Papers in PDF format

HARVEST [29,30] is a more complicated, but conceptually sound approach to access distributed
information. It does not only use full text retrieval but also offers meta tags for structured
information. It operates completely different to robots. The idea is not to search Web servers,
but to rely on the information given by them using gatherers and brokers. Gatherers collect
information about the specified documents on a specified server. They do not only index
HTML documents but also postscript, winword, rich text format, word perfect, framemaker,
etc. For each document, data is stored in the so called Summary Object Interchange Format
(SOIF). Brokers get information of gatherers and other brokers according to defined rules.
Further, brokers offer the searchable data to users.
5 Case study: DOIA
As diagnosis in Dermatology relies heavily on visual information we decided to set up an image
database, a part of which is now offered through the WWW: Dermatology Online Atlas
(DOIA) [31-39]. DOIA is intended to be a basis for a distributed hypermedia textbook of dermatology.
It offers selected images from our slide archive with about 100.000 slides. Right
now it covers basic diagnoses important for student education and an extensive collection of
images from specialists in our hospital. DOIA shall become a distributed resource for reference
and teaching of outstanding quality. With experts around the globe contributing, it will offer up
to date images and expert knowledge.
Some goals will be achieved through the common image atlas. Images will be stored in a standardized
manner and a common language of description will be developed. In Dermatology
there is already a very clear description language available, however, dermatologists tend to
invent new terms for description and the terms used are not really standardized. Giving a terminology
together with reference images may help here. Fast access will be available. It is still
quite common to search for literature in Medline and order the papers. Rare and country specific
diseases will be covered as specialists around the world will be asked to contribute to this
resource. Even more important is that images of different skin types (white, black, asian) will
be available for reference. Skin diseases tend to look completely different on different skin
types and reference images are usually only available for the most common skin type, e.g.
white in Germany. An international reference atlas will help in diagnosis.
5.1 Images
Clinical and histological images were selected from the archive or continuing medical education
(CME) units. These were commercially scanned and stored on PCDs, sometime we also
used a slide scanner. Using a PC Pentium 100 with a miro 40sv graphics card and a miro
2085E monitor plus miro proof for calibration, the images were enhanced and made anonymous.
After manipulation the images and corresponding thumbnails were stored on a magnetooptical
disc and JPEG compressed on hard disc.
Studies [40-43] with clinical photographs (skin, body overview, etc.) have shown that the
resolution of 768x512x24 (1.125MB) is sufficient to see every required detail. Further, it displays
well on most screens, because usual monitor resolutions currently range from 800x600 to
1600x1200. Another study [40] has shown that images at this resolution can be compressed at
about 1:37 with JPEG without loosing diagnostic relevant details. In about 90% of the images
not even any difference could be detected between the original and the compressed one.
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