title: Observations of shoreline–sandbar coupling on an embayed beach

authors: van de Lageweg, W.I.

subjects: shoreline

abstract: We analyse a seven-year dataset (1999–2005) of shoreline and sandbar variations derived from video observations at the embayed Tairua Beach, New Zealand, to explore sandbar–shoreline coupling and to determine how this coupling is related to alongshore-averaged sandbar–shoreline separation and beach rotation. Our results quantify the coupling between the sandbar and the shoreline which is directly related to the reduced separation between the sandbar and the shoreline. Using a simple predictive shoreline model, we show that this behaviour is related to the energy of the incoming waves. Our observations are obtained from a headland-enclosed beach and show aspects of the morphological state that relate to the existence of headlands that are not considered in the Wright and Short beach state classification. Both the sandbar and shoreline at Tairua Beach rotate relatively quickly (< 1 month) during the winter storm events, when the storms are accompanied by strong alongshore components, gradually returning during the summer months. The sandbar–shoreline coupling length scale is controlled by this rotation, with large wavelengths occurring when the sandbar is strongly rotated.

text: Observations of shoreline–sandbar coupling on an embayed beach We analyse a seven-year dataset (1999–2005) of shoreline and sandbar variations derived from video observations at the embayed Tairua Beach, New Zealand, to explore sandbar–shoreline coupling and to determine how this coupling is related to alongshore-averaged sandbar–shoreline separation and beach rotation. Our results quantify the coupling between the sandbar and the shoreline which is directly related to the reduced separation between the sandbar and the shoreline. Using a simple predictive shoreline model, we show that this behaviour is related to the energy of the incoming waves. Our observations are obtained from a headland-enclosed beach and show aspects of the morphological state that relate to the existence of headlands that are not considered in the Wright and Short beach state classification. Both the sandbar and shoreline at Tairua Beach rotate relatively quickly (< 1 month) during the winter storm events, when the storms are accompanied by strong alongshore components, gradually returning during the summer months. The sandbar–shoreline coupling length scale is controlled by this rotation, with large wavelengths occurring when the sandbar is strongly rotated.

year: 2013

title: Improving the Quality of Real Time Media Applications through Sending the Best Packet Next

authors: McDonald, Ian

abstract: Real time media applications such as video conferencing are increasing in usage. These bandwidth intensive applications put high demands on a network and often the quality experienced by the user is sub-optimal.

In a traditional network stack, data from an application is transmitted in the order that it is received. This thesis proposes a scheme called "Send the Best Packet Next (SBPN)" where the most important data is transmitted first and data that will not reach the receiver before an expiry time is not transmitted. In SBPN the packet priority and expiry time are added to a packet and used in conjunction with the Round Trip Time (RTT) to determine whether packets are sent, and in which order that they are sent. For example, it has been shown that audio is more important to users than video in video conferencing. SBPN could be considered to be Quality of Service (QoS) that is within an application data stream. This is in comparison to network routers that provide QoS to whole streams such as Voice over IP (VoIP), but do not differentiate between data items within the stream or which data gets transmitted by the end nodes. Implementation of SBPN can be done on the server only, so that much of the benefit for one way transmission (e.g. live television) can be gained without requiring existing clients to be changed.

SBPN was implemented in a Linux kernel on top of Datagram Congestion Control Protocol (DCCP) and compared to existing solutions. This showed real improvement in the measured quality of audio with a maximum improvement of 15% in selected test scenarios.

text: Improving the Quality of Real Time Media Applications through Sending the Best Packet Next Real time media applications such as video conferencing are increasing in usage. These bandwidth intensive applications put high demands on a network and often the quality experienced by the user is sub-optimal.

In a traditional network stack, data from an application is transmitted in the order that it is received. This thesis proposes a scheme called "Send the Best Packet Next (SBPN)" where the most important data is transmitted first and data that will not reach the receiver before an expiry time is not transmitted. In SBPN the packet priority and expiry time are added to a packet and used in conjunction with the Round Trip Time (RTT) to determine whether packets are sent, and in which order that they are sent. For example, it has been shown that audio is more important to users than video in video conferencing. SBPN could be considered to be Quality of Service (QoS) that is within an application data stream. This is in comparison to network routers that provide QoS to whole streams such as Voice over IP (VoIP), but do not differentiate between data items within the stream or which data gets transmitted by the end nodes. Implementation of SBPN can be done on the server only, so that much of the benefit for one way transmission (e.g. live television) can be gained without requiring existing clients to be changed.

SBPN was implemented in a Linux kernel on top of Datagram Congestion Control Protocol (DCCP) and compared to existing solutions. This showed real improvement in the measured quality of audio with a maximum improvement of 15% in selected test scenarios.

year: 2013

title: Lost in translation: western representations of Māori knowledge

authors: Mika, Carl Te Hira

abstract: We recently attended a conference at which a non-Māori presenter, drawing on a particular metaphor already established by Māori writers, related Māori natural world features to a research method. The presentation was useful because it highlighted several issues that call for our concern as Māori philosophers. In this article, we outline these concerns, which are: first, that a blunt response to such a presentation is not undertaken lightly from a Māori viewpoint; and, second, that the presenter’s talk exemplifies a wider problem of warping Māori concepts and labels to fit a Western philosophical approach. We call this latter problem ‘Translation’, because it involves moving the Māori world and its phenomena over into one that is palatable for policy and research. The aim of the article is not to single out the presenter, but rather to refer to his presentation in order to consider the prior issue of Translation. In cases where Translation occurs, a Māori critical philosophical stance is clearly needed, in order to both investigate the warping of Māori thought on which it relies, and review the place of Māori philosophy and philosophical response in the arena of educational research.

text: Lost in translation: western representations of Māori knowledge We recently attended a conference at which a non-Māori presenter, drawing on a particular metaphor already established by Māori writers, related Māori natural world features to a research method. The presentation was useful because it highlighted several issues that call for our concern as Māori philosophers. In this article, we outline these concerns, which are: first, that a blunt response to such a presentation is not undertaken lightly from a Māori viewpoint; and, second, that the presenter’s talk exemplifies a wider problem of warping Māori concepts and labels to fit a Western philosophical approach. We call this latter problem ‘Translation’, because it involves moving the Māori world and its phenomena over into one that is palatable for policy and research. The aim of the article is not to single out the presenter, but rather to refer to his presentation in order to consider the prior issue of Translation. In cases where Translation occurs, a Māori critical philosophical stance is clearly needed, in order to both investigate the warping of Māori thought on which it relies, and review the place of Māori philosophy and philosophical response in the arena of educational research.

year: 2017