In 1977, Freeman formalised generic measures of Social Networks Analysis (SNA). Then, the Web "2.0" social networks have become global networks (e.g., FaceBook, MSN). This thesis defines a semantic model, non probabilist and predictive, for the decisional analysis of professional and institutional social networks. The presented multidisciplinary model, in parallel to the Galam's sociophysics, integrates some semantic methods of natural language processing and knowledge engineering, some measures of statistic sociology and some electrodynamic laws, applied to the economic performance and social climate optimisation. It has been developped and experimented in line with the Socioprise project, funded by the French State Secretariat for the prospective and development of the digital economy.
