title: Design and evaluation of an optimistic CPU: the warp engine

authors: Littin, Richard H.

abstract: Instruction pipelining, out-of-order execution, and branch prediction are techniques that improve performance in processors by manipulating the flow of instructions. These control flow manipulations alone are not adequate to allow large numbers of instructions to execute in parallel because performance is limited by accesses to the relatively slow memory system. Performance can be improved by speculating on the outcomes of control decisions, and the values of data in memory, returning results early. This thesis investigates the requirements of an architecture that speculates on control flow decisions and data values to improve performance through instruction level parallelism.

A new architecture, the WarpEngine, that speculates on control flow decisions and data values is presented. This architecture is shown to have the potential to extract performance through parallelism an order of magnitude larger than that obtained by contemporary microprocessors. Control speculation is achieved using a novel tree-based mechanism that produces multiple flows of control. This scalable mechanism is shown to generate a large group of instructions that can execute in parallel. Also, it is essential that memory accesses are allowed to occur out of programmed order. This form of data speculation is shown to break false data dependencies, improving performance. The use of state saving resources is examined and the limitations of in-order retirement schemes are shown. These results indicate that the management of these resources is critical to obtaining good performance.

Virtual ordered simulation is introduced as a new simulation methodology for modelling out-of-order and speculative architectures. This novel simulation technique is unique because each instruction is only inspected and processed once, and unlike other simulation methodologies unlimited resources can be modelled. Individual components can be constrained in isolation so that their effect on performance can be examined in detail. Investigations performed assuming unbounded resources provide new insight into the limits imposed by individual processor components.

The architecture presented shows potential for performance well beyond that of contemporary and research architectures. The insights into the limitations of processor components apply to many computer architectures.

text: Design and evaluation of an optimistic CPU: the warp engine Instruction pipelining, out-of-order execution, and branch prediction are techniques that improve performance in processors by manipulating the flow of instructions. These control flow manipulations alone are not adequate to allow large numbers of instructions to execute in parallel because performance is limited by accesses to the relatively slow memory system. Performance can be improved by speculating on the outcomes of control decisions, and the values of data in memory, returning results early. This thesis investigates the requirements of an architecture that speculates on control flow decisions and data values to improve performance through instruction level parallelism.

A new architecture, the WarpEngine, that speculates on control flow decisions and data values is presented. This architecture is shown to have the potential to extract performance through parallelism an order of magnitude larger than that obtained by contemporary microprocessors. Control speculation is achieved using a novel tree-based mechanism that produces multiple flows of control. This scalable mechanism is shown to generate a large group of instructions that can execute in parallel. Also, it is essential that memory accesses are allowed to occur out of programmed order. This form of data speculation is shown to break false data dependencies, improving performance. The use of state saving resources is examined and the limitations of in-order retirement schemes are shown. These results indicate that the management of these resources is critical to obtaining good performance.

Virtual ordered simulation is introduced as a new simulation methodology for modelling out-of-order and speculative architectures. This novel simulation technique is unique because each instruction is only inspected and processed once, and unlike other simulation methodologies unlimited resources can be modelled. Individual components can be constrained in isolation so that their effect on performance can be examined in detail. Investigations performed assuming unbounded resources provide new insight into the limits imposed by individual processor components.

The architecture presented shows potential for performance well beyond that of contemporary and research architectures. The insights into the limitations of processor components apply to many computer architectures.

year: 2000

title: Translation and validation of the Arabic version of the Digital Stress Scale (DSS-A) with three Arabic-speaking samples

authors: Krägeloh, Christian U.

abstract: Objective: Given the ubiquitous nature of digital technologies such as smartphones, research has increasingly focused on the health outcomes of prolonged use of such technologies. The Digital Stress Scale (DSS) has been developed recently, but it is currently only available in English and Chinese, and validations in other languages are warranted. 
Methods: The 24-item DSS was translated into Arabic using the method of translation and back-translation. Using a general population sample (n = 1069) from Saudi Arabia, Oman, and Jordan, the psychometric properties of the Arabic DSS (DSS-A) were investigated using higher-order confirmatory factor analysis.
Results: The original five-factor structure was replicated for the DSS-A without the need for any modifications such as item deletion or reassignment of items to another factor. Reliability was excellent for the total scale score (α = 0.92) as well as for the five subscales (α ranged between 0.81 and 0.91). Convergent validity was supported by significant correlations between the DSS-A and psychological distress. 
Conclusion: The strong psychometric properties of the DSS-A imply that this scale can now be used with high validity and reliability to explore the role of digital stress and its sub-characteristics in Arabic-speaking populations.

text: Translation and validation of the Arabic version of the Digital Stress Scale (DSS-A) with three Arabic-speaking samples Objective: Given the ubiquitous nature of digital technologies such as smartphones, research has increasingly focused on the health outcomes of prolonged use of such technologies. The Digital Stress Scale (DSS) has been developed recently, but it is currently only available in English and Chinese, and validations in other languages are warranted. 
Methods: The 24-item DSS was translated into Arabic using the method of translation and back-translation. Using a general population sample (n = 1069) from Saudi Arabia, Oman, and Jordan, the psychometric properties of the Arabic DSS (DSS-A) were investigated using higher-order confirmatory factor analysis.
Results: The original five-factor structure was replicated for the DSS-A without the need for any modifications such as item deletion or reassignment of items to another factor. Reliability was excellent for the total scale score (α = 0.92) as well as for the five subscales (α ranged between 0.81 and 0.91). Convergent validity was supported by significant correlations between the DSS-A and psychological distress. 
Conclusion: The strong psychometric properties of the DSS-A imply that this scale can now be used with high validity and reliability to explore the role of digital stress and its sub-characteristics in Arabic-speaking populations.

year: 2023-12-01

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