Table of Contents
1 Introduction Kuo-Ming Chao Nathan Griffiths 1
1.1 Distributed Systems 1
1.2 Software Agents 2
1.3 Service-Oriented Architectures 4
1.4 Modelling Methodologies 5
1.4.1 Agent Modelling Methodologies 6
1.4.2 SOA Modelling Methodologies 7
1.4.3 Agents and Services 8
1.5 Supporting Development Platforms 9
1.6 Agents and SOA Standards 10
1.6.1 Foundation for Intelligent Physical Agents (FIPA) 11
1.6.2 SOA and Web Service Architecture Standards 11
1.7 Overview of Chapters 13
1.8 Conclusion 17
References 21
2 Service Advertisement and Discovery Shanshan Yang Mike Joy 21
2.1 Introduction to Service Advertisement and Discovery 21
2.2 Basic Technologies 24
2.2.1 SOAP 24
2.2.2 WSDL 25
2.2.3 UDDI 25
2.3 Web Service Registry Architectures 26
2.3.1 Centralised Registries 26
2.3.2 Decentralised Registries 27
2.3.3 Hybrid Registries 30
2.4 Data Structures 31
2.5 System Requirements 33
2.6 Advertisement and Discovery Services 34
2.7 Agents in Service Advertisement and Discovery 36
2.7.1 Agents in Service Oriented Computing 36
2.7.2 Development of Agents in Service Advertisement and Discovery 37
2.8 Challenges in Service Advertisement and Discovery 40
2.8.1 System Requirements 41
2.8.2 System Modelling 41
2.9 Summary 41
References 42
3 Multi-Agent Coordination for Service Composition Junzhou Luo Wei Li Bo Liu Xiao Zheng Fang Dong 47
3.1 Introduction 48
3.2 Preliminaries 49
3.2.1 Service Composition 49
3.2.2 QoS Attributes and User Satisfaction Degree of Service 52
3.2.3 Task Graph 53
3.2.4 Service Composition Graph 54
3.2.5 From Task Graph to Services Composition Graph 55
3.2.6 The Fundamentals of the Ant Algorithm 56
3.3 Related Work 57
3.3.1 Framework of Service Composition 57
3.3.2 Service Composition Plan Generation 58
3.3.3 Service Selection and Plan Optimization 58
3.3.4 Multi-Agent Based Service Composition 59
3.4 Architecture of MQSC 60
3.4.1 Portal Agent 60
3.4.2 Decision Agent 61
3.4.3 Search Agent 61
3.4.4 Registry Agent 62
3.4.5 Management Agent 62
3.4.6 Execution Agent 62
3.5 Service Composition Generation 63
3.5.1 Service Search and Composition Plan Generation 63
3.5.2 QoS-Aware Service Selection 64
3.6 Service Composition Deployment and Execution 66
3.6.1 How to Manage the EA to Implement the Composite Plan for the MA 67
3.6.2 The Plan Scheduling Algorithm of the EA 67
3.6.3 An Example for the Scheduling Algorithm of the EA 69
3.7 Case Study 71
3.7.1 Case Scenario Description 71
3.7.2 Multi-Agent System for Service Composition 74
3.7.3 Travel Assistant Service Compositing 75
3.8 Conclusion and Future Work 78
References 79
4 Flexible Workflow Management in Service Oriented Environments Birgit Hofreiter Christian Huemer 81
4.1 Introduction 81
4.2 Orchestration and Choreography 83
4.2.1 Motivation and Definitions 83
4.2.2 Orchestration 84
4.2.3 Local Choreography 86
4.2.4 Global Choreography 88
4.2.5 Approaches to Transform Between Orchestration and Choreography 89
4.3 Workflow and Web Services 90
4.3.3 Web Services Standards for Business Processes 90
4.3.2 Specifying a Business Process by Means of BPEL 90
4.3.3 Analyzing BPEL by Workflow Patterns 97
4.4 The Role of Agents in Service-Based Business Processes 98
4.5 Dynamic Workflows 100
4.5.1 Dynamic Selection of Best Service Providers 100
4.5.2 Changes to the Workflow Schema 103
4.6 Summary and Outlook 107
References 108
5 Semantics for Service-Oriented Architectures Michael Stollberg Dieter Fensel 113
5.1 Introduction 113
5.2 Web Services and SOA 115
5.2.1 Web Services 115
5.2.2 Service-Oriented Architectures 117
5.3 Semantic Web Services 119
5.3.1 Ontologies and the Semantic Web 120
5.3.2 SWS Frameworks 122
5.4 Semantic Techniques for Automating SOA 126
5.4.1 Discovery 127
5.4.2 Selection and Ranking 129
5.4.3 Behavioral Compatibility 130
5.4.4 Composition 130
5.4.5 Mediation 131
5.4.6 Automated Execution 132
5.5 Conclusions and Outlook 132
5.5.1 Summary 133
5.5.2 Future Challenges 134
References 135
6 Dependability in Service-Oriented Computing Arshad Jhumka 141
6.1 Introduction 141
6.2 Service-Oriented Architecture 143
6.2.1 Dependability Issues in Service-Oriented Architectures 146
6.3 Models 147
6.3.1 System Models 147
6.3.2 Fault Models 148
6.4 Dependability Enhancement in a Service Oriented Architecture 152
6.4.1 Fault Prevention 152
6.4.2 Fault Tolerance 153
6.4.3 Fault Removal 154
6.4.4 Fault Forecasting: Fault Injection 154
6.5 Dependability Evaluation 155
6.6 Case Studies 157
6.6.1 A Web-Based Application 157
6.6.2 Service-Oriented Computing in Ubiquitous Systems 159
6.7 Conclusions 159
References 160
7 Consensus Issues for Service Advertisement and Selection Ping Wang Chi-Chun Lo Leon Smalov 161
7.1 Introduction 161
7.1.1 Semantic Confusion 162
7.1.2 Reaching Consensus 164
7.2 Existing Solutions for Web Service Selection 165
7.3 The Proposed QoS-Aware Services Selection Model 170
7.3.1 Basic Definitions and Notations 171
7.3.2 Consistence and Inconsistence Measurements 171
7.3.3 Problem Formulation 174
7.4 Two Numerical Cases 176
7.4.1 Numerical Case I 176
7.4.2 Numerical Case II 179
7.5 Discussion 184
7.6 Conclusion 185
References 185
8 Trust and Reputation Sarah N. Lim Choi Keung Nathan Griffiths 189
8.1 Introduction 189
8.2 Trust and Reputation 190
8.2.1 Trust 190
8.2.2 Reputation 191
8.2.3 The Multiple Approaches to Trust and Reputation Models 191
8.2.4 Review of Trust and Reputation Models 194
8.2.5 Summary of Views of Trust and Reputation Models 210
8.3 Agents and Service-Oriented Computing 211
8.3.1 Peer-to-Peer Architectures 211
8.3.2 Grid Computing 215
8.4 Trust Classes and Ontologies 218
8.4.1 Trust Semantics 219
8.5 Summary 220
References 220
9 QoS-Aware Service Selection James W. J. Xue Stephen A. Jarvis 225
9.1 Introduction 225
9.2 Service Selection Procedure 226
9.3 Case Study-Selection of Switching Service 227
9.3.1 Server Switching in Internet Hosting Centres 227
9.3.2 Server Switching Procedure 229
9.3.3 Modelling Multi-tier Internet Services 229
9.3.4 Model Parameterisation 232
9.3.5 Bottleneck Identification of Multi-tier Architecture 232
9.3.6 Server Switching for Revenue Maximisation 234
9.3.7 Switching Policies 236
9.3.8 Proactive and Reactive Switching 239
9.3.9 Admission Control 240
9.4 Performance Evaluation 240
9.4.1 Experimental Setup 240
9.4.2 Evaluation Results 241
9.5 The Selection of Switching Services 249
9.6 Summary 250
References 250
10 Future Directions Nathan Griffiths Kuo-Ming Chao Simon Miles Sanjay Modgil Nir Oren Michael Luck Kwei-Jay Lin 253
10.1 Introduction 254
10.2 Trust and Reputation 254
10.2.1 Standardisation 255
10.2.2 Technology Integration 256
10.2.3 Further Challenges for Trust and Reputation 257
10.3 Contract-Based Systems 258
10.3.1 Electronic Contracts 259
10.3.2 Conceptual Frameworks for Contract-Based Systems 260
10.3.3 Supporting Architectures for Contract-Based Systems 260
10.3.4 Existing Work and Future Directions 261
10.4 Service Accountability 262
10.4.1 Introduction to Accountability 263
10.4.2 SOA Accountability 263
10.4.3 Accountable Service Computing Model 264
10.4.4 Accountability System Components 267
10.4.5 Related Work 268
10.4.6 Future Direction 269
References 270
Index 273
