35 th International Conference on Computers and Industrial Engineering 2107 DIFFICULTIES OF FACILITY LAYOUT PROBLEMS AND SOME RESULTS FOR HEURISTIC ALGORITHMS Ramazan Yaman 1 , Kadriye Ergün 1 , Gülşen Yaman 2 , Necati Özdemir 3 1 ryaman@balikesir.edu.tr, kergun@balikesir.edu.tr Department of Industrial Engineering, Engineering and Architectural Faculty, Balikesir University, Cagis Campus, Balikesir, 10145, Turkey 2 gyaman@balikesir.edu.tr Department of Mechanical Engineering, Engineering and Architectural Faculty, Balikesir University, Cagis Campus, Balikesir, 10145, Turkey 3 nozdemir@balikesir.edu.tr Department of Mathematics, Faculty of Science & Arts, Balıkesir University, Balikesir, 10100, Turkey Abstract: Generally, heuristic optimization algorithms have been used for facility layout problems. One of the difficulties with these heuristic algorithms is to assess their performances. In this study, some case facility layout problems and their optimum results have been presented and their optimum solutions may be used for heuristic algorithms’ performances assessments. Keywords: Optimization Classification, Discrete Optimization, Facility Layout Design 1. Introduction General optimization problems have been taken attention since early ages. First important achievements have been encountered during 18. Century by Newton, Leibnitz, Lagrange and Cauchy in general mathematical developments (Bal, 1995). These mathematical achievements have been used for well-behaved and defined functions. However, general mathematical approaches cannot handle real life problems with satisfactory solutions. After The Second World War, new numerical approaches have been developed for optimization problems. In these achievements, there are two main reasons which are computing technology and applications of numerical techniques. They have overcome many difficulties of general mathematical approaches. Optimization problems have been classified with different ways. Figure 1. shows a classification of the optimization problem. This is presented in official web site of the NEOS, (2005). The second classification is from (Rardin, 1998). He represents that the optimization is a whole system, having subsections (see Figure 2.). However, these classifications are not certain and not accepted by the entire optimization milieu. A classification has also been made by the authors. It has some differences with NEOS classification, because they believe that Discrete Optimization Problems may be considered in the Constrained Optimization (Figure 3.). Because, when a continuous problem has constraints, it will be discrete problem. As mentioned earlier, other classifications on the optimization problems can be found in related to literature and all of them are free to discussions.