Research Objective:
- Design of spatial database query language for Battlefield decision support system.

Methodology:
- Object model for directions. E.g., North, Between, Left, 3 O’ Clock.
- Integrate directional data-types in industry-standard query language (SQL) and Spatial Library(OGIS).

Results:
- An algebra(value-domain, operators) for direction objects.
- Integration of algebra in commercial object-relational databases.

Significance:
- A major step towards simple “natural language” like query interface for battlaefield decision support systems.

Query: List the farm fields to the left of the lake which are suitable for tank movement ?

SELECT F.name, F.extent
FROM FarmField F, Lake L,Viewer V
WHERE V.left (F.extent, L.extent)
AND L.name = ‘Beech Lake’ AND F.soil-firmness > 5;

Note: Left is a viewer-based “direction” predicate.

Orientation-based Direction Query Processing

Classical Strategies:
- Based on Range query strategy

Limitations:
- May lead to large unnecessary I/O and CPU cost
- Need to know world boundary and calculate the intersection of boundary and direction region
- Post Filter step is needed even for MBR objects

Our Approach:
- Open shape based strategy(OSS)

Open Shape based Strategy(OSS)

Basic idea:
- Model direction region as an open shape
- Use actual direction region as a filter

Advantages:
- Improve filtering efficiency by eliminating false hits
- Reduce unnecessary I/O and CPU cost
- Eliminate post Filter step for MBR objects
- Do not need to have knowledge of world boundary

Experimental Evaluations:
- Consistently outperforms classical range query strategy both in I/O and CPU.

Contact

X.Liu (IBM Research)
S. Shekhar (Minnesota)
S.Chawla (Sydney)