177 results found
Zamyatin A, Harz D, Lind J, et al., XCLAIM: Decentralized, Interoperable, Cryptocurrency-Backed Assets, 40th IEEE Symposium on Security and Privacy (IEEE S&P 2019)
Wu H, Knottenbelt W, Wolter K, 2019, An efficient application partitioning algorithm in mobile environments, IEEE Transactions on Parallel and Distributed Systems, ISSN: 1045-9219
Application partitioning that splits the executions into local and remote parts, plays a critical role in high-performance mobile offloading systems. Mobile devices can obtain the most benefit from Mobile Cloud Computing (MCC) or Mobile Edge Computing (MEC) through optimal partitioning. Due to unstable resources at the wireless network (network disconnection, bandwidth fluctuation, network latency, etc.) and at the service nodes (different speeds of mobile devices and cloud/edge servers, memory, etc.), static partitioning solutions with fixed bandwidth and speed assumptions are unsuitable for offloading systems. In this paper, we study how to dynamically partition a given application into local and remote parts effectively, while keeping the total cost as small as possible. For general tasks (i.e., arbitrary topological consumption graphs), we propose a Min-Cost Offloading Partitioning (MCOP) algorithm that aims at finding the optimal partitioning plan (determine which portions of the application to run on mobile devices and which portions on cloud/edge servers) under different cost models and mobile environments. Simulation results show that the MCOP algorithm provides a stable method with low time complexity which significantly reduces execution time and energy consumption by optimally distributing tasks between mobile devices and servers, besides it well adapts to mobile environmental changes.
Werner S, Pritz P, Zamyatin A, et al., Uncle traps: harvesting rewards in a queue-based ethereumMining Pool, 12th EAI International Conference on Performance Evaluation Methodologies and Tools, Publisher: ACM
Mining pools in Proof-of-Work cryptocurrencies allow miners topool their computational resources as a means of reducing payoutvariance. In Ethereum,uncle blocksare valid Proof-of-Work solu-tions which do not become the head of the blockchain, yet yieldrewards if later referenced by main chain blocks. Mining pool opera-tors are faced with the non-trivial task of fairly distributing rewardsfor both block types among pool participants.Inspired by empirical observations, we formally reconstruct aSybil attack exploiting the uncle block distribution policy in a queue-based mining pool. To ensure fairness of the queue-based payoutscheme, we propose a mitigation. We examine the effectiveness ofthe attack strategy under the current and the proposed policy via adiscrete-event simulation. Our findings show that the observed attackcan indeed be obviated by altering the current reward scheme.
Zamyatin A, Harz D, Lind J, et al., 2018, XCLAIM: A Framework for Blockchain Interoperability
Building trustless cross-blockchain trading protocols is challenging. Centralized exchanges thus remain the preferred route to executing transfers across blockchains. However, these services require trust and therefore undermine the very nature of the blockchains on which they operate. To overcome this, several decentralized exchanges have recently emerged which offer support for atomic cross-chain swaps (ACCS). ACCS enable the trustless exchange of cryptocurrencies across blockchains, and are the only known mechanism to do so. However, ACCS suffer significant limitations; they are slow, inefficient and costly, meaning that they are rarely used in practice.We present XCLAIM: the first generic framework for achieving trustless and efficient cross-chain exchanges using cryptocurrency-backed assets (CbAs). XCLAIM offers protocols for issuing, transferring, swapping and redeeming CbAs securely in a non-interactive manner on existing blockchains. We instantiate XCLAIM between Bitcoin and Ethereum and evaluate our implementation; it costs less than USD 0.50 to issue an arbitrary amount of Bitcoin-backed tokens on Ethereum. We show XCLAIM is not only faster, but also significantly cheaper than atomic cross-chain swaps. Finally, XCLAIM is compatible with the majority of existing blockchains without modification, and enables several novel cryptocurrency applications, such as cross-chain payment channels and efficient multi-party swaps.
Stewart I, Ilie D, Zamyatin A, et al., 2018, Committing to quantum resistance: a slow defence for Bitcoin against a fast quantum computing attack, ROYAL SOCIETY OPEN SCIENCE, Vol: 5, ISSN: 2054-5703
Zamyatin A, Harz D, Knottenbelt WJ, 2018, Issue, Trade, Redeem: Crossing Systems Bounds with Cryptocurrency-Backed Tokens., IACR Cryptology ePrint Archive, Vol: 2018, Pages: 643-643
Harz D, Knottenbelt WJ, 2018, Towards Safer Smart Contracts: A Survey of Languages and Verification Methods., CoRR, Vol: abs/1809.09805
, 2018, Companion of the 2018 ACM/SPEC International Conference on Performance Engineering, ICPE 2018, Berlin, Germany, April 09-13, 2018, Publisher: ACM
, 2018, Proceedings of the 2018 ACM/SPEC International Conference on Performance Engineering, ICPE 2018, Berlin, Germany, April 09-13, 2018, Publisher: ACM
Zamyatin A, Stifter N, Judmayer A, et al., 2018, (Short Paper) A Wild Velvet Fork Appears! Inclusive Blockchain Protocol Changes in Practice., Pages: 87-87
Zamyatin A, Stifter N, Schindler P, et al., 2018, Flux: Revisiting Near Blocks for Proof-of-Work Blockchains., IACR Cryptology ePrint Archive, Vol: 2018, Pages: 415-415
Pesu T, Kettunen J, Knottenbelt WJ, et al., 2017, Three-way optimisation of response time, subtask dispersion and energy consumption in split-merge systems, Pages: 244-251
© 2017 ACM. This paper investigates various ways in which the triple trade-off metrics between task response time, subtask dispersion and energy can be improved in split-merge queueing systems. Four ideas, namely dynamic subtask dispersion reduction, state-dependent service times, multiple redundant subtask service servers and restarting subtask service, are examined in the paper. It transpires that all four techniques can be used to improve the triple trade-off, while combinations of the techniques are not necessarily beneficial.
Mora SV, Knottenbelt WJ, 2017, Deep Learning for Domain-Specific Action Recognition in Tennis, 30th IEEE/CVF Conference on Computer Vision and Pattern Recognition Workshops (CVPRW), Publisher: IEEE, Pages: 170-178, ISSN: 2160-7508
Zamyatin A, Wolter K, Werner S, et al., 2017, Swimming with Fishes and Sharks: Beneath the Surface of Queue-based Ethereum Mining Pools, 25th IEEE International Symposium on Modeling, Analysis, and Simulation of Computer and Telecommunication Systems (MASCOTS), Publisher: IEEE COMPUTER SOC, Pages: 99-109, ISSN: 1526-7539
Pesu T, Knottenbelt WJ, 2017, Optimising hidden stochastic PERT networks, Pages: 133-136
Copyright © 2016 EAI. This paper introduces a technique for minimising subtask dispersion in hidden stochastic PERT networks. The technique improves on existing research in two ways. Firstly, it enables subtask dispersion reduction in DAG structures, whereas previous techniques have only been applicable to single-layer split-merge or fork-join systems. Secondly, the exact distributions of subtask processing times do not need to be known, so long as there is some means of generating samples. The technique is further extended to use a metric which trades off subtask dispersion and task response time.
Harrison PG, Patel NM, Knottenbelt WJ, 2016, Energy--Performance Trade-Offs via the EP Queue, ACM Transactions on Modeling and Performance Evaluation of Computing Systems, Vol: 1, Pages: 1-31, ISSN: 2376-3639
Tsimashenka I, Knottenbelt WJ, Harrison PG, 2016, Controlling variability in split-merge systems and its impact on performance, ANNALS OF OPERATIONS RESEARCH, Vol: 239, Pages: 569-588, ISSN: 0254-5330
Haughian G, Osman R, Knottenbelt WJ, 2016, Benchmarking Replication in Cassandra and MongoDB NoSQL Datastores, 27th International Conference on Database and Expert Systems Applications (DEXA), Publisher: SPRINGER INT PUBLISHING AG, Pages: 152-166, ISSN: 0302-9743
Wu H, Knottenbelt WJ, Wolter K, et al., 2016, An Optimal Offloading Partitioning Algorithm in Mobile Cloud Computing., Publisher: Springer, Pages: 311-328
Kelly J, Knottenbelt WJ, 2016, Does disaggregated electricity feedback reduce domestic electricity consumption? A systematic review of the literature., CoRR, Vol: abs/1605.00962
Pesu T, Knottenbelt WJ, 2015, Dynamic Subtask Dispersion Reduction in Heterogeneous Parallel Queueing Systems, ELECTRONIC NOTES IN THEORETICAL COMPUTER SCIENCE, Vol: 318, Pages: 129-142, ISSN: 1571-0661
Parson O, Fisher G, Hersey A, et al., 2015, Dataport and NILMTK: A Building Data Set Designed for Non-intrusive Load Monitoring, IEEE Global Conference on Signal and Information Processing (GlobalSIP), Publisher: IEEE, Pages: 210-214
Chen X, Knottenbelt WJ, 2015, A performance tree-based monitoring platform for clouds, Pages: 97-98
Copyright © 2015 ACM. Cloud-based software systems are expected to deliver reli- able performance under dynamic workload while eficiently managing resources. Conventional monitoring frameworks provide limited support for exible and intuitive performance queries. In this paper, we present a prototype monitor- ing and control platform for clouds that is a better fit to the characteristics of cloud computing (e.g. extensible, user- defined, scalable). Service Level Objectives (SLOs) are ex- pressed graphically as Performance Trees, while violated SLOs trigger mitigating control actions.
Chen X, Rupprecht L, Osman R, et al., 2015, CloudScope: Diagnosing and Managing Performance Interference in Multi-Tenant Clouds, 23rd International Symposium on Modeling, Analysis, and Simulation of Computer and Telecommunication Systems (MASCOTS), Publisher: IEEE, Pages: 164-173, ISSN: 1526-7539
Bradley J, Knottenbelt W, Thomas N, 2015, Preface, Electronic Notes in Theoretical Computer Science, Vol: 310, Pages: 1-3, ISSN: 1571-0661
Kelly J, Knottenbelt WJ, 2015, Neural NILM: Deep Neural Networks Applied to Energy Disaggregation., Publisher: ACM, Pages: 55-64
, 2015, An Optimal Offloading Partitioning Algorithm in Mobile Cloud Computing., CoRR, Vol: abs/1510.07986
Nika M, Wilding T, Fiems D, et al., 2015, Going Multi-viral: Synthedemic Modelling of Internet-based Spreading Phenomena., ICST Trans. Ambient Systems, Vol: 2, Pages: e4-e4
, 2015, Computer Performance Engineering - 12th European Workshop, EPEW 2015, Madrid, Spain, August 31 - September 1, 2015, Proceedings, Publisher: Springer
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