In MOODS, different preferences may lead musicians to work on the same music by using different views or formatting rules. This means that the information is differently visualized in the several terminal of the cooperative environment.
Provided that there are distinct roles in a group, separate permissions for manipulating the information are assigned to different users. The changes have to be collected according to the configuration of the cooperative system and they are grouped according to the relationships among manipulated symbols in order to make possible the undo mechanism as described in Section 5 of the paper.
A relevant aspect of the cooperative work is to deal with the management of authorization rights to manage music notation symbols. To give full power to all musicians so that they can manipulate notes, rests, measures, beams, slurs, etc., is a unsuitable approach because it is likely to produce chaotic results. According to their configuration and profile, all musicians may modify their set of symbols while heavier changes can be performed or supervised by the archivist on the MASAE station. The Group leaders should be authorized to modify a larger number of music notation symbols than their related lecterns in the same group. In effect, typical scenarios are much more complex since during operas and ballets heavy changes can occur. In such events, the group leader could be delegated to modify music in depth, for example by adding notes which change the music structure in a different way from the light changes performed through adding/deleting, fingering, bowing, mutes, accents, etc.).
To manage these conditions, a specific User Permission profile is defined and assigned to each lectern. It is used for limiting the manipulation of notation symbols and the execution of selected operations such as the deletion of notation symbols. The notation symbols of the music editor have been classified in categories to simplify both the configuration and the comprehension of the mechanism by the musicians. The adopted classification has been carried out on the basis of the results of several questionnaires during the early stage of requirement analysis of MOODS projects. For example, the category of symbols (in the fifth position of the list on the right part of the window depicted in the following Figure) is named clef/key signature/time and includes the insertion and deletion of clefs, key signatures, time signatures; the category of accents includes: tenuto, staccato, martellato, snap, etc.; the category of symbols named strings: bowing, tallone, punta, pizzicato, etc.
The assigned permissions to each lectern to manipulate music can be dynamically changed.
When changes involve the structural part of the music (notes, rests, key signature, etc.)
two distinct approaches could be followed. The first avoids their adoption by unauthorized lecterns.
The second allows their adoption, but the archivist on the MASAE station has to supervise the changes.
This supervisor may validate (accept) or invalidate (discharge) changes.
In the following figure, the ONCM window for defining the profile of MASEs and DLIOOs lecterns is presented.
On the left of the configuration window, the list of already available profiles is reported, while on the right,
the User Permission table is reported. The available profiles can be used either as they are or to produce customized
profiles. The buttons with arrows allow the definition of new profiles and the loading of already defined ones.
By means of the User Permissions table the archivist can specify the notation symbol categories that can be
manipulated (inserted/deleted) by each lectern. The notation symbols and MOODS editor menu are grouped and listed.
Each group can be disabled (when an empty [ ] is present), enabled with no need of validation (with [*]), and enabled
with validation when the item is marked with [v]. For example, in the profile reported in the following figure,
the fingering is disabled, while symbols of violin are allowed without permission and the drum symbols, when inserted,
have to be validated by the archivist. The END button provokes the setting of the permissions selected.
The above User Permissions can be imposed during the configuration, and can be updated in real-time during EDITING.
This possibility allows enabling the adding or deleting of specific symbols on a temporary basis to perform actions
limited in time. The archivist has to control the access to the parts granting to musicians specific access
capabilities such as the ability to add or delete some types of symbols or to add/delete new measures, etc.
For example, a musician may see an incorrect note on the score, and the archivist may delegate that musician
to make this type of change.