962 resultados para Bilinear Predictive Control


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Objectives: To examine whether the subjective quality of life (QOL) of elderly people is held under homeostatic control, and to investigate the role of perceived control and dispositional optimism in the maintenance of subjective QOL.
Method: 100 older people (M=75.6 years) and a control group of 107 younger people (M=20.1 years) completed a self-report survey.
Results: Both groups had a level of subjective QOL within the normal range. The older group reported higher levels of secondary control and optimism, but similar levels of primary control, as the younger group. Primary control and optimism predicted subjective QOL for both groups. Secondary control was a significant predictor (or the younger group, however it was only marginally significant for the older group. Optimism accounted for the most subjective QOL variance for both groups.
Conclusions: The finding that the subjective QOL of the older group lay within the normative range supports the proposal that their subjective QOL is being successfully maintained under bomeostatic control. However, they appear to have an increased reliance on secondary control. The fact that dispositional optimism captures the predictive variance of perceived control, is an important finding adding to the understanding of subjective QOL maintenance.

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While situational factors such as high workloads have been found to be predictive of burnout, not all people in the same work context develop burnout. This suggests that individual factors are implicated in susceptibility to burnout. We investigated the relationships between care type (acute/chronic), neuroticism, control (primary/secondary), and symptoms of burnout (exhaustion, cynicism, and reduced professional efficacy) amongst 21 chronic care nurses and 83 acute care nurses working in a public hospital in regional Australia. Similar levels of burnout symptomatology and neuroticism were found in each group of nurses, and neuroticism was found to be associated with exhaustion, cynicism, and reduced professional efficacy in the total sample of nurses. Our prediction that primary control would protect against burnout symptoms in acute care nurses was supported only for professional efficacy, and the prediction that secondary control would protect against burnout in chronic care nurses was not supported.

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‘Psychosocial problems’ are psychological problems that are regarded as resulting from the interaction between the adaptive capacities of individuals and the demands of their physical and social environments. Many different factors have been theoretically proposed, and empirically established, as predictors of a range of psychosocial problems in adolescents. However, a problem exists in that this literature appears to lack an integrative framework that has validity across the range of problems that are observed. The purpose of the current research is to propose and test a model that draws together three clusters of factors that are useful in predicting the incidence of adolescent psychosocial problems. These are family structural background factors, family functioning variables and control beliefs. Data were collected from 155 adolescent males aged between 12 and 19 by a single concurrent and retrospective self-report questionnaire. This included data about the respondent (age, involvements with mental health or juvenile justice agencies) and family structural background factors (days per week worked by mother/father, occupational status for mother/father, residential mobility, number of persons in the family home). The questionnaire also incorporated the Parental Bonding Instrument (Parker, Tupling & Brown, 1979) to quantify the levels of perceived parental care and overprotection, and an adaptation of the Parental Discipline Style Scale (Shaw & Scott, 1991), to assess punitive, love withdrawing and inductive discipline practices. In addition, the (Low) Self-control Scale (Grasmick, Tittle, Bursick & Arneklev, 1993) and the Locus of Control of Behaviour Scale (Craig, Franklin, & Andrews, 1984) were used to collect data concerning adolescents’ perceived behavioural self-control and locus of control. Finally, selected sub-scales of the Child Behavior Checklist Youth Self-Report (Achenbach, 1991b) were used to collect data on the incidence of social withdrawal, somatisation, anxiety and depression, aggression and delinquency among the respondents, and in aggregated form, the incidence of ‘total problems’ and internalising and externalising behaviours. Results indicated family structural background factors, family functioning variables and control beliefs possess limited predicted validity and that the usefulness of the proposed model varies between specific psychosocial problems. Family functioning variables were generally stronger predictors than family structural background factors, particularly for internalising behaviours. Of these, levels of parental care and overprotection were generally the strongest predictors. Perceived self-control and locus of control were also generally strong predictors, but were particularly powerful with respect to externalising behaviours. The strength of predictive relationships was observed to vary between specific internalising and externalising behaviours, suggesting that individual difference variables not assessed in the current research were differentially influential. Finally, the parental and individual characteristics that predicted maximal levels of adjustment (defined in terms of minimal levels of internalising and externalising behaviours) were explored and the correlates of various parenting style typologies (Parker et al., 1979) were investigated. These results strongly confirmed the importance of family functioning and control beliefs with respect to the prediction of internalising, externalising and well-adjusted behaviours. In all analyses, substantial proportions of the variance in the incidence of problem behaviours remain unexplained. The findings are examined in relation to previous research focused on (familial) social control and (individual) self-control with respect to psychosocial problems in adolescents. In addition, methodological considerations are discussed and the implications of the findings for clinical and community interventions to address problem behaviours, and for further study, are explored.

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It has been proposed that a sense of control (primary control) is critical to maintaining positive and stable subjective wellbeing (SWB). As people age and control capacity presumably declines (due to physical and cognitive deterioration and increased sociocultural challenges), it is argued that the influence of secondary perceived control (or acceptance) increases to help maintain normative levels of SWB. While previous studies have typically investigated the relationship between perceived control and global estimates of satisfaction (i.e., overall life satisfaction), the present study evaluated the link between perceived control and seven key domains of satisfaction in order to obtain a more comprehensive understanding of the control-satisfaction relationship. A community-based sample of 1,317 individuals (age range: 17–92 years) was utilised to examine potential age-related differences in perceived control (primary and secondary) and satisfaction. Findings revealed that primary and secondary perceived control both increased across age, with secondary perceived control increasing at a higher rate. Primary perceived control had predictive primacy for satisfaction over secondary perceived control (consistent with theory). A moderated mediation effect was also found, suggesting that, in later life, secondary perceived control influences primary perceived control and, in turn, influences satisfaction with various domains. Therefore, while primary control is important to wellbeing, it should be acknowledged that secondary perceived control may have unique significance to the wellbeing of older adults.

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The effects of operating conditions such as initiator and monomer concentration as well as reactor temperature of polymerization reactors are studied in this work. A recently developed hybrid model for polystyrene batch reactor is utilized in simulation study. The simulation results reveal the sensitivity of polymer properties and monomer conversion to variation of process operating conditions. In the second phase of this study, the optimization problem involving minimum time optimal temperature policy is considered for control study. An advanced neural network-based model predictive controller (NN-MPC) is designed and tested online. The experimental studies reveal that the developed controller is able to track the optimal setpoint with a minor oscillation and overshoot.

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Control of polymerization reactors is a challenging issue for researchers due to the complex reaction mechanisms. A lot of reactions occur simultaneously during polymerization. This leads to a polymerization system that is highly nonlinear in nature. In this work, a nonlinear advanced controller, named fuzzy logic controller (FLC), is developed for monitoring the batch free radical polymerization of polystyrene (PS) reactor. Temperature is used as an intermediate control variable to control polymer quality, because the products quality and quantity of polymer are directly depends on temperature. Different FLCs are developed through changing the number of fuzzy membership functions (MFs) for inputs and output. The final tuned FLC results are compared with the results of another advanced controller, named neural network based model predictive controller (NN-MPC). The simulation results reveal that the FLC performance is better than NN-MPC in terms of quantitative and qualitative performance criterion.

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Neurocomputational models of reaching indicate that efficient purposive correction of movement midflight (e.g., online control) depends on one's ability to generate and monitor an accurate internal (neural) movement representation. In the first study to test this empirically, the authors investigated the relationship between healthy young adults’ implicit motor imagery performance and their capacity to correct their reaching trajectory. As expected, after controlling for general reaching speed, hierarchical regression demonstrated that imagery ability was a significant predictor of hand correction speed; that is, faster and more accurate imagery performance associated with faster corrections to reaching following target displacement at movement onset. They argue that these findings provide preliminary support for the view that a link exists between an individual's ability to represent movement mentally and correct movement online efficiently.

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Locusts and grasshoppers cause considerable economic damage to agriculture worldwide. The Australian Plague Locust Commission uses multiple pesticides to control locusts in eastern Australia. Avian exposure to agricultural pesticides is of conservation concern, especially in the case of rare and threatened species. The aim of this study was to evaluate the probability of pesticide exposure of native avian species during operational locust control based on knowledge of species occurrence in areas and times of application. Using presence-absence data provided by the Birds Australia Atlas for 1998 to 2002, we developed a series of generalized linear models to predict avian occurrences on a monthly basis in 0.5 degrees grid cells for 280 species over 2 million km2 in eastern Australia. We constructed species-specific models relating occupancy patterns to survey date and location, rainfall, and derived habitat preference. Model complexity depended on the number of observations available. Model output was the probability of occurrence for each species at times and locations of past locust control operations within the 5-year study period. Given the high spatiotemporal variability of locust control events, the variability in predicted bird species presence was high, with 108 of the total 280 species being included at least once in the top 20 predicted species for individual space-time events. The models were evaluated using field surveys collected between 2000 and 2005, at sites with and without locust outbreaks. Model strength varied among species. Some species were under- or over-predicted as times and locations of interest typically did not correspond to those in the prediction data set and certain species were likely attracted to locusts as a food source. Field surveys demonstrated the utility of the spatially explicit species lists derived from the models but also identified the presence of a number of previously unanticipated species. These results also emphasize the need for special consideration of rare and threatened species that are poorly predicted by presence-absence models. This modeling exercise was a useful a priori approach in species risk assessments to identify species present at times and locations of locust control applications, and to discover gaps in our knowledge and need for further focused data collection.

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For children with Developmental Coordination Disorder (DCD), the real-time coupling between frontal executive function and online motor control has not been explored despite reported deficits in each domain. The aim of the present study was to investigate how children with DCD enlist online control under task constraints that compel the need for inhibitory control. A total of 129 school children were sampled from mainstream primary schools. Forty-two children who met research criteria for DCD were compared with 87 typically developing controls on a modified double-jump reaching task. Children within each skill group were divided into three age bands: younger (6-7 years), mid-aged (8-9), and older (10-12). Online control was compared between groups as a function of trial type (non-jump, jump, anti-jump). Overall, results showed that while movement times were similar between skill groups under simple task constraints (non-jump), on perturbation (or jump) trials the DCD group were significantly slower than controls and corrected trajectories later. Critically, the DCD group was further disadvantaged by anti-jump trials where inhibitory control was required; however, this effect reduced with age. While coupling online control and executive systems is not well developed in younger and mid-aged children, there is evidence of age-appropriate coupling in older children. Longitudinal data are needed to clarify this intriguing finding. The theoretical and applied implications of these results are discussed.

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Recent predictive processing accounts of perception and action point towards a key challenge for the nervous system in dynamically optimizing the balance between incoming sensory information and existing expectations regarding the state of the environment. Here, we report differences in the influence of the preceding sensory context on motor function, varying with respect to both clinical and subclinical features of autism spectrum disorder (ASD). Reach-to-grasp movements were recorded subsequent to an inactive period in which illusory ownership of a prosthetic limb was induced. We analysed the sub-components of reach trajectories derived using a minimum-jerk fitting procedure. Non-clinical adults low in autistic features showed disrupted movement execution following the illusion compared to a control condition. By contrast, individuals higher in autistic features (both those with ASD and non-clinical individuals high in autistic traits) showed reduced sensitivity to the presence of the illusion in their reaching movements while still exhibiting the typical perceptual effects of the illusion. Clinical individuals were distinct from non-clinical individuals scoring high in autistic features, however, in the early stages of movement. These results suggest that the influence of high-level representations of the environment differs between individuals, contributing to clinical and subclinical differences in motor performance that manifest in a contextual manner. As high-level representations of context help to explain fluctuations in sensory input over relatively longer time scales, more circumscribed sensitivity to prior or contextual information in autistic sensory processing could contribute more generally to reduced social comprehension, sensory impairments and a stronger desire for predictability and routine.

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In the past few years, cloud computing has emerged as one of the most influential paradigms in the IT industry. As promising as it is, this paradigm brings forth many new challenges for data security because users have to outsource sensitive data on untrusted cloud servers for sharing. In this paper, to guarantee the confidentiality and security of data sharing in cloud environment, we propose a Flexible and Efficient Access Control Scheme (FEACS) based on Attribute-Based Encryption, which is suitable for fine-grained access control. Compared with existing state-of-the-art schemes, FEACS is more practical by following functions. First of all, considering the factor that the user membership may change frequently in cloud environment, FEACS has the capability of coping with dynamic membership efficiently. Secondly, full logic expression is supported to make the access policy described accurately and efficiently. Besides, we prove in the standard model that FEACS is secure based on the Decisional Bilinear Diffie-Hellman assumption. To evaluate the practicality of FEACS, we provide a detailed theoretical performance analysis and a simulation comparison with existing schemes. Both the theoretical analysis and the experimental results prove that our scheme is efficient and effective for cloud environment.

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Introduction Surgical site infections (SSIs) often manifest after patients are discharged and are missed by hospital-based surveillance. Methods We conducted a case-reference study nested in a prospective cohort of patients from six surgical specialties in a teaching hospital. The factors related to SSI were compared for cases identified during the hospital stay and after discharge. Results Among 3,427 patients, 222 (6.4%) acquired an SSI. In 138 of these patients, the onset of the SSI occurred after discharge. Neurological surgery and the use of steroids were independently associated with a greater likelihood of SSI diagnosis during the hospital stay. Conclusions Our results support the idea of a specialty-based strategy for post-discharge SSI surveillance.