Many graphics applications today have to cope with large amounts of data. A popular approach to reduce the amount of geometry to be rendered is to precompute visibility in order to render only objects that can be seen from the given viewpoint. This paper presents one technique to achieve this, potentially visible sets (PVS). These sets are used to avoid rendering hidden objects, especially geom...

Let X be a finite set, N be a reticulation-visible network on X, and T be a rooted binary phylogenetic tree. We show that there is a polynomial-time algorithm for deciding whether or not N displays T . Furthermore, for all |X| ≥ 1, we show that N has at most 8|X| − 7 vertices in total and at most 3|X| − 3 reticulation vertices, and that these upper bounds are sharp.

In two experiments we measured object recognition performance as a function of delay. In Experiment 1 we presented half of an image of an object, and then the other half after a variable delay. Objects were subdivided into top versus bottom halves, left versus right halves, or vertical strips. In Experiment 2 we separated the low (LSF) and high spatial frequency (HSF) components of an image, an...

a useful nanophotocatalyst (la,s-tio2) was prepared by a sol-gel method and characterized by uv–vis diffuse reflectance spectroscopy (drs), x-ray diffraction (xrd), photoluminescence emission spectroscopy (pl) and scanning electron microscopy (fesem). the results showed that the la,s-tio2, which calcined at 550 °c, contained only anatase phaseand its crystal size was 23 nm. in addition, the fes...

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Microfabrication of graphene devices used in many experimental studies currently relies on the fact that graphene crystallites can be visualized using optical microscopy if prepared on top of Si wafers with a certain thickness of SiO2. We study graphene’s visibility and show that it depends strongly on both thickness of SiO2 and light wavelength. We have found that by using monochromatic illumi...

We introduce the visible k nearest neighbor (VkNN) query, which finds the k nearest objects that are visible to a query point. We also propose an algorithm to efficiently process the VkNN query. We compute the visible neighbors incrementally as we enlarge the search space. Our algorithm dramatically reduces the search cost compared to existing methods that require the computation of the visibil...

Today many systems exist to generate geometric m dels of existing scenes and objects. However, very few systems store accurate data about surface appearance such as colors and textures. One way to capture surface texture data is to record a series of images that, collectively, captures all visible surfaces of the object. Finding good viewpoints for this task is not easy. This paper presents a n...

There would be no population problems if people were not concerned about the evidently increasing difficulties of survival. Such is not the case as is evident in the global efforts for economic and social development. Yet, in the minds of most people the population question as a "situation" or a "problem" does not exist. When its reality is asserted by others, it is frequently regarded as a ...