| This dissertation presents a new cost-based concurrent layout-materials handling system design technique that takes into account flexibility in department shapes, manufacturer guidelines on equipment usage, and limitations on the ergonomic deployment of materials handling operators. The methodology is aimed at providing management with the "optimal" layout, materials handling equipment portfolio, and the number and skill of materials handling operators. A cost-based discrete-plane layout algorithm adapting materials handling system design in layout development is developed. The cost function accounts for machine availability, machine capacity, investment and operational costs of equipment, manufacturer recommendations for usage of equipment, operator availability, and ergonomic usage of operators. A two-stage greedy-simulated annealing algorithm adapting the characteristics of the best available solutions in the estimation of simulated annealing computational parameters is proposed. The algorithm is aimed at decreasing the computational times of classical single stage simulated annealing algorithms while maintaining high quality solutions. The algorithm benefits from the fast convergence of greedy algorithms and the high quality results of simulated annealing procedures attained through exploring alternatives with inferior objective function values. The algorithm takes the properties of the noise range of the simulated annealing algorithms into consideration to obtain a proper melting temperature for the initial solution attained through the greedy heuristic to reduce the simulation time of the simulated annealing stage. The algorithm is tested in layout environments where palletized products are transported between departments using variable path manual and powered trucks. |
