25 resultados para visual effects

em CentAUR: Central Archive University of Reading - UK


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The emergence and development of digital imaging technologies and their impact on mainstream filmmaking is perhaps the most familiar special effects narrative associated with the years 1981-1999. This is in part because some of the questions raised by the rise of the digital still concern us now, but also because key milestone films showcasing advancements in digital imaging technologies appear in this period, including Tron (1982) and its computer generated image elements, the digital morphing in The Abyss (1989) and Terminator 2: Judgment Day (1991), computer animation in Jurassic Park (1993) and Toy Story (1995), digital extras in Titanic (1997), and ‘bullet time’ in The Matrix (1999). As a result it is tempting to characterize 1981-1999 as a ‘transitional period’ in which digital imaging processes grow in prominence and technical sophistication, and what we might call ‘analogue’ special effects processes correspondingly become less common. But such a narrative risks eliding the other practices that also shape effects sequences in this period. Indeed, the 1980s and 1990s are striking for the diverse range of effects practices in evidence in both big budget films and lower budget productions, and for the extent to which analogue practices persist independently of or alongside digital effects work in a range of production and genre contexts. The chapter seeks to document and celebrate this diversity and plurality, this sustaining of earlier traditions of effects practice alongside newer processes, this experimentation with materials and technologies old and new in the service of aesthetic aspirations alongside budgetary and technical constraints. The common characterization of the period as a series of rapid transformations in production workflows, practices and technologies will be interrogated in relation to the persistence of certain key figures as Douglas Trumbull, John Dykstra, and James Cameron, but also through a consideration of the contexts for and influences on creative decision-making. Comparative analyses of the processes used to articulate bodies, space and scale in effects sequences drawn from different generic sites of special effects work, including science fiction, fantasy, and horror, will provide a further frame for the chapter’s mapping of the commonalities and specificities, continuities and variations in effects practices across the period. In the process, the chapter seeks to reclaim analogue processes’ contribution both to moments of explicit spectacle, and to diegetic verisimilitude, in the decades most often associated with the digital’s ‘arrival’.

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This paper presents a previously unpublished Attic lekythos and discusses visual ambiguity as an intentional drawing style used by a vase painter who conceptualised the many possible relationships between pot and user, object and subject. The Gela Painter endowed this hastily manufactured and decorated lekythos with visual effects that drew the viewer into an inherently ambivalent motif: a mounting Dionysos. This motif, like other Dionysian themes, had a vogue in late Archaic times but did not necessarily invoke chthonic associations. It had the potential to be consumed in diverse contexts, including religious festivals, by a wide range of audiences. Such images were not given to the viewer fully through visual perception but through interpretation.

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The Neolithic chambered tombs of Bohuslan on the west coast of Sweden were built out of locally occurring raw materials. These exhibit a wide variety of colours, textures and mineral inclusions, and all were used to contrive a series of striking visual effects. Certain of these would have been apparent to the casual observer but others would only have been apparent to someone inside the passage or the burial chamber. There is no evidence that the materials were organized according to a single scheme. Rather, they permitted a series of improvisations, so that no two monuments were exactly alike. The effects that they created are compared with those found in megalithic art where the design elements were painted or carved, but in Bohuslan all the designs were created using the natural properties of the rock.

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One goal in the development of distributed virtual environments (DVEs) is to create a system such that users are unaware of the distribution-the distribution should be transparent. The paper begins by discussing the general issues in DVEs that might make this possible, and a system that allows some level of distribution transparency is described. The system described suffers from effects of inconsistency, which in turn cause undesirable visual effects. The causal surface is introduced as a solution that removes these visual effects. The paper then introduces two determining factors of distribution transparency relating to user perception and performance. With regard to these factors, two hypotheses are stated relating to the causal surface. A user-trial on forty-five subjects is used to validate the hypotheses. A discussion of the results of the trial concludes that the causal surface solution does significantly improve the distribution transparency in a DVE.

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The authors assessed rats' encoding of the appearance or egocentric position of objects within visual scenes containing 3 objects (Experiment 1) or I object (Experiment 2A). Experiment 2B assessed encoding of the shape and fill pattern of single objects, and encoding of configurations (object + position, shape + fill). All were assessed by testing rats' ability to discriminate changes from familiar scenes (constant-negative paradigm). Perirhinal cortex lesions impaired encoding of objects and their shape; postrhinal cortex lesions impaired encoding of egocentric position, but the effect may have been partly due to entorhinal involvement. Neither lesioned group was impaired in detecting configural change. In Experiment 1, both lesion groups were impaired in detecting small changes in relative position of the 3 objects, suggesting that more sensitive tests might reveal configural encoding deficits.

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It is now well established that subthalamic nucleus high-frequency stimulation (STN HFS) alleviates motor problems in Parkinson's disease. However, its efficacy for cognitive function remains a matter of debate. The aim of this study was to assess the effects of STN HFS in rats performing a visual attentional task. Bilateral STN HFS was applied in intact and in bilaterally dopamine (DA)-depleted rats. In all animals, STN HFS had a transient debilitating effect on all the variables measured in the task. In DA-depleted rats, STN HFS did not alleviate the deficits induced by the DA lesion such as omissions and latency to make correct responses, but induced perseverative approaches to the food magazine, an indicator of enhanced motivation. In sham-operated controls, STN HFS significantly reduced accuracy and induced perseverative behaviour, mimicking partially the effects of bilateral STN lesions in the same task. These results are in line with the hypothesis that STN HFS only partially mimics inactivation of STN produced by lesioning and confirm the motivational exacerbation induced by STN inactivation.

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Two experiments investigated transfer effects in implicit memory and consumer choice, using a preference judgement task. Experiment 1 examined whether it is possible to obtain priming for unfamiliar food labels. Additionally, it investigated whether the experience of seeing a brand name with a particular product type would benefit subsequent processing of the brand name when linked with a different product type. Experiment 2 examined whether changes in modality between study and test would affect priming for unfamiliar brand names. Both questions are theoretically important, as well as pertaining to practical concerns in the consumer choice literature. Experiment 1 demonstrated significant priming for unfamiliar food labels, and established that priming was unaffected by changing the product type with which the brand name was associated. In Experiment 2, priming on both auditory and visual versions of the preference judgement task was reduced by changes in modality. The results and implications are discussed in relation to consumer choice and current theories of implicit memory.

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The use of semiochemicals for manipulation of the pollen beetle Meligethes aeneus (Fabricius) (Coleoptera: Nitidulidae) is being investigated for potential incorporation into a push-pull control strategy for this pest, which damages oilseed rape, Brassica napus L. (Brassicaceae), throughout Europe. The response of M. aeneus to non-host plant volatiles was investigated in laboratory assays to establish whether they have any effect on host plant location behaviour. Two approaches were used. First a novel, moving-air bioassay using air funnels was developed to compare the response of M. aeneus to several non-host plant essential oils. The beetles avoided the host plant flowers in the presence of non-host volatiles, suggesting that M. aeneus uses olfactory cues in host location and/or acceptance. The results were expressed as 'repellency values' in order to compare the effects of the different oils tested. Lavender (Lavendula angustifolia Miller) (Lamiaceae) essential oil gave the highest repellency value. In addition, a four-arm olfactometer was used to investigate olfactory responses, as this technique eliminated the influence of host plant visual and contact cues. The attraction to host plant volatiles was reduced by the addition of non-host plant volatiles, but in addition to masking the host plant volatiles, the non-host volatiles were avoided when these were presented alone. This is encouraging for the potential use of non-host plants within a push-pull strategy to reduce the pest colonisation of crops. Further testing in more realistic semi-field and field trials is underway.

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Purpose. Some children with visual stress and/or headaches have fewer symptoms when wearing colored lenses. Although subjective reports of improved perception exist, few objective correlates of these effects have been established. Methods. In a pilot study, 10 children who wore Intuitive Colorimeter lenses, and claimed benefit, and two asymptomatic children were tested. Steady-state potentials were measured in response to low contrast patterns modulating at a frequency of 12 Hz. Four viewing conditions were compared: 1) no lens; 2) Colorimeter lens; 3) lens of complementary color; and 4) spectrally neutral lens with similar photopic transmission. Results. The asymptomatic children showed little or no difference between the lens and no lens conditions. When all the symptomatic children were tested together, a similar result was found. However, when the symptomatic children were divided into two groups depending on their symptoms, an interaction emerged. Children with visual stress but no headaches showed the largest amplitude visual evoked potential response in the no lens condition, whereas those children whose symptoms included severe headaches or migraine showed the largest amplitude visual evoked potential response when wearing their prescribed lens. Conclusions. The results suggest that it is possible to measure objective correlates of the beneficial subjective perceptual effects of colored lenses, at least in some children who have a history of migraine or severe headaches.

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This study explores the effects of exposure to pictures of fruits and vegetables on young children's willingness to taste the foods. The parents of 20 toddlers aged 21-24 months were asked to read a picture book about four foods with their child every day for two weeks. in a subsequent 'taste test' children displayed a neophobic pattern of behaviour towards foods to which they had not been exposed, but not towards exposed foods. Furthermore, while exposure served to decrease children's willingness to taste familiar vegetables, it increased their willingness to taste unfamiliar fruits. (C) 2009 Elsevier Ltd. All rights reserved.

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In immediate recall tasks, visual recency is substantially enhanced when output interference is low (Cowan, Saults, Elliott, & Moreno, 2002; Craik, 1969) whereas auditory recency remains high even under conditions of high output interference. Ibis auditory advantage has been interpreted in terms of auditory resistance to output interference (e.g., Neath & Surprenant, 2003). In this study the auditory-visual difference at low output interference re-emerged when ceiling effects were accounted for, but only with spoken output. With written responding the auditory advantage remained significantly larger with high than with low output interference. These new data suggest that both superior auditory encoding and modality-specific output interference contribute to the classic auditory-visual modality effect.

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Two experiments examine the effects of extraneous speech and nonspeech noise on a visual short-term memory task administered to younger and older adults. Experiment 1 confirms an earlier report that playing task-irrelevant speech is no more distracting for older adults than for younger adults (Rouleau T Belleville, 1996), indicating that "irrelevant sound effects" in short-term memory operate in a different manner to recalling targets in the presence of competing speech (Tun, O'Kane, T Wingfield, 2002). Experiment 2 extends this result to nonspeech noise and demonstrates that the result cannot be ascribed to hearing difficulties amongst the older age group, although the data also show that older adults rated the noise as less annoying and uncomfortable than younger adults. Implications for theories of the irrelevant sound effect, and for cognitive ageing, are discussed.

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There are still major challenges in the area of automatic indexing and retrieval of digital data. The main problem arises from the ever increasing mass of digital media and the lack of efficient methods for indexing and retrieval of such data based on the semantic content rather than keywords. To enable intelligent web interactions or even web filtering, we need to be capable of interpreting the information base in an intelligent manner. Research has been ongoing for a few years in the field of ontological engineering with the aim of using ontologies to add knowledge to information. In this paper we describe the architecture of a system designed to automatically and intelligently index huge repositories of special effects video clips, based on their semantic content, using a network of scalable ontologies to enable intelligent retrieval.

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Computer vision applications generally split their problem into multiple simpler tasks. Likewise research often combines algorithms into systems for evaluation purposes. Frameworks for modular vision provide interfaces and mechanisms for algorithm combination and network transparency. However, these don’t provide interfaces efficiently utilising the slow memory in modern PCs. We investigate quantitatively how system performance varies with different patterns of memory usage by the framework for an example vision system.

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A common procedure for studying the effects on cognition of repetitive transcranial magnetic stimulation (rTMS) is to deliver rTMS concurrent with task performance, and to compare task performance on these trials versus on trials without rTMS. Recent evidence that TMS can have effects on neural activity that persist longer than the experimental session itself, however, raise questions about the assumption of the transient nature of rTMS that underlies many concurrent (or "online") rTMS designs. To our knowledge, there have been no studies in the cognitive domain examining whether the application of brief trains of rTMS during specific epochs of a complex task may have effects that spill over into subsequent task epochs, and perhaps into subsequent trials. We looked for possible immediate spill-over and longer-term cumulative effects of rTMS in data from two studies of visual short-term delayed recognition. In 54 subjects, 10-Hz rTMS trains were applied to five different brain regions during the 3-s delay period of a spatial task, and in a second group of 15 subjects, electroencephalography (EEG) was recorded while 10-Hz rTMS was applied to two brain areas during the 3-s delay period of both spatial and object tasks. No evidence for immediate effects was found in the comparison of the memory probe-evoked response on trials that were vs. were not preceded by delay-period rTMS. No evidence for cumulative effects was found in analyses of behavioral performance, and of EEG signal, as a function of task block. The implications of these findings, and their relation to the broader literature on acute vs. long-lasting effects of rTMS, are considered.