Fast and effective feature-preserving mesh denoising

We present a simple and fast mesh denoising method, which can remove noise effectively, while preserving mesh features such as sharp edges and corners. The method consists of two stages. Firstly, noisy face normals are filtered iteratively by weighted averaging of neighboring face normals. Secondly, vertex positions are iteratively updated to agree with the denoised face normals. The weight function used during normal filtering is much simpler than that used in previous similar approaches, being simply a trimmed quadratic. This makes the algorithm both fast and simple to implement. Vertex position updating is based on the integration of surface normals using a least-squares error criterion. Like previous algorithms, we solve the least-squares problem by gradient descent, but whereas previous methods needed user input to determine the iteration step size, we determine it automatically. In addition, we prove the convergence of the vertex position updating approach. Analysis and experiments show the advantages of our proposed method over various earlier surface denoising methods.     

Profiles of Random Trees: Limit Theorems for Random Recursive Trees and Binary Search Trees

We prove convergence in distribution for the profile (the number of nodes at each level), normalized by its mean, of random recursive trees when the limit ratio α of the level and the logarithm of tree size lies in [0,e). Convergence of all moments is shown to hold only for α ∈ [0,1] (with only convergence of finite moments when α ∈ (1,e)). When the limit ratio is 0 or 1 for which the limit laws are both constant, we prove asymptotic normality for α = 0 and a "quicksort type" limit law for α = 1, the latter case having additionally a small range where there is no fixed limit law. Our tools are based on the contraction method and method of moments. Similar phenomena also hold for other classes of trees; we apply our tools to binary search trees and give a complete characterization of the profile. The profiles of these random trees represent concrete examples for which the range of convergence in distribution differs from that of convergence of all moments.     

A structured marketplace for arbitrary services

Creating simple marketplaces with common rules, that enable the dynamic selection and consumption of functionality, is the missing link to allow small businesses to enter the cloud, not only as consumers, but also as vendors. In this paper, we present the concepts behind a hybrid service and process repository that can act as the foundation for such a marketplace, as well as a prototype that allowed us to test various real-world scenarios. The advantage of a hybrid service and process repository is that, it not only holds a flat list of services, but also exposes a generic set of use cases, that it obtains information on how specific services can be used to implement the use cases as well as information to select services at run-time according to customer’s goal functions.     

3D characterization of hot metallic shells during industrial forging

During industrial forging of hot metallic shells, it is necessary to regularly measure the dimensions of the parts, especially the inner and outer diameters and the thickness of the walls. A forging sequence lasts 2 h or more during which the diameter of the shell is regularly measured in order to decide when to stop the forging process. For better working conditions, for the safety of the blacksmiths, and for a faster and more accurate measurement, we have developed a novel system based on two commercially available time of flight laser scanners for the measurement of the diameters of hot cylindrical metallic shells during the forging process. The advantages of using laser scanners are that they can be placed very far from the hot shell, more than 15 m, while at the same time giving an accurate point cloud from which three-dimensional views of the shell can be reconstructed and diameter measurements done. Moreover, more accurate measurement is achieved in less time with the laser system than with the conventional method using a large ruler. The system has been successfully used to measure the diameters of hot cylindrical metallic shells.     

The smooth (tractor) operator: insights of knowledge engineering

The design of and training for complex systems requires in-depth understanding of task demands imposed on users. In this project, we used the knowledge engineering approach (Bowles et al., 2004) to assess the task of mowing in a citrus grove. Knowledge engineering is divided into four phases: (1) Establish goals. We defined specific goals based on the stakeholders involved. The main goal was to identify operator demands to support improvement of the system. (2) Create a working model of the system. We reviewed product literature, analyzed the system, and conducted expert interviews. (3) Extract knowledge. We interviewed tractor operators to understand their knowledge base. (4) Structure knowledge. We analyzed and organized operator knowledge to inform project goals. We categorized the information and developed diagrams to display the knowledge effectively. This project illustrates the benefits of knowledge engineering as a qualitative research method to inform technology design and training.     

Hot-pressing behaviour of silicon carbide powders with additions of aluminium oxide

The hot-pressing behaviour of different silicon carbide powders (average particle sizes ranging from ～ 0.5 to 9 μm) with aluminium oxide additions ranging from 0.01 to 0.15 volume fractions was investigated. Using powders with an average particle size < 3 μm, densities ≥ 99% theoretical could be achieved at 1950° C (1 h) with 28 MN m^?2 for volume fractions of AI₂O₃ \(\bar > \) 0.02. A liquid phase forms at high temperatures which dissolves the silicon carbide particles to promote densification by a solution-reprecipitation mechanism.     

Sleeping Beauties in Psychology: Comparisons of "Hits" and "Missed Signals" in Psychological Journals.

Scientific publications tend to be forgotten quickly. A few works, however, are still cited 100 years and more after their publication. The author used bibliometric methods to compare "hits" (works noticed by the scientific community soon after their publication) with "missed signals" (works that went unnoticed until much later) by investigating 2 psychological journals founded in the 1890s: Zeitschrift für Psychologie and Psychological Review. All articles that were published in either of these journals up to 1920 and cited more than 25 times in the Web of Science up to the year 2000 were considered for inclusion in the analysis. It emerged that hits corresponded more closely to the focus of scientific attention at the time of publication than missed signals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An Extended Comparator Hypothesis Account of Superconditioning.

Three conditioned taste aversion experiments with rats investigated superconditioning. In each experiment, alternate exposures of 2 flavor compounds with a common element (i.e., AB/AS) were administered to establish an inhibitory relationship between the 2 unique elements, B and S, and prior to testing, S was paired with lithium chloride (LiCl). In Experiment 1, pairings of a neutral cue (X) with S in compound with B after the AB/AS exposures resulted in superconditioning between X and S. Extinction of the common element (A) just before the S-LiCl pairing attenuated both the inhibitory relationship between B and S (Experiment 2) and superconditioning between X and S (Experiment 3). These observations suggest that superconditioning consists of enhanced performance rather than enhanced associative acquisition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Vortex Matter in Superconductor / Ferromagnet Hybrids

No Heading Vortex pinning in type-II superconducting films can be effectively controlled by combining these films with different ferromagnetic nanostructures. In this article an overview is presented of divergent types of ferromagnetic pinning centers. The investigated hybrid structures consist of Pb films that are deposited on top of arrays of ferromagnetic dots with in-plane magnetization (IPM) or out-of-plane magnetization (OPM), ferromagnetic films with IPM or OPM that contain arrays of submicron holes (antidots), or continuous films with OPM and a magnetic domain structure. Interesting effects such as field-polarity dependent vortex pinning and the dependence of the pinning strength on the domain structure of the ferromagnet are observed. Our experiments demonstrate that vortex pinning in superconductors is strongly influenced by the magnetic properties of the different ferromagnetic pinning centers.PACS numbers: 74.25.Qt, 74.25.Ha, 74.78.Na     

Vortex matter in superconductor/ferromagnet hybrids

Vortex pinning in type-II superconducting films can be effectively controlled by combining these films with different ferromagnetic nanostructures. In this article an overview is presented of different types of ferromagnetic pinning centers. The investigated hybrid structures consist of Pb films that are deposited on top of arrays of ferromagnetic dots with in-plane magnetization (IMP) or out-of-plane magnetization (OPM), ferromagnetic films with IPM or OPM that contain arrays of submicron holes (antidots), or continuous films with OPM and a magnetic domain structure. Interesting effects such as field-polarity dependent vortex pinning and the dependence of the pinning strength on the domain structure of the ferromagnet are observed. Our experiments demonstrate that vortex pinning in superconductors is strongly influenced by the magnetic properties of the different ferromagnetic pinning centers.