The proceedings contains the papers selected for the 4th International Conf- ence on Knowledge Science, Engineering and Management (KSEM). The c- lection of papers represent the wide range of research activities that have been carriedout,coveringknowledgerepresentationandreasoning,knowledgeextr- tion, knowledge integration, data mining and knowledge discovery, etc. Ad- tionally, two special sessions:"Theoryand Practiceof Ontologyfor the Semantic Web" and "Application of Data Mining to Seismic Data Analysis for Earthquake Study" have been included along with the main conference program. All of the papers havebeen peer reviewedby the members of the ProgramCommittee and external reviewers; 45 regular papers and 12 short papers were selected. They represent the state of the art of research in KSEM-related research areas. The International Conference on Knowledge Science, Engineering and M- agement in 2010 was the fourth event in the series of successful conferences, previously held in Guilin, China, Melbourne, Australia, and Vienna, Austria. It speci?cally focused on becoming a premier forum for prototype and deployed knowledge engineering and knowledge-based systems. KSEM o?ers an exc- tional opportunity for presenting original work, the latest scienti?c and te- nological advances on knowledge-related systems, and discussing and debating practical challenges and opportunities for the research community. A great many people contributed to making KSEM2010 a successful conf- ence. First of all, we would like to thank the KSEM2010 Organizing Committee and the School of Computing and Mathematics and the University of Ulster for providing crucial support throughout the organization of the conference.