1Chapter 0 Modeling Positional Uncertainty in Buffer Analysis

Abstract This paper presents design considerations for vibration assisted compliant assembly involving peg-in-hole insertion. We propose a feasible parts mating assembly model, based on the positional uncertainty and tolerance of an assembly task. For an infeasible task, whose tolerance set does not contain the uncertainty set, it is proposed to introduce a relative motion between the two mating parts, so as to enlarge the task tolerance relative to its uncertainty. A specific type of such motion, viz vibration in two orthogonal directions, is studied in detail. The amplitudes and frequencies of vibrations are determined for given tolerance, uncertainty, and other assembly parameters. A numerical procedure is devised to select the ratio of the two orthogonal vibration frequencies, for minimum search time of parts engagement. Criteria on suitable compliances for assembly are proposed, with consideration of insertion failure.

Download Full-text

HiBuffer: Buffer Analysis of 10-Million-Scale Spatial Data in Real Time

ISPRS International Journal of Geo-Information ◽

10.3390/ijgi7120467 ◽

2018 ◽

Vol 7 (12) ◽

pp. 467 ◽

Cited By ~ 3

Author(s):

Mengyu Ma ◽

Ye Wu ◽

Wenze Luo ◽

Luo Chen ◽

Jun Li ◽

...

Keyword(s):

Real Time ◽

Spatial Data ◽

High Performance ◽

Large Scale ◽

Computation Time ◽

Buffer Analysis ◽

Data Volume ◽

Time Buffer ◽

Real World Datasets ◽

Spatial Indexes

Buffer analysis, a fundamental function in a geographic information system (GIS), identifies areas by the surrounding geographic features within a given distance. Real-time buffer analysis for large-scale spatial data remains a challenging problem since the computational scales of conventional data-oriented methods expand rapidly with increasing data volume. In this paper, we introduce HiBuffer, a visualization-oriented model for real-time buffer analysis. An efficient buffer generation method is proposed which introduces spatial indexes and a corresponding query strategy. Buffer results are organized into a tile-pyramid structure to enable stepless zooming. Moreover, a fully optimized hybrid parallel processing architecture is proposed for the real-time buffer analysis of large-scale spatial data. Experiments using real-world datasets show that our approach can reduce computation time by up to several orders of magnitude while preserving superior visualization effects. Additional experiments were conducted to analyze the influence of spatial data density, buffer radius, and request rate on HiBuffer performance, and the results demonstrate the adaptability and stability of HiBuffer. The parallel scalability of HiBuffer was also tested, showing that HiBuffer achieves high performance of parallel acceleration. Experimental results verify that HiBuffer is capable of handling 10-million-scale data.

Download Full-text