=Paper=
{{Paper
|id=Vol-161/paper-34
|storemode=property
|title=Reconciliation of two Business Modelling Frameworks
|pdfUrl=https://ceur-ws.org/Vol-161/FORUM_33.pdf
|volume=Vol-161
|dblpUrl=https://dblp.org/rec/conf/caise/WohedA05
}}
==Reconciliation of two Business Modelling Frameworks==
https://ceur-ws.org/Vol-161/FORUM_33.pdf
201
Reconciliation of two Business Modelling
Frameworks
Petia Wohed1 and Birger Andersson2
1
CRAN, Université Henri Poincaré, Nancy 1/CNRS
BP239, 54506 Vandoeuvre les Nancy, France
petia.wohed@cran.uhp-nancy.fr
2
DSV, Stockholm University/Royal Institute of Technology
Forum 100, SE-164 40 Kista, Sweden
ba@dsv.su.se
Abstract. Addressed in this paper is the problem of conceptual hetero-
geneity within the field of information systems. Two frameworks, Frisco
and Söderström, each reflecting this heterogeneity, are presented. They
are analysed and an reconciliation attempt of them is provided. The rec-
onciliation points at some strengths and weaknesses in each framework.
1 Introduction
Frameworks like Frisco [1] and BWW [2] were developed during the last decade
to adress the terminological fuzziness characterizing the field of information sys-
tems. By proposing a coherent system of concepts their common goal was to
provide a uniform terminology which could be used to reduce misunderstand-
ings and ambiguities. In the same time period, also addressing terminological
heterogeneity, frameworks like those of Söderström [3] and UEML [4] were pro-
posed. They were primarily developed for facilitating structured and unbiased
analysis when comparing business process modelling languages.
While Frisco and BWW are developed top-down, are formal and founded
on solid philosophical foundations, the frameworks of Söderström and UEML
are developed bottom-up, are informal and are grounded on practical rather
than theoretical work. A common feature of these rather orthogonal approaches,
however, is that the achievement of their goals would facilitate the development
of interoperable information systems.
Currently, none of these frameworks has yet received the critical mass of
attention and deployment for attaining their goals. Criticizing Frisco and BWW
for being too theoretical, and Söderström and UEML for not being formalized
and therefore fuzzy, are fair concerns and this criticism has been the motivation
for the work reported in this paper.
In order to take advantage of the strengths and mitigate the weaknesses, a
reconciliation of two of these frameworks, Frisco and Söderström’s, is proposed.
By combining the theoreticians’ with practitioners’ work, we hope to achieve
a good mixture of sound theoretical grounding with user-friendliness, thereby
increasing the understandability and applicability of the result. This paper pro-
ceeds by first presenting both frameworks followed by an analysis and an attempt
to reconcile them.
Proceedings of the CAiSE'05 Forum - O. Belo, J. Eder, J. Falcão e Cunha, O. Pastor (Eds.)
© Faculdade de Engenharia da Universidade do Porto, Portugal 2005 - ISBN 972-752-078-2
202 Petia Wohed, Birger Andersson
2 Söderström’s Framework
This section is opened by presentation of the framework taken from [3], followed
by discussion of its ambiguities. The meta-model is reprinted in figure 1.
“Most process modelling languages include at least four basic concepts:
time point, activity, state and event, [..]. Intuitively, a time point is an
instant in time, not further decomposable. An activity is a performance
of some sort, possibly changing some thing’s state, i.e. its set of prop-
erties. An event is a noteworthy occurrence. Usually, one is interested
in particular events associated with changes of state, i.e. activities are
involved in some way.
– Events can either record a certain point in time (time point event)
or record the time between two time points (time duration events).
– Events can either record the start of an activity (pre-activity events)
or record the end of an activity (post-activity events).
– Events may record the change of a state (state change events) or
not.
A process is modelled [..] as a structure of logical dependencies between
activities. These activities use one or more resources as input, and pro-
duces one or more resources as output. One specific type of resource, the
role, is regarded to be responsible for that one or more activities will be
performed.
The execution of a process is regarded to be a time-bound series of
events, caused by an actor. These events may result in a state change
for a resource. An actor who causes an event always has an intention
with his/her actions to achieve a specific state for a resource. The state
can be either different from the resource’s current state, or it can be the
same state as the current one.
[..] An event always occurs at certain time point or between two time
points on a certain location.”
Furthermore, the model is divided into two levels: a type level, containing ac-
tivity, resource, role, activity dependency and process; and an instance level
containing event, state, actor and temporal dependence.
The pronouns: where, who, how, what, and why have been added into the
framework to enhance its readability. However, as they do not bring any addi-
tional semantic we have left them out of our discussion.
From the description provided above the following questions arise.
– How are the entities Process and Activity Dependency related to each other?
A process is composed of a number of activities, strictly defining the order
between them, while Activity Dependency is the entity aimed for capturing
in pairs the ordering between activities.
– What in the framework is referred to as type and instance level is what we
associate to Fowler’s knowledge and operational level [5]: operational level
aimed for capturing the day to day events of a domain; and knowledge level
203
Sequence Fork
1..1 Selection
Responsible isa
Role isa
isa
Merge
Activity isa
4M 1..1
Relating_act
Dependency
isa 1..* 1..* 1..1
isa
Inputs Related_act Motivate
1..* Activity 1..*
1..*
Resource 1..* 1..*
1..* Outputs
Rule
isa Modelled_as
A_type
Information 1..*
Govern
E_type Process
S_type 1..1
Executed_as Temporary
1..1
Before Dependency
State 1..1
Changes 1..* 1..1
0..1 After
isa 1..1 1..1 Takes_place_at
Goal Event 0..*
Location
1..1
1..* isa Duration 0..1
1..*
1..1 Event 0..1 Starts_at
Has_intention Cause isa isa 1..1
Ends_at
isa 1..1 Time
Actor 1..* Time-point
Pre-Activity Point
Post-Activity Event 0..1 1..1
Event
Event Occurs_at
Who Why What How When Where
Fig. 1. Söderström’s meta-model
capturing general rules governing in the domain and the events occurring
within it. A consequence of Fowler’s approach, is that many of the enti-
ties at the operational level tends to more generally be described through
(i.e., mapped to) corresponding entities at the knowledge level. For instance,
an Actor performing an Event (both modelled at the operational level) are
through the relationships A type and E type mapped to Role responsible for
an Activity at the knowledge level. For instance, the Event 1 April 2004 Eva
books flight tickets performed by Eva (an Actor) in her Role of secretary
implying the responsibility of tickets booking Activity. Likewise, the Process
Travel planning and accomplishment (at knowledge level) could at opera-
tional level be exemplified by Ann’s travel planning and trip to London.
However, there is not any corresponding entity to Process at operational
level. The question arising is: Why are some entities at operational level
missing corresponding entities at knowledge level?
– According to the mapping constraints one role is responsible for the perfor-
mance of an activity. However, some activities are allowed to be performed by
the holders of different roles. This would in the model be captured through
the Input relationship between Resource (as a generalization of Role) and
Activity, which is not an intuitive solution. Furthermore, the isa relation-
ship between Role and Resource is not entirely clear. Applying the opera-
tional/knowledge level thinking introduced by Fowler, this isa relationship
would transfer to an isa relationship between Actor and State entities in the
operational level. As this generalization/specialization does not make any
sense it is naturally not present in the framework. However, this ambiguity
confirms the need for further clarification of the concepts in the framework.
204 Petia Wohed, Birger Andersson
– The notion of non state changing events is somewhat ambiguous, as one
could claim that events are capturing state changing phenomena.
– Rule, 4M, and Information concepts are currently not described in the natural
language description of the framework.
3 Frisco
In this section a brief introduction to the relevant parts of Frisco [1] is given. A
UML meta-model is drawn in figure 2.
The world is made up of Things. A thing is either an Elementary or a Composite
thing. Composite things are build up through Relationships. Relationships are sets
of binary tuples, the elements of which are things: the first element in a tuple
is called a Predicated thing and the second element a Predicator. Relationships
are themselves considered as things, which makes it possible to represent the
complex structures often existing in a domain.
Furthermore, a special kind of relationship, consisting of a couple of tuples,
called Transition, is introduced. The predicators in the tuples within a transi-
tion are the primitives before and after and the predicated things are composite
things, so called States. Complex transitions can be build up through Sequence,
Choice and Concurrency State Transitions Structures. A coherent state transition
structure, i.e., a structure with a unique input (before) state and a unique out-
put (after) state, is called a Composite Transition. Furthermore, Rules are used
to define the set of permissible states and transitions in a context.
Concurrency
StateTransition
Rule Choice
Structure
consists of 0..* defines 0..* involves v
Sequence
permissable v permissable v involves v
* * 11
1 < pre *
State 1 < post
Transition Composite
*
1 1 1
Transition
< of *
< states of > Time
* Goal < pre *
Transition
desired 1 Unit
* < post * occurrence
Output
*
Actand Composite Time
Input Actand * Action
* Action Interval
Actand < involves * 1 * *
start v end v
1 1
< involves < of *
Action Time
Resource Actor 1 occurrence Point
Fig. 2. Frisco - a partial metamodel
Transitions which are performed by someone are distinguished and called
Actions. Actions are presented through a couple of tuples, the predicated thing
of the first of which shows the performing Actor and of the second one the
transition he/she is performing. The predicators used for describing this are the
205
primitives performing and performed-by, correspondingly. The things involved in
the input and the output states of an action, and which are not actors for that
action, are called Actands. The input actands for an action (i.e. the actands from
the input state) together with the actors are the Resources for that action. Also
using the primitive is-context, some of the input actands can be predicated, in
order to define the Action context. In a similar way the Goal of an action can be
defined by intentionally stating the desired output state.
During the analysis of Frisco, few ambiguities were discovered and some im-
provements suggested. These resulted in the definition of Time Point, Time In-
terval, Time Unit, Entity Type and Action Occurrence concepts (see the shaded
classes in figure 2) Due to space limitation, for details and formal definitions the
reader is referred to [6].
4 Mapping the Frameworks
The mapping of the frameworks we suggest is provided in table 1. Hence, the
formal definitions in Frisco [1] and [6], provides a formalization of Söderström’s
framework.
Söderström Frisco Söderström Frisco
Activity Action Event Action Occurrence
Process Composite Action Duration Event Action Occurrence
(Process Occurrence) (of comp. action)
Resource Resource Time-point Event Action Occurrence
Output Actand (of non comp. action)
Resource Input Actand Pre-activity Event –
Resource Output Actand Post-activity Event –
Role Entity Type Actor Actor
4M – State State
Information – Goal Goal
Activity State Transition Temporal –
Dependency Structure Dependency
Sequence Sequence Location –
Fork Concurrency Time point Time point
Select Choice – Time interval
Merge (Choice+Sequence) – Time unit
Rule Rule – Action context
Table 1. Mapping of the frameworks
As indicated by the empty cells, there are concepts which can not be mapped
directly. For instance the Location concept, as well as Pre- and Post-activity
Event concepts are lacking in Frisco. We have also for the moment refrained map-
ping the concepts Information, 4M and Temporal dependencies from Söderström
as we are lacking sufficient understanding of them. However, by providing a for-
mal foundation for Söderström’s framework, further elaboration and clarification
of these concepts is facilitated.
206 Petia Wohed, Birger Andersson
The central concepts of Söderström’s framework, i.e., the concepts Activity
and Event are mapped into Frisco’s Action and Action Occurrence, correspond-
ingly. Process is mapped to Composite Action, which also implies certain changes
to it. Namely, the fact that a Composite Action is defined as subtype to Action,
forces the same semantic on the relationship between Process and Activity.
Furthermore, an Action Occurrence of a Composite Action, which is pos-
sible to express in Frisco, would actually correspond to a Process Occurrence.
However, no such concept exists in Söderström. Instead, the distinction between
Duration and Time-point Events indicating the time-span differences is made.
This is also one of the differences captured by Action Occurrence of composite
actions versus Action Occurrence of actions which are not composite. Therefore
these concepts are mapped on each other as proposed in the table. Note, though,
that this mapping forces the semantics of a composite action consisting of a num-
ber of actions, into Duration Event, which was not actually explicitly stated in
Söderström. This implies also that the term Duration Event is unnatural and
the term Process Occurrence, given in brackets, is suggested.
Moreover, Frisco has a more fine-grained conceptualization of resources spec-
ifying a Resource to be an Actor or an Input Actand (i.e., the object on which an
action is performed) and distinguishing them from the Output Actands (i.e. the
results from actions). As this distinction is not made in Söderström, the Resource
concept of it is mapped into the union of Resource and Output Actand.
Finally, as a Role is specified to be responsible for the performance of an
Activity, which corresponds to the Entity Type specified for the performance of
an Action, Role and Entity Type are mapped to each other. Activity Dependency
with its subclasses has been mapped into State Transition Structure with the
corresponding subclasses. Also Söderström’s Actor, State, Goal, Rule, and Time
Point have directly been mapped into the corresponding Frisco concepts.
To visualize the result we propose a UML meta-model in figure 3. The classes
are denoted by the terms from Söderström in the upper half of the rectangles
and the terms from Frisco in the bottom half. Only the concepts supported by
Frisco’s formal definitions are presented.
From this meta-model it can be seen that the ambiguity of the relationship
between Process and Activity Dependency have now been solved. Furthermore,
the isa relationship from Role to Resource has been removed, hence the ambi-
guity around it solved. The Resource entity has been split into two entities, i.e.,
Input- and Output Actand entities. The Rule entity has got a clear semantic.
The State entity has explicitly been related to several other concepts.
5 Conclusions
Concluding the discussion we would like to stress the following points. The dis-
tinction of Knowledge/Operational levels provided in Söderström forced some
clarifying changes in this matter in Frisco [6]. As the level distinction is still not
complete for all of Frisco’s concepts and we believe that further work in this
direction would bring additional benefits to the framework.
207
Goal Sequence Fork Selection
Goal Sequence Concurr Choice
1
Actor * ActionOccur * Time Unit
1 1
Time-pontEvent Time Point
nonCompActionOccur Time Point
Fig. 3. Consolidated Model
Furthermore, formalizing Söderström’s framework have resulted in clarifi-
cation of it. However, not being able at this stage to capture all its concepts
especially the various Event Types is a concern. The formalization proposed
here is, however, a first step providing the necessary ground on which further
conceptualization refinement can be made.
Finally, one of the major benefits of this integration is that its result, as
a combination of a graphical with a formal representation, facilitates further
cross-analysis of the approach with similar attempts in the area [2, 7].
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