Technology ◊ Photography ◊ Still not driven to drink
It seems that everyone has to put up with nonsense in some form or another. Some days I feel like I am being targetted with more than my fair share of it, but I guess that I probably give as good as I get. Now James Robertson has handily explained the Three Laws Of Nonsense.
RDF and Semantic Web Forum - Wadham College, Oxford, 30th July 2003
A day of presentations and debate on Semantic Web technologies. Speakers include Kal Ahmed, Matt Biddulph, Tony Coates, Libby Miller,
and Ann Wrightson and the day is chaired by the inimitable Peter Flynn. It promises to be a fun and interesting day!
Extreme Markup 2003 - Montréal, 4-8 August 2003
Kal Ahmed will be delivering his paper on Topic Map Design Patterns.
XML USA 2003 - Philadelphia, 7-12 December 2003
Techquila will be presenting a paper on topic map design patterns for information architecture.
Update! - Kal Ahmed will be giving the tutorial "Creating Topic Map Applications Using Open Source Tools" at XML USA 2003. This is a practical tutorial on creating, maintaining and publishing topic maps with tools such as TM4J and TMTab.
I'll be presenting a new paper, "Beyond PSIs - Topic Map Design Patterns" at Extreme Markup Lanuages 2003. For those readers who haven't had the pleasure of attending an Extreme, it is four days of hard-core markup geekery. Much fun and well worth a trip. Details on the paper follow...
Software design patterns give programmers a high level language for discussing the design of software applications. For topic maps to achieve widespread adoption and improved interoperability, a set of topic map design patterns are needed to codify existing practices and make them available to a wider audience. Combining structured descriptions of design patterns with Published Subject Identifiers would enable not only the reuse of design approaches but also encourage the use of common sets of PSIs. This paper presents the arguments for developing and publishing topic map design patterns and a proposed notation for diagramming design patterns based on UML. Finally, by way of examples, the paper presents some design patterns for representation of traditional classification schemes such as thesauri, hierarchical and faceted classification.
As usual, the paper will go up on this site in the near future. The examples are in fact already on this site, in the paper Topic Map Patterns For Information Architecture.
Recent discussion on the topicmapmail mailing list has been on the creation and maintenance of Published Subject Indicators (PSIs). A PSI is a resource which describes a vocabulary (or part of a vocabulary) and provides URIs for terms in the vocabulary (called Published Subject Identifiers which confusingly then has the same acronym, PSI). The discussion has been provoked by the proposal to create a registry of PSIs - a task which I personally welcome.
It seems to me that there are at least two different issues here. One is about the creation of PSIs and the other is about raising the profile of a particular set of PSIs.
First of all lets understand that there is nothing magic about a PSI in its technical aspects. Its just a URI that points to a resource that describes a vocabulary. The "magic" (if there is any) is in the processes that surround the maintenance of the PSI. The publisher that makes a PSI available is supposed to make a commitment to the stability of that PSI.
So what does stability mean ? I think that it means two things:
1) Stability of presence - the PSI's URI is not going to go away within some meaningful time frame (although I hear discussions of stability over hundreds of years, my feeling is that in this business aiming for stability over a period of 5-10 years is a sufficiently Herculean task to gain the status of PSI)
2) Stability of meaning - that the PSI's URI will always be dereferenced to a description of a term that is consistent throughout the lifetime of the PSI (Not necessarily the same all the time - e.g. a PSI for a person might be continually updated to reflect his changing status - marriage, promotion, publications and so on)
Now, neither of these commitments require a large investment in resources for those folks from the typical sem web community (it does leave out a large chunk of the world, but that is an issue that the IT industry as a whole must address). Nor do either of these commitments impose any constraints on users of the PSI. As a user of a PSI I am free to make my own value judgments about the stability of a PSI, and balance them against my judgment of its usefulness to me and the community that I am addressing with my applications. I may be uncomfortable using a PSI created by an individual whom I do not know, I may be uncomfortable using a PSI created by any individual, I may be unwilling to use a PSI created by a particular standards body or by a group I percieve as being unreliable (for whatever reason). The fact that ISO, OASIS, or the Spanish Knitting Association have put their imprimateur on a PSI is simply a factor in my judgement about the usefulness of this PSI to me.
There are good examples on the Web of vocabularies created by committe and by community. MARC is a committee-led vocabulary, as is HL7 and any number of XML vocabularies - created by a formal group (perhaps a public and inclusive group, perhaps a private and closed group) and a formal process.
Community-led vocabularies grow more organically from a user base - for example the Friend Of A Friend vocabulary (FOAF) has grown both in terms of its use and indeed its size as users get interested in applying it. The same could be said for the many faces of RSS.
In general, it seems to me that successful community-led vocabularies are smaller in size and more tightly focussed in scope than committee-led vocabularies. In addition, with no organisational imprimateur to fall back on, community-led vocabularies survive or die on their uptake. Thats not to say that the same dynamics do not also apply to committee-led vocabularies, but the organisation can provide some stability against the tide of user opinion.
So in measurement of stability, a community-led vocabulary can be as stable as a committee-led vocabulary and when one considers the other factors in the choice of vocabulary, the lighter weight, tighter focus and the ability to participate as a member of the user community may make a community-led vocabulary more attractive to some users.
Next we come to the issue of publicising a PSI. PSIs could be gathered together in a number of ways using existing web technology:
1) A centralised repository of PSIs - all subject descriptors are placed in a repository under a single common base URI. Some management process determines which PSIs are published and which are rejected.
2) A centralised registry of PSIs - PSI meta data is stored in a repository with a known address and a search interface which enables PSIs of interest to be located (either by human or machine users). A management process may be used to determin which PSIs are published, but it is not necessary in this case.
3) Informal publication - PSIs are announced on mailing lists and in weblogs or through other informal publication channels. Perhaps the author of a set of PSIs writes some articles on them, or publicises them through their use in a project with public visibility.
4) Search - PSI resources are flagged in some way (perhaps a specific META tag in the HTML representation of the resource) which enables an aware search engine to determine that a page is a resource containing Published Subject Indicators.
There are probably some other ways too. It is true that some of these forms are more restrictive than others for the creators of PSIs - particularly (1) which involves a process which could be open to abuse or to the perception of abuse. But what about the users ? Again I believe we come to the issue of choice. Some users will only be comfortable with PSIs from a centralised repository - some may even be required to use those PSIs because of their toolset. But without choice in the matter, the Semantic Web will be a poorer place. Imagine the Web if Yahoo were the only search engine (or if Google were the only search engine, if Yahoo is your preference...). Diversity causes difficulties for some - and this is an opportunity for an enabling organisation such as OASIS to define the management structures for a centralised repository, or for an enterprising vendor to create such a repository as fits with their tool set. But with the SemWeb in its current nascent state, diversity is to be welcomed and the opportunity for all to participate as both publishers and users of PSIs is vital to its success. That is why I welcome recent proposals to create an open-source registry of PSIs with minimal management processes and look forward to participating in its development as a contributor and as a user.
Blogstipation (n.) - the inability to write any new blog entries. Usually based on the justified belief that one has nothing interesting to say. c.f. this blog.
Blogorreah (n.) - the incessant blogging of stuff that no one finds in the slightest bit interesting. c.f. most blogs everywhere.
I have spent the day in the company of a gaggle of Mac users (is 'gaggle' the correct collective term ?). They made me quite jealous with Hydra a collaborative editing tool in which users not only share documents but can work on them simultaneously. It makes things like collective to-do lists or meeting minutes really easy.
So far I haven't been able to find anything similar for my collection of Windows/Linux boxes.
At last! An excuse to by a Mac !
There are crazier notions, but perhaps it could be that people writing down what they know and other people reading it could be a way for them to communicate.
Nah, surely not.
A new paper has been added to the Publications section of the site. Topic Map Patterns For Information Architecture presents design patterns for modelling some common information organisation constructs from the world of Information Architecture. The paper presents and explains models for hierarchical and facetted classification systems as well as for thesaurii.
4 new Published Subject Indicator sets have been created to accompany this paper:
A shameless trail for a new paper...
XML Europe time shall soon be upon us once again, and Techquila's Kal Ahmed shall be presenting a new paper on the application of topic maps in a peer-to-peer information sharing system.
The paper describes the implementation of a peer-to-peer system based on the JXTA P2P toolkit and TM4J topic map engine which allows peers to browse each other's topic map files and which makes a lot of use of the merging facilities of topic maps to seamlessly integrate information from many peers into a single navigable view.
The application (which will be demonstrated during the presentation) also makes use of the TouchGraph dynamic graph visualisation software and the TMNav topic map UI toolkit (currently a subproject of TM4J).
The paper will be posted to this site shortly...watch this space!