In the past, we have demonstrated how fuzzy concepts can easily be used in the Johnson algorithm to manage uncertain scheduling on two-machine flow shops. This paper extends application to fuzzy flow shops with more than two machines. A new fuzzy heuristic flow-shop scheduling algorithm (the fuzzy Palmer algorithm) is then designed since optimal solutions seem unnecessary for uncertain environm...

Predicting how changes to the urban environment will affect town centre vitality, mediated as pedestrian flows, is important for environmental, social and economic sustainability. This study is a longitudinal investigation of before and after urban environmental change in a town centre and its association with vitality. The case study baseline is Cardiff town centre in 2007, prior and after maj...

We resolve an open question raised by Feige & Scheideler by showing that the best known approximation algorithm for flow shops is essentially tight with respect to the used lower bound on the optimal makespan. We also obtain a nearly tight hardness result for the general version of flow shops, where jobs are not required to be processed on each machine. Similar results hold true when the object...

Web based systems have been shown to be useful tools for supporting educational communication for teachers and students. In this paper we present such a system, which is an Integrated Distributed Learning Environment (IDLE). We present the technical description of this IDLE and we discuss its main characteristics like the transmission of multimedia data over the network, the manipulation of the...

In shop scheduling, several applications exist where it is required that some components perform consecutively. We refer to no-idle schedules if machines are required to operate with no inserted idle time and no-wait schedules if tasks cannot wait between the end of an operation and the start of the following one. We consider here no-idle/no-wait shop scheduling problems with makespan as perfor...

We consider the NP-hard problem of scheduling n jobs in m two-stage parallel flow shops so as to minimize the makespan. This problem decomposes into two subproblems: assigning the jobs to parallel flow shops; and scheduling the jobs assigned to the same flow shop by use of Johnson’s rule. For m = 2, we present a 32 -approximation algorithm, and for m = 3, we present a 12 7 -approximation algori...