title: A Magnitude Effect in Temporal discounting with Hens

authors: Budenberg, Grace Joy

subjects: Magnitude effect

abstract: This study aimed to determine whether a magnitude effect could be obtained in temporal discounting with brown shaver hens. Subjects responded in a classic self-control situation for the choice between a smaller-sooner reward (1-s access to food, after a 2 s delay) or a larger-later reward (4.5-s access to food, after a 28 s delay). Hens responded in a multiple concurrent-chain procedure on concurrent variable-interval (VI-30s, VI 30-s) schedules in the choice phase (initial links), and a fixed interval (FI) schedule, ranging from FI 2-s to FI 28-s in the outcome phase (terminal links). The outcome phase then resulted in reinforcement of either 1-s access to grain or 4.5-s access to grain. The results replicated the findings of a previous study by Grace, Sargisson & White (2012), who obtained evidence of a magnitude effect in temporal discounting with pigeons, in which subjects demonstrated a greater preference for the larger reward compared to the small reward over increasing time delay. The findings indicate that the magnitude effect is not unique to humans, as previous studies have suggested. Data was applied the Generalized Matching Law (GML) and the Contextual Choice Model (CCM) equations to determine if the data was comparable with models of behavioural choice.

text: A Magnitude Effect in Temporal discounting with Hens This study aimed to determine whether a magnitude effect could be obtained in temporal discounting with brown shaver hens. Subjects responded in a classic self-control situation for the choice between a smaller-sooner reward (1-s access to food, after a 2 s delay) or a larger-later reward (4.5-s access to food, after a 28 s delay). Hens responded in a multiple concurrent-chain procedure on concurrent variable-interval (VI-30s, VI 30-s) schedules in the choice phase (initial links), and a fixed interval (FI) schedule, ranging from FI 2-s to FI 28-s in the outcome phase (terminal links). The outcome phase then resulted in reinforcement of either 1-s access to grain or 4.5-s access to grain. The results replicated the findings of a previous study by Grace, Sargisson & White (2012), who obtained evidence of a magnitude effect in temporal discounting with pigeons, in which subjects demonstrated a greater preference for the larger reward compared to the small reward over increasing time delay. The findings indicate that the magnitude effect is not unique to humans, as previous studies have suggested. Data was applied the Generalized Matching Law (GML) and the Contextual Choice Model (CCM) equations to determine if the data was comparable with models of behavioural choice.

year: 2014

title: Estimation of photovoltaic conversion efficiency of a building integrated photovoltaic/thermal (BIPV/T) collector array using an artificial neural network

authors: Ghani, Faisal Abid

subjects: artificial neural network

abstract: Earlier studies have shown that the thermal efficiency of a solar thermal collector is influenced by the quality of coolant flow distribution within the array. The quality of flow distribution within a header/riser type fluid network is influenced by a number of parameters including the coolant mass flow rate, the direction of flow in the manifolds, and most importantly the geometry of the array. As a building integrated photovoltaic thermal (BIPVT) collector will be a made to measure product, meaning its dimensions will be dictated by the specific roofing and energy requirements of the customer, the issue of flow distribution and its effect on both thermal and photovoltaic performance raises some concern. In order to quantify the detrimental effect flow distribution may have on the photovoltaic output of a BIPVT array, a numerical approach was presented by authors in earlier work where factors known to influence flow distribution were varied. The authors demonstrated that photovoltaic output may be severely hindered if the issue of flow distribution is not adequately addressed. In this new study we use this numerical method to additionally show that photovoltaic output is not always improved by reducing the fin width W (by increasing the number of risers for each module) despite the theoretical rise in fin efficiency F as a consequence of flow distribution. Under certain scenarios it was shown that a single riser will in fact improve PV output and also reduce system installation cost and complexity. The combination of these new finding and results previously obtained by the authors highlights the need in selecting the optimal design parameters to meet the specific requirements of each installation. The numerical approach carried out to calculate PV output however was time consuming and computationally intensive and therefore not feasible to perform for each and every customer. To address this issue, the authors have proposed in this paper to train an artificial neural network which can be used to approximate the photovoltaic yield of an array of specified shape operating under parallel{minus 45 degree rule}reverse flow in the manifolds and also with one or two fluid channels cooling each string of cells. By approximating the yield for each scenario, the optimal configuration can then be chosen. It was found that the neural network can be successfully trained for this specific application offering a fast alternative to the original numerical approach.

text: Estimation of photovoltaic conversion efficiency of a building integrated photovoltaic/thermal (BIPV/T) collector array using an artificial neural network Earlier studies have shown that the thermal efficiency of a solar thermal collector is influenced by the quality of coolant flow distribution within the array. The quality of flow distribution within a header/riser type fluid network is influenced by a number of parameters including the coolant mass flow rate, the direction of flow in the manifolds, and most importantly the geometry of the array. As a building integrated photovoltaic thermal (BIPVT) collector will be a made to measure product, meaning its dimensions will be dictated by the specific roofing and energy requirements of the customer, the issue of flow distribution and its effect on both thermal and photovoltaic performance raises some concern. In order to quantify the detrimental effect flow distribution may have on the photovoltaic output of a BIPVT array, a numerical approach was presented by authors in earlier work where factors known to influence flow distribution were varied. The authors demonstrated that photovoltaic output may be severely hindered if the issue of flow distribution is not adequately addressed. In this new study we use this numerical method to additionally show that photovoltaic output is not always improved by reducing the fin width W (by increasing the number of risers for each module) despite the theoretical rise in fin efficiency F as a consequence of flow distribution. Under certain scenarios it was shown that a single riser will in fact improve PV output and also reduce system installation cost and complexity. The combination of these new finding and results previously obtained by the authors highlights the need in selecting the optimal design parameters to meet the specific requirements of each installation. The numerical approach carried out to calculate PV output however was time consuming and computationally intensive and therefore not feasible to perform for each and every customer. To address this issue, the authors have proposed in this paper to train an artificial neural network which can be used to approximate the photovoltaic yield of an array of specified shape operating under parallel{minus 45 degree rule}reverse flow in the manifolds and also with one or two fluid channels cooling each string of cells. By approximating the yield for each scenario, the optimal configuration can then be chosen. It was found that the neural network can be successfully trained for this specific application offering a fast alternative to the original numerical approach.

year: 2012

title: Different coloured tears: Dual cultural identity and Tangihanga

authors: Edge, Kiri

subjects: bereavement

abstract: Although whānau/family that are configured by both Pākehā and Māori identities number significantly within New Zealand, there has been little or no attention paid to the ways in which these identities influence the bereavement processes that will inevitably impact upon the lives of these whānau/family. The present study explored the experiences of an individual, whose whānau/family included two life ways: Māori and Pākehā. Of specific focus was the ways in which these identities influenced his bereavement subsequent to the death of his beloved wife, who was of Māori descent. One elderly male Pākehā participant was interviewed, using an open ended narrative approach. The interview was semi-structured around five broad themes, but the focus was upon the participant’s experiences and his preference in expressing these. The data analysis utilised a thematic process which allowed the participant’s experiences to determine the emergent themes. The results depicted the diversity of issues that may be raised for dual cultural whānau/family within bereavement processes. Two central themes are discussed in relation to intercultural conflict and the eventual resolution that was created. Decision-making processes, cultural and language differences played significant roles within the conflict and exclusion experienced by the participant. Communication and compromise provided resolution to the prior conflicts experienced. This created positive and unexpected outcomes which resulted in increased understandings and the strengthening of links between the participant, his whānau/family and his wife’s marae.

text: Different coloured tears: Dual cultural identity and Tangihanga Although whānau/family that are configured by both Pākehā and Māori identities number significantly within New Zealand, there has been little or no attention paid to the ways in which these identities influence the bereavement processes that will inevitably impact upon the lives of these whānau/family. The present study explored the experiences of an individual, whose whānau/family included two life ways: Māori and Pākehā. Of specific focus was the ways in which these identities influenced his bereavement subsequent to the death of his beloved wife, who was of Māori descent. One elderly male Pākehā participant was interviewed, using an open ended narrative approach. The interview was semi-structured around five broad themes, but the focus was upon the participant’s experiences and his preference in expressing these. The data analysis utilised a thematic process which allowed the participant’s experiences to determine the emergent themes. The results depicted the diversity of issues that may be raised for dual cultural whānau/family within bereavement processes. Two central themes are discussed in relation to intercultural conflict and the eventual resolution that was created. Decision-making processes, cultural and language differences played significant roles within the conflict and exclusion experienced by the participant. Communication and compromise provided resolution to the prior conflicts experienced. This created positive and unexpected outcomes which resulted in increased understandings and the strengthening of links between the participant, his whānau/family and his wife’s marae.

year: 2011