An increasing number of location-based service
providers are taking the advantage of cloud computing by outsourcing
their Point of Interest (POI) datasets and query services
to third-party cloud service providers (CSPs), which answer various
location-based queries from users on their behalf. A critical
security challenge is to ensure the integrity and completeness of
any query result returned by CSPs. As an important type of
queries, a location-based skyline query (LBSQ) asks for the POIs
not dominated by any other POI with respect to a given query
position, i.e., no POI is both closer to the query position and more
preferable with respect to a given numeric attribute. While there
have been several recent attempts on authenticating outsourced
LBSQ, none of them support the shortest path distance that is
preferable to the Euclidian distance in metropolitan areas. In this
paper, we tackle this open challenge by introducing AuthSkySP,
a novel scheme for authenticating outsourced LBSQ under the
shortest path distance, which allows the user to verify the integrity
and completeness of any LBSQ result returned by an untrusted
CSP. We confirm the effectiveness and efficiency of our proposed
solution via detailed experimental studies using both real and
synthetic datasets.
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In-Path Oracles for Road Networks
Many spatial applications benefit from the fast answering to a seemingly simple spatial query: “Is a point of interest (POI) ‘in-path’ to the shortest path between a source and a destination?” In this context, an in-path POI is one that is either on the shortest path or can be reached within a bounded yet small detour from the shortest path. The fast answering of the in-path queries is contingent on being able to determine without having to actually compute the shortest paths during runtime. Thus, this requires a precomputation solution. The key contribution of the paper is the development of an in-path oracle that is based on precomputation of which pairs of sources and destinations are in-path with respect to the given POI. For a given road network with n nodes and m POIs, an O(m×n)-sized oracle is envisioned based on the reduction of the well-separated pairs (WSP) decomposition of the road network. Furthermore, an oracle can be indexed in a database using a B-tree that can answer queries at very high throughput. Experimental results on the real road network POI dataset illustrate the superiority of this technique compared to a baseline algorithm. The proposed approach can answer ≈ 1.5 million in-path queries per second compared to a few hundred per second using a suitable baseline approach.
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- NSF-PAR ID:
- 10447860
- Date Published:
- Journal Name:
- ISPRS International Journal of Geo-Information
- Volume:
- 12
- Issue:
- 7
- ISSN:
- 2220-9964
- Page Range / eLocation ID:
- 277
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3390/ijgi12070277
