Monthly Archives: April 2004

Notes on “Metadata Principles and Practicalities”

Academic Papers, , ,

Metadata Principles and Practicalities, Duval, Erik, Wayne Hodgins, Stuart Sutton, Stuart L. Weibel (2002).

This was a pretty straight-forward reading. I did like the Lego metaphor for metadata, but it would be nice if it was elaborated on a little bit more. So, kids have no problem combining space ship Lego parts with medieval castle parts, but just because it is possible to do so, is it beneficial or useful in any way? I understand they are just talking about modularity as a quality at the point, but it also gives the impression that metadata schema, properly constructed, can be mixed and matched willy-nilly.

One thing I have not seen discussed very much is where the line is drawn between metadata and regular data. For example, most schema have some sort of author/creator field. I see how the author could be data describing and article, but if you look at articles in a journal or on a web page, the author is almost always presented along with the body text. A more clear example of what I’m trying to say is an article’s abstract. I’ve see some schema that have the abstract as a piece of metadata, but does that mean it is not part of the data (the article) itself? Or is it both?

It all depends on your point of view. From a database designer’s perspective, all of theses metadata fields are just data, and metadata is what describes the structure of the database—field types, lengths, foreign key relationships, etc. I’m not saying that everything should be stored in one big lump. I guess I’m just concerned that depending on the point of view, metadata could mean anything. Really, all of this is just a matter of properly separating different data elements from each other. Obviously author/creator should be a separate field from article body text. And date, titles, etc. should be separate as well. But that doesn’t really separate them from the thing itself, they are still all aspects of the thing.

A Thesaurus for Radiological Terrorism Research

Academic Papers, Projects, , ,

Changes in this Edition

A number of changes have been made in this revision. Changes to scope notes, terms, and related terms are highlighted throughout this document. These changes should clarify the precise meaning and use. Sturctural changes to broader and narrower term relationships are explained below.

One of the major structural changes is the removal of “radiological terrorism” as a root word for the entire thesaurus. Putting everything under one term was not my initial idea, but the use of the hierarchical display for both input and output lead me to think that was the preferred structure. I have removed “combating radiological terrorism,” “environmental effects,” “radiation protection,” “radioactive isotopes,” “radioactive material sources,” and “radiological injuries” from under “radiological terrorism.”

Still, I think “radiological terrorism goals,” “radiological terrorism scenarios,” and “radiological terrorism requirements” are necessary parts of “radiological terrorism,” so I have kept the first two in the hierarchy and added the third. This leads to multiple inheritance for “radiological terrorism requirements,” which is both a necessary part of “radiological terrorism” and “intelligence.”

Introduction

The CTRS Radiological Terrorism Thesaurus contains descriptive terms used throughout radiological terrorism literature. The terms, their relationships, and their use were culled from several documents, including:

The thesaurus is presented in three forms: first, an alphabetical display of all included terms, including scope notes, preferred terms and synonyms, broader, narrower and related terms, and any scope notes; second, a hierarchical display of preferred terms only; and third, a rotated display of all terms.

Several relationships may be defined for any term in the thesaurus. Scope Notes (SN) are more detailed descriptions of a term’s use when necessary. A preferred term (USE) is a synonym for the term that has been selected for most uses—non-preferred terms do not show up in the hierarchical view. A non-preferred term (UF) is a synonym that may be found in the literature but is not used in the hierarchy. Broader terms (BT) are terms that represent more general classes of the current term. Narrower terms (NT) represent more specific instances or parts of the current term. Finally, related terms (RT) are related to the current term but not in any of the ways already noted.

View the Thesaurus [pdf]

Notes on the UMLS Semantic Network

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UMLS Semantic Network

This was a really interesting reading. Not interesting like a novel or movie, of course, but interesting because I keep hearing about semantic webs without seeing any worthwhile examples.

One thing I was a little surprised to see was the ASCII codes for creating a flat-file database. I would have through they would have either specified it in XML or something a little more modern. And I kind of cringe whenever I hear anyone call an ASCII file a database. Even though it’s technically true, to me ‘database’ means database management system (DBMS), with some mechanisms put into place to allow multiple users, referential integrity, etc. If everything is stored in ASCII files, than any idiot can ruin the whole system and it’s really, really easy to let data get corrupted. You have to do all sorts of extra work to make sure updates to one field cascade through the rest of the file.

Even through this was designed specifically for the medical field, it’s surprising how much their relationships and semantic types could be useful for almost any semantic web. I could only think of a few relationships that were missing, the chief one being requires. This is a relationship that’s very common in computer science, but I think it might apply fairly often in other fields as well. When and entity requires another it cannot exist without it. It’s kind of a mix between part_of and precedes.