title: The telegraph equation for cosmic-ray transport with weak adiabatic focusing

authors: Litvinenko, Yuri E.

subjects: particle emission

abstract: Time-dependent solutions of a spatial diffusion equation are often used to describe the transport of solar energetic particles, accelerated in large solar flares. Approximate analytical solutions of the diffusion approximation can complement and guide detailed numerical solutions of the Fokker-Planck equation for the particle distribution function. The accuracy of the diffusion approximation is limited, however, because the signal propagation speed is infinite in the diffusion limit. An improved description of cosmic-ray transport is provided by the telegraph equation, characterised by a finite signal propagation speed. We derive the telegraph equation for the particle density, taking into account adiabatic focusing in a large-scale interplanetary magnetic field in a weak focusing limit. As an illustration, we calculate a propagating pulse solution of the telegraph equation, determine the rise time when the maximum particle intensity is reached at a given distance from the Sun, and compare the results with those obtained in the diffusion approximation. In comparison with the diffusion equation, the telegraph equation predicts an asymmetrical shape of the pulse and a shorter rise time. These potentially significant differences suggest that the more accurate telegraph equation should be used in analysis of the solar energetic particle data, at least to quantify the accuracy of the focused diffusion model.

text: The telegraph equation for cosmic-ray transport with weak adiabatic focusing Time-dependent solutions of a spatial diffusion equation are often used to describe the transport of solar energetic particles, accelerated in large solar flares. Approximate analytical solutions of the diffusion approximation can complement and guide detailed numerical solutions of the Fokker-Planck equation for the particle distribution function. The accuracy of the diffusion approximation is limited, however, because the signal propagation speed is infinite in the diffusion limit. An improved description of cosmic-ray transport is provided by the telegraph equation, characterised by a finite signal propagation speed. We derive the telegraph equation for the particle density, taking into account adiabatic focusing in a large-scale interplanetary magnetic field in a weak focusing limit. As an illustration, we calculate a propagating pulse solution of the telegraph equation, determine the rise time when the maximum particle intensity is reached at a given distance from the Sun, and compare the results with those obtained in the diffusion approximation. In comparison with the diffusion equation, the telegraph equation predicts an asymmetrical shape of the pulse and a shorter rise time. These potentially significant differences suggest that the more accurate telegraph equation should be used in analysis of the solar energetic particle data, at least to quantify the accuracy of the focused diffusion model.

year: 2013

title: High precision traffic measurement by the WAND research group

authors: Cleary, John G.

subjects: computer science

abstract: Over recent years the size and capacity of the Internet has continued its exponential growth driven by new applications and improving network technology. These changes are particularly significant in the New Zealand context where the high costs of trans-Pacific traffic has mandated that traffic be charged for by volume. This has also lead to a significant focus within the New Zealand Internet community on issues of caching and of careful planning for capacity. 
Approximately three years ago the WAND research group began with a program to measure ATM traffic. We were sharply constrained by cost and decided to start by reprogramming some ATM NIC cards. This paper is largely based on our experience as we have broadened this work to include IP-based non-ATM networks and the construction of our own hardware. We have learned a number of lessons in this work, rediscovering along the way some of the hard discipline that all observation scientists must submit to.

text: High precision traffic measurement by the WAND research group Over recent years the size and capacity of the Internet has continued its exponential growth driven by new applications and improving network technology. These changes are particularly significant in the New Zealand context where the high costs of trans-Pacific traffic has mandated that traffic be charged for by volume. This has also lead to a significant focus within the New Zealand Internet community on issues of caching and of careful planning for capacity. 
Approximately three years ago the WAND research group began with a program to measure ATM traffic. We were sharply constrained by cost and decided to start by reprogramming some ATM NIC cards. This paper is largely based on our experience as we have broadened this work to include IP-based non-ATM networks and the construction of our own hardware. We have learned a number of lessons in this work, rediscovering along the way some of the hard discipline that all observation scientists must submit to.

year: 1999-12

title: He tangi mai i te puehu: He whakatewhatewha i te mahi whakamāori me te reo ā-tuhi a ngā tūpuna

authors: Apiata, Hāwea

subjects: Māori spirituality

abstract: Kei te pūtahi o tēnei tuhinga whakapae ko te whakatewhatewha i te whakapapa o te whakaaro Māori (Māori intellectual history) mā ēnei pātai e rua: He aha ā te Māori i tuhituhi ai i te tōmuatanga o te rautau rua tekau? Ā, he pēhea tāna wetewete i ngā huatau whakawairua nō waho i te ao Māori? 

Ina koa, ko tā te tuhinga whakapae nei he whakaaranga, he whakaatu hoki i ētahi huarahi e toru hei rangahau i ngā whakapapa o te whakaaro taketake: ko te ketuketu rua mahara (archival research); ko te tātari ariā (conceptual analysis); me te reo e whakamahia ana kia wetewete i te kaupapa. Mā te mahi ketuketu rua mahara e āhei ai ki te wānanga i ngā whakaputanga a Wiremu Takana, he kaituhi, he kaiwhakamāori nō Ngāti Kahungunu. Ka whakaputaina tāna tuhinga tuatahi i te tau 1915. Ā, e rua anō i whakaputaina e ia i te tau whai muri mai i 1916. Ko ēnei tuhinga āna e whakatewhatewha ana i te whakamāoritanga o te rongopai me te āheinga o ngā pūrākau Māori kia whakamārama i ngā whakaakoranga Moromona. Kāore anō kia āta tātaritia, kia āta rangahaua āna pukapuka e tētahi atu o mua. Ko te huarahi rangahau tuarua ko te tātari i te whakamāoritanga o ētahi ariā whakawairua e kitea ana i roto i ngā karaipiture o te Hāhi o Ihu Karaiti o te Hunga Tapu o ngā Rā o Muri nei. E toru ngā ariā kua tīpakongia hei tirotiro, arā, ko heaven, hell me baptism. Ā, hei whakawhānui atu i te titiro ki tēnei kaupapa, ka huritaongia ngā hua o te tuhinga reo Māori, arā, ka matapakina ngā take kia tuhituhi i te mahi rangahau i roto i te reo Māori.

I te mutunga iho, mā te āta wānanga i ngā whakaputanga reo Māori a te Hāhi o Ihu Karaiti (LDS) e whakawhānuitia ai tō tātou māramatanga ki te hītori o te mahi whakaputa pukapuka i roto i te Hāhi, te mahi punenga a te Māori, te whakareretanga o ngā tuhituhinga reo Māori, me te hītori o te Hāhi o Ihu Karaiti i Aotearoa nei.

text: He tangi mai i te puehu: He whakatewhatewha i te mahi whakamāori me te reo ā-tuhi a ngā tūpuna Kei te pūtahi o tēnei tuhinga whakapae ko te whakatewhatewha i te whakapapa o te whakaaro Māori (Māori intellectual history) mā ēnei pātai e rua: He aha ā te Māori i tuhituhi ai i te tōmuatanga o te rautau rua tekau? Ā, he pēhea tāna wetewete i ngā huatau whakawairua nō waho i te ao Māori? 

Ina koa, ko tā te tuhinga whakapae nei he whakaaranga, he whakaatu hoki i ētahi huarahi e toru hei rangahau i ngā whakapapa o te whakaaro taketake: ko te ketuketu rua mahara (archival research); ko te tātari ariā (conceptual analysis); me te reo e whakamahia ana kia wetewete i te kaupapa. Mā te mahi ketuketu rua mahara e āhei ai ki te wānanga i ngā whakaputanga a Wiremu Takana, he kaituhi, he kaiwhakamāori nō Ngāti Kahungunu. Ka whakaputaina tāna tuhinga tuatahi i te tau 1915. Ā, e rua anō i whakaputaina e ia i te tau whai muri mai i 1916. Ko ēnei tuhinga āna e whakatewhatewha ana i te whakamāoritanga o te rongopai me te āheinga o ngā pūrākau Māori kia whakamārama i ngā whakaakoranga Moromona. Kāore anō kia āta tātaritia, kia āta rangahaua āna pukapuka e tētahi atu o mua. Ko te huarahi rangahau tuarua ko te tātari i te whakamāoritanga o ētahi ariā whakawairua e kitea ana i roto i ngā karaipiture o te Hāhi o Ihu Karaiti o te Hunga Tapu o ngā Rā o Muri nei. E toru ngā ariā kua tīpakongia hei tirotiro, arā, ko heaven, hell me baptism. Ā, hei whakawhānui atu i te titiro ki tēnei kaupapa, ka huritaongia ngā hua o te tuhinga reo Māori, arā, ka matapakina ngā take kia tuhituhi i te mahi rangahau i roto i te reo Māori.

I te mutunga iho, mā te āta wānanga i ngā whakaputanga reo Māori a te Hāhi o Ihu Karaiti (LDS) e whakawhānuitia ai tō tātou māramatanga ki te hītori o te mahi whakaputa pukapuka i roto i te Hāhi, te mahi punenga a te Māori, te whakareretanga o ngā tuhituhinga reo Māori, me te hītori o te Hāhi o Ihu Karaiti i Aotearoa nei.

year: 2021