4,117 research outputs found

    Decrypting The Java Gene Pool: Predicting Objects' Lifetimes with Micro-patterns

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    Pretenuring long-lived and immortal objects into infrequently or never collected regions reduces garbage collection costs significantly. However, extant approaches either require computationally expensive, application-specific, off-line profiling, or consider only allocation sites common to all programs, i.e. invoked by the virtual machine rather than application programs. In contrast, we show how a simple program analysis, combined with an object lifetime knowledge bank, can be exploited to match both runtime system and application program structure with object lifetimes. The complexity of the analysis is linear in the size of the program, so need not be run ahead of time. We obtain performance gains between 6-77% in GC time against a generational copying collector for several SPEC jvm98 programs

    Joint inversion scheme with an adaptive coupling strategy - applications on synthetic and real data sets

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    Joint inversion strategies for geophysical data have become increasingly popular since they allow to combine complementary information from different data sets in an efficient way. However, for joint inversion algorithms that use methods that are sensitive to different parameters it is important that they are not restricted to specific survey arrays and subsurface conditions. Hence, joint inversion schemes are needed that 1) adequately balance data from the different methods and 2) use links between the parameter models that are suited for a wide range of applications. Here, we combine MT, seismic tomography and gravity data in a non-linear joint inversion that accounts for these critical issues. Data from the different methods are inverted separately and are joined through constrains accounting for parameter relationships. An advantage of performing the inversions separately (and not together in one matrix) is that no relative weighting between the data sets is required. To avoid that the convergence behavior of the inversions is profoundly disturbed by the coupling, the strengths of the associated constraints are re-adjusted at each iteration. As criteria to control the adaption of the coupling strengths we used a general version of the well-known discrepancy principle. Adaption of the coupling strengths makes the joint inversion scheme also applicable to subsurface conditions, for which the assumed relationships are only a rough first order approximation. So, the coupling between the different parameter models is automatically reduced if for some structures the true rock property behaviors differ significantly from the assumed relationships (e.g. the atypical density-velocity behavior of salt). We have tested our scheme first on different synthetic 2-D models for which the assumed parameter relationships are everywhere valid. We observe that the adaption of the coupling strengths makes the convergence of the inversions very robust and that the final results are close to the true models. In a next step the scheme has been applied on models for which the assumed parameter relationships are invalid for some structures. For these structures deviations from the relationships are present in the final results; however, for the remaining structures the relative behaviors of the physical parameters are still approximately described by the assumed relationship. Finally, we applied our joint inversion scheme on seismic, MT and gravity data collected offshore the Faroe Islands, where basalt intrusions are present

    Issues in evaluating the costs and cost-effectiveness of Cognitive Behavioural Therapy for overweight/obese adolescents, CHERE Working Paper 2009/1

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    Economic evaluation is the systematic assessment of the costs and consequences of alternative courses of action. In health and healthcare, the results can be used to inform clinicians and policy makers about the relative cost-effectiveness of options under consideration [1]. Many economic evaluations are undertaken alongside randomised controlled trials (RCTs); the advantages of this approach are that i) prospective, accurate data can be collected on costs and effects and ii) appropriate outcome measures for use in economic evaluation can be chosen. The outcome of an economic evaluation is usually described as a ratio of the costs and effects ? often called the incremental cost-effectiveness ratio (ICER). The ICER is determined by calculating the differences in the costs and effects of both intervention and control groups and dividing the former by the latter. In designing an economic evaluation, the important questions to resolve are: which costs should be included and which outcome measures are most appropriate for estimating the cost-effectiveness ratio? In 2005, the Australian Technology Network of Universities funded the Centre for Metabolic Fitness (CMF) through a competitive, peer-reviewed process. The aims of the centre are to develop and evaluate diet and exercise interventions to counteract metabolic syndrome and assess their acceptability by target community groups. Metabolic syndrome is a cluster of metabolically determined risk factors associated with obesity (e.g. hypertension, impaired blood glucose etc). A number of collaborative projects have been developed within the centre, one of which is the CHOOSE HEALTH project. As part of this project, the effectiveness of cognitive behavioural therapy (CBT) as an intervention for overweight or obese adolescents has been trialled at the University of RMIT by Leah Brennan and the University of South Australia by Margarita Tsiros, as part of their post-graduate studies1. Subsequently, it has been decided to add an economic component to this work. Trials of the effectiveness and cost-effectiveness of different means of delivering cognitive behaviourally based weight management programs are planned2. This paper reports the results of investigations into the two questions which need to be addressed prior to undertaking a formal economic evaluation of the CHOOSE HEALTH program: i) what costs should be included and ii) which measures of outcome are suitable for estimating an ICER in this context. The paper is organised in four sections. Following the introduction (section 1) and brief descriptions of the background to and context in which the program was planned (section 2), details of the RMIT trial design and results are provided in section 3. In the final section (section 4), a cost model is presented and the implications of the outcomes used in the initial trials of the effectiveness are discussed in relation to designing a prospective economic evaluation of the CHOOSE HEALTH program.costs, economic evaluation, cognitive behavioural therapy (CBT), adolescent obesity, Australia

    It's what's expected: genetic testing for inherited conditions, CHERE Discussion Paper No 46

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    The development of new genetic technology brings with it responsibility for evaluating the effectiveness and efficiency of testing programs, including gaining an understanding of the value of information. This study examined the factors individuals took into account when making decisions about having a genetic test for Tay Sachs Disease. Fifteen people participated in an in-depth interview as they attended a clinic for genetic testing. A thematic analysis of the data was undertaken. Participants were most influenced to have testing by personal factors: e.g. ethnic background and desire to have children. Disease characteristics were also important. The results informed the development of a Stated Preference Discrete Choice (SPDCM) experiment. Participants were motivated to have testing by a need for reassurance and certainty. Thus, information was an important outcome for them. The results of the SPDCM experiment indicate that participants valued information positively thus providing support for the findings of the qualitative research.Genetic testing, Tay Sachs disease, Discrete choice experiment

    Abstracts of Recent Cases

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    Security Transactions--Uniform Trust Receipts Act

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    Death and Crippling in the Marketing of Swine

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    The purpose of this investigation is to determine the incidence of death and crippling and its relationship to total numbers of swine marketed, to graphically illustrate annual, seasonal, monthly, weekly and daily patterns of swine marketing, death and injury, to relate length of-haul to incidence of loss and, to study the combined effect of year, month and distance hauled on rate of loss and damage
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