title: Hidden Terminal Detection in Wide-Area 802.11 Wireless Networks

authors: Raynel, Scott McKenzie

subjects: hidden terminals

abstract: The hidden terminal problem is an important issue in wireless networks based on the CSMA medium access control scheme. Hidden terminals pose a complex challenge to network operators trying to identify the underlying cause of performance issues.
This thesis describes new methods for the detection and measurement of the hidden terminal problem in wireless networks based on commodity hardware and software platforms. These new methods allow network operators to identify areas of a network where hidden terminals are likely to exist; detect instances of the hidden terminal problem occurring; and estimate the total impact hidden terminals are having on the performance of the network.
A new framework for measurement of wireless networks is described which provides a new approach to wireless measurement on Linux based wireless routers. The new framework is used to implement the methods and they are deployed across an operational commercial wireless network and are shown to be useful.

text: Hidden Terminal Detection in Wide-Area 802.11 Wireless Networks The hidden terminal problem is an important issue in wireless networks based on the CSMA medium access control scheme. Hidden terminals pose a complex challenge to network operators trying to identify the underlying cause of performance issues.
This thesis describes new methods for the detection and measurement of the hidden terminal problem in wireless networks based on commodity hardware and software platforms. These new methods allow network operators to identify areas of a network where hidden terminals are likely to exist; detect instances of the hidden terminal problem occurring; and estimate the total impact hidden terminals are having on the performance of the network.
A new framework for measurement of wireless networks is described which provides a new approach to wireless measurement on Linux based wireless routers. The new framework is used to implement the methods and they are deployed across an operational commercial wireless network and are shown to be useful.

year: 2012

title: Identification of central mechanisms underlying statin-induced changes in consummatory behaviour in rats

authors: Isgrove, Kiriana

subjects: simvastatin

abstract: Simvastatin is a cholesterol lowering statin whose adverse effects include an increase in appetite and, consequently, obesity. This is counterproductive to the otherwise beneficial outcomes of simvastatin on metabolic and cardiovascular health. The mechanisms underlying simvastatin-induced hyperphagia are unknown. This thesis investigated by using a laboratory rat model whether central mechanisms contribute to simvastatin-induced increase in appetite. First, the effect of intracerebroventricularly (ICV) administered simvastatin on the energy-driven intake of ‘bland’ chow, and on reward-motivated consumption of palatable solutions, was determined. The data indicate that ICV simvastatin moderately increases ingestion of energy-dense chow, but it does not affect consumption of calorie-dilute and non-caloric palatable sucrose or saccharin solutions. It suggests that simvastatin acting directly at the brain level elevates intake of energy, while being ineffective in stimulating eating for reward. Surprisingly, rats injected ICV with this statin consume also significantly more water after water deprivation, which points to a relationship between centrally acting simvastatin and thirst-related processing. In the second part of this project, the effect of the orexigenic dose of ICV simvastatin on neuronal activation in consumption-related hypothalamic sites was investigated. Simvastatin elevated c-Fos immunoreactivity, which serves as a marker of neuronal activation, in the arcuate and paraventricular nuclei, two sites that have a profound influence on the regulation of energy intake and energy balance, as well as affect water balance. It can be concluded that simvastatin increases intake of energy and of water, and that it likely exerts its action through the hypothalamic paraventricular and arcuate nuclei.

text: Identification of central mechanisms underlying statin-induced changes in consummatory behaviour in rats Simvastatin is a cholesterol lowering statin whose adverse effects include an increase in appetite and, consequently, obesity. This is counterproductive to the otherwise beneficial outcomes of simvastatin on metabolic and cardiovascular health. The mechanisms underlying simvastatin-induced hyperphagia are unknown. This thesis investigated by using a laboratory rat model whether central mechanisms contribute to simvastatin-induced increase in appetite. First, the effect of intracerebroventricularly (ICV) administered simvastatin on the energy-driven intake of ‘bland’ chow, and on reward-motivated consumption of palatable solutions, was determined. The data indicate that ICV simvastatin moderately increases ingestion of energy-dense chow, but it does not affect consumption of calorie-dilute and non-caloric palatable sucrose or saccharin solutions. It suggests that simvastatin acting directly at the brain level elevates intake of energy, while being ineffective in stimulating eating for reward. Surprisingly, rats injected ICV with this statin consume also significantly more water after water deprivation, which points to a relationship between centrally acting simvastatin and thirst-related processing. In the second part of this project, the effect of the orexigenic dose of ICV simvastatin on neuronal activation in consumption-related hypothalamic sites was investigated. Simvastatin elevated c-Fos immunoreactivity, which serves as a marker of neuronal activation, in the arcuate and paraventricular nuclei, two sites that have a profound influence on the regulation of energy intake and energy balance, as well as affect water balance. It can be concluded that simvastatin increases intake of energy and of water, and that it likely exerts its action through the hypothalamic paraventricular and arcuate nuclei.

year: 2017

title: The art of dialogue with indigenous communities in the new biotechnology world

authors: Hudson, Maui

subjects: biotechnology

abstract: Te Hau Mihi Ata is a research project that aims to negotiate spaces for and develop processes of dialogue that allow for a deeper level of interaction between mtauranga Māori (Māori indigenous knowledge) and science. Over a two-year period a series of facilitated exchanges or wnanga were held focusing on areas of new technology (assisted reproductive technologies, life technologies, and future food technologies) that involved Māori scientists and people with expertise in mtauranga Māori. These dialogue events were designed to explore, through the challenge of considering new biotechnologies, the similarities and differences that emerge from approaching these issues from different knowledge paradigms. This paper will outline the key project findings from this series of exchanges including the barriers and facilitators to the dialogue process and knowledge exchange as well as discuss how participants created connections between scientific discourse and indigenous knowledge frameworks.

text: The art of dialogue with indigenous communities in the new biotechnology world Te Hau Mihi Ata is a research project that aims to negotiate spaces for and develop processes of dialogue that allow for a deeper level of interaction between mtauranga Māori (Māori indigenous knowledge) and science. Over a two-year period a series of facilitated exchanges or wnanga were held focusing on areas of new technology (assisted reproductive technologies, life technologies, and future food technologies) that involved Māori scientists and people with expertise in mtauranga Māori. These dialogue events were designed to explore, through the challenge of considering new biotechnologies, the similarities and differences that emerge from approaching these issues from different knowledge paradigms. This paper will outline the key project findings from this series of exchanges including the barriers and facilitators to the dialogue process and knowledge exchange as well as discuss how participants created connections between scientific discourse and indigenous knowledge frameworks.

year: 2012