title: A calibrated dual-port acoustic Vector Network Analyser

authors: MacDonell, Marcus Scott Glengarry

subjects: VNA

abstract: The Vector Network Analyzer (VNA) is a workhorse in electrical engineering, and has been refined over the last fifty years to offer many advantages. This technology is continually expanding and branching into other fields including optics. This thesis presents the design and calibration of an Acoustic Vector Network Analyzer (AVNA), which represents further adaptation of this technology into other engineering fields. This goal requires several developments; a repeatable acoustic waveguide flange/joint, a calibration method(s), calibration standards, and calibration verification.

The hardware that has been developed is used as an accessory to an existing commercial VNA mainframe (Agilent-4395A) and a retrofitted test-set (HP87511A) that now hosts connectivity for our ``measurement heads'' containing the acoustic directional couplers. Directional couplers are the fundamental technology that allows for Vector Network Analysis, the acoustic variant has an operational range of a little more than an octave and sufficient directionality for calibration. The coupler is a branch waveguide coupler and to enable reliable and repeatable connection has been equipped with a flange system. This flange system has alignment pins and O-rings to ensure proper sealing and repeatability. Several materials were used with additive manufacturing techniques to create couplers and waveguide sections, each with its own advantages. Titanium (Ti64) offered the best usability and reliability, while plastic offered better repeatability.

Calibration was a major advance in the VNA and one that popularized the instrument. The calibration's performance is limited by the repeatability of flanged joints. This is because several measurements are required to produce a linear system of equations, therefore this system contains within it the variation of the flange joints. 

Developing a calibration method is the crux in realizing the aim of an Acoustic VNA. This thesis presents a set of five measurements and two competing algorithms that can be used to implement calibration. The analytical and numerical methods presented both have distinct advantages and disadvantages. The five measurements are performed with proposed calibration standards. A ``Thru'', ``Reflect'' and ``Match'' standard are required. The ``Match'' standard is provided by a sliding load, the sliding load has been previously used as part of an acoustic calibration. To verify the operation of the calibrated instrument verification measurement was performed using a passive, asymmetrical, reciprocal device (PARD).

text: A calibrated dual-port acoustic Vector Network Analyser The Vector Network Analyzer (VNA) is a workhorse in electrical engineering, and has been refined over the last fifty years to offer many advantages. This technology is continually expanding and branching into other fields including optics. This thesis presents the design and calibration of an Acoustic Vector Network Analyzer (AVNA), which represents further adaptation of this technology into other engineering fields. This goal requires several developments; a repeatable acoustic waveguide flange/joint, a calibration method(s), calibration standards, and calibration verification.

The hardware that has been developed is used as an accessory to an existing commercial VNA mainframe (Agilent-4395A) and a retrofitted test-set (HP87511A) that now hosts connectivity for our ``measurement heads'' containing the acoustic directional couplers. Directional couplers are the fundamental technology that allows for Vector Network Analysis, the acoustic variant has an operational range of a little more than an octave and sufficient directionality for calibration. The coupler is a branch waveguide coupler and to enable reliable and repeatable connection has been equipped with a flange system. This flange system has alignment pins and O-rings to ensure proper sealing and repeatability. Several materials were used with additive manufacturing techniques to create couplers and waveguide sections, each with its own advantages. Titanium (Ti64) offered the best usability and reliability, while plastic offered better repeatability.

Calibration was a major advance in the VNA and one that popularized the instrument. The calibration's performance is limited by the repeatability of flanged joints. This is because several measurements are required to produce a linear system of equations, therefore this system contains within it the variation of the flange joints. 

Developing a calibration method is the crux in realizing the aim of an Acoustic VNA. This thesis presents a set of five measurements and two competing algorithms that can be used to implement calibration. The analytical and numerical methods presented both have distinct advantages and disadvantages. The five measurements are performed with proposed calibration standards. A ``Thru'', ``Reflect'' and ``Match'' standard are required. The ``Match'' standard is provided by a sliding load, the sliding load has been previously used as part of an acoustic calibration. To verify the operation of the calibrated instrument verification measurement was performed using a passive, asymmetrical, reciprocal device (PARD).

year: 2022

title: Perceptions of Chinese traditional food and European food among Chinese consumers

authors: Wang, Ou

subjects: Science & Technology

abstract: Purpose
The purpose of this paper is to explore Chinese consumers’ perceptions in relation to both Chinese traditional and European food.

Design/methodology/approach
A web-based free word association test was administered to 302 consumers in China. They were asked to give the first three words that came into their minds when they were presented with each of two stimulus words, “traditional food” and “European food”. Three researchers grouped the elicited words into classes and then into dimensions. χ2 association tests were used to assess and identify statistically significant differences in the frequencies of classes and dimensions for the two food concepts between socio-demographic groups.

Findings
The findings show that Chinese consumers define Chinese traditional food and European food through ten similar dimensions: Sensory appeal, Health, Origin, Marketing, Safety, Variety, Heritage, Symbolic meaning, Simplicity and Mood. Additionally, they associate Chinese traditional food with the dimensions Elaboration, Celebration and Habit, as well as link European food to the dimensions Convenience and New. Although ten dimensions are the same, obvious differences can be identified by comparing the classes for the two food concepts. Further, there are significant differences in the class associations for European food between age groups and in the dimension associations for Chinese traditional food between gender groups.

Originality/value
By using an online qualitative research method, this study is one of the first to address how Chinese consumers define both European food and their own traditional food in China, the largest East Asian country. The findings are particularly useful for the future development of traditional food products and for the future export of European food products onto China and even other countries in East Asia.

text: Perceptions of Chinese traditional food and European food among Chinese consumers Purpose
The purpose of this paper is to explore Chinese consumers’ perceptions in relation to both Chinese traditional and European food.

Design/methodology/approach
A web-based free word association test was administered to 302 consumers in China. They were asked to give the first three words that came into their minds when they were presented with each of two stimulus words, “traditional food” and “European food”. Three researchers grouped the elicited words into classes and then into dimensions. χ2 association tests were used to assess and identify statistically significant differences in the frequencies of classes and dimensions for the two food concepts between socio-demographic groups.

Findings
The findings show that Chinese consumers define Chinese traditional food and European food through ten similar dimensions: Sensory appeal, Health, Origin, Marketing, Safety, Variety, Heritage, Symbolic meaning, Simplicity and Mood. Additionally, they associate Chinese traditional food with the dimensions Elaboration, Celebration and Habit, as well as link European food to the dimensions Convenience and New. Although ten dimensions are the same, obvious differences can be identified by comparing the classes for the two food concepts. Further, there are significant differences in the class associations for European food between age groups and in the dimension associations for Chinese traditional food between gender groups.

Originality/value
By using an online qualitative research method, this study is one of the first to address how Chinese consumers define both European food and their own traditional food in China, the largest East Asian country. The findings are particularly useful for the future development of traditional food products and for the future export of European food products onto China and even other countries in East Asia.

year: 2016

title: “It’s becoming part of their knowing”: a study of bicultural development in an early childhood teacher education setting in Aotearoa/New Zealand

authors: Ritchie, Jenny

abstract: This study is an exploration of the implementation of bicultural development within a university-based early childhood teacher education programme in Aotearoa/New Zealand, which can be considered to be a bicultural country (Walker, 1987, p. 221). Bicultural development is a process in line with obligations contained within the Te Tiriti o Waitangi/The Treaty of Waitangi, which are reflected within the New Zealand Ministry of Education’s Revised Statement of Desirable Objectives and Practices (Ministry of Education, 1996a) and the early childhood curriculum, Te Whāriki (Ministry of Education, 1996b). The study adopts a critical, transformative theoretical paradigm, and employed an eclectic and emergent qualitative methodological approach, that reflected aspects from ethnographic, narrative and grounded theory methodologies. Interviews with university lecturers, early childhood care and education teachers, and professional development facilitators within the early childhood field; observations within early childhood care and education centres; audio taping of university class discussions; samples of university student assignments; and a written survey of graduates of the university teacher education programme provide the sources of data for the study. Central to the methodological process is a commitment to ethical care for participants, which involves attentive accountability to the interpretations that they place on the material that they contribute to the study and to the overall theorising of the significance of the findings. 

Key research questions of the study were to define ‘bicultural development’ in the context of early childhood care and education in this country; to identify key components of the bicultural development implementation process employed within the university teacher early childhood education programme; to distinguish some useful ‘indicators’ of bicultural development within early childhood centres; and to consider the implications for the teacher education programme in terms of preparing graduates to facilitate bicultural development within their future work in early childhood education. 

A significant finding of the study was the identification of a range of strategies for implementing bicultural development in early childhood education teacher education and care and education settings. The key strategies include Tiriti-based partnership models of teaching whereby Māori and Pākehā work alongside each other, enabling the paralleling of Māori and Western perspectives within both university teacher education and early childhood care and education programmes. It was considered essential that universities employ Māori lecturers to enable Māori content within the teacher education programme to be adequately provisioned. Since there are few Māori educators employed in mainstream early childhood services, it was suggested that teachers might seek to employ a “whanaungatanga” approach. This involves the early childhood centre staff creating a climate and environment in which Māori families/whānau are comfortable to participate fully in programme planning, implementation, and evaluation, which will enable all children attending to access Māori perspectives alongside the Western curriculum content. This approach is consistent with Article Two of Te Tiriti o Waitangi, which guaranteed to Māori their tino rangatiratanga, or self-determination. 

An implication for management and staff of early childhood teacher education programmes in Aotearoa/New Zealand is the need to equip graduates with the knowledge bases and commitment that will enable them to implement bicultural development, ideally through adopting, a whanaungatanga approach. This involves facilitating teacher education students to move beyond the dysconscious racism (King, 1994) that is deeply embedded in mainstream Pākehā culture in this country, to the position where they are able to adopt a critical, transformative stance that is humble, respectful and responsive to cultural difference. This stance includes valuing the inclusion of te reo me ōna tikanga throughout early childhood programmes, in a partnership initiated by teachers, but one in which whānau Māori are then able to take the lead in determining the nature and application of Māori content.

text: “It’s becoming part of their knowing”: a study of bicultural development in an early childhood teacher education setting in Aotearoa/New Zealand This study is an exploration of the implementation of bicultural development within a university-based early childhood teacher education programme in Aotearoa/New Zealand, which can be considered to be a bicultural country (Walker, 1987, p. 221). Bicultural development is a process in line with obligations contained within the Te Tiriti o Waitangi/The Treaty of Waitangi, which are reflected within the New Zealand Ministry of Education’s Revised Statement of Desirable Objectives and Practices (Ministry of Education, 1996a) and the early childhood curriculum, Te Whāriki (Ministry of Education, 1996b). The study adopts a critical, transformative theoretical paradigm, and employed an eclectic and emergent qualitative methodological approach, that reflected aspects from ethnographic, narrative and grounded theory methodologies. Interviews with university lecturers, early childhood care and education teachers, and professional development facilitators within the early childhood field; observations within early childhood care and education centres; audio taping of university class discussions; samples of university student assignments; and a written survey of graduates of the university teacher education programme provide the sources of data for the study. Central to the methodological process is a commitment to ethical care for participants, which involves attentive accountability to the interpretations that they place on the material that they contribute to the study and to the overall theorising of the significance of the findings. 

Key research questions of the study were to define ‘bicultural development’ in the context of early childhood care and education in this country; to identify key components of the bicultural development implementation process employed within the university teacher early childhood education programme; to distinguish some useful ‘indicators’ of bicultural development within early childhood centres; and to consider the implications for the teacher education programme in terms of preparing graduates to facilitate bicultural development within their future work in early childhood education. 

A significant finding of the study was the identification of a range of strategies for implementing bicultural development in early childhood education teacher education and care and education settings. The key strategies include Tiriti-based partnership models of teaching whereby Māori and Pākehā work alongside each other, enabling the paralleling of Māori and Western perspectives within both university teacher education and early childhood care and education programmes. It was considered essential that universities employ Māori lecturers to enable Māori content within the teacher education programme to be adequately provisioned. Since there are few Māori educators employed in mainstream early childhood services, it was suggested that teachers might seek to employ a “whanaungatanga” approach. This involves the early childhood centre staff creating a climate and environment in which Māori families/whānau are comfortable to participate fully in programme planning, implementation, and evaluation, which will enable all children attending to access Māori perspectives alongside the Western curriculum content. This approach is consistent with Article Two of Te Tiriti o Waitangi, which guaranteed to Māori their tino rangatiratanga, or self-determination. 

An implication for management and staff of early childhood teacher education programmes in Aotearoa/New Zealand is the need to equip graduates with the knowledge bases and commitment that will enable them to implement bicultural development, ideally through adopting, a whanaungatanga approach. This involves facilitating teacher education students to move beyond the dysconscious racism (King, 1994) that is deeply embedded in mainstream Pākehā culture in this country, to the position where they are able to adopt a critical, transformative stance that is humble, respectful and responsive to cultural difference. This stance includes valuing the inclusion of te reo me ōna tikanga throughout early childhood programmes, in a partnership initiated by teachers, but one in which whānau Māori are then able to take the lead in determining the nature and application of Māori content.

year: 2002