588 resultados para nonlinear electrical behaviour


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The goal of this study was to utilise an objective measurement tool, via an on-board Diagnostic tool (OBDII), to explore the effectiveness of a behaviour modification intervention designed to reduce over-speed violations in a group of work-related drivers. It was predicted that over-speed violations would be decreased following participation in a behaviour modification intervention where drivers received weekly feedback on their speeding performance and goal setting exercises. The final analysis included the on-road behaviour of 16 drivers, all of whom completed each stage of the intervention program. As predicted, over-speed violations significantly decreased from pre-test to post-test, after controlling for kilometres driven. These findings offer practical guidance for industry in developing interventions designed to improve work-related driving behaviour.

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The study examines the illness behaviour of patients with Chronic Fatigue Syndrome (CFS). The Illness Behaviour Questionnaire (IBQ) the twenty-eight version of the General Health Questionnaire (GBQ-28), and the Beck Depression Inventory (BDI) were administered to forty patients with a diagnosis of CFS. The results revealed that CFS patients in comparison with general practice patients, scored significantly higher on the IBQ sub-scales of General Hypochonriasis, t(188) = 5.2, p < 0.001 and Disease Conviction, t(188) = 13.28, p < 0.001 but lower on the Psychological/Somatic sub-scale, t(188) = -5.88, p < 0.001. The CFS and psychiatric patients did not differ significantly on the general hypochondriasis sub-scale. Results of the GHQ-28 revealed 66.7% of the CFS patients scored above the cut-off for psychiatric morbidity. In comparison to a previous study of CFS patients [1], the current findings indicate a significantly higher score on general hypochondriasis. The implications of these findings are discussed.

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The aim of this study was to validate the Children’s Eating Behaviour Questionnaire (CEBQ) in three ethnically and culturally diverse samples of mothers in Australia. Confirmatory factor analysis utilising structural equation modelling examined whether the established 8-factor model of the CEBQ was supported in our three populations: (i) a community sample of first-time mothers allocated to the control group of the NOURISH trial (mean child age = 24 months [SD = 1]; N = 244); (ii) a sample of immigrant Indian mothers of children aged 1–5 years (mean age = 34 months [SD = 14]; N = 203), and (iii) a sample of immigrant Chinese mothers of children aged 1–4 years (mean age = 36 months [SD = 14]; N = 216). The original 8-factor model provided an acceptable fit to the data in the NOURISH sample with minor post hoc re-specifications (two error covariances on Satiety Responsiveness and an item-factor covariance to account for a cross-loading of an item (Fussiness) on Satiety Responsiveness). The re-specified model showed reasonable fit in both the Indian and Chinese samples. Cronbach’s α estimates ranged from .73 to .91 in the Australian sample and .61–.88 in the immigrant samples. This study supports the appropriateness of the CEBQ in the multicultural Australian context.

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We extended the previous work of Moss, O’Connor and White, to include a measure of group norms within the theory of planned behaviour (TPB), to examine the influences on students’ decisions to use lecture podcasts as part of their learning. Participants (N = 90) completed the extended TPB predictors before semester began (Time 1) and mid-semester (Time 2) and reported on their podcast use at mid-semester (Time 2) and end of semester (Time 3). We found that attitudes and perceived social pressures were important in informing intentions at both time points. At Time 1, perceptions of control over performing the behaviour and, at Time 2, perceptions of whether podcast use was normative among fellow students (group norms) also predicted intended podcast use. Intentions to use podcasting predicted self-reported use at both Time 2 and Time 3. These results provide important applied information for educators to encourage student use of novel on-line educational tools.

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Business processes depend on human resources and managers must regularly evaluate the performance of their employees based on a number of measures, some of which are subjective in nature. As modern organisations use information systems to automate their business processes and record information about processes’ executions in event logs, it now becomes possible to get objective information about resource behaviours by analysing data recorded in event logs. We present an extensible framework for extracting knowledge from event logs about the behaviour of a human resource and for analysing the dynamics of this behaviour over time. The framework is fully automated and implements a predefined set of behavioural indicators for human resources. It also provides a means for organisations to define their own behavioural indicators, using the conventional Structured Query Language, and a means to analyse the dynamics of these indicators. The framework's applicability is demonstrated using an event log from a German bank.

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A victim of phishing emails could be subjected to money loss and identity theft. This paper investigates the different types of phishing email victims, with the goal of increasing such victims' defences. To obtain this kind of information, an experiment which involves sending a phishing email to participants is conducted. Quantitative and qualitative methods are also used to collect users' information. A model for detecting deception has been employed to understand victims' behaviour. This paper reports the qualitative results. The findings suggest that victims of phishing emails do not always exhibit the same vulnerability. The cause of being a victim is a result of three weaknesses in the detection process: (1) lack of knowledge; (2) weak confirmation channel, and; (3) victims' high propensity towards risk-taking. Therefore, it is suggested that users be provided with suitable confirmation channels and be more risk averse in their behaviour so that they would not fall victim to phishing emails.

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Despite statistics indicating that the African region has the highest road traffic fatality rate globally, there is limited scientific literature identifying the determinants of driving behaviour. In this study, we explore differences in self-reported driving behaviour across age groups and years of education in a population of 213 drivers from Addis Ababa, Ethiopia. We hypothesize that younger, less educated drivers will report engaging in more unsafe driving behaviours compared to older, more educated drivers. Contrary to expectations, we found the opposite effect, whereby older, more educated drivers reported engaging in more unsafe driving behaviours than younger, less educated drivers. We explain these findings by describing key characteristics of the sample and cultural ideologies of the region. The findings of this study offer some practical guidance for intervention to address the burden of road traffic injury and death in the African region.

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In this paper an approach is presented for identification of a reduced model for coherent areas in power systems using phasor measurement units to represent the inter-area oscillations of the system. The generators which are coherent in a wide range of operating conditions form the areas in power systems and the reduced model is obtained by representing each area by an equivalent machine. The reduced nonlinear model is then identified based on the data obtained from measurement units. The simulation is performed on three test systems and the obtained results show high accuracy of identification process.

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This paper presents a new hybrid evolutionary algorithm based on Particle Swarm Optimization (PSO) and Ant Colony Optimization (ACO) for daily Volt/Var control in distribution system including Distributed Generators (DGs). Due to the small X/R ratio and radial configuration of distribution systems, DGs have much impact on this problem. Since DGs are independent power producers or private ownership, a price based methodology is proposed as a proper signal to encourage owners of DGs in active power generation. Generally, the daily Volt/Var control is a nonlinear optimization problem. Therefore, an efficient hybrid evolutionary method based on Particle Swarm Optimization and Ant Colony Optimization (ACO), called HPSO, is proposed to determine the active power values of DGs, reactive power values of capacitors and tap positions of transformers for the next day. The feasibility of the proposed algorithm is demonstrated and compared with methods based on the original PSO, ACO and GA algorithms on IEEE 34-bus distribution feeder.

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The nonlinear problem of steady free-surface flow past a submerged source is considered as a case study for three-dimensional ship wave problems. Of particular interest is the distinctive wedge-shaped wave pattern that forms on the surface of the fluid. By reformulating the governing equations with a standard boundary-integral method, we derive a system of nonlinear algebraic equations that enforce a singular integro-differential equation at each midpoint on a two-dimensional mesh. Our contribution is to solve the system of equations with a Jacobian-free Newton-Krylov method together with a banded preconditioner that is carefully constructed with entries taken from the Jacobian of the linearised problem. Further, we are able to utilise graphics processing unit acceleration to significantly increase the grid refinement and decrease the run-time of our solutions in comparison to schemes that are presently employed in the literature. Our approach provides opportunities to explore the nonlinear features of three-dimensional ship wave patterns, such as the shape of steep waves close to their limiting configuration, in a manner that has been possible in the two-dimensional analogue for some time.

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The safety of passengers is a major concern to airports. In the event of crises, having an effective and efficient evacuation process in place can significantly aid in enhancing passenger safety. Hence, it is necessary for airport operators to have an in-depth understanding of the evacuation process of their airport terminal. Although evacuation models have been used in studying pedestrian behaviour for decades, little research has been done in considering the evacuees’ group dynamics and the complexity of the environment. In this paper, an agent-based model is presented to simulate passenger evacuation process. Different exits were allocated to passengers based on their location and security level. The simulation results show that the evacuation time can be influenced by passenger group dynamics. This model also provides a convenient way to design airport evacuation strategy and examine its efficiency. The model was created using AnyLogic software and its parameters were initialised using recent research data published in the literature.

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We report a new approach that uses the single beam Z-scan technique, to discriminate between excited state absorption (ESA) and two and three photon nonlinear absorption. By measuring the apparent delay or advance of the pulse in reaching the detector, the nonlinear absorption can be unambiguously identified as either instantaneous or transient. The simple method does not require a large range of input fluences or sophisticated pulse-probe experimental apparatus. The technique is easily extended to any absorption process dependent on pulse width and to nonlinear refraction measurements. We demonstrate in particular, that the large nonlinear absorption in ZnO nanocones when exposed to nanosecond 532 nm pulses, is due mostly to ESA, not pure two-photon absorption.

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The past decade has seen an increase in the number of significant natural disasters that have caused considerable loss of life as well as damage to all property markets in the affected areas. In many cases, these natural disasters have not only caused significant property damage, but in numerous cases, have resulted in the total destruction of the property in the location. With these disasters attracting considerable media attention, the public are more aware of where these affected property markets are, as well as the overall damage to properties that have been damaged or destroyed. This heightened level of awareness has to have an impact on the participants in the property market, whether a developer, vendor seller or investor. To assess this issue, a residential property market that has been affected by a significant natural disaster over the past 2 years has been analysed to determine the overall impact of the disaster on buyer, renter and vendor behaviour, as well as prices in these residential markets. This paper is based on data from the Brisbane flood in January 2011. This natural disaster resulted in loss of life and partial and total devastation of considerable residential property sectors. Data for the research have been based on the residential sales and rental listings for each week of the study period to determine the level of activity in the specific property sectors, and these are also compared to the median house prices for the various suburbs for the same period based on suburbs being either flood affected or flood free. As there are 48 suburbs included in the study, it has been possible to group these suburbs on a socio-economic basis to determine possible differences due to location and value. Data were accessed from realestate.com.au, a free real estate site that provides details of current rental and sales listings on a suburb basis, RP Data a commercial property sales database and the Australian Bureau of Statistics. The paper found that sales listings fell immediately after the flood in the affected areas, but there was no corresponding fall or increase in sales listings in the flood-free suburbs. There was a significant decrease in the number of rental listings follow the flood as affected parties sought alternate accommodation. The greatest fall in rental listings was in areas close to the flood-affected suburbs indicating the desire to be close to the flooded property during the repair period.

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The Brain Research Institute (BRI) uses various types of indirect measurements, including EEG and fMRI, to understand and assess brain activity and function. As well as the recovery of generic information about brain function, research also focuses on the utilisation of such data and understanding to study the initiation, dynamics, spread and suppression of epileptic seizures. To assist with the future focussing of this aspect of their research, the BRI asked the MISG 2010 participants to examine how the available EEG and fMRI data and current knowledge about epilepsy should be analysed and interpreted to yield an enhanced understanding about brain activity occurring before, at commencement of, during, and after a seizure. Though the deliberations of the study group were wide ranging in terms of the related matters considered and discussed, considerable progress was made with the following three aspects. (1) The science behind brain activity investigations depends crucially on the quality of the analysis and interpretation of, as well as the recovery of information from, EEG and fMRI measurements. A number of specific methodologies were discussed and formalised, including independent component analysis, principal component analysis, profile monitoring and change point analysis (hidden Markov modelling, time series analysis, discontinuity identification). (2) Even though EEG measurements accurately and very sensitively record the onset of an epileptic event or seizure, they are, from the perspective of understanding the internal initiation and localisation, of limited utility. They only record neuronal activity in the cortical (surface layer) neurons of the brain, which is a direct reflection of the type of electrical activity they have been designed to record. Because fMRI records, through the monitoring of blood flow activity, the location of localised brain activity within the brain, the possibility of combining fMRI measurements with EEG, as a joint inversion activity, was discussed and examined in detail. (3) A major goal for the BRI is to improve understanding about ``when'' (at what time) an epileptic seizure actually commenced before it is identified on an eeg recording, ``where'' the source of this initiation is located in the brain, and ``what'' is the initiator. Because of the general agreement in the literature that, in one way or another, epileptic events and seizures represent abnormal synchronisations of localised and/or global brain activity the modelling of synchronisations was examined in some detail. References C. M. Michel, G. Thut, S. Morand, A. Khateb, A. J. Pegna, R. Grave de Peralta, S. Gonzalez, M. Seeck and T. Landis, Electric source imaging of human brain functions, Brain Res. 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Background Improvised explosive devices have become the characteristic weapon of conflicts in Iraq and Afghanistan. While little can be done to mitigate against the effects of blast in free-field explosions, scaled blast simulations have shown that the combat boot can attenuate the effects on the vehicle occupants of anti-vehicular mine blasts. Although the combat boot offers some protection to the lower limb, its behaviour at the energies seen in anti-vehicular mine blast has not been documented previously. Methods The sole of eight same-size combat boots from two brands currently used by UK troops deployed to Iraq and Afghanistan were impacted at energies of up to 518 J, using a spring-assisted drop rig. Results The results showed that the Meindl Desert Fox combat boot consistently experienced a lower peak force at lower impact energies and a longer time-to-peak force at higher impact energies when compared with the Lowa Desert Fox combat boot. Discussion This reduction in the peak force and extended rise time, resulting in a lower energy transfer rate, is a potentially positive mitigating effect in terms of the trauma experienced by the lower limb. Conclusion Currently, combat boots are tested under impact at the energies seen during heel strike in running. Through the identification of significantly different behaviours at high loading, this study has shown that there is rationale in adding the performance of combat boots under impact at energies above those set out in international standards to the list of criteria for the selection of a combat boot.