Activity recognition and monitoring systems based on multi-sensor and
multi-device approaches are more and more popular to enhance events
production for scenario analysis. Underlying software and hardware
infrastructures can be considered as static (any change during the
overall recognition process), quasi-static (any change during two
reconfigurations of the process) or really dynamic (depending on dynamic
appearance and disappearance of numerous sensors and devices in the
scene, communicating with the system, during recognition process). In
this last case, we need to adapt partially and reactively the
application to the evolution of the environment, while preserving
invariants required for the validity of the recognition process. In
order to address such challenge our research try to federate the
inherent constraints of platform devoted to action recognition like SUP
with a service oriented middleware approach to deal with dynamic
evolutions of the infrastructure of the system. Recent results using a
Lightweight Component Architecture (SLCA) [1] to compose services for
device and Aspects of Assembly (AA) to adapt them in a reactive way [2]
present interesting prospects/ /to deal with multi-device and variable
systems. They provide a user-friendly separated description for
adaptations that shall be applied and composed at runtime as soon as the
corresponding required devices are present (in context-sensitive
security middleware layer for example [3]). They underline performances
and response times which allow to neglect the time of adaptation and
reconfiguration in comparison with delays for research and discovery of
services and management of appearance and disappearance of devices
[Revues]. However, although composition between these adaptations can
verify some properties, the use of black box components in the
composition model of SLCA doesn’t allow extracting a model of their
behavior. Thus, the existing approaches don't really succeed to ensure
that the usage contract of these components is not violated during
application adaptation. Only a formal analysis of the component behavior
models associated with a well sound modeling of composition operation
will allow us to secure the respect of the usage contracts.
In this axis, we propose to rely on a synchronous modeling of component
behavior and component assembly to allow the usage of model checking
techniques to formally validate services composition.
We began to consider this topic in 2008 through a collaborative action
(SynComp) between
Rainbow team at UNSA and Inria Pulsar team.
Within the Rainbow team, SLCA/AA experimental platform called WComp, is
dedicated to the reactive adaptation of applications in the domain of
ubiquitous computing.
During this collaboration, the management of concurrent access in WComp
has been
studied as a main source of disturbance for the invariant properties.. A
modeling of the behavior of components and of their accesses in a
synchronous model has been defined in WComp. This approach allows us to
benefit from model checking techniques to ensure that there are no
unpredictable states of WComp components on concurrent access.
This year, during his training, Vivien Fighiera (already involved in the
SynComp action),
has completed the theoretical work done in SynComp. He studies how prove
safety properties
regarding WComp component models relying on the NuSMV model checker.
This year, the collaboration between Rainbow and Pulsar has been
strengthened since
Jean Yves Tigli is researcher full time in Pulsar team since September,
in sabbatical year sponsored by Inria. We plan to extend the work
previously done in modeling also
the assembly of WComp components with a synchronous approach to allow
the usage of
model checking techniques to formally validate application design.
In order to obtain results based on experimental scenarios to evaluate
SynComp improvements for adaptive recognition process, we plan to
integrate SUP platform as a software services provider.
The SUP platform gathers a set of modules devoted to design
applications in the domain of activity recognition. WComp is aimed at
assembling services which evolve in a dynamic and heterogeneous
environment. Indeed, the services provided by SUP can be seen as complex
high-level services whose functionalities depend on the SUP treatments;
this latter dealing with the dynamic change of the environment.
Thus, considering SUP services as web services for devices for example,
the devices associated with SUP services will be discovered dynamically
by WComp and used with other heterogeneous devices.
References
[1] J.-Y. Tigli, S. Lavirotte, G. Rey, V. Hourdin, M.
Riveill,“Lightweight Service Oriented Architecture for Pervasive
Computing” IJCSI International Journal of Computer Science Issues, Vol.
4, No. 1, September 2009, ISSN (Online): 1694-0784, ISSN (Print): 1694-0814
[2] J.-Y. Tigli, S. Lavirotte, G. Rey, V. Hourdin, D. Cheung, E.
Callegari, M. Riveill “WComp middleware for ubiquitous computing:
Aspects and composite event-based Web services” in the journal Annals of
Telecommunications, Springer Paris editor, ISSN 0003-4347 (Print)
1958-9395 (Online), Vol. 64, No 3-4, March-April 2009.
[3] Vincent Hourdin, Jean-Yves Tigli, Stéphane Lavirotte, Gaëtan Rey et
Michel Riveill. « Context-Sensitive Authorization in Interaction
Patterns ». In the proceeedings of the ACM International Conference on
Mobile Technology, Applications and Systems (Mobility), Nice, France,
September 2009.