential reinforcement was suitable to assess emotional states (positive or negative affect) in domestic hens.  Six hens were trained to discriminate between a vertical and horizontal rectangle using an operant procedure with differential reinforcement to each stimulus in order to induce a positive or negative affect.  Three ambiguous rectangles were introduced at intermediate angles and responses to these and the two learned rectangles were used to measure for judgement bias.  Initial judgement bias probes measured response bias using three different foods as reinforcement; poultry pellets, wheat and puffed wheat in a one food magazine operant chamber.  The chamber was then modified from a single food magazine to a double food magazine allowing six different food combinations with the three foods and differing reinforcement periods.  Judgement bias probes measured response bias to the learned and ambiguous rectangles using combinations of each food type.  Overall response latencies revealed a consistent pattern across all six hens with the fastest response times to the vertical (positive) stimulus and slowest response times to the horizontal (negative) stimulus.  Results indicate that judgement bias was best measured and identified in the one food magazine chamber with four of the six hens consistently demonstrating positive affect and two hens demonstrating slight negative affect.  It was found that results varied in the double magazine chamber revealing both response bias and food preference.

text: A visual discrimination task to identify judgement bias in hens (Gallus gallus domesticus). This study aimed to investigate whether the use of a judgement bias task with differential reinforcement was suitable to assess emotional states (positive or negative affect) in domestic hens.  Six hens were trained to discriminate between a vertical and horizontal rectangle using an operant procedure with differential reinforcement to each stimulus in order to induce a positive or negative affect.  Three ambiguous rectangles were introduced at intermediate angles and responses to these and the two learned rectangles were used to measure for judgement bias.  Initial judgement bias probes measured response bias using three different foods as reinforcement; poultry pellets, wheat and puffed wheat in a one food magazine operant chamber.  The chamber was then modified from a single food magazine to a double food magazine allowing six different food combinations with the three foods and differing reinforcement periods.  Judgement bias probes measured response bias to the learned and ambiguous rectangles using combinations of each food type.  Overall response latencies revealed a consistent pattern across all six hens with the fastest response times to the vertical (positive) stimulus and slowest response times to the horizontal (negative) stimulus.  Results indicate that judgement bias was best measured and identified in the one food magazine chamber with four of the six hens consistently demonstrating positive affect and two hens demonstrating slight negative affect.  It was found that results varied in the double magazine chamber revealing both response bias and food preference.

year: 2016

title: Lessons learned from the MV Rena: Reimagining maritime and resource management law

authors: Paul, Adrienne Joy

subjects: Resource Management Law - New Zealand

abstract: The main research question in this thesis is what lessons can Aotearoa New Zealand learn from the MV Rena grounding accident? This research is an historical account of the legal framework existing at the time of the MV Rena grounding. In addition, the thesis will outline the surrounding marine environment to examine the relevant regulatory system.
In the early morning of 5th October 2011, the MV Rena vessel struck Ōtāiti (Astrolabe Reef).  Initially, the accident concerned a response to the safety of the crew on board the MV Rena. However, the seriousness of the damage to the hull with part of Ōtāiti reef protruding through the keel, presented issues concerning the recovery strategy for the vessel and cargo from the coastal marine area.  The MV Rena grounding released oil, cargo, and equipment into the surrounding marine environment of Ōtāiti. The oil, cargo and equipment travelled by the ocean currents, spreading across large areas of the ocean. This caused environmental effects across the coastal marine area in the Bay of Plenty region. The grounding was the “worst maritime environmental disaster” Aotearoa New Zealand had ever seen. 

The government of the day and the MV Rena owner are committed to international obligations for preparing and responding to maritime disasters and marine pollution. However, the government of Aotearoa New Zealand was not a party to international obligations addressing groundings relative to bunker oil. In addition, when responding to environmental effects from the grounding the legal processes regulating the maritime and resource management system, caused distress to the local community in the Bay of Plenty region. Specifically, the people of Motiti Island (“Motiti”), relative to preserving and protecting their cultural and spiritual relationship with Ōtāiti and Motiti.

An analysis of maritime and resource management law at the international level and domestic level is explored in this thesis. Such as, marine pollution, and indigenous peoples’ rights (iwi Māori) in connection with the Maritime Transport Act 1994, the Resource Management Act 1991, the Waitangi Tribunal process and related planning and policy instruments.  The research concludes that, had the government of the day ratified relevant conventions prior to the MV Rena grounding incident, the outcome of the location of the ship may have been a completely different result, such as a full wreck removal, without opposition. Additionally, the research concludes that the gap in the laws regulating marine environments did not equip iwi Māori with protecting their interests, resulting in a spiritual injustice to the people of Motiti. This research reveals that maritime and resource management law still has a long way to go with supporting the indigenous people’s voice in Aotearoa New Zealand for sustainable marine solutions. This thesis conclude with recommendations directed at better maritime and resource management regulations and indigenous peoples’ involvement.

text: Lessons learned from the MV Rena: Reimagining maritime and resource management law The main research question in this thesis is what lessons can Aotearoa New Zealand learn from the MV Rena grounding accident? This research is an historical account of the legal framework existing at the time of the MV Rena grounding. In addition, the thesis will outline the surrounding marine environment to examine the relevant regulatory system.
In the early morning of 5th October 2011, the MV Rena vessel struck Ōtāiti (Astrolabe Reef).  Initially, the accident concerned a response to the safety of the crew on board the MV Rena. However, the seriousness of the damage to the hull with part of Ōtāiti reef protruding through the keel, presented issues concerning the recovery strategy for the vessel and cargo from the coastal marine area.  The MV Rena grounding released oil, cargo, and equipment into the surrounding marine environment of Ōtāiti. The oil, cargo and equipment travelled by the ocean currents, spreading across large areas of the ocean. This caused environmental effects across the coastal marine area in the Bay of Plenty region. The grounding was the “worst maritime environmental disaster” Aotearoa New Zealand had ever seen. 

The government of the day and the MV Rena owner are committed to international obligations for preparing and responding to maritime disasters and marine pollution. However, the government of Aotearoa New Zealand was not a party to international obligations addressing groundings relative to bunker oil. In addition, when responding to environmental effects from the grounding the legal processes regulating the maritime and resource management system, caused distress to the local community in the Bay of Plenty region. Specifically, the people of Motiti Island (“Motiti”), relative to preserving and protecting their cultural and spiritual relationship with Ōtāiti and Motiti.

An analysis of maritime and resource management law at the international level and domestic level is explored in this thesis. Such as, marine pollution, and indigenous peoples’ rights (iwi Māori) in connection with the Maritime Transport Act 1994, the Resource Management Act 1991, the Waitangi Tribunal process and related planning and policy instruments.  The research concludes that, had the government of the day ratified relevant conventions prior to the MV Rena grounding incident, the outcome of the location of the ship may have been a completely different result, such as a full wreck removal, without opposition. Additionally, the research concludes that the gap in the laws regulating marine environments did not equip iwi Māori with protecting their interests, resulting in a spiritual injustice to the people of Motiti. This research reveals that maritime and resource management law still has a long way to go with supporting the indigenous people’s voice in Aotearoa New Zealand for sustainable marine solutions. This thesis conclude with recommendations directed at better maritime and resource management regulations and indigenous peoples’ involvement.

year: 2022