title: Computational Nanobiosensing – Drawing Analogies Between Optimisation and Nanobiosensing for Smart Tumour Targeting

authors: Zhang, Lisa

abstract: Nanotechnology has been rapidly developing for early diagnosis and treatment of cancer, with nanoparticles being a large focus. However, traditional drug delivery mechanisms are passive and inefficient, with only 0.7% of nanoparticles reaching the tumour through blood vasculature. In vivo computation, also known as computational nanobiosensing (CONA), replaces nanoparticles with swarms of externally manipulable nanorobots whose movement is controlled by an external actuating system. The biological problem of smart tumour targeting is viewed from the computational perspective as an optimisation problem: nanorobot swarms (computational agents) explore the blood vasculature of high-risk tissue (search space) to locate the tumour (global optimum). Tumour biological gradient fields (BGF) create a fitness landscape, which can be analysed with fitness landscape analysis (FLA) to select and tune appropriate search algorithms for in vivo computation.

Key limitations of previous work for in vivo computation are a lack of realistic BGFs that reflect the tumour microenvironment to test search algorithms on; and for FLA, no available measures that consider physical constraints of the in vivo environment.

Two realistic tumour BGF models were created using COMSOL Multiphysics software (CFD Module), one highly vascularised, the other less vascularised. The vascular architecture was based on in vivo blood vessel networks in healthy and tumour regions, and blood velocity was used as a BGF. Blood velocity was found to be lowest in the tumour region, not exceeding 100 µm/s, confirming its applicability as a BGF for search algorithm testing.

Three new FLA measures were created and validated with numerical simulations on two possible tumour vascular landscapes. These measures addressed the physical constraints of discrete search space, unidirectional blood flow, and nanorobot steering imperfections when using a uniform magnetic field. The less vascularized landscape was found to be more discrete, more heterogeneous, and contain a smaller countercurrent frequency of search direction. This indicated it would be more challenging to solve for than the highly vascularised landscape.

These advancements of the CONA framework allow the in vivo search environment to be better visualised and understood for algorithmic development, as well as provide realistic BGFs to test these search algorithms on.

text: Computational Nanobiosensing – Drawing Analogies Between Optimisation and Nanobiosensing for Smart Tumour Targeting Nanotechnology has been rapidly developing for early diagnosis and treatment of cancer, with nanoparticles being a large focus. However, traditional drug delivery mechanisms are passive and inefficient, with only 0.7% of nanoparticles reaching the tumour through blood vasculature. In vivo computation, also known as computational nanobiosensing (CONA), replaces nanoparticles with swarms of externally manipulable nanorobots whose movement is controlled by an external actuating system. The biological problem of smart tumour targeting is viewed from the computational perspective as an optimisation problem: nanorobot swarms (computational agents) explore the blood vasculature of high-risk tissue (search space) to locate the tumour (global optimum). Tumour biological gradient fields (BGF) create a fitness landscape, which can be analysed with fitness landscape analysis (FLA) to select and tune appropriate search algorithms for in vivo computation.

Key limitations of previous work for in vivo computation are a lack of realistic BGFs that reflect the tumour microenvironment to test search algorithms on; and for FLA, no available measures that consider physical constraints of the in vivo environment.

Two realistic tumour BGF models were created using COMSOL Multiphysics software (CFD Module), one highly vascularised, the other less vascularised. The vascular architecture was based on in vivo blood vessel networks in healthy and tumour regions, and blood velocity was used as a BGF. Blood velocity was found to be lowest in the tumour region, not exceeding 100 µm/s, confirming its applicability as a BGF for search algorithm testing.

Three new FLA measures were created and validated with numerical simulations on two possible tumour vascular landscapes. These measures addressed the physical constraints of discrete search space, unidirectional blood flow, and nanorobot steering imperfections when using a uniform magnetic field. The less vascularized landscape was found to be more discrete, more heterogeneous, and contain a smaller countercurrent frequency of search direction. This indicated it would be more challenging to solve for than the highly vascularised landscape.

These advancements of the CONA framework allow the in vivo search environment to be better visualised and understood for algorithmic development, as well as provide realistic BGFs to test these search algorithms on.

year: 2024

title: To drive, or not to drive: Mode choice in daily commute

authors: Sivasubramaniyam, Rathee Dewi

subjects: Mode choice

abstract: Mode choice for daily commute refers to the process whereby commuters choose a travel mode for their daily trips to work. Despite its ordinary nature, it often involves a series of decisions and consideration of various factors and barriers. More research is needed to understand the various aspects of commuters’ mode choice for daily commute. This thesis comprises three studies that focus on four aspects of mode choice: mode motivating factors, mode commitment, mode decisions, and mode interventions. The thesis aims to present the research gaps that exist in current research related to the four aspects and address them appropriately in the three studies.
The first study sought to identify the motivating factors behind commuters’ mode choices. To address the limitations of investigating only one or two factors and recruiting only a particular type of commuter in a single study, the first study explored the influence of seven psychological factors on five types of commuters’ mode choices. An online survey was distributed to various types of commuters in New Zealand. The results showed that commuters have more than one motivating factor to use their usual modes and some commuters share similar motivating factors.
The first study also aimed to examine how committed commuters are towards their usual modes. To address the limitations of using the categorical measure of modality, the first study involved measuring commuters’ mode commitment using a continuous measure. A 1-week online travel diary was distributed to a subset of the commuters who completed the online questionnaire. The results revealed that the five types of commuters were all committed to their usual modes. However, some of them were more likely to use a combination of more than two modes while others were more likely to use a maximum of two modes for their weekly commutes.
The second study was developed based on the previous findings that all types of commuters were strongly committed towards their usual modes despite having different reasons to use their modes. Thus, the study sought to investigate how commuters decide to use their usual modes for daily commutes by focusing on bounded rationality’s concept of ‘satisficing’ as a decision-making strategy. A sample of New Zealand commuters was invited to complete an online questionnaire. The study found that commuters tend to satisfice when deciding to use their usual modes and commuters with high satisficing tendencies tend to be more positive and satisfied with their regular commutes. 
The third and final study was developed based on assumption that drivers tend to satisfice when deciding to use the car which may explain why current mode-shift interventions have mixed results in terms of their effectiveness. So, the study aimed to test an attitude change intervention known as self-persuasion (i.e., generating arguments to convince oneself) to encourage drivers to reduce their car use. A sample of New Zealand car drivers was invited to complete two online questionnaires and was randomly assigned into one of three conditions (i.e., self-persuasion, direct-persuasion, and control). The study did not find evidence of an effect of self-persuasion on drivers’ car use intentions, behaviours, and attitudes.
Overall, results from the three studies showed the various decisions and factors involved in commuters’ mode choice despite seeming ordinary. The novel approaches used in each study provided new and interesting insights into understanding commuters’ mode choices. The main implication of this thesis is that researchers and policymakers need to take into account these decisions and factors and use various approaches and methods to further understand commuters’ mode choices for their daily commutes and to develop long-lasting mode-shift interventions.

text: To drive, or not to drive: Mode choice in daily commute Mode choice for daily commute refers to the process whereby commuters choose a travel mode for their daily trips to work. Despite its ordinary nature, it often involves a series of decisions and consideration of various factors and barriers. More research is needed to understand the various aspects of commuters’ mode choice for daily commute. This thesis comprises three studies that focus on four aspects of mode choice: mode motivating factors, mode commitment, mode decisions, and mode interventions. The thesis aims to present the research gaps that exist in current research related to the four aspects and address them appropriately in the three studies.
The first study sought to identify the motivating factors behind commuters’ mode choices. To address the limitations of investigating only one or two factors and recruiting only a particular type of commuter in a single study, the first study explored the influence of seven psychological factors on five types of commuters’ mode choices. An online survey was distributed to various types of commuters in New Zealand. The results showed that commuters have more than one motivating factor to use their usual modes and some commuters share similar motivating factors.
The first study also aimed to examine how committed commuters are towards their usual modes. To address the limitations of using the categorical measure of modality, the first study involved measuring commuters’ mode commitment using a continuous measure. A 1-week online travel diary was distributed to a subset of the commuters who completed the online questionnaire. The results revealed that the five types of commuters were all committed to their usual modes. However, some of them were more likely to use a combination of more than two modes while others were more likely to use a maximum of two modes for their weekly commutes.
The second study was developed based on the previous findings that all types of commuters were strongly committed towards their usual modes despite having different reasons to use their modes. Thus, the study sought to investigate how commuters decide to use their usual modes for daily commutes by focusing on bounded rationality’s concept of ‘satisficing’ as a decision-making strategy. A sample of New Zealand commuters was invited to complete an online questionnaire. The study found that commuters tend to satisfice when deciding to use their usual modes and commuters with high satisficing tendencies tend to be more positive and satisfied with their regular commutes. 
The third and final study was developed based on assumption that drivers tend to satisfice when deciding to use the car which may explain why current mode-shift interventions have mixed results in terms of their effectiveness. So, the study aimed to test an attitude change intervention known as self-persuasion (i.e., generating arguments to convince oneself) to encourage drivers to reduce their car use. A sample of New Zealand car drivers was invited to complete two online questionnaires and was randomly assigned into one of three conditions (i.e., self-persuasion, direct-persuasion, and control). The study did not find evidence of an effect of self-persuasion on drivers’ car use intentions, behaviours, and attitudes.
Overall, results from the three studies showed the various decisions and factors involved in commuters’ mode choice despite seeming ordinary. The novel approaches used in each study provided new and interesting insights into understanding commuters’ mode choices. The main implication of this thesis is that researchers and policymakers need to take into account these decisions and factors and use various approaches and methods to further understand commuters’ mode choices for their daily commutes and to develop long-lasting mode-shift interventions.

year: 2021

title: Upsetting Geographies: Sacred Spaces of Matata

authors: Brown, Keri Aroha Michelle

subjects: sacred

abstract: My research focuses on the emotional experience of the unearthing of ancestral bones for local Māori of Matata. The coastal town of Matata in the Eastern Bay of Plenty provides a central case study location as it is a town that is facing the pressure of coastal residential development as well the added strain of dealing with the 2005 flood which has compounded issues over local waahi tapu.  Local iwi have continued to actively advocate for the protection of these sites especially with regard to the ongoing discovery of ancestral bones.

Cultural and emotional geographies provide the theoretical framework for this research. This framework has been particularly useful as it encourages reflexive commentary and alternative ways of approaching and thinking about, and understanding knowledge. I have incorporated the research paradigm of kaupapa Māori which complements my theoretical framework by producing a research design that is organised and shaped according to tikanga Māori while (in) advertently critiquing and challenging traditional ways of conducting research. The overall aim is to explore the current issues surrounding the discovery of ancestral bones through korero with local iwi members. It is through their perspectives, stories, beliefs and opinions that provide a better understanding of the meanings attributed to waahi tapu and the influence of certain events such as the 2005 flood. I examine, critically the relationship between power, sacred sites, bones and the body. 

It is from these objectives that I contribute to an area of scholarship that has been largely left out from geographical enquiry. I suggest that the importance of sacredness and spirituality has been relatively overlooked as an influential factor in people's perceptions of the world around them. This thesis is intended to demonstrate the value of indigenous perspectives of bones, the body and sacredness as a way of better understanding some of the complexities that can arise when cross-cultural approaches collide in environmental planning.  

There are three main themes that have emerged from this research. The first theme has to do with competing knowledges. To Māori, the location and knowledge of ancestral bones is culturally important and is in its self sacred, therefore certain tikanga is applied as a means of a protection mechanism. However this ideologically clashes with traditional scientific western approaches which are privileged over other alternative ways of understanding knowledge, in this case Māori knowledge. The second related theme concerns the process of boundary making and cross-cultural ways of perceiving 'sacred' and 'everyday' spaces. To better understand these perspectives involves acknowledging the embodied and emotional experience of wāhi tapu to Māori, and the active role of kaitiaki in the protection and careful management of these culturally important spaces.

text: Upsetting Geographies: Sacred Spaces of Matata My research focuses on the emotional experience of the unearthing of ancestral bones for local Māori of Matata. The coastal town of Matata in the Eastern Bay of Plenty provides a central case study location as it is a town that is facing the pressure of coastal residential development as well the added strain of dealing with the 2005 flood which has compounded issues over local waahi tapu.  Local iwi have continued to actively advocate for the protection of these sites especially with regard to the ongoing discovery of ancestral bones.

Cultural and emotional geographies provide the theoretical framework for this research. This framework has been particularly useful as it encourages reflexive commentary and alternative ways of approaching and thinking about, and understanding knowledge. I have incorporated the research paradigm of kaupapa Māori which complements my theoretical framework by producing a research design that is organised and shaped according to tikanga Māori while (in) advertently critiquing and challenging traditional ways of conducting research. The overall aim is to explore the current issues surrounding the discovery of ancestral bones through korero with local iwi members. It is through their perspectives, stories, beliefs and opinions that provide a better understanding of the meanings attributed to waahi tapu and the influence of certain events such as the 2005 flood. I examine, critically the relationship between power, sacred sites, bones and the body. 

It is from these objectives that I contribute to an area of scholarship that has been largely left out from geographical enquiry. I suggest that the importance of sacredness and spirituality has been relatively overlooked as an influential factor in people's perceptions of the world around them. This thesis is intended to demonstrate the value of indigenous perspectives of bones, the body and sacredness as a way of better understanding some of the complexities that can arise when cross-cultural approaches collide in environmental planning.  

There are three main themes that have emerged from this research. The first theme has to do with competing knowledges. To Māori, the location and knowledge of ancestral bones is culturally important and is in its self sacred, therefore certain tikanga is applied as a means of a protection mechanism. However this ideologically clashes with traditional scientific western approaches which are privileged over other alternative ways of understanding knowledge, in this case Māori knowledge. The second related theme concerns the process of boundary making and cross-cultural ways of perceiving 'sacred' and 'everyday' spaces. To better understand these perspectives involves acknowledging the embodied and emotional experience of wāhi tapu to Māori, and the active role of kaitiaki in the protection and careful management of these culturally important spaces.

year: 2008