CAFCR: A Multi-view Method for Embedded Systems Architecting; Balancing Genericity and Specificity trecon = tfilter(nraw-x ,nraw-y) + t ) + nraw-x * ( tfft(nraw-y)+ col-overhead ny * ( tfft(nraw-x) + trow-overhead ) + tcorrections (nx ,ny) + tcontrol-overhead Gerrit Muller ii This page will not be present in the final thesis version: 2.9 status: concept date: August 21, 2020 iii CAFCR: A Multi-view Method for Embedded Systems Architecting; Balancing Genericity and Specificity Proefschrift ter verkrijging van de graad van doctor aan de Technische Universiteit Delft, op gezag van de Rector Magnificus prof.dr.ir. J.T. Fokkema, voorzitter van het College voor Promoties, in het openbaar te verdedigen op maandag 7 juni 2004 om 13:00 uur door Gerrit Jan MULLER doctorandus in de natuurkunde geboren te Amsterdam iv Dit proefschrift is goedgekeurd door de promotor: Prof.dr W.G. Vree Samenstelling promotiecommissie: Rector Magnificus voorzitter Prof.dr. W.G. Vree Technische Universiteit Delft, promotor Prof.dr. M. Rem Technische Universiteit Eindhoven Prof.dr.ir. P.A. Kroes Technische Universiteit Delft Prof.dr.ir. H.J. Sips Technische Universiteit Delft Prof.dr. R. Wagenaar Technische Universiteit Delft Prof.dr.ing. D.K. Hammer Technische Universiteit Eindhoven Prof.dr. P.H. Hartel Universiteit Twente Prof.dr. M. Rem heeft als begeleider in belangrijke mate aan de totstandkoming van het proefschrift bijgedragen. ISBN 90-5639-120-2 Keywords: Systems Architecture, System design, Systems Engineering These investigations were supported by Philips Research Laboratories, and the Embedded Systems Institute, both in Eindhoven. Cover Photograph: René Stout http://www.rwstout.com/ Copyright c 2004 by G.J. Muller. This thesis is written as part of the Gaudí project. Further distribution is allowed as long as the thesis remains complete and unchanged. Use of figures is allowed as long as a reference to the source is present. Note that the copyright of photographs resides at the original copyright owners. Preface The industrial world and the academic world have drifted far apart in the imma- ture discipline of systems architecting. The challenge in writing this thesis was to capture the industrial pragmatic experience in a way that is acceptable for the aca- demic community. Moreover, the Embedded Systems Institute has the ambition to mature and extend this discipline. This thesis is a first step in bridging the gap between industry and academics. The personal motivation for writing this thesis is best explained by looking back at my career. I have been active in the hectic product creation environment for about twenty years. More than 17 years I was responsible for several archi- tectures of medical systems. The drawing on the cover has been made in this period to visualize the system designer as a monster with twenty heads, and hence twenty viewpoints. For more than two years I have been heading the Systems En- gineering department at ASML. This period at ASML was very instructive and refreshing. I very much liked the opportunity to educate and coach future as well as senior system engineers in this young discipline. After these twenty years of industrial pressure I joined Philips Research, with as my personal goal to mature the discipline and to make it more accessible and transferable. The Gaudí site www.gaudisite.nl/ shows the ongoing results of this effort. The step from Philips Research to the Embedded Systems Institute1 creates the opportunity to link this experience based work to the academic world. One of the peculiarities of the academic world is that only people with a doc- tor’s title seem to be taken seriously. In the process of writing this thesis I have hit many more aspects of the scientific culture, such as the need to cite others for every statement being made, an extremely redundant writing style, the preference for text over figures, and a focus on the argumentation rather than on the clar- ity or didactic value. Going through this learning experience is very valuable in 1 The Embedded Systems Institute is founded by Philips, ASML, Océ, TNO and the universities of Delft, Eindhoven and Twente v vi PREFACE the interaction with the academic world. I gained a better understanding of the obsession for publication, peer review, and the noise induced by all citations and repetitions in scientific publications. Understanding the motivation and the behav- ior of the academic partners is a prerequisite to bridge the gap between industry and academics. My thinking processes make use of visualizations: diagrams, structures, mod- els, et cetera. This thesis contains over 150 figures. The advantage of figures is that they show the overview and the parts at the same time, whereas text is linear: only after reading the entire text the overview might become clear. Lots of energy has been spent to complement all visualizations with readable text. The broad and multi-disciplinary scope of systems architecting can easily re- sult in generic statements. I have attempted to cope with this danger of over- generalization by providing a very specific case study. This struggle with the balance between genericity and specificity is the daily world of every systems ar- chitect. This struggle repeated itself when writing this thesis. The academic value is in the extraction of more generally applicable knowledge. But the route towards this knowledge meanders through many highly specific details. If both academic people as well as industrial people enjoy reading this thesis then one of my goals has been achieved. So, enjoy reading! Contents Preface v Introduction xi I Introduction to CAFCR and Threads of Reasoning 1 1 What is Systems Architecting in an Industrial Context? 3 1.1 Introduction . 3 1.2 Description of the Business Context . 5 1.3 Internal Stakeholders . 5 1.4 Acknowledgements . 6 2 Overview of CAFCR and Threads of Reasoning 7 2.1 Introduction . 7 2.2 Architecting Method Overview . 7 2.3 The CAFCR Model . 8 3 Introduction to Medical Imaging Case Study 13 3.1 Market and Application . 13 3.2 Technology . 15 4 Positioning the CAFCR Method in the World 19 4.1 Introduction . 19 4.2 Related Work . 19 4.3 What is the Unique Contribution of this Work? . 22 4.4 IEEE 1471 . 24 vii viii CONTENTS 5 Research in Systems Architecting 27 5.1 Introduction . 27 5.2 Technology Management Cycle . 28 5.3 Challenges to do Research in a Scientific Way . 29 5.4 Architecting Research Method . 33 5.5 Distance between Industrial Practice and Scientific Research . 34 5.6 Research Environment . 35 6 Research Question and Hypothesis 37 6.1 Introduction . 37 6.2 Research Question . 37 6.3 Hypothesis . 39 6.4 Criteria . 41 6.5 Summary . 42 II Theory of CAFCR and Threads of Reasoning 43 7 Basic Methods 45 7.1 Introduction . 45 7.2 Viewpoint Hopping . 46 7.3 Decomposition and Integration . 49 7.4 Quantification . 49 7.5 Coping with Uncertainty . 51 7.6 Modeling . 52 7.7 WWHWWW . 53 7.8 Decision Making Approach in Specification and Design . 54 8 Submethods in the CAF Views 59 8.1 Introduction . 59 8.2 Key Drivers . 59 8.3 Customer Business Positioning . 62 8.4 Modeling in the Customer World . 64 8.5 Use Cases . 66 8.6 System Specification . 67 8.7 Overview of the Submethods in the CAF views . 74 CONTENTS ix 9 Submethods in the CR Views 75 9.1 Introduction . 75 9.2 Decomposition . 75 9.3 Quality Design Submethods . 82 9.4 Project Management Support . 89 9.5 Overview of the Submethods in the CR views . 92 10 Qualities as Integrating Needles 93 10.1 Introduction . 93 10.2 Security as Example of a Quality Needle . 94 10.3 Qualities Checklist . 96 10.4 Summary . 101 11 Story Telling 103 11.1 Introduction . 103 11.2 How to Create a Story? . 104 11.3 How to Use a Story? . 105 11.4 Criteria . 105 11.5 Summary . 107 12 Threads of Reasoning 109 12.1 Introduction . 109 12.2 Overview of Reasoning Approach . 109 12.3 Reasoning . 114 12.4 Outline of the complete method . 116 12.5 Summary . 117 III Medical Imaging Case Description 119 13 Medical Imaging in Chronological Order 121 13.1 Project Context . 121 13.2 Introduction . 122 13.3 Development of Easyvision RF . 122 13.4 Performance Problem . 124 13.5 Safety . 127 13.6 Summary . 129 x CONTENTS 14 Medical Imaging Workstation: CAF Views 131 14.1 Introduction . 131 14.2 Radiology Context . 131 14.3 Typical Case . 138 14.4 Key Driver Graph . 139 14.5 Functionality . 144 14.6 Interoperability via Information Model . 145 14.7 Conclusion . 146 15 Medical Imaging Workstation: CR Views 149 15.1 Introduction . 149 15.2 Image Quality and Presentation Pipeline . 149 15.3 Software Specific Views . 152 15.4 Memory Management . 154 15.5 CPU Usage . 160 15.6 Measurement Tools . 161 15.7 Conclusion . 165 16 Story Telling in Medical Imaging 167 16.1 Introduction . 167 16.2 The Sales Story . 168 16.3 The Radiologist at Work . 169 16.4 Towards Design . 170 16.5 Conclusion . 172 17 Threads of Reasoning in the Medical Imaging Case 173 17.1 Introduction . 173 17.2 Example Thread . 173 17.3 Exploration of Problems and Solutions . 175 17.4 Conclusion . 183 IV Evaluation, Discussion and Conclusions 185 18 Evaluation of the Architecting Method 187 18.1 Introduction . 187 18.2 Design Evaluation . ..