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Operations research and optimization (ORO)

This issue is dedicated to the International Conference on Operations Research and Optimization (ORO2011) which was held at the School of Mathematics, IPM, Tehran, Iran on 26–28 January 2011. The organizers of the conference were the Institute for Research in Fundamental Sciences (IPM) and School of Mathematics, Statistics and Computer Science, University of Tehran (UT). IPM is an Iranian institute which was founded in 1989 under the name ‘Institute for Studies in Theoretical Physics and Mathematics (IPM)’ and its goal is the advancement of research and innovation in theoretical physics and mathematics. The main activity of the IPM is in direction of promoting the culture of research all across the country. UT is the oldest and largest university in Iran. It is the best Iranian university in International university rankings and is known as the symbol of higher education in Iran. School of Mathematics, Statistics and Computer Science of UT is the oldest higher education center for mathematics in Iran. The aim of ORO conferences is to bring together researchers and scientists from all over the world to discuss theoretical and applied aspects of ORO. The conference also aims to construct an atmosphere of cooperation between national institutions as well as international ones which are active in the area of ORO and related disciplines. There were rigorous plenary talks by 7 invited speakers in ORO2011. Moreover, there were 40 contributed talks, selected from among 250 submissions. Some selected high-quality papers as well as some invited papers have been considered for publication in this issue, after completing the standard review process. In the following, we review the accepted papers briefly. In the first paper, Mahdavi-Amiri and Ansari dealt with a structured algorithm for solving constrained nonlinear least-square problems which makes use of the ideas of Nocedal and Overton for handling quasi-Newton updates of projected Hessians. The authors discussed relevant results on global convergence and computational benefits. The authors of the second paper are Alizadeh and Hadjisavvas, who extended the definition of monotone bifunctions. In the new definition, the Fitzpatrick transform of a maximal monotone bifunction is introduced so as to correspond exactly to the Fitzpatrick function of a maximal monotone operator in case the bifunction is constructed starting from the operator.