Agents and multi-agent systems are related to the modern software which has long been recognized as a promising technology for constructing autonomous, complex and intelligent systems. A key development in the field of agent and multi-agent systems has been the specification of agent communication languages and formalization of ontologies. Agent communication languages are intended to provide standard declarative mechanisms for agents to communicate knowledge and make requests of each other, whereas ontologies are intended for conceptualization of the knowledge domain. In this paradigm cognitive agents of heterogeneous nature possess diverse conceptual views and ontologies the problem of semantic mismatch arises, and a special conflict resolution strategies based on computer-supported negotiation are necessary.