The S-graph framework is an approach to solving
batch process scheduling problems in
chemical plant
A chemical plant is an industrial process plant that manufactures (or otherwise processes) chemicals, usually on a large scale. The general objective of a chemical plant is to create new material wealth via the chemical or biological transfor ...
s.
S-graph is suited for the problems with a non-intermediate storage (NIS) policy, which often appears in chemical productions, but it is also capable of solving problems with an unlimited intermediate storage (UIS) policy.
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Overview
The S-graph representation exploits problem-specific knowledge to develop efficient scheduling algorithm
In mathematics and computer science, an algorithm () is a finite sequence of Rigour#Mathematics, mathematically rigorous instructions, typically used to solve a class of specific Computational problem, problems or to perform a computation. Algo ...
s.[ In the scheduling problem, there are products, and a set of tasks, which have to be performed to produce a product. There are dependencies between the tasks, and every task has a set of needed equipment that can perform the task. Different processing times can be set for the same task in different equipment types. It is possible to have more pieces of equipment of the same type, or define changeover times between two tasks performed on a single piece of equipment.
There are two types of the scheduling problems that can be handled:
*The number of product batches to produce is set, and the goal is to minimize the makespan (processing time).
*Every product has an associated revenue, and a time horizon for production is set. The objective is to maximize the revenue in this fixed time horizon. S-graph framework also contains ]combinatoric
Combinatorics is an area of mathematics primarily concerned with counting, both as a means and as an end to obtaining results, and certain properties of finite structures. It is closely related to many other areas of mathematics and has many ap ...
algorithm
In mathematics and computer science, an algorithm () is a finite sequence of Rigour#Mathematics, mathematically rigorous instructions, typically used to solve a class of specific Computational problem, problems or to perform a computation. Algo ...
s to solve both of these problems.
References
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External links
S-graph website (archived)
Job scheduling