Showing papers by "Indian Institute of Management Calcutta published in 1978"

Redundancy Optimization Through Simplex Pattern Search

Abstract: Optimal allocation of redundancy in a series system with separately maintained repairable subsystems subject to multiple constraints is investigated for maximizing system reliability using simplex pattern search and separable programming. The constraints, besides the usual ones, include one based on s-expected busy periods of the maintenance facilities. A numerical example illustrates the method.

Using the collection-control model

Abstract: In replying to A. Sandison's comments [1] we must note that any model is to some degree a simplification of the real world. Through modeling, alternative approaches and solutions to problems can be studied without jeopardizing the operation of the real system. Time frames can be shortened, unimportant variables can be dropped, and boundary conditions can be determined.

The double ended queue with mixed-Erlangian arrival distribution and limited waiting space

Abstract: The steady state solution of the double-ended queue involving taxis and customers at a taxi stand has been considered under the assumption that there is limited waiting space both for taxis and for customers. Taxis arrive according to mixed Erlangian input, the mean times of stay in the various phases which comprise the arrival channel not being the same. The arrivals of customers are assumed to be Poisson distributed. We obtain an expression for the probabilities that there aren units in the queue. The cases of exponential and 2-Erlang arrival distributions for taxis have been considered as particular cases. For the 2-Erlang arrival distribution for taxis, we have evaluated the probabilities that the waiting space for customers or taxis is full; their values are also shown by means of graphs.