Operations Research · Unit 4
Assignment Problems
Exam-focused notes for Assignment Problems (Operations Research, ORS255): what the TU syllabus asks and how it has actually been tested, with 7 solved past questions from this unit.
What this unit covers
- Formulation of assignment problems
- Hungarian Assignment Method (HAM)
- One-to-one assignment constraints
- Minimization and maximization in assignments
- Optimal solution finding
Hungarian Assignment Method
Assignment Problem: Least Cost Allocation
A publication employs typists on an hourly basis. There are five typists for service and their charges are different. According to earlier understanding, only one job is given to one typist. Find the least cost allocation for the following data.
$$\begin{array}{|c|ccccc|}\hline \text{Typists/Jobs} & P & Q & R & S & T \ \hline A & 85 & 75 & 65 & 125 & 75 \ \hline B & 90 & 78 & 66 & 132 & 78 \ \hline C & 75 & 66 & 57 & 114 & 69 \ \hline D & 80 & 72 & 60 & 120 & 72 \ \hline E & 76 & 64 & 56 & 112 & 68 \ \hline \end{array}$$
[5]
Cost matrix (typists A-E vs jobs P-T): Typists P Q R S T ------------------------ A 85 75 65 125 75 B 90 78 66 132 78 C 75 66 57 114 69 D 80 72 60 120 72 E 76 64 56 112 68 Objective: assign one job to each typist minimizing total cost (Hungarian method). Ro...
Full solved answer →Assignment Problem - Hungarian Method
A software company wants to assign its technical support agents to different regions to maximize customer satisfaction. The company has four agents, each with varying effectiveness in different regions. The table below shows the expected satisfaction score if each agent is assigned to a specific region. Use the Hungarian method to assign each technical support agent to a region in a way that maximizes overall customer satisfaction.
$$\begin{array}{|c|cccc|}\hline \text{Regions/Agents} & \text{Sandip} & \text{Sanjay} & \text{Shankar} & \text{Subhash} \ \hline \text{Kathmandu} & 140 & 146 & 148 & 136 \ \hline \text{Biratnagar} & 148 & 132 & 136 & 129 \ \hline \text{Janakpur} & 149 & 135 & 141 & 138 \ \hline \text{Butwal} & 130 & 146 & 149 & 144 \ \hline \end{array}$$
[5]
Satisfaction score matrix (rows = regions, columns = agents): Region\Agent Sandip Sanjay Shankar Subhash --------------- Kathmandu 140 146 148 136 Biratnagar 148 132 136 129 Janakpur 149 135 141 138 Butwal 130 146 149 144 Objective: Maximize total satisfact...
Full solved answer →The ABC Company Job Assignment Problem
The ABC company has three jobs to be done on three machines. Each job must be done on one and only one machine. The cost of each job on each machine is given in the following table. By using Hungarian method, find the job assignments which will minimize the machine cost.
$$\begin{array}{|c|c|c|c|}\hline \text{Jobs\backslash Machine} & X & Y & Z \ \hline A & 4 & 6 & 8 \ B & 2 & 3 & 4 \ C & 4 & 8 & 5 \ \hline \end{array}$$
[5]
Cost matrix (Jobs A, B, C on Machines X, Y, Z): $$\begin{array}{cccc}\hline \text{Job/Machine} & X & Y & Z \\ \hline A & 4 & 6 & 8 \\ B & 2 & 3 & 4 \\ C & 4 & 8 & 5 \\ \hline \end{array}$$ Objective: minimize total assignment cost, each job to exactly one m...
Full solved answer →Assignment Problem - Hungarian Method
Kathmandu Metropolitan is putting up bids for four used motorbikes company. The Metropolitan allows individuals to make bids on all four motorbikes company but will accept only one bid per individual. Four individuals have made the following bids (in thousands Rs.). Make the use of Hungarian method to assign the individuals to different motorbike company in order to maximize the revenue.
$$\begin{array}{|c|c|c|c|c|}\hline \text{Individuals} & \text{Honda} & \text{Hero} & \text{Bajaj} & \text{Yamaha} \ \hline A & 100 & 90 & 110 & 90 \ B & 110 & 100 & 95 & 95 \ C & 105 & 95 & 90 & 105 \ D & 115 & 100 & 95 & 100 \ \hline \end{array}$$
[10]
Profit matrix (bids in thousands Rs.), one bid accepted per individual: Individual Honda Hero Bajaj Yamaha --------------- A 100 90 110 90 B 110 100 95 95 C 105 95 90 105 D 115 100 95 100 Objective: maximize total revenue via one-to-one assignment. --- Maxi...
Full solved answer →Describe Hungarian Assignment Method (HAM) used for finding the optimal solution of assignment problem. [5]
The Hungarian Assignment Method is an algorithm used to solve the assignment problem optimally, where the objective is to assign n jobs to n workers (or resources to tasks) such that the total cost is minimized (or profit maximized) with each job assigned t...
Full solved answer →Assignment Problem - Hungarian Method
A marketing manager has four salesmen and four sales districts. Considering the capabilities of the salesmen and nature of districts, the marketing manager estimates that sales per month in hundreds of rupees for each salesman in each district would be as follows:
$$\begin{array}{|c|c|c|c|c|}\hline \text{Sales} & A & B & C & D \ \hline P & 32 & 38 & 40 & 28 \ Q & 40 & 24 & 28 & 21 \ R & 41 & 27 & 33 & 30 \ S & 22 & 38 & 41 & 36 \ \hline \end{array}$$
Make the use of Hungarian method to assign the salesmen in different districts in such a way that total sales would be maximized. [5]
Sales matrix (hundreds of rupees), salesmen P, Q, R, S vs districts A, B, C, D: Sales A B C D ------------------- P 32 38 40 28 Q 40 24 28 21 R 41 27 33 30 S 22 38 41 36 Objective: Maximize total sales. Subtract every element from the maximum value $41$ (re...
Full solved answer →Formulation of assignment problems
There are three jobs P, Q and R to be completed on four machines A, B, C and D. The costs of performing the different jobs on machines are given below. Assign the jobs to different machines to minimize the total cost of performing the jobs on machines.
$$\begin{array}{|c|c|c|c|c|}\hline \text{Jobs/Machines} & A & B & C & D \ \hline P & 90 & 120 & 140 & 160 \ Q & 40 & 65 & 85 & 95 \ R & 50 & 75 & 95 & 110 \ \hline \end{array}$$
[5]
Cost matrix (3 jobs × 4 machines): Jobs/Machines A B C D --------------- P 90 120 140 160 Q 40 65 85 95 R 50 75 95 110 - 3 jobs (P, Q, R), 4 machines (A, B, C, D) - Objective: minimize total cost. More machines than jobs, so add a dummy job S with all zero ...
Full solved answer →Make Unit 4 stick
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