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On the Formal Semantics of the Extended
Compliance Rule Graph
David Knuplesch1, Manfred Reichert1, Linh Thao Ly1, Akhil Kumar2, and
Stefanie Rinderle-Ma3
1Institute of Databases and Information Systems, Ulm University, Germany
david.knuplesch,manfred.reichert,[email protected]
2Smeal College of Business, Pennsylvania State University, PA, USA
3Faculty of Computer Science, University of Vienna, Austria
Abstract. A fundamental challenge for any process-aware information
system is to ensure compliance of modeled and executed business pro-
cesses with imposed compliance rules stemming from guidelines, stan-
dards and laws. Such compliance rules usually refer to multiple process
perspectives including control flow, data, time, and resources as well
as interactions with business partners. On one hand, compliance rules
should be comprehensible for domain experts who must define and ap-
ply them. On the other, compliance rules should have precise semantics
such that they can be automatically processed. In this context, providing
a visual compliance rule language, which hides formal details from rule
designers, is crucial in order to enable an intuitive way of modeling. So
far, visual compliance rule languages have focused on the control flow
perspective, but lack adequate support for the other perspectives. To
remedy this drawback, this report introduces the extended Compliance
Rule Graph language and its formal semantics.
Keywords: business process compliance, compliance rule graphs, busi-
ness process modeling, business intelligence, formal semantics
1 Introduction
During the last decade, numerous approaches for ensuring the correctness of
business processes have been discussed [2–5]. Most of them focus on syntac-
tical correctness and process model soundness (e.g., absence of deadlocks and
lifelocks). However, business processes must also comply with semantic rules
stemming from domain-specific requirements such as corporate standards, le-
gal regulations, guidelines or best practices [6, 7]. Summarized under the no-
tion of business process compliance, existing approaches have mostly considered
This work was done within the research project C3Pro funded by the German Re-
search Foundation (DFG), Project number: RE 1402/2-1, and the Austrian Science
Fund (FWF) under project number: I743. Parts of this technical report will be pub-
lished in [1].
2 Knuplesch, Reichert, Ly, Kumar, Rinderle-Ma
compliance issues related to the control flow perspective of single processes. In
turn, only a few approaches consider the data, resource, and time perspectives
in this context, although they are crucial as well [8–11]. Furthermore, cross-
organizational scenarios characterized by interacting and collaborating business
processes of various parties have not been properly considered so far [12]. In this
context, compliance requirements need to be specified for both local and global
processes as well. Note that this requires to consider the data, resource, and time
perspectives as well as interactions between business partners (i.e. messages ex-
changed) as well. As examples consider the compliance rules in Table 1, which
are imposed on a cross-organizational process scenario involving the two business
partners reseller and manufacturer. In particular, as shown by the highlighted
terms in Table 1, compliance rules may refer to the data, time, and resource per-
spectives of business processes as well as to interactions with business partners.
Compliance rule c1refers to the interactions between a reseller and manufac-
turer (request and reply) after a particular point in time (3rd January, 2013) as
well as the maximum time distance between them (within three days). In turn,
the data perspective of compliance rules is emphasized by compliance rule c2
of the manufacturer. It forbids changing an order after having started the cor-
responding production task. Compliance rule c3combines the interaction, time,
and data perspectives. Finally, compliance rule c4introduces the resource per-
spective (member of the order processing department and another member of
the same department with supervisor status). In addition, c4considers the data
perspective (e.g. new customer and total amount greater than e5,000) and the
time perspective (at most three days). Particularly, c4shows that the different
perspectives might be relevant for the same rule and hence must not be consid-
ered in an isolated manner.
When comparing c4and c2with c1and c3, one can observe two different view-
points: c4and c2are expressed from the viewpoint of the manufacturer (i.e.,
local view), whereas c1and c3reflect a global view. Note that such distinction
Table 1: Examples of compliance rules for order-to-delivery processes
c1Any request sent from the reseller to the manufacturer after January 3rd, 2013
should be replied by the manufacturer within three days.
c2After starting the production related to a particular order, the latter must not
be changed anymore.
c3When the manufacturer sends a bill with an amount lower than e5,000 to the
reseller, the latter must make the payment within 7 days.
c4After receiving a production request message from the reseller, which refers to
anew customer and has a total amount greater than e5,000, the solvency of
this customer must be checked by a member of the order processing department.
Based on the result of this check, another member of the same department with
supervisor status must approve the request. Finally, the approval result must be
sent to the reseller at most three days after receiving the original request.
On the Formal Semantics of the Extended Compliance Rule Graph 3
between local and global views is common to cross-organizational collaboration
scenarios not only in the context of process compliance [12, 13]. For example,
BPMN 2.0 provides collaboration and choreography diagrams to express these
different viewpoints.
Several approaches for formally capturing compliance requirements at different
abstraction levels (e.g., temporal logics [14]) exist. In particular, they also enable
the automatic verification of the conformance of business processes with respec-
tive compliance rules. As the use of formal languages for specifying compliance
rules would be too intricate, rule patterns hiding formal detail from rule mod-
elers have been proposed [9, 11]. Furthermore, a few approaches also consider
more advanced issues like, for example, the use of data conditions in the context
of compliance requirements. However, existing approaches are usually restricted
to a specific subset of rule patterns. In turn, languages employing visual nota-
tions, like the compliance rule graph approach [15] or BPSL [16], combine an
intuitive notation with the advantages of a formal language. However, the meta-
analyses and case studies, we conducted in domains like higher education [17],
medicine [18–21] and automotive engineering [22, 23], have revealed that these
visual compliance rule languages still lack support for the time, data, and re-
source perspective of business processes and do not consider cross-organizational
scenarios with interacting partners [12]. Overall, the following fundamental re-
quirements for visual compliance rule languages need to be considered:
In addition to the control flow perspective, the data, resource and time per-
spectives of compliance requirements must be properly captured.
To not only consider process orchestrations, but cross-organizational scenar-
ios as well, it becomes necessary to integrate the interaction perspective with
compliance rule languages as well.
To provide tool support for both the modeling and verification of compliance
rules, both their syntax and semantics must be formalized.
To cope with the discussed shortcomings, this report introduces the extended
Compliance Rule Graph (eCRG) and its formal semantics. The eCRG builds on
the Compliance Rule Graph (CRG) language developed in previous work [15, 24],
but additionally comprises elements enabling the visual modeling of compliance
rules with the support of the process, data, time, and resource perspectives. Fur-
thermore, we introduce concepts that allow defining compliance rules in respect
to message flows and partner interactions; i.e., the eCRG language is able to
specify compliance requirements for cross-organizational process scenarios (i.e.
processes choreographies). For defining the formal semantics of the eCRG, we
provide a transformation into FOL formula. Note that the latter can be evaluated
over process traces to a posteriori verify the compliance of business processes.
Altogether, the eCRG allows capturing compliance requirements at an abstract
level, while enabling the specification of verifiable compliance rules in the context
of cross-organizational scenarios, including the process, data, time, and resource
perspectives.
4 Knuplesch, Reichert, Ly, Kumar, Rinderle-Ma
The remainder of this report is structured as follows: Section 2 discusses re-
lated work. Section 3 introduces the extended Compliance Rule Graph (eCRG).
The formal semantics of the eCRG language is specified in Section 4, whereas
Section 5 provides a pattern-based evaluation. Finally, Section 6 concludes the
report and provides an outlook on future research.
2 Related Work
During the last years the interaction, time, resource, and data perspectives have
been considered in business process modeling in addition to the control flow
perspective (e.g., [25–33]).
The integration of business process compliance throughout the entire process
lifecycle has been discussed in [24, 34–36]; [37] examined compliance issues in
the context of cross-organizational processes developing a logic-based formalism
for describing the semantics of normative specifications as well as compliance
checking procedures. This approach allows modeling business obligations regu-
lating the execution of business processes. In turn, [38] introduced a semantic
layer that interprets process instances according to an independently designed
set of internal controls. Furthermore, there exist approaches using semantic an-
notations to ensure compliance [39]. An approach for checking the compliance of
process models against semantic constraints as well as for ensuring the validity
of process change operations based on Mixed-Integer Programming formulation
is proposed in [40]. It introduces the notions of degree of compliance,validity
of change operations, and compliance by compensation. Further, [9] uses align-
ments to detect compliance violations in process logs. To verify whether compli-
ance rules are fulfilled by process models at design time, many approaches apply
model checking techniques [14, 16, 41–44]; some of them address the data and
time perspectives as well. In order ensure compliability and global compliance
of cross-organizational processes, where partners only provide restricted views
on their local processes, [45, 46] apply model checking as well. Other approaches
for verifying compliance apply the notion of semantic congruence [47] or use
petri-nets [48] and consider the data and time perspectives as well.
The approach described in [41, 49] for visually modeling compliance considers the
control flow and data perspectives. It is based on linear temporal logic (LTL),
which allows modeling the control flow perspective based on operators like next,
eventually,always, and until. Other visual approaches for compliance rule mod-
eling [15, 16, 50] focus on control flow and partially the data perspective, but
ignore the other perspectives mentioned.
3 Extended Compliance Rule Graphs
This section introduces extended Compliance Rule Graphs (eCRG) a visual
notation for compliance rule modeling covering the process, interaction, time,
resource, and data perspectives. Secion 3.1 introduces fundamentals of CRGs.
Its extensions are introduced stepwise in Sections 3.2–3.6.
On the Formal Semantics of the Extended Compliance Rule Graph 5
3.1 Fundamentals of Compliance Rule Graphs
The compliance rule graph (CRG) language [15, 24] allows visually modeling
compliance rules whose semantics is defined over event traces. More precisely, a
CRG is an acyclic graph consisting of an antecedence pattern as well as at least
one related consequence pattern. Both patterns are modeled using occurrence and
absence nodes, which indicate the occurrence or absence of events (e.g., related
of the execution of a particular task). Edges between such nodes indicate control
flow dependencies. As illustrated in Fig. 1, a trace is considered as compliant
with a CRG iff for each match of the antecedence pattern there is at least
one corresponding match of every consequence pattern. Furthermore, a trace is
considered as trivially compliant iff there is no match of the antecedence pattern.
For example, the CRG from Fig. 1 expresses that for each Bnot preceded by
an A, there must occur a D, which is not preceded by any Calso preceding the
corresponding B.
C D C D
Antecedence pattern Consequence pattern
only match < E, D, F, G, B >
only match < D, F, C, E, B >
no match ( < A, B, C, E, D > )
only match < C, F, B, G, E >
1st match < B, C, D, E, B >
2nd match< B, C, D, E, B >
< E, D, F, G, B >
< D, F, C, E, B > (C is after D!)
-
no match (missing D)
< B, C, D, E, B >
no match ( < B, C, D, E, B > )
A B A B A B
< E, D, F, G, B >
< D, F, C, E, B >
< A, B, C, E, D >
< C, F, B, G, E >
< B, C, D, E, B >
compliant
compliant
trivially compliant
violation
violation
Antecedence
Occurrence
Antecedence
Absence
Consequence
Absence
Consequence
Occurrence
CRG
Fig. 1: CRG example and semantics over execution traces
In the following sections, we introduce the extended Compliance Rule Graph
(eCRG) language, which is based on CRGs. In addition to using nodes and
connectors (i.e., edges), eCRG allows for attachments. The latter represent con-
straints to the nodes or edges they are attached to. Furthermore, an eCRG may
contain instance nodes representing particular instances, which exist indepen-
dently from the respective rule (e.g. a particular employee Mr. Smith, date 3rd
January 2013, or role supervisor). Accordingly, instance nodes are neither part
of the antecedence nor the consequence pattern.
3.2 Process Perspective
We first consider the process (i.e., control flow) perspective. The eCRG elements
for modeling the process (i.e. control flow) perspective of compliance rules are in-
troduced in Fig. 2. Since the extensions are based on the CRG language, there ex-
ist four different task elements, i.e., antecedence occurrence,antecedence absence,
consequence occurrence, and consequence absence tasks. These allow expressing
whether or not particular tasks must be executed. In addition, two different
kinds of sequence flow connectors are provided that may be used to constrain
6 Knuplesch, Reichert, Ly, Kumar, Rinderle-Ma
Performer
Task
Task
Performer
Task
Tasks Nodes Local View
Antecedence Consequence
OccurenceAbsence
Task Task
Task
Tasks Nodes Interaction View
Antecedence Consequence
OccurenceAbsence
Performer
Task
Task
Performer
Sequence Exclusion
Antecedence Connectors
Sequence Exclusion
Consequence Connectors
Alternative
Alternative
Fig. 2: eCRG elements of the process perspective
the execution sequence of tasks. Note that the absence of sequence flow indicates
a parallel flow. To clearly distinguish between start-start,start-end,end-start,
and end-end constraints on the execution sequence of tasks, sequence flow edges
are either connected to the right or left border of a task node. Furthermore,
exclusive connectors allow modeling mutual excluding tasks. Alternative con-
nectors, in turn, express that at least one of the connected tasks must occur.
Note that exclusive as well as alternative connectors may only connect nodes
that are either part of the antecedence or the consequence pattern.
Fig. 4A shows an example of a start-start constraint on the execution sequence
of tasks. It depicts the process perspective of compliance rule c2from Table 1
that disallows executing task change order after task production is started.
3.3 Interaction Perspective
The interaction perspective of business processes is crucial in cross-organizational
scenarios [51, 13]. It covers constraints on the messages exchanged between busi-
ness pratners and the interaction view of the eCRG meta-model. Message ex-
changes are expressed in terms of particular nodes that reflect the events of
sending and receiving a message. In turn, a message flow denotes the depen-
dency between the events representing the sending and receiving of a particular
message (cf. Fig. 3).
Antecedence Consequence Antecedence Consequence
Sender
Message
Receiver
Sender
Message
Receiver
Sender
Message
Receiver
Sender
Message
Receiver
Antecedence Consequence
OccurenceAbsence
Antecedence
Message Flow
Connector
Consequence
Message Flow
Connector
Interaction Nodes Interaction ViewMessage Nodes Local View
Sender
Receiver Message
Message
Sender
Message
Receiver
Message
Sender
Receiver Message
Message
Sender
Message
Receiver
Message
ReceiveSend
OccurenceAbsence
Fig. 3: eCRG elements of the interaction perspective
On the Formal Semantics of the Extended Compliance Rule Graph 7
Production
Change
Order
Reseller
Reseller
Reply
Check
Solvency Approval
Request
A B
Fig. 4: Local view on c2and c4with process and interaction perspectives
Reseller
Request
Manufacturer
Manufacturer
Reply
Reseller
Manufacturer
Billing
Information
Reseller
Payment
Reseller
BA
Fig. 5: Interaction view on c1and c3with process and interaction perspectives
In Fig. 4B, the elements from Fig. 3 are used to model the process and inter-
action perspective of compliance rule c4. This rule requires that after receiving
message request from a reseller, a solvency check must be performed first. Then,
a decision about approval has to be made before replying the request. Although
the rule modeled in Fig. 4B considers the interaction perspective, using the two
message nodes request and reply, it still represents the view of a particular busi-
ness partner on its local business processes. We refer to this traditional point
of view as the local view of a compliance rule. However, when considering the
compliance rules c1and c3from Table 1, one can easily discover a global point
of view on cross-organizational processes and related interactions (i.e., the mes-
sages exchanged) that corresponds to the BPMN 2.0 choreography diagram. In
this interaction view, interaction nodes (cf. Fig. 3) are used to denote the ex-
change of a message between two business partners. Since the interaction view
spans multiple business partners, task nodes may be annotated with the the
business partner responsible (cf. Fig. 2).
Fig. 5A provides an interaction view on compliance rule c1from Table 1: After
the reseller sends a request to the manufacturer, eventually, the manufacturer
must reply. Furthermore, Fig. 5B provides an interaction view on compliance rule
c3from Table 1. This rule requires that the reseller must perform task payment
after having received billing information from the manufacturer.
3.4 Time Perspective
The time perspective of a business process deals with temporal constraints that
need to be obeyed by instances of the process [28, 29].
Having a closer look on the original definition of compliance rules c1and c3
from Table 1, it becomes clear that the eCRGs from Figs. 5A and 5B do not
fully specify them yet. In particular, the time distances between the interactions
and tasks have not been modeled. Fig. 6 provides elements for modeling points
in time and time conditions in compliance rules. The latter may be attached to
task nodes as well as sequence or message flow connectors to either constrain the
duration of a task or the time distance between tasks, messages or points in time.
Additionally, time distance connectors are introduced that must be attached
8 Knuplesch, Reichert, Ly, Kumar, Rinderle-Ma
Occurence
Anteced.
Points
in Time
Antecedence
Consequence
Time
Conditions
>2d
>2d
Anteced. Sequence
Distance Connector
Consequ. Sequence
Distance Connector
Absence
March 23th
2013
Particular
Point in TimeConsequ.
Fig. 6: eCRG elements of the time perspective
Reseller
Request
Manufacturer
Manufacturer
Reply
Reseller
< 3 days
Jan 3rd
2013
Manufacturer
Billing
Information
Reseller
Payment
Reseller
< 7days
A B
Fig. 7: Interaction view on c1and c3with process, interaction and time perspec-
tives
with a time condition. Respective time distance connectors and related time
conditions then allow constraining the time distance between tasks, messages or
points in time without implying a particular sequence.
Fig. 7A combines the interaction and time perspectives of compliance rule c1.
This visual representation of c1covers exactly the semantics of the compliance
rule described in Table 1. In Fig. 7B, the interaction and time perspectives of
c3are provided. This compliance rule requires that at most seven days after the
manufacturer sends billing information to the reseller, the latter must perform
task payment.
3.5 Resource Perspective
The resource perspective covers the different kinds of human resources as well
as their inter-relations [25, 52]. Further, it allows constraining the assignment of
resources to tasks. In the context of our work, we consider resources like staff
member,role,group, and organizational unit as well as their relations to tasks.
Furthermore, we support resource conditions and relations among resources (cf.
Fig. 8). Similar to task nodes, resource nodes may be part of the antecedence
or consequence patterns. Alternatively, they may represent a particular resource
instance (e.g. staff member Mr. Smith, or role supervisor). In turn, resource
conditions may constrain resource nodes. Furthermore, the performing relation
indicates the performer of a task. Finally, resource relation connectors express
relations between resources. Note that the resource perspective can be easily
extended with other kinds of resources if required.
Fig. 9 combines the process, interaction, time, and resource perspectives of com-
pliance rule c4. This rule requires that at least three days after receiving a request
of the reseller, a replay must be sent to him. Before sending this reply, first of
all, task solvency check must be performed by a staff member assigned to the
particular organizational unit order processing department. Following this task,
another staff member of the same department with supervisor status (i.e., role)
must decide whether to grant approval before sending the reply.
On the Formal Semantics of the Extended Compliance Rule Graph 9
< value
> value
Antecedence
Consequence
Data/Resource Conditions
Data
Object
Data
Object
Data Nodes
AntecedenceConsequence
Antecedence
Data Flow Connector
Consequence
Data Flow Connector
Group Organizational
Unit
Staff
Member
Role
Group Organizational
Unit
Staff
Member
Role
Resource Nodes
Antecedence
Performing and
Relation Connector
Consequence
Performing and
Relation Connector
( )
( )
Data Container
Data Container
Requests
Request
from
Mrs Ly
Particular
Resources
Quality
Managers
Dept. Information
Systems
Mr Knup
Computer
Scientist
Fig. 8: eCRG elements of the resource and data perspectives
Fig. 9: Local view on c4with process, interaction, time, and resource perspectives
3.6 Data Perspective
The data perspective of business processes covers the data objects processed
as well as the data flow between the tasks of the process [32, 53, 33]. Fig. 8
introduces eCRG elements for modeling data containers and data objects as well
as connectors representing data flow. Thereby, data containers refer to process
data elements or global data stores. By contrast, data objects refer to particular
data values and object instances. Similar to resource nodes, data nodes may be
part of the antecedence or consequence pattern, or represent a particular data
container or data object (e.g., data container student credit points, document 1st
order from Mr. Smith). Furthermore, data flow defines which process tasks read
or write which data objects or data container. To constrain data container, data
objects, and data flow, data conditions may be attached. Finally, data relation
connectors may be used either to compare different data objects or to constrain
the value of data containers at particular points in time.
Figs. 10A-C show the visual modeling of compliance rules c2,c3, and c4covering
the data perspective as well as the other perspectives discussed. Note that each
of the depicted eCRG covers the informal semantics described in Table 1.
10 Knuplesch, Reichert, Ly, Kumar, Rinderle-Ma
Customer
data
Supervisor
Reseller
Request
Reseller
Reply
amount > 5000
Check
Solvency Approval
< 3 days
Request Approval
Result
new customer?
Order
Processing
Department
assigned
Solvency
result
is
assigned
Production
Change
Order
Order
Manufacturer
Billing
Information
Reseller
Payment
Reseller
< 7days
Bill
amount < 5000
A
B
C
Fig. 10: Local view on c2and interaction view on c3and c4, considering the
process, interaction, time, resource, and data perspectives
4 Formal Semantics of the eCRG
In the previous section, we have only informally described eCRG semantics. In
order to enable automated compliance checking of process logs against eCRG,
however, an unambiguous formal semantics is required. For this purpose, this sec-
tion provides a transformation from eCRG to first-order predicate logic (FOL),
which defines how to interpret and evaluate an eCRG over process logs.
How this transformation can be accomplished is described in the following. First,
Section 4.1 introduces sets representing fundamental business process concepts
(e.g., tasks types, resources, or data values). Second, process logs are formally
defined as set of predicates in Section 4.2. Third, Section 4.3 provides a set-based
formal description of an eCRG. Fourth, Section 4.4 defines the transformation
translating the eCRG into logic formula based on the defined predicates.
4.1 Environmental Sets and Concepts
The eCRG language relates to different perspectives of business processes, i.e.,
the process, time, data, resource, and interaction perspectives. The formalization
of the eCRG language requires a formal definition of theses fundamental concepts
defining the process environment in Def. 1 as follows:
Definition 1 (Process Environment).
The environment of a business process comprises the following sets:
Tis the set of task types
Mis set of message types
Tis the discrete and ordered set of points in time
R=RSRRRGRUis the set of resources, with RSbeing the set of staff members,
RRbeing the set of roles, RGbeing the set of groups, RUbeing the set of business units
and departments.
Dset of data containers, Pset of activity and message parameters,
set of data values and objects (e.g. 5,1.345, color red, document-A, report-123, . . . ),
ITset of task instance identifiers, and
IMset of message instance identifier.
On the Formal Semantics of the Extended Compliance Rule Graph 11
1
Further, based on the definition of the environment, we introduce the following sets of conditions
and relations for time, data and resources:
CT{contcontTB}is the set of time conditions,
CD{condcondB}is the set of data conditions,
CR{conrconrRB}is the set of resource conditions,
RT{reltreltT2B}is the set of time relations,
RD{reldreld2B}is the set of data relations, and
RR{relrrelrR2B}is the set of resource relations.
InStaff RRis a resource relation and InStaff(r, s)indicates that staff member
sbelongs or is assigned to resource r. Furthermore, we do not explicitly distin-
guish between time conditions and time relations, since each time condition cont
constitutes a time relation relcontwith
relcont(t1, t2)cont(∣t1t2∣).
4.2 Process Logs
A common way to capture the execution of a business process is to store exe-
cution events in process logs and traces [2]. Usually, the latter contain multiple
information about the tasks executed, messages exchanged, or data objects ac-
cessed. However, not all logged information is of interest for evaluating whether
or not a particular process instance complies with a given compliance rule. In-
dependent from the concrete format of a process log, we introduce a set of
predicates describing its relevant information in Def. 2. Obviously, the values of
these predicates can be easily derived by processing a concrete process log:
Definition 2 (Execution Log Entries/Predicates).
Let T,M,T,R,D,IT,IMbe defined as in Def. 1. Then, predicate
Start(t, i, tt)expresses that task iITof type tt Tis started at tT.
End(t, i, tt)expresses that task iITof type tt Tis completed at tT.
Perform(i, s)expresses that task iITwas performed by the staff member sRS.
Receive(t, i, mt, b)expresses that message iIMof type mt Mis received from business
partner bBat tT.
Send(t, i, mt, b)expresses that message iIMof type mt Mis sent to business partner
bBat tT.
Parameter(i, p, v)expresses that execution parameter pPof task or message iITIM
has parameter value v.
Write(t, i, p, v, d)expresses that task or message iITIMwrites value vto data
container dDvia output parameter pPat tT.
Read(t, i, p, v, d)expresses that task or message iITIMreads value vto data
container dDvia input parameter pPat tT.
Based on predicate Write, we define predicate Value:
Value(t0, o, v)t1Tt1<t0Write(t1,,, v, o)t2t1<t2<t0Write(t2,,,, o)
Note that we use dots () as wildcards, i.e.:
Write(t1,,,, o)x1, x2, x3Write(t1, x1, x2, x3, o)
12 Knuplesch, Reichert, Ly, Kumar, Rinderle-Ma
4.3 Formal Description of eCRG
We now introduce a set-based formal description of the eCRG. Since the latter
constitutes a graph, it consists of nodes (e.g. task nodes) and edges (e.g. sequence
flow edge). Furthermore, the eCRG nodes and edges may have attachments that
specify additional constraints. Thus, we can roughly define an eCRG as specified
in Def. 3:
Definition 3 (eCRG).
An eCRG Ψis a graph Ψ=(N, E, ), where
Nis the set of nodes,
Eis the set of edges, and
is the set of attachments to nodes and edges.
As described in Section 3, each element of an eCRG (i.e., node, edge, or attach-
ment) can either be element of the antecedence pattern (A) or the consequence
pattern (C) or be a particular instance (I) (e.g., a particular employee Mr. Smith,
date 3rd January 2013, or role supervisor). In the cases of nodes, the antecedence
pattern is partitioned into the antecedence occurrence pattern (AO) and the an-
tecedence absence pattern (AA), while the consequence pattern is partitioned
into the consequence occurrence pattern (CO) and the consequence absence pat-
tern (CA). Before formally introducing these pattern classes in Def. 7, we first
define the various elements of an eCRG (i.e., nodes, edges and attachments) in
more detail.
Nodes. The most fundamental elements of the eCRG are nodes. According to
the different compliance perspectives the set of nodes Ncan be partitioned into
nodes corresponding to tasks, receiving and sending messages, points in time,
data containers, data objects, and resources as follows:
Definition 4 (Nodes of an eCRG).
Let Nbe the set of nodes of an eCRG Ψ=(N, E, ). Then, Ncan be partitioned as follows:
N=TMRMSPDOR, where
Tis the set of task nodes,
MR/MSis the set of receiving/sending message nodes,
Pis the set of nodes representing points in time,
Dis the set of data container nodes,
Ois the set of data object nodes.
R=RSRGRRRUare the sets of resource nodes for staff members, groups, roles, and
organizational units.
In the following, we use TSTEinstead of Tin order to distinguish whether
edges are connected to the left and right side of task nodes. Thereby, TSis
the left side, i.e. it corresponds to the start of a task, whereas TEis the right
side corresponding to completion end of a task. Furthermore, we introduce the
function sTTS(eTTE) to get the start (end) of a task node, and
function tTSTETfor the opposite direction. Function type (TT)
(MM)assigns to each task and message node the associated task or message
On the Formal Semantics of the Extended Compliance Rule Graph 13
type. bp (MRMS)Bdenotes the business partner that sends or receives a
message. Finally, T MP =TMRMSPNis the set of a all task, message,
and points in time nodes, whereas DR =DORNcomprises all data
container, data object, and resource nodes.
We can partition the set of nodes and each of its subsets into distinct sets of
particular instance nodes, antecedence nodes, and absence nodes as well as into
particular instance nodes, antecedence occurrence nodes, antecedence absence
nodes, consequence occurrence nodes, and consequence absence nodes. We use
the exponents I,A,C,AO,AA,CO and CA to indicate the corresponding subset.
Further, the exponent Idenotes that all nodes are considered except particular
instance ones.
Edges. The nodes of an eCRG can be connected through a wide range of edges
indicating relations and correlations between these nodes. In particular, the set
of edges can be partitioned into distinct subsets (cf. Def. 5). The latter contain
edges for sequence flow, message flow, and distance in time. Other edge subsets
refer to read/write data flow from/to data containers or data objects as well as
to the performers of tasks and relations among data objects or resources. Finally,
the two last subsets contain edges specifying correlations between conditions to
data containers and the particular points in time, when these conditions are
evaluated:
Definition 5 (Edges of an eCRG).
We consider Eas the set of edges of an eCRG Ψ=(N, E, ). Then, Ecan be partitioned as
follows:
E=# »
sf # »
mf # »
tde # »
wdfc # »
rdfc # »
wdfo # »
rdfo # »
pfm #»
rr
dr # »
dcec # »
dceo, where
# »
sf (TSTEMSMRP)2×RTis the set of sequence flow edges including a time
condition,
# »
mf MS×MRis the set of message flow edges,
# »
tde (TMRMSP)2×CTis the set of time distance edges including a time condition,
# »
wdfc (TMRMS)×(P{})×Dis the set of data flow edges writing to a data container,
# »
rdfc D×(TMRMS)×(P{}) is the set of data flow edges reading from a data
container,
# »
wdfo (TMRMS)×(P{})×Ois the set of data flow edges writing a data object,
# »
rdfo O×(TMRMS)×(P{}) is the set of data flow edges reading a data object,
# »
pfm T×Ris the set of performing relation edges denoting the performer of a task,
#»
rr R2×RRis the set of resource relation edges,
dr O×O×RDis the set of data relation edges,
# »
dcec (TSTEMRMSP)×D×CDis the set of data condition edges constraining a
data container at a particular point in time by a data condition,
# »
dceo (TSTEMRMSP)×D×Ois the set of data condition edges requiring a data
container to contain a data object at a particular point in time.
Further, src EN(tgt EN) is a function that maps each edge to its
source node (target node), whereas nd EN, e nd(e)={src(e), tgt(e)} is
a function that maps each edge to the set containing its source and target node.
Edges are either part of the antecedence or the consequence pattern. Hence, we
can further partition the set of edges and each of its subsets into antecedence and
14 Knuplesch, Reichert, Ly, Kumar, Rinderle-Ma
consequence edges. We use exponents Aand Cto indicate when only considering
the particular subset.
According to the definition of
# »
sf, each sequence flow requires a time relation.
Thereby, if the graphical representation does not provide a time relation, we
just assume the time condition to be T2, i.e., true for each input. Further an
antecedence edge with a consequence time condition is interpreted as two edges:
an antecedence edge without a time condition and a consequence edge with the
respective time condition.
Attachments. Nodes and edges of an eCRG may be refined by attachments. In
turn, these attachments constitute additional conditions for the respective node
or edge. In particular, the set of attachments can be partitioned into distinct
subsets. The latter refer to different data conditions constraining data flow or
parameters of tasks or messages. Other attachments express time conditions that
constrain the duration of tasks or resource conditions that constrain resources:
Definition 6 (Attachments of an eCRG).
We consider as the set of attachments of an eCRG Ψ=(N, E, ). Then, can be partitioned
as follows:
=dcp doc dfc dfo td rc, where
dcp (TM)×P×CDattaches a task or message node with a data condition on a particular
parameter,
doc O×CDattaches data object nodes with a data condition,
dfc (# »
wdfc # »
rdfc # »
wdfo # »
rdfo)×CDattaches data flow edges with a data condition,
dfo (# »
wdfc# »
rdfc)×Oattaches data flow edges from/to a data container with a data object
serving as placeholder for the value of the data flow,
td T×RTattaches task nodes with a time relation that constraints the duration of the
task, and
rc R×CRattaches resource nodes with a resource condition.
Further, at NEis a function mapping each attachment to the node or
edge it corresponds to. Attachments are either part of the antecedence or the
consequence pattern. Consequently, we can partition the set of attachments and
each of its subsets into antecedence and consequence attachments. Again, we use
exponents Aand Cwhen solely referring to the respective subset.
Pattern Classes. As mentioned in Section 3, nodes, edges, and attachments can
be classified as elements of the instance, the antecedence, or the consequence
pattern. In the context of nodes, the antecedence and consequence pattern are
further partitioned into the antecedence occurrence and the antecedence absence
pattern as well as the consequence occurrence and the consequence absence pat-
tern. Def. 7 formally introduces the pattern classes and transfers the finer classi-
fication to edges and attachments (i.e., the classification into antecedence occur-
rence, antecedence absence, consequence occurrence, and consequence absence
patterns). For this purpose, we consider pattern classes of the nodes connected
by an edge as well as the pattern class of the element an attachment corresponds
to.
On the Formal Semantics of the Extended Compliance Rule Graph 15
Definition 7 (Classes of an eCRG).
Let Ψ=(N, E, )be an eCRG. Then:
I=NIis the instance pattern,
A=NAO NAA EAAis the antecedence pattern,
C=NCO NCA ECCis the consequence pattern,
EAO ={eEAnd(e)NAO}is the set of antecedence occurrence edges,
EAA ={eEAnd(e)NAA nd(e)NAO }is the set of antecedence absence edges,
ECO ={eECnd(e)NCnd(e)(NCO NAO )} is the set of consequence occurrence
edges,
ECA ={eECnd(e)NCA nd(e)(NCO NAO )}is the set of consequence
absence edges,
AO ={aAat(a)NAO EAO}is the set of antecedence occurrence attachments,
AA ={aAat(a)NAA EAA}is the set of antecedence absence attachments,
CO ={aCat(a)NAO EAO NCO ECO }is the set of consequence occurrence
attachments,
CA ={aCat(a)NCA ECA}is the set of consequence absence attachments,
AO =NAO EAO AO is the antecedence occurrence pattern,
AA =NAA EAA AA is the antecedence absence pattern,
CO =NCO ECO CO is the consequence occurrence pattern,
CA =NCA ECA CA is the consequence absence pattern, and
C={I, AO, AA, CO, CA}is the set of pattern classes.
4.4 Transformation of eCRG
After having defined a formal representation of the process environment, process
logs and compliance rules, we are able to define the semantics of a particular
compliance rule. For this purpose, we transform the eCRG into a first-order pred-
icate logic formula in this subsection. Instead of nodes, edges and attachments,
the resulting logic formula comprises variables derived from the eCRG elements.
However, note that the set of variables is not isomorphic to the sets of nodes
and edges. Thus, Def. 8 introduces the variables required, before describing the
transformation in detail. In this context, we use relation to indicate the set
of values a variable may take.
Definition 8 (Variables).
Let Ψ=(N, E, )be an eCRG, then:
νt
xTcorresponds for each xTSTEMRMSPto the variable for either the point in
time of the start (end) xof a task node, the point of receiving (sending) a message related
to message node x, the time related to a point in time node x, or the particular point in
time of xiff xPIis a particular point in time instance node.
νi
xITIMcorresponds for each xTMRMSto the the variable for the instance
identifier of a task or message node x.
νp
xRScorresponds for each xTto the variable for the performing staff member of a
task node x.
16 Knuplesch, Reichert, Ly, Kumar, Rinderle-Ma
2
νr
xRcorresponds for each xRSRGRRRUto the variable for the related resource
of a resource node xor to the particular resource of x, iff xRIrefers to a particular
resource instance.
νdc
xDcorresponds for each xDto the variable for the associated data container of data
container node xor to the particular data container of x, iff xDIrefers to particular
data container instance.
νdo
xcorresponds for each xOto the variable for the data object related to a data
object node xor to the particular data object x, iff xOIrefers to a particular data object
instance.
νdv
xcorresponds for each x# »
wdfo # »
rdfo # »
wdfa # »
rdfa dcp to the variable for the
value of a data flow edge xor the value of the parameter of an attached data condition x.
Furthermore, we define the following sets:
Vt={νt
xxTSTEMRMSP}corresponds to the set of all variables for points in
time,
Vi={νi
xxTMRMS}corresponds to the set of all variables for instance identifiers,
Vp={νp
xxRS}corresponds to the set of all variables for performing staff members,
Vr={νr
xxRSRGRRRU}corresponds to the set of all variables for resources,
Vdc ={νdc
xxD}corresponds to the set of all variables for data containers,
Vdo ={νdo
xxO}corresponds to the set of all variables for data objects,
Vdv ={νdv
xx# »
wdfo # »
rdfo # »
wdfa # »
rdfa dcp}corresponds to the set of all variables for
data flow edges and parameters, and
V=VtViVpVrVdc Vdo Vdv corresponds to the set of all variables.
Finally, for each set MNENI, each y{t, ip, r, dc, do, dv}, and each xNEwe
define:
VM
y={νy
xνy
xVyxM},
VM=VM
tVM
iVM
pVM
rVM
dc VM
do VM
dv ,
VM
T MP =VM
tVM
iVM
p,
VM
RD =VM
rVM
dc VM
do VM
dv , and
VM
x={νy
xνy
xVM}.
Based on these variables, Table 2-4 introduce a set of transformation patterns
Γ, which map the elements of an eCRG to conditions over predicates. Further,
these tables comprise function φ, which defines the affiliation of each element;
i.e. the superordinated element.
For each pattern class cC(except I) and each node nN, Def. 9 summarizes
the conditions, which are derived by applying the transformation patterns Γto
the corresponding elements. Finally, the resulting terms are used to specify the
transformation in Def. 10.
Definition 9 (Pattern Conditions).
Let Ψ=(N, E, )be an eCRG, let cC{I}be a pattern class, and let nNbe a node. Then
ξc=
xc
Γ(x)corresponds to the conjunction of all conditions of pattern c,
ζc
n=
xc
φ(x)=n
Γ(x)corresponds to the conjunction of all conditions of pattern cfor node n.
On the Formal Semantics of the Extended Compliance Rule Graph 17
Table 2: Transformation Pattern for Nodes
x Γ (x)φ(x)
αT Start(νt
s(α), νi
α, type(α)) End(νt
e(α), νi
α, type(α)) νt
s(α)νt
e(α)α
βMRReceive(νt
β, νi
β, type(β), bp(β)) β
βMSSend(νt
β, νi
β, type(β), bp(β)) β
τPtrue τ
γRtrue γ
ωDtrue ω
δOtrue δ
Table 3: Transformation Pattern for Edges
x Γ (x)φ(x)
e=(α, β, relt)
# »
sf νt
ανt
βrelt(α, β)if αNAA NCA then αelse β
e=(α, β)
# »
mf νi
α=νi
βif αNAA NCA then αelse β
e=(α, β, cont)
# »
tde (νt
e(α)νt
s(β)cont(∣νt
e(α)νt
s(β)∣)) if αNAA NCA then αelse β
(νt
e(β)νt
s(α)cont(∣νt
e(β)νt
s(α)∣))
(νt
s(α)<νt
e(β)νt
s(β)<νt
e(α)cont(0))
e=(α, p, ω)
# »
wdfc W rite(, νi
α, p, νdv
e, νdc
ω)α
e=(ω, α, p)
# »
rdfc Read(, νi
α, p, νdv
e, νdc
ω)α
e=(α, p, δ)
# »
wdfo W rite(, νi
α, p, νdv
e,)νdo
δ=νdv
eα
e=(δ, α, p)
# »
rdfo Read(, νi
α, p, νdv
e,)νdo
δ=νdv
eα
e=(α, γ)
# »
pfm P erform(νi
α, νr
e)InStaff(νr
γ, νr
e)α
e=(γ, η, relr)#»
rr relr(γ, η)γ
e=(δ, , reld)
dr reld(δ, )δ
e=(α, ω, cond)
# »
dcec val(νt
α, ω, νdv
e)cond(νdv
e)α
e=(α, ω, δ)
# »
dceo val(νt
α, ω, νdo
δ)α
Table 4: Transformation Pattern for Attachments
x Γ (x)φ(x)
a=(α, p, cond)dcp P arameter(νi
α, p, vdv
a)cond(vdv
a)α
a=(o, cond)doc cond(νdo
o)φ(o)
a=(e, cond)dfc cond(vdv
e)φ(e)
a=(e, δ)dfo vdv
e=νdo
δφ(e)
a=(α, relt)td relt(νt
s(α), νt
e(α))α
a=(γ, conr)rc conr(νr
γ)γ
18 Knuplesch, Reichert, Ly, Kumar, Rinderle-Ma
Definition 10 (Transformation).
The semantic of an eCRG Ψ=(N, E, )is expressed by the following FOL formula Λ(Ψ):
Λ(Ψ)=Θ(VAO
T MP )
(Θ(VAO
RD )ξAO)
(
nT MP AA Θ(VAA
n)Θ(VAO
RD VAA
RD )ξAO ζAA
n)
Θ(VCO
T MP )
(Θ(VAO
RD VCO
RD )ξAO ξCO )
(
nT MP CA Θ(VCA
n)Θ(VAO
RD VCO
RD VCA
RD )ξAO ξCO ζCA
n)
Thereby, Θ(W)is replaced by the comma-separated concatenation of the vari-
ables contained by a set WV. For example Θ({ν1, ν2, ν3}) would be replaced
by ν1, ν2, ν3’. In case of the empty set (i.e., W=), Θ(W)is replaced by a
dummy variable.
Note that the transformation specified in Def. 3-10 is neither able to deal with
exclusive and alternative connectors nor with multiple consequence patterns.
Hence, we formally introduce exclusive and alternative connectors as well as
multiple consequences in Def. 11.
Definition 11 (eCRG with multiple consequences, exclusive & alternative connectors).
An eCRG with exclusive and alternative connectors is a tuple Ψ+=(N, E, , ex, alt). Thereby
Ψ=(N, E, )is an eCRG and
ex 2TMSMRPis the set of exclusive connectors between task nodes, sending message
nodes, receiving message nodes, and points in time and
alt 2TMSMRPis the set of alternative connectors between task nodes, sending message
nodes, receiving message nodes, and points in time.
T, MS, MR, P Nare the distinct sets of task nodes, sending message nodes, receiving message
nodes, and points in time of Ψ(cf. Def. 4). We define
Nex =
χex
χas the set of nodes contained in the set of exclusive connectors,
Nalt =
χalt
χas the set of nodes contained in the set of alternative connectors, and
Nex,alt =Nex Nalt as the union of these two sets.
As opposed to Def. 7,
SC is the set of pairwise disjoint consequence patterns, and
CiSC with CiNEcorresponds to a particular consequence pattern and COi(CAi)
is the corresponding consequence occurrence pattern (consequence absence pattern).
Exclusive and alternative connectors either connect elements of the antecedence
pattern solely or elements of the same consequence pattern. Consequently, we
can partition the set of exclusive and alternative connectors as well as the related
sets of nodes (Nex,Nalt,Nex,alt) into antecedence and consequence connectors.
We use exponents Aand Cito indicate the corresponding subset.
An exclusive connector is satisfied if the condition related to exactly one of its
nodes (and connected edges and attachments) is satisfied. In turn, the conditions
related to the other nodes of the exclusive connector must be violated. Thus, to
On the Formal Semantics of the Extended Compliance Rule Graph 19
solve an exclusive connector we can split it into different cases, whereby each
case corresponds to the selection of one node. In this context, the selected node
remains unchanged, while all other nodes of the exclusive connector are negated
(i.e. occurrence nodes become absence nodes and vice versa). Finally, the logic
disjunction of all cases expresses the semantics of the exclusive connector. An
alternative connector is satisfied, if the condition related to at least one of its
nodes (and connected edges and attachments) is satisfied. In turn, the conditions
of the remaining nodes are irrelevant. According to exclusive connectors, we can
solve an alternative connector by splitting it into its different cases, whereby each
case corresponds to the selection of one node. In this context, the selected node
remains unchanged, whereas the remaining nodes of the alternative connector
are removed. Again, the logic disjunction of all cases expresses the semantics of
the alternative connector. In Def. 12 formally introduce selections of nodes first,
which correspond to the cases mentioned above.
Definition 12 (Selections).
Let Ψ+=(N, E, , ex, alt)be an eCRG with multiple consequences, exclusive and alternative
connectors. Then
τNAis an antecedence selection choosing one node out of each exclusive and alternative
antecedence connector; i.e., χexAaltAτχ=1,
τ1=NA
ex,alt τis the complement of τ,
υNCiis a consequence selection choosing one node out of each exclusive and alternative
consequence connector of Ci; i.e., χexCialtCiτχ=1,
υ1=NCi
ex,alt υis the complement of υ,
ΠA={τNex,alt (NAO NAA)∣χexAaltAτχ=1}is the set of all antecedence
selections, and
ΠCi={υNex,alt (NCOiNCAi)∣χexCialtCiυχ=1}is the set of all consequence
selections of consequence pattern Ci.
As aforementioned, each selection configures the pattern class of nodes; i.e. se-
lected nodes remain in their class, while the non-selected ones change their pat-
tern class (exclusive connector) or are removed (alternative connector). Def. 13
specifies these node configurations in detail.
Definition 13 (Configuration of Nodes).
Let Ψ+=(N, E, , ex, alt)be an eCRG with multiple consequences, exclusive and alternative
connectors, and let τΠAbe an antecedence selection and υΠCibe a consequence selection.
Then
N(AO)=(NAO Nex,alt)(τNAO
ex,alt)(τ1NAA
ex )corresponds to the configuration of
antecedence occurrence nodes NAO based on τ,
N(AA,τ)=(NAA Nex,alt)(τNAA
ex,alt)(τ1NAO
ex )corresponds to the configuration of
antecedence absence nodes NAA based on τ,
N(COi)=(NCOiNex,alt)(υNCOi
ex,alt)(υ1NCAi
ex )corresponds to the configuration
of antecedence occurrence nodes NCOibased on τ,
N(CAi)=(NCAiNex,alt)(υNCAi
ex,alt)(υ1NCOi
ex )corresponds to the configuration
of antecedence absence nodes NCAibased on τ,
20 Knuplesch, Reichert, Ly, Kumar, Rinderle-Ma
Node configurations affect the corresponding edges and attachments as well.
Thus, Def. 14 (re-)configures the definition pattern classes from Def. 7:
Definition 14 (Configuration of Classes).
Let Ψ+=(N, E, , ex, alt)be an eCRG with exclusive and alternative connectors, and let τΠA
be an antecedence selection and υΠCibe a consequence selection. Then:
E(AO)={eEAnd(e)N(AO)}is the configuration of antecedence occurrence edges
based on τ,
E(AA,τ)={eEAnd(e)N(AA,τ) nd(e)N(AO)}is the configuration of
antecedence absence edges based on τ,
E(COi)={eECind(e)(N(COi)N(AO))} is the configuration of consequence
occurrence edges based on τand υ,
E(CAi)={eECind(e)N(CAi) nd(e)(N(COi)N(AO,τ ))}is the
configuration of consequence absence edges based on τand υ,
(AO)={aAat(a)N(AO)E(AO)}is the configuration of antecedence occur-
rence attachments based on τ,
(AA,τ)={aAat(a)N(AA,τ)E(AA,τ )}is the configuration of antecedence absence
attachments based on τ,
(COi)={aCiat(a)N(AO)E(AO)N(COi)E(COi)}is the configura-
tion of consequence occurrence attachments based on τand υ,
(CAi)={aCiat(a)N(CAi)E(CAi)}is the configuration of consequence
absence attachments based on τand υ,
AOτ=N(AO,τ )E(AO)(AO)is the configuration of the antecedence occurrence
pattern based on τ,
AAτ=N(AA,τ)E(AA,τ)(AA,τ )is the configuration of the antecedence absence pattern
based on τ,
CO(τ)
i=N(COi)E(COi)(COi)is the configuration of the consequence oc-
currence pattern based on τand υ,
CA(τ)
i=N(CAi)E(CAi)(CAi)is the configuration of the consequence
absence pattern based on τand υ,
Aτ=AOτAAτis the configuration of the antecedence pattern based on τ, and
C(τ)
i=CO(τ)
iCA(τ)
iis the configuration of the consequence pattern based on τand υ,
HAτ=AAτare the elements of the antecedence pattern that are masked during its
configuration based on τ,
HC(τ)
i=CiC(τ)
iare the elements of consequence pattern Cithat are masked during
its configuration based on τand υ.
Based on Def. 14, we are able to enrich the transformation from Def. 10 with the
support for exclusive and alternative connectors as well as multiple consequences
in Def. 15.
On the Formal Semantics of the Extended Compliance Rule Graph 21
Definition 15 (Transformation).
The semantics of an eCRG Ψ+=(N, E, , ex, alt)with multiple consequences, exclusive and
alternative connectors is expressed by the following FOL formula Λ+(Ψ+):
Λ+(Ψ+)=
τΠAΘ(VAOτ
T MP )
((Θ(VAOτ
RD )ξAOτ)
(
nT MP AAτΘ(VAAτ
n)Θ(VAOτ
RD VAAτ
RD )ξAOτζAAτ
n) )
CiSC
υΠCi
Θ(VCOτ
i
T MP )((Θ(VAOτ
RD VCOτ
i
RD )ξAOτξCOτ
i)
(
nT MP CAτ
i
Θ(VCAτ
i
n)Θ(VAOτ
RD VCOτ
i
RD VCAτ
i
RD )ξAOτξCOτ
iζCAτ
i
n))
For example, Def. 10 and Def. 15 translate eCRG c4from Fig. 10A into:
Λ(c4)=νt
PS, νt
PE, νi
P, νp
P
(νdo
O, νdv
(O,P )
Start(νt
PS, νi
P,Prod.)End(νt
PE, νi
P,Prod.)νt
PSνt
PE
Read(, νi
P,, νdv
(O,P ),)νdo
O=νdv
(O,P ))
(νt
CS, νt
CE, νi
C, νp
Cνdo
O, νdv
(O,P ), νdv
(O,C)
Start(νt
PS, νi
P,Prod.)End(νt
PE, νi
P,Prod.)νt
PSνt
PE
Read(, νi
P,, νdv
(O,P ),)νdo
O=νdv
(O,P )
Start(νt
CS, νi
C,Chg.)End(νt
CE, νi
C,Chg.)νt
CSνt
CE
νt
PSνt
CS
Read(, νi
C,, νdv
(O,C),)νdo
O=νdv
(O,C))
5 Pattern-based Evaluation
This section outlines a pattern-based evaluation of the eCRG language. In partic-
ular, we model the compliance patterns introduced in [9, 11, 29] with the eCRG
language. These patterns result from literature and case studies, and thus consti-
tute a suitable empirical basis for evaluating the appropriateness of our approach.
5.1 Business Process Control Pattern and Property Specification
Pattern
27 business process control patterns (BPCPs) for modeling compliance rules are
introduced in [11]. They include all property specification patterns from [54]. Out
of the 27 BPCPs, 15 BPCPs focus on the control flow (i.e., process) perspective,
7 BPCPs focus on the resource perspective, and 5 BPCPs focus on the time
perspective. In turn, the data perspective is implicitly supported by each BPCP,
since BPCPs do not distinguish between tasks and data conditions. Fig. 11
shows how to model the 15 control flow BPCPs with the eCRG language. In
turn, Fig. 12 provides eCRGs that model the 7 resource BPCPs and the 5 time
BPCPs.
22 Knuplesch, Reichert, Ly, Kumar, Rinderle-Ma
Q P
Q P
QP
Q P
Q P = 0
Precedes
LeadsTo
XLeadsTo
PLeadsTo
Q S P T
S PQ T
ChainLeadsTo
ChainPrecedes
P
Q
S
T
LeadsTo-Else
P
Exists
Absent
P
P
P
¬P
Universal
Q P
Q P
CoExists
CoAbsent
Exclusive
CoRequisite
Q P
P Q
Q P
Q P
v
QPMutexChoice
Fig. 11: control flow BPCPs
Q
P
PerformedBy
SegregatedFrom
is
P Q
is is
P Q
USegregatedFrom
P Q
is
BondedWith
P Q
is is
RBondedWith
P Q
S
P Q
is
S
Multi-Segregated
Multi-Bonded
Q P < k
Within k
After k Q P > k
Q P = k
Q
= k
ExactlyAt k
P
> k
Exists Max/Min k P
< k
Exists Every k Q
< k
every k
start
Fig. 12: Resource and time BPCPs
On the Formal Semantics of the Extended Compliance Rule Graph 23
Note that most BPCPs can easily be modeled using the eCRG language. How-
ever, from our subjective point of view the modeling of the XLeadsTo BPCP, the
Universal BPCP, the Exists Max/Min BPCP, and the Exists Every k BPCP was
a bit more complicated. In turn, Fig. 12 provides an eCRG for the special case of
the Multi-Segregated BPCP, which requires the numbers of performers and tasks
to be equal. Other cases of the Multi-Segregated BPCP can not be modeled us-
ing only one consequence pattern; e.g., in case that the Multi-Segregated BPCP
requires 4 tasks to be executed by 3 different performers (i.e., one performer
must execute two tasks), (4
2)=6 consequence patterns are required. Hence the
Multi-Segregated BPCP is the only BPCP that cannot always be appropriately
modeled using the eCRG language.
5.2 Compliance Rule Pattern
55 control flow compliance rule patterns (CRPs) are introduced in [9]. Further,
one example of the data perspective and another one of the resource perspective
are presented. The 55 control flow CRPs are partitioned into 15 categories. Note
that 7 categories and the respective CRPs fully coincide with the aforementioned
BPCPs (cf. Table 5). The remaining 8 categories and respective CRPs are mod-
eled with the eCRG language in Figs. 13-16. Fig. 17 contains both examples
illustrating the data and resource perspectives.
Table 5: Intersection between BPCPs and CRPs
Compliance rule pattern Business process control pattern
Existence - Event universality Exists
Existence - Event absence Absent
Exclusive Exclusive
Mutual Exclusive MutexChoice
Prequisite CoAbsent
Inclusive CoExists
Substitute LeadsTo-Else
CoRequisite CoRequisite
24 Knuplesch, Reichert, Ly, Kumar, Rinderle-Ma
A
Bounded Existence
Exactly k times A
Bounded Existence
At least k times
A
A A
Bounded Existence
At most k times A A A
Bounded Existence
Exactly k times in a row
Bounded Existence
At least k times in a row
Bounded Existence
At most k times in a row
A A
A A
A
v
A A
A A
A
A
B
A
Between
After - Before C
Between
Simultaneously or after
Before
B
B
A
C
Between
After
Simultaneously or before
C
A
Between
Directly after
Directly before
A C B
B
A
A
C
Between
Simultaneously
Simultaneously
Between
Simultaneously or after
Simultaneously or before
B
A
C
Between
At least one
other activity
A B
B A
v
Fig. 13: Bounded existence CRPs and between CRPs
A1 A2
A3
Chain Precedence
Direct
B1 B2
B3
Chain Precedence
Direct or indirect
A1 A2
A3
B1 B2
B3
A1 A2
A3
B1 B2
B3
Chain Precedence
Never direct
Chain Precedence
Never
A1 A2
A3
B1 B2
B3
A1 A2
A3
Chain Response
Direct
B1 B2
B3
Chain Response
Direct or indirect
A1 A2
A3
B1 B2
B3
A1 A2
A3
B1 B2
B3
Chain Response
Never direct
Chain Response
Never
A1 A2
A3
B1 B2
B3
Fig. 14: Chain precedence CRPs and chain response CRPs
On the Formal Semantics of the Extended Compliance Rule Graph 25
Bounded Sequence
One to one coexistence
Bounded Sequence
Coexistence
A
A B
B
A
B A
B
A
B A
B
A
A B
B
v
A B
B A
v
A B
B A
v
A B
B A
B A
Bounded Sequence
Exactly k times
A B
A B
B A
B A
B A
Bounded Sequence
At least k times
Bounded Sequence
At most k times
Parallel A
v
B
A
B
B
A
B
A
Fig. 15: Bounded sequence CRPs and parallel CRPs
26 Knuplesch, Reichert, Ly, Kumar, Rinderle-Ma
Precedence
Simultaneus or before
Precedence
Direct
Precedence
Direct or indirect
B
A
A B
A B
B
Precedence
At least once A B
B
B
A
Precedence
Direct multiple events
Precedence
Direct or indirect
multiple events
A B
Precedence
Direct multiple
different events
C
B
A
C
B
A
Precedence
Direct or indirect multiple
different events
Precedence
Never direct B A
BA
Precedence
Never
Response
Simultaneus or after
Response
Direct
Response
Direct or indirect
A
B
A B
A B
A
Response
At least once A B
B
A
A
Response
Direct multiple events
Response
Direct or indirect
multiple events
A B
Response
Direct multiple
different events
Response
Direct or indirect multiple
different events
Response
Never direct B A
BA
Response
Never
B
A
C
B
A
C
Fig. 16: Precedence CRPs and response CRPs
B A
grant
customer
record
is silver
discout
= 5%
grant
customer
record
is gold
discout
= 10%
Data-flow Organizaitional
v
Fig. 17: Data flow CRPs and resource CRPs
On the Formal Semantics of the Extended Compliance Rule Graph 27
Note that most CRPs can easily be modeled using the eCRG language. However,
from our subjective point of view a thinking outside the box was required when
we modeled the Bounded Existence - Exactly k times in a row CRP, the Bounded
Existence - At most k times in a row CRP, the Between - Simultaneously, Si-
multaneously CRP, and all Bounded Sequence CRPs - especially in case of the
Bounded Sequence - One to one coexistence CRP.
5.3 Time Pattern
In [28, 29], a set of 10 time patterns (TPs) is introduced and formally specified.
In Fig. 18, the eCRG language is applied to model these TPs.
A
TP1
Time Lag between
two Activities
B
= 1d
TP2
Duration
A
< 3h
Sender
M
TP1
Time Lag between
Events
TP4
Fixed Data Elements
TP5
Schedule Restricted
Elements
TP6
Time-based
Restriction
TP7
Validity Period
TP 8
Time-dependent
Variability
TP9
Cyclic elements
TP10 Periodicity
12am
< 3h
A B
= 1d
Next
iteration
9 April 2014
4:00 pm
< 2h A
start
schedule A
end
schedule
start
frame
end
frame
A A
A
start
validity
end
validity
A
Sender
M
A
Sender
MB
9 April 2014
6:00 pm
9 April 2014
6:00 pm
start
period
end
period
A
Fig. 18: Time Patterns
Note that most TPs can be easily modeled using the eCRG language. However,
from our subjective point of view the modeling of TP6 Time-based Restrictions
and the modeling of TP8 Time-dependent Variability were a bit more compli-
cated.
Fig. 19 summarizes the results of the pattern-based evaluation. Overall, we were
able to model 26 out of the 27 business process control patterns (BPCPs) [11], in-
cluding 5 time BPCPs and 7 resource BPCPs as well. Only the multi-segregation
pattern cannot be properly modeled using the eCRG language in any case. Fur-
ther, the eCRG language supports the 15 categories of compliance rule patterns
28 Knuplesch, Reichert, Ly, Kumar, Rinderle-Ma
and respective rules as well as the data flow and the resource example from [9].
Finally, the eCRG language covers well-known time-patterns [29] as well.
Business process control patterns
Property specification patterns
Compliance rule
pattern categories
Time patterns
Precedes
++
USegregatedFrom
++
Existence
++
Time lags between activities
++
LeadsTo
++
BondedWith
++
Bounded existence
+
Durations
++
XLeadsTo
+
RBondedWith
++
Bounded sequence
+
Time lags between events
++
PLeadsTo
++
Multi-Segregated
-
Parallel
++
Fixed date elements
++
ChainLeadsTo
++
Multi-Bonded
++
Precedence
++
Schedule restricted elements
++
Chain Precedes
++
Within k
++
Chain precedence
++
Time-based restrictions
+
LeadsTo - Else
++
After k
++
Response
++
Validity period
++
Exists
++
ExactlyAt k
++
Chain response
++
Time-dependend variability
+
Absent
++
Exists Max/Min
+
Between
+
Cyclic elements
++
Universal
+
Exists Every k
+
Exclusive
++
Periodicity
++
CoExists
++
Mutual exclusive
++
CoAbsent
++
Inclusive
++
Exclusive
++
Prequisite
++
CoRequisite
++
Substitute
++
MutexChoice
++
Corequisite
++
PerformedBy
++
Data flow
++
SegregatedFrom
++
Organizational
++
++ full support, + inconvenient support, 0 partial support, - minor support, -- no support
Fig. 19: Support of compliance patterns
6 Summary and Outlook
While compliance rule modeling has been introduced by a plethora of approaches,
the data, time, resource and interaction perspectives of compliance rules have
not been sufficiently addressed yet [12, 8–11]. This report has introduced the
extended Compliance Rule Graph (eCRG) language, which is based on the com-
pliance rule graph (CRG) language [15, 24]. As opposed to existing visual com-
pliance rule notations, the eCRG supports multiple perspectives; i.e., beyond
the control flow perspective, data, time, resources, and interactions with busi-
ness partners are considered. To provide tool support for both the modeling and
verification of compliance rules, we have formalized the syntax and semantics of
the eCRG. Finally, we have conducted a pattern-based evaluation to prove the
proper expressiveness of the eCRG language.
In future work, we will conduct experiments to evaluate the usability and scala-
bility of the eCRG. Furthermore, we will develop techniques for verifying com-
pliance of business processes and process choreographies with such rules.
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