Enabling Time-Aware Process Support
with the ATAPIS Toolset
Andreas Lanz and Manfred Reichert
Institute of Databases and Information Systems, Ulm University, Germany
{andreas.lanz,manfred.reichert}@uni-ulm.de
Abstract.
The proper handling of temporal constraints is crucial for
business processes in many application domains. Contemporary process-
aware information systems (PAIS), however, lack a sophisticated support
of time-aware processes. First of all, at design time it should be possible
to specify the temporal constraints of a business process. In turn, this
should be accompanied by checking the respective time-aware process
schema for inconsistencies that may emerge due to hidden interdepen-
dencies among the temporal constraints. The latter is crucial to enable a
robust and error-free execution of the time-aware process schema. At run
time, corresponding process instances need to be monitored for violations
of their temporal constraints. This demo paper presents the ATAPIS
Toolset for modeling and enacting time-aware processes. The toolset is
based on AristaFlow BPM Suite—an industrial-strength process manage-
ment system. The ATAPIS Toolset enables process engineers to correctly
specify and implement time-aware processes. Further, time-aware process
instances can be efficiently executed, whilst monitoring their temporal con-
straints. Altogether, the ATAPIS Toolset covers the temporal
perspective
of processes at design as well as run time in a comprehensive way.
1 Introduction
Time is a crucial factor regarding business process support [
8
]. In many ap-
plication domains (e.g., patient treatment, automotive engineering) the proper
handling of temporal constraints is vital in order to successfully execute and com-
plete processes [
2
,
5
,
8
]. Contemporary process-aware information systems (PAIS),
however, lack a sophisticated support of time-aware processes [
8
]. To remedy this
drawback, the proper integration of temporal constraints with both the design
and run-time components of a PAIS has been identified as a key challenge in the
development of next generation process management technology [2,5,7].
The toolset presented in this demonstration has been developed in the AT-
APIS
1
project. The major goal of this project is to provide a comprehensive
framework enabling the specification, enactment and monitoring of time-aware
processes in adaptive PAIS. The ATAPIS Toolset
2
allows specifying time-aware
1Adaptive Time- And Process-aware Information System
2A screencast is available on dbis.info/atapis
2 Andreas Lanz and Manfred Reichert
process schemas as well as checking their temporal consistency at design time.
Furthermore, at run time, related time-aware process instances may be created,
executed, and continuously checked for temporal constraint violations.
The components presented in this tool demonstration allow modeling tem-
poral constraints as first class citizens of a process schema. In particular, the
toolset covers most of the time patterns introduced in [
8
]. Empirical evidence
from case studies has confirmed that these patterns are required for modeling the
temporal perspective of processes in a variety of domains. Furthermore, the demo
shows how the ATAPIS Toolset enables soundness and consistency checks of
time-aware process schemas to guarantee for a robust and correct process instance
execution. Finally, different notions of temporal consistency (e.g., weak / dynamic
consistency, controllability) are supported. Note that a discussion on further
related work is omitted for lack of space. Interested readers are refereed to [
8
,
7
].
2 The ATAPIS Toolset
The ATAPIS Toolset is implemented based on the AristaFlow BPM Suite, an
industrial-strength process management system that exploits advanced process
support features we developed in previous research projects [
4
]. In particular,
AristaFlow provides an open API in combination with a modular, service-oriented
system design [
6
]. The latter allows us to extend AristaFlow with functions re-
quired for the specification and execution of time-aware processes.
2.1 Specifying Time-Aware Process Schemas
Fig. 1 depicts the process editor of the ATAPIS Toolset. It is based on the
AristaFlow Process Template Editor, which we enhance with capabilities and
language elements required to capture and implement fundamental time pat-
terns [
8
]. Currently, the ATAPIS Toolset covers the following time patterns: Time
Lags between two activities (TP1), Durations (TP2), Fixed Date Elements (TP4),
Schedule Restricted Elements (TP5), Time-Dependent Variability (TP8), and
Cyclic Elements (TP9).
In order to enable time lags between two activities (TP1) and cyclic elements
(TP9) we extend AristaFlow’s process modeling language [
10
] with time edges.
In the process editor, such a time edge between two activities is visualized by
a dashed line (cf. Fig. 1). In accordance with TP1, a time edge may be added
between arbitrary activities that can be conjointly executed in the context of a
process instance (i.e., a time edge must not be added between activities from
exclusive branches). Furthermore, a time edge is configured in respect to the
represented restriction (i.e., minimum and/or maximum time distance) and the
kind of time lag (i.e., start-start, start-end, end-start, or end-end). The concrete
configuration settings are reflected by a label attached to the time edge; e.g., the
label
E
[0
h,
2
h
]
S
which is attached to the time edge between activities
prepare
patient and perform treatment (cf. Fig. 1), describes a time lag with a mini-
mum time distance of 0
hours
and a maximum time distance of 2
hours
between
the end (E) of the former activity and the start (S) of the latter.
Enabling Time-Aware Process Support with the ATAPIS Toolset 3
Time Edge
Properties Editor
Activity Duration
Fixed Date Element
Fig. 1. ATAPIS process editor enabling the modeling of temporal constraints
In turn, time patterns restricting a particular activity (or the process) (i.e.,
Duration,Fixed Date Element, and Schedule Restricted Element) may be con-
figured with the corresponding properties editor. In Fig. 1, for example, activity
prepare treatment
is selected and the properties editor is shown in the lower
part. In the upper section of this editor, the duration of the activity must be
specified. In ATAPIS, durations are specified through three values [
7
], which
can be interpreted as follows: usually, activity durations are contingent, i.e., it is
possible to set up a duration range for any activity, the contingent minimum and
maximum duration, however, the PAIS becomes aware of the effective activity
duration only after its completion. Hence, the duration must not be restricted by
the PAIS. In practice, however, activity durations usually represent worst case
estimates; i.e., most durations may be restricted to some extend; we call this the
flexible maximum duration. For better usability, the duration of the activity is
visualized on the right side section of the properties editor.
In the lower section of the properties editor (cf. Fig. 1), two fixed date elements
are specified for activity
perform treatment
. The one restricting the earliest
start date of the activity retrieves its value from data element
date
. In turn, the
fixed date element restricting the latest start date is set relatively to (i.e., 30
minutes after) the one on the earliest start date of the activity.
Similarly a schedule restricted element may be specified for any activity. In
turn, this constraint is based on a language for representing collections of temporal
intervals [
9
] (e.g., formula [1-5]/days:during:weeks represents the first 5 days of
each week; i.e., Monday–Friday).
4 Andreas Lanz and Manfred Reichert
Time Model View
Fig. 2. Checking temporal consistency of a process schema
2.2 Checking Temporal Consistency
A time-aware process schema is enacted by performing its activities in the specified
order, while obeying the specified temporal constraints. Generally, a time-aware
process schema is denoted as temporally consistent if it is possible to perform
all execution paths without violating the temporal constraints involved [
1
]. Note
that temporal consistency of a time-aware process schema and its instances
constitutes a fundamental prerequisite for a robust and error-free execution [
1
,
5
].
For any PAIS supporting time-aware processes, therefore, a crucial task is to
check temporal consistency of the process schema at design time as well as to
monitor and ensure temporal consistency of process instances during run time.
This is challenging since temporal constraints might interact with each other
resulting in complex (hidden) interdependencies. For example, assume that a
time lag is added between activities
prepare patient
and
inform patient
in
the process schema depicted in Fig. 1 (cf. Fig. 2). Assume further that the time
lag specifies that activity
prepare patient
must be completed at least one hour
before
inform patient
may be started. In this scenario, —although not directly
obvious—the process schema can never be enacted without violating at least one
of its constraints, i.e., the process schema is temporally inconsistent (cf. Fig. 2).
To check whether a particular process schema is temporally consistent, AT-
APIS maps it to a specific time model (cf. Fig. 2). The latter allows us to capture
the complex interdependencies between constraints, which are not explicit in pro-
cess models. To support various consistency notions, the ATAPIS Toolset provides
different implementations of the time model; e.g., using conditional simple tempo-
ral networks [
11
] to check for weak or dynamic consistency or conditional simple
Enabling Time-Aware Process Support with the ATAPIS Toolset 5
temporal networks with uncertainty [
3
] to check for dynamic controllability—a
more restricted form of temporal consistency. Particularly, we choose these models
since they allow us to exploit and reuse correct and sound checking algorithms
for well founded models representing temporal constraints.
When analyzing the temporal perspective of a process schema one may also
view the corresponding time model including any hidden temporal constraints
resulting from interdependencies of the specified temporal constraints (cf. Fig. 2).
To support a thorough analysis of the temporal perspective of a process schema
(e.g., to analyze the impact of a particular date for a fixed date element), we
additionally provide editing capabilities for these time models.
3 Conclusion
The demonstration presents the ATAPIS Toolset and its components. It allows
creating time-aware process schemas based on a well-founded modeling language.
Further, it allows checking time-aware process schemas for temporal consistency
in order to ensure their executability. We are currently investigating the impact
of process change operations on time-aware processes and are implementing them
in ATAPIS. Further, we are integrating temporal features with the run-time
environment of the AristaFlow BPM Suite.
References
1.
Bettini, C., Wang, X.S., Jajodia, S.: Temporal reasoning in workflow systems. Distrib
Para Dat 11(3), 269–306 (2002)
2.
Combi, C., Gozzi, M., Posenato, R., Pozzi, G.: Conceptual modeling of flexible
temporal workflows. TAAS 7(2), 19:1–19:29 (2012)
3.
Combi, C., Hunsberger, L., Posenato, R.: An algorithm for checking the dynamic
controllability of a conditional simple temporal network with uncertainty. In: Proc
ICAART’13 (2013)
4.
Dadam, P., Reichert, M.: The ADEPT project: A decade of research and development
for robust and flexible process support - challenges and achievements. Computer
Science - R&D 22(2), 81–97 (2009)
5.
Eder, J., Euthimios, P., Pozewaunig, H., Rabinovich, M.: Time management in
workflow systems. In: Proc BIS’99. pp. 265–280 (1999)
6.
Lanz, A., Kreher, U., Reichert, M., Dadam, P.: Enabling process support for advanced
applications with the AristaFlow BPM Suite. In: BPM’10 Demo (2010)
7.
Lanz, A., Posenato, R., Combi, C., Reichert, M.: Controllability of time-aware
processes at run time. In: Proc CoopIS’13. pp. 39–56 (2013)
8.
Lanz, A., Weber, B., Reichert, M.: Time patterns for process-aware information
systems. Req Eng 19(2), 113–141 (2014)
9.
Leban, B., McDonald, D., Forster, D.: A representation for collections of temporal
intervals. In: Proc AAAI’86. pp. 367–371 (1986)
10.
Reichert, M., Dadam, P.: ADEPTflex – supporting dynamic changes of workflows
without losing control. J Intell Inf Syst 10(2), 93–129 (1998)
11.
Tsamardinos, I., Vidal, T., Pollack, M.: CTP: A new constraint-based formalism
for conditional, temporal planning. Constraints 8(4), 365–388 (2003)
