Transforming triangulations in polygonal domains

In this paper we prove that it is possible to transform every triangulation of a set points inside a polygonal domain in the plane into every other triangulation of the same set of points using only operations of swapping diagonals in convex quadrilaterals.     

A 4-point interpolatory subdivision scheme for curve design

A 4-point interpolatory subdivision scheme with a tension parameter is analysed. It is shown that for a certain range of the tension parameter the resulting curve is C¹. The role of the tension parameter is demonstrated by a few examples. The application to surfaces and some further potential generalizations are discussed.     

Predicting the near and distant future.

Four studies investigated individuals' confidence in predicting near future and distant future outcomes. Study 1 found that participants were more confident in theory-based predictions of psychological experiments when these experiments were expected to take place in the more distant future. Studies 2-4 examined participants' confidence in predicting their performance on near and distant future tests. These studies found that in predicting their more distant future performance, participants disregarded the format of the questions (e.g., multiple choice vs. open ended) and relied, instead, on their perceived general knowledge (e.g., history knowledge). Together, the present studies demonstrate that predictions of the more distant future are based on relatively abstract information. Individuals feel more confident in predicting the distant future than the near future when the predictions concern outcomes that are implied by relatively abstract information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The role of attribution of motivation in producing postsuppressional rebound.

Three studies demonstrated that postsuppressional rebound (PSR) may be both reduced and enhanced by manipulating people's attributions about why they experience difficulty during suppression. Telling participants that suppression failures indicate a high motivation to use the suppressed construct produced more PSR than telling them that suppression failures indicate a low motivation to use the construct (Study 1). Telling participants that an external stimulus would make suppression easy produced more PSR than telling them that it would make suppression difficult (Study 2). Telling participants that suppressing a stereotype is difficult and unindicative of prejudice eliminated PSR (Study 3). These results support the notion that PSR occurs because people infer from the difficulty experienced during suppression and from suppression failures that they are motivated to use the suppressed construct. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Politeness and psychological distance: A construal level perspective.

According to politeness theory (P. Brown & S. Levinson, 1987), politeness serves to both reflect and regulate social distance. On the basis of this notion and on construal level theory (N. Liberman & Y. Trope, 2008; N. Liberman, Y. Trope, & E. Stephan, 2007), it was predicted that politeness would be related to abstract construal, temporal distance, and spatial distance. Eight studies supported this prediction. Politeness increased when the addressees were construed abstractly (Study 1), were temporally distant (Studies 2, 3), and were spatially distant (Study 4). It was also found that increasing politeness produced abstract construals (Study 5), greater temporal distance (Study 6), and greater spatial distance (Study 7, 8). These findings shed light on the way politeness operates in different cultures and is conveyed in different languages, and they support the idea that dimensions of psychological distance are interrelated. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Low bit-rate image coding using adaptive geometric piecewise polynomial approximation.

We present a new image coding algorithm, the geometric piecewise polynomials (GPP) method, that draws on recent developments in the theory of adaptive multivariate piecewise polynomials approximation. The algorithm relies on a segmentation stage whose goal is to minimize a functional that is conceptually similar to the Mumford-Shah functional except that it measures the smoothness of the segmentation instead of the length. The initial segmentation is "pruned" and the remaining curve portions are lossy encoded. The image is then further partitioned and approximated by low order polynomials on the subdomains. We show examples where our algorithm outperforms state-of-the-art wavelet coding in the low bit-rate range. The GPP algorithm significantly outperforms wavelet based coding methods on graphic and cartoon images. Also, at the bit rate 0.05 bits per pixel, the GPP algorithm achieves on the test image Cameraman, which has a geometric structure, a PSNR of 21.5 dB, while the JPEG2000 Kakadu software obtains PSNR of 20 dB. For the test image Lena, the GPP algorithm obtains the same PSNR as JPEG2000, but with better visual quality at 0.03 bpp.