A. Ayooq; A. Alem Tabriz; A. Javani
Volume 2, Issue 1 , June 2015, , Pages 61-73
Abstract
In this paper, a new mathematical model for the problem of job scheduling in virtual manufacturing cells (VMC) is presented to minimizing the completion time of all jobs. Sequence dependent setup times of machines is considered and lot-streaming is possible. In Virtual manufacturing cells, ...
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In this paper, a new mathematical model for the problem of job scheduling in virtual manufacturing cells (VMC) is presented to minimizing the completion time of all jobs. Sequence dependent setup times of machines is considered and lot-streaming is possible. In Virtual manufacturing cells, each job has a different processing path and there is a set of machines for processing each operation. There are multiple machine types with several identical machines in each type locating in different locations in the shop floor. In this type of system, the cells are not physical and Machines can be shared between the cells. In Mixed-integer nonlinear programming model presented, the scheduling decisions involve assigning a machine to each operation, the start time at each operation, the start time of machines and sub-lot sizes of each job. Some test problems have been generated to demonstrate the implementation of the model and solved by Lingo.
Behrouz Khorshidvand; Ashkan Ayough; Akbar Alem Tabriz
Volume 1, Issue 1 , November 2014, , Pages 72-82
Abstract
In this article, two different systems subject to shocks occurring based on a non-homogeneous Poisson process (NHPP) are analyzed. Type –I system is consisted of a single unit and type –II system is consisted of two parallel units in which both units operate identically and simultaneously. ...
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In this article, two different systems subject to shocks occurring based on a non-homogeneous Poisson process (NHPP) are analyzed. Type –I system is consisted of a single unit and type –II system is consisted of two parallel units in which both units operate identically and simultaneously. In type –I system occurrence of a shock causes system stopping and consequently will be received minimal repairs. Also this system is replaced preventively at time Ψ, or at time less than Ψ due to probable failure. In type –II system a shock to each unit leads to unit stopping and accordingly the unit receives minimal repairs and another unit receives preventive maintenance services with no system stop. Simultaneously, this system is replaced at time Ψ or at times less than Ψ preventively, due to the failure of both units. Systems will be replaced with new and the same types when minimizes total expected cost.