Metode Transportasi | NWC (North West Corner) | Least Cost | VAM (Vogel Approximation Method)

Introduction

This tutorial provides a comprehensive guide to understanding and applying three transportation methods: the North West Corner (NWC) method, the Least Cost method, and the Vogel Approximation Method (VAM). These methods are essential for solving transportation problems in logistics, ensuring efficient allocation of resources while minimizing costs.

Step 1: Understanding the North West Corner Method

The North West Corner method is a simple technique used to find an initial feasible solution for transportation problems.

1. Set up the Cost Matrix:

   • Create a matrix with supply and demand values.
   • Label rows for supply points and columns for demand points.

2. Start at the Top Left Corner:

   • Allocate as much as possible to the cell in the top-left corner (northwest corner).
   • Adjust the supply and demand accordingly.

3. Move to the Next Cell:

   • If supply is fulfilled, move down to the next row. If demand is fulfilled, move to the next column.
   • Repeat allocation until all supplies and demands are satisfied.

4. Practical Tip:

   • Ensure to keep track of remaining supply and demand after each allocation to avoid errors.

Step 2: Applying the Least Cost Method

This method focuses on minimizing transportation costs by evaluating the cost per unit.

1. Identify the Lowest Cost Cell:

   • Examine the cost matrix and find the cell with the lowest transportation cost.

2. Allocate Supply or Demand:

   • Allocate the maximum possible amount to that cell.
   • Adjust the relevant supply and demand figures accordingly.

3. Update the Matrix:

   • Cross out the row or column if the supply or demand is met.
   • Repeat the process, finding the next lowest cost cell.

4. Common Pitfall:

   • Be careful to continually check for remaining supplies and demands to ensure no cell is overlooked.

Step 3: Utilizing the Vogel Approximation Method

VAM is an improved method that provides a better initial solution than the previous methods.

1. Calculate Penalties:

   • For each row and column, calculate the penalty by subtracting the lowest cost from the second-lowest cost.

2. Identify the Highest Penalty:

   • Focus on the row or column with the highest penalty value, as it indicates the most significant cost impact.

3. Allocate in the Corresponding Cell:

   • Allocate as much as possible to the cell with the lowest cost in that row or column.
   • Adjust the supply and demand accordingly.

4. Repeat the Process:

   • Update the matrix and recalculate penalties until all supply and demand are met.

5. Practical Tip:

   • This method often leads to a more cost-effective solution, so it’s beneficial to use it as a first step before optimizing further.

Conclusion

In this tutorial, we covered three essential transportation methods: the North West Corner method for initial feasible solutions, the Least Cost method for minimizing costs, and the Vogel Approximation Method for improved allocations. By following these structured steps, you can efficiently solve transportation problems in logistics. For further optimization, consider applying linear programming techniques to refine your solutions.