Process modeling techniques for information systems Mark Steunenberg University of Twente

Drienerlolaan 5 7522 NB Enschede +(31) 6 11 51 05 31

referaat@marksteunenberg.nl

ABSTRACT This research aimed to make a comparison between several process modeling languages and their proficiency at modeling value networks and value shops. The research started out with deriving the BWW ontology from existing literature and modifying it for value networks and value shops. Then two comparisons have been made. One from the ontology towards various process modeling languages so we could see what process modeling language have the largest ontological completeness (ARIS, E3Value and BPMN) and one comparison from the languages with the ontology to reflect on the ontology used.

Keywords Value shops, Value networks, Process Modeling, E-Business, BWW model

1. INTRODUCTION There has been a lot of research towards modeling techniques and how they give a realistic view of the business process they are modeling. At present day there are lots of different modeling techniques and each has his own benefits. In the IT world there are always new developments. There are often new technologies in the market, which leads to new possibilities and later on, new methodologies for modeling a business process. [14] New online businesses sometimes have special needs. They don’t use a standard value creation process but gives the users that use the product special attention. These business concepts are often modeled based on the value shops or/and value networks [16] principle. Modeling such concepts often result in complex diagram which are hard to understand for anyone but the expert [14]. This paper will show a comparison how the most common process modeling languages and their proficiency at these value networks and value networks. Production processes are usually displayed in a linear process. As researched by Porter the value creation logic can best displayed in a value chain model [10]. In this process every step has a specific action that is being added to the intermediate product. Every step gives the intermediate product more value. There are several core elements that all add their value to the product. The support elements enable the production process.

The Figure 1 displays an example of the value chain model. The top horizontal elements are the supporting activities, while the lower elements are the core elements of the company.

Mar

gin

Firm Infrastructure

Human Resource Management

Technology

Procurement

Inbound logistics Operations Outbound

logisticsMarketing &

Sales Service

Margin

Figure 1: Value chain model

A value shop is a more complicated process. It doesn’t work with creating value from raw materials but on solving unique customer problems. Services like medicine and consulting are typical value shop examples. The five main steps in this process are problem acquisition, problem solving, choice of problem solutions, execution chosen solution and evaluation. If after the evaluation the problem isn’t adequately fixed then the process repeats itself. This iterative and unique nature makes it hard to model a value shop [16]. A simple value shop model is displayed in figure 2

Choice

Problem solving Execution

Problem finding and acquisition

Control & Evaluation

Figure 2: Example value shop

A value network is a process in which the value is created by a network. A clear example of this is a telephone company. Here a set of users make use of a service that provides interaction between them. The value is created by facilitating the use of the network for the user. The users themselves are part of the service or product. The facilitating nature of this model makes it hard to model where the value is created because of the large amount different elements involved and the two way relationships within the network. [16] An example is shown in Figure 3.

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Figure 3: Example value network

1.1 Outline This thesis consists of first defining the research questions in four parts that each together add up to making the comparison between modeling techniques and their criteria. Then the methods of research are briefly discussed. In section four the ontology is introduced and expanded to answer the second research question. In section five two cases are explained which help understand the introduction of all tested modeling techniques which is done in section six. Section seven will make the actual comparison between the criteria and the techniques. Important remarks and remarkable results are also noted here. The reflection backwards from the modeling languages towards the ontology is done in section eight. All important conclusions done in this thesis will be repeated in section nine. Finally the thesis will concluded with possible options for future work.

2. RESEARCH QUESTIONS To ensure that there is a structured and methodical approach to the research the problem statement is split in five different research questions. Combining all these research questions gives all the information needed to judge which modeling technique is the best to model a value shop or value network. The first step will be a literature research towards getting a set of techniques that claim to be well suited for modeling value shops and networks. The end result of this research question is to get a better overview of all the techniques and to get a shortlist models to be used.

• What modeling techniques are available for modeling value shops and networks?

Criteria can be derived to measure if an element can be modeled in a specific language. The next research question aims to get from a list of specific elements and cases towards a sensible list of criteria. For these criteria an ontological approach similar to the one used by Peter Green and Michael Rosemann on ARIS will be used [15]. We will expand the BWW model with specific elements for value shops and value networks so the comparison will be relevant.

• What criteria can be derived to rate a modeling technique from the specific elements used in value shops / value networks

The third step is to compare all the modeling techniques from the first step to the criteria. This allows us to quantify how well suited each of the modeling technique are for our criteria.

• How does each of the modeling techniques measure up to those criteria?

Combining the knowledge of modeling techniques and how they can be measured using the ontology it is possible to learn and derive a better set of criteria

• Are the criteria used to measure the modeling techniques accurate?

3. METHODES OF RESEARCH Within this research there are two main knowledge questions. The first centers around which process modeling techniques are available that are able to model value shops or value networks. For this case a literature research will be conducted. Books and papers that are currently trying to model value shops and value networks will be checked and noted with which languages these are modeled. Since value shops and value models are commonly used it is assumed that there are enough modeling techniques to make a decent comparison. The keywords that will be used in the search are: value shop, value network, e-business model and various on this term. The most relevant papers found with these searches have also their referenced literature examined to ensure that there is no gap of missing literature. When a list of languages has been composed, a verification step will be taken for all the modeling guidelines of these languages to see if they claim that they can model the value shops and value models. Often the exact use of the modeling language is slightly adapted due to learning errors, bad practices, or the borrowing of convenient elements from other languages. To ensure that there are none of these adapted models in our research the original standard will be used. The second knowledge question is what criteria can be used to test if these modeling techniques are adequate to use and to find an ontology on which these criteria can be tested. This question is answer by in the next section

4. METHODOLOGY Before a comparison can be made between the criteria and how the different modeling techniques can represent that, first an ontology should be defined. This ontology then is the basis for the criteria. Ontology can best be described as the set of concepts that should be represented within in a modeling technique. How a modeling language represents the ontological concept is called the grammar of the language. [18] There are cases in which the ontology is unable to match with the actual model. Depending on the type of mismatch the following terms are used: 1. Ontological Incompleteness. This exists unless there is at least one grammatical construct for each ontological construct. 2. Ontological Clarity is determined by the extent to which the grammar does not exhibit one or more of the following deficiencies:

• Construct Overload exists in a grammar if one grammatical construct represents more than one ontological construct.

• Construct Redundancy exists if more than one grammatical constructs represents the same ontological construct.

• Construct Excess exists in a grammar when a grammatical construct is present that does not map into any ontological construct.

Green and Rosseman use the Bunge-Wand-Weber (BWW) model to judge several process modeling techniques. This model will provide us with an ontological basis to make the comparison.

4.1 BWW MODEL The Bunge-Wand-Weber (BWW) model is list of ontological constructs. If every ontological construct can be can be used by a grammatical construct within the modeling technique then the technique would be ontological complete. Within the BWW model the ontological constructs as shown in Table 1 are present [5]

Table 1: BWW standard elements Thing A single unit

Property A attribute of a unit

Class A set of things with a single common property

Kind A set of things with more common properties

State The value of all the attributes of a unit makes the state

Conceivable state space The set of all states reachable

State law A state law that restricts the value of properties

Lawful state space The set of all states that is deemed lawful by nature or government laws

Conceivable event space All possible events that can occur in a thing

Transformation Changing from one state to another state

Lawful transformation Transformations that are compliant with laws

Lawful event state The set of all events in a thing that are lawful

History Chronologically ordered states of a thing

Coupling One thing that acts on another thing

Acts on An acts on relation that effects things

System A strongly correlated set of things

System composition All the things in the system

System environment Things that are not in the system but interact with things in the system

System structure The couplings within the system and from the system with the environment

Subsystem A system that is a subset of another system

Decomposition A complete set of subsystems and things in a system.

Level structure The partial order of subsystems in a decomposition

External event An event that arises by virtue of something in the environment

Stable state A state in which a thing stays unless forced by an external event

Unstable state A state that that can be changed by an internal event

Internal event An event that arises by virtue of something in the thing, subsystem or system

Well-defined event A event in which the subsequent state always can be predicted given that the prior state is known

Poorly-defined event A event in which the subsequent state cannot be predicted given that the prior state is known

Since we will use the BWW model to assert two specific situations, we will add criteria that test these value network and value shop situations. These are shown in Table 2. This list of criteria may not be final but will be reviewed in more detail in section 9 where the ontology elements will be evaluated based on the grammar of the languages. If a language has specific elements that are proficient at modeling value networks and value shops but aren’t mapped into an ontological element these are mentioned there. This model with its added elements is also the answer to the second research question: What criteria can be derived to rate a modeling technique from the specific elements used in value shops / value networks

Table 2: Added elements to the BWW model Iteration The coupling of things in a

circle

Direction Which way a state transition can go.

Value port A unit that denotes a exchange in value between objects, with a direction.

5. CASES When explaining specific problems within a certain diagram style the problem arises that this can become an abstract story. To combat this two specific cases have been made up so that with every problem an example can be given.

5.1 Value shop case An example of a value shop case is Innocentive. (website http://innocentive.com/) Innocentive is a company where problem owners can post their problems with a detailed description of what they want to have delivered. A large user base of various experts will then try to solve the problem. The one with the best idea wins a money reward ranging from $1500 to $1 million. The iterative process occurs when the company sees that certain people go towards a good direction. The company tell the other problem solvers that this direction the desired. This way the problem ‘locks in’ towards a good solution direction. This iterative approach to solve a problem is characteristic for a value shop.

5.2 Value network case For the problems that can be modeled using a value shop we will use the example of an online social network like Hyves. Hyves has members on their site who each create their own profile. They can send messages towards each other. The value created for the company is amount of people who are a member of the profile site. More members, who are part of the site, create a larger incentive for other people also join because you can view more profiles and send messages to more people [7]. The revenue is generated because the network generates advertising revenue from each of the visitors towards the site. It is important for them that people check back towards the site frequently. Also several people make use of extra options for which a small fee is charged.

6. MODELING TECHNIQUES This section describes which modeling techniques claim to be able to model value shops and networks. For this research a literature research has been conducted. This is an adequate solution since we are interested in what models are actually used. Using this search we have come to following modeling languages. When working with modeling techniques often deviations of the original modeling technique are used. To ensure that we use the original modeling technique the standards of the various languages have been used. A list of these is below:

• Standard UML activity diagrams [13]

• Petri nets [6]

• e3 value [4]

• IDEF0 [17]

• REA ( Resource-Event-Agent ) [3]

• BPMN (Business Process Modeling Notation) [19]

• ARIS (Architecture of Integrated Information Systems) [5]

• BPEL (Business Process Execution Language)[8] This list is not all inclusive but is gathered as described in section 3. It does however aims to be a list of all commonly used modeling techniques within value shops and value networks, but with this list the first research question is answered.

6.1 UML activity diagrams The UML activity diagram is a well know diagram style. The initial development started in the ’90 and the first version was adopted as a standard in 1997. The current UML standard is 2.0. UML has only a few elements which makes it an easy diagram to understand. This is also one of the main drawbacks of the language, since all situations need to drawn with the elements available. It has activities, decisions, splits and joins, initial and final states. The use of synchronous concurrency is difficult to model within this diagram but can be done using a sync state. [2]. In Figure 4 the Innocentive example is used to illustrate UML. A person comes to Innocentive with a problem, it is made public and two things can happen, or a first direction towards a solution is found, or nobody responds to it.

Figure 4: An example of the Innocentive case in UML

6.2 Petri nets Petri net is very different from the other languages in the sense that it is execution language and not really business modeling language. The language is however often used to model them [1]. Another difference with the other modeling techniques is that it is based on a mathematical basis [6]. This allows that certain factors such as reachability and liveness can simply be calculated. An example is shown in figure 5. Petri net contains elements such as places, transitions, arcs and tokens. Places are modeled as circles and can contain tokens. The location of the tokens represents the state of the system. Arcs connect places and transactions so that the order of workflow can be shown.

Person having a problem

Posting it on Innocentive

Making the problem public

Assessment of solution

Someone posting a solution

Figure 5: An example Petri net

6.3 E3 value The E3 value modeling technique is based primarily on connecting organizational units. The network factor is really important within this tool. It was researched in 2001 by Jaap Gordijn and Hans Akkermans [4]. The basic elements here are organizations, interfaces and value ports where an exchange of information or goods takes place. The strong point of this modeling technique is that it is clear where elements are exchanged. . The example in figure 6 shows a user visiting the Hyves website and receiving an update with all the new information since his last visit. When he receives this update of new information there is also an advertisement shown. This

gives Hyves money from the web advertiser. Since both the web advertiser and the user interaction are on the same value interface it is implied that this happens together in one exchange.

Figure 6: An example e3value diagram

6.4 IDEF0 IDEF0 belongs to the IDEF series of modeling techniques. IDEF0 focuses on the highest level of modeling. It deals with the decisions, action and activities that happen within the business process. [17]. It was developed in 1981 by Integrated Computer Aided Manufacturing from the U.S. Air force. The buildup is quite simple since it only has two main elements, blocks and arrows. Blocks denote function within a system or by a user. The arrows denote an exchange of data. In figure 7 you see someone looking on the hyves website, to which hyves finds a suitable advertisement, and showing it on the webpage where the user is brought to receive his updates.

Figure 7: An example IDEF01 diagram

6.5 REA The Resources, Events, Agents, or short REA, is derived from the accounting world. It was made to deal with assets being sold to a costumer. From these origins duality is often included within the modeling technique. This means that goods or services always relates to the opposing goods or services [3]. A REA model has four different elements: Resources, events, agents and actions. Resources are goods, money, services etc. Events are shown by a diamond shape and depict actions such as pays and delivers. Agents are the people making use of the system, in this case the advertising company and Hyves. The last are the activities. In this case the companies have just two activities: showing advertisements to the user and sending

invoices. In figure 8 is a REA diagram shown using the Hyves case. Note the duality between ‘advertisement shown to user’ and an ‘invoice’.

Figure 8: An example REA diagram.

6.6 BPMN BPMN stands for Business Process Modeling Notation and is a modeling technique based on UML activity diagrams. It was adopted as a standard in 2006. The main difference is that there is no way of modeling data, organizational and functional breakdowns since those elements are often not needed in a business process [19]. By excluding them it forces the user to use a higher level of abstraction. The modeling techniques has quite a few elements such as events, activities, gateways, sequence flows, swim lanes and data objects. In figure 9 a very simple diagram is shown. .

Figure 9: An example BPMN diagram

6.7 ARIS ARIS is a special approach to model a business. It builds on a five different level of modeling who all are integrated on the middle level. At the top you have the organization view where all the actors in there organizational units are modeled. Then on the sides you have the data and function view that both are self explanatory. These three are all connected to the middle control

view where it is modeled who (organization) uses what data for what function. Sometimes the bottom view is also used. It is the resource view where all the IT resources that are being used are shown, but sometimes this is also taken for granted. In figure 10 you see an example of an ARIS process diagram. The Innocentive example is used. A person is having a problem, which is an event. Then the action posting it on Innocentive is shown to be supported by an IT system, namely the Innocentive problem management system

Figure 10: An example ARIS process diagram

6.8 BPEL BPEL stands for Business Process Execution Language, often also named as Web Services Business Process Execution Language. It is an executable modeling technique for modeling web processes. With the high amount of data provided by many different resources in the current web based world IBM and Microsoft decided to work together to develop a standard on modeling business processes in an online environment [8]. In 2003 the first version was released, the current version 2.0 is used in this report. The fact that it is an executable model means it can generate workable xml code. A figure of the BPEL program couldn’t be provided since there was only access to a free textual modeling tool. BPEL has elements such as variables and activities just like many programming languages

7. COMPARISON Already a few comparisons have been made by literature like the ARIS comparison by Greenman [5], the UML comparison by Opdahl [9], the Petri net comparison by Recker [11] and the BPMN comparison by Recker as well [12]. These comparisons have been used in this thesis. The complete comparison is show in Appendix A. The comparisons that are done new in this

paper are explained in more detail in Appendix B. These are E3 value, IDEF0, REA and BPEL. The mapping is done by gathering a full list of all the elements within a language and comparing their description and use towards the BWW description. When a match is found it is added in the list. It did occur multiple times that an element in BWW is modeled by more elements in the specific modeling technique. As described in section 4 this is called construct redundancy. All the important notions from this system are shown below:

1. The system structure is not correctly modeled by any of the modeling techniques.

2. State modeling seems to be difficult for IDEF0, BPMN and BPEL

3. ARIS, E3Value and BPMN have rated the most ontological completeness.

4. REA has the lowest ontological completeness. This is because it has difficulties defining exact states and has no way in defining the system structure as whole or separate parts of it.

5. If in a modeling technique a thing can’t hold properties then it is impossible to define a state.

This comparison also answers the third research question.

8. REVIEWING THE MODEL The first important note from the comparison is that even among eight modeling techniques there was no modeling technique that could model the system structure. The definition of the system structure is as followed: “The couplings within the system and from the system with the environment”. This could also be interpreted as all the couplings in the system and objects they edit. In most cases this is the entire set of all elements in the system, or easier said the entire canvas on which the diagram is drawn. Therefore I propose to loosen the definition of the system structure. The second important note is that ontological redundancy can occur quite often, and according to the definition these elements are not all needed. Often the different elements do have a subtle difference. Deletion or merging of the ‘double’ elements in the modeling techniques would have the undesired effect that information could not be shown in the diagram. Instead the level of detail within the BWW-model seems to define what elements are considered double. An example is an Internal or External event which can be considered the same or different depending on level of detail. This means that there is room for improvement within the model but for the most part it does give a good indication of the possibilities of a modeling technique. This answers our fourth and last research question

9. CONCLUSION If it is know what types of ontology are needed for a specific modeling task the table in Appendix A can be used lookup what modeling technique has the ability to model all these ontological constructs. Furthermore from the comparison it is shown that ARIS, E3 Value and BPMN have a good ontological completeness. These languages should be better at modeling value shops and value networks Lastly there are a few points of improvement towards the BWW-model. The term system structure is defined in such a

way that no of the eight modeling techniques matches it. I propose to loosen this definition. The level of detail seems to work through in the rating of the modeling techniques. This is an undesired effect.

10. FUTURE WORK For future work the BWW model should be thoroughly examined by doing more analysis of languages back to the BWW-model. There is lot of room for improvement of the BWW-model on the field of value shops and value models. This improvement could be reached by reverse engineering models of value shops or value networks towards the BWW-model. Furthermore this has been a limited study. Due to the amount of modeling techniques that have been researched (eight) not all techniques have got an in-depth review. This is especially the step from the language back to the model has room for improvement. Finally it is valuable to add more languages to this review. The languages that are now examined are the most common used languages today. There are however new languages emerging and there are also a lot of languages not examined. These all can be included in the BWW comparison as well.

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petri-net-based workflow management system Kluwer [2] Dumas M, Hofstede AHMt (2001) UML Activity

Diagrams as a Workflow Specification Language Lecture Notes in Computer Science 2185/2001

[3] Geerts G, McCarthy W (2000) The Ontological Foundation of REA Enterprise Information Systems

[4] Gordijn J, Akkermans H, Vliet Hv (2000) Business Modelling Is Not Process Modelling Lecture Notes in Computer Science 1921: 40-51

[5] Green P, Rosemann M (2000) Integrated process modeling: an ontological evaluation Information Systems 25: 73-87

[6] Hee KMv (1994) Information systems engineering: a formal approach. Cambridge university press

[7] Katz ML, Shapiro C (1994) Systems Competition and Network Effects The Journal of Economic Perspectives 8: 93-115

[8] OASIS (2007) Business Process Execution Language Version 2.0. In: Editor (ed)^(eds) Book Business Process Execution Language Version 2.0. OASIS, City

[9] Opdahl AL, Henderson-Sellers B (2002) Ontological Evaluation of the UML Using the Bunge-Wand-Weber Model Springer 1: 43-67

[10] Porter ME, Millar VE (1985) How information gives you competitive advantage Harvard Business Review 63: 149-160

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[12] Recker J, Indulska M, Rosemann M, Green P (2005) Do Process Modelling techniques get better? A comparative ontological analysis of BPMN Australasian Conference on information systems 16

[13] Rumbaugh J, Jacobson I, Booch G (2005) The Unified Modeling Language Reference Manual. Addison-Wesley, Boston, Massachusetts

[14] Smith H, Fingar P (2003) Business Process Management: The Third Wave. Meghan-Kiffer Press

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12. APPENDIX Appendix A: The comparison between the adapted BWW and 8 modeling languages

Table 3: Comparison between adapted BWW and the 8 languages UML Petri nets E3 value IDEF0 REA BPMN ARIS BPEL

Thing Y Y Y Y Y Y Y -

Property Y - Y - - - Y Y

Class Y Y Y Y - Y Y Y

Kind Y - Y Y - Y Y -

State Y Y Y - - - Y Y

Conceivable state space

- - Y - Y - - -

State law - Y Y - Y - Y -

Lawful state space - Y Y - Y - - -

Conceivable event space

- - - Y Y - - -

Transformation Y Y Y - - Y Y -

Lawful transformation

Y - - - - Y Y -

Lawful event state - - - Y Y - - -

History Y - - - - - - -

Coupling Y - Y Y Y Y Y Y

Acts on Y Y Y Y Y Y - Y

System Y - Y - - Y - Y

System composition Y - Y - - Y Y -

System environment - - - Y - Y - Y

System structure - - - - - - - -

Subsystem - -- - Y - Y Y -

Decomposition - - - Y - Y - -

Level structure - - - Y - Y Y -

External event Y - Y Y - Y Y Y

Stable state Y - - - Y - Y -

Unstable state Y Y - - - - Y -

Internal event Y Y Y Y - Y Y Y

Well-defined event Y Y Y Y Y Y Y Y

Poorly-defined event - - - - - Y - -

Iteration Y Y - - - - Y -

Direction Y Y Y Y - Y Y Y

Value port - - Y Y Y Y - -

Appendix B: Comparing BWW with various modeling techniques

Table 4: Comparing BWW with E3 value BWW Elements E3 Value

Thing A single unit Value activity, Actors

Property A attribute of a unit Attribute_Name

Class A set of things with a single common property Value activity, Actors

Kind A set of things with more common properties Market segment

State The value of all the attributes of a unit makes the state Set of all value objects

Conceivable state space

The set of all states reachable Set of value exchanges

State law A state law that restricts the value of properties Set of value exchanges

Lawful state space The set of all states that is deemed lawful by nature or government laws Set of value exchanges

Conceivable event space

All possible events that can occur in a thing -

Transformation Changing from one state to another state Value exchange

Lawful transformation

Transformations that are compliant with laws -

Lawful event state The set of all events in a thing that are lawful -

History Chronologically ordered states of a thing -

Coupling One thing that acts on another thing Value exchange

Acts on An acts on relation that effects things Value exchange

System A strongly correlated set of things Market segment

System composition All the things in the system Value activity, Actors, value interfaces, value exchanges

System environment Things that are not in the system but interact with things in the system -

System structure The couplings within the system and from the system with the environment

-

Subsystem A system that is a subset of another system -

Decomposition A complete set of subsystems and things in a system. -

Level structure The partial order of subsystems in a decomposition -

External event An event that arises by virtue of something in the environment Value port

Stable state A state in which a thing stays unless forced by an external event -

Unstable state A state that that can be changed by an internal event -

Internal event An event that arises by virtue of something in the thing, subsystem or system

Start Stimulus

Well-defined event A event in which the subsequent state always can be predicted given that the prior state is known

Start Stimulus / End Stimulus / Value exchange

Poorly-defined event A event in which the subsequent state cannot be predicted given that the prior state is known

-

Iteration The coupling of things in a circle -

Direction Which way a state transition can go. Value port direction

Value port A unit that denotes a exchange in value between objects, with a direction. Value port

Table 5: Comparing BWW with IDEF0

BWW Elements IDEF0

Thing A single unit Box

Property A attribute of a unit -

Class A set of things with a single common property Box

Kind A set of things with more common properties Box

State The value of all the attributes of a unit makes the state -

Conceivable state space

The set of all states reachable -

State law A state law that restricts the value of properties -

Lawful state space The set of all states that is deemed lawful by nature or government laws -

Conceivable event space

All possible events that can occur in a thing Arrow

Transformation Changing from one state to another state -

Lawful transformation

Transformations that are compliant with laws -

Lawful event state The set of all events in a thing that are lawful Arrow

History Chronologically ordered states of a thing -

Coupling One thing that acts on another thing Arrow

Acts on An acts on relation that effects things Arrow

System A strongly correlated set of things -

System composition All the things in the system -

System environment Things that are not in the system but interact with things in the system Boundary Arrow

System structure The couplings within the system and from the system with the environment

Arrow

Subsystem A system that is a subset of another system Decomposition Structure

Decomposition A complete set of subsystems and things in a system. Decomposition Structure

Level structure The partial order of subsystems in a decomposition Decomposition Structure number

External event An event that arises by virtue of something in the environment Boundary Arrow

Stable state A state in which a thing stays unless forced by an external event -

Unstable state A state that that can be changed by an internal event -

Internal event An event that arises by virtue of something in the thing, subsystem or system

Internal Arrow

Well-defined event A event in which the subsequent state always can be predicted given that the prior state is known

Arrow

Poorly-defined event A event in which the subsequent state cannot be predicted given that the prior state is known

-

Iteration The coupling of things in a circle -

Direction Which way a state transition can go. Arrow Direction

Value port A unit that denotes a exchange in value between objects, with a direction. Arrow subtext

Table 6: Comparing BWW with REA

BWW Elements REA

Thing A single unit Resources, Agent, Action and Event

Property A attribute of a unit -

Class A set of things with a single common property -

Kind A set of things with more common properties -

State The value of all the attributes of a unit makes the state -

Conceivable state space

The set of all states reachable Event

State law A state law that restricts the value of properties Event

Lawful state space The set of all states that is deemed lawful by nature or government laws Event

Conceivable event space

All possible events that can occur in a thing The combination of actions with events

Transformation Changing from one state to another state -

Lawful transformation

Transformations that are compliant with laws -

Lawful event state The set of all events in a thing that are lawful Event

History Chronologically ordered states of a thing -

Coupling One thing that acts on another thing Duality

Acts on An acts on relation that effects things Action

System A strongly correlated set of things -

System composition All the things in the system -

System environment Things that are not in the system but interact with things in the system -

System structure The couplings within the system and from the system with the environment

-

Subsystem A system that is a subset of another system -

Decomposition A complete set of subsystems and things in a system. -

Level structure The partial order of subsystems in a decomposition -

External event An event that arises by virtue of something in the environment -

Stable state A state in which a thing stays unless forced by an external event Event

Unstable state A state that that can be changed by an internal event -

Internal event An event that arises by virtue of something in the thing, subsystem or system

-

Well-defined event A event in which the subsequent state always can be predicted given that the prior state is known

The combination of actions with events

Poorly-defined event A event in which the subsequent state cannot be predicted given that the prior state is known

-

Iteration The coupling of things in a circle -

Direction Which way a state transition can go. -

Value port A unit that denotes a exchange in value between objects, with a direction. Duality

Table 7: Comparing BWW with BPEL BWW Elements BPEL

Thing A single unit -

Property A attribute of a unit Variables

Class A set of things with a single common property Properties Correlation Sets

Kind A set of things with more common properties -

State The value of all the attributes of a unit makes the state Multiple variables

Conceivable state space

The set of all states reachable -

State law A state law that restricts the value of properties -

Lawful state space The set of all states that is deemed lawful by nature or government laws -

Conceivable event space

All possible events that can occur in a thing -

Transformation Changing from one state to another state -

Lawful transformation

Transformations that are compliant with laws -

Lawful event state The set of all events in a thing that are lawful -

History Chronologically ordered states of a thing -

Coupling One thing that acts on another thing Partner link

Acts on An acts on relation that effects things Partner link

System A strongly correlated set of things Partner link

System composition All the things in the system -

System environment

Things that are not in the system but interact with things in the system Event handlers

System structure The couplings within the system and from the system with the environment -

Subsystem A system that is a subset of another system -

Decomposition A complete set of subsystems and things in a system. -

Level structure The partial order of subsystems in a decomposition -

External event An event that arises by virtue of something in the environment Activity, Structured Activities

Stable state A state in which a thing stays unless forced by an external event -

Unstable state A state that that can be changed by an internal event -

Internal event An event that arises by virtue of something in the thing, subsystem or system

Activity, Structured Activities

Well-defined event A event in which the subsequent state always can be predicted given that the prior state is known

Activity, Structured Activities

Poorly-defined event

A event in which the subsequent state cannot be predicted given that the prior state is known

-

Iteration The coupling of things in a circle -

Direction Which way a state transition can go. Activity, Structured Activities

Value port A unit that denotes a exchange in value between objects, with a direction. -