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排序方式: 共有270条查询结果,搜索用时 15 毫秒
61.
Analyzing large and complex datasets for critical decision making can benefit from a collective effort involving a team of analysts. However, insights and findings from different analysts are often incomplete, disconnected, or even conflicting. Most existing analysis tools lack proper support for examining and resolving the conflicts among the findings in order to consolidate the results of collaborative data analysis. In this paper, we present CoVA, a visual analytics system incorporating conflict detection and resolution for supporting asynchronous collaborative data analysis. By using a declarative visualization language and graph representation for managing insights and insight provenance, CoVA effectively leverages distributed revision control workflow from software engineering to automatically detect and properly resolve conflicts in collaborative analysis results. In addition, CoVA provides an effective visual interface for resolving conflicts as well as combining the analysis results. We conduct a user study to evaluate CoVA for collaborative data analysis. The results show that CoVA allows better understanding and use of the findings from different analysts. 相似文献
62.
Yang Liu Yufeng Zheng Xie‐Hui Chen Jian‐An Yang Haobo Pan Dafu Chen Luning Wang Jialiang Zhang Donghui Zhu Shuilin Wu Kelvin Wai Kwok Yeung Rong‐Chang Zeng Yong Han Shaokang Guan 《Advanced functional materials》2019,29(18)
Until now there has been no fundamental theory applicable for biodegradable metals (BMs). First, this paper optimizes the definition of BMs given in 2014. Second, the dual criteria of biodegradability and biocompatibility are proposed for BMs, and all metallic elements in the periodic table with accessible data are screened on the basis of these criteria. Regarding biodegradability, electrode potential, reactivity series, galvanic series, Pilling–Bedworth ratio, and Pourbaix diagrams are all adopted as parameters to classify the degradable and nondegradable nature of a material, especially in a physiological environment. Considering the biocompatibility at different levels, cellular biocompatibility, tissue biocompatibility, and human/clinical related biocompatibility parameters are put forward to comprehensively evaluate the biosafety of BMs. Third, for the material design of BMs, mechanical properties, chemical properties, physical properties and biological properties should be considered and balanced to guarantee that the degradation behavior of BMs match well with a tissue regeneration/repair procedure as the function of time and spatial location. Besides the selected metallic elements, some nonmetallic elements are selected as suitable alloying elements for BMs. Finally, five classification/research directions for future BMs are proposed: biodegradable pure metals, crystalline alloys, bulk metallic glasses, high entropy alloys, and metal matrix composites. 相似文献
63.
We present a robust global and local mixture distance (GLMD) based non-rigid point set registration method which consists of an alternating two-step process: correspondence estimation and transformation updating. We first define two distance features for measuring global and local structural differences between two point sets, respectively. The two distances are then combined to form a GLMD based cost matrix which provides a flexible way to estimate correspondences by minimizing global or local structural differences using a linear assignment solution. To improve the correspondence estimation and enhance the interaction between the two steps, an annealing scheme is designed to gradually change the cost minimization from local to global and the thin plate spline transformation from rigid to non-rigid during registration. We test the performance of our method in contour registration, sequence images and real images, and compare with six state-of-the-art methods where our method shows the best alignments in most scenarios. 相似文献
64.
Muhammet Fatih Toksoy William Rafaniello Kelvin Yu Xie Luoning Ma Kevin Jude Hemker Richard Alan Haber 《International Journal of Applied Ceramic Technology》2017,14(3):443-453
Submicrometer boron carbide powders were synthesized using rapid carbothermal reduction (RCR) method. Synthesized boron carbide powders had smaller particle size, lower free carbon, and high density of twins compared to commercial samples. Powders were sintered using spark plasma sintering at different temperatures and dwell times to compare sintering behavior. Synthesized boron carbide powders reached >99% TD at lower temperature and shorter dwell times compared to commercial powders. Improved microhardness observed in the densified RCR samples was likely caused by the combination of higher purity, better stoichiometry control, finer grain size, and a higher density of twin boundaries. 相似文献
65.
基于启发式搜索分离向量的凸多面体碰撞检测 总被引:7,自引:0,他引:7
碰撞检测是计算机模拟物理过程的基础,在计算机图形学、CAD/CAM、虚拟现实和机器人等领域有着广泛的应用.该文给出了一个新的用于凸多面体碰撞检测的算法——HP-jump.HP-jump建立了一个有效的碰撞检测模型用于报告物体的碰撞,同时提供了一个快速的启发式的策略用于搜索两个凸多面体的分离向量.该算法是利用凸多面体的层次表示来搜索支撑顶点对,用平衡二叉树来记录球面凸多边形的顶点,同时还利用了时间、空间相关性,这些都加速了算法的执行.该文的最后给出了HP-jump与GJK,I-COLLIDE算法的比较. 相似文献
66.
Kelvin Y. Xie Yanbo Wang Yonghao Zhao Li Chang Guocheng Wang Zibin Chen Yang Cao Xiaozhou Liao Enrique J. Lavernia Ruslan Z. Valiev Babak Sarrafpour Hans Zoellner Simon P. Ringer 《Materials science & engineering. C, Materials for biological applications》2013,33(6):3530-3536
High strength, low Young's modulus and good biocompatibility are desirable but difficult to simultaneously achieve in metallic implant materials for load bearing applications, and these impose significant challenges in material design. Here we report that a nano-grained β-Ti alloy prepared by high-pressure torsion exhibits remarkable mechanical and biological properties. The hardness and modulus of the nano-grained Ti alloy were respectively 23% higher and 34% lower than those of its coarse-grained counterpart. Fibroblast cell attachment and proliferation were enhanced, demonstrating good in vitro biocompatibility of the nano-grained Ti alloy, consistent with demonstrated increased nano-roughness on the nano-grained Ti alloy. Results suggest that the nano-grained β-Ti alloy may have significant application as an implant material in dental and orthopedic applications. 相似文献
67.
Alfred Z. Msezane Zineb Felfli Kelvin Suggs Aron Tesfamichael Xiao-Qian Wang 《Gold bulletin》2012,45(3):127-135
The oxidation of CH4 has been investigated in the presence and absence of the atomic Au− ion catalyst. We have employed the first principles density functional theory (DFT) and dispersion-corrected DFT calculations for the transition state on the Au− ion and analyzed the thermodynamics properties of the reactions as well. Our results demonstrate that atomic gold anions could be used to catalyze CH4 into valuable industrial products without the emission of CO2, thereby making gold extremely valuable. The fundamental mechanism involves breaking the C–H bond through the formation of the anionic Au−(CH4) molecular complex permitting the oxidation of CH4 to methanol at the temperature of 325 K which is below that of CO2 emission. Potentially, this could significantly impact the quality of our environment. 相似文献
68.
Fama Rosemary; Sullivan Edith V.; Shear Paula K.; Cahn-Weiner Deborah A.; Marsh Laura; Lim Kelvin O.; Yesavage Jerome A.; Tinklenberg Jared R.; Pfefferbaum Adolf 《Canadian Metallurgical Quarterly》2000,14(1):29
This study examined the relationships between regional brain volumes and semantic, phonological, and nonverbal fluency in 32 participants with Alzheimer's disease (AD). Object but not animal semantic fluency correlated with frontal and temporal gray matter volumes. Phonological fluency was not significantly associated with any brain volume examined. Nonverbal fluency was selectively associated with bilateral frontal gray matter volumes. Hippocampal volumes, although markedly reduced in these patients, were not related to any of the fluency measures. Results lend evidence to the importance of the frontal lobes in the directed generation of nonverbal and verbal exemplars by AD patients. Furthermore, both left and right-hemisphere regions contribute to the generation of verbal and nonverbal exemplars. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
69.
Cerebellar volume decline in normal aging, alcoholism, and Korsakoff's syndrome: Relation to ataxia.
Sullivan Edith V.; Deshmukh Anjali; Desmond John E.; Lim Kelvin O.; Pfefferbaum Adolf 《Canadian Metallurgical Quarterly》2000,14(3):341
The authors used magnetic resonance imaging to measure gray and white matter volumes in cerebellar hemispheres and 4 vermian regions in 61 normal control (NC) men aged 23–72 years, 25 men with uncomplicated alcoholism (ALC), and 8 men and 1 woman with alcoholic Korsakoff's syndrome (KS). NC and ALC took quantitative gait and balance tests. Gray but not white matter volume declined with normal age in both hemispheres and anterior–superior vermis. ALC had gray but not white matter cerebellar hemisphere volume deficits, whereas KS had deficits in both tissue types. ALC and KS had gray and white matter volume deficits in anterior superior but not posterior inferior vermis. ALC had a 1 SD ataxia deficit, significantly and selectively correlated with white matter volume in anterior superior vermis. Regional distribution but not severity of cerebellar volume deficits is similar in alcoholic individuals whether or not complicated by KS and relates to ataxia. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
70.
A Comparative Study of Boundary Control With First- and Second-Order Switching Surfaces for Buck Converters Operating in DCM 总被引:1,自引:0,他引:1
Kelvin Ka-Sing Leung Henry Shu-hung Chung 《Power Electronics, IEEE Transactions on》2007,22(4):1196-1209
A performance comparison of boundary control with the first-(sigma1) and second-order(sigma2) switching surfaces for buck converters operating in discontinuous conduction mode (DCM) is presented in this paper. Performance attributes under investigation include the average output voltage, output ripple voltage, switching frequency, parametric sensitivities to the component values, and large signal characteristics. Due to the presence of the output hysteresis band, an additional switching boundary formed by the zero-inductor-current trajectory is created. This phenomenon causes a shift of the operating point in converters with sigma1. Conversely, the operating point remains unchanged in converters with sigma2. As well as in continuous conduction mode (CCM), sigma2 can make the converter revert to the steady-state in two switching actions in DCM and gives better static and dynamic responses than in both CCM and DCM. Most importantly, its control law and settings are applicable for both modes. Experimental results of a prototype are found to be in good agreement with theoretical predictions. 相似文献