Research on Zero-Wait Scheduling Problems in Multiproduct Processes with Due Dates - Intelligent Computing for Sustainable Energy and Environment - page 322

Research on Zero-Wait Scheduling Problems
in Multiproduct Processes with Due Dates
Zhenhao Xu and Xingsheng Gu
Key Laboratory of Advanced Control and Optimization for Chemical Processes, Ministry of
Education, East China University of Science and Technology, Shanghai 200237, China
{xuzhenhao,xsgu}@ecust.edu.cn
Abstract. Production scheduling is an important aspect of batch process
operations to achieve high productivity and operability. In this paper, we
considered a zero-wait multiproduct scheduling with due dates under
uncertainty, where the total weighted earliness/tardiness penalty is to be
minimized. The imprecise processing time is expressed with the triangle fuzzy
variable and the model has been established based on fuzzy cut-set theory. A
new improved shuffled frog-leaping algorithm (ISFLA) is introduced to search
optimal objective for the given problem, which has a new updating rule in
memeplexes. In order to enhance the ability to search the global optimum, the
strategy of Forced Moving of the worst frog in each sub-memeplex is proposed
to increase the diversity. Simulated results demonstrate that ISFLA has
outperformed the conventional SFLA, which is effective and robust in solving
the zero-wait scheduling with due-date window.
Keywords: zero-wait, uncertainty, SFLA, forced moving.
1 Introduction
Products manufactured by batch processes are commonly of high-value and low-volume,
such as specialty chemicals, pharmaceuticals, agricultural, food and consumer products,
and most recently the constantly growing spectrum of biotechnologyenabled products
[1]. Batch plants are frequently required to handle the manufacturing of more than one
product and are flexibly designed to meet varying product requirements due to market
fluctuations. So, scheduling in batch processes with constrained resources is a very
complex but important problem.
In a batch plant, intermediate storage between processing units is also important to
maintain smooth flow of materials and to satisfy the requirements of processing
recipes. The different types of intermediate storage policies which have been
frequently studied [2]. A ZW scheduling problem occurs in a production environment
in which a product must be processed until completion without any interruption either
on or between processing units. This situation is encountered in a variety of industrial
processes, for example, in chemical and pharmaceutical industries where a series of
processes must follow one another immediately owing to the chemical instability of
intermediate products [3]. The ZW scheduling belongs to the NP-complete class of