Handling multi-lean measures with simulation and simulated annealing

This paper describes a simulation-based approach for developing a lean production system of multi-lean measures. Three lean measures are defined to characterize the leanness of the underlying production system: productivity, cycle time, and work-in-process inventory. An optimized setting to certain operational parameters is determined so that a best tradeoff of the three lean measures is reached. The problem formulation results in a multi-objective optimization problem with no closed-form definition of problem objective functions and constraints. The solution approach utilizes Discrete Event Simulation (DES) to deploy lean techniques and model lean measures under process variability and plant constraints and dynamics. A direct search method (i.e., Simulated Annealing (SA)) is used to search of problem domain. A model-based Value Mapping (VM) is used for combining the conflicting multi-lean measures and guiding the SA search for optima. The DES model is also used to develop a future state dynamic Value Stream Map (VSM) of the optimized production process. The approach is applied to an example production system where the capacity of material handling conveyors and the size of maintenance crew are optimized to develop a lean system in terms of three lean measures. Little’s formula is used to verify the simulation assessment of lean measures. Optimization results are also used to demonstrate the conflict among lean measures, the impact of process variability on lean measures, and the role of VM in reaching an efficient tradeoff of multi-lean measures.     

The Impact of Implementing an Educational Project, the Solar Village, on Pupils, Teachers, and Parents

In this project, we suggest building a real model of solar village inside schools, which use only solar energy. Such projects emphasize the importance of energy for a technological society and the advantage of alternative energy sources. In this study, we report on pupils in the 6th grade in three elementary schools in Israel who were active participants in building systems that use solar energy. The study objective was to examine the educational, social, and scientific impact of this project on students, parents, and teachers. The study results showed that the three groups (students, parents, and teachers) highly appreciate the project, educationally and socially. Parents supported the project because they observed the positive impact on their children's learning. Teachers rated the project highly because of students' interaction and involvement, as well as their increases in learning skills such as developing reading plans and executing research and writing reports.