Distributed Applications and Interoperable Systems : 19th IFIP WG 6.1 International Conference, DAIS 2019 : held as part of the 14th International Federated Conference on Distributed Computing Techniques, DisCoTec 2019, Kongens Lyngby, Denmark, June 17-21

This book constitutes the proceedings of the 19th IFIP International Conference on Distributed Applications and Interoperable Systems, DAIS 2019, held in Kongens Lyngby, Denmark, in June 2019, as part of the 14th International Federated Conference on Distributed Computing Techniques, DisCoTec 2019. The 9 full papers presented together with 2 short papers were carefully reviewed and selected from 28 submissions. The papers addressed challenges in multiple application areas, such as the Internet-of-Things, cloud and edge computing, and mobile systems. Some papers focused on middleware for managing concurrency and consistency in distributed systems, including data replication and transactions. Foreword 6 Preface 8 Organization 9 DisCoTec Keynotes 11 Versatile Quantitative Modelling: Verification, Synthesis and Data Inference for Cyber-Physical Systems 12 ALGORAND – The Distributed Ledger for the Borderless Economy 13 Making Sense of Fast Big Data (DAIS Keynote) 14 Contents 15 Syncpal: A Simple and Iterative Reconciliation Algorithm for File Synchronizers 16 1 Introduction 16 2 Background 18 2.1 File Synchronizers 18 2.2 File System Model 18 2.3 State-Based Update Detection 20 3 Approach 21 3.1 Phase 1: Preparation 21 3.2 Phase 2: Execution 24 4 Application 25 4.1 Step 1: File System Model Formalization 25 4.2 Step 2: Conflict Detection 26 4.3 Step 3: Resolving conflicts 27 4.4 Step 4: Analysis of Operation Order Dependencies 29 5 Evaluation 31 6 Conclusions 31 References 32 Check-Wait-Pounce: Increasing Transactional Data Structure Throughput by Delaying Transactions 34 1 Introduction 34 2 Related Work 37 2.1 Transactional Data Structure Methodologies 37 2.2 Reordering Transactions 38 3 Check-Wait-Pounce 38 3.1 Algorithm Overview 38 3.2 Algorithm Details 39 4 Correctness 42 4.1 Rules 43 4.2 Strict Serializability and Recovery 43 5 Evaluation 45 5.1 Experimental Setup 45 5.2 Linked List 47 5.3 Skip List 47 5.4 Transaction Size 48 5.5 Check-Wait-Pounce Parameters 48 6 Conclusion 48 References 49 Putting Order in Strong Eventual Consistency 51 1 Introduction 51 2 Strong Eventually Consistent Replicated Objects 52 2.1 SECRO Data Type 53 2.2 State Validators 54 3 SECRO's Replication Protocol 56 3.1 Algorithm 57 4 Evaluation 60 4.1 Methodology 60 4.2 Memory Usage 61 4.3 Execution Time 62 4.4 Throughput 63 5 Related Work 64 6 Conclusion 65 A Proof: Operations Cannot Break the Transitive Closure of Concurrent Operations 66 B The Effect of Commit on the Execution Time 67 C Detailed Execution Time 68 References 70 Composable Actor Behaviour 72 1 Introduction 72 2 Code Reuse in Actor-Based Languages 73 2.1 Inheritance 74 2.2 Trait Composition 74 2.3 Function Composition 74 2.4 Communicating Event-Loops 75 2.5 Problem Statement 76 3 Delegation-Based Actor Composition in Stella 76 3.1 Motivating Example 76 3.2 The Base Stella Language 77 3.3 Delegation-Based Behaviour Composition in Stella 79 4 Operational Semantics of Stella 80 4.1 Syntax 80 4.2 Semantic Entities 81 4.3 Notation 82 4.4 Static Semantics 82 4.5 Dynamic Semantics 84 5 Conclusion 86 References 87 Gossip Learning as a Decentralized Alternative to Federated Learning 89 1 Introduction 89 2 Background 90 2.1 Federated Learning 91 2.2 Gossip Learning 92 3 Algorithms 93 4 Experiments 95 4.1 Datasets 95 4.2 System Model 96 4.3 Smartphone Traces 97 4.4 Hyperparameters and Algorithms 98 4.5 Results 98 5 Conclusions 103 References 104 Using Trusted Execution Environments for Secure Stream Processing of Medical Data 106 1 Introduction 106 2 Background 108 2.1 Technical Background 108 2.2 Heart Rate Variability Analysis 110 3 Architecture 111 3.1 Server-Side 111 3.2 Clients 112 3.3 Threat Model 112 3.4 Known Vulnerabilities 112 4 Implementation 112 4.1 Server-Side 113 4.2 Clients 113 4.3 Deployment 113 5 Evaluation 114 5.1 Settings 114 5.2 Experiment Configurations 114 5.3 Results 116 6 Related Work 119 7 Future Work 120 8 Conclusion 120 References 120 Stunner: A Smart Phone Trace for Developing Decentralized Edge Systems 123 1 Introduction 123 2 Data Collection Methodology 125 3 Some Measurement Results 126 4 Conclusion 129 References 129 FOUGERE: User-Centric Location Privacy in Mobile Crowdsourcing Apps 131 1 Introduction 131 2 Related Work 132 3 Privacy Threats in Mobile Crowdsourcing Systems 134 4 FOURGERE: Empowering Workers with LPPMs 136 5 Implementation Details on Android 138 6 Evaluations of FOUGERE 139 6.1 Evaluation Protocol 139 6.2 Empirical Evaluation 141 7 Threats to Validity 144 8 Conclusion 145 References 146 On the Performance of ARM TrustZone 148 1 Introduction 148 2 Background 150 2.1 TRUSTZONE in a Nutshell 151 2.2 The OP-TEE Trusted OS 153 3 Methodology 153 4 Evaluation 156 5 Lessons Learned 163 6 Conclusion 164 References 164 CapBAC in Hyperledger Sawtooth 167 1 Introduction 167 2 Background 168 2.1 Blockchain 168 2.2 IoT and ACMs 170 3 CapBAC and Blockchains 171 3.1 CapBAC 171 3.2 Blockchains with CapBAC: Characteristics 172 4 Implementation 174 4.1 A New Transaction Family for CapBAC 176 4.2 Testing Environment 178 5 Related Work 180 6 Conclusion and Future Work 182 References 183 Developing Secure Services for IoT with OP-TEE: A First Look at Performance and Usability 185 1 Introduction 185 2 Background 187 2.1 TrustZone in a Nutshell 187 2.2 The GlobalPlatform Specifications for TEEs 187 2.3 The OP-TEE Framework 188 3 Usability 188 4 Performance Evaluation 190 4.1 Setup 190 4.2 Shared Memory 190 4.3 Secure Storage 191 5 Concluding Remarks 192 References 192 Author Index 194 Front Matter ....Pages i-xvii Syncpal: A Simple and Iterative Reconciliation Algorithm for File Synchronizers (Marius Shekow)....Pages 1-18 Check-Wait-Pounce: Increasing Transactional Data Structure Throughput by Delaying Transactions (Lance Lebanoff, Christina Peterson, Damian Dechev)....Pages 19-35 Putting Order in Strong Eventual Consistency (Kevin De Porre, Florian Myter, Christophe De Troyer, Christophe Scholliers, Wolfgang De Meuter, Elisa Gonzalez Boix)....Pages 36-56 Composable Actor Behaviour (Sam Van den Vonder, Joeri De Koster, Wolfgang De Meuter)....Pages 57-73 Gossip Learning as a Decentralized Alternative to Federated Learning (István Hegedűs, Gábor Danner, Márk Jelasity)....Pages 74-90 Using Trusted Execution Environments for Secure Stream Processing of Medical Data (Carlos Segarra, Ricard Delgado-Gonzalo, Mathieu Lemay, Pierre-Louis Aublin, Peter Pietzuch, Valerio Schiavoni)....Pages 91-107 Stunner: A Smart Phone Trace for Developing Decentralized Edge Systems (Zoltán Szabó, Krisztián Téglás, Árpád Berta, Márk Jelasity, Vilmos Bilicki)....Pages 108-115 FOUGERE: User-Centric Location Privacy in Mobile Crowdsourcing Apps (Lakhdar Meftah, Romain Rouvoy, Isabelle Chrisment)....Pages 116-132 On the Performance of ARM TrustZone (Julien Amacher, Valerio Schiavoni)....Pages 133-151 CapBAC in Hyperledger Sawtooth (Stefano Bistarelli, Claudio Pannacci, Francesco Santini)....Pages 152-169 Developing Secure Services for IoT with OP-TEE: A First Look at Performance and Usability (Christian Göttel, Pascal Felber, Valerio Schiavoni)....Pages 170-178 Back Matter ....Pages 179-179