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Register a new userLocal Read-Write Operations in Sensor Networks
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Added by
Ted Herman
Publication date
2008
fields
Informatics Engineering
and research's language is
English
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Designing protocols and formulating convenient programming units of abstraction for sensor networks is challenging due to communication errors and platform constraints. This paper investigates properties and implementation reliability for a emph{local read-write} abstraction. Local read-write is inspired by the class of read-modify-write operations defined for shared-memory multiprocessor architectures. The class of read-modify-write operations is important in solving consensus and related synchronization problems for concurrency control. Local read-write is shown to be an atomic abstraction for synchronizing neighborhood states in sensor networks. The paper compares local read-write to similar lightweight operations in wireless sensor networks, such as read-all, write-all, and a transaction-based abstraction: for some optimistic scenarios, local read-write is a more efficient neighborhood operation. A partial implementation is described, which shows that three outcomes characterize operation response: success, failure, and cancel. A failure response indicates possible inconsistency for the operation result, which is the result of a timeout event at the operations initiator. The paper presents experimental results on operation performance with different timeout values and situations of no contention, with some tests also on various neighborhood sizes.
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The Telex system is designed for sharing mutable data in a distributed environment, particularly for collaborative applications. Users operate on their local, persistent replica of shared documents; they can work disconnected and suffer no network latency. The Telex approach to detect and correct conflicts is application independent, based on an action-constraint graph (ACG) that summarises the concurrency semantics of applications. The ACG is stored efficiently in a multilog structure that eliminates contention and is optimised for locality. Telex supports multiple applications and multi-document updates. The Telex system clearly separates system logic (which includes replication, views, undo, security, consistency, conflicts, and commitment) from application logic. An example application is a shared calendar for managing multi-user meetings; the system detects meeting conflicts and resolves them consistently.
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