Letter: Closed shop.

Job-shop scheduling in a body shop

We study a generalized job-shop problem called the body shop scheduling problem (BSSP). This problem arises from the industrial application of welding in a car body production line, where possible collisions between industrial robots have to be taken into account. BSSP corresponds to a job-shop problem where the operations of a job have to follow alternating routes on the machines, certain oper...

Letter to the Editor Sensitivity of a pyramidic Wave Front sensor in closed loop Adaptive Optics

The Pyramidic wavefront has a very interesting property: its SNR has a significant increase once the loop is closed, similarly to the Curvature Sensor and contrasting with the Shack-Hartmann one. This result in a gain comparing the Pyramidic and the Shack-Hartmann sensors. It is shown by a combination of descriptive and numerical arguments that this gain is of the order of (D/r0) for low order ...

Shop Cells

In this paper the Group Technology problem of grouping parts in families and machines in cells in order to convert a job shop production system to some pseudo ow shops is considered. Several heuristic methods for solving Group Technology problem have been proposed in the literature, in general, not producing a ow shop in each cell|unless a great number of extra machines is added. We use known t...

Editorial Letter:

Mathematical Models of Flow Shop and Job Shop Scheduling Problems

In this paper, mathematical models for permutation flow shop scheduling and job shop scheduling problems are proposed. The first problem is based on a mixed integer programming model. As the problem is NP-complete, this model can only be used for smaller instances where an optimal solution can be computed. For large instances, another model is proposed which is suitable for solving the problem ...