957 resultados para CURRENT SELF-OSCILLATION


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Aims: University student alcohol misuse is a considerable problem. Alcohol expectancy research has contributed significantly to our understanding of problem drinking in young adults. Most of this research has investigated positive expectancy alone. The current study utilized two measures of alcohol expectancy, the alcohol expectancy questionnaire (AEQ) and the drinking expectancy profile [consisting of the drinking expectancy questionnaire (DEQ) and the drinking refusal self-efficacy questionnaire] to predict severity of alcohol dependence, frequency of drinking, and the quantity of alcohol consumed per occasion. Methods: Measures of drinking behaviour and alcohol expectancy were completed by 174 undergraduate university students. Results: Positive alcohol expectancy factors accounted for significant variance in all three drinking indices, with the DEQ adding additional variance to AEQ scores on frequency and severity of alcohol dependence indices. Negative expectancy did not add incremental variance to the prediction of drinking behaviour in this sample. Drinking refusal self-efficacy and dependence beliefs added additional variance over positive and negative expectancies in the prediction of all three drinking parameters. Conclusions: Positive expectancy and drinking refusal self-efficacy were strongly related to university student drinking. The incorporation of expectancy as a means of informing prevention approaches in tertiary education shows promise.

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Conventional detection scheme for self-mixing sensors uses an integrated photodiode within the laser package to monitor the self mixing signal. This arrangement can be simplified by directly obtaining the self-mixing signals across the laser diode itself and omitting the photodiode. This work reports on a Vertical-Cavity Surface-Emitting Laser (VCSEL) based selfmixing sensor using the laser junction voltage to obtain the selfmixing signal. We show that the same information can be obtained with only minor changes to the extraction circuitry leading to potential cost saving with reductions in component costs and complexity and significant increase in bandwidth favoring high speed modulation. Experiments using both photo current and voltage detection were carried out and the results obtained show good agreement with the theory.

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A new control algorithm using parallel braking resistor (BR) and serial fault current limiter (FCL) for power system transient stability enhancement is presented in this paper. The proposed control algorithm can prevent transient instability during first swing by immediately taking away the transient energy gained in faulted period. It can also reduce generator oscillation time and efficiently make system back to the post-fault equilibrium. The algorithm is based on a new system energy function based method to choose optimal switching point. The parallel BR and serial FCL resistor can be switched at the calculated optimal point to get the best control result. This method allows optimum dissipation of the transient energy caused by disturbance so to make system back to equilibrium in minimum time. Case studies are given to verify the efficiency and effectiveness of this new control algorithm.

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The current experiment focuses on the roles of social identity and social comparison in perceptions of procedural justice. Participants are randomly allocated to conditions in a 2 (whether the participant has the opportunity to voice an opinion), X 2 (whether the comparison other has the opportunity to voice an opinion), X 2 (whether the comparison other is an ingroup or an outgroup member), between subjects design. Participants are then asked to report the extent to which they perceive the procedure they are involved in to be fair. It is predicted that participants will have a strong feeling of procedural unfairness when they are not given an opportunity by the leader to voice their opinion, but learn that their comparison other is given that opportunity. It is also predicted that the feeling of unfairness should be stronger when the comparison other is an outgroup rather than an ingroup member. Additionally, participants receiving a fair treatment may regard the procedure as fair when their outgoup comparison other receives an unfair treatment. Results support these predictions and reveal that how people make judgments of procedural justice through social comparison is qualified by the social identities of the parties involved.

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Normally ovulating women exhibit a decline in risk behaviours that may lead to sexual assault during the fertile phase of the menstrual cycle, whereas women using the Pill do not. The current study tests two explanatory models: the mood and fertility models. Self-reported risk and non-risk behaviours, mood, and risk perception in sexual assault and physical risk domains were assessed by testing fiftyone women at menstruation and during their fertile period. Based on the decline in risk behaviours shown in past research, the fertility model predicts that normally ovulating women will display greater risk perception during the fertile phase of their cycle. The mood model predicts that at menstruation, when negative mood is highest, risk perception will be increased and risk behaviours correspondingly reduced. Risk behaviours did not vary over the cycle or between groups. Overall, results support the mood model. Negative mood was greater at menstruation and positive mood during the fertile period for both groups, rational risk perception was correspondingly greater at menstruation. The fertility model was not supported as risk perception ratings did not vary in the expected direction and ratings were not specific to the sexual assault domain.

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The question of how to develop leaders so that they are more effective in a variety of situations, roles and levels has inspired a voluminous amount of research. While leader development programs such as executive coaching and 360-degree feedback have been widely practiced to meet this demand within organisations, the research in this area has only scratched the surface. Drawing from the past literature and leadership practices, the current research conceptualised self-regulation, as a metacompetency that would assist leaders to further develop the specific competencies needed to perform effectively in their leadership role, leading to an increased rating of leader effectiveness and to enhanced group performance. To test this conceptualisation, a longitudinal field experimental study was conducted across ten months with a pre- and two post-test intervention designs with a matched control group. This longitudinal field experimental compared the difference in leader and team performance after receiving self-regulation intervention that was delivered by an executive coach. Leaders in experimental group also received feedback reports from 360-degree feedback at each stage. Participants were 40 leaders, 155 followers and 8 supervisors. Leaders’ performance was measured using a multi-source perceptual measure of leader performance and objective measures of team financial and assessment performance. Analyses using repeated measure of ANCOVA on pre-test and two post-tests responses showed a significant difference between leader and team performance between experimental and control group. Furthermore, leader competencies mediated the relationship between self-regulation and performance. The implications of these findings for the theory and practice of leadership development training programs and the impact on organisational performance are discussed.

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Magnetic levitation bearings eliminate friction, wear and the need for lubrication and so have high speed capability and potential for vibration control. One noteworthy development in the realm of magnetic levitation is the self-bearing or bearingless motor - an electromagnetic machine that supports its own rotor by way of magnetic forces generated by windings on its stator. Accordingly, various winding schemes have been proposed to accomplish the task of force production. This thesis proposes a novel concept of winding based on a bridge connection for polyphase self-bearing rotating electrical machines with the following advantages: • the connection uses a single set of windings and thus power loss is relatively low when compared with self-bearing motors with conventional dual set of windings. • the motor and levitation controls are segregated such that only one motor inverter is required for the normal torque production and levitation forces are produced by using auxiliary power supplies of relatively low current and voltage rating. The usual way of controlling the motor is retained. • there are many variant winding schemes to meet special needs. • independent power supplies for levitation control offer redundancy for fault tolerance. This thesis dwells specifically on the conceptual design and implementation of the proposed single set of windings scheme. The new connection has been verified to exhibit characteristics of a self-bearing motor via coupled-field finite element analysis: results are crosschecked analytically. Power loss and other aspects such as cost, design implementation are compared to support the newly proposed connection as a potential alternative to present designs.

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The Report of the Robens Committee (1972), the Health and Safety at Work Act (1974) and the Safety Representatives and Safety Committees Regulations (1977) provide the framework within which this study of certain aspects of health and safety is carried out. The philosophy of self-regulation is considered and its development is set within an historical and an industrial relations perspective. The research uses a case study approach to examine the effectiveness of self-regulation in health and safety in a public sector organisation. Within this approach, methodological triangulation employs the techniques of interviews, questionnaires, observation and documentary analysis. The work is based in four departments of a Scottish Local Authority and particular attention is given to three of the main 'agents' of self-regulation - safety representatives, supervisors and safety committees and their interactions, strategies and effectiveness. A behavioural approach is taken in considering the attitudes, values, motives and interactions of safety representatives and management. Major internal and external factors, which interact and which influence the effectiveness of joint self-regulation of health and safety, are identified. It is emphasised that an organisation cannot be studied without consideration of the context within which it operates both locally and in the wider environment. One of these factors, organisational structure, is described as bureaucratic and the model of a Representative Bureaucracy described by Gouldner (1954) is compared with findings from the present study. An attempt is made to ascertain how closely the Local Authority fits Gouldner's model. This research contributes both to knowledge and to theory in the subject area by providing an in-depth study of self-regulation in a public sector organisation, which when compared with such studies as those of Beaumont (1980, 1981, 1982) highlights some of the differences between the public and private sectors. Both empirical data and hypothetical models are used to provide description and explanation of the operation of the health and safety system in the Local Authority. As data were collected during a dynamic period in economic, political and social terms, the research discusses some of the effects of the current economic recession upon safety organisation.

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This study seeks to describe current practice and opinion in schools for the maladjusted in England and Wales and to exarnlne how far this coincides with earlier descriptions. A review of the literature provides an account of this earlier work, and data accrued from questionnaires completed by 114 schools describe current practice and opinion. The study represents the most extensive empirical enquiry into the work of these schools since 1955 and provides a wide data basis for future research and assessment of progress and change. The data suggest that there is much communality of practice and opinion within the schools, with most schools emphasising their therapeutic rather than their educational purpose. The work is characterised by the wide use and perceived efficacy of warm, caring adult to child relationships, improvement of pupil self-image through success, and individual counselling and discussion, which permeate a structure of routine, discipline and educational concern. Specialised treatments are not used widely and involve only a minority of pupils. Practice tends to be in reference to conduct disordered pupils who are now perceived as the largest single disorder group within the schools, whereas previously neurotic disorders formed the largest single group. The majority of pupils are perceived as underachieving on entry and requiring remedial help: consequently the educational programme has a remedial bias. For staff, qualities of personality are considered to be more valuable than professional skills. The schools differ in the emphasis they allocate to one or more of four identified areas of treatment described as concern for pupils' needs; degree of pupil participation; theoretical orientation: and the use of external controls. There is a diminished reference to psychoanalytical theory and an increased reference to behaviourist theory relative to previous practice. Similarly, the use and perceived importance and effectiveness of pupil participation and unconditional affection has diminished.

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Relational demographers and dissimilarity researchers contend that group members who are dissimilar (vs. similar) to their peers in terms of a given diversity attribute (e.g. demographics, attitudes, values or traits) feel less attached to their work group, experience less satisfying and more conflicted relationships with their colleagues, and consequently are less effective. However, qualitative reviews suggest empirical findings tend to be weak and inconsistent (Chattopadhyay, Tluchowska and George, 2004; Riordan, 2000; Tsui and Gutek, 1999), and that it remains unclear when, how and to what extent such differences (i.e. relational diversity) affect group members social integration (i.e. attachment with their work group, satisfaction and conflicted relationships with their peers) and effectiveness (Riordan, 2000). This absence of meta-analytically derived effect size estimates and the lack of an integrative theoretical framework leave practitioners with inconclusive advice regarding whether the effects elicited by relational diversity are practically relevant, and if so how these should be managed. The current research develops an integrative theoretical framework, which it tests by using meta-analysis techniques and adding two further empirical studies to the literature. The first study reports a meta-analytic integration of the results of 129 tests of the relationship between relational diversity with social integration and individual effectiveness. Using meta-analytic and structural equation modelling techniques, it shows different effects of surface- and deep-level relational diversity on social integration Specifically, low levels of interdependence accentuated the negative effects of surface-level relational diversity on social integration, while high levels of interdependence accentuated the negative effects of deep-level relational diversity on social integration. The second study builds on a social self-regulation framework (Abrams, 1994) and suggests that under high levels of interdependence relational diversity is not one but two things: visibility and separation. Using ethnicity as a prominent example it was proposed that separation has a negative effect on group members effectiveness leading for those high in visibility and low in separation to overall positive additive effects, while to overall negative additive effects for those low in visibility and high in separation. These propositions were sustained in a sample of 621 business students working in 135 ethnically diverse work groups in a business simulation course over a period of 24 weeks. The third study suggests visibility has a positive effect on group members self-monitoring, while separation has a negative effect. The study proposed that high levels of visibility and low levels of separation lead to overall positive additive effects on self-monitoring but overall negative additive effects for those low in visibility and high in separation. Results from four waves of data on 261 business students working in 69 ethnically diverse work groups in a business simulation course held over a period of 24 weeks support these propositions.

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Self-criticism is strongly correlated with a range of psychopathologies, such as depression, eating disorders and anxiety. In contrast, self-reassurance is inversely associated with such psychopathologies. Despite the importance of self-judgements and evaluations, little is known about the neurophysiology of these internal processes. The current study therefore used a novel fMRI task to investigate the neuronal correlates of self-criticism and self-reassurance. Participants were presented statements describing two types of scenario, with the instruction to either imagine being self-critical or self-reassuring in that situation. One scenario type focused on a personal setback, mistake or failure, which would elicit negative emotions, whilst the second was of a matched neutral event. Self-criticism was associated with activity in lateral prefrontal cortex (PFC) regions and dorsal anterior cingulate (dAC), therefore linking self-critical thinking to error processing and resolution, and also behavioural inhibition. Self-reassurance was associated with left temporal pole and insula activation, suggesting that efforts to be self-reassuring engage similar regions to expressing compassion and empathy towards others. Additionally, we found a dorsal/ventral PFC divide between an individual's tendency to be self-critical or self-reassuring. Using multiple regression analyses, dorsolateral PFC activity was positively correlated with high levels of self-criticism (assessed via self-report measure), suggesting greater error processing and behavioural inhibition in such individuals. Ventrolateral PFC activity was positively correlated with high self-reassurance. Our findings may have implications for the neural basis of a range of mood disorders that are characterised by a preoccupation with personal mistakes and failures, and a self-critical response to such events.

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Background: Parkinson’s disease (PD) is an incurable neurological disease with approximately 0.3% prevalence. The hallmark symptom is gradual movement deterioration. Current scientific consensus about disease progression holds that symptoms will worsen smoothly over time unless treated. Accurate information about symptom dynamics is of critical importance to patients, caregivers, and the scientific community for the design of new treatments, clinical decision making, and individual disease management. Long-term studies characterize the typical time course of the disease as an early linear progression gradually reaching a plateau in later stages. However, symptom dynamics over durations of days to weeks remains unquantified. Currently, there is a scarcity of objective clinical information about symptom dynamics at intervals shorter than 3 months stretching over several years, but Internet-based patient self-report platforms may change this. Objective: To assess the clinical value of online self-reported PD symptom data recorded by users of the health-focused Internet social research platform PatientsLikeMe (PLM), in which patients quantify their symptoms on a regular basis on a subset of the Unified Parkinson’s Disease Ratings Scale (UPDRS). By analyzing this data, we aim for a scientific window on the nature of symptom dynamics for assessment intervals shorter than 3 months over durations of several years. Methods: Online self-reported data was validated against the gold standard Parkinson’s Disease Data and Organizing Center (PD-DOC) database, containing clinical symptom data at intervals greater than 3 months. The data were compared visually using quantile-quantile plots, and numerically using the Kolmogorov-Smirnov test. By using a simple piecewise linear trend estimation algorithm, the PLM data was smoothed to separate random fluctuations from continuous symptom dynamics. Subtracting the trends from the original data revealed random fluctuations in symptom severity. The average magnitude of fluctuations versus time since diagnosis was modeled by using a gamma generalized linear model. Results: Distributions of ages at diagnosis and UPDRS in the PLM and PD-DOC databases were broadly consistent. The PLM patients were systematically younger than the PD-DOC patients and showed increased symptom severity in the PD off state. The average fluctuation in symptoms (UPDRS Parts I and II) was 2.6 points at the time of diagnosis, rising to 5.9 points 16 years after diagnosis. This fluctuation exceeds the estimated minimal and moderate clinically important differences, respectively. Not all patients conformed to the current clinical picture of gradual, smooth changes: many patients had regimes where symptom severity varied in an unpredictable manner, or underwent large rapid changes in an otherwise more stable progression. Conclusions: This information about short-term PD symptom dynamics contributes new scientific understanding about the disease progression, currently very costly to obtain without self-administered Internet-based reporting. This understanding should have implications for the optimization of clinical trials into new treatments and for the choice of treatment decision timescales.

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Context/Motivation - Different modeling techniques have been used to model requirements and decision-making of self-adaptive systems (SASs). Specifically, goal models have been prolific in supporting decision-making depending on partial and total fulfilment of functional (goals) and non-functional requirements (softgoals). Different goalrealization strategies can have different effects on softgoals which are specified with weighted contribution-links. The final decision about what strategy to use is based, among other reasons, on a utility function that takes into account the weighted sum of the different effects on softgoals. Questions/Problems - One of the main challenges about decisionmaking in self-adaptive systems is to deal with uncertainty during runtime. New techniques are needed to systematically revise the current model when empirical evidence becomes available from the deployment. Principal ideas/results - In this paper we enrich the decision-making supported by goal models by using Dynamic Decision Networks (DDNs). Goal realization strategies and their impact on softgoals have a correspondence with decision alternatives and conditional probabilities and expected utilities in the DDNs respectively. Our novel approach allows the specification of preferences over the softgoals and supports reasoning about partial satisfaction of softgoals using probabilities. We report results of the application of the approach on two different cases. Our early results suggest the decision-making process of SASs can be improved by using DDNs. © 2013 Springer-Verlag.

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The behaviour of self adaptive systems can be emergent. The difficulty in predicting the system's behaviour means that there is scope for the system to surprise its customers and its developers. Because its behaviour is emergent, a self-adaptive system needs to garner confidence in its customers and it needs to resolve any surprise on the part of the developer during testing and mainteinance. We believe that these two functions can only be achieved if a self-adaptive system is also capable of self-explanation. We argue a self-adaptive system's behaviour needs to be explained in terms of satisfaction of its requirements. Since self-adaptive system requirements may themselves be emergent, a means needs to be found to explain the current behaviour of the system and the reasons that brought that behaviour about. We propose the use of goal-based models during runtime to offer self-explanation of how a system is meeting its requirements, and why the means of meeting these were chosen. We discuss the results of early experiments in self-explanation, and set out future work. © 2012 C.E.S.A.M.E.S.

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Background and Objective: Medication non-compliance is a considerable obstacle in achievinga therapeutic goal, whichcan result in poorerhealthcare outcomes, increased expenditure, wastage and potential for medication resistance. The UK Government’s Audit Commission’s publication ‘A Spoonful of Sugar’1 addresses these issues and promotes self-medication systems as a possible solution. The self-medication system within the Liver Transplant Unit (LTU) was implemented to induct patients onto new post- transplantation medication regimes ready for discharge. The system involves initial consultations with both the Liver Transplant Pharmacist and Trans- plant Co-ordinator, supported with additional advice as and when necessary. Design: Following ethical approval, evaluation of the self-medication sys- tem for liver transplant patients was conducted between January and March 2004 via two methods: audit and structured post-transplantation interview. The audit enabled any discrepancies between current Hospital guidelines and Liver Transplant Unit (LTU) practices to be highlighted. Patient interviews generated a retrospective insight into patient acceptance of the self-medication system. Setting: LTU, Queen Elizabeth Hospital, Birmingham, England. Main Outcome Measures: LTU compliance with Hospital self-medication guidelines and patient insight into self-medication system. Results: A total of seven patients were audited. Findings illustrated that self- medication by transplant patients is a complex process which was not fully addressed by current Hospital self-medication guidelines. Twenty-three patients were interviewed, showing an overwhelming positive attitude to- wards participating in their own care and a high level of understanding towards their individual medication regimes. Following a drugs counselling session, 100% of patients understood why they were taking their medica- tion, and their doses, 95% understood how to take their medication and 85% were aware of potential side effects. Conclusions: From this pilot evaluation it can be stated that the LTU self-medication system is appreciated by patients and assists them in fully understanding their medication regimes. There appear to be no major defects in the system. However areas such as communication barriers and on-going internet education were illustrated as areas for possible future investigation. References: 1. Audit Commission. A spoonful of sugar – medicines management in NHS hospitals. London: Audit Commission; 2001.