155 resultados para Random utility


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Workplace injuries are common and destructive to persons, organisations, and society. Various instruments presently exist that are designed to assess the factors underlying workplace injury. The study reports on the construct and predictive validity of a 46-item instrument, the safety perception survey (SPS), currently used to assess safety climate in industrial organisations throughout Australia. Initially, factor analysis was conducted on the data from a sample of 1238 employees from nine organisations, which indicated a one-factor solution, was the best fit. A structural equation model (SEM) linking injury rates to the safety climate measure for 16 sub-groups of six industrial organisations indicated that the measure contributed just 23% of the variance in injury rates. Interestingly, the results indicated that the number of employees was a better and more significant predictor of injury (R2 = 0.48). It is proposed that the SPS as is would need to be modified significantly from its current form to produce improvements in validity, as in its current form the survey is no more predictive of injury than organisational size. Future research into safety climate measures should incorporate predictive validity analysis on injury rates, as for many organisations; this is a performance outcome measure.

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Computer simulation is a powerful tool to predict microstructure and its evolution in dynamic and post-dynamic recrystallization. CAFE proposed as an appropriate approach by combining finite element (FE) method and cellular automata (CA) for recrystallization simulation. In the current study, a random grid cellular automaton (CA), as micro-scale model, based on finite element (FE), as macro-scale method, has been used to study initial and evolving microstructural features; including nuclei densities, dislocation densities, grain size and grain boundary movement during dynamic recrystallization in a C-Mn steel. An optimized relation has been established between mechanical variables and evolving microstructure features during recrystallization and grain growth. In this model, the microstructure is defined as cells located within grains and grain boundaries while dislocations are randomly dispersed throughout microstructure. Changes of dislocation density during deformation are described considering hardening, recovery and recrystallization. Recrystallization is assumed to initiate near grain boundaries and nucleation rate was considered constant (site-saturated condition). The model produced a mathematical formulation which captured the initial and evolving microstructural entities and linked their effects to measurable macroscopic variables (e.g. stress).

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This paper presents a random forest-based face image classification method. The random forest is an ensemble learning method that grows many classification trees. Each tree gives a classification. The forest selects the classification that has the most votes. Three experiments are performed. The random forest-based method together with several existing approaches are trained and evaluated. The experimental results are presented and discussed.

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A strategy for the preparation of the otherwise difficult to obtain binary organometallic oxides containing two heavy main group elements is described and exemplified by the synthesis of [(p-MeOC6H4)2Te(OSnt-Bu2OH)2]2.

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Three alternative monetary models of exchange rate are tested using data on the Italian lira - US doIIar exchange rate. II is shown that up to the early 1990s these economic models perform better than the random walk model in out-of-sample forecasts.

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Within the discipline of community psychology there is debate as to the dimensions underlying the construct psychological sense of community (PSOC). One of the few theoretical discussions is that of McMillan and Chavis (1986), who hypothesized four dimensions: Belonging; Fulfillment of Needs; Influence; and Shared Connections. Discussion has also emerged in the literature regarding the role of identification within PSOC. It has been suggested that differences in PSOC may be understood in terms of the degree to which members identify with their community (Fisher & Sonn, 1999). However, few studies have explored the place of identification in PSOC. In addition, while PSOC has been applied to both communities of interest and geographical communities, little research has looked in depth at PSOC within communities of interest. The current study therefore explored PSOC in science fiction fandom, a community of interest with membership from all over the world, by means of a questionnaire distributed at an international science fiction convention (N = 359). In an endeavor to clarify the underlying dimensions of PSOC, the questionnaire included several measures of PSOC, and measures of identification with the community. Results showed that science fiction fandom reported high levels of PSOC. Support emerged for McMillan and Chavis' (1986) four dimensions of PSOC, with the addition of a fifth dimension, that of Conscious Identification. These results, and implications for PSOC research, are discussed.

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There have been few longitudinal studies of quality of life in patients with all stages of lung cancer, particularly those that have included measures of utility. The purpose of this study was to examine the psychometric properties of the Assessment of Quality of Life instrument (AQoL) in patients with lung cancer. The AQoL is a health-related quality of life questionnaire and provides a descriptive system for a multi-attribute utility instrument (MAU), so that scores can be used in cost-utility evaluations. In the present study the reliability (internal consistency) of the AQoL was examined and the concurrent validity was assessed using the Medical Outcomes 36-item Short Form Health Survey (SF-36) as the comparator instrument. The sensitivity to different health states of the AQoL and the responsiveness to change over time was also examined. A prospective, non-experimental cohort study was undertaken. Ninety-two participants with all stages of lung cancer were recruited from a tertiary multi-disciplinary lung cancer clinic. Ninety participants had non-small cell lung cancer (NSCLC) and two had limited stage small cell lung cancer. The AQOL and SF-36 surveys were administered concurrently at baseline. In patients with NSCLC the surveys were then repeated 3 and 6 months later. Correlations between the baseline AQoL summary scales and SF-36 summary scales support the divergent and convergent validity of the AQoL. Reliability was also found to be sufficient (Cronbach's Alpha = 0.76). In addition, in patients with inoperable NSCLC, baseline AQoL scores were found to be predictive of survival at 6 months in Cox proportional hazards multivariate analysis. However, the physical components summary score of the SF-36 was more sensitive to differences in health states between patients with different stages of NSCLC at 6 months of follow-up and more responsive to change over time in both operable and inoperable patients with NSCLC than the AQoL. The findings support the construct validity and reliability of the AQoL in this population. However, there remains some uncertainty about whether the AQoL has sufficient sensitivity to different health states in this population. Further studies using other MAU instruments may determine whether alternative instruments are more sensitive to different health states in individuals with lung cancer.

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Resource management decisions influence not only the output of the economy but also the distribution of utility between groups within the community. The theory of Benefit Cost Analysis provides a means of incorporating this distributional change through the application of distributional or welfare weights. This paper reports the results of research designed to estimate distributional weights suitable for inclusion in a Benefit Cost Analysis framework. The findings of a choice modelling experiment estimating community preferences with respect to intergenerational utility distribution are presented to illustrate this innovative application of a stated preference technique.

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The purpose of this paper is to describe a process for sampling specific domain name zones on the World Wide Web. Because of the size of the Web, sampling strategies must be employed in order to effectively model and study the Web business environment.  This paper discusses Various efforts employed to sample the Web, which ranged from random generation of Internet Protocol Addresses and domain names, to the process finally
employed to create descriptive models of the dot-com domain name zones. The paper suggests that sampling the Web Top Level Domains offers a reasonable alternative for business researchers because it requires only familiarity with the use of the simple Web utilities such as File Transfer
Protocols to obtain initial domain name listings.

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This study describes the use of landscape transition analysis as a means for effective basin management. Land cover transitions from 1995 to 2002 were analyzed using a cross-tabulation matrix for an important economic zone in south-west Victoria, Australia. Specifically, the matrix was used to determine whether the transitions were random or systematic. Random landscape transitions occur when a land cover replaces other land covers in proportion to their availability. Systematic landscape transitions occur when there are deviations from random patterns, and land use types ‘target’ other land use types for replacement. The analysis was conducted with 11 land cover categories and showed that dryland pastures have been systematically losing area to dryland crops and blue gum (Eucalyptus globulus) plantations. Dryland crops have systematically expanded in the north-east of the catchment, an area where increasing in-stream salinization has occurred concurrently with this transition. The systematic expansion of the blue gum plantations has been predominantly in the south-west of the catchment and has the potential to reduce stream flows and groundwater recharge in an already water-stressed region, as blue gums use more water than the dryland pastures they are replacing. All other transitions were largely random. These findings have implications for land use planning in the study area for regional water balance and revegetation strategies. Landscape transition analysis is a cost-effective means of contributing to the management of water resources at a regional scale, and is highly recommended for future basin planning.

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Background Subjective wellbeing (SWB) in people with intellectual disabilities has been the focus of increased interest in the identification of support needs and as an outcome measure for interventions and service delivery evaluations. It is therefore important to conduct further research in this area, and to develop appropriate scales to measure SWB.

Methods A new scale, the Personal Wellbeing Index-Intellectual Disability (PWI-ID) was administered to 114 adults with mild (n = 82) or moderate (n = 32) level ID in Victoria, Australia.

Results The PWI-ID demonstrated good reliability and validity. A comparison of the findings with previous research indicates that participants' SWB levels are within the normative range, and are similar to those reported by the general population.

Conclusions The results support the notion that individuals with ID do not experience life quality lower than normal, which can be explained theoretically by the Theory of Subjective Wellbeing Homeostasis. The use of the PWI-ID may ultimately assist in ensuring that the needs of people with ID are being met and inform the planning and delivery of congruent resources and services.

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Objective: This study had two aims: (1) to examine pregnant women's alcohol consumption across time from prepregnancy until childbirth and (2) to explore whether prepregnancy drinking and intention to drink predict prenatal alcohol consumption while controlling for relevant demographic variables.

Methods: At 17–21 weeks, 248 pregnant women completed questions about demographics, intention to drink alcohol during the subsequent pregnancy, and retrospective measures of prepregnancy and early pregnancy consumption. After this time, calendars were sent fortnightly assessing daily alcohol consumption until birth.

Results: For women who drank both prepregnancy and postpregnancy confirmation, average fortnight alcohol consumption in the first weeks of pregnancy was lower than during prepregnancy, and consumption continued to decrease between gestational weeks 1 and 8, particularly following pregnancy confirmation, after which it remained relatively stable. When predicting whether women drank in late pregnancy, intention accounted for unique variance after controlling for income and prepregnancy drinking. For women who drank after pregnancy confirmation, prepregnancy drinking quantity significantly predicted intention to drink, which in turn predicted fortnight alcohol consumption in later pregnancy, after controlling for prepregnancy drinking and income.

Conclusions: Findings highlight the need to measure alcohol consumption at multiple time points across pregnancy, the need for educating and supporting women to reduce consumption when planning pregnancies, and the usefulness of intention to drink as a predictor of drinking during pregnancy.

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Federal government changes to the funding of doctoral students have focused the attention of university management on their completion rates. The aims of this paper are to inform the allocation of institutional resources in a manner that improves the likelihood of timely doctoral completions and to highlight a process that can also be used for analyses of other key indicators of progression and attrition. The analyses and model development used national data readily available to all universities, which are collected in a standard approach through the Graduate Destinations Survey (GDS). The findings show that the most important variable for timely completion was attendance (full-time compared with part-time), whereby in terms of full-time equivalent (FTE) years of study, part-time students were far more likely to complete quickly than full-time students. For the full-time students, the key predictors of timely completion were residency, field of study and English-speaking background (ESB). The timeliness of part-time students was predicted by field of study and ESB. This study confirms that there is considerable variation by discipline for timely doctoral completions. The pragmatic application and prospective test of the derived models present a variety of opportunities for research student administrators. For example, those full-time students scoring highly represented a concentration of timely graduates more than 7.5 times higher than the lowest-scoring group - almost an order of magnitude of difference. In short, university management could gain tremendous value from more widely using the data available.