Standardization of Rational Bézier Surfaces

National audienceThe sufficient and necessary condition for the existence of linear Möbius transformations that can standardize the rational Bézier surfaces is given based on Möbius reparameterization theorem. To obtain the standard form of an arbitrary cubic rational Bézier surface, we then present a quadratic reparameterization algorithm to reparameterize the surface so that all the corner weights of the surface are equal to one. Examples are included to show the performance of the new method.

Simulation of bubbles

International audienceWe present a novel framework based on a continuous fluid simulator for general simulation of realistic bubbles, with which we can handle as many significant dynamic bubble effects as possible. To capture a very thin liquid film of bubbles, we have developed a regional level set method allowing multi-manifold interface tracking. Based on the definitions of regional distance and its five operators, the implementation of the regional level set method is very easy. An implicit surface of liquid film with arbitrary thickness can be reconstructed from the regional level set function. To overcome the numerical instability problem, we exploit a new semi-implicit surface tension model which is unconditionally stable and makes the simulation of surface tension dominated phenomena much more efficient. An approximated film thickness evolution model is proposed to control the bubble's lifecycle. All these new techniques combine into a general framework that can produce various realistic dynamic effects of bubbles

Adaptive geometry compression based on 4-point interpolatory subdivision schemes with labels

International audienceWe propose an adaptive geometry compression method with labels based on 4-point interpolatory subdivision schemes. It can work on digital curves of arbitrary dimensions. With the geometry compression method, a digital curve is adaptively compressed into several segments with di®erent compression levels. Each segment is a 4-point subdivision curve with a subdivision step. Labels are recorded in data compression to facilitate merging those segments in data decompression. In the meantime, we provide high-speed 4-point interpolatory subdivision curve generation methods for e±ciently decompressing the compressed data. For an arbitrary positive integer k, formulae of the number of the resultant control points of a 4-point subdivision curve after k subdivision steps are provided. Some formulae for calculating points at the kth ubdivision step are presented as well. The time complexity of the new approaches is O(n), where n is the number of the points in the given digital curve. Examples are provided as well to illustrate the efficiency of the proposed approaches

An example on approximation by fat arcs and fat biarcs

International audienceFat arcs form bounding boxes for planar curves. An example on approximation by fat arcs, provided by Qun and Rokne, is corrected. The third derivative of the given curve segment under the polar coordinate system is increasing only at the beginning of the curve segment, and then decreasing, rather than monotonically increasing for the whole curve segment. Some numerical data are corrected as well

Visual Simulation of Multiple Unmixable Fluids

International audienceWe present a novel grid-based method for simulating multiple unmixable fluids moving and interacting. Unlike previous methods that can only represent the interface between two fluids (usually between liquid and gas), this method can handle an arbitrary number of fluids through multiple independent level sets coupled with a constrain condition. To capture the fluid surface more accurately, we extend the particle level set method to a multi-fluid version. It shares the advantages of the particle level set method, and has the ability to track the interfaces of multiple fluids. To handle the dynamic behavior of different fluids existing together, we use a multiphase fluid formulation based on a smooth weight function

Effect of Achyranthes bidentata Blume extract on carrageenan-induced chronic prostatitis in rats

Purpose: To investigate the effect of Achyranthes bidentata Blume. Extract (ABBE) on carrageenaninduced chronic prostatitis in rats.Methods: Experimental chronic non-bacterial prostatitis (CNP) was induced in rats by 1 % carrageenan (0.1 mL). Prostate index (PI) and prostate specific antigen (PSA) were determined after 3 weeks of adiministration. Relative inflammatory factors, viz, tumor necrosis factor-α (TNF-α), interleukin1β (IL-1β), cyclooxygenase-2 (COX-2), prostaglandin E2 (PEG2), transforming growth factor-β1 (TGF-β1) and connective tissue growth factor (CTGF) in the prostate tissues of all group rats were measured.Results: In CNP model, ABBE decreased PI and PSA compared with untreated control group (p < 0.01). Morphometric analysis showed a significant reduction in chronic inflammatory cell infiltrates and interstitial fibrosis compared to control group. Reduced values of TNF-α, IL-1β, COX-2, PEG2 were observed in ABBE-treated groups compared with model group respectively (p < 0.01). Moreover, the levels of TGF-β1 and CTGF in ABBE-treated groups were significantly lower, and in addition, there was alleviation of the inflammatory state of the prostate gland (p < 0.01).Conclusion: ABBE showed antichronic non-bacterial prostatitis effect by multiple ways in rats, thus indicating its potential suitability for the treatment of chronic prostatitis.Keywords: Achyranthes bidentata Blume., Chronic prostatitis, Inflammatory cel

Radio Polarization of BL Lacertae objects

In this paper, using the database of the university of Michigan Radio Astronomy Observatory (UMRAO) at three (4.8 GHz, 8 GHZ, and 14.5 GHz) radio frequencies, we studied the polarization properties for 47 BL Lacertae objects(38 radio selected BL Lacertae objects, 7 X-ray selected BL Lacertae, and two inter-middle objects (Mkn 421 and Mkn 501), and found that (1) The polarizations at higher radio frequency is higher than those at lower frequency, (2) The variability of polarization at higher radio frequency is higher than those at lower frequency, (3) The polarization is correlated with the radio spectral index, and (4) The polarization is correlated with core-dominance parameter for those objects with known core-dominance parameters suggesting that the relativistic beaming could explain the polarization characteristic of BL Lacs.Comment: 5 pages, 3 figures, 1 table. PASJ, in pres