CULTURESAMPO –A Collective Memory of Finnish Cultural Heritage on the Semantic Web 2.0

This paper presents the Semantic Web 2.0 application CULTURESAMPO, an ambitious system of creating a collective semantic memory of the cultural heritage of a nation on the Semantic Web 2.0, combining ideas underlying the Semantic Web and the Web 2.0. The system addresses the semantic challenge of aggregating highly heterogeneous, cross-domain cultural heritage into a semantically rich intelligent system for human and machine users. At the same time, CULTURESAMPO is an approach to solve the social and practical Web 2.0 challenge of organizing the underlying collaborative ontology development and content creation work of memory organizations and citizens. 1 Components of a National Semantic Memory In our view, a cultural heritage memory on the Semantic Web 2.0 should be built on three pillars: First we need a cross-domain content infrastructure of ontologies, metadata standards, and related services, that is developed and maintained on a global level through collaborative local efforts. Second, the process of producing ontologically harmonized metadata should be organized in a collaborative fashion, where distributed content producers are able to create semantically correct annotations cost-efficiently through centralized services. Third, the contents should be made available to human end-users and machines thought intelligent search, browsing, and visualization techniques in a portal. For machines, easy to use mash-up APIs and web services should be available. In this way, the collaboratively aggregated, semantically enriched national memory can be exposed and reused easily as services in other portals and applications in the same vein as Google Ads or Maps. CULTURESAMPO [1], released on the public web on September 25, 2008, is an operational demonstration on a national Finnish level of implementing of such a semantic collective memory. The system consists of three components corresponding to the three pillars above: 1 http://code.google.com/apis/maps/ 2 http://www.kulttuurisampo.fi/ 1. National cross-domain content infrastructure FinnONTO The basis of CULTURESAMPO is the national FinnONTO infrastructure [2, 3] that includes a collaboratively created system of cross-domain ontologies and related ontology services for utilizing them cost-efficiently [4]. The ontologies and the services were released in several languages on the public web as the National Ontology Service ONKI on September 12, 2008. 2. A content creation process Our model consists of a set of metadata models and a content creation process for producing and harvesting content from museums, libraries, archives and other organizations, as well as from individual citizens and Web 2.0 sources, such as Wikipedia and Panoramio. 3. Semantic Web 2.0 portal CULTURESAMPO The portal itself is unique in its use of versatile cross-domain semantic models, new semantic searching and browsing methods, and semantic visualizations for the end-users, for both humans and machines. In the following these three components are explained in more detail. 2 A Collaborative Ontology Infrastructure An integral part of CULTURESAMPO are the ontologies and services of the FinnONTO infrastructure [2, 3]. The general idea of the FinnONTO approach is to extend the generic, logic based W3C recommendations with domain specific ontologies in different domains. Most of the FinnONTO ontologies were developed by transforming nationally used thesauri into light weight ontologies. The process was not mechanical like e.g. in [5], but manual processing was required in order to refine the semantic thesaurus relations into full blown subsumption hierarchies. In the FinnONTO model, the ontologies are developed in a distributed fashion by collaborating expert groups of different fields, and are mapped together to form a large national ontology called KOKO encompassing all domains. At the moment, KOKO includes an upper ontology YSO (20 600 concepts), a museum ontology MAO (6800 concepts), an agriforestry ontology AFO (5500 concepts), an applied art ontology TAO (2600 concepts) and a photography ontology VALO (1900 concepts). The ontologies are provided to end-users not only in the RDF/OWL form, as usual, but as ready to use semantic web widgets [6] using Web 2.0 AJAX APIs, and through conventional Web Services [4]. The KOKO ontology as a single whole is used by developers and end-users, and is the ontological basis of CULTURESAMPO. In addition to KOKO, CULTURESAMPO also utilizes a geographical registry of 800 000 places in Finland, a spatio-temporal ontology of Finnish counties 1865– 2007 [7], an ontology of persons and organizations, and ontologized international systems such as the Iconclass and the Union List of Artists Names (ULAN). 3 http://www.yso.fi/ 4 http://www.wikipedia.org/ 5 http://www.panoramio.com/ 6 http://www.iconclass.nl/ 7 http://www.getty.edu/research/conducting research/vocabularies/ulan/ 3 Content Creation Process CULTURESAMPO contains cultural objects of 26 different content types: artifacts, paintings, drawings, sculpture, abstract art, novels, comics, web pages, three types of folklore, five types of folk music, photos, aerial photos, persons, organizations, biographies, historical events, skills, videos, buildings, and archeological sites. These content types are represented using 16 different metadata schemas. The aggregated knowledge base contains (Sept 26, 2008) 52 267 cultural objects and 234 597 other resources, such as ontological class concepts and place instances. The cultural objects are described by 624 021 property triples. The content is enriched using reasoning, resulting in 5 844 153 property triples. The enriched knowledge base is used for intelligent information retrieval and for creating semantic recommendation links between objects. In addition, there are 1 194 230 pieces of data related to reference resources. The content is represented using RDF and OWL, and SPARQL is used for recommendations. The system also utilizes external web resources: all Wikipedia articles (in English and Finnish) that have coordinate information, as well as photographs from the Panoramio service can be found on CULTURESAMPO’s map views. These information sources have diverse ownerships. The contents come from 21 museums, archives, and libraries, most of which produce their contents independently from each other using heterogeneous cataloging systems and practices, e.g. different vocabularies. Wikipedia and Panoramio content is created internationally by the public. CULTURESAMPO also has an internal commenting facility by which individuals can contribute new knowledge to individual content items, e.g. identify persons in an old photograph of a museum collection. In these ways, citizens are able to contribute to the national semantic memory. Furthermore, interactive content production based on the SAHA editor [8] is being implemented in the system—this content creation channel has already been used internally in the system by participating organizations. From a semantic modeling viewpoint, a research focus of our work has been eventand process-based annotations used in artificial intelligence and knowledge representation [9]. In our case, events have been used for modeling cultural processes and narrative stories [1, 10] and for metadata schema integration [11, 12]. The KOKO ontology was designed to support this by clearly separating events and processes from the other concepts along the model of Dolce [13]. In some metadata schemas of CULTURESAMPO it is possible to annotate content using processes in terms of events, subevents and their sequences; the model in use in the prototype is a simplified version of our earlier model [10]. The portal then automatically generates an interactive representation of the process as a kind of a temporal table of contents. This system is used in the prototype for creating skill descriptions, cultural process description, and documentation of processes in videos: 1. Semantic skill models. An example of a skill model is the model “Production of Ceramics” produced by experts at the University of Applied Arts in Helsinki. It illustrates and explains the composition of different work phases when manufacturing ceramics. At each phase, semantic recommendations to relevant CULTURESAMPO contents can be created. For example, links to products in collections that were manufactured using the same techniques, are automatically obtained. 2. Semantic models of cultural processes. There is a similar kind of chronological model “A Year on a Farm” of the seasonal events and processes taking place at a typical farm in Finland. Again, tools and other materials from CULTURESAMPO are linked automatically with related events. This model was created by a farmer employed at the Finnish Museum of Agriculture. The exhibition of this museum is actually organized using the same idea of presenting farming events taking place during different yearly seasons. 3. Semantic documentation on videos. The annotation model can be applied also to documenting instances of actual skill events or processes documented on a video. The case example available on the portal describes how the shoemaker Onni Wirlander manufactured a pair of traditional leather boots. The video was produced, and the actual annotation created, by the Espoo City Museum using the SAHA editor connected to the ONKI ontology services. The semantic model describes what happens at different (sub)sequences on the video. Semantic search can find not only the video as a black box, as in systems such as YouTube, but also points of interest inside the video. The video can be viewed directly starting from different points of interest. This is important with longer videos. The Wirlander video e.g. lasts over 20 minutes. When watching the video, the recommendation system creates dynamically, for each subsequence separately, recommendation links to materials of interest in the portal, such as tools related to the sequence. The