In many real applications, there are some imprecise data which represented by fuzzy numbers. So, ranking of fuzzy numbers is an important part of the decision process.

The main focus of this special issue will be on the new and existing ranking methods and its application. The special issue will become an international forum for researchers to summarize the most developments and ideas in the field, with a special emphasis given to the real applications in the science and engineering problems. Potential topics include, but are not limited to:

• Ranking fuzzy numbers: historical perspective
• Ranking of interval valued fuzzy numbers, vague numbers (intuitionistic fuzzy numbers), and interval valued intuitionistic fuzzy numbers
• Fuzzy linear and nonlinear programming using ranking approach
• Fuzzy linear system of equations using ranking methods
• Approximating fuzzy numbers
• Fuzzy clustering in ordering

Before submission authors should carefully read over the journal's Author Guidelines, which are located at http://www.hindawi.com/journals/mpe/guidelines/. Prospective authors should submit an electronic copy of their complete manuscript through the journal Manuscript Tracking System at http://mts.hindawi.com/submit/journals/mpe/rfne/ according to the following timetable: