Towards the Corporate Semantic Process Web
1 Semtation GmbH, Bredower Str. 145
14612 Falkensee, Germany
2 Beratung im
Netz, Merkurstrasse 17,
14482 Potsdam, Germany
Abstract. The article gives an overview on how Business Process Modeling can be made more efficient and reusable by applying some simple ideas borrowed from the new concept of the "Semantic Web"  to process modeling. The main idea of the Semantic Web is to form a world wide web of formal models in addition to the existing web of text. This concept is applied to process modeling by relating ontologies  and process elements. By the use of ontology-based process modeling tools such as SemTalk , reference models will be built and used in a decentralized manner. Integration with the MS-Office Suite enables even casual users to contribute to the Corporate Semantic Process Web in a way that their knowledge will become beneficial for their company. We are demonstrating how this concept can be used by discussing some real world examples such as localization of models, reference models for E-Government and process templates for MS-Project.
1 Separation of Ontologies and Processes
Using traditional Business Process Modeling tools one can enter arbitrary names for activities and objects in a process. Especially if the business is being modeled in parallel by multiple persons, external consultants or for more than one department at a time, the result will be a redundant and inconsistent model, which is hardly maintainable. This effect is nearly independent from the multi-user capabilities of the modeling tools being used. Even a central repository does not ensure consistency of the model on its own, as long as the internal organization of the model is not coordinated. Some modeling methodologies have a strict level of hierarchies and well defined interfaces between main process components. Applying them might help in specific situations . In general such a black-box strategy helps to reduce the problem space into sub problems. The major disadvantage of this approach is, that the overall model can not be analyzed as a whole anymore because of a lack of common terminology in the sub models.
The described problem becomes critical as soon as you localize such a model to foreign languages. A lot of the used nouns will be recognized as synonyms. These are multiple words with the same meaning. Even worse, but quite common cases are homonyms. These are model objects, which refer to different meanings for the same term. The solution is quite obvious as soon as you investigate existing models: The names of the activities are very often a composition of a verb and a noun such as write business plan. Virtually all used activity names can be created using this simple scheme. Such an 'object-oriented' wording cannot be realized in every interview situation, but it can be trained with users easily. Even some object-oriented reengineering of the model after the interview may be accomplished if there is some tool support for this. Beyond this there is another lesson learned from object-oriented modeling in software engineering. It is always a good idea to use as few flexions as possible. Especially singular and plural forms of a noun should not be mixed.
Fig. 1. Recycling tool for process models
A major German pharmaceutics company got aware of these problems with legacy models. In order to preserve the taken investments in process modeling a database was set up, which helped to systematically clean object and task names in the model (see fig. 1). This is done by creating a single dictionary (serving as a glossary for future use). The renaming of the objects in the real model is done automatically. After these steps the translation of large models to several European languages could be made with reasonable effort.
In the next chapters we are explaining our approach for ontology-based process modeling in detail. Using the approach, which mainly is focused on reusability, prevents the models from experiencing the translation problem as a side effect.
1.1 Composition of task names
Modelling tools, which have support for an ontology-based approach such as SemTalk, explicitly use objects and their methods to construct elements of the model and to keep them consistent. write business plan and review business plan are tasks referring to the same object named business plan. In case business plan is going to be renamed all tasks and their occurrences on diagrams are going to be updated. There are two ways how to build the ontology and the process. Following the bottom-up approach classes and verbs are found while creating the process. The top-down approach favours to create an ontology first as a library and use it afterwards while creating the actual process.
One important aspect is that the verbs (or "methods") are going to be inherited from general classes to the more specialized classes. Consider a task like review plan and the fact that a business plan is a specialization of (or subClassOf) a plan. For the task review business plan the class business plan inherits the verb review from the more general class plan. Object-oriented specialization helps to find the right layer of abstraction of the concepts being used.
1.2 Distribution of Models
Some activities like write plan and review plan are obviously useful beyond a certain department or business process, while business plan is a more specific class which will be used in fewer processes. The knowledge what a plan is, is virtually static. It nearly never changes. The meaning of the word business plan and its actual components are changing a bit more often, but less often than the processes a business plan is involved in. The consequence of this observation is to split the models into several smaller models. These sub models may be located physically on different places and even may be maintained by different persons. Each of these models contains a set of objects on a specific layer of abstraction. It may be divided into multiple logical scenarios or contexts.
For some projects it has been useful to invest some manual effort into the graphical layout of those scenarios. Once the concepts have a textual definition, synonyms and eventually graphical symbols, the model may be published for human reference as HTML on the intranet. Even casual users are getting a chance to understand the concepts and terminology just by looking on the contextual information. Using namespaces multiple meanings of a word can be represented and -even more important- explained.
During the actual making of the process model the user has the option to select one or more contexts and ontologies, which are relevant for his current use case. The tool supports him while adding new terms by offering existing terms from the ontology. It also will look up terms in the selected ontology and give access to associated concepts, more general or more specific concepts.
Fig. 2. Types of Models used for BPM
As visualized in figure 2, documents, data models and interviews are the major sources to build ontologies. There are class models for abstract concepts and instance models describing specific objects. Some models will pre-classify the concepts in respect to the applied BPM method. In that sense there are libraries for products, types of organizational units, types of media etc. Even concrete objects like a distinct department or a SAP system may be part of such a library in order to be able to reuse it later on in multiple business processes. For the purpose of business process models the classes will be described with applicable verbs. These models are the foundation of a component library to be used in multiple process modelling projects and applications such as project management based on those processes.
1.3 Semantic Web
In case an object like order is going to be used from an external library in a local model, a copy (proxy, stub..) of that concept will be created. This local object keeps a reference to the external object as shown in figure 3. By using this reference, objects can be replicated similar to the functionality known from Lotus Notes databases. They are being updated on demand in case the referenced objects have been modified. Users may browse the external library in order to extend their local model by related objects from the external model. Objects have a unique name (URN) and a physical address or location which specifies how to retrieve their specification. This may be a file or a server which actually stores the master definition.
The architecture is strongly related to a concept known as "Semantic Web", proposed by the W3C. The main idea is to create a kind of internet made of data additional to the existing web made of text. This is the main reason why we are using the W3C notation OWL  for representing model data. There is an alternative format named ISO Topic Maps which has its primary focus in describing meta information for documents. Semantic Web has its focus in models as elements of knowledge, rather than modelling documents.
We are extending the approach of the Semantic Web, which is mainly about static information models, by process components and workflow descriptions as new elements of knowledge. Related work to our approach has been undertaken in the DAML-S community . They are describing web-services using process models. Both approaches add procedural knowledge to static knowledge. In case of DAML-S the static knowledge is the input / output specification coming from WSDL .
Fig. 3. Types of Models used for BPM
To partition models into independent linked sub-models without having a central coordinating consistency checker is very similar to hyperlinks in HMTL. It makes it easy to reuse knowledge, but has built in the risk of broken links. There is some significant manual effort in maintaining the evolution of an ontology. The major task is to decide which concepts are included in a specific model having a definition agreed by the community. This effort has to be undertaken regardless which modelling tool or strategy is being used. There seems to be no way how this ever will be done by machines.
The main advantage of the proposed method is to make offers to those people building their personal models. We are offering to use objects which are consistent with the corporate terminology, but we do not strictly enforce this consistency. This is reducing modelling efforts because people can reuse existing components. It also tries to avoid time consuming approval processes, which very often are the reason for not using central glossaries.
1.4 Creating Ontologies
The ontology usually covers central relevant terms with their definitions and relations to other terms. Sources for those terms are text, interviews and workshops. There are a couple of tools available to support the development of the ontology. Some of them are databases linked to document management systems. Others are text-mining tools, which help to extract domain specific terms. The ontologies are stored using the Semantic Web format OWL. They are available as a library for use in modelling projects. Especially for the use in process models, verbs and attributes may be included in the ontology.
Fig. 4. Subset of a German E-Government Ontology
Very often external glossaries are used in this situation. A very popular repository to use are business objects from SAP's ASAP toolkit. There are a couple of other ontologies available on the web, some of them even in the Semantic Web format OWL or its predecessor DAML+OIL ,,.
1.5 Task Structure Models Composition of task names
Once having created ontologies and assigned relevant verbs these will be used to define libraries of activities. These libraries contain information about tasks and possible subtasks. Tasks are basically independent from the concrete sequence in a process and describe the list of potential subtasks of a process. They establish the repository of tasks needed to build a concrete process together with the domain expert. The task structure shown in figure 5 gives an impression how such a task structure might look like.
Fig. 5. Task / Subtask structure
If you look at certify product you will notice that check Functionality might be an important process step. In this model there is nothing stated about this subtask being optional or mission critical for the process. There will not be any ordering of the subtasks at all in this library. It is just a list of possible components. Further consistency rules can be specified. You might say that a certain task must be a predecessor of another task. E.g. an order must be confirmed before it is being processed. These rules will enforce a sequence of task in the processes.
1.6 Consistency Checking
SemTalk can validate those rules locally for one model and the set of processes included in the current model. Because the models are saved in a W3C compliant format, the rules (or "axioms") can be checked for multiple models by Semantic Web inference engines such as Cerebra from Network Inference or Ontobroker from Ontoprise GmbH. This technology is used to find non trivial inconsistencies in multiple models.
Let´s assume we have two business processes modelled. One of them describes the order entry and the other one order processing. Let´s further assume that there is a consistency rule stating that only confirmed orders can be processed. Both processes may have been made independently of each other by their respective process manager, but refer to the global object order. The problem is, that the order processing department usually begins working on a prototype after they made a bid. Even if there are no local consistency problems in both of the models, there is a conflict in the union of both models. This is a typical BPM problem that can be detected using Semantic Web inference engines.
Ontology-based process modelling solves some of the most important problems which could be identified analyzing business process models from past projects:
- Modularization of models
- Improved maintainability
- Less learning effort for casual end users
- Sharing terminology with other knowledge intensive technology
- Use of reference objects instead of reducing large monolithic models
Ontology-based process modelling is not the silver bullet in every modelling situation. The examples mentioned in this paper such as localization of plant building and plant maintenance in the pharmaceutical industry or E-Government reference models obviously have a strong character of reference models (see chapter 3). A consulting product like E-Government Quick-Check can be offered with a better quality and for a better price once there is enough pre-defined content available. Even with respect to all local specialities, processes of the local authorities are strongly bound to legislation. The same applies to chemical industry.
The process modelling community is divided into two major groups. There are IT-departments and consultancy firms which are using standard BPM tools. These users usually made a fairly high investment in tools and process modelling education. The other group are the actual owners of the processes coming from various departments. They are mainly using MS PowerPoint or Visio. This group does usually not focus on reusability and company wide consistency. Quite often MS Project is used directly in order to specify a planned task. The problem which arises is that all the knowledge formalized by the second group is more or less lost from the company's or IT departments point of view. Given this problem we are supporting the IT department in offering a solution which covers both interests: company wide consistency and reusability in the "Corporate Semantic Process Web" and the use of MS-Office presentation tools for fast result.
2 Process Modeling Methods
Visio is a popular drawing and flow charting tool. SemTalk extends Visio by the functionality which is needed for business process modelling. It provides support for navigation, consistency and reporting. It bridges the gap between professional BPM experts and casual users, because it is offering support for standard BPM methods within Visio. Modelling methods can be defined graphically within Visio using SemTalk (left side of figure 6). The semantics of a Visio shape is being defined in this meta model. The meta model defines which types of shapes can be connected with other shapes, on which diagram types they appear, which attributes they have etc. This open architecture allows to define new modelling methods in a fast and flexible way.
Fig. 6. MetaModel of a BPM Method
SemTalk comes with a set of predefined BPM methods such as SAP's Event Process Chain (EPC), IMG AG's Promet  and the Communication Structure Analysis (CSA) known from Bonapart . Each of these methods can be logically and graphically customized to match the requirements of customers.
Certain problems require a specific view on a business process in order to visualize a certain aspect of the model. The E-Government models have been described using the CSA notation which emphasises the flow of information in a process rather than the flow of control. In order to visualize specific questions relevant for E-Government such as the responsibility of organisational units or the change of IT-systems, a swim-lane notation for each view on the process may be generated (Figure 7). These visualisations are well suited to discuss the problem together with the involved users. This is a good example how we can use the graphical options of Visio in conjunction with the flexible meta model concept of SemTalk.
Fig. 7. Swim-Lane View of a Process
Beyond the open meta model, the main difference to other modelling tools is the ontology based modelling method which can be applied to any chosen BPM method.
3 Use Case: Project Management
Mission critical goals are being reached in global organizations using a project based structure and project management tools. A similar range of problems as discussed in the paper also applies to project plans, if they were made using traditional project management tools.
The proposed solution is to generate project plans from modelled business processes. It is assumed that those plans will increase the reliability and accuracy of project execution. It will lower the risk to redo process steps which have been recognized as being misleading (minimization of risk). It ensures that those project steps which have proven to be successful will not be omitted (quality assurance). The overall efficiency will be improved by learning from reference projects.
In order to validate this process based approach the pharmaceutical corporation made an internal study to find out how far it will improve project management. The study basically followed the criteria worked out in a recent study of FHG-IAO . Several project managers have been interviewed and a couple of business process modelling tools have been evaluated. The overall result of the evaluation of the interviews was, that using a template based approach will be helpful in order to gain more control and comparability over the project execution schedule. A second result of the investigation was, that there is a major demand in integration capabilities of the tools used.
Looking closer, it became clear, that tools are needed that would be able to store and present complex process structures as reference models. Based on these reference models project plans are generated; project mangers have to be able to customize these reference processes. Therefore the tool has to support distributed modelling. Furthermore there has to be an interface between the modelling tool and the project management tool. The tool has to be flexible enough to customize models or plans in a defined way to assure fulfilment of basic requirements.
Fig. 8. Value Chain “Project Plan”
Object oriented modelling of process elements enables people to develop and maintain complex models of high quality with relatively small effort. A reference model based system can be realized in a rather easy way by using distributed modelling and ontology based modelling mechanisms.
To establish the interface between process modelling and project management a tool has been developed to map processes in the process library and plans in MS Project.
Fig. 9. MS Project Interface
Representation of processes that were to be used as MS Project templates was done with the CSA method (Bonapart). This method matches the meta model of MS Project fairly well, as it has clearly defined semantics based on coloured Petri nets that fit with modelling elements of MS Project
Furthermore this method is a good choice
· if models are to represent the working together of human beings or human beings and machines,
· if processes are complex and very hierarchical,
· if models are to be used on a long term and therefore need more maintenance than others.
MS Project is an example that clearly shows the advantages of an ontology based approach: On one hand maintainability and transparency of processes grow significantly by using a BPM Tool. End users acceptance rises and projects can be installed more quickly. On the other hand using ontologies makes projects comparable concerning the subject. Project templates can be combined in a sensible way, as subjects of projects now are based on a commonly defined semantic system. Reuse of project knowledge and project experiences is possible now. Going a step further and using new features of MS Project´s latest version, integrating MS Sharepoint Portal Server will offer a real project knowledge management system. It will be most efficient using the same semantic system for document classification and process definition.
4 Summary and Future Research
The proposed methodology is based on two key ideas: Composition of task names from classes and verbs and specification of those objects explicitly in reference libraries using the Semantic Web format OWL. This can only be done by establishing an organizational infrastructure to maintain logical separated reference models and a tool which supports replication of models as well as it supports the user while selecting model elements from relevant libraries. This approach has its strength where ever reference models are applicable. The great advantage for the end user who really needs to create process models or project plans as reliable, as fast and as impressive as possible, is, that he still can use MS Visio and nevertheless be consistent with the corporate terminology. Vice versa models created by any department can be integrated meaningfully in the corporate knowledge management system.
The methodology presented in this paper is independent from the notation of business processes being used, but the notation has a significant impact on how these processes can be interpreted by humans and machines. Semantic Web is about machine understandable models as there are information models and process models such as the description of web services. Some of them will be just programs. Others may trigger complex business processes with human involvement. One of the major goals of business process modelling has always been process optimization by simulation. This will include in the future services, published as web services. Process simulation is usually realized by a Petri-Net interpreter. The behaviour of physical and human resources executing tasks is simulated in most systems using simple queuing. Next generation business process simulation, based on the reasoning capabilities of Semantic Web, will implement this in much smarter way by using technologies known from agent systems that understand the information, which is passed on a token.
"The software industry is building an alphabet but hasn't yet invented a common language" Hasso.Plattner SAP AG, 2002 . Using ontologies and W3C recommendations for business process models is a new approach that will lead to open and distributed reference models. Business processes can be easier combined once there is a common semantics for the objects being exchanged. Consistency will be ensured statically using inference engines and dynamically via simulation.
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 .Please refer to the PROMET Method of IMG AG, St. Gallen . The SemTalk implementation of this method can be ontology-based.
 The E-Government Quick-Check solution was developed jointly with Knowlogy Solutions AG and T-Systems AG. It contains some new approaches to measure business processes especially for E-Government. It is based on the ICT (Information - Communication - Transaction) paradigm of Booth-Allen-Hamilton, which can not be explained in detail in this paper.