Database Reference
In-Depth Information
Metadata Collector
1
Over-the-Air Programmer
2
Query Execution Plan
3
Fig. 4.
Node Images in Flash Memory
Fig. 5.
Lifecycle Steps
deployment. The lifecycle of a query involves the steps depicted in Fig. 5 and
described below:
Metadata Collection.
Nodes run the
Metadata Collector
program which gen-
erates a description of the WSN topology (e.g., expected energy transmission
energy between nodes, based on average package loss) for use by the
SNEE
compiler. This program is based on the
Collection Tree Protocol
3
,andworks
by sending routing table entries of each node to the gateway. When this com-
pletes, the nodes reboot into the
Over-the-Air Programmer
(OTAP).
Query Compilation.
The user poses a query and Quality-of-Service expec-
tations, which is compiled using the
SNEE
Query Compiler
intoaquery
execution plan based on the metadata that was collected in the previous
step. Query compilation is described in detail in [GBG
+
11].
Code Generation/Compilation.
The Sensor Network Connectivity Bridge
translates the query execution plan into a
nesC
program for each node, each
of which is compiled into a binary image.
3
This is an implementation of the tree formation protocol described in
