NATIONAL AND KAPODISTRIAN UNIVERSITY OF ATHENS DEPARTMENT OF INFORMATICS AND TELECOMUNICATIONS PROGRAM OF POSTGRADUATE STUDIES DIPLOMA THESIS Sharing of Semantically Enhanced Information for the Adaptive Execution of Business Processes Pigi D. Kouki Supervisor: Aphrodite Tsalgatidou, Assistant Professor NKUA Technical Support: Georgios Athanasopoulos, PhD Candidate NKUA ATHENS MAY 2011 DIPLOMA THESIS Sharing of Semantically Enhanced Information for the Adaptive Execution of Business Processes Pigi D. Kouki Registration Number: Μ 984 SUPERVISOR: Aphrodite Tsalgatidou, Assistant Professor NKUA TECHNICAL SUPPORT: Georgios Athanasopoulos, PhD Candidate NKUA MAY 2011 ABSTRACT Motivated from the Context Aware Computing, and more particularly from the Data-Driven Process Adaptation approach, we propose the Semantic Context Space (SCS) Engine which aims to facilitate the provision of adaptable business processes. The SCS Engine provides a space which stores semantically annotated data and it is open to other processes, systems, and external sources for information exchange. The specified implementation is inspired from the Semantic TupleSpace and uses the JavaSpace Service of the Jini Framework (changed to Apache River lately) as an underlying basis. The SCS Engine supplies an interface where a client can execute the following operations: (i) write: which inserts in the space available information along with its respective meta-information, (ii) read: which retrieves from the space information which meets specific meta-information constrains, and (iii) take: which retrieves and simultaneously deletes from the space information which meets specific meta-information constrains. In terms of this thesis the available types of meta-information are based on ontologies described in RDFS or WSML. The applicability of the SCS Engine implementation in the context of data-driven process adaptation has been ensured by an experimental evaluation of the provided operations. Ultimately, we refer to open issues which could be addressed to enrich the proposed Engine with additional features. SUBJECT AREA: Semantic TupleSpace KEYWORDS: Service Oriented Computing, Context Aware Computing, Service Adaptation, Distributed Computing TABLE OF CONTENTS PREFACE ............................................................................................................................ 8 CHAPTER 1 INTRODUCTION ............................................................................................. 9 1.1 Motivation and Objectives of the thesis ....................................................................... 9 1.1.1 Envision Project ................................................................................................... 10 1.2 High level goals and needs .......................................................................................... 10 1.3 Structure of the thesis ................................................................................................ 11 CHAPTER 2 TECHNOLOGICAL BACKROUND ..................................................................... 13 2.1 TupleSpace Computing ............................................................................................... 13 2.1.1 Linda Coordination Language .............................................................................. 13 2.1.2 Significant Approaches in Semantically enhanced TupleSpace Technology ....... 14 2.1.2.1 sTuples ........................................................................................................... 14 2.1.2.2 Semantic Web Spaces ................................................................................... 15 2.1.2.3 Triple Space Computing (TSC) ....................................................................... 18 2.1.2.4 Conceptual Spaces (CSpaces) ........................................................................ 21 2.1.3 WSMX .................................................................................................................. 24 2.1.3.1 Main Components ......................................................................................... 25 2.1.3.2 Architecture ................................................................................................... 26 2.2 JavaSpaces ................................................................................................................... 27 2.2.1 Architecture ......................................................................................................... 27 2.2.2 JavaSpaces Interface – Supported Operations .................................................... 29 2.2.3 Application Model ............................................................................................... 30 2.3 Comparative Study ...................................................................................................... 31 CHAPTER 3 SEMANTIC CONTEXT SPACE ENGINE ............................................................. 36 3.1 Design Decisions on the SCS Engine ........................................................................... 36 3.1.1 Implementation Basis .......................................................................................... 36 3.1.2 Extensions ............................................................................................................ 37 3.1.3 Information Model .............................................................................................. 38 3.2 Semantic Context Space Architecture ........................................................................ 39 3.2.1 Data Manager ...................................................................................................... 40 3.2.2 Query Processor .................................................................................................. 40 3.2.3 Meta-Information based Interface ...................................................................... 41 3.3 SCS Engine Interface ................................................................................................... 41 3.3.1 Engine Initialization ............................................................................................. 42 3.3.1.1 Initialization Process Description .................................................................. 43 3.3.2 Write Algorithm ................................................................................................... 52 3.3.3 Read Algorithm .................................................................................................... 53 3.3.4 Take Algorithm .................................................................................................... 58 CHAPTER 4 EVALUATION ................................................................................................. 59 4.1 SCS Engine Case Study ................................................................................................ 59 4.2 Performance of the write operation ........................................................................... 59 4.2.1 Expected Results .................................................................................................. 60 4.2.2 Measurement Results .......................................................................................... 60 4.2.3 Comparative study between SCSEngine and JavaSpaces .................................... 63 4.3 Performance of the read operation ............................................................................ 64 4.3.1 Expected Results .................................................................................................. 65 4.3.2 Measurement Results .......................................................................................... 66 4.3.3 Comparative study between SCSEngine and JavaSpaces .................................... 69 4.4 Performance of the take operation ............................................................................ 70 4.4.1 Expected Results .................................................................................................. 70 4.4.2 Measurement Results .......................................................................................... 71 4.4.3 Comparative study between SCSEngine and JavaSpaces .................................... 73 CHAPTER 5 CONCLUSIONS AND OUTLOOK ....................................................................... 74 5.1 Summary ..................................................................................................................... 74 5.2 SCS role in terms of Envision Project .......................................................................... 75 5.2.1 Supported Interfaces in terms of Envision Project .............................................. 75 5.3 Open Issues and Research Challenges ........................................................................ 76 ABBREVIATIONS .............................................................................................................. 78 APPENDIX 1 ..................................................................................................................... 80 Jini Framework – Apache River ............................................................................................ 80 APPENDIX 2 ..................................................................................................................... 84 APPENDIX 3 ..................................................................................................................... 86 REFERENCES ...................................................................................................................