103 research outputs found

    Support for Learning Synthesiser Programming

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    When learning an instrument, students often like to emulate the sound and style of their favourite performers. The learning process takes many years of study and practice. In the case of synthesisers the vast parameter space involved can be daunting and unintuitive to the novice making it hard to define their desired sound and difficult to understand how it was achieved. Previous research has produced methods for automatically determining an appropriate parameter set to produce a desired sound but this can still require many parameters and does not explain or demonstrate the effect of particular parameters on the resulting sound. As a first step to solving this problem, this paper presents a new approach to searching the synthesiser parameter space to find a sound, reformulating it as a multi-objective optimisation problem (MOOP) where two competing objectives (closeness of perceived sonic match and number of parameters) are considered. As a proof-of-concept a pareto-optimal search algorithm (NSGA-II) is applied to CSound patches of varying complexity to generate a pareto-front of non-dominating (i.e. ”equally good”) solutions. The results offer insight into the extent to which the size and nature of parameter sets can be reduced whilst still retaining an acceptable degree of perceived sonic match between target and candidate sound

    Age Differences in Intra-Individual Variability in Simple and Choice Reaction Time: Systematic Review and Meta-Analysis

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    Intra-individual variability in reaction time (RT IIV) is considered to be an index of central nervous system functioning. Such variability is elevated in neurodegenerative diseases or following traumatic brain injury. It has also been suggested to increase with age in healthy ageing.To investigate and quantify age differences in RT IIV in healthy ageing; to examine the effect of different tasks and procedures; to compare raw and mean-adjusted measures of RT IIV.Four electronic databases: PsycINFO, Medline, Web of Science and EMBASE, and hand searching of reference lists of relevant studies.English language journal articles, books or book chapters, containing quantitative empirical data on simple and/or choice RT IIV. Samples had to include younger (under 60 years) and older (60 years and above) human adults.Studies were evaluated in terms of sample representativeness and data treatment. Relevant data were extracted, using a specially-designed form, from the published report or obtained directly from the study authors. Age-group differences in raw and RT-mean-adjusted measures of simple and choice RT IIV were quantified using random effects meta-analyses.Older adults (60+ years) had greater RT IIV than younger (20-39) and middle-aged (40-59) adults. Age effects were larger in choice RT tasks than in simple RT tasks. For all measures of RT IIV, effect sizes were larger for the comparisons between older and younger adults than between older and middle-aged adults, indicating that the age-related increases in RT IIV are not limited to old age. Effect sizes were also larger for raw than for RT-mean-adjusted RT IIV measures.RT IIV is greater among older adults. Some (but not all) of the age-related increases in RT IIV are accounted for by the increased RT means

    Understanding treatment non-responders: A qualitative study of depressed adolescents' experiences of 'unsuccessful' psychotherapy

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    OBJECTIVES: This paper aimed to explore the experiences of depressed adolescents who completed but did not 'respond' to standard psychotherapy, based on a lack of improvement in pre-post symptoms scores. DESIGN: This was a qualitative study employing interpretative phenomenological analysis (IPA). METHOD: Seventy-seven adolescents with moderate to severe depression were interviewed as part of a qualitative arm of a randomised controlled trial. Five adolescents' post-treatment interviews were purposively sampled, based on lack of improvement on pre-post symptom scores, and adolescents still scoring above the clinical threshold for depression. The interviews were analysed using IPA. RESULTS: Adolescents made sense of their depression as part of their identity and held negative expectations of therapy. Some aspects of therapy brought up intolerable feelings that contributed to disengagement in the therapeutic process and culminated in disappointing and hopeless endings. On the other hand, where a stronger therapeutic relationship was developed, some participants experienced certain improvements. CONCLUSIONS: Findings highlight how actively exploring the adolescent's therapy expectations, developing a strong early therapeutic relationship and being mindful of the potential impact of endings are important in therapeutic work with adolescents with depression, especially where they may have a strong sense of hopelessness and self-criticism. Moreover, the finding that adolescents experienced improvements in other domains despite a lack of symptom reduction highlights the need to review how treatment outcomes are currently defined. Integrating individual perspectives of therapy with quantitative outcome measures can provide a more nuanced insight of treatment effects

    Fracture modelling of magnesium sheet alloy AZ31 for deep drawing processes at elevated temperatures

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    Today, the reduction of CO2 emissions is essential to meet global climate requirements. In this context, a reduction in vehicle weight is the most efficient way to reduce the fuel consumption of a passenger car. Magnesium combines relatively high strength with low weight and is therefore an interesting construction material for lightweight solutions. In numerical process design, it is essential to be aware of the forming capacity of a material. The common method to describe the failure behaviour is the use of forming limit curve (FLC). Stress-based models offer the advantage of a strain path consideration and an extension in the area of shearing and compression. In this paper a stress-based damage model, Modified Mohr-Coulomb (MMC), was parameterized by IFUM Butterfly-Tests for an AZ31 magnesium sheet alloy under consideration of elevated process temperatures. For this purpose, the tests were carried out at different stress states and temperatures using a specially designed testing device. In addition, forming limit curves were determined by Nakajima tests. Finally, both methods, MMC and FLC, were compared to an experimental deep-drawing test. This comparison showed that the MMC Model achieved significantly better results regarding the fracture prediction in this application case

    Stress-state dependent fracture characterisation and modelling of an AZ31 magnesium sheet alloy at elevated temperatures

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    Due to a high specific strength, magnesium alloys have a high potential to be considered for lightweight solutions in automotive industry. For the numerical design of forming processes, it is important to describe the yielding as well as the fracture behaviour of a material as precisely as possible. In order to fully characterise the fracture behaviour of an AZ31 magnesium sheet alloy at elevated temperatures, a heated test setup for uniaxial tensile machines was developed. The setup allows an adjustment of the load application angle whereby a stress variation is achieved in the centre of the specimen. In order to determine the fracture strain for different temperatures and for varying stress states, a shear stress specimen (also known as butterfly specimen) was considered to perform mechanical experiments by means of this setup. Using numerical simulations, the specific stress development and strain value in the fracture zone, which is needed to calibrate stress state fracture models, was determined for each loading angle and temperature. For this purpose, an orthotropic yield criterion CPB06, which is suitable for depiction of the particular flow behaviour of magnesium alloys (e. g. compression-tension asymmetry), was used. By this means, sufficient data for the calibration of common stress state based fracture models could be provided and the MMC- (Modified Mohr-Coulomb) fracture model was parameterised

    How do therapists assess suitability? A qualitative study exploring therapists' judgements of treatment suitability for depressed adolescents

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    BACKGROUND: Despite the need for a better understanding of treatment suitability, how it is determined by therapists in real-life practice is still unknown. The study aimed to explore how therapists working with depressed teenagers make judgements about treatment suitability across three treatment modalities: (a) Short-term Psychoanalytic Psychotherapy, (b) Cognitive Behaviour Therapy, and (c) Brief Psychosocial Intervention. METHODS: The study used a qualitative analysis within a randomised controlled trial. Therapists' judgements of treatment suitability were studied via an exploratory content analysis. This trial is registered with current controlled trials, number ISRCTN83033550. RESULTS AND DISCUSSION: A wide range of factors were considered in therapists' judgements of suitability, with significant variation in themes across treatment modalities. Although a much higher number of therapists judged the allocated treatment modality to be suitable to the client than not, many also indicated ambivalence and uncertainty towards their decision-making. This demonstrates a possibility that treatment suitability may be more accurately assessed as a continuum over multiple time points throughout treatment

    Evaluation of common tests for fracture characterisation of advanced high-strength sheet steels with the help of the FEA

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    The paper presents results of evaluation of common tests for fracture characterization of advanced high-strength sheet steels with the help of the FEA. The tests include three in-plane shear tests, two uniaxial tension tests, two plane strain tension tests and two equibiaxial tension tests. Three high-strength steels with different yield loci, strain hardening rates and strengths in three different thicknesses each were used. The evaluation was performed based on the spatial distribution of the equivalent plastic strain and damage variable in the specimen at the moment of crack initiation as well as on the time variation of the stress state at the crack initiation location. For in-plane shear, uniaxial tension and plane strain tension, no test can be unconditionally recommended as disadvantages of all studied tests in these groups cannot be neglected. However, in each of these groups, a test can be chosen, which represents an acceptable compromise between its advantages and disadvantages: the shear test on an IFUM butterfly specimen for in-plane shear, the tensile test on a holed specimen for uniaxial tension and the tensile test on a waisted specimen for plane strain tension. On the contrary, the bulge test on a circular specimen with a punch of Ø 100 mm can be unconditionally recommended for equibiaxial tension. In the future, optimisation of the studied tests for in-plane shear, uniaxial tension and plane strain tension appears to be necessary.FOST

    Experimental Characterization and Material Modelling of an AZ31 Magnesium Sheet Alloy at Elevated Temperatures under Consideration of the Tension-Compression Asymmetry

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    Magnesium sheet alloys have a great potential as a construction material in the aerospace and automotive industry. However, the current state of research regarding temperature dependent material parameters for the description of the plastic behaviour of magnesium sheet alloys is scarce in literature and accurate statements concerning yield criteria and appropriate characterization tests to describe the plastic behaviour of a magnesium sheet alloy at elevated temperatures in deep drawing processes are to define. Hence, in this paper the plastic behaviour of the well-established magnesium sheet alloy AZ31 has been characterized by means of convenient mechanical tests (e. g. tension, compression and biaxial tests) at temperatures between 180 and 230 °C. In this manner, anisotropic and hardening behaviour as well as differences between the tension-compression asymmetry of the yield locus have been estimated. Furthermore, using the evaluated data from the above mentioned tests, two different yield criteria have been parametrized; the commonly used Hill'48 and an orthotropic yield criterion, CPB2006, which was developed especially for materials with hexagonal close packed lattice structure and is able to describe an asymmetrical yielding behaviour regarding tensile and compressive stress states. Numerical simulations have been finally carried out with both yield functions in order to assess the accuracy of the material models

    IQ and Internalising Symptoms in Adolescents with ASD.

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    Funder: University of EdinburghIntelligence quotient (IQ), has been found to relate to the presence of internalising symptoms in autism spectrum disorder (ASD). This meta-analysis sought to clarify the direction of the relationship between IQ and two prevalent internalising symptoms, anxiety and depression, in adolescents with ASD. Secondly, this study aimed to highlight methodological factors contributing to inconsistent findings in existing research. Self-reported anxiety was found to be significantly higher in youth with a lower IQ, while depression was positively associated with IQ. Consequently, parents, schools and clinicians should be cautious of underestimating anxiety in youth with a lower IQ. However, care should also be taken to ensure adolescents with ASD without intellectual disabilities are not overlooked with regards to social and emotional support
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