Definition of Object-Oriented frbr

1.2. Differences between FRBR_ER and FRBR_OO

1.2.1. Introduction of Temporal Entities, Events, and Time Processes

Temporal entities (i.e., phenomena, “perdurants” in philosophy) play a central role in the CIDOC CRM model, as they are the only means to relate objects (either conceptual or physical) to time-spans, locations, and agents. Since FRBR_OO borrows structures from the CIDOC CRM to express the concepts declared in FRBR_ER, “temporal entities” had inevitably to be introduced into FRBR_OO. Besides, some FRBR commentators had already made the point that time issues are insufficiently addressed in FRBR_ER;⁷ the task of harmonising FRBR with the CIDOC CRM was an opportunity to fix that. Temporal entities were introduced into FRBR_OO by declaring some of the classes of FRBR_OO as subclasses of the following classes from CIDOC CRM: E65 Creation, E12 Production, E7 Activity, and E13 Attribute Assignment.

Figure 1 shows how the classes F27 Work Conception and F28 Expression Creation serve to link an E39 Actor, an E52 Time-Span and an E53 Place to the F1 Work, F2 Expression and F4 Manifestation Singleton that are created by those processes. In the lower part of the figure the work elaboration process is shown along a time axis. First, the activity F27 Work Conception produces an idea, then the F28 Expression Creation activity produces simultaneously an F2 Expression and its first manifestation (in the form of a F4 Manifestation Singleton), which together realise a work (F1).

Figure

1.2.2. Refinement of Group 1 Entities

The text of FRBR_ER in some cases admits of multiple interpretations which introduce some logical inconsistencies, in particular with regard to its “Group 1 entities,” those entities that account for the content of a catalogue record.

The Work entity such as defined in FRBR_ER seemed to cover various realities with distinct properties. While the main interpretation intended by the originators of FRBR_ER seems to have been that of a set of concepts regarded as commonly shared by a number of individual sets of signs (or “Expressions”), other interpretations were possible as well: that of the set of concepts expressed in one particular set of signs, independently of the materialisation of that set of signs; and that of the overall abstract content of a given publication. FRBR_OO retains the vague notion of “Work” as a superclass for the various possible ways of interpreting the FRBR_ER definitions: F14 Individual Work corresponds to the concepts associated to one complete set of signs (i.e., one individual instance of F22 Self-Contained Expression); F19 Publication Work comprises publishers’ intellectual contribution to a given publication; and F15 Complex Work is closer to what seems to have been the main interpretation intended in FRBR_ER. Additionally, a further subclass is declared for F1 Work: F16 Container Work, which provides a framework for conceptualising works that consist in gathering sets of signs or fragments of sets of signs, of various origins (“aggregates”). Just like any product of the human mind, a Work necessarily begins to exist in the material world at a given point in time; this is the reason why FRBR_OO introduces the notion of F27 Work Conception. It makes the meaning of the FRBR_ER attribute ‘4.2.3 date of Work’ explicit, and accounts for the relationship between a Work and its creator, which holds even in cases when that creator has no direct participation in the creation of the Expression of that Work which is being catalogued (e.g., in the case of translations).

The Expression entity is relatively clear in FRBR_ER, at least from a purely conceptual point of view. However, the need was felt for a distinction between expressions that convey the complete idea of the work they realise, and expressions that convey only a fragment of it: that is, between instances of F22 Self-Contained Expression and instances of F23 Expression Fragment.

The Manifestation entity was defined in FRBR_ER in such a way that its definition could be interpreted as covering something physical and conceptual at the same time: it was defined in turn as the “physical embodiment” of an expression of a work and as an entity that represents all the physical objects that bear the same characteristics. Discussion with members of the original FRBR Study Group⁸ showed that the Manifestation entity was actually meant as an entity all instances of which are sets; and sets, in the mathematical sense of the term, can have more than one member, or just one member (in which case they are called singletons). For the sake of clarification, the Working Group felt the need to split the Manifestation entity into two distinct classes, corresponding to the two possible ways of interpreting the ambiguous definition provided for Manifestation in FRBR_ER, namely F3 Manifestation Product Type and F4 Manifestation Singleton. Whereas F3 Manifestation Product Type is declared as a subclass of the CIDOC CRM class E55 Type, and therefore as a subclass, too, of the CIDOC CRM class E28 Conceptual Object (a merely abstract notion), F4 Manifestation Singleton is declared as a subclass of the CIDOC CRM class E24 Physical Man-Made Thing, and therefore as a subclass, too, of the CIDOC CRM class E18 Physical Thing.

The Item entity did not pose any particular problem in FRBR_ER; but splitting Manifestation into F3 Manifestation Product Type and F4 Manifestation Singleton obliged the Working Group to rethink the articulation between F4 Manifestation Singleton and F5 Item.

All in all, here is a picture of how original FRBR_ER entities relate to the classes declared in FRBR_OO:

Figure
Figure 2 shows how the original FRBR_ER entities relate to the classes declared in FRBR_OO, particularly the “split” of the FRBR_ER Manifestation entity into F3 Manifestation Product Type and F4 Manifestation Singleton. In addition, the figure also shows how FRBR_OO makes explicit the publisher’s intellectual contribution, which is not modelled in FRBR_ER. Manifestation Product Type embodies a Publication Expression, which in turn comprises both the author’s Expression and the realisation of a Publication Work.

In figure 3 the FRBR_OO model of the realisation of a work by an expression is illustrated with a specific example. The overall work is Walt Whitman’s Leaves of grass (an instance of F15 Complex Work), which has as a member the “deathbed edition,” itself an instance of F15 Complex Work. The F14 Individual Work which corresponds to the abstract content of the French translation by Léon Bazalgette of that edition is in turn a member of the F15 Complex Work of the “deathbed edition.” The F28 Expression Creation event which produced the translation simultaneously created a realisation of that translation and created the instance of F22 Self-Contained Expression which is the text of that translation.

Figure

While it can be said that the attributes in FRBR_ER still reflect to a certain degree traditional cataloguing policy, this is no longer true in FRBR_OO. Actually, what a bibliographic record should cover, following the intentions of FRBR, depends on the nature of the thing described, and, to a lesser degree, on the cataloguing policy that was followed when creating it. Interpreting FRBR, FRBR_OO strictly associates attributes (or “properties”) with the entity of the bibliographic discourse they actually belong to. Only this form allows for the explanation and reconciliation of the various application dependent simplifications a particular implementation might choose. Some prominent cases are:
When a national bibliographic agency creates a single record for both hardcover and paperback presentations of the same content, that record describes an instance of F24 Publication Expression, and two distinct instances of F3 Manifestation Product Type. But if a library that only holds a copy of, say, the hardcover edition, decides to retain in the record exclusively such information elements which pertain to that edition, then the record can be said to focus on an instance of F3 Manifestation Product Type.

In the case of electronic publishing, since there is no instance of F3 Manifestation Product Type involved (see below, 1.2.3), the bibliographic record can only describe an instance of F24 Publication Expression.

In the case of serials, since the scope note for F18 Serial Work indicates that “there is in general no single Expression or Manifestation representing a complete serial work, unless the serial work has ended,” what the bibliographic record describes is actually an instance of the F18 Serial Work itself. Information elements that, in the FRBR_ER conceptualisation, were directly attached to the Expression and Manifestation entities, are in FRBRoo seen as being in reality part of the issuing rule for the serial work (represented as an instance of E29 Design or Procedure). It is at the very core of the definition of F18 Serial Work that it plans that issues are published by a particular publisher and contain texts in a particular form. However, those information elements may change over time while the serial work retains its identity; in that case, the instance of F18 Serial Work has several distinct issuing rules over time, a case not modelled in FRBR_ER. This is what is meant when a single bibliographic record shows that at a given date, the publisher and/or place of publication have changed.

Any mapping from an existing database to FRBR_OO should take all these notions into account.

1.2.3. Analysis of Creation and Production Processes

It proved necessary to analyse creation and production processes, in order to enable a better understanding of interrelations and temporal order.

In particular, the notion of “first externalisation” of a set of signs or expression (and, through the expression, the first externalisation of the individual work realised in the expression) is fully modelled in FRBR_OO. It is regarded at the same time as a subclass of the creation of something conceptual, and the production of something physical, because the creation of an expression inevitably also affects the physical world, as the recording of the expression causes a physical modification of the object on which it is being recorded. The spatio-temporal circumstances under which the expression is created are necessarily the same spatio-temporal circumstances under which the carrier of the newly created expression is produced. This double phenomenon of conceptual creation/physical production can be represented by the schema presented in figure 4. F28 Expression Creation, which is a subclass of E65 Creation, produces, on the conceptual level, an F14 Individual Work through the property R19 created a realisation of, and through R17 created, the F22 Self-Contained Expression which realises that work. Operating simultaneously on the physical level, F28 Expression Creation, a subclass of E12 Production, produces, through R18 created, the F4 Manifestation Singleton which P128 carries the F22 Self-Contained Expression.

Figure

Another topic that is modelled in FRBR_OO is the distinction that has to be made between the process of physical publishing and the process of electronic publishing which is illustrated in figure 5. The F5 Items created through physical publishing are the results of an industrial process. As such they are produced by an F32 Carrier Production Event and carry an F24 Publication Expression, yet are also examples of an F3 Manifestation Product Type which CLR6 should carry the F24 Publication Expression. In electronic publishing, in contrast, the instances of F53 Material Copy, which are copies on local carriers, still carry the F24 Publication Expression and are produced by an F32 Carrier Production Event without there being any F3 Manifestation Product Type involved in the process. The instances of E29 Design or Procedure involved in the two processes differ: for physical publishing it can be characterised as “how to produce,” while for electronic publishing as “how to download.”

Figure