D. S. Rohmah

Bio: D. S. Rohmah is an academic researcher. The author has contributed to research in topics: Flow shop scheduling & Job shop. The author has an hindex of 1, co-authored 1 publications receiving 50 citations.

Comparison of dispatching rules in job-shop scheduling problem using simulation: a case study

Abstract: This paper focuses on the development of EQNML which is an extended queuing modelling and markup language. We discuss the DSML metamodel and its XML-based exchange format which represent the cornerstone of the development process. EQNML enhances interoperability between a wide range of analytical solvers and simulation tools dealing with systems performance evaluation and based on the extended queuing theory. Furthermore, the Model Driven Engineering approach allows automatic generation of modelling environments and simulation/analytical codes which improve productivity and quality. Our aim is to induce discussion on and contributions for elaborating the whole metamodel and providing a starting point for the development of a standard inter-change format. 19 refs. (Received in February 2011, accepted in April 2012. This paper was with the authors 2 months for 2 revisions.)

A survey of simulation modeling techniques in production planning and control (PPC)

Abstract: The manufacturing sector as a whole has undergone remarkable changes in terms of scale, complexity and technology over the past decades and this applies across most modern high-technology manufacturing such as electronics, semiconductor, aerospace and automotive industries. In order to remain competitive, manufacturers have to produce high-quality products at low cost, and at the same time retain sufficient flexibility and to meet rapidly changing customer demands. Production planning and control (PPC) is a key role which enables the manufacturer to gain visibility and control over all aspects of manufacturing activities. PPC in itself forms a subject of study, within which simulation techniques have proven themselves to be one of the most practical methodologies available to investigate and evaluate manufacturing issues. In this review paper, we focus on state-of-the art applications of simulation techniques in PPC to demonstrate their applicability to modern manufacturing issues. The review repo...

Evolving dispatching rules for optimising many-objective criteria in the unrelated machines environment

Abstract: Dispatching rules are often a method of choice for solving various scheduling problems. Most often, they are designed by human experts in order to optimise a certain criterion. However, it is seldom the case that a schedule should optimise a single criterion all alone. More common is the case where several criteria need to be optimised at the same time. This paper deals with the problem of automatic design of dispatching rules (DRs) by the use of genetic programming, for many-objective scheduling problems. Four multi-objective and many-objective algorithms, including nondominated sorting genetic algorithm II, nondominated sorting genetic algorithm III, harmonic distance based multi-objective evolutionary algorithm and multi-objective evolutionary algorithm based on decomposition, have been used in order to obtain sets of Pareto optimal solutions for various many-objective scheduling problems. Through experiments it was shown that automatically generated multi-objective DRs not only achieve good performance when compared to standard DRs, but can also outperform automatically generated single objective DRs for most criteria combinations.

Application of EXTENDSIM for Improvement of Production Logistics' Efficiency

Abstract: The article deals with the use of computer simulation approach in order to streamline production logistics within a specific production company. The computer simulation from its very beginnings has undergone a long and significant evolution. The current possibilities of computer simulation approach enable to mimic the real processes of production logistic activities as well as of the actual production. This article is focused on the question, how to effectively utilise the available tools of computer simulation approach to analyse and streamline a particular simulation system. Therefore also the presented solution is the actual description of a practical application of a computer simulation approach used for the needs of one specific production company within one specific industry area. The intention is to showcase the practical aspects of simulation modelling, in this case utilising the EXTENDSIM simulation system. The simulation approach will be used for the needs of a production company, that produces car components and accessories made of wood for the automotive industry. (Received in November 2016, accepted in January 2017. This paper was with the authors 1 month for 2 revisions.)

Simulation Optimization for Operating Room Scheduling

Abstract: This paper presents a case study on operating room scheduling in a small hospital in Chile. Patient flow was represented using a discrete-event simulation model that considered the randomness associated with the primary activities of the entire process, which includes preand posthospitalisation, surgery, surgery setup and recovery. A simulated annealing algorithm was implemented and connected to the simulation model to search for better patient schedules. Additionally, three dispatching rules, Shortest Processing Time (SPT), Longest Processing Time (LPT) and First-In, First-Out (FIFO) were used. The results showed that the simulated annealing approach, based on the Cmax objective function, obtained schedules that were 18 % better than the hospital’s scheduling practices. The utilisation of dispatching rules also has a significant effect in the Cmax indicator. The SPT rule performed better than the hospital schedule in two of the three experiments considered in the study. (Received in March 2014, accepted in January 2015. This paper was with the authors 1 month for 1 revision.)