title: Quantitative Comparison of Benthic Habitat Maps Derived From Multibeam Echosounder Backscatter Data

authors: Schimel, Alexandre Carmelo Gregory

abstract: In the last decade, following the growing concern for the conservation of marine ecosystems, a wide range of approaches has been developed to achieve the identification, classification and mapping of seabed types and of benthic habitats. These approaches, commonly grouped under the denominations of Benthic Habitat Mapping or Acoustic Seabed Classification, exploit the latest scientific and engineering advancements for the exploration of the bottom of the ocean, particularly in underwater acoustics. Among all acoustic seabed-mapping systems available for this purpose, a growing interest has recently developed for Multibeam Echosounders (MBES). This interest is mainly the result of the multiplicity of these systems’ outputs (that is, bathymetry, backscatter mosaic, angular response and water-column data), which allows for multiple approaches to seabed or habitat classification and mapping. While this diversity of mapping approaches and this multiplicity of MBES data products contribute to an increasing quality of the charting of the marine environment, they also unfortunately delay the future standardization of mapping methods, which is required for their effective integration in marine environment management strategies. As a preliminary step towards such standardization, there is a need for generalized efforts of comparison of systems, data products, and mapping approaches, in order to assess the most effective ones given mapping objectives and environment conditions. The main goal of this thesis is to contribute to this effort through the development and implementation of tools and methods for the comparison of categorical seabed or habitat maps, with a specific focus on maps obtained from up-to-date methodologies of classification of MBES backscatter data. This goal is attained through the achievement of specific objectives treated sequentially. First, the need for comparison is justified through a review of the diversity characterizing the fields of Benthic Habitat Mapping and Acoustic Seabed Classification, and of their use of MBES data products. Then, a case study is presented that compare the data products from a Kongsberg EM3000 MBES to the output map of an Acoustic Ground Discrimination Software based on data from a Single-beam Echosounder and to a Sidescan Sonar mosaic, in order to illustrate how map comparison measures could contribute to the comparison of these systems. Next, a number of measures for map-to-map comparison, inspired from the literature in land remote sensing, are presented, along with methodologies for their implementation in comparison of maps described with different legends. The benefit of these measures and methodologies is demonstrated through their application to maps obtained from the acoustic datasets presented previously. Finally, a more typical implementation of these measures is presented as a case study in which the development of two up-to-date classification methodologies of MBES backscatter data is complemented by the quantitative comparison of their output maps. In the process of developing and illustrating the use of methods for the assessment of map-to-map similarity, this thesis also presents methodologies for the processing and classification of backscatter data from MBES. In particular, the potential of the combined use of the spatial and angular information of these data for seabed classification is explored through the development of an original segmentation methodology that sequentially divides and aggregates segments defined from a MBES backscatter mosaic on the basis of their angular response content.

text: Quantitative Comparison of Benthic Habitat Maps Derived From Multibeam Echosounder Backscatter Data In the last decade, following the growing concern for the conservation of marine ecosystems, a wide range of approaches has been developed to achieve the identification, classification and mapping of seabed types and of benthic habitats. These approaches, commonly grouped under the denominations of Benthic Habitat Mapping or Acoustic Seabed Classification, exploit the latest scientific and engineering advancements for the exploration of the bottom of the ocean, particularly in underwater acoustics. Among all acoustic seabed-mapping systems available for this purpose, a growing interest has recently developed for Multibeam Echosounders (MBES). This interest is mainly the result of the multiplicity of these systems’ outputs (that is, bathymetry, backscatter mosaic, angular response and water-column data), which allows for multiple approaches to seabed or habitat classification and mapping. While this diversity of mapping approaches and this multiplicity of MBES data products contribute to an increasing quality of the charting of the marine environment, they also unfortunately delay the future standardization of mapping methods, which is required for their effective integration in marine environment management strategies. As a preliminary step towards such standardization, there is a need for generalized efforts of comparison of systems, data products, and mapping approaches, in order to assess the most effective ones given mapping objectives and environment conditions. The main goal of this thesis is to contribute to this effort through the development and implementation of tools and methods for the comparison of categorical seabed or habitat maps, with a specific focus on maps obtained from up-to-date methodologies of classification of MBES backscatter data. This goal is attained through the achievement of specific objectives treated sequentially. First, the need for comparison is justified through a review of the diversity characterizing the fields of Benthic Habitat Mapping and Acoustic Seabed Classification, and of their use of MBES data products. Then, a case study is presented that compare the data products from a Kongsberg EM3000 MBES to the output map of an Acoustic Ground Discrimination Software based on data from a Single-beam Echosounder and to a Sidescan Sonar mosaic, in order to illustrate how map comparison measures could contribute to the comparison of these systems. Next, a number of measures for map-to-map comparison, inspired from the literature in land remote sensing, are presented, along with methodologies for their implementation in comparison of maps described with different legends. The benefit of these measures and methodologies is demonstrated through their application to maps obtained from the acoustic datasets presented previously. Finally, a more typical implementation of these measures is presented as a case study in which the development of two up-to-date classification methodologies of MBES backscatter data is complemented by the quantitative comparison of their output maps. In the process of developing and illustrating the use of methods for the assessment of map-to-map similarity, this thesis also presents methodologies for the processing and classification of backscatter data from MBES. In particular, the potential of the combined use of the spatial and angular information of these data for seabed classification is explored through the development of an original segmentation methodology that sequentially divides and aggregates segments defined from a MBES backscatter mosaic on the basis of their angular response content.

year: 2011

title: Solar wind turbulent heating by interstellar pickup protons: 2-component model

authors: Isenberg, Philip A.

subjects: interstellar pickup ions

abstract: We apply a recently developed 2-component phenomenology to the turbulent heating of the core solar wind protons as seen at the Voyager 2 spacecraft. We find that this new description improves the model predictions of core temperature and correlation scale of the fluctuations, yielding excellent agreement with the Voyager measurements. However, the model fluctuation intensity substantially exceeds the Voyager measurements in the outer heliosphere, indicating that this picture needs further refinement.

text: Solar wind turbulent heating by interstellar pickup protons: 2-component model We apply a recently developed 2-component phenomenology to the turbulent heating of the core solar wind protons as seen at the Voyager 2 spacecraft. We find that this new description improves the model predictions of core temperature and correlation scale of the fluctuations, yielding excellent agreement with the Voyager measurements. However, the model fluctuation intensity substantially exceeds the Voyager measurements in the outer heliosphere, indicating that this picture needs further refinement.

year: 2010

title: Ngā tai e rere nei i waho o Mauao

authors: Ngahuia, Dixon

subjects: Waiata Māori

abstract: "I te ao o ngā tūpuna he maha ngā kaupapa o taua wā i mau ki rō waiata, e whakaata mai ana i ngā kōrero-ā-iwi, ngā taukumekume i waenganui Māori, Pākehā, i waenganui hoki i ngā Māori anō. Nā wai hoki ka puta mai ngā herenga ki waenganui i tēnā iwi, i tēnā hapū, ka whakahoahoa tēnā iwi ki tēnā, te mutunga mai ka whānau ake ngā rōpū hou hei wānanga i ngā kaupapa i manawapātia. I pērā anō hoki ngā iwi o Tauranga Moana, ka huri atu ki tēnei iwi, ki tēnā hei huarahi tautoko āwhina mai i aua kaupapa nei. Ko ngā pupurihanga o ēnei taonga tuku iho e whakaahua mai ana i ngā kaupapa i waenganui i te ao Māori i aua wā, mō te iwi, mō te tangata kotahi rānei. Mā ēnei hoki kitea atu ai tā rātou titiro ki te ao i aua wā. 

He whiringa kōrero tēnei pepa mō tētehi waiata a Ngāi-TeRangi e whakamōhio ake ana i tētehi taukumekume i waenganui i a rāua ko Ngāti Kahungunu. Ka kitea i roto i ngā kōrero ka puta ngā huarahi whakapā atu ai ki tēnā iwi, hapū i waenganui, i waho atu rānei o Ngāi-TeRangi hei āwhina mai i te pupuri mana. Arā anō hoki te whakanui i ēnei momo waiata, ōna mana me te mātauranga Māori e pupū ake ana i konei. 

The waiata of our tūpuna Māori (Māori ancestors) capture in verse many issues and topics that were of significance at the time they were composed. They provide us with snapshots of iwi histories, including accounts of battles between Māori and Pākehā and between Māori and Māori. They tell us of alliances formed and reformed between tribes and hapū and of the reasons for these alliances. We see how the alignment and realignment of kin loyalties related to the issues of the day. Tauranga Moana iwi were not immune to such activities: tribal loyalties were chameleon-like, many alliances being pursued in relation to common interests. The ‘oral mapping’ of these local narratives that we find in waiata provides an illustration of topics relevant to individuals and to iwi: personal and collective statements about the ‘order’ of their day. They provide us with an insight into our ancestors’ ‘ways of seeing the world’. Above all, they are fundamental to the illustration and preservation of Māori knowledge. 
 
This paper presents an analysis of a Ngāi-TeRangi waiata tangi (lament) which relates to activities linking the iwi in a political stance against Ngāti Kahungunu. What is demonstrated is the intricate network of iwi and hapū involvement, within and without Ngāi-TeRangi, in the quest for honour. What is also demonstrated is the importance of waiata as significant literary achievements, as oral treasures."

text: Ngā tai e rere nei i waho o Mauao "I te ao o ngā tūpuna he maha ngā kaupapa o taua wā i mau ki rō waiata, e whakaata mai ana i ngā kōrero-ā-iwi, ngā taukumekume i waenganui Māori, Pākehā, i waenganui hoki i ngā Māori anō. Nā wai hoki ka puta mai ngā herenga ki waenganui i tēnā iwi, i tēnā hapū, ka whakahoahoa tēnā iwi ki tēnā, te mutunga mai ka whānau ake ngā rōpū hou hei wānanga i ngā kaupapa i manawapātia. I pērā anō hoki ngā iwi o Tauranga Moana, ka huri atu ki tēnei iwi, ki tēnā hei huarahi tautoko āwhina mai i aua kaupapa nei. Ko ngā pupurihanga o ēnei taonga tuku iho e whakaahua mai ana i ngā kaupapa i waenganui i te ao Māori i aua wā, mō te iwi, mō te tangata kotahi rānei. Mā ēnei hoki kitea atu ai tā rātou titiro ki te ao i aua wā. 

He whiringa kōrero tēnei pepa mō tētehi waiata a Ngāi-TeRangi e whakamōhio ake ana i tētehi taukumekume i waenganui i a rāua ko Ngāti Kahungunu. Ka kitea i roto i ngā kōrero ka puta ngā huarahi whakapā atu ai ki tēnā iwi, hapū i waenganui, i waho atu rānei o Ngāi-TeRangi hei āwhina mai i te pupuri mana. Arā anō hoki te whakanui i ēnei momo waiata, ōna mana me te mātauranga Māori e pupū ake ana i konei. 

The waiata of our tūpuna Māori (Māori ancestors) capture in verse many issues and topics that were of significance at the time they were composed. They provide us with snapshots of iwi histories, including accounts of battles between Māori and Pākehā and between Māori and Māori. They tell us of alliances formed and reformed between tribes and hapū and of the reasons for these alliances. We see how the alignment and realignment of kin loyalties related to the issues of the day. Tauranga Moana iwi were not immune to such activities: tribal loyalties were chameleon-like, many alliances being pursued in relation to common interests. The ‘oral mapping’ of these local narratives that we find in waiata provides an illustration of topics relevant to individuals and to iwi: personal and collective statements about the ‘order’ of their day. They provide us with an insight into our ancestors’ ‘ways of seeing the world’. Above all, they are fundamental to the illustration and preservation of Māori knowledge. 
 
This paper presents an analysis of a Ngāi-TeRangi waiata tangi (lament) which relates to activities linking the iwi in a political stance against Ngāti Kahungunu. What is demonstrated is the intricate network of iwi and hapū involvement, within and without Ngāi-TeRangi, in the quest for honour. What is also demonstrated is the importance of waiata as significant literary achievements, as oral treasures."

year: 2002-09