title: Implementation aspects and offline digital signal processing of a smart pebble for river bed sediment transport monitoring

authors: Kularatna, Nihal

subjects: smart pebble

abstract: Conceptualization aspects of a smart sediment particle (smart pebble) for monitoring of sediment transport in riverbeds have been documented previously [1]. However, this mixed signal approach was done only at a conceptual level and lacks complete implementation aspects such as limited PCB real estate, a miniaturized power source and adequately addressing the offset errors. A fully digital version with multiple strap-down MEMs, signal conditioning blocks, an 8-bit processor and a memory subsystem was designed and assembled within a less than 4 cm diameter sphere to allow data capture for up to 15 minutes. This compact subsystem allows exporting of output data, stored within the memory from nine sampled MEM sensors, into an offline-processing environment for further processing to generate essential motion information. Complex mathematical algorithms for axis conversion, etc, are housed within the offline-processing environment reducing the burden on the smart pebble. The total electronic subsystem embedded within the pebble together with the external processing algorithms tackle cumulative errors, gravitational compensation requirements and offset errors, while being powered by a specially designed power stage, based on a single alkaline cell.

text: Implementation aspects and offline digital signal processing of a smart pebble for river bed sediment transport monitoring Conceptualization aspects of a smart sediment particle (smart pebble) for monitoring of sediment transport in riverbeds have been documented previously [1]. However, this mixed signal approach was done only at a conceptual level and lacks complete implementation aspects such as limited PCB real estate, a miniaturized power source and adequately addressing the offset errors. A fully digital version with multiple strap-down MEMs, signal conditioning blocks, an 8-bit processor and a memory subsystem was designed and assembled within a less than 4 cm diameter sphere to allow data capture for up to 15 minutes. This compact subsystem allows exporting of output data, stored within the memory from nine sampled MEM sensors, into an offline-processing environment for further processing to generate essential motion information. Complex mathematical algorithms for axis conversion, etc, are housed within the offline-processing environment reducing the burden on the smart pebble. The total electronic subsystem embedded within the pebble together with the external processing algorithms tackle cumulative errors, gravitational compensation requirements and offset errors, while being powered by a specially designed power stage, based on a single alkaline cell.

year: 2006

title: Distributed Operating Systems on Wireless Sensor Networks

authors: Hunkin, Paul Wade

subjects: Wireless Sensor Networks

abstract: This thesis proposes the use of traditional distributed operating system and distributed systems techniques that are adapted and applied to the wireless sensor network domain. These techniques are applied to the creation of a wireless sensor network operating system that allows complex applications to be created without special programmer knowledge of sensor network programming or architecture. The resulting system is capable of executing a high level user application written in conventional single-system-image form, without the user being aware of the mesh architecture or underlying sensor node hardware.

A wireless sensor network is a collection of battery-powered embedded systems that communicate over low-bandwidth radio. Because of their limited hardware, niche deployments and use of embedded processors, programming techniques for wireless sensor network nodes are generally relatively esoteric compared to most software programming tasks. This can be relatively complex for programmers not familiar with the wireless sensor network domain. A naive approach to writing a wireless sensor network application may well result in considerably reduced battery life due to inefficient use of the limited power resources, requiring an expensive and time-consuming replacement or patching process. 

As a result of this complexity, traditional wireless sensor network applications are written as simply as possible. The majority of these applications simply move passive data readings back across a mesh to a more powerful server. While this is a sufficiently effective approach in some situations, for other sensor network deployments involving large amounts of complex data it is more efficient for the sensor network application to process at least some of the data inside the mesh, saving on unnecessary data transmissions. However in the real world, the complexity of writing such an application in many cases precludes this from being created. An operating system that provides power-efficient distributed processing while presenting a more standard unified single system image to the application developer would provide new possibilities for sensor network application developers in terms of creating dynamic and complex sensor network applications. 

This thesis covers the design decisions, development process and evaluation of the Hydra distributed wireless sensor network operating system, an operating system that provides these services. The system is evaluated in the form of a scenario for monitoring intruders over a large area using accelerometer monitoring -- during this scenario, power efficiency is gained due to the intelligent Hydra operating system services, as the resulting accelerometer data is not moved across potentially multi-hop network links. Application code complexity is also reduced due to the higher-level single system image programming environment.

text: Distributed Operating Systems on Wireless Sensor Networks This thesis proposes the use of traditional distributed operating system and distributed systems techniques that are adapted and applied to the wireless sensor network domain. These techniques are applied to the creation of a wireless sensor network operating system that allows complex applications to be created without special programmer knowledge of sensor network programming or architecture. The resulting system is capable of executing a high level user application written in conventional single-system-image form, without the user being aware of the mesh architecture or underlying sensor node hardware.

A wireless sensor network is a collection of battery-powered embedded systems that communicate over low-bandwidth radio. Because of their limited hardware, niche deployments and use of embedded processors, programming techniques for wireless sensor network nodes are generally relatively esoteric compared to most software programming tasks. This can be relatively complex for programmers not familiar with the wireless sensor network domain. A naive approach to writing a wireless sensor network application may well result in considerably reduced battery life due to inefficient use of the limited power resources, requiring an expensive and time-consuming replacement or patching process. 

As a result of this complexity, traditional wireless sensor network applications are written as simply as possible. The majority of these applications simply move passive data readings back across a mesh to a more powerful server. While this is a sufficiently effective approach in some situations, for other sensor network deployments involving large amounts of complex data it is more efficient for the sensor network application to process at least some of the data inside the mesh, saving on unnecessary data transmissions. However in the real world, the complexity of writing such an application in many cases precludes this from being created. An operating system that provides power-efficient distributed processing while presenting a more standard unified single system image to the application developer would provide new possibilities for sensor network application developers in terms of creating dynamic and complex sensor network applications. 

This thesis covers the design decisions, development process and evaluation of the Hydra distributed wireless sensor network operating system, an operating system that provides these services. The system is evaluated in the form of a scenario for monitoring intruders over a large area using accelerometer monitoring -- during this scenario, power efficiency is gained due to the intelligent Hydra operating system services, as the resulting accelerometer data is not moved across potentially multi-hop network links. Application code complexity is also reduced due to the higher-level single system image programming environment.

year: 2017

title: Virtual hākari:  Sharing Māori culinary traditions in online communities

authors: Muru-Lanning, Charlotte

subjects: Kai Māori

abstract: For Māori, kai is a vital expression of identity, community, place and whakapapa. Traditionally, knowledge about kai is transmitted through customary community groupings and culturally embedded practices. However, with the rise of digital platforms, new spaces have emerged for Māori to gather and to share kai in virtual forms. 
This thesis observes how two Facebook groups – Kai Maori and KAI Basket NZ – operate as contemporary spaces for the transmission of Māori culinary knowledge and cultural identity. Kai Māori is considered alongside global studies of culinary traditions and understood through the notion of kai as whakapapa. The thesis addresses two core research questions: 1) How do Facebook groups contribute to an evolving concept of kai Māori? and 2) What kinds of relationships define these online kai communities? 
Guided by Māori data sovereignty (MDSov) principles, I observed interactions on both Facebook pages in two phases – one involving selective data collection over a twelve-month period from January to December 2024 the other involving systematic data collection over a four-week period from 10 December 2024 to 10 January 2025. The observation periods yielded 115 and 1293 posts respectively. A covert digital approach of ‘lurking’ was adopted as seeking prior consent may have affected the quality of the data and disrupted group dynamics. Lurking, as a method, sits uneasily alongside MDSov principles, particularly the principle of manaakitanga, requiring free, prior and informed consent. To address this I safeguarded the confidentiality of community members by seeking consent before reproducing content, removing group members’ names and excluding sensitive information. To analyse posts I used Ethnographic Content Analysis which allowed me to conduct a reflexive, iterative analysis of the posts in a way that was sensitive to the context in which the content was created.
These digital observations show that these groups serve as platforms for the transmission and innovation of kai Māori, encompassing edible components as well as the values enmeshed within these culinary traditions. Despite the mediated nature of these exchanges – where food is virtually consumed rather than physically shared, separate from traditional notions of community – these groups nurture meaningful connections among members, including those physically distant from their whenua. Through recipes, photos, stories, and commentary, the members of Kai Maori and KAI Basket NZ cultivate community identity and belonging via common cultural understandings, sharing of knowledge, a general spirit of sociality – and, importantly, a mutual love of kai.
I conceptualise these online spaces as virtual hākari, where the act of sharing virtual kai becomes an affirmation of identity and a form of cultural resistance. While online sharing may risk distancing kai practices and knowledge from traditional sites of transmission, the data suggests that these platforms may serve as conduits that encourage deeper cultural engagement offline. This thesis highlights the centrality of food in Māori cultural survival, sovereignty and resistance. In these digital spaces, kai Māori is not only celebrated but continually reimagined – reinforcing that to prepare, share and celebrate kai as Māori is to actively participate in the continuity of cultural identity.

text: Virtual hākari:  Sharing Māori culinary traditions in online communities For Māori, kai is a vital expression of identity, community, place and whakapapa. Traditionally, knowledge about kai is transmitted through customary community groupings and culturally embedded practices. However, with the rise of digital platforms, new spaces have emerged for Māori to gather and to share kai in virtual forms. 
This thesis observes how two Facebook groups – Kai Maori and KAI Basket NZ – operate as contemporary spaces for the transmission of Māori culinary knowledge and cultural identity. Kai Māori is considered alongside global studies of culinary traditions and understood through the notion of kai as whakapapa. The thesis addresses two core research questions: 1) How do Facebook groups contribute to an evolving concept of kai Māori? and 2) What kinds of relationships define these online kai communities? 
Guided by Māori data sovereignty (MDSov) principles, I observed interactions on both Facebook pages in two phases – one involving selective data collection over a twelve-month period from January to December 2024 the other involving systematic data collection over a four-week period from 10 December 2024 to 10 January 2025. The observation periods yielded 115 and 1293 posts respectively. A covert digital approach of ‘lurking’ was adopted as seeking prior consent may have affected the quality of the data and disrupted group dynamics. Lurking, as a method, sits uneasily alongside MDSov principles, particularly the principle of manaakitanga, requiring free, prior and informed consent. To address this I safeguarded the confidentiality of community members by seeking consent before reproducing content, removing group members’ names and excluding sensitive information. To analyse posts I used Ethnographic Content Analysis which allowed me to conduct a reflexive, iterative analysis of the posts in a way that was sensitive to the context in which the content was created.
These digital observations show that these groups serve as platforms for the transmission and innovation of kai Māori, encompassing edible components as well as the values enmeshed within these culinary traditions. Despite the mediated nature of these exchanges – where food is virtually consumed rather than physically shared, separate from traditional notions of community – these groups nurture meaningful connections among members, including those physically distant from their whenua. Through recipes, photos, stories, and commentary, the members of Kai Maori and KAI Basket NZ cultivate community identity and belonging via common cultural understandings, sharing of knowledge, a general spirit of sociality – and, importantly, a mutual love of kai.
I conceptualise these online spaces as virtual hākari, where the act of sharing virtual kai becomes an affirmation of identity and a form of cultural resistance. While online sharing may risk distancing kai practices and knowledge from traditional sites of transmission, the data suggests that these platforms may serve as conduits that encourage deeper cultural engagement offline. This thesis highlights the centrality of food in Māori cultural survival, sovereignty and resistance. In these digital spaces, kai Māori is not only celebrated but continually reimagined – reinforcing that to prepare, share and celebrate kai as Māori is to actively participate in the continuity of cultural identity.

year: 2025