Criticality of Response Time in the usage of Metaheuristics in Industry

Metaheuristics include a wide range of optimization algorithms. Some of them are very well known and with proven value, as they solve successfully many examples of combinatorial NP-hard problems. Some examples of Metaheuristics are Genetic Algorithms (GA), Simulated Annealing (SA) or Ant Colony Optimization (ACO). Our company is devoted to making steel and is the biggest steelmaker in the world. Combining several industrial processes to produce 84.6 million tones (public official data of 2015) involves huge effort. Metaheuristics are applied to different scenarios inside our operations to optimize different areas: logistics, production scheduling or resource assignment, saving costs and helping to reach operational excellence, critical for our survival in a globalized world. Rather than obtaining the global optimal solution, the main interest of an industrial company is to have "good solutions", close to the optimal, but within a very short response time, and this latter requirement is the main difference with respect to the traditional research approach from the academic world. Production is continuous and it cannot be stopped or wait for calculations, in addition, reducing production speed implies decreasing productivity and making the facilities less competitive. Disruptions are common events, making rescheduling imperative while foremen wait for new instructions to operate. This position paper explains the problem of the time response in our industrial environment, the solutions we have investigated and some results already achieved.