Ciencias Exactas y Ciencias de la Salud
Permanent URI for this collectionhttps://hdl.handle.net/11285/551039
Pertenecen a esta colección Tesis y Trabajos de grado de las Maestrías correspondientes a las Escuelas de Ingeniería y Ciencias así como a Medicina y Ciencias de la Salud.
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- The use of Metamodel-based Evolutionary Optimizer for multi-server queuing system design(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2022) Pineda Romero, Carla Vanessa; Batres Prieto, Rafael; emimmayorquin; Espinoza Garcia, Juan Carlos; School of Engineering and Sciences; Campus Monterrey; Santana Reynoso, AlfredoQueuing systems play a vital role in various aspects of our daily lives, from banks and supermarkets to traffic lights, call centers, and production processes. However, many queue systems often fail to work in an efficient way. Traditionally, the design of such systems has relied on models that oversimplify reality. On the other hand, dynamic simulation models can be developed to reflect reality more closely with the possibility of introducing multiple scenarios to analyze the effect of the changes in given parameters. Despite their advantages, the optimization of simulation models of queuing systems is typically achieved through trial-and-error or by means of a large amount of simulation runs obtained through traditional design of experiments techniques. However, this process can be time-consuming and computationally expensive. This research presents an approach for designing an optimum multi-server queuing system applying a surrogate-based optimization algorithm. The said approach aims at speeding up the design of an optimal queue system with stochastic variables. To evaluate the proposed approach, a case study that models a cashier system is conducted. The case study considers stochastic events such as the arrival rate of customers, the number of products they buy, a diversity of prices, and the time each cashier takes to process the purchases. The cashier system is modeled and simulated using the FlexSim simulator software. Several scenarios are analyzed, including different types of cashiers with multiple servers and multiple queues, a single queue with multiple servers, and "fast cashiers” for customers buying a smaller amount of products. The goal is to determine the number of servers (cashiers) required to maximize the Net Present Value (NPV). The proposed approach is compared to two other approaches: experimental design-based optimization (directly with FlexSim simulator), and the Bayesian optimization algorithm. A statistical analysis is carried out for multiple runs of the algorithm to evaluate the proposed approach.
- A hybrid metaheuristic optimization approach for the synthesis of operating procedures for optimal drum-boiler startups(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2020) Garduño Hernández, Emilio; BATRES PRIETO, RAFAEL; 589386; NOGUEZ MONROY, JUANA JULIETA; 202512; PONCE CRUZ, PEDRO; 31857; Batres Prieto, Rafael; RR; Noguez Monroy, Juana Julieta; Ponce Cruz, Pedro; Escuela de Ingeniería y Ciencias; Campus Ciudad de MéxicoA steam generator serves as a power generation equipment that uses the expansive power of the steam to generate electricity. The startup process of a steam generator plays an important role in the ability of a power plant to adjust its electricity generation to changes in demand. As renewable generation plants increase, the levels of variability in electricity production increase. Fast startups become instrumental as they enable traditional power generation plants to provide the quantity of electricity missing when variable renewable energies cannot satisfy demand. A main equipment involved in the startup process of the steam generator is the drum boiler. However, if the startup process is carried out too fast, excessive thermal stresses can occur and provoke damage to the components of the drum boiler. This thesis proposes a dynamic optimization methodology to synthesize operating valve profiles that minimize the startup time of the drum boiler while avoiding the excessive formation of thermal stresses. Since valve operations influence the time-varying behavior of the steam, dynamic simulation is needed in order to evaluate the operating procedure. This thesis proposes a dynamic optimization approach with a hybrid-metaheuristic algorithm that generates the optimal startup procedure of a drum boiler. The proposed algorithm is based on two important elements of two metaheuristic algorithms. Namely, the search zone in the cooling element from the simulated annealing algorithm and the efficient computational performance provided from the tabu search algorithm memory structures. A case study evaluates the proposed approach by comparing it against results previously published in the literature.