Order-k α-hulls and α-shapes

We introduce order-k α-hulls and α-shapes – generalizations of α-hulls and α-shapes. Being also a generalization of k-hull (known in statistics as “k-depth contour”), order-k α-hull provides a link between shape reconstruction and statistical depth. As a generalization of α-hull, order-k α-hull gives a robust shape estimation by ignoring locally up to k outliers in a point set. Order-k α-shape produces an “inner” shape of the set, with the amount of “digging” into the points controlled by k. As a generalization of k-hull, order-k α-hull is capable of determining “deep” points amidst samples from a multimodal distribution: it correctly identifies points which lie outside clusters of samples.The order-k α-hulls and α-shapes are related to order-k Voronoi diagrams in the same way in which α-hulls and α-shapes are related to Voronoi diagrams. This implies that order-k α-hull and α-shape can be readily built from order-k Voronoi diagram, and that the number of different order-k α-shapes for all possible values of α is proportional to the complexity of order-k Voronoi diagram.     

烟气脱硫技术在浮法玻璃线上的应用

简介了烟气脱硫技术在浮法玻璃线上的应用情况,以工程实例详细介绍该技术在某浮法玻璃线上的设计、实施、应用情况以及重点、难点问题的处理,为该技术在浮法玻璃线的应用提供借鉴和参考.     

An analysis of transport phenomena for multi-solid particle systems at higher reynolds numbers by a standard karman—pohlhausen method—I Momentum transfer

Using the concentric spheres free surface model and a standard 4th polynomial Karman—Pohlansen method, the dimensionless tangential stress distribution, and the dimensionless pressure distribution around a solid sphere in a swarm, and the viscous, form and total drag coefficient for multi-solid particle systems were computed numerically at higher Reynolds numbers. The void function obtained from the drag coefficient for multiparticle system was comparative to the experimental data. The friction factor for multi-particle systems so computed agreed with the experimental data of packed and distended beds.     

Hero Wavelength Spectral Sampling

We present a spectral rendering technique that offers a compelling set of advantages over existing approaches. The key idea is to propagate energy along paths for a small, constant number of changing wavelengths. The first of these, the hero wavelength, is randomly sampled for each path, and all directional sampling is solely based on it. The additional wavelengths are placed at equal distances from the hero wavelength, so that all path wavelengths together always evenly cover the visible range. A related technique, spectral multiple importance sampling, was already introduced a few years ago. We propose a simplified and optimised version of this approach which is easier to implement, has good performance characteristics, and is actually more powerful than the original method. Our proposed method is also superior to techniques which use a static spectral representation, as it does not suffer from any inherent representation bias. We demonstrate the performance of our method in several application areas that are of critical importance for production work, such as fidelity of colour reproduction, sub‐surface scattering, dispersion and volumetric effects. We also discuss how to couple our proposed approach with several technologies that are important in current production systems, such as photon maps, bidirectional path tracing, environment maps, and participating media.     

A Projective Framework for Polyhedral Mesh Modelling

We present a novel framework for polyhedral mesh editing with face‐based projective maps that preserves planarity by definition. Such meshes are essential in the field of architectural design and rationalization. By using homogeneous coordinates to describe vertices, we can parametrize the entire shape space of planar‐preserving deformations with bilinear equations. The generality of this space allows for polyhedral geometric processing methods to be conducted with ease. We demonstrate its usefulness in planar‐quadrilateral mesh subdivision, a resulting multi‐resolution editing algorithm, and novel shape‐space exploration with prescribed transformations. Furthermore, we show that our shape space is a discretization of a continuous space of conjugate‐preserving projective transformation fields on surfaces. Our shape space directly addresses planar‐quad meshes, on which we put a focus, and we further show that our framework naturally extends to meshes with faces of more than four vertices as well.     

两种不同原料制备无粘结剂高强度炭材料的研究

分别以生石油焦和煤系原料改性炭粉为原料成功制得了无粘结荆高强度炭材料。实验表明：原料挥发分含量较高对粉料的成型有利，但挥发分含量过高，不利于无粘结剂炭材料的烧结；另外，随着成型压力的增加，生坯密度和无粘结荆炭材料烧结制品的密度都呈升高的趋势。研究结果表明：成型压力为IOOMPa，烧结温度为1000℃，生石油焦粉制得的无粘结剂炭材料的抗折强度为42．90MPa，抗压强度为90．23MPa；煤系原料改性炭粉制得的无粘结剂炭材料的抗折强度为61．58MPa，抗压强度为116．12MPa。     

Switch on to games: Can digital games aid post-work recovery?

Recovery is a necessary factor in avoiding work-related strain and in feeling prepared for the next day of work. In order for recovery to be successful, an individual must experience psychological detachment from work, relaxation, mastery experiences and a sense of control, all of which have been argued to be assisted by digital game use. However, it is unclear whether these associations will be greater for certain digital game genres, or whether this would extend to other recovery-related outcomes, for instance work home interference (WHI), where the stress from work interferes with home-life. These factors may be vital in determining whether interventions aimed at improving recovery using digital games would be effective, and what form these should take. The present research surveyed 491 participants and found that the total number of hours spent playing digital games per week was positively correlated with overall recovery. Correlations varied with genre, highlighting the importance of game characteristics in this relationship: first person shooters and action games were most highly correlated with recovery. Moreover, digital game use was not related to a reduction in work–home interference. When restricting the analysis to gamers who report to have developed online relationships, online social support mediated the relationship between digital game use and recovery. Results are discussed in terms of how digital games may be utilised to improve recovery and reduce work-related stress.     

Real-time facial animation on mobile devices

We present a performance-based facial animation system capable of running on mobile devices at real-time frame rates. A key component of our system is a novel regression algorithm that accurately infers the facial motion parameters from 2D video frames of an ordinary web camera. Compared with the state-of-the-art facial shape regression algorithm [1], which takes a two-step procedure to track facial animations (i.e., first regressing the 3D positions of facial landmarks, and then computing the head poses and expression coefficients), we directly regress the head poses and expression coefficients. This one-step approach greatly reduces the dimension of the regression target and significantly improves the tracking performance while preserving the tracking accuracy. We further propose to collect the training images of the user under different lighting environments, and make use of the data to learn a user-specific regressor, which can robustly handle lighting changes that frequently occur when using mobile devices.