The main research question presented in Chapter 1 is:
How can semantic interoperability of process models be improved by using semantic technologies such as ontologies in the process knowledge management applications?
Generally, this question has been answered by an ontology-based semantic anno-tation method, i.e. building the theory of a semantic annoanno-tation framework and a semantic annotation model based on a set of ontologies, and the design and implemen-tation of an ontology-based semantic annoimplemen-tation tool, and as well as the applicability validation in business process knowledge management applications.
Furthermore, we elaborate the answers to more specific sub-questions.
• RQ1. What kind of semantic interoperability problems exist in business process knowledge management?
This question is related to semantic heterogeneity of business process models. We first studied modeling basis of business process management and identified two levels semantic heterogeneity in process models — meta-model level and model level. In general, two cases of semantic discrepancies on both levels can be in-terpreted according to the relationships between sign, referent, and concept in the semiotic triangle: 1) various signs of referents refer to the same concepts;
2) synonymic signs of referents refer to different concepts. The discussion about modeling basis and semantic discrepancies is provided in Chapter 2, Chapter 3 and Chapter 4. We surveyed semantic heterogeneity of a number of process modeling languages by examining modeling constructs corresponding to the busi-ness process modeling perspectives in Chapter 3. Semantics of model contents are dependent on business domains, and only the general semantic discrepancies are considered in this work. The research scope is narrowed down to a study of models in one business domain which is exemplified in the exemplar studies in Chapter 7 and a walkthrough scenario in Chapter 9.
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166 CHAPTER 10. CONCLUSIONS AND FUTURE WORK
• RQ2. What kind of ontologies are required for process knowledge management and how to represent them?
Ontologies can provides a standard and formal representation of a conceptual-ization, which can be used for semantic reconciliation. Through the analysis of semantic discrepancies at both levels, meta-model and model levels, we have de-termined that a process modeling ontology is needed for the meta-model level and a business domain ontology is necessary for the model level. A general process ontology — GPO has been proposed and the concepts and their relationships have been defined in a meta-model of process models in Chapter 4. A business domain is determined by the use cases so that the domain ontology is driven from the SCOR reference models. The ontological representations of SCOR have been exemplified in Chapter 7. Besides, a goal ontology representing the process objectives have been regarded as an additional requirement for managing pro-cess knowledge. The goal ontology is associated with the contextual semantics of process models, and moreover goal specifications can be used in the goal-driven process knowledge management. A general goal ontology representation has been defined in Chapter 5. In order to facilitate associating goals with processes, some concepts in GPO are reused in the goal ontology representation. A specific goal ontology is domain dependent and an example of the specific goal ontology of SCOR domain has been used in exemplar studies in Chapter 7. All the ontolo-gies have been modeled in OWL with Protégé in order to make use of Semantic Web technologies in applications.
• RQ3. What metadata are essential for process model interoperability and how are they defined concerning reference ontologies for reconciliation of the heterogeneous semantics of process models?
In Chapter 4 and Chapter 5, we have presented our semantic annotation frame-work, consisting of profile annotation, meta-model annotation, model annotation and goal annotation. The annotation metadata is also referred as annotation schema in this thesis. A set of metadata including Dublin Core has been catego-rized into the types of administrative, descriptive, preservation, technical and use to describe the profile information of process models in Table 4.1. In the meta-model annotation, different process meta-modeling languages are mapped to GPO to reconcile the different modeling constructs with the common definitions in GPO.
There are three cases of mapping: one-one, many-one and combination-one, which need to be specified in the meta-model annotation schema. GPO is the basis of the semantic annotation framework and it constructs the semantic annotation model for model annotation and goal annotation after the meta-model annota-tion. In the semantic annotation model, process knowledge in original models is represented in a common knowledge representation format. Model annota-tion is to refer model contents to domain ontology concepts. Simple reference is not sufficient for specifying the semantic discrepancies. We refined the ref-erence through semantic relationships (such as synonym, polysemy, hypernym, hyponym, meronym, holonym and instance) which are usually used in ontology specifications, so that the model annotation looks like to build "intermediate on-tologies" between the domain ontology concepts and the local model contents.
10.1. RESEARCH QUESTIONS AND FINDINGS 167 During the process knowledge management, the "intermediate ontologies" can be used to rank and infer the knowledge query results (see Chapter 8). Those se-mantic relationships are defined in the sese-mantic annotation model together with the relationships defined in GPO. The semantic annotation model is the model annotation schema. Such model annotation schema is extended by goal annota-tion metadata achieves, positively_satisfies and negatively_satisfies, which are used to associate goal ontology concept with process model fragments.
The semantic annotation schema is defined in OWL and a semantic annotation model is instantiated when it is generated as a result of meta-model annotation.
• RQ4. How can Semantic Web technology to be incorporated in a tool using the proposed approach?
We have integrated the Protégé Java API into the prototype of our annotation tool — ProSEAT to manipulate the ontologies edited in Protégé (see Chapter 6). With the tool, users can browse the ontologies and select reference concepts from the ontology for the annotation. The tool supports manual mapping be-tween GPO and process modeling languages, automatic generation of an OWL instances of a semantic annotation model for the model and goal annotation, man-ual model annotation and semi-automatic goal annotation. Annotation results are saved in the OWL instance model, which can be read by any OWL supported system. Semantic inference can be made on the annotation results using OWL DL reasoners such as Racer [61], FaCT++ [162], KAON2 [118], Pellet [96].
• RQ5. How can we use the proposed approach to facilitate process knowledge man-agement?
The annotation procedure with the annotation tool in exemplar studies has been elaborated in Chapter 7. Based on the annotation results, a process knowledge management application has been demonstrated in Chapter 9. We have vali-dated the applicability of semantic annotation approach and results. The process knowledge management activities — process knowledge query and process model integration — have been analyzed through checking the satisfactions of a set of identified application requirements. Semantic Web technologies — OWL DL in-ference with SWRL rules has been applied in the applications and evaluations.
The positive evaluation results proved the quality and applicability of the se-mantic annotation approach in the exemplified process knowledge management application.
From the answers to the research questions, we can associate them with the ob-jectives specified in Chapter 1. We therefore conclude: the solutions to RQ1 achieve the objective "to investigate semantic heterogeneity issues in business process model-ing"; the solutions to RQ2 and RQ3 achieve the objective "to explore a comprehensive annotation approach to deal with heterogeneous semantics of process knowledge with referenced ontology"; the solutions to RQ4 achieve the objective "to develop an anno-tation tool to implement the approach by applying Semantic Web technologies"; the solutions to RQ5 achieve the objective "to evaluate quality and use feasibility of the proposed approach and tool in supporting process knowledge management activities".
168 CHAPTER 10. CONCLUSIONS AND FUTURE WORK