![](bgc.png)
over real-valued temporal constraints.
7 CONCLUDING REMARKS
We defined ACTNs as an extension of CSTNUs in
order to take into consideration users and authoriza-
tion constraints, and we used them to analyze the of-
ficial STEMI guidelines as a concrete example. We
similarly extended the execution semantics for CST-
NUs given in terms of RTEDs. After that, we pro-
vided an encoding from ACTNs to TGAs discussing
a few optimizations to speed up the model-checking
phase. We proved that our encoding is polynomial,
fully automated, and we also showed the correctness
(see the appendix). As a result, we provided a sound
and complete approach for the temporal WSP. As a fi-
nal contribution, we discussed our experimental eval-
uation using the UPPAAL-TIGA software tool. We
are currently implementing the encoder from ACTNs
into TGAs and an executor for executing the ACTN
following the synthesized strategy.
As future work we will investigate two main di-
rections, distinguished by the use, or not, of TGAs.
In the first case, we plan to address the workflow re-
siliency problem, which is a refinement of the WSP
when a subset of the authorized user may become
absent before or during the execution (again, a new
kind of uncertainty that needs a controllability ap-
proach). In the second, we plan to devise a network-
based constraint-propagation algorithm for ACTN
DC-checking. These algorithms might be more com-
plex but are typically faster than TCTL model check-
ing as they tighten the network by ruling out all im-
possible execution strategies.
Finally, we plan to provide a structured modeling
language for designing access-controlled workflows
to be mapped into ACTNs for the DC checking.
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APPENDIX
Theorem 1. Encoding ACTNs into TGAs has
polynomial-time complexity.
Proof. The main components having a role in the
complexity analysis of the encoding of an ACTN are:
Access Controlled Temporal Networks
129