Single-track multi-hoist scheduling problem: a collision-free resolution based on a branch-and-bound approach

2004 ◽  
Vol 42 (12) ◽  
pp. 2435-2456 ◽  
Author(s):  
A. Che ◽  
C. Chu
2008 ◽  
pp. 23-29
Author(s):  
Manuel Mateo Doll ◽  
Ramón Companys Pascual

La fabricación de grandes lotes de un mismo artículo en una línea de producción formada por tanques conlleva una programación cíclica para maximizar la producción. No obstante, queda por decidir cuál es el grado de ciclicidad óptimo, es decir el número óptimo de piezas que deben entrar y salir de la línea durante un ciclo. Para determinarlo se propone un modelo que considera tantas operaciones por tanque como piezas a tratar por ciclo. Dado que un puente-grúa, cuyos movimientos deben programarse, asegura la transferencia de piezas entre tanques, se trata de una variante del HSP (Hoist Scheduling Problem). El objetivo es determinar una secuencia que minimice el tiempo de ciclo. Para ello, hay una comparación entre los diversos grados de ciclos (problema n-cíclico). Se propone un procedimiento de branch-and-bound, con unas cotas apropiadas, que se aplica sobre unos juegos de datos. Los resultados de tiempos de ciclo obtenidos se analizan según los tipos de ventanas temporales y velocidades de grúa.


Author(s):  
José Itzcoatl Gomar-Madriz ◽  
Salvador Hernandez-González ◽  
Jaime Navarrete-Damián

The Hoist Scheduling Problem is combinatory, so tools such as mathematical programming need to be used to get the sequence of movements, respecting the constraints of the process by minimizing the cycle time. A sequence in which the order of movements follows the order of the process is known as the basic diagram. These schedules do not have any clearance for the hoist to make any other movements, resulting in a loss in productivity. This chapter takes the production line of a Mexican factory as a case study, analyzing the hoist's travelling speed to find sequences of movements that could improve productivity. The results of the study indicate that the cycle time has a nonlinear behavior in respect of the hoist's travelling speed and it was determined that there are travelling speeds for which sequences are obtained with enough clearance to make other movements and keep other carriers on the line. A suitable speed was estimated in the case.


Mathematics ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 301 ◽  
Author(s):  
Evgeny Gafarov ◽  
Frank Werner

In this paper, we consider a two-machine job-shop scheduling problem of minimizing total completion time subject to n jobs with two operations and equal processing times on each machine. This problem occurs e.g., as a single-track railway scheduling problem with three stations and constant travel times between any two adjacent stations. We present a polynomial dynamic programming algorithm of the complexity O ( n 5 ) and a heuristic procedure of the complexity O ( n 3 ) . This settles the complexity status of the problem under consideration which was open before and extends earlier work for the two-station single-track railway scheduling problem. We also present computational results of the comparison of both algorithms. For the 30,000 instances with up to 30 jobs considered, the average relative error of the heuristic is less than 1 % . In our tests, the practical running time of the dynamic programming algorithm was even bounded by O ( n 4 ) .


2011 ◽  
Vol 44 (1) ◽  
pp. 8189-8194
Author(s):  
K. Kujawski ◽  
J. Świaojtek

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