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userguide:retentiontimealignment [2010/08/02 13:04] 132.168.74.230 |
userguide:retentiontimealignment [2010/08/02 16:27] (current) 132.168.74.230 |
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- | ===== Major steps followed by the Retention Time algorithm ===== | + | ===== Major steps followed by the Retention Time Alignment algorithm ===== |
{{ :userguide:rtalignmentconcept2.png|}} | {{ :userguide:rtalignmentconcept2.png|}} | ||
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- Compute one (or several) representative value(s) for group1 & group2 for each pair group | - Compute one (or several) representative value(s) for group1 & group2 for each pair group | ||
- Compute linear regression between representative values | - Compute linear regression between representative values | ||
- | - Store linear regression coefficients in identification properties | + | - Store linear regression coefficients & reference context name in identification properties |
===== In more details... ===== | ===== In more details... ===== | ||
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* If several species exist with redundant sequences, the best score species is retained | * If several species exist with redundant sequences, the best score species is retained | ||
- Then, the corresponding sequences are exported in order to be used by the NETPrediction utility | - Then, the corresponding sequences are exported in order to be used by the NETPrediction utility | ||
- | - The predicted NET are converted to retention time using user-defined parameters. | + | - The predicted NET are converted to retention time using user-defined parameters (duration & delay). |
- The user can decide to exclude predicted values too far from the others: | - The user can decide to exclude predicted values too far from the others: | ||
* The average absolute deviation (between RT & predicted RT) is computed and all predicted RT far from this average value about a given user-defined threshold are excluded. | * The average absolute deviation (between RT & predicted RT) is computed and all predicted RT far from this average value about a given user-defined threshold are excluded. | ||
- | - The predicted RT values are stored as properties in the reference species. | + | - The predicted RT values are then stored as properties in the reference species. |
- | - For each identification existing under the reference User context: | + | - For each identification existing under the reference User context (not necessary directly under the reference user context): |
- All the final child species to align are collected | - All the final child species to align are collected | ||
- Several pair groups are created using reference species & species to align. A pair group contains 2 groups of species having same sequence & calculated mass (group1 has species from reference User context and group2 has species to align from identifications). | - Several pair groups are created using reference species & species to align. A pair group contains 2 groups of species having same sequence & calculated mass (group1 has species from reference User context and group2 has species to align from identifications). | ||
- For each group, according the statistical method choosen by the user, one or several representative RT value(s) is(are) calculated. | - For each group, according the statistical method choosen by the user, one or several representative RT value(s) is(are) calculated. | ||
- | * Each 'Group1' always contains one species as the [[userguide:proteingroups|species/protein grouping]] has been executed on the reference context. | + | * Each 'Group1' always contains one species because [[userguide:proteingroups|species/protein grouping]] has been executed on the reference context and suppressed sequence/calculated mass redundancy. |
- | * 'Group2' may contain one or more species. Following statistical methods are available: | + | * 'Group2' may contain one or more species. One or several representative value(s) is(are) calculated from one of following statistical methods: |
- | + | * Average {{ :userguide:rtalignmentconcept3.png|}} | |
- | + | * Median | |
- | + | * Cross-product | |
- | + | * Combined | |
- | {{:userguide:specif_alignement_tr_2.png|}} | + | * Best score |
+ | - Compute linear regression between pair groups | ||
+ | - Store linear regression coefficients (slope/intercept) + reference context name in the identification properties | ||