The paper describes a research project which conducted participatory design in a non-profit organisation based on the work of volunteers. The project is analysed by identifying contradictions in the course of the project, and then fitting these contradictions into the activity theory based, developmental work research framework. It is concluded that the perspectives of contradiction and activit...

Bell's theorem reveals contradictions between the predictions of quantum mechanics and the EPR postulates for a pair of particles only in situations involving imperfect statistical correlations. However , with three or more particles, contradictions emerge even for perfect correlations. We describe an experiment which can be realized in the laboratory, using four-photon entangled states generat...

Web ontology language OWL DL has two-valued model theory semantics so that ontologies expressed by it become trivial when contradictions occur. Based on classical description logic SHOIN (D), we propose the fourvalued description logic SHOIN (D)4 which has the ability to reason with inconsistencies. By transformation technic, we convert the reasoning problems of SHOIN (D)4 to the counterparts o...