997 resultados para flux behaviour
Resumo:
Over-involved parenting is commonly hypothesized to be it risk factor for the development of anxiety disorders in childhood. This parenting style may result from parental attempts to prevent child distress based on expectations that the child will be unable to cope in a challenging situation. Naturalistic studies are limited in their ability to disentangle the overlapping contribution of child and parent factors in driving parental behaviours. To overcome this difficulty, an experimental study was conducted in which parental expectations of child distress were manipulated and the effects on parent behaviour and child mood were assessed. Fifty-two children (aged 7 - 11 years) and their primary caregiver participated. Parents were allocated to either a "positive" or a "negative" expectation group. Observations were made of the children and their parents interacting whilst completing a difficult anagram task. Parents given negative expectations of their child's response displayed higher levels of involvement. No differences were found on indices of child mood and behaviour and possible explanations for this are considered. The findings are consistent with suggestions that increased parental involvement may be a "natural" reaction to enhanced perceptions of child vulnerability and an attempt to avoid child distress.
Resumo:
The eating disorders provide one of the strongest indications for cognitive behaviour therapy (CBT). This bold claim arises from two sources: first, the fact that eating disorders are essentially cognitive disorders and second, the demonstrated effectiveness of CBT in the treatment of bulimia nervosa, which has led to the widespread acceptance that CBT is the treatment of choice. In this paper the cognitive behavioural approach to the understanding and treatment of eating disorders will be described. A brief summary of the evidence for this account and of the data supporting the efficacy and effectiveness of this form of treatment will be provided. Challenges for the future development and dissemination of the treatment will be identified.
Resumo:
This paper proposes a novel method of authentication of users in secure buildings. The main objective is to investigate whether user actions in the built environment can produce consistent behavioural signatures upon which a building intrusion detection system could be based. In the process three behavioural expressions were discovered: time-invariant, co-dependent and idiosyncratic.
Resumo:
Numerous techniques exist which can be used for the task of behavioural analysis and recognition. Common amongst these are Bayesian networks and Hidden Markov Models. Although these techniques are extremely powerful and well developed, both have important limitations. By fusing these techniques together to form Bayes-Markov chains, the advantages of both techniques can be preserved, while reducing their limitations. The Bayes-Markov technique forms the basis of a common, flexible framework for supplementing Markov chains with additional features. This results in improved user output, and aids in the rapid development of flexible and efficient behaviour recognition systems.
Resumo:
Multiple cooperating robot systems may be required to take up a closely coupled configuration in order to perform a task. An example is extended baseline stereo (EBS), requiring that two robots must establish and maintain for a certain period of time a constrained kinematic relationship to each other. In this paper we report on the development of a networked robotics framework for modular, distributed robot systems that supports the creation of such configurations. The framework incorporates a query mechanism to locate modules distributed across the two robot systems. The work presented in this paper introduces special mechanisms to model the kinematic constraint and its instantiation. The EBS configuration is used as a case study and experimental implementation to demonstrate the approach.
Resumo:
The Web's link structure (termed the Web Graph) is a richly connected set of Web pages. Current applications use this graph for indexing and information retrieval purposes. In contrast the relationship between Web Graph and application is reversed by letting the structure of the Web Graph influence the behaviour of an application. Presents a novel Web crawling agent, AlienBot, the output of which is orthogonally coupled to the enemy generation strategy of a computer game. The Web Graph guides AlienBot, causing it to generate a stochastic process. Shows the effectiveness of such unorthodox coupling to both the playability of the game and the heuristics of the Web crawler. In addition, presents the results of the sample of Web pages collected by the crawling process. In particular, shows: how AlienBot was able to identify the power law inherent in the link structure of the Web; that 61.74 per cent of Web pages use some form of scripting technology; that the size of the Web can be estimated at just over 5.2 billion pages; and that less than 7 per cent of Web pages fully comply with some variant of (X)HTML.
Resumo:
The high variability of the intensity of suprathermal electron flux in the solar wind is usually ascribed to the high variability of sources on the Sun. Here we demonstrate that a substantial amount of the variability arises from peaks in stream interaction regions, where fast wind runs into slow wind and creates a pressure ridge at the interface. Superposed epoch analysis centered on stream interfaces in 26 interaction regions previously identified in Wind data reveal a twofold increase in 250 eV flux (integrated over pitch angle). Whether the peaks result from the compression there or are solar signatures of the coronal hole boundary, to which interfaces may map, is an open question. Suggestive of the latter, some cases show a displacement between the electron and magnetic field peaks at the interface. Since solar information is transmitted to 1 AU much more quickly by suprathermal electrons compared to convected plasma signatures, the displacement may imply a shift in the coronal hole boundary through transport of open magnetic flux via interchange reconnection. If so, however, the fact that displacements occur in both directions and that the electron and field peaks in the superposed epoch analysis are nearly coincident indicate that any systematic transport expected from differential solar rotation is overwhelmed by a random pattern, possibly owing to transport across a ragged coronal hole boundary.
Resumo:
Most of the dissolved organic carbon (DOC) exported from catchments is transported during storm events. Accurate assessments of DOC fluxes are essential to understand long-term trends in the transport of DOC from terrestrial to aquatic systems, and also the loss of carbon from peatlands to determine changes in the source/sink status of peatland carbon stores. However, many long-term monitoring programmes collect water samples at a frequency (e.g. weekly/monthly) less than the time period of a typical storm event (typically <1–2 days). As widespread observations in catchments dominated by organo-mineral soils have shown that both concentration and flux of DOC increases during storm events, lower frequency monitoring could result in substantial underestimation of DOC flux as the most dynamic periods of transport are missed. However, our intensive monitoring study in a UK upland peatland catchment showed a contrasting response to these previous studies. Our results showed that (i) DOC concentrations decreased during autumn storm events and showed a poor relationship with flow during other seasons; and that (ii) this decrease in concentrations during autumn storms caused DOC flux estimates based on weekly monitoring data to be over-estimated, rather than under-estimated, because of over rather than under estimation of the flow-weighted mean concentration used in flux calculations. However, as DOC flux is ultimately controlled by discharge volume, and therefore rainfall, and the magnitude of change in discharge was greater than the magnitude of decline in concentrations, DOC flux increased during individual storm events. The implications for long-term DOC trends are therefore contradictory, as increased rainfall could increase flux but cause an overall decrease in DOC concentrations from peatland streams. Care needs to be taken when interpreting long-term trends in DOC flux rather than concentration; as flux is calculated from discharge estimates, and discharge is controlled by rainfall, DOC flux and rainfall/discharge will always be well correlated.
Resumo:
A flux-difference splitting method is presented for the inviscid terms of the compressible flow equations for chemical non-equilibrium gases