Definition of Object-Oriented frbr

Foreword

This document contains a comprehensive description of the object-oriented definition of FRBR, a model in the form of a formal ontology interpreting FRBR for specific purposes, as analysed below. The document comprises the following sections:

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  Section 1, The Introduction, describes the rationale, history and methodology of the development of this model.
  
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  Section 2, The Description of the Model, explains the model in context from a functional perspective with the help of a comprehensive graphical representation of all constructs, describes the format conventions for the formal specifications, and lists the complete class and property definitions that make up the model. Whereas the first serves an overall understanding, the second is the reference for the individual declarations. Here a first reading may stop.
  
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  Section 3 describes the mapping of the entity-relationship models of the FRBR family to the object-oriented model FRBR_OO. This section defines the transition from one form to the other, and serves as information for further understanding of the intended meaning of the object-oriented definition. It is also a proof that the object-oriented form is an alternative view of the FRBR family, and a proof of completeness of the object-oriented form with respect to the original.
  
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  Since the object-oriented model reuses, wherever appropriate, large parts of ISO21127, the CIDOC Conceptual Reference Model, section 4 provides a comprehensive list of all constructs used from ISO21127, together with their definitions following version 6.0 maintained by CIDOC. Some of these constructs appear only in the mapping in section 3 and not in section 2, because they are generic in nature.
  
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  Section 5 provides a bibliography.
  
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  Section 6 traces changes that were made in previous versions of the model.
  

1. Introduction

This document is the definition of the object-oriented version of the FRBR¹ family of conceptual models², harmonised with CIDOC CRM, hereafter referred to as FRBR_OO, a formal ontology that captures and represents the underlying semantics of bibliographic information and therefore facilitates the integration, mediation, and interchange of bibliographic and museum information. Such a common view is necessary for the development of interoperable information systems serving users interested in accessing common or related content. Beyond that, it results in a formalisation which is more suited for the implementation of concepts from the FRBR family of conceptual models with object-oriented tools, and which facilitates the testing and adoption of these concepts in implementations with different functional specifications and beyond the library domain. It applies empirical analysis and ontological structure to the entities and processes associated with the bibliographic universe, to their properties, and to the relationships among them. It thereby reveals a web of interrelationships, which are also applicable to information objects in non-bibliographic arenas³.

The FRBR model was designed as an entity-relationship model by a study group appointed by the International Federation of Library Associations and Institutions (IFLA) during the period 1991-1997, it was approved by the IFLA Cataloguing Section in 1997, and was published in 1998. The original entity-relationship definition of FRBR is referred to hereafter as FRBR_ER.

Quite independently, the CIDOC CRM⁴ model was being developed, beginning in 1996, under the auspices of the ICOM-CIDOC (International Council for Museums – International Committee on Documentation) Documentation Standards Working Group. The definition of the CIDOC CRM model was adopted as ISO standard 21127.⁵

The idea that both the library and museum communities might benefit from harmonising their two models was first expressed in 2000, on the occasion of ELAG’s (European Library Automation Group) 24th Library Systems Seminar in Paris. This idea led to the formation, in 2003, of the International Working Group on FRBR/CIDOC CRM Harmonisation, that brings together representatives from both communities with the common goals of: a) Expressing the IFLA FRBR model with the concepts, tools, mechanisms, and notation conventions provided by the CIDOC CRM, and: b) Aligning (possibly even merging) the two object-oriented models thus obtained.

The International Working Group on FRBR/CIDOC CRM Harmonisation, formed in 2003 and chaired by Martin Doerr (ICS FORTH, Greece), Patrick Le Bœuf (BnF, France), and Pat Riva (BAnQ, Canada), is affiliated at the same time to the IFLA FRBR Review Group and the CIDOC CRM Special Interest Group (CRM-SIG). The present definition of FRBR_OO was developed through email exchange among members of the Working Group, and more importantly during a series of meetings.

Version 1.0 of FRBR_OO was finally approved and issued in January 2010; it covered the entities and concepts from FRBR and included an appendix on identifier creation. The focus of later meetings has been to extend the model to fully encompass the published versions of the FRAD and FRSAD models. Version 2.1 is the result of this expansion.

More information on the activities of the Group, minutes of the meetings and all previous versions can be found on http://archive.ifla.org/VII/s13/wgfrbr/FRBR-CRMdialogue_wg.htm and on http://cidoc.ics.forth.gr/frbr_ inro.html.

1.1. Purposes

This model represents FRBR, FRAD and FRSAD through modelling the conceptualisation of the reality behind library practice, as it is apparent from or implicit in the FRBR family of models. It is important to keep in mind that the aim is not to transform the IFLA models into something conceptually different, but to express the conceptualisation of the FRBR family within the object-oriented methodology instead of the entity-relationship methodology. Furthermore, the intention is to identify the common ground that memory institutions share and to exploit it by pursuing the following objectives.

1.1.1. A Common View of Cultural Heritage Information

The main goal is to reach a common view of cultural heritage information with respect to modelling, standards, recommendations, and practices. Libraries and museums are memory institutions – both strive to preserve cultural heritage objects, and information about such objects, and they often share the same users. Besides, the boundary between them is often blurred: libraries hold a number of museum objects and museums hold a number of library objects; the cultural heritage objects preserved in both types of institutions were created in the same cultural context or period, sometimes by the same agents, and they provide evidence of comparable cultural features. It seems therefore appropriate to build a common conceptualisation of the information gathered by the two types of organisations about cultural heritage.

1.1.2. A Verification of FRBR’s Internal Consistency

Expressing the FRBR family in a different formalism than the one in which it was originally developed provides a means to evaluate the models in terms of their internal consistency. It is also a good opportunity to make adjustments to avoid some semantic inconsistencies and imprecisions in the formulation of the FRBR family, which prove to be crucial in the design of an overall model for the integration of cultural heritage related information. Additionally, the clarifications helped in the further development of the FRBR model itself, such as the interpretation of aggregates and aggregating work and understanding the dual nature of Manifestation.

1.1.3. An Enablement of Information Interoperability and Integration

Mediation tools and Semantic Web activities require an integrated, shared ontology for the information accumulated by both libraries and museums for all the collections that they hold, seen as a continuum from highly standardised products such as books, CDs, DVDs, etc., to raw materials such as plants or stones⁶, through “in-between” objects such as draft manuscripts or engraving plates. In addition, such typical “library objects” as books can be about museum objects, and museum objects can represent events or characters found in books (e.g., ‘Ophelia’s death’) and descriptions of museum objects in museum databases may contain references to bibliographic resources that mention those museum objects: such interrelationships should be either integrated in common information storage, or at least virtually integrated through mediation devices that allow a query to be simultaneously launched on distinct information depositories, which requires common semantic tools such as FRBR_OO plugged into CIDOC CRM. Besides, CIDOC CRM is explicitly compatible in formalism with the World Wide Web Consortium’s Resource Description Framework (RDF), which is also beneficial for the IFLA models.

1.1.4. An Opportunity for Mutual Enrichment for the FRBR Family and CIDOC CRM

The CIDOC CRM model is influenced by the process of FRBR’s re-formulation as well. Modelling bibliographic information highlights some issues that may have been overlooked during the development of CIDOC CRM, and the way such issues are addressed in FRBR_OO resulted in some cases in making changes in the CIDOC CRM model. These changes are so significant that a revision of the ISO standard 21127 was required.

1.1.5. An Extension of the FRBR Family and the CIDOC CRM

The harmonisation between the two models is also an opportunity to extend the scope of the CIDOC CRM to bibliographic information, which paves the way for extensions to other domains and formats, such as EAD, TEI, MPEG7, just to name a few. Consequently, it also extends the scope of the FRBR family of conceptual models to cultural materials, since FRBR_OO inherits all concepts of the CIDOC CRM, and opens the way for the IFLA models to benefit from further extensions of the scope of CIDOC CRM, such as the scientific heritage of observations and experiments.

1.1.6. Sources

The main source for the task of translating FRBR into the object-oriented formalism was, quite naturally, the IFLA Final Report that contains the complete definition of FRBR_ER itself:

IFLA Study Group on the functional requirements for bibliographic records. Functional requirements for bibliographic records: final report. Munich, Germany: K. G. Saur, 1998. Also available online from World Wide Web: .

Common awareness of the Definition of the CIDOC Conceptual Reference Model provides the required conceptual and technical background:

ICOM/CIDOC Documentation Standards Group; CIDOC CRM Special Interest Group. Definition of the CIDOC Conceptual Reference Model: version 6.0, January 2015. [Heraklion, Greece]: [ICS-FORTH], 2014. Available online at: , or: .

In the preparation of version 2.1 of FRBR_OO the final approved statements of the FRAD and FRSAD models were used.

IFLA Working Group on Functional Requirements and Numbering of Authority Records (FRANAR); Glenn E. Patton, ed., Functional requirements for authority data: a conceptual model. München: K.G. Saur, 2009. .

IFLA Working Group on the Functional Requirements for Subject Authority Records (FRSAR); Marcia Lei Zeng, Maja Žumer and Athena Salaba, ed., Functional requirements for subject authority data (FRSAD): a conceptual model. Berlin: De Gruyter Saur, 2011. Also available online from World Wide Web: .

1.1.7. Understanding the Attributes and Relationships

The methodology consisted in a thorough examination of all attributes and relationships declared in the FRBR family. During its meetings, the International Working Group on FRBR/CIDOC CRM Harmonisation strove to extract the semantics as accurately as possible, to express them as “properties” in the sense of CIDOC CRM, and to relate them to CIDOC CRM properties where possible. Entities, or classes in the terminology adopted by the CIDOC CRM, play a nearly secondary role as the maximal sets of things for which a property is applicable.

1.1.8. Transforming Attributes into Properties

The CIDOC CRM model declares no “attributes” at all, but regards any information element as a “property” (or “relationship”) between two classes. The semantics extracted from FRBR_ER, FRAD and FRSAD attributes are therefore rendered in FRBR_OO as properties, according to the same principles as the CIDOC CRM model.

1.1.9. By-Product 1: Re-Contextualising Bibliographic Entities

The process of interpreting the precise semantic value of each individual attribute declared in FRBR_ER and expressing that semantic value in CRM-like structures resulted also in two by-products.

The first by-product was that it proved necessary to explain and model the general context within which the bibliographic entities isolated in FRBR_ER come into being. FRBR_ER envisions bibliographic entities as static, ever-existing things that come from nowhere, and overlooks the complicated path from the initial idea for a new work in a creator’s mind to the physical item in a user’s hands through the dramatically important decision-making on behalf of publishers, as this complicated path is not explicitly reflected in data actually stored in bibliographic databases and library catalogues, which constituted the domain of reference of the FRBR Study Group. As a matter of fact, bibliographic records do contain some implicit information about that complicated path and the relationships it implies between and among bibliographic objects; FRBR_OO digs that implicit information out of bibliographic structures, e.g. the precise meaning of “date of publication”.

1.1.10. By-Product 2: Adding a Bibliographic Flavour to CIDOC CRM

The second by-product was that the analysis provided for bibliographic processes in FRBR_OO and for the processes of naming entities in FRAD and FRSAD, paved the way for the introduction of refinements in the CIDOC CRM. This enabled the museum community’s model to give a better account of mass production phenomena (such as the printing of engravings), the relation between creating immaterial content and physical carriers and the practices of identifying or naming things. Further, it introduces a basic model of intellectual conception and derivation applicable to all art forms, which the museum community had been hesitating to formally analyse.