A Competitive Genetic Algorithm for Single Row Facility Layout

The single row facility layout is the NP-Hard problem of arranging facilities with given lengths on a line, so as to minimize the weighted sum of the distances between all pairs of facilities. Owing to the computational complexity of the problem, researchers have developed several heuristics to obtain good quality solutions. In this paper, we present a genetic algorithm to solve large SRFLP instances. Our computational experiments show that an appropriate selection of genetic operators can yield high quality solutions in spite of starting with an initial population that is largely randomly generated. Our algorithm improves the previously best known solutions for several benchmark instances and is competitive for the remaining ones.

The Single Row Facility Layout Problem: State of the Art

The single row facility layout problem (SRFLP) is a NP-hard problem concerned with the arrangement of facilities of given lenghs on a line so as to minimize the weighted sum of the distances between all the pairs of facilities. The SRFLP and its special cases often arise while modeling a large variety of applications. It was actively researched until the mid-nineties. It has again been actively studied since 2005. Interestingly, research on many aspects of this problem is still in the initial stages, and hence the SRFLP is an interesting problem to work on. In this paper, we review the literature on the SRFLP and comment on its relationship with other location problems. We then provide an overview of different formulations of the problem that appear in the literature. We provide exact and heuristic approaches that have been used to solve SRFLPs, and finally point out research gaps and promising directions for future research on this problem.

Tabu Search for the Single Row Facility Layout Problem in FMS using a 3-opt Neighborhood

Since material handling agents in a FMS are most efficient when moving in straight lines, a common layout of machines in a FMS is a single row layout. This allows a floor designer to model the problem of generating an optimal machine layout in a FMS as a single row facility layout problem (SRFLP). Due to the computational complexity involved in solving the SRFLP, researchers have developed several heuristics to solve large instances of the problem. In this paper, we present a tabu search implementation based on a 3-opt neighborhood search scheme. We also present a technique to speed up the exhaustive 3-opt neighborhood search process significantly. Our computational experiments show that speed up of the 3-opt search is effective, and our tabu search implementation is competitive. The results we present here are better than the currently known best layouts for several large sized benchmark SRFLP instances, and competitive for other benchmark instances.

Tabu Search for the Single Row Facility Layout Problem Using Exhaustive 2-Opt and Insertion Neighborhoods

The single row facility layout problem (SRFLP) is the problem of arranging facilities with given lengths on a line, while minimizing the weighted sum of the distances between all pairs of facilities. The problem is NP-hard. In this paper, we present two tabu search implementations, one involving an exhaustive search of the 2-opt neighborhood and the other involving an exhaustive search of the insertion neighborhood. We also present techniques to significantly speed up the search of the two neighborhoods. Our computational experiments show that the speed up techniques are effective, and our tabu search implementations are competitive. Our tabu search implementations improved several previously known best solutions for large sized benchmark SRFLP instances.

A Lin-Kernighan Heuristic for Single Row Facility Layout

The single row facility layout problem (SRFLP) is the problem of arranging facilities with given lengths on a line, while minimizing the weighted sum of the distances between all pairs of facilities. The problem is known to be NP-hard. In this paper, we present a neighborhood search heuristic called LK-INSERT which uses a Lin-Kernighan neighborhood structure built on insertion neighborhoods. To the best of our knowledge this is the first such heuristic for the SRFLP. Our computational experiments show that LK-INSERT is competitive and improves the best known solutions for several large sized benchmark SRFLP instances.

A competitive genetic algorithm for single row facility layout

Abstract The single row facility layout is the NP-Hard problem of arranging facilities with given lengths on a line, so as to minimize the weighted sum of the distances between all pairs of facilities. Owing to the computational complexity of the problem, researchers have developed several heuristics to obtain good quality solutions. In this paper, we present a genetic algorithm to solve large SRFLP instances. Our computational experiments show that an appropriate selection of genetic operators can yield high quality solutions in spite of starting with an initial population that is largely randomly generated. Our algorithm improves the previously best known solutions for the 24 instances of 43 benchmark instances and is competitive for the remaining ones

Tuberculous intestinal perforation in a case of Burkitt lymphoma on chemotherapy - A case report

Intestinal perforation induced by chemotherapy in a patient of Burkitt lymphoma is a known potential complication whichcarries high mortality. Perforation may also occur as a result of the transmural nature of the tumour. Patients on chemotherapyare prone to contract infectious diseases due to a compromised immune system. Pulmonary tuberculosis has been reported inthese patients, but abdominal tuberculosis has not. We report the case of a five year old boy on chemotherapy for Burkittlymphoma, and who developed a tuberculous jejunal perforation. The patient underwent drain insertion and stabilizationfollowed by exploratory laparotomy with resection of the pathological segment and closure of the duodenal stump at the fourthpart. Bowel continuity was re-established by gastrojejunostomy. Histopathologic examination of the resected segment revealedintestinal tuberculosis. Anti -tubercular therapy was started and continued for nine months. The last cycle of chemotherapy wasadministered 1 month after surgery. At 1 year of follow up the patient is asymptomatic and thriving well