Continuous Sampling from Distributed Database

Marzia Ahmed Jui (090232)

Nazmul Hossain Bilash (090236)

11th November, 2012

Distributed DatabaseSamplingContinuous Distributed StreamingSliding WindowProblems DefinitionBinary Bernoulli SamplingThreshold ProtocolSteps for sampling replacementConclusion

OverviewOverview

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Logically interrelated database Distributed over a computer network

Distributed DatabaseDistributed Database

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Statistical method Obtain representative data or observations from a group.

SamplingSampling

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Random Sampling Distinct Sampling Concise Sampling Counting Sampling Priority Sampling

Continues…Continues…

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Continuous track some functions at a design coordinators.

Continuous Distributed StreamingContinuous Distributed Streaming

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Sequence-Based windows. Time Based windows. Time based windows are more difficult to handle.

Sliding WindowSliding Window

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Primary Concern : Total communication cost between the coordinator & sites.

No direct communication allowed between them Reservoir Sampling Problem Current value of total number of element is unknown

Problems DefinitionProblems Definition

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Implementing random sampling Makes the sampling protocols more convenient Do not need to materialize each bit string

Binary Bernoulli SamplingBinary Bernoulli Sampling

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Initiated by a message to begin. Identifies the moment when new elements arrived across all

sites.

Threshold ProtocolThreshold Protocol

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Level Sampling at sites Collection of sample element Production of a sample

Steps for sampling replacementSteps for sampling replacement

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Works for arrival distribution Stochastic Streaming

ConclusionConclusion

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Thank You

Any Questions?