Case-Based Reasoning in a Travel Medicine Application - Computational Intelligence in Healthcare: Advanced Methodologies - page 190

5.1 Knowledge Sources

Considering knowledge sources, different characteristics, and aspects on which
to assess knowledge source properties come to mind. The possible properties can
refer to content (e.g. quality or topicality) as well as meta-information (e.g. an-
swer speed or access limits). These properties do not only describe the individual
sources but are also used for optimizing the query path. When working with dis-
tributed and - most importantly - external sources it is of high importance to be
able to assess, store and utilize their characteristics in order to achieve optimal
retrievalresults.Indetailwehaveidentified the meta and content properties
for knowledge sources (see Table 1, a more detailed description can be found in
Reichle et. al. [19]).

Table 1. Knowledge source properties

Meta Property Content Property

Access Limits Content

Answer Speed Expiry

Economic Cost Up-to-dateness

Syntax Coverage

Format Completeness

Structure
Cardinality
Trust or Provenance

Not all of the properties identified are fully unrelated. Properties like syntax,
format, structure and cardinality for instance are partially related which allows
for some basic sanity checks of their assigned values; also some of the proper-
ties such as answer speed, language or structure can be automatically assessed.
Apart from these possibilities for automation the knowledge source properties
currently have to be assessed and maintained manually by a Knowledge Engi-
neer who assigns values to the properties and keeps them up to date. Adapting
the properties' values based on feedback is only partially possible since feedback
is mostly given on the final, combined result and it is thus dicult to propagate
back to the respective knowledge sources. Also the more differentiated feedback
is needed (in order to be mapped to the respective properties) the less feedback
is given, so a good balance has to be found in this regard. Despite these dif-
ficulties the inclusion of feedback should not be ruled out completely. Even if
good knowledge sources are affected by bad general feedback and the other way
around the mean feedback should still provide a basic assessment of a knowledge
source's content and can for instance be included in a combined quality mea-
sure. Depending on the respective properties we have defined possible values.
Although there are not all properties usable for routing optimization, there are
some properties like format, syntax, structure or content that cannot be used in
the routing process since no valency can be assigned to them, that is one pos-
sible value cannot be judged as better or worse as the other. The computation