In recent years, there has been a growing debate, particularly in the UK and Europe, over the merits of using discrete-event simulation (DES) and system dynamics (SD); there are now instances where both methodologies were employed on the same problem. This book details each method, comparing each in terms of both theory and their application to various problem situations. It also provides a seamless treatment of various topics--theory, philosophy, detailed mechanics, practical implementation--providing a systematic treatment of the methodologies of DES and SD, which previously have been treated separately.        

Table of Contents:
Preface xv List of contributors xvii 1 Introduction 1 Sally Brailsford, Leonid Churilov and Brian Dangerfield 1.1 How this book came about 1 1.2 The editors 2 1.3 Navigating the book 3 References 9 2 Discrete-event simulation: A primer 10 Stewart Robinson 2.1 Introduction 10 2.2 An example of a discrete-event simulation: Modelling a hospital theatres process 11 2.3 The technical perspective: How DES works 12 2.3.1 Time handling in DES 14 2.3.2 Random sampling in DES 15 2.4 The philosophical perspective: The DES worldview 21 2.5 Software for DES 23 2.6 Conclusion 24 References 24 3 Systems thinking and system dynamics: A primer 26 Brian Dangerfield 3.1 Introduction 26 3.2 Systems thinking 28 3.2.1 ‘Behaviour over time’ graphs 28 3.2.2 Archetypes 29 3.2.3 Principles of influence (or causal loop) diagrams 30 3.2.4 From diagrams to behaviour 32 3.3 System dynamics 34 3.3.1 Principles of stock–flow diagramming 34 3.3.2 Model purpose and model conceptualisation 35 3.3.3 Adding auxiliaries, parameters and information links to the spinal stock–flow structure 36 3.3.4 Equation writing and dimensional checking 37 3.4 Some further important issues in SD modelling 40 3.4.1 Use of soft variables 40 3.4.2 Co-flows 42 3.4.3 Delays and smoothing functions 43 3.4.4 Model validation 46 3.4.5 Optimisation of SD models 48 3.4.6 The role of data in SD models 49 3.5 Further reading 49 References 50 4 Combining problem structuring methods with simulation: The philosophical and practical challenges 52 Kathy Kotiadis and John Mingers 4.1 Introduction 52 4.2 What are problem structuring methods? 53 4.3 Multiparadigm multimethodology in management science 54 4.3.1 Paradigm incommensurability 55 4.3.2 Cultural difficulties 57 4.3.3 Cognitive difficulties 58 4.3.4 Practical problems 59 4.4 Relevant projects and case studies 60 4.5 The case study: Evaluating intermediate care 62 4.5.1 The problem situation 62 4.5.2 Soft systems methodology 64 4.5.3 Discrete-event simulation modelling 66 4.5.4 Multimethodology 67 4.6 Discussion 68 4.6.1 The multiparadigm multimethodology position and strategy 68 4.6.2 The cultural difficulties 70 4.6.3 The cognitive difficulties 70 4.7 Conclusions 72 Acknowledgements 72 References 72 5 Philosophical positioning of discrete-event simulation and system dynamics as management science tools for process systems: A critical realist perspective 76 Kristian Rotaru, Leonid Churilov and Andrew Flitman 5.1 Introduction 76 5.2 Ontological and epistemological assumptions of CR 80 5.2.1 The stratified CR ontology 80 5.2.2 The abductive mode of reasoning 81 5.3 Process system modelling with SD and DES through the prism of CR scientific positioning 82 5.3.1 Lifecycle perspective on SD and DES methods 84 5.4 Process system modelling with SD and DES: Trends in and implications for MS 90 5.5 Summary and conclusions 97 References 99 6 Theoretical comparison of discrete-event simulation and system dynamics 105 Sally Brailsford 6.1 Introduction 105 6.2 System dynamics 106 6.3 Discrete-event simulation 108 6.4 Summary: The basic differences 110 6.5 Example: Modelling emergency care in Nottingham 112 6.5.1 Background 112 6.5.2 The ECOD project 113 6.5.3 Choice of modelling approach 114 6.5.4 Quantitative phase 114 6.5.5 Model validation 116 6.5.6 Scenario testing and model results 116 6.5.7 The ED model 118 6.5.8 Discussion 119 6.6 The $64 000 question: Which to choose? 120 6.7 Conclusion 123 References 123 7 Models as interfaces 125 Steffen Bayer, Tim Bolt, Sally Brailsford and Maria Kapsali 7.1 Introduction: Models at the interfaces or models as interfaces 125 7.2 The social roles of simulation 126 7.3 The modelling process 129 7.4 The modelling approach 131 7.5 Two case studies of modelling projects 134 7.6 Summary and conclusions 137 References 138 8 An empirical study comparing model development in discrete-event simulation and system dynamics 140 Antuela Tako and Stewart Robinson 8.1 Introduction 140 8.2 Existing work comparing DES and SD modelling 142 8.2.1 DES and SD model development process 143 8.2.2 Summary 146 8.3 The study 146 8.3.1 The case study 146 8.3.2 Verbal protocol analysis 147 8.3.3 The VPA sessions 149 8.3.4 The subjects 149 8.3.5 The coding process 150 8.4 Study results 151 8.4.1 Attention paid to modelling topics 152 8.4.2 The sequence of modelling stages 154 8.4.3 Pattern of iterations among topics 155 8.5 Observations from the DES and SD expert modellers’ behaviour 158 8.6 Conclusions 160 Acknowledgements 162 References 162 9 Explaining puzzling dynamics: A comparison of system dynamics and discrete-event simulation 165 John Morecroft and Stewart Robinson 9.1 Introduction 165 9.2 Existing comparisons of SD and DES 166 9.3 Research focus 169 9.4 Erratic fisheries – chance, destiny and limited foresight 170 9.5 Structure and behaviour in fisheries: A comparison of SD and DES models 173 9.5.1 Alternative models of a natural fishery 174 9.5.2 Alternative models of a simple harvested fishery 178 9.5.3 Alternative models of a harvested fishery with endogenous ship purchasing 184 9.6 Summary of findings 192 9.7 Limitations of the study 193 9.8 SD or DES? 194 Acknowledgements 196 References 196 10 DES view on simulation modelling: SIMUL8 199 Mark Elder 10.1 Introduction 199 10.2 How software fits into the project 200 10.3 Building a DES 202 10.4 Getting the right results from a DES 208 10.4.1 Verification and validation 210 10.4.2 Replications 211 10.5 What happens after the results? 212 10.6 What else does DES software do and why? 212 10.7 What next for DES software? 213 References 214 11 Vensim and the development of system dynamics 215 Lee Jones 11.1 Introduction 215 11.2 Coping with complexity: The need for system dynamics 216 11.3 Complexity arms race 219 11.4 The move to user-led innovation 221 11.5 Software support 222 11.5.1 Apples and oranges (basic model testing) 223 11.5.2 Confidence 224 11.5.3 Helping the practitioner do more 237 11.6 The future for SD software 245 11.6.1 Innovation 245 11.6.2 Communication 245 References 247 12 Multi-method modeling: AnyLogic 248 Andrei Borshchev 12.1 Architectures 249 12.1.1 The choice of model architecture and methods 251 12.2 Technical aspect of combining modeling methods 252 12.2.1 System dynamics ® discrete elements 252 12.2.2 Discrete elements ® system dynamics 253 12.2.3 Agent based « discrete event 255 12.3 Example: Consumer market and supply chain 257 12.3.1 The supply chain model 257 12.3.2 The market model 258 12.3.3 Linking the DE and the SD parts 259 12.3.4 The inventory policy 260 12.4 Example: Epidemic and clinic 262 12.4.1 The epidemic model 262 12.4.2 The clinic model and the integration of methods 264 12.5 Example: Product portfolio and investment policy 267 12.5.1 Assumptions 268 12.5.2 The model architecture 270 12.5.3 The agent product and agent population portfolio 271 12.5.4 The investment policy 274 12.5.5 Closing the loop and implementing launch of new products 275 12.5.6 Completing the investment policy 277 12.6 Discussion 278 References 279 13 Multiscale modelling for public health management: A practical guide 280 Rosemarie Sadsad and Geoff McDonnell 13.1 Introduction 280 13.2 Background 281 13.3 Multilevel system theories and methodologies 281 13.4 Multiscale simulation modelling and management 283 13.5 Discussion 289 13.6 Conclusion 290 References 290 14 Hybrid modelling case studies 295 Rosemarie Sadsad, Geoff McDonnell, Joe Viana, Shivam M. Desai, Paul Harper and Sally Brailsford 14.1 Introduction 295 14.2 A multilevel model of MRSA endemicity and its control in hospitals 296 14.2.1 Introduction 296 14.2.2 Method 296 14.2.3 Results 297 14.2.4 Conclusion 302 14.3 Chlamydia composite model 302 14.3.1 Introduction 302 14.3.2 Chlamydia 302 14.3.3 DES model of a GUM department 303 14.3.4 SD model of chlamydia 304 14.3.5 Why combine the models 304 14.3.6 How the models were combined 305 14.3.7 Experiments with the composite model 305 14.3.8 Conclusions 307 14.4 A hybrid model for social care services operations 308 14.4.1 Introduction 308 14.4.2 Population model 308 14.4.3 Model construction 309 14.4.4 Contact centre model 310 14.4.5 Hybrid model 311 14.4.6 Conclusions and lessons learnt 313 References 316 15 The ways forward: A personal view of system dynamics and discrete-event simulation 318 Michael Pidd 15.1 Genesis 318 15.2 Computer simulation in management science 319 15.3 The effect of developments in computing 320 15.4 The importance of process 324 15.5 My own comparison of the simulation approaches 324 15.5.1 Time handling 324 15.5.2 Stochastic and deterministic elements 326 15.5.3 Discrete entities versus continuous variables 327 15.6 Linking system dynamics and discrete-event simulation 328 15.7 The importance of intended model use 329 15.7.1 Decision automation 330 15.7.2 Routine decision support 331 15.7.3 System investigation and improvement 331 15.7.4 Providing insights for debate 332 15.8 The future? 333 15.8.1 Use of both methods will continue to grow 333 15.8.2 Developments in computing will continue to have an effect 334 15.8.3 Process really matters 335 References 335 Index 337