Smooth Shape‐Aware Functions with Controlled Extrema

Functions that optimize Laplacian‐based energies have become popular in geometry processing, e.g. for shape deformation, smoothing, multiscale kernel construction and interpolation. Minimizers of Dirichlet energies, or solutions of Laplace equations, are harmonic functions that enjoy the maximum principle, ensuring no spurious local extrema in the interior of the solved domain occur. However, these functions are only C⁰ at the constrained points, which often causes smoothness problems. For this reason, many applications optimize higher‐order Laplacian energies such as biharmonic or triharmonic. Their minimizers exhibit increasing orders of continuity but lose the maximum principle and show oscillations. In this work, we identify characteristic artifacts caused by spurious local extrema, and provide a framework for minimizing quadratic energies on manifolds while constraining the solution to obey the maximum principle in the solved region. Our framework allows the user to specify locations and values of desired local maxima and minima, while preventing any other local extrema. We demonstrate our method on the smoothness energies corresponding to popular polyharmonic functions and show its usefulness for fast handle‐based shape deformation, controllable color diffusion, and topologically‐constrained data smoothing.     

Semat—Three Year Vision

The purpose of writing this Three Year Vision paper is threefold. Firstly, it briefly recaps the progress Semat has made thus far; secondly, it lays out the future directions for people working actively within the Semat community; thirdly, it provides the background for seeking funding support from agencies, such as the European Community and the like. Funding support is necessary to sustain the ongoing activities of Semat and its growth into a broader community effort, as most people working within Semat are volunteers. As such, the paper may be both too much and too little for the wider supporter base. However, we intend to make our work fully transparent, hence, we publish it widely. We seek feedback and comments from supporters and signatories in order to improve the vision. In this context, other companion papers are being written to better address the specific needs for the practitioners, the industry and the academia.     

What localizes beneath: A metric multisensor localization and mapping system for autonomous underground mining vehicles

Robustly and accurately localizing vehicles in underground mines is particularly challenging due to the unavailability of GPS, variable and often poor lighting conditions, visual aliasing in long tunnels, and airborne dust and water. In this paper, we present a novel, infrastructure‐less, multisensor localization method for robust autonomous operation within underground mines. The proposed method integrates with existing mine site commissioning and operation procedures and includes both an offline map‐building process and an online localization algorithm. The approach combines the strengths of visual‐based place recognition, LIDAR‐based localization, and odometry in a particle filter fusion process. We provide an extensive experimental validation using new large data sets acquired in two operational Australian underground hard‐rock mines (including a 600m‐deep multilevel mine with approximately 33 km of mapping data and 7 km of vehicle localization) by actual mining vehicles during production operations. We demonstrate a significant increase in localization accuracy over prior state‐of‐the‐art SLAM research systems and real‐time operation, with processing times in the order of 10 Hz. We present results showing a mean error of 0.68 m from the Queensland Mine data set and 1.32 m from the New South Wales Mine data set and at least 86% reduction in error compared with prior state of the art. We also analyze the impact of the particle filter parameters with respect to localization accuracy. Together this study represents a new approach to positioning systems for currently deployed autonomous vehicles within underground mine environments.     

Common issues in discrete optimization and discrete-eventsimulation

This note studies and exploits common issues between discrete-event simulation models and algorithms for discrete optimization problems to prove that two discrete-event simulation search problems are NP-hard. More specifically, NEIGHBORHOOD seeks a sequence of events such that two distinct states can be accessed, one state after executing all but the last k events and another state after executing all the events, while INITIALIZE seeks a sequence of events such that executing the sequence with one particular initial event results in a particular state being reached, while for a second initial event, that particular state cannot be reached. Implications of these results for discrete-event simulation modeling and analysis (e.g., assessing when steady state, termination conditions have been reached, or optimal input parameters values for simulation optimization have been established) as well as for discrete optimization problems (e.g., assessing a priori the effectiveness of a neighborhood for simulated annealing or tabu search) are discussed     

Designing and equipping a usability laboratory

The goal of usability lab design is to create a space where high quality data capture occurs in an environment that looks and feels like the workplace of the product that is being tested. The lab must be part recording studio and part flexible work environment. Since most work environments are not recording studios, achieving a balance between simulation of the work environment and high quality data capture presents a challenge to usability lab designers. Steps can be taken with a user-centred design process to insure that a usability lab design meets this goal. This paper describes such a user-centred design process and how it. in combination with practical architectural and equipment guidelines derived from the authors' past experience, can be used in the design and redesign of future labs. The authors also discuss what changed in the present lab at NCR as a result of these guidelines.     

在磨难中坚持 在历练中成熟——高炼悸千锤酉炼的游戏人生

几周前,我在美国访问了一家州政府。他们将自己全新的企业软件外包给了一家基于美国的国际软件公司,我们姑且称这家公司为Smarty,合同总价达到数百万美金。合同中包括下面这些条款：     

Solid Geometry Processing on Deconstructed Domains

Many tasks in geometry processing are modelled as variational problems solved numerically using the finite element method. For solid shapes, this requires a volumetric discretization, such as a boundary conforming tetrahedral mesh. Unfortunately, tetrahedral meshing remains an open challenge and existing methods either struggle to conform to complex boundary surfaces or require manual intervention to prevent failure. Rather than create a single volumetric mesh for the entire shape, we advocate for solid geometry processing on deconstructed domains, where a large and complex shape is composed of overlapping solid subdomains. As each smaller and simpler part is now easier to tetrahedralize, the question becomes how to account for overlaps during problem modelling and how to couple solutions on each subdomain together algebraically. We explore how and why previous coupling methods fail, and propose a method that couples solid domains only along their boundary surfaces. We demonstrate the superiority of this method through empirical convergence tests and qualitative applications to solid geometry processing on a variety of popular second‐order and fourth‐order partial differential equations.     

UML的前途

UML（统一建模语言）成为标准已经超过12年了。在这些年里,人们对UML的看法各不相同,有喜爱的,也有讨厌的。在这篇文章中,我们将讨论当前UML规范的不足之处．并建议如何让它敏捷、更精益、更智慧、更有弹性——简而言之,     

Genetic and environmental bases of childhood antisocial behavior: A multi-informant twin study.

Genetic and environmental influences on childhood antisocial and aggressive behavior (ASB) during childhood were examined in 9- to 10-year-old twins, using a multi-informant approach. The sample (605 families of twins or triplets) was socioeconomically and ethnically diverse, representative of the culturally diverse urban population in Southern California. Measures of ASB included symptom counts for conduct disorder, ratings of aggression, delinquency, and psychopathic traits obtained through child self-reports, teacher, and caregiver ratings. Multivariate analysis revealed a common ASB factor across informants that was strongly heritable (heritability was .96), highlighting the importance of a broad, general measure obtained from multiple sources as a plausible construct for future investigations of specific genetic mechanisms in ASB. The best fitting multivariate model required informant-specific genetic, environmental, and rater effects for variation in observed ASB measures. The results suggest that parents, children, and teachers have only a partly "shared view" and that the additional factors that influence the "rater-specific" view of the child's antisocial behavior vary for different informants. This is the first study to demonstrate strong heritable effects on ASB in ethnically and economically diverse samples. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of microstructure on oxygen permeation in SrCo0.8Fe0.2O3−δ

The effect of microstructure on oxygen permeation in SrCo0.8Fe0.2O3– membranes was investigated using disc samples fabricated under different processing conditions of applied pressure and sintering temperature. The average grain size of the samples was found to remain unchanged as a function of applied pressure, but increased considerably when the sintering temperature was increased from 950 to 1200°C. This change in grain size has a strong effect on the oxygen permeation flux, which increased considerably as the grain size was decreased. The density as well as the microhardness of these samples were also measured and found to change slightly as the processing conditions were changed.