Concurrent scheduling in dynamic job shop environment

Dissertant

al-Kindi, Lama Adnan Hamid

Thesis advisor

al-Zubaydi, Sawsan Subayh
Qassam, Ala al-Din Hasan

University

University of Technology

Faculty

-

Department

Department of Production Engineering and Metallurgy

University Country

Iraq

Degree

Ph.D.

Degree Date

2010

English Abstract

The aim of this research is to meet customer's due dates and shorten engineer-to-delivery" to increase competition capabilities.

This aim is achieved by ; developing decision aided hybrid techniques to minimize lateness in job orders as much as possible and satisfy customer's due dates.

The scope of the research is directed on heavy equipment's scheduling problem which can be expanded dramatically to cover all types of job shop.

New approach is developed which can be used as a decision aid to enforce the scheduler to do his work effectively.

This is based on hybrid heuristic model which is called Decision Aided Hybrid Heuristic Model (DAHHM), developed from the actual situations of the shop and has the capability to tackle the dynamic cases of such environment in wide and limited research space.

DAHHM has 45 decision rules to be called whenever required for solving scheduling problems to improve scheduling, rescheduling and to eliminate the impact caused by disturbances such as dynamic events.

The developed model consists of five modules that deal with the stages of scheduling / rescheduling paradigm depending mainly on the complexity factor dynamically assigned to each job.

DAHHM modules are ; initializing module, switching module, constraints level module, improve scheduling module and rescheduling module.

DAHHM adopts hybrid techniques such as switching technique, heuristic dispatching rules, and complexity factors regarding the specialty of heavy engineering equipment environment and holonic techniques.

Priority Index rule is developed by using complexity factors such as product physical weight, parts per product, number of workstation required to manufacture the required product ; besides due date and work content.

Three priority indexes rules are developed.

These rules are examined by comparing them with the class of rules involving due dates ; such as Earliest due date and Slack dispatching rules.

Seven scenarios are applied to examine the performance of the developed model including dynamic events such as entering of new jobs, changing due date, job canceling.

The results show improvements toward minimizing tardy jobs in all the applied scenarios and even reaching zero tardy jobs as an optimum scheduling situation in four scenarios out of the seven applied scenarios.

That means optimum solution was reached in 57 % scenarios of the applied scenarios.

The developed Priority indexes B and C adopted, work well in such heavy engineering equipment environment; they have competed EDD and SLACK dispatching rules, they were adopted in three scenarios out of the seven implemented scenarios, i.e.43 %.

To strengthen competition capabilities toward meeting due dates, recommendations focus on adopting the proposed model and the rescheduling policy in the dynamic job shop environment, making use of the developed priority indexes.

Main Subjects

Engineering & Technology Sciences (Multidisciplinary)

Topics

• Management

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-305200