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TECHNOLOGY Semantic linking: the future for media archives? with Stefano Cavaglieri, CTO Swiss National Sound Archives S emantic linking is a term coined by Tim Berners-Lee and used to describe a framework of syntax that allows computers to understand complex statements of the kind humans are able to deal with easily. If all the information online were to be accessible through semantic linking, computers would be able to make use of it in much more subtle ways, and this would greatly increase the power of data search and retrieval. While constructing a framework and system for internet-wide semantic linking is a massive and complex undertaking, one area in which it could more readily be implemented is in media archiving. Here it would allow much more versatile and efficient retrieval of media assets, using a far wider range of search criteria. The commercial possibilities opened up by this development would create far greater revenue for holders of media archives. What’s different about semantic linking? Sentences like ‘The Beatles were a popular band from Liverpool’, ‘John Lennon was a member of the Beatles’, ‘Let It Be was recorded by the Beatles’ are easily understood by people. But how can they be understood by computers? Statements are built with syntax rules. The syntax of a language defi nes the rules for building the language statements. But how can 54 | TV-BAY MAGAZINE: ISSUE 89 MAY 2014 Subject Predicate plays Stefano dislikes Chocolate syntax become understandable to computers? This is what the Semantic Web is all about, describing things in a way that computer applications can understand. The Semantic Web is not about links between web pages; instead, it describes the relationships between things (for example, A is a part of B and Y is a member of Z) and the properties of things (such as the format, dimensions, replay speed, equalization, etc.). Berners-Lee puts it like this: ‘If HTML and the Web made all the online documents look like one huge book, RDF (Resource Description Framework), schema, and inference languages will make all the data in the world look like one huge database’. If information about music, events, preservation, and so on could be stored in RDF fi les, intelligent web applications could then collect information from any source, combining the information and presenting it to users in a more meaningful way. This could have the advantage of creating a more relational database-like guarantee for the correctness of query results. Is a Semantic Web just around the corner? The Semantic Web is not a very fast growing technology. One of the reasons for this is the very steep Object Bass guitar is a Musical instrument learning curve. RDF was developed by people with academic backgrounds in logic and artifi cial intelligence, making it very easy for ‘the rest of us’ to understand it. Another is the current lack of standards. RDF is data about data – or metadata. Often RDF fi les describe other RDF fi les. Will it ever be possible to link all these RDF fi les together and build a Semantic Web? The promise of the Semantic Web has raised a number of different expectations. These expectations can be traced to three different perspectives on the Semantic Web. The Semantic Web is portrayed as: ‘A universal library’, to be readily accessed and used by humans in a variety of information use contexts; ‘The backdrop for the work of computational agents’ completing sophisticated activities on behalf of their human counterparts; and ‘A method for federating particular knowledge bases and databases’ to perform anticipated tasks for humans and their agents. Some of the challenges for the Semantic Web include vastness, vagueness, uncertainty, inconsistency, and deceit. Automated reasoning systems will have to deal with all of these issues in order to deliver on the promise of the Semantic Web. It is not very likely that owners of media archives will be able to catalog their multimedia document just by putting an RDF fi le on the Internet.