=Paper= {{Paper |id=Vol-3618/forum_paper_9 |storemode=property |title=Data-centric goal modeling for knowledge-intensive processes |pdfUrl=https://ceur-ws.org/Vol-3618/forum_paper_9.pdf |volume=Vol-3618 |authors=Anjo Seidel,Charlotte Balcke,Mathias Weske |dblpUrl=https://dblp.org/rec/conf/er/SeidelBW23 }} ==Data-centric goal modeling for knowledge-intensive processes== https://ceur-ws.org/Vol-3618/forum_paper_9.pdf
                                Data-centric goal modeling for knowledge-intensive
                                processes
                                Anjo Seidel1,∗ , Charlotte Balcke1 and Mathias Weske1
                                1
                                    Hasso Plattner Institute, University of Potsdam, Prof.-Dr.-Helmert Str. 2–3, Potsdam, 14482, Germany


                                                                         Abstract
                                                                         Knowledge-intensive processes are both data-centric and goal-oriented. Data is manipulated by processes,
                                                                         and knowledge workers can terminate a process once its goal has been reached. Despite the fact that
                                                                         formally defined goals are crucial for effective process executions, no visual notation for modeling
                                                                         goals in knowledge-intensive processes has been introduced yet. This paper proposes to model goals
                                                                         graphically as UML object diagrams that are consistent with the UML class diagrams describing the
                                                                         data, which is manipulated by knowledge-intensive processes. A prototypical implementation provides
                                                                         a visual modeler for goals in knowledge-intensive processes.

                                                                         Keywords
                                                                         Business Process Management, Knowledge-intensive Processes, Data-centric Processes, Goal Modeling,
                                                                         Fragment-based Case Management




                                1. Introduction
                                In business process management (BPM), process models are used to depict and support real-
                                world processes [1]. A special class of business processes is knowledge-intensive processes
                                (KiPs), which are especially unpredictable, emergent, and complex [2]. Knowledge workers drive
                                those processes and aim to attain specific goals, which are desirable states of a business process.
                                In order to reach such a goal, knowledge workers plan their actions, rendering decision-making
                                an essential part of their work [3]. Actions for the current situation are chosen in regard to
                                process instance-specific goals [4]. Often it is not trivial to identify actions that align with one’s
                                goals and knowledge workers can benefit from recommendations for the next best actions [5].
                                Furthermore, automatic planning can support knowledge workers but requires defined process
                                instance goals as well [4].
                                   Different data-centric modeling approaches, like BAUML [6], OCBC [7], and fragment-based
                                case management (fCM) aim to model KiPs. They model involved data objects using UML
                                class diagrams as domain models and combine them with behavioral models. Goals need to be
                                concerned with the data that is manipulated during process executions.
                                   Goals for knowledge-intensive processes can be defined as a combination of objectives.
                                Objectives are sub-goals that make quantifiable statements about a case [8]. They can be
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                                ∗
                                    Corresponding author.
                                Envelope-Open anjo.seidel@hpi.de (A. Seidel); charlotte.balcke@student.hpi.de (C. Balcke); mathias.weske@hpi.de (M. Weske)
                                Orcid 0000-0002-9652-5340 (A. Seidel); 0000-0002-3346-2442 (M. Weske)
                                                                       © 2023 Copyright for this paper by its authors. Use permitted under Creative Commons License Attribution 4.0 International (CC BY 4.0).
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combined into long-term goals. Goals that are within the scope of an fCM model can be
formally defined as partial orders of objectives [5]. Objectives are first-order logic statements
over single execution states of the process model. Until now, no graphical notation for such
goal models was provided, which could ease the accessibility for modelers compared to formal
expressions.
    In this paper, we propose a graphical visualization of data-centric goals for knowledge-
intensive processes and the means for formal verification of goals and process models. This
enables knowledge workers to model their desired process outcomes flexibly and receive
recommendations accordingly. Based on fCM, we show how (i) data-centric objectives can
be modeled with UML object diagrams, which are instances of the process model’s domain
model. (ii) Goals can be represented as dependency graphs that order objectives. We provide
an interpretation of these graphical goals that conforms to the one by Seidel et al. [5], so
they can be used for the same formal verification and computation of planning support. A
prototypical implementation allows for visually modeling data-centric goals that are compliant
with fragment-based case models. The prototype allows for deriving recommendations by
filtering suitable from non-suitable actions with regard to a modeled goal.
    In the remainder of this paper, we present the related work section 2, before introducing
the preliminaries to our approach in section 3. In section 4, the notation and semantics of
data-centric goals are elaborated. A prototypical implementation is presented in section 5,
before section 6 concludes the paper.


2. Related work
Our contribution is based on different previous streams of work regarding KiPs and KiP models,
and goal modeling for BPM.
   Di Ciccio et al. provide a definition and a set of characteristics for KiPs and requirements
towards modeling them [2]. KiP models need to support data and goal modeling during run-time.
Meanwhile, Pyoria et al. define decision-making during process execution as a crucial task of
knowledge workers [3].
   Declarative and data-centric process modeling approaches have been developed to model
KiPs. Di Ciccio et al. [2] and Steinau et al. [9] provide an overview of contemporary approaches.
The data-centric approaches BAUML [6], OCBC [7], and fragment-based Case Management
(fCM) [10, 11] combine behavioral models with UML class diagrams to model the involved data
objects.
   Goal modeling is a prominent topic in the context of requirements engineering. Kavakli et
al. [12] and Amyot et al. [13] provide an overview of existing methods. Goal modeling was
combined with BPM in many prior works. Kueng and Kawalek [14] provide an overview of
goal-based business process modeling. Greenwood and Rimassa [15] provide a framework for
automatic goal-oriented BPM. Amyot et al. [16] analyze and summarize existing combinations
of business process modeling with goal modeling in the URN standard. They summarize the
main application fields of aligning process models with goals, process compliance, adaptation
and improvement, and goal-oriented process mining. Other works allow developing process
models from i* goal models [17] and from KAOS goal models [18]. Yet, these goal modeling
approaches for BPM focus on requirements for the process model instead of single process
instances. All those goal models mainly focus on high-level requirements toward the process
model itself during the design-time of process models instead of process instance goals.
   Fewer works focus on the usage of process goals during run-time. Dalpiaz et al. [19] extend
goal models for monitoring their satisfaction during run-time. Ghanavati et al. [20] summarize
the works of using goal models for business process compliance. Marella et al. [21] provide a
framework to map business process models to planning problems including goals as desired
process outcomes. Based on fCM, Haarmann et al. [22] and Seidel et al. [5] provided the means
to formally define the objectives and goals for the outcome of process models during run-time
as first-order logic statements over possible future execution states. For now, those goals are
only defined formally and not visually.


3. Preliminaries
This paper presents an approach to model goals by using UML object diagrams for data-
centric process models. We apply our concepts to the fragment-based Case Management (fCM)
approach. An introduction to fCM is included by providing a running example. Furthermore,
we summarize preliminary works toward the definition and utilization of goals for fCM. Finally,
a short introduction to the relevant UML concepts is given.

3.1. Fragment-based Case Management
The key concept of fCM is the combination of imperative control flow with declarative data
flow. The process is split into fragments that can be combined repeatedly and concurrently
during run-time. Their combination is constrained by the control flow and by data constraints.
An fCM model consists of (i) behavioral process fragments, (ii) a domain model, and (iii) object
lifecycles.

Fragments. The process fragments have a similar syntax to BPMN [10]. They define a set of
activities. For each activity, the required data objects for execution can be defined. Activities
describe possible data changes.
   Consider the example of renovating a house. The process can be modeled with the fragments
displayed in Figure 1. Once the construction site is opened, the work on the house is started in
fragment F1. Then, the house is considered to be started and the work on the staircase and on
the apartments can start as well. According to one’s needs, the house can be split into multiple
apartments. In fragment F2, new apartments can be created. For each apartment, multiple
tasks need to be done. As specified in fragment F3, for an initial or painted apartment, tiles are
laid. In fragment F4, an apartment, initial or with tiles, is painted. It can be painted with either
yellow or green paint. An apartment can be painted and tiled concurrently. Afterward, the
kitchen can be installed in fragment F5 and the apartment is considered finished. The finished
apartments are a preliminary in fragment F1 to paint the staircase. Afterward, the house can be
checked and accepted.
Figure 1: Fragments for the house renovation process.


Domain model. The domain model of the fCM model is modeled with a UML class diagram.
It describes the set of data classes 𝐶 and their associations. Every involved data object in the
process is an instance of such a data class. Each execution of a case in fCM evolves around
the case object. For the renovation example, the case class is the house as seen in Figure 2.
Each house can have a staircase and multiple apartments. For each apartment, a kitchen can
be built, paint can be applied once and tiles can be laid multiple times. The domain model
yields restrictions for the possible execution of the fragments, e.g., paint apartment can only be
executed once per apartment.




Figure 2: Domain model for the house renovation process.
Object behavior. In fCM, the concrete attribute values of a data object are abstracted as
states. During execution, states may change according to their allowed behavior specified
by state transition systems for each data class. It defines a set of states 𝑆𝑐 for each data class
𝑐 ∈ 𝐶 and possible state changes. The object behavior of the renovation process is displayed in
Figure 3. Each house instance can first be started before becoming finished. A staircase is first
init and can then be painted. An apartment can change its states from init to painted or tiles
laid, it can change between the latter two, before being finished. Tiles can be laid, paint is either
yellow or green, and kitchens can be installed.




Figure 3: Object behavior for the house renovation process.



Execution semantics. During the execution of a case, the case state defines the currently
available data objects, their links, and actions [5]. It consists of the tuple (𝑂, 𝐿, 𝐴). 𝑂 is the set
of all data objects, such that a data object 𝑜 ∈ 𝑂 is an instance of a data class 𝑐 ∈ 𝐶 in the domain
model. It is in a state 𝑠𝑐 ∈ 𝑆𝑐 of the classes’ state transition system. Furthermore, each data
object has a unique identifier 𝑖𝑑 ∈ 𝐼 𝐷.
   For the current state, 𝐿 holds all the links of the present data objects. A link is an unordered
pair of data objects that became associated during the case execution according to the domain
model. The possible actions for the current state are present in the set 𝐴. An action 𝑎 ∈ 𝐴 is the
instance of an activity defined in the fragments.
   During renovation, a case may be in a state, where there is a started house with the ID House
1. It is linked to two apartments with the IDs Apartment 1 and Apartment 2. Apartment 1 is
in init, while Apartment 2 is already painted yellow. Available actions include creating a new
apartment, laying tiles for both apartments, and painting Apartment 1 either yellow or green.

3.2. Goal models for fCM
Goal models that are within the scope of an fCM model can be used to derive recommen-
dations that support decisions during run-time [5, 22]. Goals are orders of objectives over
time. Objectives and goals can be formally defined as first-order logic statements and partial
orders [5].
   The set of all possible objectives Ω are all possible first-order logical statements over any
case state 𝑠 = (𝑂, 𝐿, 𝐴) [5]. An objective 𝜔1 ∈ Ω may express that in a state 𝑠, the Apartment 2
should have paint:
       𝜔1 ≡ ∃(𝑜1 , 𝑜2 ) ∈ 𝐿 ∶ 𝑜1 .𝑐𝑙𝑎𝑠𝑠 = 𝐴𝑝𝑎𝑟𝑡𝑚𝑒𝑛𝑡 ∧ 𝑜1 .𝑖𝑑 = "𝐴𝑝𝑎𝑟𝑡𝑚𝑒𝑛𝑡2" ∧ 𝑜2 .𝑐𝑙𝑎𝑠𝑠 = 𝑃𝑎𝑖𝑛𝑡
Another objective 𝜔2 states that a painted staircase should exist:
                       𝜔2 ≡ ∃𝑜 ∈ 𝑂 ∶ 𝑜.𝑐𝑙𝑎𝑠𝑠 = 𝑆𝑡𝑎𝑖𝑟𝑐𝑎𝑠𝑒 ∧ 𝑜.𝑠𝑡𝑎𝑡𝑒 = 𝑝𝑎𝑖𝑛𝑡𝑒𝑑
Goals are a partial order of temporally ordered objectives [5]. A partial order is a reflexive,
transitive, and antisymmetric relation over a set of elements. In the given definition, goals
are defined as a partial order over the set of objectives and via a set of pairs with directly
comparable objectives. The goal 𝛾1 orders the set of objectives {𝜔1 , 𝜔2 } partially with the
following specification:
                           𝛾1 = ({𝜔1 , 𝜔2 }, {(𝜔1 , 𝜔1 ), (𝜔1 , 𝜔2 ), (𝜔2 , 𝜔2 )}).
  Those goals can then be utilized to analyze the process model’s state space, i.e., all possible
behavior, for execution sequences that comply with the defined goals [5].

3.3. UML object diagrams
The unified modeling language (UML) [23] is a well-established standard [24]. In the fields of
computer science and business applications, UML is a frequently used modeling tool [25]. Class
diagrams are used most prominently, among others to define the domain of data-centric process
models like BAUML [6], OCBC [7], and also fCM [11].
   While class diagrams can represent the possible data objects for a process, UML object
diagrams may represent concrete data instances of such classes. Modelers can define concrete
data instances and their relations. In Figure 4, an object diagram represents an instance of the
fCM’s domain model (cf. Figure 2). A house with concrete attribute values is linked to two
apartment instances. They have concrete sizes and numbers of rooms.




Figure 4: A UML object diagram representing the instances of a house and two apartments.




4. Data-centric goal models
As defined in section 3, we consider goals to be an ordering of objectives over time, while
objectives are logical statements about the execution state of a process model. In the following,
we propose the notation of UML object diagrams to model objectives consistent with a given
data-centric process model. Dependency graphs are used to model the temporal ordering of
objectives. For both, we provide formal semantics that maps to the generic definition of goals
and objectives as presented in section 3.
4.1. Modeling objectives with UML object diagrams
Notation. Data-centric process models, like fCM, describe all involved data classes and
possible relations between them in a domain model as UML class diagrams. UML object
diagrams provide the opportunity to model instances of class diagrams at a certain point in
time. They express a configuration of instances of the data classes—the set of data objects and
their links.
   Objectives, on the other hand, are defined as logical statements over the set of data objects
and their links for a given point in time. The data objects and links relate to instances of the
domain model, i.e., a UML class diagram. The states of data objects relate to the object lifecycle
of their respective data class.
   Therefore, we utilize UML object diagrams to model data-centric objectives. The UML object
diagram acts as an instance of the UML class diagram in the process model. The behavior in an
fCM model abstracts from concrete attribute values and operates only on states. Therefore, we
also abstract from concrete values for object attributes in the UML object diagram. We utilize
the possible states of the data objects according to the object lifecycles as a substitute.
   For each data object, a modeler can specify the class of the object. This class relates to one
of the data classes 𝑐 ∈ 𝐶 of the domain model. Also, a unique identifier for the object can be
defined. Furthermore, the modeler may specify the state or states that the data object is allowed
to be in. The state attribute in the object diagram is a list of states 𝑆𝑐 for the specified class 𝑐.
The reasoning for such a list of states is that the object should exist and it should be in one of
the modeled states. If the list is empty, the object may be in any state.




Figure 5: The UML object diagram representing objective 𝜔3 .


   In section 3, the objectives 𝜔1 and 𝜔2 were already defined as a first-order logic statement. In
Figure 5, a new objective 𝜔3 is defined as a UML object diagram. It requires that there exists an
instance of the class House, which is linked to two apartments. One apartment shall have the
identifier ”Apartment 1” and the other ”Apartment 2”. For the first apartment, there shall exist
the kitchen ”Kitchen 1”, it shall be either painted or finished and have green paint and laid tiles.
The second apartment shall be painted.

Consistency with the data model. Since objectives define single case states, the UML
object diagram representing it must be consistent with the fCM. The object diagram must be a
valid instance of the domain model and its states must comply with the object lifecycles. The
following consistency guidelines ensure consistency between the different models.
    (i) Every data object must be an instance of a class in the domain model. Yet, not all classes
have to be represented.
    (ii) The links of objects must be coherent with the class diagram. Objects can only be linked
if their classes are associated. For instance, paint and tile instances must not be linked.
    (iii) Furthermore, the number of links in the object diagram must be coherent with the
multiplicities of the associations in the class diagram. The class House is associated with at
most four apartments. An objective connecting a house instance with five apartments would
violate our domain model.
    (iv) Lastly, all object states in the objectives must correspond to states of the object behavior
of the corresponding data class. For example, a house instance can only be in the states started
or finished. Like the first guideline, not all states have to be used.
    Even if these guidelines are met, it is still possible to model objectives that are impossible
to reach because the process model can never reach an according state. To detect this, model
checking can be utilized [5].

Formal representation. In order to utilize the proposed UML object diagrams for formal
verification of the fCM process model against a goal, we propose a representation of the object
diagrams as formal objectives. An objective is a first-order logic formula over an execution
state of the process model. This state 𝑠 holds information about the data objects 𝑂 and links 𝐿.
   For each data object node in the object diagram, a statement is created. It determines that
there exists an object 𝑜 ∈ 𝑂 in the set of data objects such that the class of 𝑜 is the same as the
object nodes. Considering 𝜔3 as specified in Figure 5, which requires the existence of a house,
is formalized as follows:

                                     ∃𝑜 ∈ 𝑂 ∶ 𝑜.𝑐𝑙𝑎𝑠𝑠 = 𝐻 𝑜𝑢𝑠𝑒

  If an identifier is specified in the object node, the identifier of 𝑜 needs to be the same as the
object node’s. In 𝜔3 , Kitchen 1 is required.

                          ∃𝑜 ∈ 𝑂 ∶ 𝑜.𝑐𝑙𝑎𝑠𝑠 = 𝐾 𝑖𝑡𝑐ℎ𝑒𝑛 ∧ 𝑜.𝑖𝑑 = ”Kitchen 1”

   For a data object node where a state is defined, the data object 𝑜 ∈ 𝑂 needs to have the same
state as specified in the node. In 𝜔3 , Apartment 2 is required to be in the state painted.

             ∃𝑜 ∈ 𝑂 ∶ 𝑜.𝑐𝑙𝑎𝑠𝑠 = 𝐴𝑝𝑎𝑟𝑡𝑚𝑒𝑛𝑡 ∧ 𝑜.𝑖𝑑 = ”Apartment 2” ∧ 𝑜.𝑠𝑡𝑎𝑡𝑒 = painted

  For an objective where multiple states are defined, the data object 𝑜 ∈ 𝑂 can have any of the
specified states. A disjunction of the condition per state is added to the formal expression. The
apartment ”Apartment 1” in 𝜔3 is required to be either painted or finished.

  ∃𝑜 ∈ 𝑂 ∶𝑜.𝑐𝑙𝑎𝑠𝑠 = 𝐴𝑝𝑎𝑟𝑡𝑚𝑒𝑛𝑡 ∧ 𝑜.𝑖𝑑 = ”Apartment 1” ∧ (𝑜.𝑠𝑡𝑎𝑡𝑒 = painted ∨ 𝑜.𝑠𝑡𝑎𝑡𝑒 = finished)

   For each link in the object diagram, a statement is created. It expresses that there exists a
link 𝑙 ∈ 𝐿, i.e., an unordered pair of data objects 𝑜1 , 𝑜2 ∈ 𝑂. The data objects must belong to the
specified classes in the object diagram. If an identifier is given for the object nodes, the link
must exist for the data object with the exact ID. If not, any object of the class is sufficient if it
satisfies the specified states. The link between the house and Apartment 1 in 𝜔3 is interpreted
as follows:
         ∃{𝑜1 , 𝑜2 } ∈ 𝐿 ∶𝑜1 .𝑐𝑙𝑎𝑠𝑠 = 𝐻 𝑜𝑢𝑠𝑒 ∧ 𝑜2 .𝑐𝑙𝑎𝑠𝑠 = 𝐴𝑝𝑎𝑟𝑡𝑚𝑒𝑛𝑡 ∧ 𝑜2 .𝑖𝑑 = ”Apartment 1”
   In summary, for each data object node and for each link in the UML object diagram, a first-
order logic statement is created. The objective is a conjunction of all these statements allowing
for representing 𝜔3 as a first-order logic formula.
   Objectives are first-order logic statements that are within the scope of the process model.
The same holds for the presented formal representation of UML object diagrams as objectives.
All formal expressions are made over the sets 𝑂 and 𝐿 of a case state. Given that the object
diagram is consistent with the case model, the object diagram only expresses constraints about
instances of data classes that are in the domain model. Also, it expresses conditions for the
states of those instances that are part of the according object lifecycle. Furthermore, all links in
the object diagram must be consistent with the domain model and the domain model describes
all possible sets of links in any 𝐿. Therefore, all expressions generated for the links in the object
model are in the scope of the state space as well.

4.2. Modeling goals with dependency graphs
A goal is defined as a combination of objectives over time. Reaching the objectives in a
certain order allows for fulfilling the goal. We propose to utilize dependency graphs to model
goals. Objectives are represented as nodes in the graph and their ordering is specified by their
dependencies.

Notation. Goals consist of objectives and define ordering constraints over them. A depen-
dency graph can be used to visualize this ordering. Dependency graphs are directed graphs and
defined as a tuple 𝐺 = (𝑁 , 𝐸) of nodes and edges. For our purpose, the available nodes are a
subset of all defined objectives 𝑁 ⊂ Ω. It must be finite and not empty. The edges are pairs of
nodes, i.e., pairs of objectives, 𝐸 ⊆ 𝑁 × 𝑁. In our context, dependency graphs must be acyclic to
model goals.
   Given the previously defined objectives 𝜔1 , 𝜔2 , 𝜔3 , and a new objective 𝜔4 ≡ ∃𝑜 ∈ 𝑂 ∶
𝑜.𝑐𝑙𝑎𝑠𝑠 = 𝐻 𝑜𝑢𝑠𝑒 ∧ 𝑜.𝑠𝑡𝑎𝑡𝑒 = finished, which requires a house to be finished. A goal is a temporal
ordering of those objectives. It can be denoted as a dependency graph. The goal 𝛾2 is one
possible goal for the four objectives and is visualized in Figure 6. The dependency graph has
a node for each considered objective 𝑁 = {𝜔1 , 𝜔2 , 𝜔3 , 𝜔4 } and the set of edges is defined as
𝐸 = {(𝜔1 , 𝜔2 ), (𝜔1 , 𝜔3 ), (𝜔2 , 𝜔4 ), (𝜔3 , 𝜔4 )}.

Consistency with the data model. Like individual objectives, goals must be consistent
with the domain model and the object lifecycles. The elements of the dependency graph itself
are not bound to these models. Yet, the dependencies that are defined between objectives may
violate the definitions in the process model. If the goal requires data objects to change from one
objective to the next in a way that is not supported by the model, it is not consistent.
Figure 6: The dependency graph representing the goal 𝛾2 .


   First, the state changes of data object instances between objectives must be within the
transitive closure of the object lifecycle. A data object instance can change its states only
according to the object lifecycle of its corresponding data class. Therefore, two objectives must
not require a data object to change its state in a way that is not supported by the object lifecycle.
For instance, a goal might require the house House1 to be finished and started in a later objective.
The fCM does not allow such behavior and this goal can never be satisfied.
   The links between data objects of two consecutive objectives must not contradict each other
with respect to the domain model. For example, a first objective 𝜔 specifies that the apartment
Apartment1 is linked to the house House1. But in 𝜔 ′ Apartment1 is required to be linked to
the house House2. The domain model requires apartments to be linked to at most one house.
Therefore, this goal would not be consistent with the domain model.

Formal representation. The dependency graph 𝐺 = (𝑁 , 𝐸) contains a set of objectives and a
set of edges that describe the ordering of two objectives. To interpret these dependency graphs
as goals, they can be formally represented as partial orders. A goal is a partial order of objectives
such that each objective in the dependency graph is an element of the partial order. For all
possible ordering constraints between two objectives in the dependency graph, the partial order
orders the two.
   Partial orders are transitive relations. Therefore, the dependency graph is interpreted as a
transitive reduction of all relations in the partial order, which formally defines the goal. For
each pair of objectives, where there exists a directed path in the dependency graph from the first
to the latter, there is an ordering in the partial order. The example dependency graph depicted
in Figure 6 can be formally represented as a partial order of its nodes representing objectives.

               𝛾2 = ({𝜔1 , 𝜔2 , 𝜔3 , 𝜔4 }, {(𝜔1 , 𝜔2 ), (𝜔1 , 𝜔3 ), (𝜔1 , 𝜔4 ), (𝜔2 , 𝜔4 ), (𝜔3 , 𝜔4 )})

For objective 𝜔1 there exists a path to every other objective. Therefore, the partial order contains
a pair from 𝜔1 to every other objective.
   Because the dependency graph is constrained to be acyclic, it always defines a finite set of
sequences of ordered objectives. The partial order defines two possible sequences of objectives
that are suitable to reach the goal: ⟨𝜔1 , 𝜔2 , 𝜔3 , 𝜔4 ⟩ and ⟨𝜔1 , 𝜔3 , 𝜔2 , 𝜔4 ⟩. The execution of the
process model hast to allow satisfying at least one of the two sequences to satisfy the goal.
   The proposed graphical goal models can be formally interpreted. Previous work shows that
such formal goals can be used to automatically derive decision support for knowledge workers
during run-time by [5, 22].
5. Prototypical implementation
We show how data-centric goals can be modeled visually as dependency graphs that order
objectives, while objectives can be modeled as UML object diagrams. Showing the technical
feasibility of the approach, we provide a proof-of-concept implementation1 to test and use. The
prototype extends the existing fCM modeling tool fCM-js [26], which offers design time support
and automated guideline checking while creating fCM models. This tool is extended with visual
modelers for creating objectives and goals.
   The prototype allows for modeling multiple objectives and combining them into a goal. As
previously elaborated, adherence to specific guidelines is imperative to maintain consistency
across all diagrams. To address this requirement, we have incorporated interconnections
between the modeler, the domain model, and the object lifecycles in our implementation.




Figure 7: The objective 𝜔3 modeled in the objective modeler.


   The objective modeler allows the modeling of UML object diagrams. In Figure 7, the previously
introduced objective 𝛾3 is modeled in the prototype. As objects are derived instances of classes,
users may select classes that are specified in the data model of the fCM when creating a new
object. If a new class is created in the object modeler, it is automatically incorporated into the
domain model. Similar functionality applies to the selection of states, which can be determined
after class selection. The available selectable states are consistent with the corresponding object
lifecycle associated with the referenced class. Additional to the object’s states, the user may
assign a name to each object, which remains exclusive to that particular object within the given
objective. This allows referencing data objects across objectives.
   Users can model multiple objectives that can be combined in the dependency modeler illus-
trated in Figure 8. It supports modeling a dependency graph of objectives that correspond to
specific object diagrams in the objective modeler. Users can model the temporal ordering of the
previously defined objectives by adding the desired dependencies between objectives.
   Based on the defined goal model, the prototype can automatically generate a state space
query, which can be used to derive recommendations [5]. Such recommendations return a
Boolean for each next action indicating whether it allows reaching the goal.

1
    Source and Documentation https://github.com/bptlab/fCM-design-support/tree/state-space-queries
Figure 8: The goal 𝛾2 modeled in the dependency modeler.


6. Discussion and conclusion
Planning and goal modeling are essential in knowledge-intensive processes. Goals are a basis
to provide decision and planning support for running process instances. We provide the means
to model data-centric goals for fCM models graphically. Goals consist of objectives. Objectives
express constraints over possible future execution states and can be modeled with UML object
diagrams. Goals are a temporal ordering of objectives and can be defined as dependency graphs.
We provide a formal interpretation of these models that can be utilized to derive decision support
during run-time. Our approach is evaluated by a prototypical goal modeling tool.
   The presented work has some limitations. In contrast to prior formal definitions of goals,
UML object diagrams are less expressive than any first-order logic statement about a case state.
Still, object diagrams are an established and well-known modeling technique and are more
human-readable than first-order logic statements. In the presented object diagrams, attribute
values in object diagrams are abstracted as data object states. In the future, a mapping of
attribute values to data states could be beneficial for the practical usage of the presented goal
models. The prototype is currently limited in its ability to derive decision support. Future
implementations should extend the current functionality.
   The benefit of the graphical goal models over formal expressions should be empirically
evaluated in the future. Furthermore, the applicability as input for automated planning in BPM
should be investigated. Also, the combination of the presented goal models with concepts of
goal-oriented requirements language could allow for even more expressive goal models. Future
work should investigate the application of the presented approach to different practical use
cases resulting in domain-specific data-centric goal models.
   The presented graphical goal models are based on UML object diagrams and can therefore
be applied to any process model with a UML class diagram as a domain model like BAUML,
OCBC, or BPMN. Consequently, the respective modeling techniques can now be extended with
graphical goal modeling for running process instances.
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