transform a state chart into a formal notation like
Petri Nets for analysis purpose.
Problem 4, Analyzing the System: Analysis of a
system, formal methods as theorem proving and
model checking are normally used.
By sharing the common characteristics and problems
between EVMS and ITS, we adapt the solutions
proposed in for ITS to EVMS. This approach, by
using UML and Petri net, can resolve some issues,
including:
- Modular architecture of the system
- Definition of components interfaces
- Definition of components behavior
- Assembling of the formal model
- Analysis.
The proposed approach is compatible with software
design; the methodology relies on UML and sticks
to the V-model for software life cycle. It introduces
a guideline to designers to achieve EVMS
specifications that is suitable for formal analysis and
verification. It also shows a way to enhance the use
of the achieved results from one modeling formalism
to the others. The interesting point is the full
automation of translations from UML models into
Symmetric Nets models in the framework of a
development tool as Eclipse Modeling Framework
(Budinsky et al., 2003), a basis for such an
implementation.
The case study represented in (Bonnefoi et
al.,2007). illustrates that we can use UML notation
and Petri net to specify an ITS that can be
implemented by a development tool as Eclipse.
However, there is no detail of the implementation,
neither transformation to code. For this issue,
Baobab (Bahar et al., 2009) might give us a good
example.
At a higher abstraction, EVMS naturally is a
kind of wireless sensor system (WSN). Baobab is
known as a model driven development (MDD)
framework for WSN applications. It provides a
generic meta-model (GMM) which is versatile
across different application domains including
EVMS. Baobab allows meta-model users to extend
GMM for defining their own domain-specific meta-
models and platform-specific meta-models.
Baobab’s model-to-code transformer type-checks
and validates a given application model and
generates application code in nesC (Gay et al., 2003)
for TinyOS (ww.tinyos.net/). Here, we do not intend
to go further in Baobab. We just introduce its meta-
models and models for WSN applications. In fact,
Baobab defined Generic Meta-model Elements
which represent sensor devices used in WSNs. All
sensor classes, representing a specific type of
sensors, extend from the base class Sensor. The most
common sensor types that can be used in a variety of
applications are defined in the generic meta-model.
For functional requirement specification, Baobab
also defines several elements to express the most
common functional aspects of WSNs. The functional
tasks can be modeled by using
ConditionalFunctional element of the GMM and
they can further be specialized into RepetitiveTask.
There are other tasks used to define the receipt of
data as DataReceipt and to request a waiting period
before another task can be called, as WaitingTask.
Sensing phenomena can be modeled with
SensingTask. This element retrieves the new-created
SensorData from the Sensor.
The non-functional requirements can be modeled
explicitly by means of NonFunctionalTask class in
the GMM. Some examples of non-functional tasks
defined in the GMM are: ClusterFormation for
dividing the network into clusters; ChangeSleepTime
for adjusting the sleep time to minimize energy.
Main classes defined in Baobab are represented in
Figure 9.
Baobab provides a domain specific modeling
language to specify WSNs and generate code of
such systems. Moreover, it also illustrated that we
can build the model with UML notation and
implements it by using a development tool as
Eclipse.
4 CONCLUSION
In this paper, we presented common characteristics
of EVMS that share characteristics of ITS. An
EVMS is a complex system based on sensor
networks, organized in hierarchy structure, including
sensor level, station level and monitoring center. An
EVMS consists of sensing devices distributed in a
wide area, which coordinate to produce meaningful
information. Sensor networks are usually wireless,
dynamic networks composed of a large number of
(possibly heterogeneous) sensors. These sensors
acquire pieces of information that may substantially
differ in content, resolution, and accuracy. It is
related to a large set of devices that are placed
outdoor, in the environment. Therefore, it needs to
do a lot of work on maintenance to ensure it works
properly. As a consequence, it is necessary to have
some appropriate approaches to facilitate the
specification, design, development and maintenance
of the system. In fact, it needs some formalism for
modeling, structuring the specification, and
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