This paper presents a state of the art overview on Ants Systems. Initially the work proposes the fundamental concepts of Ants Theory and offers a description of the main algorithms (based on Ants Theory) and the respective fields of application. Among different fields of application, the paper focuses on industrial plants scheduling problems in open shop, flow shop and job shop systems. The las...

scheduling for job shop is very important in both fields of production management and combinatorial op-timization. however, it is quite difficult to achieve an optimal solution to this problem with traditional opti-mization approaches owing to the high computational complexity. the combination of several optimization criteria induces additional complexity and new problems. in this paper, we pro...

In this paper we consider the problem of cyclic schedules such as arise in manufacturing. We introduce a new formulation of this problem that is a very simple modi cation of a standard job shop scheduling formulation, and which enables us to use existing constraint reasoning techniques to generate cyclic schedules. We present evidence for the e ectiveness of this formulation, and describe exten...

Scheduling problems in an open shop is more complicated than others since jobs do not follow a certain route in the system. This study uses computer simulation to compare the performance of different dispatching rules in an open shop. We find that the choice of the best dispatching rule is affected by the utilization factor, due-date factors, and the process time distribution at each station. I...

We consider the High-Multiplicity Cyclic Job Shop Scheduling Problem, in which we are given a set of identical jobs and must find a schedule that repeats itself with some cycle time τ . In each cycle, operations are processed just as in the previous cycle, but on jobs indexed one greater in the ordering of jobs. There are two objectives of interest: the cycle time τ and the flow time F from the...

The problem of maximizing the weighted number of just-in-time jobs in a two-machine ‡ow shop scheduling system is known to be NP-hard [4]. However, the question of whether this problem is strongly or ordinary NP-hard remains an open question. We provide a pseudo-polynomial time algorithm to solve this problem, proving that it is NP-hard in the ordinary sense. Moreover, we show how the pseudo-po...

We consider a robotic ow shop model in which a single robot is responsible for the transportation of parts between machines. For reasons of simplicity, when the shop is to produce a large number of identical parts, the robot usually performs repeatedly a xed sequence of activities. This sequence of activities is called a 1-unit cycle if each execution of the sequence results in the production o...