title: Visualising Location-Based Information using Augmented Reality

authors: Zhang, Qimo

subjects: Narrative Navigation

abstract: The use of augmented reality extends navigation in location-based mobile applications. This thesis introduces the concept of narrative navigation and describes the design and testing of four mobile application prototypes that explore the proof-of-concept for narrative navigation. 
We explored the work related to Augmented Reality and navigation and found that no scholars have focused on the use of Augmented Reality by navigating users in the context of location-based stories. This thesis aims to answer the research question of how Augmented Reality visualisations can reflect location-based data to tell a story on mobile devices. While typical navigation only involves guidance to a single point, narrative navigation requires navigation that focuses on the linearity of the story. The goal of our research is to investigate how augmented reality can be used to visualize location-based information for navigation in a storytelling environment.
We carried out the design, development, and testing of the Initial Digital Prototype, exploring the use of Augmented Reality technology to display the Point of Interest (POI) position, direction, distance, and story chapter order, and guide users to the next location in the story. In the subsequent Paper Prototype, we explored four navigation visualisations, showing the next story element through stylized flags of varying heights. We found that showing the next story location nearer to the bottom of the screen was the most successful way to guide users, but also found that many participants preferred to show location order by distance. In the Narrative Navigation Prototype, further POI design options are explored. We improved details such as size, quantity, description and the spacing of POIs, the camera tilt display, and the use of indicator arrows. In the Final Prototype, the concept of narrative navigation was confirmed by the positive evaluation of participants and confirmation of user interactions provided by our behavioural tracking maps that were used to observe participant movements and prototype interactions.
The thesis contributions include four insights into the concept of narrative navigation. The first is the use of augmented reality to visualise location-based stories on mobile phones; the second is to highlight the importance of showing the next location in the story sequence, which has been almost absent in related work. Removing visited story chapters will facilitate navigation and narrative ordering; and finally, the use of directional indicators that guide the small phone screen to connect to the real world.
We have shown that narrative navigation is a promising concept that can expand application scenarios based on location information.

text: Visualising Location-Based Information using Augmented Reality The use of augmented reality extends navigation in location-based mobile applications. This thesis introduces the concept of narrative navigation and describes the design and testing of four mobile application prototypes that explore the proof-of-concept for narrative navigation. 
We explored the work related to Augmented Reality and navigation and found that no scholars have focused on the use of Augmented Reality by navigating users in the context of location-based stories. This thesis aims to answer the research question of how Augmented Reality visualisations can reflect location-based data to tell a story on mobile devices. While typical navigation only involves guidance to a single point, narrative navigation requires navigation that focuses on the linearity of the story. The goal of our research is to investigate how augmented reality can be used to visualize location-based information for navigation in a storytelling environment.
We carried out the design, development, and testing of the Initial Digital Prototype, exploring the use of Augmented Reality technology to display the Point of Interest (POI) position, direction, distance, and story chapter order, and guide users to the next location in the story. In the subsequent Paper Prototype, we explored four navigation visualisations, showing the next story element through stylized flags of varying heights. We found that showing the next story location nearer to the bottom of the screen was the most successful way to guide users, but also found that many participants preferred to show location order by distance. In the Narrative Navigation Prototype, further POI design options are explored. We improved details such as size, quantity, description and the spacing of POIs, the camera tilt display, and the use of indicator arrows. In the Final Prototype, the concept of narrative navigation was confirmed by the positive evaluation of participants and confirmation of user interactions provided by our behavioural tracking maps that were used to observe participant movements and prototype interactions.
The thesis contributions include four insights into the concept of narrative navigation. The first is the use of augmented reality to visualise location-based stories on mobile phones; the second is to highlight the importance of showing the next location in the story sequence, which has been almost absent in related work. Removing visited story chapters will facilitate navigation and narrative ordering; and finally, the use of directional indicators that guide the small phone screen to connect to the real world.
We have shown that narrative navigation is a promising concept that can expand application scenarios based on location information.

year: 2023

title: Investigation into the effects of flow distribution on the photovoltaic performance of a building integrated photovoltaic/thermal solar collector

authors: Ghani, Faisal Abid

subjects: photovoltaic

abstract: The conversion of solar energy into usable forms of energy such as electricity and heat is attractive given the abundance of solar energy and the numerous issues recently raised in the consumption of fossil fuels. Solar conversion technologies may generally be categorised as either photovoltaic or solar thermal types capable of converting incidental sunlight into electricity and heat respectively. The photovoltaic cell is able to transform incidental sunlight into electricity via the Becquerel effect, however, the single junction crystalline silicon solar cell, the predominant cell type in today’s photovoltaic market is only able to utilise a small portion (less than 20%) of incidental sunlight for this purpose. A majority of the remaining portion is absorbed much like a traditional solar thermal collector and sunk as heat by the cell, elevating its operating temperature. Given the negative effect of temperature on photovoltaic cell operation, where a linearly proportional drop in conversion efficiency with elevated temperature can be expected, photovoltaic conversion can be reduced significantly particularly in areas of high irradiance and ambient temperatures. Based on the intrinsic absorption characteristics of the photovoltaic cell, a third type of solar panel referred to as the hybrid photovoltaic thermal collector (PVT) collector has been developed where fluid channels running along the underside of the photovoltaic panel transfer heat away from the cells to minimise this detrimental effect. Furthermore, heat captured from the cells may then be used for space heating or domestic hot water improving the overall collector efficiency.
In this study a unique building integrated PVT (BIPVT) collector is investigated consisting of an aluminium extrusion with structural ribs, fluid channels, and solar conversion materials. In order to evaluate this design, a mathematical model of the collector was developed in order to determine both thermal and electrical yield of the proposed design. The thermal analyses of the building integrated PVT collector in previous studies have generally adopted the approach applied to traditional solar thermal collectors where the distribution of coolant fluid flowing through the piping array is assumed uniform. For a conventional solar thermal collector this simplification may be reasonable under certain circumstances, however, given the temperature sensitivity of photovoltaic cells and their electrical connection scheme, this assumption may lead to significant modelling error. In order to further investigate this issue, a mathematical model has been developed to determine the photovoltaic yield of a BIPVT collector operating under non-homogeneous operating temperature as a result of flow maldistribution. The model is composed of three steps individually addressing the issues of 1) fluid flow, 2) heat transfer, and 3) the photovoltaic output of a BIPVT array. Fluid analysis was conducted using the finite element method in order to obtain the individual fluid channel flow rates. Using these values, a heat transfer analysis was then conducted for each module forming the BIPVT array to calculate the photovoltaic operating temperature for the constituent cells forming the array. During this step the finite difference method was utilised to approximate the fin efficiency of the building integrated collector, taking into account its irregular geometry. Finally the photovoltaic yield was calculated using a numerical approach which considered the individual operating temperature of the PV cells. During this step a new method was identified to determine the values of series and shunt resistances and also the diode constant required for the modelling of photovoltaic devices based on the multi-dimensional Newton-Raphson method and current-voltage equations expressed using the Lambert W-function. Experimentation was carried out to validate the new modelling methods.
These models were combined to quantify the detrimental impact of flow mal-distribution on photovoltaic yield for a number of scenarios. In the case where flow uniformity was poorest, only a 2% improvement in photovoltaic yield was obtained in comparison to a traditional photovoltaic panel operating under the same environmental conditions. For the case where flow uniformity was optimal however, photovoltaic output was improved by almost 10%.
This work has shown that the effects of poor flow distribution has the potential to have a substantial negative impact on the photovoltaic output of a building integrated solar collector especially given the variability in its physical geometry. The appropriate design of this technology should therefore consider the effects of this phenomenon. The methodology presented in this study can be used to approximate PV output for a BIPVT array with different array geometries and operating characteristics. Furthermore, the method to calculate solar cell modelling parameters developed in this study is not only useful for the analysis of hybrid PVT systems, but for the general analysis of photovoltaic systems based on crystalline silicon solar cells.

text: Investigation into the effects of flow distribution on the photovoltaic performance of a building integrated photovoltaic/thermal solar collector The conversion of solar energy into usable forms of energy such as electricity and heat is attractive given the abundance of solar energy and the numerous issues recently raised in the consumption of fossil fuels. Solar conversion technologies may generally be categorised as either photovoltaic or solar thermal types capable of converting incidental sunlight into electricity and heat respectively. The photovoltaic cell is able to transform incidental sunlight into electricity via the Becquerel effect, however, the single junction crystalline silicon solar cell, the predominant cell type in today’s photovoltaic market is only able to utilise a small portion (less than 20%) of incidental sunlight for this purpose. A majority of the remaining portion is absorbed much like a traditional solar thermal collector and sunk as heat by the cell, elevating its operating temperature. Given the negative effect of temperature on photovoltaic cell operation, where a linearly proportional drop in conversion efficiency with elevated temperature can be expected, photovoltaic conversion can be reduced significantly particularly in areas of high irradiance and ambient temperatures. Based on the intrinsic absorption characteristics of the photovoltaic cell, a third type of solar panel referred to as the hybrid photovoltaic thermal collector (PVT) collector has been developed where fluid channels running along the underside of the photovoltaic panel transfer heat away from the cells to minimise this detrimental effect. Furthermore, heat captured from the cells may then be used for space heating or domestic hot water improving the overall collector efficiency.
In this study a unique building integrated PVT (BIPVT) collector is investigated consisting of an aluminium extrusion with structural ribs, fluid channels, and solar conversion materials. In order to evaluate this design, a mathematical model of the collector was developed in order to determine both thermal and electrical yield of the proposed design. The thermal analyses of the building integrated PVT collector in previous studies have generally adopted the approach applied to traditional solar thermal collectors where the distribution of coolant fluid flowing through the piping array is assumed uniform. For a conventional solar thermal collector this simplification may be reasonable under certain circumstances, however, given the temperature sensitivity of photovoltaic cells and their electrical connection scheme, this assumption may lead to significant modelling error. In order to further investigate this issue, a mathematical model has been developed to determine the photovoltaic yield of a BIPVT collector operating under non-homogeneous operating temperature as a result of flow maldistribution. The model is composed of three steps individually addressing the issues of 1) fluid flow, 2) heat transfer, and 3) the photovoltaic output of a BIPVT array. Fluid analysis was conducted using the finite element method in order to obtain the individual fluid channel flow rates. Using these values, a heat transfer analysis was then conducted for each module forming the BIPVT array to calculate the photovoltaic operating temperature for the constituent cells forming the array. During this step the finite difference method was utilised to approximate the fin efficiency of the building integrated collector, taking into account its irregular geometry. Finally the photovoltaic yield was calculated using a numerical approach which considered the individual operating temperature of the PV cells. During this step a new method was identified to determine the values of series and shunt resistances and also the diode constant required for the modelling of photovoltaic devices based on the multi-dimensional Newton-Raphson method and current-voltage equations expressed using the Lambert W-function. Experimentation was carried out to validate the new modelling methods.
These models were combined to quantify the detrimental impact of flow mal-distribution on photovoltaic yield for a number of scenarios. In the case where flow uniformity was poorest, only a 2% improvement in photovoltaic yield was obtained in comparison to a traditional photovoltaic panel operating under the same environmental conditions. For the case where flow uniformity was optimal however, photovoltaic output was improved by almost 10%.
This work has shown that the effects of poor flow distribution has the potential to have a substantial negative impact on the photovoltaic output of a building integrated solar collector especially given the variability in its physical geometry. The appropriate design of this technology should therefore consider the effects of this phenomenon. The methodology presented in this study can be used to approximate PV output for a BIPVT array with different array geometries and operating characteristics. Furthermore, the method to calculate solar cell modelling parameters developed in this study is not only useful for the analysis of hybrid PVT systems, but for the general analysis of photovoltaic systems based on crystalline silicon solar cells.

year: 2013

title: Bicultural challenges for educational professionals in Aotearoa

authors: Glynn, Ted

abstract: As educational professionals in New Zealand at the approach of the twenty-first century, some 158 years after the Treaty of Waitangi, we face some major challenges in examining our bicultural goals and achievements. In this paper I explore some of these goals and achievements which I believe must be addressed in our pedagogical practice and in our educational research.

text: Bicultural challenges for educational professionals in Aotearoa As educational professionals in New Zealand at the approach of the twenty-first century, some 158 years after the Treaty of Waitangi, we face some major challenges in examining our bicultural goals and achievements. In this paper I explore some of these goals and achievements which I believe must be addressed in our pedagogical practice and in our educational research.

year: 2015