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<body bgcolor = "#FFFFCC"><basefont face = "Arial"> |
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<h1>CAST: Cluster Affinity Search Technique</h1> <h2>Parameter Information</h2> |
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<hr size = 10> |
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<h2> Sample Selection </h2> |
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The sample selection option indicates whether to cluster genes or experiments. |
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<br> |
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<h2> Distance Metric Selection </h2> |
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This area allows the selection of the metric to be used to assess gene-to-gene |
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or sample-to-sample distances. The initial metric displayed (choosen) corresponds to the global |
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setting in the Multiple Array Viewer's 'Metrics' menu. Alterations to the |
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chosen metric in this dialog will only alter the metric used for the current |
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algorithm run. The global setting in the main 'Metrics' menu will remain unchanged. |
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<br><br> |
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An appendix in the MeV manual describes the distance metrics offered in MeV. |
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<br> |
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<h2>Threshold</h2> |
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The threshold parameter is a value ranging from 0.0 to 1.0 which is used as a |
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cluster affinity threshold. Each expression element will have an affinity for the current cluster being |
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created based on it's relationship to the elements currently in the cluster. If that affinity |
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is greater than the supplied threshold the gene is permitted to be a member of the cluster. |
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<p> |
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Note that thresholds near 1.0 are more stringent and tend to produce many clusters with |
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rather low variability. Conversely, using a lower threshold will produce fewer, more |
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variable clusters. A balance by trail-and-error should be found between these extremes. |
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</p> |
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<p> |
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Note that in the algorithm expression elements are repeatedly tested for their affinity |
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to the cluster being formed. In that way elements can be added or subtracted based on |
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the current cluster membership. |
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<br> |
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<h2> Hierarchical Clustering </h2> |
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This check box selects whether to perform hierarchical clustering on the elements in each cluster |
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created. |
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<br> |
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</basefont> |
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</body> |
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</html> |
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