In this demo, we introduce CRISTAL (Collection of ResourcecentrIc Supporting Tools And Languages), a tool suite aimed at improving the human resource management capabilities of current Business Process Management Systems (BPMSs), covering the design and enactment phases of the business process (BP) life cycle. The central element is Resource Assignment Language (RAL), a Domain Speci c Language (DSL) for specifying resource assignments in process models. RAL's strong analysis capabilities enable the automated resolution of resource assignment expressions both (i) at design time, serving for post-design analysis to nd and correct potential problems prior to execution, and (ii) at run time, in order to execute the BP in an existing BPMS considering the RAL assignments for resource allocation. The resource assignments can be directly modelled in a Business Process Modelling Notation (BPMN) diagram, or speci ed by means of a RACI matrix. In the latter case, CRISTAL can take all the RACI information automatically and introduce it into a resource-unaware BPMN model at any moment, resulting in a RACI-aware BP model (and, thus, a resource-aware BP model).
RAL is a DSL speci cally developed to express resource assignments for the
activities of a BP [
We provided RAL with formal semantics based on Description Logics (DLs)
in order to be able to automatically solve RAL expressions. It also enabled us to
bene t from operations implemented in DL reasoners to analyse BPs in terms of
how resources are being managed. RAL's semantics now cover both the design
time [
As explained in [
Furthermore, RAL can also be used together with RACI matrices to specify
resource assignments in a BP model. RACI matrices constitute an alternative
for enhancing the management of human resources in an organization,
providing detailed information about the degree of involvement of the members of the
company in the activities carried out within it [
CRISTAL is composed of several tools, to be named RACI2BPMN, DT RAL Solver and RT RAL Solver, which facilitate the de nition and analysis of resources in BP models. These tools can be used separately or sequentially. Figure 1 provides an overview of the system, in which the tools are represented in rounded rectangles, their inputs and outputs are represented by documents linked with dashed arrows, and the possible interconnection between tools is done by using solid arrows. One possible way to use CRISTAL's tools is the following.
We can use Oryx [
BPMN Editor
(Oryx) BPMN w/o resources
BPMN w/ resources BPMS (Activiti) Resource Modeller
RACI model
RACI2BPMN Users
Activiti Explorer Process Modeller Organizational
model DT RAL Solver
RT RAL
Solver Execution
History any resource assignments. Then, with CRISTAL's RACI Editor we can build a RACI matrix with the responsibility assignments we aim to apply to the process activities. In order to generate accurate resource assignments for the process, the RACI matrix may need to be extended with some binding information. CRISTAL's RACI Editor is a Web application that allows the de nition of both the RACI matrix and the binding information. It is currently under development.
With these inputs, the RACI2BPMN tool can automatically turn the resourceunaware process model into a RACI-aware BPMN model, i.e. it contains the assignments from the RACI matrix and the binding information. The resourcerelated information in the model is expressed with RAL. The resulting BP model can be opened in any editor that supports BPMN 2.0 (e.g. Oryx), so both the process model and the resource assignments can be modi ed as desired.
The next tool to be executed may be DT RAL Solver, which allows us to automatically analyse the RAL expressions associated to the activities of a RALaware BP model. Among other operations, this tool automatically calculates the set of potential performers for each activity in the process model. To do so, the tool must receive the OWL description of an organizational model together with the RAL-aware BP model.
Finally, RAL-aware BP models can also be opened in an open-source BPMS called Activiti1, in which we have previously integrated the RT RAL Solver tool. The goal of this tool is to automatically solve the RAL expressions at run time. Then, the proper activities are automatically o ered to the potential performers resulting from the assignments at run time, to proceed with the allocation of the tasks to speci c resources. The execution history is stored in execution logs.
The low-level description of CRISTAL's architecture can be found at www. isa.us.es/cristal/. 3
The DT RAL Solver tool was developed in 2011, as a prototype to demonstrate
how DL reasoners could be used to automatically solve RAL expressions at
design time [
The RACI2BPMN tool has been recently developed from research results
on how to combine BPs and RACI matrices, given that the resource-related
information provided by the matrices is greater than the information that today's
BP modelling notations allow to specify [
For the former, a few instructions can be found at http://www.isa.us.es/
cristal/. The latter is totally transparent to the user of the BPMS.
6. Extensibility capabilities. More analysis operations over RAL
assignments can be easily added by composing operations already implemented
by current DL reasoners (e.g. HermiT, or Pellet), as stated in [
However, CRISTAL has also some limitations. The e ciency of complex and/or compound resource assignments may not be good enough due to the inference operations the DL reasoner has to perform. 3.1
Signi cance to the BPM Field CRISTAL o ers innovative features with respect to the (human) resource management capabilities provided by current BPM notations and systems.
First, to the best of our knowledge, RACI2BPMN is the rst tool focused on the automated introduction of RACI information in a process model, generating RACI-aware BP models that can be executed with no need of changes.
Second, regarding RAL, the RAL Solver tool provides BP modelling languages with a more expressive mechanism to assign resources to tasks. Furthermore, as far as we know, RAL is the rst resource assignment language that o ers automated analysis capabilities at design time that are built in the language itself. As for run time, it is a fact that most of the BPMSs existing at present have resource assignment mechanisms based basically on assigning users or groups of users (sometimes also roles) to the BP activities (e.g. Activiti, jBPM, Intalio|BPMS). Other tools such as YAWL are more expressive because they are supported by a more powerful organizational meta model. However, YAWL does not rely on a speci c language for resource assignments, and uses ad-hoc mechanisms to assign resources and resolve the assignments instead. Therefore, we believe RAL outperforms the current scope, both at design time and at run time. 4
Further information about RAL, the descriptions of the tools, user instructions, and downloadable example les can be found at http://www.isa.us. es/cristal. The source code and executable les are available on demand. CRISTAL can be extended in di erent directions referring to resource management in BPs. Some future work consists of adding the proper functionality to detect at design time potential allocation problems that can arise at run time, and which are derived from the control ow of the process, e.g. empty sets of potential performers due to the de nition of a Binding of Duties (BoD) constraint between two activities that belong to di erent branches of an XOR gateway.
Another possible line to extend the tool is about dealing with data together with resources, e.g. to automatically generate Access Control Lists (ACLs) from a resource and data-aware BP model.
The optimization of RAL Analyser is also part of planned work.
We want to thank ISA group's development team for the support provided, especially Ana Belen Sanchez and Edelia Garc a.