5,515 research outputs found
Bat Swing Analysis in Cricket
No full textTechnology in sports has had great impact during the last two decades. A lot of time, human power and cost are involved in existing batting research methods. The reliability and usefulness of these outcomes is prone to error and dependent on the human ability. In this project, miniature, inexpensive, user and match-friendly inertial sensors were used to extract the cricket bat swing features. The data was validated through existing tools. The object of this work was to demonstrate that accelerometers offer significant advantages in cricket batting analysis. Experimental and theoretical work involved ball free and ball-hit swing profiles.
Bat swing was analysed using accelerometer sensors and was validated using a rigid pendulum. Good agreement was obtained between the measured angles by inclinometer and static sensor (r=0.99), and between the swing angles estimated from equation and dynamic sensor (r=0.88). Hits on the pivot arm showed the optimum contact location to maximize the energy transfer to the ball. A non-linear pendulum equation with moving pivot was solved numerically to model for swing angles in straight drive. The derived equation showed good agreement with the acceleration data (r=0.91). The effect of initial angular velocity, the radius of rotation and phase angle of the pivot on the acceleration profile were strongly correlated with the maximum acceleration peak (r≡0.99).Thesis (PhD Doctorate)Doctor of Philosophy (PhD)Griffith School of EngineeringScience, Environment, Engineering and TechnologyFull Tex
Activated Sludge Bioassays for Rapid Biochemical Oxygen Demand
No full textA number of recent studies have described new rapid biochemical oxygen demand (BOD) methods. However, most have not maintained the features that make the 5-day standard BOD assay particularly relevant to wastewater management – a high level of substrate bio-oxidation and use of wastewater treatment plant (WWTP) sludge as the biocatalyst. In a critical breakthrough, return activated sludge (RAS) from Coombabah WWTP, southeast Queensland, was successfully incorporated as the biocatalyst in a ferricyanide mediated-BOD (FM-BOD) bioassay. The bioassay was initially optimized for the measurement of highly variable and complex wastewaters, particularly trade wastes, by maximizing the analytical working range (10 – 170 mg BOD5 L-1) and extent of substrate degradation (96 ± 23% of measured BOD5 oxidation). A highly significant correlation (n = 35; slope = 1.07; R = 0.95; incubation time = 6 h) was found between this RAS FM-BOD and standard BOD5 assays using a range of real trade waste samples.
The activated sludge FM-BOD bioassay was re-examined with the goal of measuring low–mid range wastewaters (i.e. treated effluents and WWTP influents) that comprise the bulk of all BOD samples analyzed worldwide. All experimental parameters were re-optimized, primarily to improve the detection limit of the FM-BOD assay to approximate that of the standard BOD5 assay (i.e. ≈2 mg BOD5 L-1). Primary influent sludge (PIS) from Coombabah WWTP was the most favorable sludge trialed, with the new bioassay having an analytical range of 2 – 40 mg BOD5 L-1. A highly significant correlation (n = 33; slope = 0.94; R = 0.96; incubation time = 3 – 4 h) was observed between the PIS FM-BOD and standard BOD5 assays using a range of treated effluent, influent and grey water samples.Thesis (PhD Doctorate)Doctor of Philosophy (PhD)Griffith School of EnvironmentScience, Environment, Engineering and TechnologyFull Tex
Parents and Adolescent Depression: Evaluation of a Model and an Intervention Program for Parents
No full textAdolescent depression affects up to 24% of adolescents before adulthood and is linked with serious outcomes. However as only 25% of affected adolescents in Australia receive appropriate assistance the prevention of adolescent depression has a high priority. Risk and protective factors exist in the individual, family, school and society, but the connection between these factors is often uncertain. Prevention at the individual level has been found to be successful but despite the importance of family factors there is little research into prevention at the family level. Because of the difficulty in engaging parents in preventive interventions it has been suggested that convenient, flexible delivery interventions may achieve better penetration. This study evaluates in two stages the Resourceful Adolescent Parent Program (RAP-P), a positively-focused family-based intervention for parents which has been developed to fill the need for a universal preventive intervention for adolescent depression. Firstly the study evaluates the theoretical basis for RAP-P by developing and testing models linking the family-based psychosocial risk and protective factors for teenage depression that are addressed by RAP-P, and the family systems factors underpinning these. No previous models linking these variables could be found in the literature. The study then evaluates two formats of RAP-P, one of three facilitated workshops attended by parents; the other a videotaped flexible delivery format for use at home, developed to overcome parents' poor involvement in preventive programs. Participants were 242 adolescents in Year 8 and 361 of their parents, recruited from eleven schools in Brisbane, Australia. Schools were randomly allocated to one of three conditions: workshop intervention, video intervention and control. Adolescents and parents completed measures at pre-test, post-test and 15 month follow-up. Based on the current adolescent depression literature and Bowen Theory, four models were developed, tested using structural equation modeling and confirmed after minor revisions. The first model examined links between adolescents' depression and the family based risk factors of parent-adolescent conflict and adolescents' negative perceptions of their parents' interactions with them, and the protective factor of parental attachment. Other models, based on Bowen Theory, examined the trans-generational transmission of differentiation of self from the adolescents' grandparents (generation 1) to the adolescents' parents (generation 2) and the effects of parents' differentiation and anxiety on the third generation adolescents' perceptions of their mothers, attachment and depression. The second part of the study examined the implementation and efficacy of the two formats of RAP-P. Predictions that the convenience of the flexible delivery format of RAP-P would result in better recruitment and lower attrition than for the workshop format were not supported, with the flexible delivery format encountering poorer recruitment and higher attrition. Predictions that parents' evaluations of both formats would be equally positive were not supported; the flexible delivery format was consistently evaluated less positively than the workshop format. However parents perceived both formats to be of similar benefit to them. Parents in the intervention conditions were predicted to exhibit better differentiation and lower anxiety than those in the control condition, resulting in their adolescents experiencing less intense conflict over fewer issues and appraising their parents more positively, and consequently exhibiting better parental attachment and lower levels of depression. The level of improvement was predicted to be related to the level of parental engagement in the interventions. However parents and adolescents in the intervention conditions did not show any positive effects of the interventions at post-test or follow-up. Parents who were engaged in the interventions and their adolescents similarly did not show any measurable benefits from the intervention. Thus this study has found support through modeling for the theoretical basis for RAP-P. Parents' feedback strongly supported the overall thrust and ethos of RAP-P and particularly of the workshop format, indicating that the intervention targeted the right factors in the right way. However the interventions did not achieve measurable improvements for parents or adolescents within the time frame of the study. With models supporting the appropriateness of the measured variables it appears that the potency of the intervention was insufficient. Finally the study found that the use of a flexible delivery videotape intervention did not achieve its goal of increased participation and was still very costly of resources.Thesis (PhD Doctorate)Doctor of Philosophy (PhD)School of Applied PsychologyFull Tex
TCCON data from Wollongong (AU), Release GGG2014.R0
No full textThe Total Carbon Column Observing Network (TCCON) is a network of ground-based Fourier Transform Spectrometers that record direct solar absorption spectra of the atmosphere in the near-infrared. From these spectra, accurate and precise column-averaged abundances of atmospheric constituents including CO2, CH4, N2O, HF, CO, H2O, and HDO, are retrieved. This data set contains observations from the TCCON station at Wollongong, Australia.Contact person: David Griffith [email protected]
Genetic structure and life history variation in a cryptic fish species complex, Australian smelt (Retropinna semoni) across south-east Queensland, Australia
No full textGenerally freshwater fish exhibit higher levels of genetic structuring between spatially distinct populations than marine species due to the presence of natural and artificial barriers to dispersal in freshwater ecosystems. In addition, freshwater species are not able to move between populations that are separated by either terrestrial or marine habitat. Diadromy constrains the development of genetic structuring, even among geographically isolated populations due to potential connectivity via movement through the sea. As a result, higher levels of gene flow and lower population structuring tend to be observed in diadromous fishes than freshwater species.
The Australian smelt (Retropinna semoni) is a native fish species complex widely distributed across coastal and inland drainages of south-eastern Australia. Recently, a complex of five or more cryptic species of Australian smelt has been recognized throughout their geographic range based on genetic studies. Variation in life history strategies has been observed in many cryptic fish species and multiple life history patterns were also found in southern smelt lineages (Retropinna sp.) where mainland Australian populations contain diadromous and wholly freshwater individuals and Tasmanian populations contain estuarine individuals. Despite the populations of southern smelt containing diadromous individuals, strong genetic structuring and low levels of connectivity were reported in at least some populations, which were suggested to result from apparently diadromous individuals being retained in the estuaries. It is possible that the different cryptic species may differ in life history. In the present study, I examine the genetic structure and life history variation of the South-east Queensland (SEQ) lineage of Australian smelt which was further subdivided into northern and southern lineages (SEQ-N, SEQ-S).
I used both molecular and ecological approaches to understand the pattern of genetic structure and life history variation in this species to compare with other members of the species complex. Prior to this task, twenty one polymorphic microsatellite primers were developed (Chapter 2), which were then used for species delimitation and population structure analysis.
In chapter 3, I used one mitochondrial gene (cyt b) and ten microsatellite loci to investigate patterns of genetic structuring in Australian smelt (R. semoni) and describe the genetic differences between these two cryptic lineages (SEQ-N and SEQ-S). These two lineages formed monophyletic clades in the mtDNA gene tree and among river phylogeographic structure was also evident within each clade. There was clear genetic divergence between the two lineages, suggesting that they have been separated historically by a hard barrier. Strong genetic structuring was observed from microsatellite analysis in both lineages (SEQ-S FST = 0.13; SEQ-N FST = 0.23) suggesting limited dispersal among rivers. Slightly lower levels of genetic structuring were observed in the SEQ-S lineage than the SEQ-N lineage. This might be the result of different microhabitat preferences between these two cryptic lineages (SEQ-N and SEQ-S), for example intolerance to water quality parameters. Another plausible explanation is that SEQ-S catchments may have been connected more recently and /or more often than those in the SEQ-N group during flood events. Contemporary movement of individuals only occurred between nearby sites within a river, but not between rivers, suggesting that if local extinctions occur in one or more of these rivers, then recolonization from elsewhere is unlikely to occur rapidly. Similarly, extinctions within a site are only likely to be recolonised from nearby sites in the same river.
In chapter 4, I used otolith micro-chemistry analysis to examine the life history patterns of smelt at the northern extent of their range and to identify any differences in migratory behaviour of the two lineages (SEQ-N and SEQ-S) in this region. Based on otolith core-to-edge transects of Sr:Ca and Ba:Ca, there was no evidence of marine residence for either lineage suggesting that both are non-diadromous. This contrasts with the two southern smelt species, in which both exhibit evidence of diadromous movement of individuals within some populations.
Significant differences in multi-elemental otolith chemistry signatures were observed among rivers and between paired sites within some rivers, suggesting no exchange of individuals among catchments and limited dispersal of individuals over large spatial scales within a river. This is almost certainly the result of the marine habitat conditions along the coastal drainages which isolate rivers and restrict movement of fish between them, combined with some limited dispersal within a river. In addition, movement of fish may also be precluded due to anthropogenic migration barriers within river catchments.
This study has presented a holistic view of population structure using ecological and genetic markers and revealed that R. semoni is highly structured across south-east Queensland from the Mary River to Currumbin Creek. Genetic analysis delivers the general framework for applying ecological methods and substantial information regarding exchange between populations. Sensitive ecological methods such as otolith chemistry provide resolution of the fine-scale spatial separation within and between sample collection locations because movements within an individual lifetime can be inferred. The results of the present study emphasise the advantages of using complementary methods to evaluate the connectivity of fish populations. The combination of otolith chemistry and molecular markers provided insights into the role of migration in structuring smelt populations over a range of temporal and spatial scales. Overall, the current study furnished new insights into the population genetic structure and life history patterns of Australian smelt, which has significant implications for the sustainable management and conservation of this ecologically variable species along coastal drainages in south-east Queensland.Thesis (PhD Doctorate)Doctor of Philosophy (PhD)School of Environment and ScScience, Environment, Engineering and TechnologyFull Tex
Improving the Utility of the Tower of London, a Neuropsychological Test of Planning
No full textThe utility of a popular test of planning, the Tower of London (TOL), was improved by addressing its limitations. The ceiling effect of the most commonly used version was removed by modifying the materials to increase item difficulty. To improve reliability, psychometric criteria were used to select the test items. An initial pool of 33 problems was administered to 65 children (M = 6.92 years, SD = 1.08) and 73 adults (M = 43.62 years, SD = 19.96) to derive 11 items of graded difficulty and maximal item discrimination. When these items were administered to 33 undergraduates (M = 26.10 years, SD = 9.79), the single item which did not retain its difficulty level was removed. Although low, the internal consistency in this sample (split-half r = .39) was higher than that of the TOL (Cronbach's alpha = .30) which was administered to 23 undergraduates (M = 25.61 years, SD = 8.69).
Normative data for the modified version (the TOL4) were collected for a total of 447 people aged between 5 and 53 years. The split-half reliability in this sample was acceptable (r = .60), as was the 1-month test-retest reliability of .71 for a sample of 61 adults and children (M = 26.08 years, SD = 13.98). Although there was a slight practice effect, F(1,60) = 6.80, p = .01, the improvement was not clinically important (Mtime1 = 20.59, SD = 4.34; Mtime2 = 21.49, SD = 3.16).
The construct validity of the total score as a measure of planning was demonstrated in three ways. First, the developmental improvement in the normative sample was consistent with both cognitive theory and previous research with the TOL. Second, in a sample of 73 undergraduates (M = 24.77 years, SD = 8.39) the total score correlated with measures of planning (Tinkertoy Test, r = .28, p < .05; Porteus Mazes; r = -.27, p < .05), but not with measures of other abilities, such as concept formation, verbal fluency, switching and memory. Finally, in a principal components analysis with the same sample, the total score loaded with a measure from the Porteus Mazes on a Planning component. In contrast, the planning time measure had a different developmental trajectory and different correlations. It appeared to measure response inhibition and the speed of encoding and conceptualising problems.
The results of this study have several implications for improving the assessment of planning in both clinical and experimental contexts. Most important, users can be confident that the TOL4 accurately measures aspects of planning ability, is suitable for repeated administrations with the same client, and is applicable across a wide age range.
Additional research to extend the norms to older adults and to evaluate criterion-related validity would further improve the utility of the TOL4.Thesis (Masters)Master of Philosophy (MPhil)School of Applied PsychologyGriffith HealthFull Tex
Reasoning with Plausible Causal Knowledge
No full textThis dissertation initiates a new direction in causal non-monotonic reasoning. We begin by reviewing commonly proposed and adopted principles of causal non-monotonic reasoning, and determine their suitability for characterising causal non-monotonic reasoning in a general sense. From this review, a significant gap in the literature is identified: research in causal non-monotonic reasoning has so far been focused on the re-use of familiar mathematics, and not concerned with the intuition that underpins human causal reasoning. To fill this gap, we propose a new approach to causal non-monotonic reasoning: one that is motivated primarily by the accurate representation of how humans typically reason with cause and effect in day-to-day life. We call this new approach Plausible Causal Reasoning (PCR). We propose some new principles that help characterise PCR, and define a new formalism for causal non-monotonic reasoning. The new formalism is shown to: satisfy each of our new principles; reason correctly with some important examples; and be well-behaved with respect to the standard properties used to determine the acceptability of logical reasoning mechanisms. We also indicate possible avenues of future work that would further develop this new approach to causal non-monotonic reasoning.Thesis (PhD Doctorate)Doctor of Philosophy (PhD)School of Environment and ScScience, Environment, Engineering and TechnologyFull Tex
Reply to Comments by James R. Wait
No full textGriffith Sciences, Griffith School of EngineeringFull Tex
Modular Synthesis and the Unconscious: An Exploration of the Role of Technology and Self-Reflection in Sound Creation and Compositional Process
No full textThis practice-based research project explores electronic music-making with a modular synthesiser within the context of technologically mediated music composition, the philosophical foundations of such practices, and a personal, psychoanalytically informed perspective. Through improvisation, composition, performance, and reflective writing, the researcher's approach evolves through the processes of self-discovery and insight. The open-ended research aims to understand the sources of inspiration that inform the researcher's unique and distinct musical output and how this is shaped by philosophical and psychoanalytic considerations. The exegesis examines the history and core concepts of the instrument and genre, as well as the relevance of psychoanalytic theory to the composer's musical practice. The findings and conclusions from this research project are distilled into potential guidelines for others exploring similar avenues in electronic music-making. The insights gained from the combination of practical experience and theoretical exploration will provide valuable direction for future practitioners looking to incorporate technology, philosophy, and personal experiences into their own creative process. The submitted portfolio presents the work of a modular synthesiser musician and composer over the course of six years of doctoral study. The works capture the evolution of the composer's approach and modular system and demonstrate the transformative role of technology in musical performance and composition. The composer's process involves improvising and performing live to tape with minimal post-processing and embracing imperfections for both technical and conceptual reasons. The composer’s artistic practice, including the release of three albums and performance of various concerts, primarily focuses on beatless ambient electronic music created exclusively with the modular synthesiser. The theoretical engagement with this creative project explores the concept of surplus enjoyment in the context of music-making with a modular synthesiser. Using Lacanian theory, the researcher argues that the process of music-making with a modular synthesiser is characterized by a constant search for new modules and an endless cycle of desire, acquisition, and lack. This surplus enjoyment is linked to the instrument's future potential and serves to connect the subject with the desired object. Finally, the project considers the implications of surplus enjoyment for music composition and performance with a modular synthesiser, and the role of psychoanalysis in understanding this phenomenon.Thesis (PhD Doctorate)Doctor of Philosophy (PhD)Queensland ConservatoriumArts, Education and LawFull Tex
TCCON data from Darwin (AU), Release GGG2014.R0
No full textThe Total Carbon Column Observing Network (TCCON) is a network of ground-based Fourier Transform Spectrometers that record direct solar absorption spectra of the atmosphere in the near-infrared. From these spectra, accurate and precise column-averaged abundances of atmospheric constituents including CO2, CH4, N2O, HF, CO, H2O, and HDO, are retrieved. This data set contains observations from the TCCON station at Darwin, Australia.Contact person: David Griffith [email protected]
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