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51.
52.
The aim of this note is to examine the conditions of stability of a simple robotic task: we consider a one degree-of-freedom (dof) robot that collides with a spring-like environment with stiffness k, the goal being to stabilize the system in contact with the environment. We study conditions on the feedback gains that guarantee quadratic Lyapunov stability of the task with a well-conditioned solution to the Lyapunov equation. It is shown that when the environment's stiffness k grows unbounded, those conditions yield unbounded values of the gains. Motivated by the stability analysis of the impact Poincaré map in the perfectly rigid case (
), we propose an analysis that is independent of k. It enables us to conclude on global asymptotic convergence of the system's state towards the equilibrium point. This work can also be seen as the study of stability of a contact (force control) phase, taking into account the unilateral feature of the constraint. 相似文献
53.
Collapse is an essential operation for the manipulation of area features in digital data generalization. This operation can be categorized into two types: complete collapse and partial collapse. The former is composed of another two types: area-to-point and area-to-line collapse. In this paper, a set of algebraic models built upon the operators in mathematical morphology is described for the area-to-line collapse and partial collapse operations. For the area-to-line collapse operation, a modified skeleton algorithm is presented. For the partial collapse operation, a procedure is designed which consists of a set of operations, i.e., the skeletonization, separation of areal and linear parts, simplification of areas and an overlay operation. These models are tested using real map data sets. 相似文献
54.
实时全局地图构建是实现移动机器人智能化的关键;研究了一种基于全向视觉的移动机器人全局地图的实时构建方法.首先介绍了全向视觉的体系结构,然后对图像处理软件的相关模块,包括基于颜色的阈值分割、区域连通、特征提取和目标识别等进行了说明,最后通过坐标的转换实现全局地图的构建;实验结果表明,由于充分利用了全向视觉的特性,构建的全局地图准确性高、实时性好,完全能够满足移动机器人对环境建模的需要. 相似文献
55.
HUANG ZhiYong HE FaZhi CAI XianTao ZOU ZhengQin LIU Jing LIANG MingMing & CHEN XiaoComputer School Wuhan University Wuhan China 《中国科学:信息科学(英文版)》2011,(6):1207-1217
Most image retargeting algorithms rely heavily on valid saliency map detection to proceed. However, the inefficiency of high quality saliency map detection severely restricts the application of these image retargeting methods. In this paper, we propose a random algorithm for efficient context-aware saliency map detection. Our method is a multiple level saliency map detection algorithm that integrates multiple level coarse saliency maps into the resulting saliency map and selectively updates unreliable regio... 相似文献
56.
Seong-O Shim Author Vitae Author Vitae 《Pattern recognition》2010,43(10):3338-3347
Shape from focus (SFF) is a technique to estimate the depth and 3D shape of an object from a sequence of images obtained at different focus settings. In this paper, the SFF is presented as a combinatorial optimization problem. The proposed algorithm tries to find the combination of pixel frames which produces maximum focus measure computed over pixels lying on those frames. To reduce the high computational complexity, a local search method is proposed. After the estimate of the initial depth map solution of an object, the neighborhood is defined, and an intermediate image volume is generated from the neighborhood. The updated depth map solution is found from the intermediate image volume. This update process of the depth map solution continues until the amount of improvement is negligible. The results of the proposed SFF algorithm have shown significant improvements in both the accuracy of the depth map estimation and the computational complexity, with respect to the existing SFF methods. 相似文献
57.
张蕾 《艺术与设计.数码设计》2011,(3)
近些年来游戏产业空前发展,现已成为网络经济及文化娱乐业的重要组成部分。次时代游戏有其独特的形式与审美视觉价值被大家所认知。随着国外信息技术不断冲击国内游戏产业促使国内网游业集成了新技术,譬如次时代网游,国内知名的游戏公司久游首先利用了法线技术,运用到中国式的网游业中。其二是电脑硬件的提升有利于新技术的空前发展。文章粗浅总结一下次世代游戏单机的三维制作基本流程。 相似文献
58.
The use of the Internet in the daily activities of individuals and firms has become entrenched, and online shopping has become commonplace. However, debates about how online shopping recommendation mechanisms (OREMs) should be designed have not been completely resolved. The challenge with traditional online shopping recommendation mechanisms (TR-OREMs) is that they focus too much on quantitative factors. Thus, they ignore causal interrelationships with qualitative factors that are believed to significantly impact quantitative factors. Considering only quantitative factors and ignoring qualitative ones likely distorts the final recommendation results. Another problem with TR-OREMs is that they ignore the perceived psychological reactance of consumers against the recommended products. Such consumer reactance may be reduced when the causal interrelationships among all the quantitative and qualitative factors are analyzed and incorporated properly into the OREM. To overcome these problems, we propose a causal map – online shopping recommendation mechanisms (CM-OREMs) based on a causal map. We analyzed possible causal relationships among quantitative and qualitative factors and incorporated them in the recommendation process to reduce consumer reactance against the recommendation results. Furthermore, an elaboration likelihood model (ELM) was used to build hypotheses about how the online shopping behavior of consumers is affected by OREMs based on the proposed causal map. Specifically, the performance of the proposed OREM was empirically analyzed by gathering experiment data from qualified respondents who were asked to refer to the proposed OREM before making purchasing decisions via mobile phones. Statistical results showed that the proposed OREMs could enhance consumer decision satisfaction, decision confidence, and attitude toward the recommended products. It could also positively affect consumer purchasing intentions. The OREM had a greater effect on the high-reactance group of participants than on the low-reactance group as well as on a high-involvement product versus a low-involvement product. 相似文献
59.
针对常用的矿仓物位测量方式受粉尘和堆矿死角因素的影响而存在矿仓物位测量不准确的问题,提出了一种新型的矿仓物位测量方案。该方案选择重锤物位计消除粉尘干扰、采用多点布局求取均值的方法消除堆矿死角干扰。实际应用表明,该方案解决了粉尘和堆矿死角对物位测量的影响,降低了矿仓岗位人员的劳动强度。 相似文献
60.
文章分析了主题图的相关理论和传统文献组织方法优劣,论证了主题图在文献资源组织中的可行性,提出了基于主题图的文献资源组织模型及构建方法,引申了基于该模型的文献检索、主题导学、个性化资源推荐等应用研究。 相似文献