35 Kinds of Knowledge Maintenance

Situated cognition motivates a review of knowledge maintenance. If knowledge is situated, then a symbolic knowledge base will require modi-cation as the situation changes. We examine the AI and software engineering literature which relates to acquiring and changing programs. Based 5 on a reverse engineering of that literature, we see that strategies have been ooered to maintain diierent types of knowledge: words; sentences; behavi-oural knowledge; and meta-knowledge. Meta-knowledge divides into problem solving methods; quality knowledge; x knowledge; social knowledge; and processing activities. We see several kinds of processing activities in 10 the literature: acquire; operationalise; fault; x; and preserve. To date, no single strategy maintains all types of knowledge or performs all processing activities. However, we can say that many of these processing activities perform some kind of search space reeection. We can use this framework as follows. By using the quality knowledge, we can track the change in 15 the quality of the knowledge base (KB) over time; i.e. we can assess the value of the knowledge maintenance strategy used in some system. When we have such a record of KB quality vs time, we can assess the impact of situated cognition on symbolic knowledge bases. If knowledge maintenance is tamed (i.e. KB quality is observed to to satisfactory over the 20 lifetime of a changing KB), then we would declare that situated cognition is a solved problem for KBS development.