title: Techniques for Failure Recovery in a Software-Defined Network

authors: Lorier, Christopher Martin

subjects: Software-Defined Networking

abstract: As our lives become ever more dependent on network connectivity, it becomes increasingly more important for networks to be able to overcome the failure of individual components and continue to function. This thesis examines approaches to fault tolerance in software defined networks, and how the global viewpoint that Software-Defined Networking provides can be leveraged to create more reliable networks.

In order to continue operation after the failure of a network component, the failure must first be detected, and then the network must automatically change its behaviour to mitigate any adverse consequences.  This thesis evaluates a variety of fault detection methods and potential responses. Based on these evaluations the design for a fault tolerance system for software defined networks is presented. This system builds protected paths using Ring Based Forwarding, an algorithm for creating a full mesh of paths between switches in a network where each path has a fail-over path at each hop. The system monitors the network for faults using Traffic Colouring, a technique for passively monitoring network traffic.

text: Techniques for Failure Recovery in a Software-Defined Network As our lives become ever more dependent on network connectivity, it becomes increasingly more important for networks to be able to overcome the failure of individual components and continue to function. This thesis examines approaches to fault tolerance in software defined networks, and how the global viewpoint that Software-Defined Networking provides can be leveraged to create more reliable networks.

In order to continue operation after the failure of a network component, the failure must first be detected, and then the network must automatically change its behaviour to mitigate any adverse consequences.  This thesis evaluates a variety of fault detection methods and potential responses. Based on these evaluations the design for a fault tolerance system for software defined networks is presented. This system builds protected paths using Ring Based Forwarding, an algorithm for creating a full mesh of paths between switches in a network where each path has a fail-over path at each hop. The system monitors the network for faults using Traffic Colouring, a technique for passively monitoring network traffic.

year: 2014

title: Thai Students’ Understanding about Celestial Motion within Their Social and Cultural Context

authors: Anatasook, Sakanan

abstract: This study investigated forty-one Thai 9th grade students’ understanding about the motion of the sun, moon, and stars within their social and cultural context. Students' understanding was explored using a survey tool titled “Students’ Understanding about Celestial Motion within Their Social and Cultural Context Questionnaire (SCMSCQ).” This questionnaire gave students the opportunity to express their ideas about celestial motion within their social and cultural context. The study reveals some interesting features of student understanding, and particularly their difficulty in perceiving the relationship between the study of celestial motion and their social and cultural context. Many students used descriptions from their everyday observations of the daily motion of the sun, moon, and stars, rather than scientific explanations, to answer questions about the relationship between social and cultural context and celestial motion. This study has implications for the development of teaching the sociocultural approach in Thailand.

text: Thai Students’ Understanding about Celestial Motion within Their Social and Cultural Context This study investigated forty-one Thai 9th grade students’ understanding about the motion of the sun, moon, and stars within their social and cultural context. Students' understanding was explored using a survey tool titled “Students’ Understanding about Celestial Motion within Their Social and Cultural Context Questionnaire (SCMSCQ).” This questionnaire gave students the opportunity to express their ideas about celestial motion within their social and cultural context. The study reveals some interesting features of student understanding, and particularly their difficulty in perceiving the relationship between the study of celestial motion and their social and cultural context. Many students used descriptions from their everyday observations of the daily motion of the sun, moon, and stars, rather than scientific explanations, to answer questions about the relationship between social and cultural context and celestial motion. This study has implications for the development of teaching the sociocultural approach in Thailand.

year: 2015

title: Toi tu te whenua, toi tu te tangata: A holistic Māori approach to flood management in Pawarenga

authors: Proctor, Elizabeth-Mary

subjects: flood management

abstract: This thesis is a study of how tikanga Māori principles could be used in practice in the management of natural hazards and in particular flooding in a rural area, Pawarenga. The aim was to investigate and document Te Uri O Tai Hapū preferred strategies for reducing flood risk in Pawarenga and to consider opportunities to use tikanga Māori principles and values in emergency response. The identification of key concepts and principles of tikanga Māori customs and their connections to whānau and hapū of Te Uri O Tai is key to this study. I used kaupapa Māori research methodologies as a guiding framework since researching in my own community required me to manage accountability both to its members and to the university. In particular it was important to obtain permission from the community before beginning, to ensure my research processes were acceptable, and to return my findings to the community. Qualitative data was gathered from a series of hui and interviews with local community members. Data was analysed inductively and organised into thematic networks. Two major organising themes were identified: resilience and vulnerability. Participants described a broad range of strengths inherent in the community that enabled them to respond to crises such as flood events. A number of cultural, social, physical, economic and political vulnerabilities were also identified; most of these were fundamental aspects of people‘s daily lives and did not prevent them from responding positively when floods occurred, but may have limited the scope of their responses. Tikanga was not a subject that participants felt comfortable talking about, but from the descriptions of how people actually responded during floods I was able to see examples of how tikanga was used. The resilience of the Pawarenga community is taken for granted by residents. When disasters such as floods occur, their resiliencies and strengths are brought into play to ensure the safety of all in the community. Tikanga Māori is an inherent part of this resiliency, and marae structures and protocols already in place provide a vital framework for flood response. I conclude that tikanga already has enormous value in flood response, and for Māori communities is an obvious choice as a foundation for a flood emergency management strategy. Furthermore, the value of tikanga as a flood emergency management strategy should be more explicitly recognised and supported by all authorities involved in disaster response and management. It was also clear that multiple dimensions of vulnerability (physical, cultural, social, economic and political) affect the Pawarenga community, and to some extent limit their capacity to respond. In particular political processes that exclude them from participating in decision-making and planning around environmental management generally have left people feeling marginalised, since they are unable to fulfil their kaitiaki role. With civil defence emergency management policies explicitly focused around resilience, participation of Te Uri O Tai Hapū in planning for emergency management should allow for their existing resilience, which stems from the upholding of tikanga, to be recognised and strengthened. However, this will only happen if relationships with the various authorities involved in emergency and natural hazard response are fostered, full participation in decision-making and in responding to natural hazard events is facilitated, and resources are available to support the community with their endeavours.

text: Toi tu te whenua, toi tu te tangata: A holistic Māori approach to flood management in Pawarenga This thesis is a study of how tikanga Māori principles could be used in practice in the management of natural hazards and in particular flooding in a rural area, Pawarenga. The aim was to investigate and document Te Uri O Tai Hapū preferred strategies for reducing flood risk in Pawarenga and to consider opportunities to use tikanga Māori principles and values in emergency response. The identification of key concepts and principles of tikanga Māori customs and their connections to whānau and hapū of Te Uri O Tai is key to this study. I used kaupapa Māori research methodologies as a guiding framework since researching in my own community required me to manage accountability both to its members and to the university. In particular it was important to obtain permission from the community before beginning, to ensure my research processes were acceptable, and to return my findings to the community. Qualitative data was gathered from a series of hui and interviews with local community members. Data was analysed inductively and organised into thematic networks. Two major organising themes were identified: resilience and vulnerability. Participants described a broad range of strengths inherent in the community that enabled them to respond to crises such as flood events. A number of cultural, social, physical, economic and political vulnerabilities were also identified; most of these were fundamental aspects of people‘s daily lives and did not prevent them from responding positively when floods occurred, but may have limited the scope of their responses. Tikanga was not a subject that participants felt comfortable talking about, but from the descriptions of how people actually responded during floods I was able to see examples of how tikanga was used. The resilience of the Pawarenga community is taken for granted by residents. When disasters such as floods occur, their resiliencies and strengths are brought into play to ensure the safety of all in the community. Tikanga Māori is an inherent part of this resiliency, and marae structures and protocols already in place provide a vital framework for flood response. I conclude that tikanga already has enormous value in flood response, and for Māori communities is an obvious choice as a foundation for a flood emergency management strategy. Furthermore, the value of tikanga as a flood emergency management strategy should be more explicitly recognised and supported by all authorities involved in disaster response and management. It was also clear that multiple dimensions of vulnerability (physical, cultural, social, economic and political) affect the Pawarenga community, and to some extent limit their capacity to respond. In particular political processes that exclude them from participating in decision-making and planning around environmental management generally have left people feeling marginalised, since they are unable to fulfil their kaitiaki role. With civil defence emergency management policies explicitly focused around resilience, participation of Te Uri O Tai Hapū in planning for emergency management should allow for their existing resilience, which stems from the upholding of tikanga, to be recognised and strengthened. However, this will only happen if relationships with the various authorities involved in emergency and natural hazard response are fostered, full participation in decision-making and in responding to natural hazard events is facilitated, and resources are available to support the community with their endeavours.

year: 2010