title: Linear Genetic Programming with Experience

authors: Liu, Liang

subjects: Linear Genetic Programming

abstract: A novel method of using Machine Learning (ML) algorithms to improve the performance of Linear Genetic Programming (LGP) is studied. In this study, structures used to organize the trained ML models are called Experience Models (EM). They are used for different mutate actions of the mutation operator in LGP. The purpose of using EM is to regulate the random search performed by the mutation operator. The aim of using EMs is to let the suitable candidates have higher chances to be selected.
In this study, two sources of knowledge are used to create the training sets that are used to train ML models. The first source is the pre-existing knowledge of symbolic regression. This knowledge reflects the effect of adding one math function segment to another math function segment. The second source is the knowledge generated during the evolution of LGP. This knowledge reflects the effect of using different gene components at different chromosome indexes on the overall fitness. Based on these two sources of knowledge, two types of EM are designed. They are Static Model (SM) and Dynamic Model (DM). The SM uses ML models trained with the first knowledge source. A SM tries to achieve the aim of using an EM by reducing the size of the candidate sets used by the increase action of the mutation operator. The DM uses ML models trained with the second knowledge source. A DM tries to achieve the aim of using an EM by creating distributions of gene component types, which can reflect the information in the second knowledge source, for change action of the mutation operator. In this study, SM is used only for increase action in the mutation operator; DM is used only for change action in the mutation operator.
From the experiment results, if compared with a LGP, when a LGP using a SM, it tends to need fewer generations to have a hit, at the same time achieving similar mean best fitness. In contrary, when used with a DM, a LGP do not show performance improvements.

text: Linear Genetic Programming with Experience A novel method of using Machine Learning (ML) algorithms to improve the performance of Linear Genetic Programming (LGP) is studied. In this study, structures used to organize the trained ML models are called Experience Models (EM). They are used for different mutate actions of the mutation operator in LGP. The purpose of using EM is to regulate the random search performed by the mutation operator. The aim of using EMs is to let the suitable candidates have higher chances to be selected.
In this study, two sources of knowledge are used to create the training sets that are used to train ML models. The first source is the pre-existing knowledge of symbolic regression. This knowledge reflects the effect of adding one math function segment to another math function segment. The second source is the knowledge generated during the evolution of LGP. This knowledge reflects the effect of using different gene components at different chromosome indexes on the overall fitness. Based on these two sources of knowledge, two types of EM are designed. They are Static Model (SM) and Dynamic Model (DM). The SM uses ML models trained with the first knowledge source. A SM tries to achieve the aim of using an EM by reducing the size of the candidate sets used by the increase action of the mutation operator. The DM uses ML models trained with the second knowledge source. A DM tries to achieve the aim of using an EM by creating distributions of gene component types, which can reflect the information in the second knowledge source, for change action of the mutation operator. In this study, SM is used only for increase action in the mutation operator; DM is used only for change action in the mutation operator.
From the experiment results, if compared with a LGP, when a LGP using a SM, it tends to need fewer generations to have a hit, at the same time achieving similar mean best fitness. In contrary, when used with a DM, a LGP do not show performance improvements.

year: 2015

title: Dietary supplementation and intragastric infusions of L-tryptophan reduce food intake

authors: Aidney, Fraser Charles

subjects: L-tryptophan

abstract: Select free amino acids have been suggested to promote early satiation. Initial studies indicate that L-tryptophan may play an important role in reducing appetite. The current set of experiments examined whether dietary and intragastrically administered L-tryptophan decreases food consumption and whether this effect is specific to eating stimulated by energy (calorie) needs or by pleasant taste (reward). A link between a satiating action of L-tryptophan and activity of the anorexigenic oxytocin circuit has also been investigated. Supplementation of milk formula-based diets with tryptophan reduced energy deprivation-induced consumption of these formulas in mice. Tryptophan enrichment had no effect on water intake, which precludes the involvement of taste- or thirst-related mechanisms in tryptophan-driven hypophagia. Intragastrically administered L-tryptophan decreased deprivation-induced chow intake. It also reduced hedonics-driven consumption of palatable saccharin and milk, but not of sucrose solutions in non-deprived mice, suggesting a link with feeding reward mechanisms unrelated to sucrose. Finally, oxytocin receptor blockade with very low doses of an antagonist just prior to intragastric L-tryptophan administration, completely abolished early termination of deprivation-induced food intake by this amino acid. Overall, the data indicate that dietary supplementation and intragastric delivery of free L-tryptophan reduce eating behaviour stimulated by energy needs and palatability, and that the effect of L-tryptophan is mediated by the anorexigenic oxytocin system.

text: Dietary supplementation and intragastric infusions of L-tryptophan reduce food intake Select free amino acids have been suggested to promote early satiation. Initial studies indicate that L-tryptophan may play an important role in reducing appetite. The current set of experiments examined whether dietary and intragastrically administered L-tryptophan decreases food consumption and whether this effect is specific to eating stimulated by energy (calorie) needs or by pleasant taste (reward). A link between a satiating action of L-tryptophan and activity of the anorexigenic oxytocin circuit has also been investigated. Supplementation of milk formula-based diets with tryptophan reduced energy deprivation-induced consumption of these formulas in mice. Tryptophan enrichment had no effect on water intake, which precludes the involvement of taste- or thirst-related mechanisms in tryptophan-driven hypophagia. Intragastrically administered L-tryptophan decreased deprivation-induced chow intake. It also reduced hedonics-driven consumption of palatable saccharin and milk, but not of sucrose solutions in non-deprived mice, suggesting a link with feeding reward mechanisms unrelated to sucrose. Finally, oxytocin receptor blockade with very low doses of an antagonist just prior to intragastric L-tryptophan administration, completely abolished early termination of deprivation-induced food intake by this amino acid. Overall, the data indicate that dietary supplementation and intragastric delivery of free L-tryptophan reduce eating behaviour stimulated by energy needs and palatability, and that the effect of L-tryptophan is mediated by the anorexigenic oxytocin system.

year: 2016

title: Barriers and facilitators to Oranga Tamariki access: Wāhine voices from Te Whakaruruhau

authors: Mcleay, Ana

abstract: This thesis examines how wāhine supported by Te Whakaruruhau Waikato Women’s Refuge experience Oranga Tamariki (OT) in the context of intimate partner violence (IPV), and what barriers and facilitators shape their access to services. Within a Community-Based Participatory Research approach, influenced by Kaupapa Māori and Mana Wahine principles, qualitative data were collected through semi-structured, kanohi ki te kanohi interviews with six wāhine and kaimahi. Reflexive thematic analysis identified seven themes, grouped into two overarching clusters: barriers and facilitators to OT access. Barriers were pervasive and cumulative, encompassing relational harm, negligence, fear and risk, and cultural tokenism. Facilitators - collaborative advocacy, strengths-based practice, and procedural justice - were comparatively rare and often dependent on external supports rather than systemic provision.

Mapping these findings against Te Hā o Whānau, an access framework, revealed that barriers emerged where tikanga manaakitanga, tikanga whakawhanaungatanga, and tikanga rangatiratanga were absent, while facilitators aligned with their enactment. Te Hā o Whānau conceptualises access as a relational and culturally grounded process inseparable from wellbeing, making it both conceptually robust and uniquely suited to Aotearoa. The analysis demonstrates that OT, as currently structured, undermines whānau wellbeing through systemic practices that erode mana, restrict autonomy, and compromise safety. In the immediate term, strengthened collaborative advocacy offers some protection and support, but meaningful change requires systemic transformation.

Future research should examine how Te Hā o Whānau might be further operationalised across different service contexts and explore experiences of wāhine and whānau with OT in a variety of contexts to build a fuller understanding of access and wellbeing in child welfare.

text: Barriers and facilitators to Oranga Tamariki access: Wāhine voices from Te Whakaruruhau This thesis examines how wāhine supported by Te Whakaruruhau Waikato Women’s Refuge experience Oranga Tamariki (OT) in the context of intimate partner violence (IPV), and what barriers and facilitators shape their access to services. Within a Community-Based Participatory Research approach, influenced by Kaupapa Māori and Mana Wahine principles, qualitative data were collected through semi-structured, kanohi ki te kanohi interviews with six wāhine and kaimahi. Reflexive thematic analysis identified seven themes, grouped into two overarching clusters: barriers and facilitators to OT access. Barriers were pervasive and cumulative, encompassing relational harm, negligence, fear and risk, and cultural tokenism. Facilitators - collaborative advocacy, strengths-based practice, and procedural justice - were comparatively rare and often dependent on external supports rather than systemic provision.

Mapping these findings against Te Hā o Whānau, an access framework, revealed that barriers emerged where tikanga manaakitanga, tikanga whakawhanaungatanga, and tikanga rangatiratanga were absent, while facilitators aligned with their enactment. Te Hā o Whānau conceptualises access as a relational and culturally grounded process inseparable from wellbeing, making it both conceptually robust and uniquely suited to Aotearoa. The analysis demonstrates that OT, as currently structured, undermines whānau wellbeing through systemic practices that erode mana, restrict autonomy, and compromise safety. In the immediate term, strengthened collaborative advocacy offers some protection and support, but meaningful change requires systemic transformation.

Future research should examine how Te Hā o Whānau might be further operationalised across different service contexts and explore experiences of wāhine and whānau with OT in a variety of contexts to build a fuller understanding of access and wellbeing in child welfare.

year: 2025