slide1
Download
Skip this Video
Download Presentation
Ken C.K. Lee, Wang-Chien Lee, Hong Va Leong, Brandon Unger and Baihua Zheng, ICUIMC’09 Manu Shukla

Loading in 2 Seconds...

play fullscreen
1 / 11

Ken C.K. Lee, Wang-Chien Lee, Hong Va Leong, Brandon Unger and Baihua Zheng, ICUIMC’09 Manu Shukla - PowerPoint PPT Presentation


  • 79 Views
  • Uploaded on

Efficient Valid Scope Computation for Location-Dependent Spatial Queries in Mobile and Wireless Environments. Ken C.K. Lee, Wang-Chien Lee, Hong Va Leong, Brandon Unger and Baihua Zheng, ICUIMC’09 Manu Shukla August 2, 2009. Introduction.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Ken C.K. Lee, Wang-Chien Lee, Hong Va Leong, Brandon Unger and Baihua Zheng, ICUIMC’09 Manu Shukla' - aurek


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1

Efficient Valid Scope Computation for Location-Dependent Spatial Queries in Mobile and Wireless Environments

Ken C.K. Lee, Wang-Chien Lee, Hong Va Leong, Brandon Unger and Baihua Zheng, ICUIMC’09

Manu Shukla

August 2, 2009

introduction
Introduction
  • Mobile clients access information with respect to their location by submitting Location Dependent Spatial Queries (LDSQ) to Location-Based service servers
  • Due to limited mobile bandwidth and limited client battery life, frequent LSDQ submission must be avoided
  • Authors define the concept of valid-scope, a spatial area in which a set of LSDQs will retrieve exactly the same query results
  • Propose algorithms for valid scope computation for common LDSQs like range query and NN query
valid scope
Valid Scope
  • Determine a small and representative subset of non-result objects called “complementary objects” together with result objects
  • Use R-tree and best first search
valid scope for nn query
Valid Scope for NN Query
  • Objects that contribute the bisector as voronoi cell perimeter are added to complementary objects
  • Exploit the largest empty circle property
nn query
NN Query
  • Two steps to determine the NN query result and the valid scope of the result and one index lookup
    • First retrieve the nearest object
    • Examine non-result objects to refine valid scope
valid scope for range query
Valid Scope for Range Query
  • Minkowski region is defined as
  • Valid Scope is computed as an area equal to the intersection of the Minkowski regions of all result objects
range query
Range Query
  • Formula for valid scope can be defined as
experiments
Experiments
  • Compared with time-parameterized query method by Zhang et.al
  • Three data sets, real and two synthetic based on Gaussian and Uniform distribution
experiments1
Experiments
  • Overhead incurred by valid scope computations
conclusions
Conclusions
  • Valid for spatial queries in mobile environment where bandwidth and battery power in mobile devices are limited
  • Most calculations done on server and hence scalable
ad