title: Analysis of multibeam sonar data for benthic habitat characterization of the Port of Tauranga, New Zealand.

authors: Boulay, Sebastien O. C.

subjects: Tauranga

abstract: Tauranga Harbour is a mesotidal lagoon located within the Bay of Plenty, New Zealand, and is subject to an ongoing maintenance dredging program to remove mud deposits coming from various sources in the catchment. At the southern end of the commercial port, the Tauranga Bridge Marina was built adjacent to the bridge causeway, with 500 floating concrete berths, enclosed by concrete floating breakwaters. It is proposed to convert these floating breakwaters into solid ones to stop waves entering the marina. This is expected to influence tidal circulation around the Tauranga bridge causeway, and potentially affect sedimentation and marine habitats. The region is an important source of "kai moana" (seafood) for local iwi, and is a source of juvenile shellfish for the large beds located on the flood tidal delta and surrounding channels.

This study investigates the impact of the successive harbour constructions on the local sedimentology. The overall goal of the mapping part of this project is to identify and locate the different seabed facies and features within the study site, which may be affected by the sediment transport potentially resulting from the past and future harbour developments. 

To investigate the impacts of the harbour modifications, a habitat-mapping survey using acoustic mapping techniques was undertaken in July and August 2011. The hydrographic survey was simultaneously performed using a multibeam echosounder (Kongsberg-Simrad EM3000) and a Starfish 452F sidescan sonar. The backscatter/imagery data from both systems was then used for habitat mapping, using a combination of Angular Response Analysis and image-based segmentation. An underwater camera survey and seabed sampling were also performed to ground-truth the morphologies identified from the acoustic backscatter analysis. The most recent habitat map was then compared to the previous studies to identify changes in response to the different modifications of the estuary.

text: Analysis of multibeam sonar data for benthic habitat characterization of the Port of Tauranga, New Zealand. Tauranga Harbour is a mesotidal lagoon located within the Bay of Plenty, New Zealand, and is subject to an ongoing maintenance dredging program to remove mud deposits coming from various sources in the catchment. At the southern end of the commercial port, the Tauranga Bridge Marina was built adjacent to the bridge causeway, with 500 floating concrete berths, enclosed by concrete floating breakwaters. It is proposed to convert these floating breakwaters into solid ones to stop waves entering the marina. This is expected to influence tidal circulation around the Tauranga bridge causeway, and potentially affect sedimentation and marine habitats. The region is an important source of "kai moana" (seafood) for local iwi, and is a source of juvenile shellfish for the large beds located on the flood tidal delta and surrounding channels.

This study investigates the impact of the successive harbour constructions on the local sedimentology. The overall goal of the mapping part of this project is to identify and locate the different seabed facies and features within the study site, which may be affected by the sediment transport potentially resulting from the past and future harbour developments. 

To investigate the impacts of the harbour modifications, a habitat-mapping survey using acoustic mapping techniques was undertaken in July and August 2011. The hydrographic survey was simultaneously performed using a multibeam echosounder (Kongsberg-Simrad EM3000) and a Starfish 452F sidescan sonar. The backscatter/imagery data from both systems was then used for habitat mapping, using a combination of Angular Response Analysis and image-based segmentation. An underwater camera survey and seabed sampling were also performed to ground-truth the morphologies identified from the acoustic backscatter analysis. The most recent habitat map was then compared to the previous studies to identify changes in response to the different modifications of the estuary.

year: 2012

title: The new kava user: Diasporic identity formation in reverse

authors: Aporosa, S. 'Apo'

subjects: diaspora

abstract: Diaspora' studies have broadened their definition to now include hybridised identities situated in both the past and future. The formation of the Indo-Fijian ethnicity is an example of the evolution of a hybrid diasporic identity. This article briefly discusses Indo-Fijian diaspora in Fiji before shifting its focus to Aotearoa New Zealand. In this new setting, diaspora understanding will take a new direction that concentrates on the uptake of kava drinking and aspects of the kava culture by some Māori and Pālangi/Pākehā. In doing so, the article examines how these Māori and Pālangi/Pākehā, as the 'hosts', are expanding their cultural identity by embracing an icon of identity that came with a diasporic population – Pasifikans to Aotearoa – essentially creating diasporic identity formation in reverse.

text: The new kava user: Diasporic identity formation in reverse Diaspora' studies have broadened their definition to now include hybridised identities situated in both the past and future. The formation of the Indo-Fijian ethnicity is an example of the evolution of a hybrid diasporic identity. This article briefly discusses Indo-Fijian diaspora in Fiji before shifting its focus to Aotearoa New Zealand. In this new setting, diaspora understanding will take a new direction that concentrates on the uptake of kava drinking and aspects of the kava culture by some Māori and Pālangi/Pākehā. In doing so, the article examines how these Māori and Pālangi/Pākehā, as the 'hosts', are expanding their cultural identity by embracing an icon of identity that came with a diasporic population – Pasifikans to Aotearoa – essentially creating diasporic identity formation in reverse.

year: 2015

title: Design and implementation of an AC voltage regulator based on series power semiconductor array

authors: Vandy, Francis

abstract: This thesis describes the use of an array of power semiconductors (series transistor array) and a buck-boost transformer in the design and implementation of a single phase AC voltage regulator. The power semiconductor array was used to act as variable impedance across the bridge points of a rectifier. The input point of the bridge rectifier was also connected directly to the primary winding of the buck-boost transformer. A closed loop circuit was designed using an RMS/DC converter chip, with complete electrical isolation between the low voltage control circuits and the power circuits. The major advantages of this technique are: fast response to RMS voltage fluctuation; waveform fidelity; light weight; and reduced size compared to that of a servo-driven AC voltage regulator such as the PS10 Smart Power Station, which was used in this project as a benchmark for the AC voltage regulator using the power semiconductor array. The device used for testing the performances of both AC voltage regulators was the NoiseKen VDS-2002 Voltage Dip and Swell Simulator. This simulator was used to perform voltage dip, swell, interruption, and variation tests in a manner fully compliant with IEC 61000 – 4 – 11.

text: Design and implementation of an AC voltage regulator based on series power semiconductor array This thesis describes the use of an array of power semiconductors (series transistor array) and a buck-boost transformer in the design and implementation of a single phase AC voltage regulator. The power semiconductor array was used to act as variable impedance across the bridge points of a rectifier. The input point of the bridge rectifier was also connected directly to the primary winding of the buck-boost transformer. A closed loop circuit was designed using an RMS/DC converter chip, with complete electrical isolation between the low voltage control circuits and the power circuits. The major advantages of this technique are: fast response to RMS voltage fluctuation; waveform fidelity; light weight; and reduced size compared to that of a servo-driven AC voltage regulator such as the PS10 Smart Power Station, which was used in this project as a benchmark for the AC voltage regulator using the power semiconductor array. The device used for testing the performances of both AC voltage regulators was the NoiseKen VDS-2002 Voltage Dip and Swell Simulator. This simulator was used to perform voltage dip, swell, interruption, and variation tests in a manner fully compliant with IEC 61000 – 4 – 11.

year: 2014