To provide high availability in distributed systems, object replicas allow concurrent updates. Although replicas eventually converge, they may diverge temporarily, for instance when the network fails. This makes it di...
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ISBN:
(纸本)9783030449148;9783030449131
To provide high availability in distributed systems, object replicas allow concurrent updates. Although replicas eventually converge, they may diverge temporarily, for instance when the network fails. This makes it difficult for the developer to reason about the object's properties, and in particular, to prove invariants over its state. For the subclass of state-based distributed systems, we propose a proof methodology for establishing that a given object maintains a given invariant, taking into account any concurrency control. Our approach allows reasoning about individual operations separately. We demonstrate that our rules are sound, and we illustrate their use with some representative examples. We automate the rule using Boogie, an SMT-based tool.
We study a proof methodology for verifying the safety of data invariants of highly-available distributedapplications that replicate state. The proof is (1) modular: one can reason about each individual operation sepa...
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ISBN:
(纸本)9781450362764
We study a proof methodology for verifying the safety of data invariants of highly-available distributedapplications that replicate state. The proof is (1) modular: one can reason about each individual operation separately, and (2) sequential: one can reason about a distributedapplication as if it were sequential. We automate the methodology and illustrate the use of the tool with a representative example.
Named Data Networking (NDN), a promising Future Internet Architecture design, requires new experimental applications to demonstrate its performance and feasibility. Through designing, implementing, and evaluating NDNM...
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ISBN:
(纸本)9781509044573
Named Data Networking (NDN), a promising Future Internet Architecture design, requires new experimental applications to demonstrate its performance and feasibility. Through designing, implementing, and evaluating NDNMaze, i.e., an NDN version of a widely deployed peer-to-peer file-sharing application called IPMaze, we find that NDNMaze has a simpler system architecture with improved performance and flexibility. The innovative messaging mechanism and distributed hash tables (DHT) in NDNMaze simplified the implementations of key system components such as user management, nearest neighbor discovery, file discovery and distributions. To systematically evaluate the performance, we simulate both versions with NS-3 simulator, and collect a broad range of performance metrics including hop count, data request latency, data request efficiency, and network transmission efficiency. Our experimental results show that NDNMaze achieves better performance than IPMaze due to the NDN's advantages in content-centric data distribution and sharing. Our work sheds light for distributed application design in NDN.
Although platform-independence is a central property in MDA models, the study of platform independence has been largely overlooked in MDA. As a consequence, there is a lack of guidelines to select abstraction criteria...
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ISBN:
(纸本)0769522149
Although platform-independence is a central property in MDA models, the study of platform independence has been largely overlooked in MDA. As a consequence, there is a lack of guidelines to select abstraction criteria and modelling concepts for platform-independent design. In addition, there is little methodological support to distinguish between platform-independent and platform-specific concerns, which could be detrimental to the beneficial exploitation of the PIM-PSM separation-of-concerns adopted by MDA. This paper is an attempt towards clarifying the notion of platform-independent modelling in MDA development. We argue that each level of platform-independence must be accompanied by the identification of an abstract platform. An abstract platform is determined by the platform characteristics that are relevant for applications at a certain level of platform-independence, and must be established by balancing various design goals. We present some methodological principles for abstract platform design, which forms a basis for defining requirements for design languages intended to support platform-independent design. Since our methodological framework is based on the notion of abstract platform, we pay particular attention to the definition of abstract platforms and the language requirements to specify abstract platforms. We discuss how the concept of abstract platform relates to UML.
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