31 research outputs found
An Aggregate Production Planning Strategy Selection Methodology based on Linear Physical Programming
In this paper, a multi-objective model for aggregate production planning is presented which includes two objectives: (1) minimized cost and (2) minimized effect on the workforce motivation level caused by hire/layoff decisions. Then, six strategies are considered and the most appropriate one is determined to structure the plan. These strategies are set the regular time production quantities in a certain value which is unique for each. A preference based optimization method called Linear Physical Programming (LPP) is used to solve the model. A forecasting phase which chooses the convenient method to forecast the demand for planning horizon is embedded to study in addition to application of LPP to an APP model as another key contribution of this paper
A Strategic Planning Methodology for the Multimodal Transportation Systems: A Case Study from Turkey
Transportation costs have an important effect on companies’ competition capability in various sectors. To realize a positive effect, transportation industry should provide some specific performance criteria related with the economical efficiency and service quality. Also an increase in this performance degree depends on the obtaining optimum results of using the logistical resources in a convenient manner by the specialized logistics service providers. In this study, considering the effects of transportation modes on constituting a methodology that is interested in a strategic subject like constructing a transportation network is emphasized. In the process of selecting the most convenient transportation modes, all the required criteria are determined considering the related literature and the opinions of the experts. Then the analytical network process methodology is used to solve this selection problem. The close relationship between the transportation modes that will be used among the points in the network and the points that will be used for short storages and transshipment activities is considered. And the analytical network process is again used to select the most convenient ones among the alternative port locations. After decision making on these two important points, optimizing the freight flow among the supply chain by choosing the right transportation modes at each stage is aimed. To realize that optimization, the aims of decision makers from different levels or from different functional areas are satisfied by using the multilevel programming technique. Finally, the proposed methodology is applied on a transportation project of a logistic service provider, which gives service in a multimodal, multicommodity, multilevel and multiechelon transportation network
Selecting container port via a fuzzy ANP-based approach: A case study in the Marmara Region, Turkey
In this case study, a real world problem of a production firm in the Marmara Region, Turkey was considered. In the current situation, the firm works with different third-party logistics firms and uses different ports each time. However, they have some quality problems and decided to work with a logistics firm by using the most convenient port alternative. A number of conflicting qualitative and quantitative criteria exist for evaluating alternative ports. Qualitative criteria are often accompanied by ambiguities and vagueness. To cope with this problem, the fuzzy analytic network process (FANP) method is used in this study. First, we defined the region specific criteria consisting of the twenty sub-criteria under the six main criteria clusters that influence the selection of container port. Then seven alternative container ports located in the Marmara Sea were determined. The results showed that the most convenient district for the container port is Istanbul District, which is one of the biggest economical centers in Eastern Europe.Analytic network process (ANP) Fuzzy sets Port selection