1 Context Modeling and Constraints Binding in Web Service Business Process Kosala Yapa Bandara, MingXue Wang, Claus Pahl Dublin City University Summarized and presented by Hong-Linh Truong Distributed Systems Group, Vienna University of Technology CASTA'09, 24 August 2009, Amsterdam,The Netherlands

2 Outline Objective and Assumption Approach Context Ontology Model for Web Services Context Constraints Discussion

3 Objective and Assumption Support the development of context-determined dynamic Web services applications Application operations are influenced by context Focus on business processes of Web services Why it is important? Dynamic business process goals are dependent on context and constrains (some established based on context?) A context ontology (terms and concepts) enables contraints modeling/reasoning and integration The papers Brief a context ontology and contraints based on the ontology

4 Ontology-based Context Framework for Service Process Focus on execution, dynamic composition and monitoring of processes Context ontology for capturing context aspects which are relevant for dynamic service process composition and monitoring Approach Constraint determination Constraint modeling Instrumentation

5 The Context Ontology Model Functional context Syntax (Input/Output), Effect (pre/post condition), Protocol Context (context on communication and data flows) QoS Runtime attributes (performance/reliability) financial/business attributes (cost, reputation, regulatory), security attributes (integrity, authentication, etc.), trust attributes Domain Context Domain specific (semantic, linguistic, measures and standards) Platform Context Device, connectivity

6 The Application of the Context Ontology: Context Constraints Constraints and instrumentation probes are generated from service profiles Utilize service profiles Constraints generated from the context ontology Instrument, monitor and validate constraints based on different context categories

7 Some Thoughts for Discussion Service Context Ontology versus Process Context Ontology What about the reusability of context models (e.g. workflow performance ontology, QoS for WS, etc., service licensing)? Relevant to process composition How the context ontology and SLA (in service profile) are used to generate constraints? How SLAs are specified? How it is related to MDD (Model-Driven Development) approaches, such as ContextUML and its applications Checking constraints at design time: There are syntax matching, QoS determination, service licensing compatibilty, etc.

8 Some Thoughts for Discussion Constraint monitoring It seems it can handle all kinds of constraints? Generic binding to existing constraint services Which constraint services could be? How generic constraint services could be? How is the relationship of the work with workflow performance analysis, workflow mining, QoS ontology What would be the binding to existing performance/SLA monitoring systems? Binding to monitoring systems: can it be done automatic?