fa Mathematical Modeling and Applications of OR Mathematical Modeling and Applications of OR پژوهشی Original Here, we investigate the classical p-median location problem on a network in which the vertex weights and the distances between vertices are uncertain. We propose a programming model for the uncertain p-median location problem with tail value at risk objective. Then, we show that it is NP-hard. Therefore, a novel hybrid modified binary particle swarm optimization algorithm is presented to obtain the approximate optimal solution of the proposed model. The algorithm contains the tail value at risk simulation and the expected value simulation. Finally, by computational experiments, the algorithm is illustrated to be efficient. Location problem, p-median, Uncertainty theory, Tail value at risk, Uncertain programming, Binary particle swarm optimization. 78 93 http://iors.ir/journal/browse.php?a_code=A-10-12-13&slc_lang=fa&sid=1 Fahimeh Baroughi baroughi@sut.ac.ir 1111111111 00031947532846001974 Yes Sahand University of Technology Sahand University of Technology Akram Soltani اکرم سلطانی soltani_akram32@yahoo.com 1111111111 1111111111 No Sahand University of Technology Sahand University of Technology Behrooz Alizadeh بهروز علیزاده alizadeh@sut.ac.ir 1111111111 1111111111 No Sahand University of Technology دانشگاه صنعتی سهند تبریز