Image Processing Reference
In-Depth Information
The SeNeTs Adaptation is a set of components which are added or exchanged to wrap the SNA.
Figure .b represents the SeNeTs Adaptation layer consisting of at least a logging component,
a controlling unit, a HAL, and an optional environment encapsulation module. These additional
components provide substantial and realistic test and controlling facilities.
An application composed of a SNA and SeNeTs Adaptation components is called sSeNeTs Appli-
cation (SeA). he SNA is not changed by added components. Generally, it is not necessary to adapt
the SNA to SeNeTs interfaces. However, supplementary macros can be added to interact with the
linked components.
A SeNeTs application runs as process of the host system. Due to the architecture of a SNA with
its own OS, the SeNeTs application runs autonomously without interaction to other processes of the
host system. At startup, the SeNeTs application opens a pipe to communicate with the AS. After
the test phase, all SeNeTs components can be removed easily by recompilation of all node applica-
tions. SeNeTs specific components and logging calls are automatically deactivated due to compiler
switches.
12.4.3.5 Environment Management
Sensor network applications require valid environment data, such as temperature or air pressure.
Under laboratory conditions, this information is not or partly not available. Therefore, environ-
ment data must be emulated. SeNeTs provides these environment data to the node application by
the environment emulation module (Figure .b). All environment emulation modules are con-
trolled by the environment management of the NS which contains all predefined or configured data
(Figure .). .).This data comprises positions of other nodes, distances to neighboring nodes, etc. If
required, other data types may be added. In the AS, the environment data cache module stores all
environment information required by each node application to reduce network traffic.
Optionally, position-based filtering is provided by the environment emulation component of
SeNeTs. Especially, if large topologies of sensor nodes should be emulated under small-sized lab-
oratory conditions, this filtering approach is essential. Suppose real and virtual positions of nodes
are known, a mapping from physical address to virtual address is feasible. A node application only
receives messages from nodes that are virtually in transmission range. All other messages are rejected
by the SeNeTs Adaptation components. This is accomplished by setting up a filter in the primary
communication channel.
One application scenario that illustrates position-based filtering is flood prevention. Here, sensor
nodes are deployed in sandbags, piled along a dike of hundreds of meters or even kilometers. hese
nodes measure the humidity and detect potential leakages. Testing this scenario under real-world
conditions is not practical and very expensive. However, the evaluation under real-world conditions
Application server
Host: rtl
Network server
Host: spice
Application
management
Command
execution
Network
management
Environment
data cache
Reachability list
Air pressure
Temperature
Environment
management
Logging
FIGURE .
Environment management in SeNeTs.
