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R. Khennaoui and N. Belala
(WFMS) for navigation applications in ubiquitous computing. In [7], a dynamic
context-aware access control for pervasive computing in enterprise environment
is proposed. However, [8,9] allow users to model their daily activities in the form
of workflow adaptable to context information. [10] proposes an approach to build
a flexible model to adapt business process based on context. In [11], both the
conceptual model and the workflow model are defined based on OWL.
Considering that the ambient systems manage our daily life such as smart
hospital, smart home, robots, etc., errors are critical regarding human life. Many
WFMS tools [12,13] exist and allow the modelling and verification of workflows.
However, mathematical approaches are proved to be more effective [14]. [15]
describes the workflow patterns in the formal specification language LOTOS
[16]. In addition, [17] proposes an approach to specify and verify the service
composition using LOTOS.
In this paper, we describe at first the workflow using Ag-LOTOS [18], a
formal specification model based on LOTOS. Ag-LOTOS is a formal technique
based on process algebra that allows to formally describe the workflow and to
verify properties on the model. Then, the contextual planning system of the
workflow (CPSw) [19] is built based on the semantics of Ag-LOTOS constrained
by contextual information. Unlike the previous work, our approach allows a
formal description of the context as pre- and post -condition in each state of all
the possible traces and adjust the changes dynamically. The proposed model can
be used in the verification process to check some contextual properties.
2 The Context-Aware Workflow Model
2.1 Ag-LOTOS for Workflows
Business Process Management (BPM) has been defined by van der Alast as
“a way to support business processes using methods, technique and software
to model, execute, control and analyze operational processes involving humans,
organizations, applications, documents or any other source of information” [20].
However, a workflow can be defined as “business process automation during
which documents, information or tasks are passed from one participant to
another according to a set of process rules” [20]. A workflow pattern [21] represents the abstraction of most frequent activities sequence, and are composed
when specifying new workflows.
In this section, we aim to use Ag-LOTOS [18] to improve workflow specification by including contextual information to each state of the workflow model,
and by modeling the ambient characteristics such as communication and mobility that cause the dynamic changes of the context.
Similar to LOTOS [16], Ag-LOTOS concurrency allows the modeling of parallel activities. The Ag-LOTOS subsystem support allows the composition of
workflow elements. Since Ag LOTOS is derived from LOTOS, we follow the procedure of mapping of the workflow patterns to LOTOS notation applied in [14]
and citecite6 to give the suitable definition of each operator in the workflow context. To specify activities in details, we can simply model them with Ag-LOTOS
sub-processes (hierarchy of processes). Note that Ag-LOTOS processes are used
R. Khennaoui and N. Belala
(WFMS) for navigation applications in ubiquitous computing. In [7], a dynamic
context-aware access control for pervasive computing in enterprise environment
is proposed. However, [8,9] allow users to model their daily activities in the form
of workflow adaptable to context information. [10] proposes an approach to build
a flexible model to adapt business process based on context. In [11], both the
conceptual model and the workflow model are defined based on OWL.
Considering that the ambient systems manage our daily life such as smart
hospital, smart home, robots, etc., errors are critical regarding human life. Many
WFMS tools [12,13] exist and allow the modelling and verification of workflows.
However, mathematical approaches are proved to be more effective [14]. [15]
describes the workflow patterns in the formal specification language LOTOS
[16]. In addition, [17] proposes an approach to specify and verify the service
composition using LOTOS.
In this paper, we describe at first the workflow using Ag-LOTOS [18], a
formal specification model based on LOTOS. Ag-LOTOS is a formal technique
based on process algebra that allows to formally describe the workflow and to
verify properties on the model. Then, the contextual planning system of the
workflow (CPSw) [19] is built based on the semantics of Ag-LOTOS constrained
by contextual information. Unlike the previous work, our approach allows a
formal description of the context as pre- and post -condition in each state of all
the possible traces and adjust the changes dynamically. The proposed model can
be used in the verification process to check some contextual properties.
2 The Context-Aware Workflow Model
2.1 Ag-LOTOS for Workflows
Business Process Management (BPM) has been defined by van der Alast as
“a way to support business processes using methods, technique and software
to model, execute, control and analyze operational processes involving humans,
organizations, applications, documents or any other source of information” [20].
However, a workflow can be defined as “business process automation during
which documents, information or tasks are passed from one participant to
another according to a set of process rules” [20]. A workflow pattern [21] represents the abstraction of most frequent activities sequence, and are composed
when specifying new workflows.
In this section, we aim to use Ag-LOTOS [18] to improve workflow specification by including contextual information to each state of the workflow model,
and by modeling the ambient characteristics such as communication and mobility that cause the dynamic changes of the context.
Similar to LOTOS [16], Ag-LOTOS concurrency allows the modeling of parallel activities. The Ag-LOTOS subsystem support allows the composition of
workflow elements. Since Ag LOTOS is derived from LOTOS, we follow the procedure of mapping of the workflow patterns to LOTOS notation applied in [14]
and citecite6 to give the suitable definition of each operator in the workflow context. To specify activities in details, we can simply model them with Ag-LOTOS
sub-processes (hierarchy of processes). Note that Ag-LOTOS processes are used