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31.
Robot Pose Estimation in Unknown Environments by Matching 2D Range Scans 总被引:14,自引:0,他引:14
A mobile robot exploring an unknown environment has no absolute frame of reference for its position, other than features it detects through its sensors. Using distinguishable landmarks is one possible approach, but it requires solving the object recognition problem. In particular, when the robot uses two-dimensional laser range scans for localization, it is difficult to accurately detect and localize landmarks in the environment (such as corners and occlusions) from the range scans.In this paper, we develop two new iterative algorithms to register a range scan to a previous scan so as to compute relative robot positions in an unknown environment, that avoid the above problems. The first algorithm is based on matching data points with tangent directions in two scans and minimizing a distance function in order to solve the displacement between the scans. The second algorithm establishes correspondences between points in the two scans and then solves the point-to-point least-squares problem to compute the relative pose of the two scans. Our methods work in curved environments and can handle partial occlusions by rejecting outliers. 相似文献
32.
Ibrahim H. Osman Nicos Christofides 《International Transactions in Operational Research》1994,1(3):317-336
The capacitated clustering problem (CCP) is the problem in which a given set of weighted objects is to be partitioned into clusters so that the total weight of objects in each cluster is less than a given value (cluster ‘capacity’). The objective is to minimize the total scatter of objects from the ‘centre’ of the cluster to which they have been allocated. A simple constructive heuristic, a R-interchange generation mechanism, a hybrid simulated annealing (SA) and tabu search (TS) algorithm which has computationally desirable features using a new non-monotonic cooling schedule, are developed. A classification of the existing SA cooling schedules is presented. The effects on the final solution quality of the initial solutions, the cooling schedule parameters and the neighbourhood search strategies are investigated. Computational results on randomly generated problems with size ranging from 50 to 100 customers indicate that the hybrid SA/TS algorithm out-performs previous simulated annealing algorithms, a simple tabu search and local descent algorithms. 相似文献
33.
本文首先根据文本中各个字符的颜色相似的特性,确定已知文本块的文本的颜色,利用文本的颜色信息二值化文本图像以得到文本块中的字符数、字符的尺寸和间距;其次,根据视频图像的大小和视频的播放速度确定搜索窗口的大小,并利用文本的运动信息来预测搜索窗口的位置;第三,根据在相邻两帧中具有相同内容文本的颜色相似的特性,提出了一个可以解决脉冲噪声和部分缺损或遮挡问题的稳健匹配准则来跟踪文本块;最后,确定跟踪输出的文本的颜色、尺寸和运动方式。本文方法可以很好地跟踪平移、缩小或放大、旋转、淡入淡出和部分被遮挡的水平或倾斜排列的文本,并且可以记录文本平移、旋转和缩放的速度。 相似文献
34.
In this paper we develop and compare several heuristic methods for solving the general two-dimensional cutting stock problem.
We follow the Gilmore-Gomory column generation scheme in which at each iteration a new cutting pattern is obtained as the
solution of a subproblem on one stock sheet. For solving this subproblem, in addition to classical dynamic programming, we
have developed three heuristic procedures of increasing complexity, based on GRASP and Tabu Search techniques, producing solutions
differing in quality and in time requirements. In order to obtain integer solutions from the fractional solutions of the Gilmore-Gomory
process, we compare three rounding procedures, rounding up, truncated branch and bound and the solution of a residual problem.
We have coded and tested all the combinations of algorithms and rounding procedures. The computational results obtained on
a set of randomly generated test problems show their relative efficiency and allow the potential user to choose from among
them, according to the available computing time.
Rceived: January 9, 2001 / Accepted: December 10, 2001 相似文献
35.
36.
本详细描述了移动IP的工作过程,并介绍了移动IP的隧道技术和IPSec,最后对移动IP技术中存在几个热点问题进行了讨论。 相似文献
37.
The search for good lineal, or depth-first, spanning trees is an important aspect in the implementation of a wide assortment of graph algorithms. We consider the complexity of findingoptimal lineal spanning trees under various notions of optimality. In particular, we show that several natural problems, such as constructing a shortest or a tallest lineal tree, are NP-hard. We also address the issue of polynomial-time, near-optimization strategies for these difficult problems, showing that efficient absolute approximation algorithms cannot exist unlessP = NP.This author's research was supported in part by the Sandia University Research Program and by the National Science Foundation under Grant M IP-8603879.This author's research was supported in part by the National Science Foundation under Grants ECS-8403859 and MIP-8603879. 相似文献
38.
Matthew Huntbach 《International journal of parallel programming》1991,20(4):299-314
The concurrent logic languages, of which Parlog is one, have been promoted as a new generation of software languages specifically designed for parallel programming. This paper investigates their application to a search problem commonly used as an illustration of artificial intelligence techniques, the 8-puzzle. It notes that programs written in the concurrent logic languages which do not pay attention to the parallelism can fall into two possible traps: either there is little real parallelism in them due to data dependencies, or there is too much parallelism and any practical architecture will be overwhelmed. A solution which controls the parallelism using user-defined priorities is proposed. This solution has the advantage of being architecture-independent. 相似文献
39.
Multiple forms of a symbol-digit substitution task were used to provide a componential analysis of age differences in coding task performance. The results demonstrated age differences in feature encoding, memory, and visual search. A 2nd experiment was conducted with young adults to investigate a sensory deficit as a locus of age differences. The spatial contrast sensitivity deficit of older adults was simulated on forms by applying a digital filter. Persons in the age-simulated contrast condition performed worse than those in the normal contrast condition. The stimulus degradation effect was linked to visual search speed. The study illustrates the utility of componential analysis and offers direct support for the hypothesis that sensory deficits affect performance on tasks used to assess intelligence (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
40.
Two experiments examined the disruption of feature-based selection in triple-conjunction search at multiple target transfers. In Experiment 1, after 10 training sessions, a new target possessing previous distractor features was introduced. This produced disruption in RT and fixation number, but no disruption in feature-based selection. Specifically, there was a tendency to fixate objects sharing the target's contrast polarity and shape and this did not change even upon transfer to the new target. In Experiment 2, 30 training sessions were provided with three target transfers. At the first transfer, the results replicated Experiment 1. Subsequent transfers did not produce disruption on any measure. These findings are discussed in terms of strength theory, Guided Search, rule-based approaches to perceptual learning, and the area activation model. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献