This paper presents a forward mapping rendering algo-rithm to display regular volumetric grids that may not have the same spacings in the three grid directions. It takes advantage of the fact that convolution can be thought of as distributing energy from input samples into space. The renderer calculates an image plane footprint for each data sample and uses the footprint to spread the sample's energy onto the image plane. A result of the technique is that the forward mapping algorithm can support perspective without excessive cost, and support adaptive resampling of the three-dimensional data set during image generation.

We devise new numerical algorithms, called PSC algorithms, for following fronts propagating with curvature-dependent speed. The speed may be an arbitrary function of curvature, and the front can also be passively advected by an underlying flow. These algorithms approximate the equations of motion

in converging to the Pareto-optimal front (e.g., multimodality and deception). By investigating these different problem features separately, it is possible to predict the kind of problems to which a certain technique is or is not well suited. However, in contrast to what was suspected beforehand

are negatively related over time to contemporaneous unexpected illiquidity. The illiquidity measure here is the average across stocks of the daily ratio of absolute stock return to dollar volume, which is easily obtained from daily stock data for long time series in most stock markets. Illiquidity affects more

this paper what we know about foreign trade and in what ways our understanding has improved as a result of the last 20 years of research

"He who can, does. He who cannot, teaches. “ 1 don't know in what fit of pique George Bernard Shaw wrote that infamous aphorism, words that have plagued members of the teach-ing profession for nearly a century. They are found in "Maxims for Revolutionists, " an appendix to his play Man and Superman. "He who can, does. He who cannot, teaches" is a calamitous insult to our profes-sion, yet one readily repeated even by teachers. More worrisome, its philosophy often appears to under-lie the policies concerning the occu-pation and activities of teaching. Where did such a demeaning im-age of the teacher's capacities ori-ginate? How long have we been bur-dened by assumptions of ignorance and ineptitude within the teaching corps? Is Shaw to be treated as the last word on what teachers know and don't know, or do and can't do? Yesterday's Examinations We begin our inquiry into concep-tions of teacher knowledge with the tests for teachers that were used in this country during the last century This paper was a Presidential Ad-dress at the 1985 annual meeting of

Image-space simplifications have been used to accelerate the calculation of computer graphic images since the dawn of visual simulation. Texture mapping has been used to provide a means by which images may themselves be used as display primitives. The work reported by this paper endeavors to carry this concept to its logical extreme by using interpolated images to portray three-dimensional scenes. The special-effects technique of morphing, which combines interpolation of texture maps and their shape, is applied to computing arbitrary intermediate frames from an array of prestored images. If the images are a structured set of views of a 3D object or scene, intermediate frames derived by morphing can be used to approximate intermediate 3D transformations of the object or scene. Using the view interpolation approach to synthesize 3D scenes has two main advantages. First, the 3D representation of the scene may be replaced with images. Second, the image synthesis time is independent of the scene complexity. The correspondence between images, required for the morphing method, can be predetermined automatically using the range data associated with the images. The method is further accelerated by a quadtree decomposition and a view-independent visible priority. Our experiments have shown that the morphing can be performed at interactive rates on today’s high-end personal computers. Potential applications of the method include virtual holograms, a walkthrough in a virtual environment, image-based primitives and incremental rendering. The method also can be used to greatly accelerate the computation of motion blur and soft shadows cast by area light sources.

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I propose a network/search view of international trade in differentiated products. I present evidence that supports the view that proximity and common language/colonial ties are more important for differentiated products than for products traded on organized exchanges in matching international buyers and sellers, and that search barriers to trade are higher for differentiated than for homogeneous products. I also discuss alternative

ABSTRACT: Affect is considered by most contempo-rary theories to be postcognitive, that is, to occur only after considerable cognitive operations have been ac-complished. Yet a number of experimental results on preferences, attitudes, impression formation, and de-_ cision making, as well as some clinical phenomena, suggest that affective judgments may be fairly inde-pendent of, and precede in time, the sorts of percep-tual and cognitive operations commonly assumed to be the basis of these affective judgments. Affective re-actions to stimuli are often the very first reactions of the organism, and for lower organisms they are the dominant reactions. Affective reactions can occur without extensive perceptual and cognitive encoding, are made with greater confidence than cognitive judg-