The Multiple Layer Search tab houses the most comprehensive search in ELAN. Similar to the Single Layer Search tab a Query History is kept, enabling the user to go back and forward a query by clicking the
and respectively. The two modes / and / / are also similar to the second tab. The first new element is the -button. Clicking this button will clear all data of a query.The buttons
and enables you to constrict the minimal and maximal duration of each result. When you click on one of the buttons, a dialog window appears, e.g.:
Here you can enter the minimal or maximal duration as the
total number of milliseconds or in
hours:minutes:seconds.milliseconds. A value of 0 milliseconds or
00:00:00.000 yields as undefined. Searching for annotations with a
maximum duration being less then the minimum duration is impossible.
Hence, entering conflicting values results in an error message
saying that the combination is impossible. After entering a correct
duration, it will be displayed in the corresponding button.
The buttons
and give a dialog similar to that of the previous two buttons. They give the possibility to restrict the annotations in the result to begin after a certain time and end before a certain time. Entering a Begin After-time that is greater than the End Before-time or vice versa results in an error message saying it is impossible. After entering a correct time, it will be displayed in the corresponding button.Beneath the buttons discussed above, you will find a table consisting of white and green fields. Search strings are entered in the white fields while a green field between two non-empty white fields must contain a constraint. The fields on one row give the search strings and constraints to be matched by annotations on one tier. The result of having three rows in the query table is that the search engine may find annotations on three tiers as one hit. Furthermore, it is possible to restrict the search to one (type of) tier for each row by choosing the appropriate option in the pull-down menu on the right of each row.
Let us first take a look at search strings and constraints in one row. If you enter two search strings in two white fields separated by a green field, you must fill in that green field i.e. make a constraint. Right clicking on the green field gives a context menu offering the following constraints:
: between the annotations containing the two search strings, there must be exactly N annotations.
: between the annotations containing the two search strings, there must be more than N annotations.
: between the annotations containing the two search strings, there must be less than N annotations.
: between the annotations containing the two search strings, there must be exactly X milliseconds.
: between the annotations containing the two search strings, there must be more than X milliseconds.
: between the annotations containing the two search strings, there must be exactly X milliseconds.
: there are no constraints.
: clear the current constraint.
When you click on
and there is an empty constraint between two non-empty search string fields, you will get an error message. You will also get an error message if there is an empty search string field and constraint fields between two non-empty search string fields.As we saw earlier the search mechanism on this tab has the possibility to construct a query for up to three tiers. Besides the constraints on annotations on a tier, one can also apply constraints on annotations on different tiers. This means that if the search engine has found an annotation that matches a search string on one tier, the engine looks if the search string for another tier can be matched on another tier while considering the constraint that is between the two search strings.
The top down hierarchy of the rows in the query table does not reflect the hierarchy of the tiers in your data. That means, for instance, that search strings and constraints in the upper query table row may be matched by a child tier of the tier that matches search strings and constraints in the middle query table row.
Right clicking the green field between two search strings gives a context menu with the following constraints:
: the begin time and end time of both annotations are the same:
: part of both annotations overlap. This includes the other options Fully aligned, Left overlap, Right overlap, Surrounding and Within.
before the begin time and end time of the annotation matching the upper search string:
: the begin time and end time of the annotation matching the lower search string lieafter the begin time and end time of the annotation matching the upper search string:
: the begin time and end time of the annotation matching the lower search string lie: the begin time of the annotation matching the lower search string lies before the begintime of the annotation matching the upper search string and end time of the annotation matching the lower search string lies after the end time of the annotation matching the upper search string:
: the begin time of the annotation matching the lower search string lies after the begintime of the annotation matching the upper search string and end time of the annotation matching the lower search string lies before the end time of the annotation matching the upper search string:
: the begin time of the annotation matching a search string lies after the end time of the annotation matching the other search string:
or
: the begin time of the annotations matching the upper search string must lie exactly X milliseconds before the begin time of the annotation matching the lower search string.
: the begin time of the annotations matching the upper search string must lie less than X milliseconds before the begin time of the annotation matching the lower search string.
: the begin time of the annotations matching the upper search string must lie more than X milliseconds before the begin time of the annotation matching the lower search string.
: the begin time of the annotations matching the upper search string must lie exactly X milliseconds before the end time of the annotation matching the lower search string.
: the begin time of the annotations matching the upper search string must lie less than X milliseconds before the end time of the annotation matching the lower search string.
: the begin time of the annotations matching the upper search string must lie more than X milliseconds before the end time of the annotation matching the lower search string.
: the end time of the annotations matching the upper search string must lie exactly X milliseconds before the begin time of the annotation matching the lower search string.
: the end time of the annotations matching the upper search string must lie less than X milliseconds before the begin time of the annotation matching the lower search string.
: the end time of the annotations matching the upper search string must lie more than X milliseconds before the begin time of the annotation matching the lower search string.
: the end time of the annotations matching the upper search string must lie exactly X milliseconds before the end time of the annotation matching the lower search string.
: the end time of the annotations matching the upper search string must lie less than X milliseconds before the end time of the annotation matching the lower search string.
: the end time of the annotations matching the upper search string must lie more than X milliseconds before the end time of the annotation matching the lower search string.
: there are no constraints.
: clear the current constraint.
An example of a Multiple Layer Search with constraints is shown in Figure 6.20:
Because the search mechanism offers the possibility to search for patterns in three tiers and there are possibly three search strings per tier, the search results also consist of nine elements per hit. Instead of presenting a hit in the form of a table it is presented on one line with indicators for tiers and annotations. Figure 6.20 shows the results of the query above. As you can see the tiers in the result are indicated by #1, #2 and #3 corresponding to the upper, middle and lower query table row respectively. The annotations in a tier are surrounded by vertical bars indicating their start and end.
Figure 6.20 also illustrates
what to do if you would like to use both and
in one query: use the .
In places where you would like to have an exact match use the
^
and $
signs to match
the beginning and end of a string (e.g. ^of$
)
otherwise just enter a word for the substring match.
The figure also show how to use a wildcard to match anything.
Instead of using the #
as in the Single Layer
Search, you can use the regular expression .+
to indicate any character (the dot) one or more times (the plus).
See also Appendix A for more on regular
expressions. The NOT(...) construction on the other hand can be used
in the Multiple Layer Search in the same way as describe in Section 6.5.2.
One final but not less important remark concerns the placing
of more and less restrictive search strings. Figure 6.20 shows a very restrictive
search string in the upper row: ^n$
. The less
restrictive, or should we say unrestrictive, search string .+ is in
the middle row. As we saw earlier, the hierarchy of the rows in the
query does not reflect the hierarchy in the data. That means that
the search string ^n$
could also be placed in
the lower row and not affect the outcome of the search. While this
is perfectly true, we advise you to place restrictive search strings
in the left most field on the upper most row possible and the least
restrictive search string in the right most field of the lowest row
possible. The reason for this is the order in which the search
engine considers the search strings in the query. If it finds a
restrictive search string it can filter out all the other
possibilities, but if it finds a less restrictive search string it
has to consider all the matches of this search string. In the
example of Figure 6.20 it is clear
that if ^n$
is in the bottom row, the search
engine first considers all annotations matching
.+
which is in fact all
annotations in the search domain. Because of this, the search takes
much more time than if ^n$
was in the upper
row.