"Who's that?" is a phrase that I often use in the context of my professional life. I should explain that I am something of an anachronism as I work permanent nights as a psychiatric nurse while many trusts are exploring the concept of internal rotation in order to reduce the alienation and deleterious health effects which are common amongst night staff (please refer to Arendt, 2001, in the first instance).

I generally prefer not to know the specific workings of the organisation for which I work. This is a conscious decision on my part as, at this stage in my career, I choose to concentrate on my professional and academic development without the distraction offered by the politicking which is rife within any organisation - no matter its size. This does however mean that the aforementioned phrase is commonly used when I am confronted with the results of decisions made by those in higher positions within the organisation and seek to appreciate just what their role within that organisation is. When I ask, "Who's that?" I don't merely want to know their name but also their position within the hierarchy and from whence their authority springs.

This situation, combined with the experience of explaining the organisation to patients and carers in order to facilitate their negotiation with the same, was the spur behind this dissertation. I came to appreciate that I am not the only one in such a position of ignorance, whether self-imposed or not. After further consideration I also came to see that a tool which would give users the ability to visualise the structure of an organisation and that would also place specific individuals within that structure would be of use not only in my workplace but in many other areas, most particularly in realms such as in inter-business communication.

Thus, this dissertation will focus on the development of an ontology of the specific NHS Trust which employs me and will look at the solutions which are available to facilitate the visual description of it. This will be by no means the sole deliverable of the project but will serve as a starting point which will inform the development of a tool which will reference that visual description within the context of textual communication originating from the organisation. In more formal terms I seek to create a tool which will offer an indication of an individual's position within an organisation from a hypertext based communiqué. This means that it will be possible for a user to reference an organisation map and see the position within that organisation of a person mentioned on a web-page by clicking on that individual's name.

An ontology will be developed because, to some extent, I am in the same position as a computer when confronted by the mass of information on the internet. An excellent analogy was developed by Bechhoffer et al (2003) in their excellent Tutorial on OWL. While html - with its markup consisting primarily of rendering instructions and hyperlinks - allows the human user to understand the semantic content (that is the meaning behind the data) of a web-page, a computer can see no meaning to that content, seeing merely a page of ANSI text. XML can provide meaningful tags to a web-page by, for instance, putting date and author tags to the information but an ontology can provide a computer with some understanding to the tags, allowing the machine to make distinctions and judgements between author, editor or creator tags.

I will first examine the techniques presently used for the description of a field of knowledge - or an ontology - before using that investigation to inform the creation of the ontology.