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5.2 The local database<br />

Us<strong>in</strong>g standardized and additionally developed hierarchical key systems the images were described.<br />

Data <strong>in</strong>put was done us<strong>in</strong>g a Visual Basic front-end to the database. The description is<br />

stored <strong>in</strong> a database, whereas the image rema<strong>in</strong>s <strong>in</strong> the file system, because MS Access, which<br />

we use for our local database, had some trouble with stor<strong>in</strong>g images. In addition, <strong>in</strong> the file<br />

system images can be used by the database as well as <strong>in</strong> local HTML documents.<br />

5.3 Mapp<strong>in</strong>g the local Database to the Web<br />

We offer different ways to access our database through the Web:<br />

1. We generate a static access structure to the images us<strong>in</strong>g diagnoses (alphabet, ICD).<br />

2. Additional tags are stored as meta <strong>in</strong><strong>format</strong>ion for HARVEST and robots. Full text retrieval<br />

is offered us<strong>in</strong>g HARVEST with GLIMPSE and WAIS. This query <strong>in</strong>terface suffices for<br />

most applications.<br />

3. A gateway to an INFORMIX database is offered that has been designed us<strong>in</strong>g GSQL, a<br />

local client and a remote database demon. The local client passes SQL to the database demon<br />

which returns the results as a set of rows. For the HTML output we use the powerful<br />

text manipulation features of PERL. Updates of the INFORMIX database are done by FTP<br />

and the load utility of INFORMIX with a subset of our local database. The database demon<br />

can be also contacted directly by the browser via HTTP, e.g. if queries are <strong>in</strong>cluded as l<strong>in</strong>ks<br />

<strong>in</strong>to documents.<br />

User comments for image documents are supported. These comments are stored <strong>in</strong> the database,<br />

a log file, and the diagnosis access structure. For updates of the local database the log file<br />

is used. For retrieval of images stored <strong>in</strong> Erlangen, the database solution is very powerful,<br />

however, an architecture based on the HARVEST system provides some text based search<br />

ability and allows to build a distributed image „database“ for Dermatology easily.<br />

5.4 Acceptance and user profile<br />

Usage statistics and personal communication show that the image atlas is used enthusiastically.<br />

In the end of 1994 we had about 200 document requests per day, now (8/96) there are more<br />

than 10.000, a big number consider<strong>in</strong>g that very specialized <strong>in</strong><strong>format</strong>ion is given which is only<br />

of <strong>in</strong>terest to dermatologists. Surpris<strong>in</strong>gly, about 30% of the requests came from America despite<br />

the slow connection.<br />

In this summer we conducted a user survey. In about two months we got 200 answers. The<br />

result is quite <strong>in</strong>terest<strong>in</strong>g because it gives some <strong>in</strong>sight about the users of our server. A short<br />

summary of the results:<br />

• International access is quite common only about 50% of the users came from Europe<br />

• 83% of our users use a PC, 13% a Mac, and 4% a workstation<br />

• 80% of the browsers were Netscape Navigator, 7% of Microsoft Internet Explorer<br />

• Over ten different versions of Netscape Navigator were used from different platforms go<strong>in</strong>g<br />

back to version 0.9b<br />

• Over 75% of the users found our offer onl<strong>in</strong>e, and more than half of these used search eng<strong>in</strong>es<br />

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