In the paper application of semantic wikis as knowledge engineering toolin a collaborative environment is considered. Selected aspects of semantic wikis are discussed. The main apparent limitation of existing semantic wikis is the lack of expressiveknowledge representation mechanism. Building a knowledge base with a semantic wiki becomes complicated because of its collective nature, where number of users collaboratein the knowledge engineering process. A need for knowledge evaluation and analysis facilities become clear. The paper discusses a new semantic wiki architecture calledPlWiki. The most important concept is to provide a strong knowledge representation and reasoning with Horn clauses-based representation. The idea is to use Prolog clauseson the lower level to represent facts and relations, as well as define rules on top of them. On the other hand a higher-level Semantic Web layer using RDF support is provided.This allows for compatibility with Semantic Media Wiki while offering improved representation and reasoning capabilities. Another important idea is provide an extension toalready available flexible wiki solution (DokuWiki) instead of modifying existing wiki engine. Using the presented architecture it is possible to analyze rule-based knowledgestored in the wiki.

semantic wikis, knowledge engineering, knowledge evaluation