UNIT 3 – Transportation and Assignment Models in Operations Research Notes

In the world of Operations Research, efficiency is everything. Once businesses know how to formulate problems and find optimal solutions using methods like the simplex, the next challenge is often about moving goods and assigning resources in the most cost-effective way. This is where Transportation and Assignment Models become the star performers, helping organizations save time, money, and resources without compromising service quality.

Transportation and Assignment Problems

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The Transportation Problem – Delivering Goods at Minimum Cost

The transportation problem is a special type of Linear Programming problem that focuses on minimizing the cost of shipping goods from multiple origins (factories, warehouses) to multiple destinations (markets, distribution centers) while meeting supply and demand constraints.

The goal is simple but powerful: ensure every demand point is met without exceeding the available supply at each origin—and do it at the lowest possible cost.

To find an initial feasible solution, several methods can be used:

  • North-West Corner Method (NWCM) – Starts filling shipments from the top-left (north-west) corner of the cost table, moving right and down. It’s quick and simple but not always cost-efficient.

  • Least Cost Method (LCM) – Prioritizes filling routes with the lowest shipping costs first, aiming for better cost savings from the beginning.

  • Vogel’s Approximation Method (VAM) – Calculates penalties for not choosing the cheapest routes, making it one of the most effective methods for getting close to the optimal solution quickly.

However, finding an initial solution is just the beginning. To reach true optimality, we use the MODI Method (Modified Distribution Method), which checks if a better solution exists and adjusts allocations to reduce total cost even further.

Real-World Importance of the Transportation Model

Think of a large retail chain distributing products across hundreds of stores, or a cement manufacturer sending shipments to various construction sites. Every rupee saved on transportation directly boosts profit margins. The transportation model ensures that such savings happen scientifically, not just instinctively.

The Assignment Problem – The Art of Perfect Matching

While the transportation problem deals with bulk goods, the assignment problem focuses on matching individual tasks or resources in the most efficient way. For example, assigning workers to jobs, machines to tasks, or salespeople to territories. The objective here is to minimize the total time, cost, or distance—or in some cases, maximize the total profit or efficiency.

The most famous solution technique for this is the Hungarian Method, which transforms the problem into a cost matrix and systematically reduces it until the optimal one-to-one matching is found.

Handling Unbalanced and Maximization Cases

In real life, problems aren’t always neat and balanced. Sometimes the number of tasks doesn’t match the number of workers, creating unbalanced problems. In such cases, dummy rows or columns are added to make the problem solvable without changing the logic of the Hungarian Method.

Similarly, not all problems aim to minimize costs—many businesses want to maximize output, profit, or efficiency. This can be handled by converting the maximization problem into a minimization format (usually by subtracting each value from the highest value in the matrix) and then applying the same method.

Business Applications That Save Millions

  • Transportation Model – Used in logistics, supply chain management, manufacturing, and retail distribution.

  • Assignment Model – Applied in HR planning, machine scheduling, sales territory management, and project staffing.

When applied correctly, these models can lead to massive cost savings and efficiency improvements. For global corporations moving thousands of shipments daily, even a 2% reduction in transportation costs can mean millions saved annually.

Conclusion – Smart Movement, Smarter Matching

Transportation and Assignment Models prove that optimization isn’t just about doing the work—it’s about doing it in the smartest way possible. From minimizing shipping costs to ensuring the right person is assigned to the right job, these models give businesses a competitive edge in a fast-paced, cost-conscious world.

With tools like NWCM, LCM, Vogel’s, MODI, and the Hungarian Method, decision-makers can turn complex logistical and resource allocation challenges into clear, actionable solutions. In the language of modern business, this is not just planning—it’s precision engineering for profits.

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