1,191 research outputs found
Few-Shot Single-View 3-D Object Reconstruction with Compositional Priors
The impressive performance of deep convolutional neural networks in
single-view 3D reconstruction suggests that these models perform non-trivial
reasoning about the 3D structure of the output space. However, recent work has
challenged this belief, showing that complex encoder-decoder architectures
perform similarly to nearest-neighbor baselines or simple linear decoder models
that exploit large amounts of per category data in standard benchmarks. On the
other hand settings where 3D shape must be inferred for new categories with few
examples are more natural and require models that generalize about shapes. In
this work we demonstrate experimentally that naive baselines do not apply when
the goal is to learn to reconstruct novel objects using very few examples, and
that in a \emph{few-shot} learning setting, the network must learn concepts
that can be applied to new categories, avoiding rote memorization. To address
deficiencies in existing approaches to this problem, we propose three
approaches that efficiently integrate a class prior into a 3D reconstruction
model, allowing to account for intra-class variability and imposing an implicit
compositional structure that the model should learn. Experiments on the popular
ShapeNet database demonstrate that our method significantly outperform existing
baselines on this task in the few-shot setting
A progressive refinement approach for the visualisation of implicit surfaces
Visualising implicit surfaces with the ray casting method is a slow procedure. The design cycle of a new implicit surface is, therefore, fraught with long latency times as a user must wait for the surface to be rendered before being able to decide what changes should be introduced in the next iteration. In this paper, we present an attempt at reducing the design cycle of an implicit surface modeler by introducing a progressive refinement rendering approach to the visualisation of implicit surfaces. This progressive refinement renderer provides a quick previewing facility. It first displays a low quality estimate of what the final rendering is going to be and, as the computation progresses, increases the quality of this estimate at a steady rate. The progressive refinement algorithm is based on the adaptive subdivision of the viewing frustrum into smaller cells. An estimate for the variation of the implicit function inside each cell is obtained with an affine arithmetic range estimation technique. Overall, we show that our progressive refinement approach not only provides the user with visual feedback as the rendering advances but is also capable of completing the image faster than a conventional implicit surface rendering algorithm based on ray casting
Culture and personality revisited: Behavioral profiles and withinâperson stability in interdependent (vs. independent) social orientation and holistic (vs. analytic) cognitive style
ObjectiveWe test the proposition that both social orientation and cognitive style are constructs consisting of loosely related attributes. Thus, measures of each construct should weakly correlate among themselves, forming intraindividually stable profiles across measures over time.MethodStudy 1 tested diverse samples of Americans (NÂ =Â 233) and Japanese (NÂ =Â 433) with a wide range of measures of social orientation and cognitive style to explore correlations among these measures in a crossâcultural context, using demographically heterogeneous samples. Study 2 recruited a new sample of 485 Americans and Canadians and examined their profiles on measures of social orientation and cognitive style twice, one month apart, to assess the stability of individual profiles using these variables.ResultsDespite finding typical crossâcultural differences, Study 1 demonstrated negligible correlations both among measures of social orientation and among measures of cognitive style. Study 2 demonstrated stable intraindividual behavioral profiles across measures capturing idiosyncratic patters of social orientation and cognitive style, despite negligible correlations among the same measures.ConclusionThe results provide support for the behavioral profile approach to conceptualizing social orientation and cognitive style, highlighting the need to assess intraindividual stability of psychological constructs in crossâcultural research.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/162694/2/jopy12536_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162694/1/jopy12536.pd
Activation in a Frontoparietal Cortical Network Underlies Individual Differences in the Performance of an Embedded Figures Task
The Embedded Figures Test (EFT) requires observers to search for a simple geometric shape hidden inside a more complex figure. Surprisingly, performance in the EFT is negatively correlated with susceptibility to illusions of spatial orientation, such as the Roelofs effect. Using fMRI, we previously demonstrated that regions in parietal cortex are involved in the contextual processing associated with the Roelofs task. In the present study, we found that similar parietal regions (superior parietal cortex and precuneus) were more active during the EFT than during a simple matching task. Importantly, these parietal activations overlapped with regions found to be involved during contextual processing in the Roelofs illusion. Additional parietal and frontal areas, in the right hemisphere, showed strong correlations between brain activity and behavioral performance during the search task. We propose that the posterior parietal regions are necessary for processing contextual information across many different, but related visuospatial tasks, with additional parietal and frontal regions serving to coordinate this processing in participants proficient in the task
Global and local perceptual style, field-independence, and central coherence: An attempt at concept validation.
Historically, the concepts of field-independence, closure flexibility, and weak
central coherence have been used to denote a locally, rather globally, dominated
perceptual style. To date, there has been little attempt to clarify the
relationship between these constructs, or to examine the convergent validity of
the various tasks purported to measure them. To address this, we administered 14
tasks that have been used to study visual perceptual styles to a group of 90
neuro-typical adults. The data were subjected to exploratory factor analysis. We
found evidence for the existence of a narrowly defined weak central coherence
(field-independence) factor that received loadings from only a few of the tasks
used to operationalise this concept. This factor can most aptly be described as
representing the ability to dis-embed a simple stimulus from a more complex
array. The results suggest that future studies of perceptual styles should
include tasks whose theoretical validity is empirically verified, as such
validity cannot be established merely on the basis of a priori task analysis.
Moreover, the use of multiple indices is required to capture the latent
dimensions of perceptual styles reliably
Why Has HumanâCarnivore Conflict Not Been Resolved in Namibia?
Humanâwildlife conflict has historically been portrayed as a management problem where solutions lie in technical changes or financial incentives. However, recent research shows many conflicts stem from social, economic, and political drivers. We undertook qualitative data collection on livestock farms to determine whether relationships between farmers and their workers affected frequency of reported livestock depredation in Namibia. We found that the conflict was affected by social and economic inequalities embedded in the previous apartheid regime. Macro- and microlevel socioeconomic problems created an environment where livestock depredation was exacerbated by unmotivated farm workers. Poor treatment of workers by farmers resulted in vengeful behaviors, such as livestock theft and wildlife poaching. Successfully addressing this situation therefore requires recognition and understanding of its complexity, rather than reducing it to its most simplistic part
Effects of Cocaine-Kindling on the Expression of NMDA Receptors and Glutamate Levels in Mouse Brain
In the present study we examined the effects of cocaine seizure kindling on the expression of NMDA receptors and levels of extracellular glutamate in mouse brain. Quantitative autoradiography did not reveal any changes in binding of [3H] MK-801 to NMDA receptors in several brain regions. Likewise, in situ hybridization and Western blotting revealed no alteration in expression of the NMDA receptor subunits, NR1 and NR2B. Basal overflow of glutamate in the ventral hippocampus determined by microdialysis in freely moving animals also did not differ between cocaine-kindled and control groups. Perfusion with the selective excitatory amino acid transporter inhibitor, pyrrolidine-2,4-dicarboxylic acid (tPDC, 0.6Â mM), increased glutamate overflow confirming transport inhibition. Importantly, KCl-evoked glutamate overflow under tPDC perfusion was significantly higher in cocaine-kindled mice than in control mice. These data suggest that enhancement of depolarization stimulated glutamate release may be one of the mechanisms underlying the development of increased seizure susceptibility after cocaine kindling
The Work of the Course: validity and reliability in assessing English Literature
© 2017 National Association for the Teaching of English This article reflects on the values and practices of a revolutionary UK A level (senior secondary) course that achieved a high degree of validity and reliability in assessing the study of English literature. John Hodgson and Bill Greenwell were involved in its teaching and assessment from an early stage, and Greenwell's comments on an early draft of the article have been incorporated. The practice of literary response enshrined in the course was based on a striking application of âpersonal responseâ to literature, gave students opportunities to show capability in studying and writing a range of literary styles and genres, and engaged teachers regionally and nationally in a developed professional community of practice. It remains a touchstone of quality as well as of innovation in English curriculum and assessment
Bilateral cystoid macular edema following docetaxel chemotherapy in a patient with retinitis pigmentosa: a case report.
BACKGROUND: Docetaxel is a chemotherapeutic agent of the taxane class of drugs for the treatment of breast cancer. We present a female patient who noted decreased vision after docetaxel treatment. CASE PRESENTATION: A 45-year-old female patient received docetaxel treatment after resection of a breast carcinoma. Funduscopy and optical coherence tomography (OCT) showed cystoid macular edema on both eyes. Dilated funduscopy also showed bone spicule-like pigmented deposits, typical for retinitis pigmentosa. Besides the fundus appearance restricted peripheral vision and scotopic electroretinogram confirmed the diagnosis of retinitis pigmentosa. Chemotherapy was discontinued following a consulation with the oncologist of the patient. After five weeks, visual acuity improved significantly along with decrease of retinal thickness measured by OCT. CONCLUSION: Docetaxel may cause ocular adverse effects such as cystoid macular edema. Ophthalmological examination is warranted for patients with visual complaints during docetaxel chemotherapy
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